Co-reporter:Na Niu, Zhuoming Ma, Fei He, Shujun Li, Jian Li, Shouxin Liu, and Piaoping Yang
Langmuir June 13, 2017 Volume 33(Issue 23) pp:5786-5786
Publication Date(Web):May 17, 2017
DOI:10.1021/acs.langmuir.7b00617
Carbon dots, which are less than 10 nm in diameter, have been widely investigated because of their unique luminescence properties and potential for use in bioimaging. In the present work, natural carbon dots (L-CDs) were obtained by molecular aggregation, using ethanol-extracted cellulolytic enzyme lignin. The whole process for the preparation of L-CDs was green and simple to operate and did not use toxic chemical reagents or harsh conditions. The newly prepared L-CDs emitted multicolor photoluminescence following one- and two-photon excitation. The L-CDs also showed good cellular biocompatibility, which is crucial for biological applications. One- and two-photon cell-imaging studies demonstrated the potential of L-CDs for bioimaging.
Co-reporter:Jiating Xu, Piaoping Yang, Mingdi Sun, Huiting Bi, Bin Liu, Dan Yang, Shili Gai, Fei He, and Jun Lin
ACS Nano April 25, 2017 Volume 11(Issue 4) pp:4133-4133
Publication Date(Web):March 20, 2017
DOI:10.1021/acsnano.7b00944
Rare-earth-based upconversion nanotechnology has recently shown great promise for photodynamic therapy (PDT). However, the NIR-induced PDT is greatly restricted by overheating issues on normal bodies and low yields of reactive oxygen species (ROS, 1O2). Here, IR-808-sensitized upconversion nanoparticles (NaGdF4:Yb,Er@NaGdF4:Nd,Yb) were combined with mesoporous silica, which has Ce6 (red-light-excited photosensitizer) and MC540 (green-light-excited photosensitizer) loaded inside through covalent bond and electrostatic interaction, respectively. When irradiated by tissue-penetrable 808 nm light, the IR-808 greatly absorb 808 nm photons and then emit a broadband peak which overlaps perfectly with the absorption of Nd3+ and Yb3+. Thereafter, the Nd3+/Yb3+ incorporated shell synergistically captures the emitted NIR photons to illuminate NaGdF4:Yb,Er zone and then radiate ultrabright green and red emissions. The visible emissions simultaneously activate the dual-photosensitizer to produce a large amount of ROS and, importantly, low heating effects. The in vitro and in vivo experiments indicate that the dual-photosensitizer nanostructure has trimodal (UCL/CT/MRI) imaging functions and high anticancer effectiveness, suggesting its potential clinical application as an imaging-guided PDT technique.Keywords: bioimaging; dual-photosensitizer; IR-808; photodynamic therapy; upconversion;
Co-reporter:Lili Feng, Fei He, Yunlu Dai, Bin Liu, Guixin Yang, Shili Gai, Na Niu, Ruichan Lv, Chunxia Li, and Piaoping Yang
ACS Applied Materials & Interfaces April 19, 2017 Volume 9(Issue 15) pp:12993-12993
Publication Date(Web):April 3, 2017
DOI:10.1021/acsami.7b00651
Photodynamic therapy (PDT) based on Tm3+-activated up-conversion nanoparticles (UCNPs) can effectively eliminate tumor cells by triggering inorganic photosensitizers to generate cytotoxic reactive oxygen species (ROS) upon tissue penetrating near-infrared (NIR) light irradiation. However, the partial use of the emitted lights from UCNPs greatly hinders their application. Here we develop a novel dual-photosensitizer nanoplatform by coating mesoporous graphitic-phase carbon nitride (g-C3N4) layer on UCNPs core, followed by attaching ultrasmall Au25 nanoclusters and PEG molecules (named as UCNPs@g-C3N4–Au25-PEG). The ultraviolet–visible (UV–vis) light and the intensive near infrared (NIR) emission from UCNPs can activate g-C3N4 and excite Au25 nanoclusters to produce ROS, respectively, and thus realize the simultaneous activation of two kinds of photosensitizers for enhanced the efficiency of PDT mediated by a single NIR light excitation. A markedly higher PDT efficacy for the dual-photosensitizer system than any single modality has been verified by the enhanced ROS production and in vitro and in vivo results. By combining the inherent multi-imaging properties (up-conversion, CT, and MRI) of UCNPs, an imaging guided therapeutic platform has been built. As the first report of dual-inorganic-photosensitizer PDT agent, our developed system may be of high potential in future NIR light induced PDT application.Keywords: Au25 nanoclusters; g-C3N4; imaging; photodynamic therapy; photosensitizer; up-conversion;
Co-reporter:Ruichan LvPiaoping Yang, Bo Hu, Jiating Xu, Wenting Shang, Jie Tian
ACS Nano 2017 Volume 11(Issue 1) pp:
Publication Date(Web):December 13, 2016
DOI:10.1021/acsnano.6b07990
In the theranostic field, a near-infrared (NIR) laser is located in the optical window, and up-conversion nanoparticles (UCNPs) could be potentially utilized as the imaging agents with high contrast. Meanwhile, copper sulfide (CuS) has been proposed as a photothermal agent with increased temperature under a NIR laser. However, there is still no direct and effective strategy to integrate the hydrophobic UCNPs with CuS until now. Herein, we propose an in situ growth routine based on the hydrophobic core/shell UCNPs combined with ultrasmall water-soluble CuS triggered by single 808 nm NIR irradiation as the theranostic platform. Hydrophobic NaYF4:Yb,Er@NaYF4,Nd,Yb could be turned hydrophilic with highly dispersed and biocompatible properties through conjunction with transferred dopamine. The as-synthesized ultrasmall CuS (3 and 7 nm) served as a stable photothermal agent even after several laser-on/off cycles. Most importantly, comparing with the mix routine, the in situ growth routine to coat UCNPs with CuS is meaningful, and the platform is uniform and stable. Green luminescence-guided hyperthermia could be achieved under a single 808 nm laser, which was evidenced by in vitro and in vivo assays. This nanoplatform is applicable as a bioimaging and photothermal antitumor agent, and the in situ growth routine could be spread to other integration processes.Keywords: copper sulfide; in situ growth; photothermal; up-conversion;
Co-reporter:Dan Yang, Guixin Yang, Shili Gai, Fei He, Chunxia Li, and Piaoping Yang
ACS Applied Materials & Interfaces 2017 Volume 9(Issue 8) pp:
Publication Date(Web):February 7, 2017
DOI:10.1021/acsami.6b15203
Combined therapy using multiple approaches has been demonstrated to be a promising route for cancer therapy. To achieve enhanced antiproliferation efficacy under hypoxic condition, here we report a novel hybrid system by integrating dual-model photodynamic therapies (dual-PDT) in one system. First, we attached core–shell structured up-conversion nanoparticles (UCNPs, NaGdF4:Yb,Tm@NaGdF4) on graphitic-phase carbon nitride (g-C3N4) nanosheets (one photosensitizer). Then, the as-fabricated nanocomposite and carbon dots (another photosensitizer) were assembled in ZIF-8 metal–organic frameworks through an in situ growth process, realizing the dual-photosensitizer hybrid system employed for PDT via stepwise water splitting. In this system, the UCNPs can convert deep-penetration and low-energy near-infrared light to higher-energy ultraviolet–visible emission, which matches well with the absorption range of the photosensitizers for reactive oxygen species (ROS) generation without sacrificing its efficacy under ZIF-8 shell protection. Furthermore, the UV light emitted from UCNPs allows successive activation of g-C3N4 and carbon dots, and the visible light from carbon dots upon UV light excitation once again activate g-C3N4 to produce ROS, which keeps the principle of energy conservation thus achieving maximized use of the light. This dual-PDT system exhibits excellent antitumor efficiency superior to any single modality, verified vividly by in vitro and in vivo assay.Keywords: carbon dots; g-C3N4; MOFs; synergistic therapy; up-conversion;
Co-reporter:Qing-Feng Li;Zengchen Liu;Lin Jin;Zhenling Wang
RSC Advances (2011-Present) 2017 vol. 7(Issue 70) pp:44614-44618
Publication Date(Web):2017/09/11
DOI:10.1039/C7RA08581H
A water-soluble fluorescent hybrid material has been prepared by functionalization of aminoclay with a fluorescent dye (NDPA). UV-vis absorbance, FT-IR/fluorescent spectroscopy, SEM and TEM techniques were used to investigate its structural, fluorescence and morphological features. The results indicated that the organic fluorescent group can be covalently anchored onto aminoclay through the reaction of the amino-group, and the obtained AC–NDPA exhibited good water solubility and fluorescence properties, coupled with high dispersibility in aqueous solution. Further study found that AC–NDPA had low biotoxicity, and live cell imaging showed that AC–NDPA can be efficiently phagocytized by HeLa cells, bright blue emission can be observed in the cytoplasm and nucleus of HeLa cells by con-focal laser scanning microscopy. We expect that this work could reveal the potential for using the aminoclay based fluorescent material as an effective staining reagent for in vivo bioimaging.
Co-reporter:Lili Feng;Dan Yang;Fei He;Shili Gai;Chunxia Li;Yunlu Dai
Advanced Healthcare Materials 2017 Volume 6(Issue 18) pp:
Publication Date(Web):2017/09/01
DOI:10.1002/adhm.201700502
Reactive oxygen species (ROS) produced in the specific tumor site plays the key role in photodynamic therapy (PDT). Herein, a multifunctional nanoplatform is designed by absorbing ultrasmall upconversion nanoparticles (UCNPs) on mesoporous graphitic-phase carbon nitride (g-C3N4) coated superparamagnetic iron oxide nanospheres, then further modified with polyethylene glycol (PEG)molecules (abbreviated as Fe3O4@g-C3N4–UCNPs–PEG). The inert g-C3N4 layer between Fe3O4 core and outer UCNPs can substantially depress the quenching effect of Fe3O4 on the upconversion emission. Upon near-infrared (NIR) laser irradiation, the UCNPs convert the energy to the photosensitizer (g-C3N4 layer) through fluorescence resonance energy transfer process, thus producing a vast amount of ROS. In vitro experiment exhibits an obvious NIR-triggered cell inhibition due to the cellular uptake of nanoparticles and the effective PDT efficacy. Notably, this platform is responsive to magnetic field, which enables targeted delivery under the guidance of an external magnetic field and supervises the therapeutic effect by T1/T2-weighted dual-modal magnetic resonance imaging. Moreover, in vivo therapeutic effect reveals that the magnetism guided accumulation of Fe3O4@g-C3N4–UCNPs–PEG can almost trigger a complete tumor inhibition without any perceived side effects. The experiments emphasize that the excellent prospect of Fe3O4@g-C3N4–UCNPs–PEG as a magnetic targeted platform for PDT application.
Co-reporter:Dan Yang;Guixin Yang;Ruichan Lv;Shili Gai;Chunxia Li;Fei He;Jun Lin
Advanced Functional Materials 2017 Volume 27(Issue 18) pp:
Publication Date(Web):2017/05/01
DOI:10.1002/adfm.201700371
Photodynamic therapy (PDT), as a minimally invasive and high-efficiency anticancer approach, has received extensive research attention recently. Despite plenty of effort devoted to exploring various types of photodynamic agents with strong near-infrared (NIR) absorbance for PDT and many encouraging progresses achieved in the area, effective and safe photodynamic photosensitizers with good biodegradability and biocompatibility are still highly expected. In this work, a novel nanocomposite has been developed by assembly of iron oxide (Fe3O4) nanoparticles (NPs) and Au nanoparticles on black phosphorus sheets (BPs@Au@Fe3O4), which shows a broad light absorption band and a photodegradable character. In vitro and in vivo assay indicates that BPs@Au@Fe3O4 nanoparticles are highly biocompatible and exhibit excellent tumor inhibition efficacy owing to a synergistic photothermal and photodynamic therapy mediated by a low-power NIR laser. Importantly, BPs@Au@Fe3O4 can anticipatorily suppress tumor growth by visualized synergistic therapy with the help of magnetic resonance imaging (MRI). This work presents the first combination application of the photodynamic and photothermal effect deriving from black phosphorus nanosheets and plasmonic photothermal effect from Au nanoparticles together with MRI from Fe3O4 NPs, which may open the new utilization of black phosphorus nanosheets in biomedicine, optoelectronic devices, and photocatalysis.
Co-reporter:Bin Liu;Xiaoran Deng;Zhongxi Xie;Ziyong Cheng;Jun Lin
Advanced Materials 2017 Volume 29(Issue 36) pp:
Publication Date(Web):2017/09/01
DOI:10.1002/adma.201604878
Oleic acid (OA) and/or oleylamine (OAm) are generally used as the surface ligands for stabilization of inorganic nanocrystals (NCs). The hydrophobic and inert surface of the NCs limits their applications such as in biomedical areas. Hence, surface modifications are essential in many physical and chemical processes. Here, a facile and versatile strategy is reported for the modification of NCs by ultraviolet-induced thiol–ene chemistry, in which thiol-terminated poly(ethylene glycol) (HSPEG) and its derivatives can react directly with double bonds in OA/OAm ligands to form covalent linking within one step. Through this strategy, various hydrophobic NCs with different compositions and morphologies are able to be transferred into water combining with functionalization of active groups. As a proof-of-concept, this strategy is successfully used to construct a sensor for detecting avidin based on upconverting luminescence analysis. Therefore, this strategy provides a new tool for designing and tuning the surface properties of NCs for different applications.
Co-reporter:Shuchao Sun, Jianjiao Zhang, Peng Gao, Ying Wang, Xiaobo Li, Tingting Wu, Yanbo Wang, Yujin Chen, Piaoping Yang
Applied Catalysis B: Environmental 2017 Volume 206(Volume 206) pp:
Publication Date(Web):5 June 2017
DOI:10.1016/j.apcatb.2017.01.027
•The S22− has been successfully introduced into TiO2 nanotubes, which exhibit a serial of 9 nm S22−-doped TiO2 photocatalysts.•The obtained S22− doped TiO2 nanotubes exhibit a full visible-light absorption (from 400 to 800 nm).•The photocatalysts have a highest H2-production rate of 9610 μmol h−1 g−1 and the quantum efficiency (QE) reaches 19.8%.TiO2, as a benchmark photocatalyst for hydrogen production through water splitting, has a relatively large band gap (3.2 eV for anatase and 3.0 eV for rutile) requiring UV light (290–400 nm) for electronic excitations from the valence band to the conduction band, hence utilizing only a small part of the solar spectrum. The construction of new electronic band gap, especially in the visible region (400–800 nm), is of great importance for improving TiO2 optical and photocatalytic properties. In this work, though it is deem metastable and can induce a broad visible-light adsorption in previous literatures, anionic S22− has been successfully introduced into TiO2 nanotubes, which is different from the previous works about S-doped TiO2 that contain only cationic S4+ and S6+. Resultantly, the S22− doped TiO2 nanotubes exhibit a full visible-light absorption (from 400 to 800 nm) and a greatly enhanced photocatalytic H2-production rate under visible-light irradiation (9610 μmol h−1 g−1, about 13.7 and 37 times of other cationic and anion S-doped TiO2 nanoparticles, respectively, almost highest in all the results reported previously in literatures of TiO2 doped with non-metal elements).In this work, the S22−-doped TiO2 nanotubes present a special ability in a full visible light absorption, which greatly enhance photocatalytic activity under visible-light irradiation.Download high-res image (224KB)Download full-size image
Co-reporter:Jiating Xu, Ye Kuang, Ruichan Lv, Piaoping Yang, Chunxia Li, Huiting Bi, Bin Liu, Dan Yang, Yunlu Dai, Shili Gai, Fei He, Bengang Xing, Jun Lin
Biomaterials 2017 Volume 130(Volume 130) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.biomaterials.2017.03.041
Optimal nano-sized drug carrier requires long blood circulation, selective extravasation, and efficient cell uptake. Here we develop a charge-convertible nanoplatform based on Pt(IV) prodrug loaded NaYF4:Yb,Tm upconversion nanoparticles (UCNs), followed by coating a layer of PEG-PAH-DMMA polymer (UCNs-Pt(IV)@PEG-PAH-DMMA). The polymer endows the platform with high biocompatibility, initial nano-size for prolonged blood circulation and selective extravasation. Especially, the anionic polymer can response to the mild acidic stimulus (pH ∼6.5) of tumor extracellular microenvironment and experience charge-shifting to a cationic polymer, resulting in electrostatic repulsion and releases of positive UCNs-Pt(IV). The positive UCNs-Pt(IV) nanoparticles have high affinity to negative cell membrane, leading to efficacious cell internalization. Simultaneously, the ultraviolet (UV) light emitted from UCNs upon near-infrared (NIR) light irradiation, together with the reductive glutathione (GSH) in cancer cells efficiently activate the Pt(IV) prodrug to highly cytotoxic Pt(II), realizing NIR photon improved chemotherapy. The experimental results reveal the charge convertibility, low adverse effect and markedly enhanced tumor ablation efficacy upon NIR laser irradiation of this smart nanoplatform. Moreover, combining the inherent upconversion luminescence (UCL) and computed tomography (CT) imaging capabilities, an alliance of cancer diagnosis and therapy has been achieved.Download high-res image (340KB)Download full-size image
Co-reporter:Yan Wang;Guixin Yang;Yanli Wang;Yanping Zhao;Haizhi Jiang;Yuyan Han
Nanoscale (2009-Present) 2017 vol. 9(Issue 14) pp:4759-4769
Publication Date(Web):2017/04/06
DOI:10.1039/C6NR09030C
It is difficult to meet the requirements of clinical diagnosis through a single imaging technique. Similarly, satisfactory therapy efficacy is also hard to achieve by a single therapeutic modality. It is therefore highly desirable and interesting to simultaneously achieve multimodal imaging and therapies in one single structure. In this study, we developed a core–shell-satellite NaGdF4:Yb,Er,Mn,Co@mSiO2-CuS structure using up-conversion luminescent (UCL) NaGdF4:Yb,Er,Mn,Co as the core, mesoporous silica as the layer, and the photoactive CuS nanoparticles as the satellites. The further linked photosensitizer (ZnPc) and doxorubicin hydrochloride (DOX) allow the system to have photodynamic therapy (PDT) and chemotherapy functions. The doping of Co2+ ions in the core endows the carrier with T2-weighted magnetic resonance imaging (MRI) properties, and the co-doping of Mn2+ ions can efficiently enhance the red emission which further improves the PDT efficiency by reacting with the attached ZnPc upon near-infrared (NIR) light irradiation. The nanoplatform exhibits excellent anti-tumor efficiency due to a synergistic effect arising from combined PDT, photo-thermal therapy (PTT) and chemotherapy, which has been evidenced by in vitro and in vivo results. Due to the multimodal imaging (MRI, CT, and UCL) properties, the drug delivery process and therapeutic efficacy can be monitored in real time and assessed, thus achieving the target of imaging-guided therapy.
Co-reporter:Arif Gulzar;Jiating Xu;Fei He;Liangge Xu
Nanoscale (2009-Present) 2017 vol. 9(Issue 34) pp:12248-12282
Publication Date(Web):2017/08/31
DOI:10.1039/C7NR01836C
Lanthanide-doped photon upconverting nanomaterials are evolving as a new class of imaging contrast agents, offering highly promising prospects in the area of biomedical applications. Owing to their ability to convert long-wavelength near-infrared excitation radiation into shorter-wavelength emissions, these nanomaterials are well suited to yield properties of low imaging background, large anti-Stokes shift, along with high optical penetration depth of NIR light for deep tissue optical imaging or light-activated drug release and therapy. Such materials have potential for significant advantages in analytical applications compared to molecular fluorophores and quantum dots. The use of IR radiation as an excitation source diminishes autofluorescence and scattering of excitation radiation, which leads to a reduction of background in optical experiments. The upconverting nanocrystals show exceptional photostability and are constituted of materials that are not significantly toxic to biological organisms. Excitation at long wavelengths also minimizes damage to biological materials. In this detailed review, various mechanisms operating for the upconversion process, and methods that are utilized to synthesize and decorate upconverting nanoparticles are investigated to elucidate by what means absorption and emission can be tuned. Up-to-date reports concerning cellular internalization, biodistribution, excretion, cytotoxicity and in vivo toxic effects of UCNPs are discussed. Specifically, studies which assessed the relationship between the chemical and physical properties of UCNPs and their biodistribution, excretion, and toxic effects are reviewed in detail. Finally, we also deliberate the challenges of guaranteeing the biosafety of UCNPs in vivo.
Co-reporter:Yunlu Dai;Huiting Bi;Xiaoran Deng;Chunxia Li;Fei He;Ping'an Ma;Jun Lin
Journal of Materials Chemistry B 2017 vol. 5(Issue 11) pp:2086-2095
Publication Date(Web):2017/03/15
DOI:10.1039/C7TB00224F
The design of stimuli-responsive drug delivery systems has attracted much attention to improve therapeutic efficacy for clinical applications. Here an 808 nm NIR light responsive dual-drug system was designed for cancer treatment both in vitro and in vivo. Mesoporous silica coated NaYF4:Yb0.4/Tm0.02@NaGdF4:Yb0.1@NaNdF4:Yb0.1 (UCNPs) with a core-shell structure (labeled as UCNPs@mSiO2) was prepared and loaded with the antitumor drug doxorubicin (DOX). The surface of the composite was functionalized with β-cyclodextrin rings bridged by the light cleavable platinum(IV) pro-drug, thus blocking DOX inside the mesopores of silica. When excited by 808 nm NIR light, the emitted UV light from the UCNPs was used to activate the platinum(IV) pro-drug to gain higher toxicity platinum(II) complexes and open the mesopores of silica (at the same time) to release DOX molecules. Both DOX and platinum(II) complexes can kill cancer cells. This dual-drug delivery system may represent a new avenue for the application of UCNPs in photoactivated cancer therapy.
Co-reporter:Dan Yang;Guixin Yang;Jiaqi Li;Shili Gai;Fei He
Journal of Materials Chemistry B 2017 vol. 5(Issue 22) pp:4152-4161
Publication Date(Web):2017/06/07
DOI:10.1039/C7TB00688H
Two major issues of finding the appropriate photosensitizer and raising the penetration depth of irradiation light exist in further developing of photodynamic therapy (PDT). The excited ultraviolet/visible (UV/vis) irradiation light has a relatively shallow depth of penetration and UV light itself may have sufficient energy to damage normal tissues; these are substantial limitations to successful cancer therapy. Herein, we for the first time report a novel multifunctional nanoplatform for a single 980 nm near-infrared (NIR) light-triggered PDT based on NaGdF4:Yb,Tm@NaGdF4 upconversion nanoparticles (UCNPs) integrated with bismuth oxyhalide (BiOCl) sheets, designated as UCNPs@BiOCl. And UCNPs@BiOCl was fabricated by a convenient, efficient, green, and inexpensive method. Excitingly, layered bismuth oxyhalide materials possess a high photocatalytic performance, unique layered structures and wide light response to a broad wavelength range of ultraviolet to visible light. And the loaded UCNPs can convert NIR light into UV/vis region emissions, which drives the pure water splitting of BiOCl sheets to produce plenty of reactive oxygen species (ROS) to damage tumor cells. The excellent antitumor efficiency of the complex has been evidently attested by comparing experimental results. Our work may make a contribution to the wide application of BiOCl-based materials in biomedicine.
Co-reporter:Liangge Xu;Fei He;Chen Wang;Shili Gai;Arif Gulzar;Dan Yang;Chongna Zhong
Journal of Materials Chemistry B 2017 vol. 5(Issue 39) pp:7939-7948
Publication Date(Web):2017/10/11
DOI:10.1039/C7TB01983A
Low tissue penetration depth of the excited light and complicated synthetic procedures greatly hinder the clinical application of photodynamic therapy (PDT). Here we present a facile and mass production route to fabricate Yb3+/Tm3+ co-doped BiOBr nanosheets. In contrast to the complicated combination of photosensitizers (PSs) with up-conversion nanoparticles (UCNPs), which generates a PDT effect by a fluorescence resonance energy transfer process from UCNPs to PSs upon near-infrared light excitation, this as-synthesized material can be self-activated by deep-penetrating 980 nm laser light to produce a large amount of reactive oxygen species, giving rise to a high PDT efficiency which has been proven by in vitro and in vivo therapeutic assays. Surface modification of the BiOBr:Yb,Tm nanosheets with polyethylene glycol endows the system with improved biocompatibility. Through the combination of inherent fluorescence and CT imaging properties, an imaging-monitored therapeutic system has been realized. The system overcomes the problems of low tissue penetration depth, complicated structure-induced low efficiency, and potential safety concerns. Our finding presents the first demonstration of a self-activated nanoplatform for targeted and noninvasive deep-cancer therapy.
Co-reporter:Chen Wang;Liangge Xu;Jiating Xu;Dan Yang;Bin Liu;Shili Gai;Fei He
Dalton Transactions 2017 vol. 46(Issue 36) pp:12147-12157
Publication Date(Web):2017/09/19
DOI:10.1039/C7DT02791E
Core–shell nanostructures consisting of plasmonic materials and lanthanide-doped upconversion nanoparticles (UCNPs) show promising applications in theranostics including bio-imaging, diagnosis and therapy. However, some challenges still remain in the synthetic control because of the non-coordination between energy transfer and photothermal therapy (PTT). Herein, we developed a novel type of thermal-fluorescent core–shell hybrid nanocomposite incorporating rare-earth Yb3+ and Er3+ ion doped GdOF as the shell and gold nanorods (GNRs) as the core, creating upconversion nanorods (UCNRs) of GNRs@GdOF:Yb3+,Er3+. In order to facilitate the absorption or excretion of UCNRs in vivo, we designed gold nanorods with lower aspect ratios by reducing the amount of CTAB in the growth solution. More importantly, under 980 nm near-infrared (NIR) light irradiation, the green and red emissions of GdOF:Yb3+,Er3+ generally overlap with the visible absorbance of GNRs; by altering the contents of Yb3+ and Er3+ ions appropriately, the localized surface plasmon resonance (LSPR) absorption of low aspect ratio GNRs under 980 nm NIR laser excitation can be enhanced for improving the PTT efficiency. Furthermore, in vitro and in vivo assays reveal that the composite has excellent bio-compatibility and cancer therapy efficiency. This multi-functional nanocomposite, which possesses upconversion luminescence and photothermal and biocompatibility properties, shows strong potential for application in bio-imaging and photothermal anti-cancer therapy.
Co-reporter:Jiating Xu;Mingdi Sun;Ye Kuang;Huiting Bi;Bin Liu;Dan Yang;Ruichan Lv;Shili Gai;Fei He
Dalton Transactions 2017 vol. 46(Issue 5) pp:1495-1501
Publication Date(Web):2017/01/31
DOI:10.1039/C6DT04529D
Rare-earth-doped up-conversion nanoparticles (UCNPs), which are capable of converting infrared light to shorter-wavelength photons, have attracted worldwide attention due to their unique characteristics. However, the emission brightness of UCNPs is greatly limited by the unsatisfactory absorptivity of lanthanide ions. Herein, we adopted a novel strategy to enhance the up-conversion intensity using NIR dye IR-808 as an antenna to sensitize the core–shell–shell structured NaGdF4:Yb,Er@NaGdF4:Yb@NaNdF4:Yb UCNPs. When excited with 808 nm light, the IR-808 emitted a broadband peak, which perfectly overlapped with the absorption of Nd3+ and Yb3+ ions. Thus, the active shell of NaNdF4:Yb can efficiently capture the emitted NIR photons and transfer them to the transition layer of NaGdF4:Yb. The transition layer acted as an energy bridge to connect the active shell and up-converting zone, avoiding the energy back-transfer from the activators to Nd3+ ions. The optimized dye sensitization combined with the well-designed core–shell–shell structure tremendously enhances the NIR photon absorptivity of UCNPs and eliminates the deleterious cross-relaxation between the activators and sensitizers, eventually leading to dramatic enhancement of the up-conversion intensity. This study provides a new insight into the dye-sensitized up-conversion luminescence of rare earth-based nanoparticles and facilitates their practical applications.
Co-reporter:Lili Feng;Fei He;Yunlu Dai;Shili Gai;Chongna Zhong;Chunxia Li
Biomaterials Science (2013-Present) 2017 vol. 5(Issue 12) pp:2456-2467
Publication Date(Web):2017/11/21
DOI:10.1039/C7BM00798A
Photodynamic therapy (PDT) is a novel technique that has been extensively employed in cancer treatment; it utilizes reactive oxygen species to kill malignant cells. However, poor performance of the photosensitizer itself, limited penetration depth and the overexpression of glutathione (GSH) in cancer cells are the major obstacles facing the actual clinical application of PDT. Inspired by the challenges mentioned above, here we propose multifunctional nanoparticles utilizing mesoporous manganese silicate (MnSiO3)-coated upconversion nanoparticles (UCNPs) as nanocarriers for loading highly fluorescent graphitic-phase carbon nitride quantum dots (g-C3N4 QDs) to simultaneously act as a photosensitive drug and imaging agent. Surface modification of the nanoparticles with polyethylene glycol (PEG) endows the samples (denoted as UMCNs-PEG) with excellent biocompatibility and long-term in vivo circulation. Taking advantage of the inherent performance of the as-synthesized nanoparticles, multimodality imaging, including upconversion luminescence (UCL), computed tomography (CT) and magnetic resonance imaging (MRI), has been achieved; this is conducive to providing effective treatment information by real-time monitoring. In vivo photodynamic therapy to achieve effective tumor inhibition was then realized without inducing significant toxicity to treated mice. As a result, this work provides a novel paradigm with highly integrated functionalities which not only exhibits excellent prospects for imaging-guided photodynamic anticancer therapy but also encourages further exploration of new types of multifunctional nanoparticles for biomedical applications.
Co-reporter:Lili Feng, Shili Gai, Fei He, Yunlu Dai, Chongna Zhong, Piaoping Yang, Jun Lin
Biomaterials 2017 Volume 147(Volume 147) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.biomaterials.2017.09.011
Desirable nanosystem that could not only deliver drugs safely and effectively into tumor sites, but also be expected to serve as photosensitizer to realize the photodynamic therapeutic function, would be of great significance in the synergistic cancer therapy. To perform this task, a multifunctional nanosystem has been developed for markedly enhanced cancer therapeutic efficacy by loading chemotherapy agent (doxorubicin hydrochloride, DOX) and photosensitive drug chlorin e6 (Ce6) into the channels of mesoporous zirconium dioxide (ZrO2) layer which coats on Nd3+-doped upconversion nanoparticles (UCNPs). As a temperature sensitive phase change material (PCM), the loaded tetradecanol was served as switch for control release of DOX and reactive oxygen species (ROS) in the condition of enhanced temperature triggered by the near infrared (NIR) light irradiation. The hyperthermia generated from the UCNPs cores exposed to NIR laser could raise the temperature of tumor location to 47.8 °C. The as-synthesized UCNPs@ZrO2-Ce6/DOX/PCM nanosystem demonstrates an excellent in vivo synergistic effect by administrating into U14 tumor-bearing mice via intravenous injection, under mild NIR laser irradiation (0.5 W cm−2, 5 min break after 5 min irradiation). In a word, our experimental results indicate that the finely designed UCNPs@ZrO2-Ce6/DOX/PCM may act as an ideal nanoplatform for multiple imaging guided tumor therapy.
Co-reporter:Lili Feng, Fei He, Bin Liu, Guixin Yang, Shili Gai, Piaoping Yang, Chunxia Li, Yunlu Dai, Ruichan Lv, and Jun Lin
Chemistry of Materials 2016 Volume 28(Issue 21) pp:7935
Publication Date(Web):October 10, 2016
DOI:10.1021/acs.chemmater.6b03598
Exploring novel photosensitizer (PS) with good stability and high light converting efficiency and designing novel structure to integrate deep penetrating near-infrared (NIR) light excitable up-conversion nanoparticles (UCNPs) and PS into one system are highly fascinating in the photodynamic therapy (PDT) field. In this study, a novel core–shell structured platform (UCNPs@g-C3N4–PEG) with all-in-one “smart” functions for simultaneous photodynamic therapy, photothermal therapy (PTT), and trimodal imaging properties has been rationally designed and fabricated. This system is composed of a core–shell–shell structured NaGdF4:Yb/Tm@NaGdF4:Yb@NaNdF4:Yb up-conversion luminescence (UCL) core and photoactive graphitic-phase carbon nitride (g-C3N4) mesoporous shell closely coated on individual core. This designed structure allows large specific surface area, high loading amount, close proximity to the UCL core, and almost no leakage of g-C3N4 PS, thus ensuring sufficient reactive oxygen species (ROS) to damage tumor cells. Excitation by 808 nm NIR light, the emitted ultraviolet, and visible light can activate g-C3N4 to generate significant amount of ROS and the doped Nd3+ ions give rise to obvious thermal effect, which leads to excellent antitumor efficiency due to the combined PDT and PTT effect. Considering the trimodal imaging properties (UCL, computed tomography, and magnetic resonance imaging), we achieved an imaging guided cancer phototherapy motivated by a single NIR laser.
Co-reporter:Ruichan Lv, Dan Yang, Piaoping Yang, Jiating Xu, Fei He, Shili Gai, Chunxia Li, Yunlu Dai, Guixin Yang, and Jun Lin
Chemistry of Materials 2016 Volume 28(Issue 13) pp:4724
Publication Date(Web):June 15, 2016
DOI:10.1021/acs.chemmater.6b01720
A proper photosensitizer and increased penetration depth are still two major challenges in photodynamic therapy (PDT). The conventional ultraviolet/visible irradiation light has low tissue penetration, which thus limits its clinical application. Herein, we for the first time designed a novel multifunctional composite by integrating NaGdF4:Yb,Er@Yb@Nd@Yb upconversion nanoparticles (UCNPs) and black phosphorus sheets (BPS) for a single 808 nm laser light-mediated PDT. UCNPs, which served as the energy donor, were modified with poly(acrylic acid), and the BPS were stabilized by the PEG-NH2; then the two counterparts were integrated into the UCNPs–BPS composite via electrostatic interaction. Under 808 nm near-infrared light irradiation, the composite exhibits excellent antitumor efficiency because of the large amount of reactive oxygen species generated compared with those under 650 and 980 nm irradiations with the same pump power, which has evidently been confirmed by in vitro and in vivo results. In particular, our work may pave the way for the wide application of black phosphorus-based materials in theranostics.
Co-reporter:Jiating Xu, Ruichan Lv, Shaokang Du, Shili Gai, Fei He, Dan Yang and Piaoping Yang
Journal of Materials Chemistry A 2016 vol. 4(Issue 23) pp:4138-4146
Publication Date(Web):10 May 2016
DOI:10.1039/C6TB00714G
To enhance the total emission intensity, particularly the red emission of Yb,Er co-doped nanoparticles for red light activated photodynamic therapy (PDT), we doped Mn2+ ions into the NaGdF4:Yb,Er core, and subsequently coated the NaGdF4:Yb active shell to fabricate core–shell structured, up-conversion nanoparticles of NaGdF4:Yb,Er,Mn@NaGdF4:Yb (abbreviated as UCNPs). A novel and facile encapsulation method with gelatin has been proposed to transfer oleic acid (OA) stabilized UCNPs into an aqueous solution and simultaneously decorate zinc phthalocyanine (ZnPc) photosensitizer molecules. In the encapsulation process, ZnPc molecules are wrapped in the interlaced net structure of the peptide chain from gelatin, forming the UCNPs@gel–ZnPc nanocomposite. The nanoplatform has high emission intensity and excellent biocompatibility, as was expected. More importantly, the enhanced red emission of UCNPs has significant overlap with the UV absorbance of ZnPc; therefore, it can effectively activate the sensitizer to produce a large amount of singlet oxygen reactive oxygen species (ROS, 1O2) to kill cancer cells, which has evidently been verified by the in vitro results. Combined with the inherent up-conversion luminescence (UCL) imaging properties, this UCNPs@gel–ZnPc nanoplatform could have potential application in PDT and imaging fields.
Co-reporter:Shuchao Sun, Peng Gao, Yurong Yang, Piaoping Yang, Yujin Chen, and Yanbo Wang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 28) pp:18126-18131
Publication Date(Web):June 29, 2016
DOI:10.1021/acsami.6b05244
To narrow the band gap (3.2 eV) of TiO2 and extend its practical applicability under sunlight, the doping with nonmetal elements has been used to tune TiO2 electronic structure. However, the doping also brings new recombination centers among the photoinduced charge carriers, which results in a quantum efficiency loss accordingly. It has been proved that the {101} facets of anatase TiO2 are beneficial to generating and transmitting more reductive electrons to promote the H2-evolution in the photoreduction reaction, and the {001} facets exhibit a higher photoreactivity to accelerate the reaction involved of photogenerated hole. Thus, it was considered by us that using the surface heterojunction composed of both {001} and {101} facets may depress the disadvantage of N doping. Fortunately, we successfully synthesized anatase N-doped TiO2 nanobelts with a surface heterojunction of coexposed (101) and (001) facets. As expected, it realized the charge pairs’ spatial separation and showed higher photocatalytic activity under a visible-light ray: a hydrogen generation rate of 670 μmol h–1 g–1 (much higher than others reported previously in literature of N-doped TiO2 nanobelts).
Co-reporter:Huiting Bi, Yunlu Dai, Ruichan Lv, Chongna Zhong, Fei He, Shili Gai, Arif Gulzar, Guixin Yang and Piaoping Yang
Dalton Transactions 2016 vol. 45(Issue 12) pp:5101-5110
Publication Date(Web):29 Jan 2016
DOI:10.1039/C5DT04842G
To integrate photothermal therapy (PTT) with chemotherapy for improving anticancer efficiency, we developed a novel and multifunctional doxorubicin (DOX) conjugated copper sulfide nanoparticle (CuS–DOX NP) drug delivery system using hydrazone bonds to conjugate carboxyl-functionalized copper sulfide nanoparticles (CuS NPs) and DOX. On the other hand, the hydrazone bonds could be used for improving the DOX release rate (88.0%) by cleavage in a mildly acidic environment irradiated by 808 nm laser light, which could greatly promote chemo-therapeutic efficacy. Simultaneously, CuS NPs which can absorb near infrared (NIR) light produce a clear thermal effect, giving rise to a synergistic therapeutic effect combined with enhanced chemo-therapy. The DOX-conjugated CuS NPs display an evident in vitro cytotoxicity to HeLa cancer cells under 808 nm light irradiation. High tumor inhibition efficacy has been achieved after 14 day in vivo treatment, performed with intravenous administration of CuS–DOX NPs with 808 nm laser irradiation on H22 tumor-bearing mice. The multifunctional system which was achieved by a facile route should be a potential candidate in the anti-cancer field due to the synergistic therapeutic effect, which is superior to any single approach.
Co-reporter:Ruichan Lv, Chongna Zhong, Arif Kuhan Gulzar, Fei He, Rui Gu, Shili Gai, Shenghuan Zhang, Guixin Yang and Piaoping Yang
RSC Advances 2016 vol. 6(Issue 26) pp:21590-21599
Publication Date(Web):18 Feb 2016
DOI:10.1039/C6RA00668J
To combine photodynamic therapy (PDT) and bio-imaging for improved antitumor efficacy, we design a yolk-like NaYF4:Yb,Er@MgSiO3–ZnPc–RGD mesoporous platform by encapsulating a photosensitive agent (ZnPc) and a targeted peptide, NH2-Gly-Arg-Gly-Asp-Ser (RGD), into MgSiO3 mesoporous shell coated NaYF4:Yb,Er spheres. A novel spinous MgSiO3 shell is synthesized by an in situ growth process without using any surfactant, instead of the conventional mesoporous silica shell. Upon 980 nm laser irradiation, the emitted red light matches well with the absorbance of ZnPc, which generates reactive oxygen species (ROS) to kill cancer cells, and the retained green light allows for real-time monitoring of the therapeutic process. The in vitro and in vivo results indicate that the platform shows excellent anti-cancer therapeutic efficacy under NIR laser irradiation due to the specialised intracellular transition pattern, avoiding premature leakout of ZnPc, and targeted accumulation in the cancer cell sites. Thus, we envision that our proposed platform should have great potential for PDT-induced tumor therapy and for monitoring biochemical changes taking place in live tumor cells.
Co-reporter:Di Bao;Peng Gao;Chenliang Li;Guoxun Wu;Yanbo Wang;Yujin Chen;Han Zhou
European Journal of Inorganic Chemistry 2016 Volume 2016( Issue 21) pp:3371-3375
Publication Date(Web):
DOI:10.1002/ejic.201600345
Co2P nanoparticles, obtained by a simple mechanical ball-milling treatment, have been shown to undergo a new hydrogen adsorption–transmission process called intracell Kubas-enhanced adsorption, which results in an improved hydrogen-storage capacity. It is found that in this intracell Kubas-enhanced adsorption process hydrogen is firstly adsorbed by the Co atoms in Co2P through a Co···H interaction and activated. It is then spilt over to the P atoms in Co2P accompanied by the formation of a P–H bond, which has a lower bonding energy. This adsorption–transmission process is unambiguously proved by a detailed analysis of X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), cyclic voltammetry (CV), and quantum chemical calculation results.
Co-reporter:Tao Feng, Xiangzhao Ai, Guanghui An, Piaoping Yang, and Yanli Zhao
ACS Nano 2016 Volume 10(Issue 4) pp:4410
Publication Date(Web):March 20, 2016
DOI:10.1021/acsnano.6b00043
Carbon dots (CDs) are remarkable nanocarriers due to their promising optical and biocompatible capabilities. However, their practical applicability in cancer therapeutics is limited by their insensitive surface properties to complicated tumor microenvironment in vivo. Herein, a tumor extracellular microenvironment-responsive drug nanocarrier based on cisplatin(IV) prodrug-loaded charge-convertible CDs (CDs–Pt(IV)@PEG-(PAH/DMMA)) was developed for imaging-guided drug delivery. An anionic polymer with dimethylmaleic acid (PEG-(PAH/DMMA)) on the fabricated CDs–Pt(IV)@PEG-(PAH/DMMA) could undergo intriguing charge conversion to a cationic polymer in mildly acidic tumor extracellular microenvironment (pH ∼ 6.8), leading to strong electrostatic repulsion and release of positive CDs–Pt(IV). Importantly, positively charged nanocarrier displays high affinity to negatively charged cancer cell membrane, which results in enhanced internalization and effective activation of cisplatin(IV) prodrug in the reductive cytosol. The in vitro experimental results confirmed that this promising charge-convertible nanocarrier possesses better therapeutic efficiency under tumor extracellular microenvironment than normal physiological condition and noncharge-convertible nanocarrier. The in vivo experiments further demonstrated high tumor-inhibition efficacy and low side effects of the charge-convertible CDs, proving its capability as a smart drug nanocarrier with enhanced therapeutic effects. The present work provides a strategy to promote potential clinical application of CDs in the cancer treatment.Keywords: cancer therapy; carbon dots; charge convertibility; imaging guiding; in vivo studies
Co-reporter:Dan Yang, Guixin Yang, Shili Gai, Fei He, Ruichan Lv, Yunlu Dai, and Piaoping Yang
ACS Biomaterials Science & Engineering 2016 Volume 2(Issue 11) pp:2058
Publication Date(Web):September 29, 2016
DOI:10.1021/acsbiomaterials.6b00462
Exploring a combined anticancer therapeutic strategy to overcome the limitations of a single mode and pursue higher therapeutic efficiency is highly promising in both fundamental and clinical investigations. Herein, a theranostic nanoplatform based on mesoporous silica, which is functionalized by hybrid nanosphere photosensitizer Chlorin e6 (Ce6), photothermal agent carbon dots (CDs), and imaging agent Gd (III) ions has been rationally designed and fabricated. A thermo/pH-coupling sensitive polymer (P(NIPAm-co-MAA)) coated on a composite acted as a key “gatekeeper” to control drug release at the appropriate time and location. Upon light irradiation, two-mode synergistic therapeutic effect of photodynamic and photothermal therapy can be achieved by photoactive Ce6 and CDs. Meanwhile, the CDs loaded in the channels of mesoporous silica hybrid spheres can also play a role in handling the “gatekeeper” polymer to control the drug release process. Combined with the thermo/pH-sensitive drug release-induced controllable chemotherapy, this platform shows synergistic therapeutic efficacy better than any single/dual therapy, which is confirmed with evidence from in vivo and in vitro assays. Considering the chelated Gd3+ simultaneously introduced magnetic resonance imaging (MRI) and computed tomography (CT) properties, this multifunctional platform should have excellent potential in the imaging-guided cancer therapy field.Keywords: cancer; imaging; photodynamic therapy; photothermal therapy; silica
Co-reporter:Fei He;Guixin Yang;Yuxiu Yu;Ruichan Lv;Chunxia Li;Yunlu Dai;Shili Gai;Jun Lin
Advanced Functional Materials 2015 Volume 25( Issue 25) pp:3966-3976
Publication Date(Web):
DOI:10.1002/adfm.201500464
The NIR light-induced imaging-guided cancer therapy is a promising route in the targeting cancer therapy field. However, up to now, the existing single-modality light-induced imaging effects are not enough to meet the higher diagnosis requirement. Thus, the multifunctional cancer therapy platform with multimode light-induced imaging effects is highly desirable. In this work, captopril stabilized-Au nanoclusters Au25(Capt)18−(Au25) are assembled into the mesoporous silica shell coating outside of Nd3+-sensitized upconversion nanoparticles (UCNPs) for the first time. The newly formed Au25 shell exhibits considerable photothermal effects, bringing about the photothermal imaging and photoacoustic imaging properties, which couple with the upconversion luminescence imaging. More importantly, the three light-induced imaging effects can be simultaneously achieved by exciting with a single NIR light (808 nm), which is also the triggering factor for the photothermal and photodynamic cancer therapy. Besides, the nanoparticles can also present the magnetic resonance and computer tomography imaging effects due to the Gd3+ and Yb3+ ions in the UCNPs. Furthermore, due to the photodynamic and the photothermal effects, the nanoparticles possess efficient in vivo tumor growth inhibition under the single irradiation of 808 nm light. The multifunctional cancer therapy platform with multimode imaging effects realizes a true sense of light-induced imaging-guided cancer therapy.
Co-reporter:Ruichan Lv, Chongna Zhong, Rumin Li, Piaoping Yang, Fei He, Shili Gai, Zhiyao Hou, Guixin Yang, and Jun Lin
Chemistry of Materials 2015 Volume 27(Issue 5) pp:1751
Publication Date(Web):February 9, 2015
DOI:10.1021/cm504566f
As a potential photosensitizer for photodynamic therapy (PDT), pure titanium dioxide has the drawbacks of low tissue penetration and possible damage to skin due to the triggered UV light. To realize near-infrared (NIR) laser-induced multimodal imaging guided therapy, we constructed a multifunctional core–shell structure (TiO2@Y2Ti2O7@YOF:Yb,Tm) by a facile coprecipitation route, followed by an annealing process. Under a single NIR laser irradiation, the highly cytotoxic reactive oxygen species (ROS) required for PDT can be generated due to the energy transfer from YOF:Yb,Tm to the Y2Ti2O7 photocatalyst which is responsive to blue emission (visible light), and the thermal effect can be simultaneously produced due to the nonradiative transition and the recombination of electron–hole pairs. The NIR light induced PDT and photothermal therapy (PTT) can efficiently suppress tumor growth, which was evidenced by both in vitro and in vivo results. Moreover, the rare earth ions in the composite make the material have good up-conversion luminescence (UCL) imaging and CT imaging properties, thus achieving the target of synergistic PDT and PTT therapy under the multimodal imaging guidance.
Co-reporter:Xiaoming Zhou, Peng Gao, Shuchao Sun, Di Bao, Ying Wang, Xiaobo Li, Tingting Wu, Yujin Chen, and Piaoping Yang
Chemistry of Materials 2015 Volume 27(Issue 19) pp:6730
Publication Date(Web):September 22, 2015
DOI:10.1021/acs.chemmater.5b02753
Selenium is applied as the cathode material of lithium/selenium (Li–Se) battery, which has high theoretical volumetric capacity density (3253 mA h·cm–3) and high output voltages. However, it has a low melting point (494 K) and a large sensitivity to thermal treatment, which often result in the phase transition between crystalline Se (trigonal phase) and amorphous Se during the charge/discharge cycles of Li–Se battery as reported in literatures. In order to clarify the different chemical (de)lithiation mechanisms between them in Li–Se battery, in this work large-area amorphous selenium (a-Se) nanowires (NWs) have been successfully prepared first through a facile high-energy ball-milling method. Subsequently the crystalline (c) and crystalline/amorphous (c/a) selenium NWs have also been prepared through annealing the above as-obtained amorphous products, respectively. The affirmative composition and morphology of the as-obtained Se nanostructures have been demonstrated by the XRD, SEM, TEM, HRTEM and Raman spectra measurements. And their specific surface area and pore size distribution have also been analyzed by BET measurements. Finally, it is proved that the as-obtained NWs used as the cathode material of Li–Se battery displayed different chemical reaction processes with Li+ and the related various storage capacities (a-Se: 755 mAh·g–1; c/a-Se: 705 mAh·g–1; c-Se: 250 mAh·g–1). This work has helped us to better understand and correlate the formation of intermediate phases with the electrochemical performance of Li–Se cells and shines new light on how to improve the cell performance by turning the phase of Se.
Co-reporter:Guixin Yang, Dan Yang, Piaoping Yang, Ruichan Lv, Chunxia Li, Chongna Zhong, Fei He, Shili Gai, and Jun Lin
Chemistry of Materials 2015 Volume 27(Issue 23) pp:7957
Publication Date(Web):November 12, 2015
DOI:10.1021/acs.chemmater.5b03136
To solve the issue of limited penetration depth and overheating of the excited 980 nm near-infrared (NIR) light, and unstable and insufficient loading amount of photosensitizers (PSs) in photodynamic therapy (PDT), we have constructed a well-defined core–shell structured NaGdF4:Yb/Tm@NaGdF4:Yb@NaNdF4:Yb@NaGdF4@mSiO2@TiO2 (UCNPs@mSiO2@TiO2) nanocomposite by coating a layer of TiO2 PSs/photocatalyst on an effective 808 nm-to-UV/visible upconversion luminescent (UCL) core to achieve simultaneous multiple bioimaging and efficient PDT. The design of quenching-shield layer can eliminate the back energy transfer from activator Tm3+ to sensitized Nd3+, thus significantly improving the UCL emission. The high surface area of mesoporous silica-coated UCNPs facilitates the stable and high loading amount of anatase TiO2. In vivo results indicate that 808 nm NIR light-mediated PDT using UCNPs@mSiO2@TiO2 as photosensitizers shows much higher antitumor efficacy than those with 980 nm and UV irradiations due to the higher tissue penetration depth. Meanwhile, the platform itself as an imaging nanoprobe endows the sample with multiple imaging (UCL/CT/MRI) properties. Our work makes great progress toward the integrity of diagnosis and PDT induced by a single 808 nm NIR light.
Co-reporter:Ruichan Lv, Piaoping Yang, Fei He, Shili Gai, Guixin Yang, and Jun Lin
Chemistry of Materials 2015 Volume 27(Issue 2) pp:483
Publication Date(Web):December 9, 2014
DOI:10.1021/cm503647k
To integrate photothermal therapy (PTT) with chemotherapy for improved antitumor efficiency, we designed a novel multifunctional composite by attaching CuxS nanoparticles onto the surface of Y2O3:Yb/Er hollow spheres through a combined coprecipitation and subsequent hydrothermal route. By altering the initial pH values for the synthesis of precursors, the size and structure properties of the final composites can controllably be tuned. The conjugated folic acid (FA) makes the composite recognize the targeted cancer cells and the attached CuxS nanoparticles endow the composite with photothermal function. It is found that the release of doxorubicin (DOX) from the functional carrier could be triggered by both pH value and near-infrared (NIR) radiation. In particular, both PTT and chemotherapy can be simultaneously driven by 980 nm laser irradiation. The synergistic therapeutic effect based on PTT and chemotherapy can lead to low in vitro viability of 12.9% and highly strong inhibition of animal H22 tumor in vivo, which is superior to any individual therapy. Moreover, the composite exhibits the clear in vivo red up-conversion luminescence (UCL). This multifunctional nanocarrier can be applicable as bioimaging agent and effective antitumor agent for the synergistic interaction between PTT and the enhanced chemotherapy.
Co-reporter:Arif Gulzar, Shili Gai, Piaoping Yang, Chunxia Li, Mohd Bismillah Ansari and Jun Lin
Journal of Materials Chemistry A 2015 vol. 3(Issue 44) pp:8599-8622
Publication Date(Web):03 Sep 2015
DOI:10.1039/C5TB00757G
In the last decade, using polymer and mesoporous silica materials as efficient drug delivery carriers has attracted great attention. Although the development and application of them involves some inevitable barriers, such as chronic toxicities, long-term stability, understanding of the biological fate and physiochemical properties, biodistribution, effect in the biological environment, circulation properties and targeting efficacy in vivo. The construction of stimuli responsive drug carriers using biologically safe materials, followed by hydrophilic modification, bioconjugation, targeting functionalization, and detailed safety analysis in small/large animal models may be the best way to overcome these barriers. Huge progress has been made in stimuli responsive drug delivery systems based on polymer and mesoporous silica materials, mainly including pH-, thermo-, light-, enzyme-, redox-, magnetic field- and ultrasound-responsive drug delivery systems, all of which are highlighted in this review.
Co-reporter:Lei Li, Rumin Li, Shili Gai, Peng Gao, Fei He, Milin Zhang, Yujin Chen and Piaoping Yang
Journal of Materials Chemistry A 2015 vol. 3(Issue 30) pp:15642-15649
Publication Date(Web):23 Jun 2015
DOI:10.1039/C5TA03224E
In this contribution, we present a novel and rational strategy for preparing hierarchical porous CNTs@NCS@MnO2 core–shell composites via a facile in situ chemical polymerization coating method, followed by a hydrothermal process. An intermediate nitrogen-doped carbon shell (NCS) with mesoporous structure and favorable chemical durability is obtained by utilizing resorcinol–formaldehyde resin as the carbon source and L-cysteine as the nitrogen source. Benefiting from a unique structure and considerable combination, the composites exhibit a highly comprehensive electrochemical performance: high specific capacitance (312.5 F g−1 at a current density of 1 A g−1), good rate capability (76.8% retention with the charge–discharge rate increasing from 1 A g−1 to 10 A g−1), superior reversibility and cycling stability (92.7% capacitance retention after 4000 cycles at 8 A g−1). In order to increase the energy density and voltage window, an asymmetric supercapacitor (ASC) was assembled using CNTs@NCS@MnO2 and activated carbon (AC) as the positive and negative electrodes, respectively. The as-fabricated asymmetric supercapacitor achieved a high specific capacitance with a stable operating voltage of 1.8 V and a maximum energy density of 27.3 W h kg−1. Such a synthetic route to prepare capacitor materials can thoroughly motivate the synergistic effect between electrical double layer capacitors and pseudocapacitors for obtaining high comprehensive performance electrodes in energy storage fields.
Co-reporter:Huanming Zhang, Chunling Zhu, Yujin Chen, Min Yang, Piaoping Yang, Xiaohong Wu, Lihong Qi and Fanna Meng
Journal of Materials Chemistry A 2015 vol. 3(Issue 4) pp:1421-1426
Publication Date(Web):27 Nov 2014
DOI:10.1039/C4TA05171H
A facile strategy was developed to fabricate net-like hematite nanoparticle/graphene oxide (GO) composite (NHG), in which the degree of oxidization of GO could be controlled by simply changing annealing time. NHG with GO of appropriate oxidization degree and content exhibited much higher photocatalytic activities than α-Fe2O3 nanorods and commercial α-Fe2O3.
Co-reporter:Dan Yang, Guixin Yang, Shili Gai, Fei He, Guanghui An, Yunlu Dai, Ruichan Lv and Piaoping Yang
Nanoscale 2015 vol. 7(Issue 46) pp:19568-19578
Publication Date(Web):29 Oct 2015
DOI:10.1039/C5NR06192J
Near-infrared (NIR) light-induced cancer therapy has gained considerable interest, but pure inorganic anti-cancer platforms usually suffer from degradation issues. Here, we designed metal–organic frameworks (MOFs) of Fe3O4/ZIF-8-Au25 (IZA) nanospheres through a green and economic procedure. The encapsulated Fe3O4 nanocrystals not only produce hyperthemal effects upon NIR light irradiation to effectively kill tumor cells, but also present targeting and MRI imaging capability. More importantly, the attached ultrasmall Au25(SR)18− clusters (about 2.5 nm) produce highly reactive singlet oxygen (1O2) to cause photodynamic effects through direct sensitization under NIR light irradiation. Furthermore, the Au25(SR)18− clusters also give a hand to the hyperthemal effect as photothermal fortifiers. This nanoplatform exhibits high biocompatibility and an enhanced synergistic therapeutic effect superior to any single therapy, as verified by in vitro and in vivo assay. This image-guided therapy based on a metal–organic framework may stimulate interest in developing other kinds of metal–organic materials with multifunctionality for tumor diagnosis and therapy.
Co-reporter:Guixin Yang, Ruichan Lv, Fei He, Fengyu Qu, Shili Gai, Shaokang Du, Zibo Wei and Piaoping Yang
Nanoscale 2015 vol. 7(Issue 32) pp:13747-13758
Publication Date(Web):10 Jul 2015
DOI:10.1039/C5NR03085D
In this contribution, a novel multifunctional anti-cancer nanoplatform has been firstly constructed by conjugating a photothermal agent (CuS nanoparticles) and a cancer cell target agent (folic acid, FA) onto the surface of mesoporous silica coated core–shell–shell up-conversion nanoparticles (UCNPs). It was found that the doxorubicin (DOX) loaded system exhibits obvious pH and NIR-responsive release behaviour and the drug can be targetedly delivered to the cancer cells by a receptor mediated endocytosis manner. Furthermore, both photothermal therapy (PTT) and chemotherapy can be triggered simultaneously by a single 808 nm near infrared (NIR) light source, thus leading to a synergistic effect. The combined chemo- and NIR photothermal therapy can significantly improve the therapeutic efficacy compared to any single therapy, which has been evidenced by both in vitro and in vivo results. Besides, due to the doped rare earth ions, the platform also exhibits good up-conversion luminescence (UCL), computed tomography (CT) and magnetic resonance imaging (MRI) properties. Based on the excellent multimodal imaging and anti-tumor properties, the multifunctional nanoplatform should be a promising candidate for imaging-guided anti-cancer therapy.
Co-reporter:Dan Yang, Guixin Yang, Xingmei Wang, Ruichan Lv, Shili Gai, Fei He, Arif Gulzar and Piaoping Yang
Nanoscale 2015 vol. 7(Issue 28) pp:12180-12191
Publication Date(Web):15 Jun 2015
DOI:10.1039/C5NR02269J
Multifunctional composites have gained significant interest due to their unique properties which show potential in biological imaging and therapeutics. However, the design of an efficient combination of multiple diagnostic and therapeutic modes is still a challenge. In this contribution, Y2O3:Yb,Er@mSiO2 double-shelled hollow spheres (DSHSs) with up-conversion fluorescence have been successfully prepared through a facile integrated sacrifice template method, followed by a calcination process. It is found that the double-shelled structure with large specific surface area and uniform shape is composed of an inner shell of luminescent Y2O3:Yb,Er and an outer mesoporous silica shell. Ultra small CuxS nanoparticles (about 2.5 nm) served as photothermal agents, and a chemotherapeutic agent (doxorubicin, DOX) was then attached onto the surface of mesoporous silica, forming a DOX–DSHS–CuxS composite. The composite exhibits high anti-cancer efficacy due to the synergistic photothermal therapy (PTT) induced by the attached CuxS nanoparticles and the enhanced chemotherapy promoted by the heat from the CuxS-based PTT when irradiated by 980 nm near-infrared (NIR) light. Moreover, the composite shows excellent in vitro and in vivo X-ray computed tomography (CT) and up-conversion fluorescence (UCL) imaging properties owing to the doped rare earth ions, thus making it possible to achieve the target of imaging-guided synergistic therapy.
Co-reporter:Qiang Zhang, Lei Li, Yanli Wang, Yujin Chen, Fei He, Shili Gai, Piaoping Yang
Electrochimica Acta 2015 Volume 176() pp:542-547
Publication Date(Web):10 September 2015
DOI:10.1016/j.electacta.2015.06.154
Uniform fibrous-structured hollow mesoporous carbon spheres (FHMCSs) have been synthesized by a simple template method using fibrous-structured mesoporous silica microspheres and resol precursor as silica template and carbon sources, respectively. It is found that FHMCSs have an ultra high specific surface area of 1121 m2 g−1 and large pore volume of 1.3 cm3 g−1. The high surface-to-volume ratio is a favorable factor to obtain high specific capacitance and excellent rate performance. As expected, when used as supercapacitor electrodes, the FHMCSs exhibit high specific capacitance of 359.2 F g−1 at current density of 1 A g−1 and excellent cycle stability (92% retention after 5000 cycles). The energy density of the FHMCSs can be estimated to be 49.9 Wh kg−1 at a power density of 500 Wh kg−1. Moreover, the FHMCSs electrode shows high energy density of 36.4 Wh kg−1 even at the power density of 10000 W kg−1, suggesting a potential application in supercapacitors and other energy storage fields.
Co-reporter:Jie Xu, Lei Li, Peng Gao, Lei Yu, Yujin Chen, Ping Yang, Shili Gai, Piaoping Yang
Electrochimica Acta 2015 Volume 166() pp:206-214
Publication Date(Web):1 June 2015
DOI:10.1016/j.electacta.2015.03.093
A hybrid composite containing ultrathin NiCo2O4 nanobelts and graphene nanosheets was prepared through a simple and scalable hydrothermal method combined with suitable heat treatment. The optimal calcination condition has been optimized by investigating the pseudocapacitive behaviour of bare spinel NiCo2O4 prepared at different calcination temperatures. It is found that the self-assembled microstructure of NiCo2O4 nanobelts prepared at 250 °C (named as S250) exhibit superior electrochemical performance to those prepared at other temperatures. The composite comprising NiCo2O4 nanobelts and graphene nanosheets (GS250) has enlarged specific surface area (222 m2/g), yielding a high specific capacitance of 1072.91 F/g at the current density of 1 A/g with desirable rate performance and cycling stability. In view of simple, high-yield synthetic route and remarkable electrochemical properties, this NiCo2O4 nanobelt/graphene hybrid composite should be a promising electrode material for supercapacitors in high energy density storage systems.A hybrid composite containing one-dimensional NiCo2O4 nanobelt and graphene nanosheets was prepared through a facile hydrothermal process followed by a suitable heat treatment, which shows improved rate capability and high cycle stability.
Co-reporter:Guixin Yang, Fei He, Ruichan Lv, Shili Gai, Ziyong Cheng, Yunlu Dai and Piaoping Yang
Dalton Transactions 2015 vol. 44(Issue 1) pp:247-253
Publication Date(Web):17 Oct 2014
DOI:10.1039/C4DT02425G
A facile solution-based thermal decomposition strategy, using very cheap polyisobutylene succimide (PIBSI) and paraffin oil as a surfactant and solvent, respectively, has been developed for the controllable synthesis of magnetic MnFe2O4 and CoFe2O4 nanocrystals (NCs) with high dispersibility, uniform shape, and high yield. By fine-tuning the reaction temperature and growth time, the morphology and size of MnFe2O4 and CoFe2O4 NCs can be simply regulated. It is found that the surfactant PIBSI plays a key role in the final shape of the products due to its long chain with non-polar groups, which can markedly hinder the aggregation of the NCs and thus greatly improve the stability and dispersibility of the products. The results reveal that MnFe2O4 and CoFe2O4 NCs have good biocompatibility and obvious T2 contrast enhancement effects have been achieved with the increase of iron concentration. MnFe2O4 and CoFe2O4 NCs show high longitudinal relaxivity of 165.6 and 65.143 mM−1 S−1 in aqueous solutions due to the positive signal enhancement ability of Fe3+ ions, indicating the highly potential to be used as effective T2 contrast agents for magnetic resonance imaging (MRI).
Co-reporter:Ruichan Lv, Chongna Zhong, Arif Gulzar, Shili Gai, Fei He, Rui Gu, Shenghuan Zhang, Guixin Yang and Piaoping Yang
Dalton Transactions 2015 vol. 44(Issue 42) pp:18585-18595
Publication Date(Web):28 Sep 2015
DOI:10.1039/C5DT03604F
In this report, MgSiO3:Eu-DOX-DPP-RGD hollow microspheres employed for simultaneous imaging and anti-cancer therapy have been designed by sequentially loading the anti-tumor drugs doxorubicin (DOX), light-activated platinum(IV) pro-drug PPD, and a targeted peptide of NH2-Gly-Arg-Gly-Asp-Ser (RGD) onto MgSiO3:Eu mesoporous hollow spheres, which were synthesized using solid SiO2 spheres as sacrificed template by a facile hydrothermal process based on the Kirkendall effect. The photoluminescence intensity of MgSiO3:Eu has been optimized, which can emit a recognized red signal in vitro and in vivo under modest ultraviolet (UV) irradiation. It was found that the platform has high biocompatibility and could become intracellular through fast and effective endocytosis with the aid of the targeted peptide RGD, and chemotherapeutic drugs DOX and light-activated platinum(IV) pro-drug DPP that can be released from the carrier to induce an obvious inhabitation effect to HeLa cancer cells (survival rate of only 17.4%), which has been verified by in vitro and in vivo results. Moreover, the in vitro result using a photosensitizer ZnPc loaded carrier shows that the system is not suitable for ZnPc induced photodynamic therapy. The apparent imaging effect and high anti-tumor efficacy of this functional system give it great potential in actual clinical applications.
Co-reporter:Weicheng Pan, Shenghuan Zhang, Fei He, Shili Gai, Yanbo Sun and Piaoping Yang
CrystEngComm 2015 vol. 17(Issue 30) pp:5744-5750
Publication Date(Web):23 Jun 2015
DOI:10.1039/C5CE00678C
Ferromagnetic nanoparticles (NPs) prepared by conventional routes usually lead to large particle sizes because of their easy aggregation nature, and the low loading amount greatly limits their application in reduction of 4-nitrophenol (4-NP). In this contribution, well dispersed Ni nanoparticles with small diameter of 7 nm are supported on mesoporous silica SBA-15 through a facile in situ decomposition and reduction strategy. It is found that the as-prepared Ni/SBA-15 can be used as a catalyst and exhibits a high specific surface area (461 m2 g−1) and ultra-high loading amount of Ni particles (574 μg mg−1). The well-dispersed and high-loading Ni NPs make the Ni/SBA-15 exhibit excellent catalytic performance in 4-NP reduction, superior to any Ni NPs supported catalysts reported so far and many noble metal supported catalysts. In particular, the magnetic behaviour of Ni/SBA-15 makes it easy to recycle for reuse. This novel synthetic strategy may pave the way for the preparation of other metal nanoparticles supported on different kinds of amorphous silica with high loading capacity and high dispersion.
Co-reporter:Ruichan Lv, Guixin Yang, Fei He, Yunlu Dai, Shili Gai and Piaoping Yang
RSC Advances 2015 vol. 5(Issue 54) pp:43391-43401
Publication Date(Web):10 Apr 2015
DOI:10.1039/C5RA05437K
In this report, mesoporous NaYF4:Yb,Er@Au–Pt(IV)-FA up-conversion nanoparticles (UCNPs) have been designed by attaching Au NPs and Pt(IV) pro-drugs on the surface of PEI hydrogel modified mesoporous NaYF4:Yb,Er nanospheres. Finally the molecules modified with folic acid (FA) improve the receptor-mediated endocytosis. Because of the doped rare earth ions in the host matrix, the as-synthesized platform exhibits excellent up-conversion luminescence (UCL) imaging and computed X-ray tomography (CT) imaging properties. Diverse methods including MTT assay, hemolysis experiments, and live/dead cell analysis were employed to evaluate the biocompatibility and ablation efficacy of the as-synthesized platform. It was found that the cytotoxicity of the platform can be tuned by eliminating the axial ligands reductively during intracellular endocytosis. Especially, under 980 nm near-infrared (NIR) irradiation, the platform shows excellent inhibition toward cancer cells due to the synergistic photothermal injury to enzymes and membrane integrity combined with the DNA binding of activated Pt(II) to avoid cell proliferation. The developed nanocomposite may thus be a promising imaging-guided synergistic anti-cancer platform.
Co-reporter:Ruichan Lv, Piaoping Yang, Fei He, Shili Gai, Chunxia Li, Yunlu Dai, Guixin Yang, and Jun Lin
ACS Nano 2015 Volume 9(Issue 2) pp:1630
Publication Date(Web):January 12, 2015
DOI:10.1021/nn5063613
To integrate photodynamic therapy (PDT) with photothermal therapy (PTT) and chemotherapy for enhanced antitumor efficiency, we developed a mild and rational route to synthesize novel multifunctional GdOF:Ln@SiO2 (Ln = 10%Yb/1%Er/4%Mn) mesoporous capsules using strong up-conversion luminescent (UCL) GdOF:Ln as cores and mesoporous silica layer as shells, followed by modification with varied functional groups onto the framework. It was found that due to the codoped Yb/Er/Mn in GdOF, the markedly enhanced red emission can efficiently transfer energy to the conjugated PDT agent (ZnPc) which produces high singlet oxygen, and the incorporated carbon dots outside the shell can generate obvious thermal effect under 980 nm laser irradiation and also prevent the premature leaking of ZnPc. Simultaneously, the as-produced thermal effect can obviously enhance the doxorubicin (DOX) release, which greatly improves the chemotherapy, resulting in a synergistic therapeutic effect. The system exhibits drastically enhanced therapeutic efficiency against tumor growth, as demonstrated both in vitro and in vivo. Especially, the doped rare earth ions in the host endow the material with excellent UCL imaging, magnetic resonance imaging (MRI), and computed tomography (CT) imaging properties, thus realizing the target of multimodal imaging guided multiple therapies.Keywords: bioimaging; GdOF; photodynamic therapy; photothermal therapy; up-conversion;
Co-reporter:Shili Gai, Chunxia Li, Piaoping Yang, and Jun Lin
Chemical Reviews 2014 Volume 114(Issue 4) pp:2343
Publication Date(Web):December 18, 2013
DOI:10.1021/cr4001594
Co-reporter:Jie Xu, Shili Gai, Ping'an Ma, Yunlu Dai, Guixin Yang, Fei He and Piaoping Yang
Journal of Materials Chemistry A 2014 vol. 2(Issue 13) pp:1791-1801
Publication Date(Web):13 Jan 2014
DOI:10.1039/C3TB21465F
In this study, uniform gadolinium fluoride microspheres with controllable phases and structures have been synthesized for the first time by a facile ion exchange process using Gd(OH)CO3 solid microspheres as precursors. It is found that the as-synthesized NaxGdyFx+3y samples, including orthorhombic GdF3, cubic Na5Gd9F32 and hexagonal NaGdF4, all consist of well dispersed microspheres with mesopores. After the conversion process, the products mainly inherit the size and shape of the precursors. Moreover, the used ethylene glycol (EG) plays a key role in the phase and structure of the final NaxGdyFx+3y mesoporous spheres by impacting the etching and ion exchange process. Based on the time-dependent experiments of gadolinium fluorides, the possible formation mechanism is discussed in detail. Under 273 nm UV excitation, NaxGdyFx+3y:2% Eu3+ shows bright red emissions due to efficient energy transfer from Gd3+ to Eu3+. NaxGdyFx+3y:17% Yb3+/3% Er3+ exhibits the characteristic up-conversion (UC) emissions of Er3+. It is noted that the highest DC and UC emission intensities of NaGdF4:Ln should be due to the hexagonal phase. The fluorescent NaxGdyFx+3y mesoporous microspheres show obvious drug (doxorubicin hydrochloride, DOX) storage/release properties and good biocompatibility, suggesting their potential application in biomedical fields.
Co-reporter:Ruichan Lv, Guixin Yang, Fei He, Yunlu Dai, Shili Gai and Piaoping Yang
Nanoscale 2014 vol. 6(Issue 24) pp:14799-14809
Publication Date(Web):13 Oct 2014
DOI:10.1039/C4NR04336G
In this report, uniform LaF3:Ln mesoporous spheres have been synthesized by a facile and mild in situ ion-exchange method using yolk-like La(OH)3:Ln mesoporous spheres as templates, which were prepared through a self-produced bubble-template route. It was found that the structures of the final LaF3:Ln can simply be tuned by adding a polyetherimide (PEI) reagent. LaF3:Ln hollow mesoporous spheres (HMSs) and LaF3:Ln flower-like mesoporous spheres (FMSs) were obtained when assisted by PEI and in the absence of PEI. The up-conversion (UC) luminescence results reveal that the doping of Nd3+ ions in LaF3:Ln can markedly influence the UC emissions of the products. It is interesting that an obvious thermal effect is achieved due to the energy back-transfer from Tm3+ to Nd3+ ions under 980 nm near-infrared (NIR) irradiation. The LaF3:Yb/Er/Tm/Nd HMSs show good biocompatibility and sustained doxorubicin (DOX) release properties. In particular, upon 980 nm NIR irradiation, the photothermal effect arising from the Nd3+ doping induces a faster DOX release from the drug release system. Moreover, UC luminescence images of LaF3:Yb/Er/Tm/Nd HMSs uptaken by MCF-7 cells exhibit apparent green emission under 980 nm NIR irradiation. Such a multifunctional carrier combining UC luminescence and hyperthermia with the chemotherapeutic drugs should be of high potential for the simultaneous anti-cancer therapy and cell imaging.
Co-reporter:Shenghuan Zhang, Shili Gai, Fei He, Shujiang Ding, Lei Li and Piaoping Yang
Nanoscale 2014 vol. 6(Issue 19) pp:11181-11188
Publication Date(Web):24 Jul 2014
DOI:10.1039/C4NR02096K
The easy aggregation nature of ferromagnetic nanoparticles (NPs) prepared by conventional routes usually leads to a large particle size and low loading, which greatly limits their applications to the reduction of 4-nitrophenol (4-NP). Herein, we developed a novel in situ thermal decomposition and reduction strategy to prepare Ni nanoparticles/silica nanotubes (Ni/SNTs), which can markedly prevent the aggregation and growth of Ni NPs, resulting in an ultra-small particle size (about 6 nm), good dispersion and especially high loading of Ni NPs. It was found that Ni/SNTs, which have a high specific surface area (416 m2 g−1), exhibit ultra-high catalytic activity in the 4-NP reduction (complete reduction of 4-NP within only 60 s at room temperature), which is superior to most noble metal (Au, Pt, and Pd) supported catalysts. Ni/SNTs still showed high activity even after re-use for several cycles, suggesting good stability. In particular, the magnetic property of Ni/SNTs makes it easy to recycle for reuse.
Co-reporter:Jie Xu, Fei He, Shili Gai, Shenghuan Zhang, Lei Li and Piaoping Yang
Nanoscale 2014 vol. 6(Issue 18) pp:10887-10895
Publication Date(Web):24 Jul 2014
DOI:10.1039/C4NR02756F
A unique, double-shelled, hollow, carbon-based composite with enriched nitrogen has been prepared through a facile and versatile synthetic strategy. The hierarchical composite employs the nitrogen-enriched carbon hollow sphere as an interior shell and intercrossed Ni/Al layered double hydroxide (LDH) nanosheets as an exterior shell. The obtained N–C@LDH hollow microspheres (HMS) have high nitrogen enrichment, large specific surface area (337 m2 g−1), and uniform and open mesoporous structure. Taking advantage of these characteristics, the composite exhibits obviously superior capacitive behavior, including high specific capacitance, excellent rate capability and good cycling stability, compared with nitrogen-free carbon@LDH composite and hollow LDH without carbon shell. The composite displays high specific capacitance of 1711.51 F g−1 at a current density of 1 A g−1. In particular, the high specific capacitance can be kept to 997.3 F g−1 at a high current density of 10 A g−1, which still retains 94.97% of the initial specific capacitance after 500 cycles at this high current density. This N-enriched, hollow carbon/LDH composite can be expected to be a promising electrode material for electrochemical capacitors due to its high electrochemical performance.
Co-reporter:Lei Li, Rumin Li, Shili Gai, Fei He and Piaoping Yang
Journal of Materials Chemistry A 2014 vol. 2(Issue 23) pp:8758-8765
Publication Date(Web):10 Apr 2014
DOI:10.1039/C4TA01186D
A novel core–shell structured Fe3O4@C@Ni–Al LDH composite containing a carbon-coated Fe3O4 magnetic core and a layered double hydroxide (LDH) has been successfully prepared by a combination of the hydrothermal method and a facile in situ growth process. The Fe3O4@C@Ni–Al LDH microspheres were characterized by X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM), high-resolution transmission electron microscopy (HRTEM), Fourier transformed infrared (FT-IR), X-ray photoelectron spectra (XPS), and N2 adsorption/desorption methods. Owing to the unique layered feature, the composite displays core–shell structure with flower-like morphology, ultra-high surface area (792 m2 g−1) and specific pore size distribution. Moreover, the as-synthesized Fe3O4@C@Ni–Al LDH microsphere as an electrode material was fabricated into a supercapacitor and characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge measurements. It turned out that the Fe3O4@C@Ni–Al LDH exhibits specific capacitance of 767.6 F g−1, good rate capability, and remarkable cycling stability (92% after 1000 cycling). Therefore, such a novel synthetic route to assemble the high-performance electrochemical capacitor may open a new strategy to prepare other materials with largely enhanced electrochemical properties, which can be of great promise in energy storage device applications.
Co-reporter:Wang Yan, Fei He, Shili Gai, Peng Gao, Yujin Chen and Piaoping Yang
Journal of Materials Chemistry A 2014 vol. 2(Issue 10) pp:3605-3612
Publication Date(Web):11 Dec 2013
DOI:10.1039/C3TA14718E
In this study, TiO2 hollow microspheres with high photocatalytic activity were prepared by simply optimizing the ratio of the as-used templates (poly(4-styrenesulfonate) (PSS) and triblock copolymer P123). In particular, a novel three-dimensional (3D) reduced graphene oxide/TiO2 (rGO/TiO2) hybrid composite was for the first time prepared by wrapping TiO2 hollow microspheres with rGO sheets via a facile solvothermal route using poly(L-lysine) (PLL) and ethylene glycol (EG) as coupling agents. The structural, morphological and photocatalytic properties of the as-synthesized products were examined. It is found that rGO/TiO2 hybrid composite exhibits markedly enhanced photocatalytic performance in comparison with pure TiO2 hollow microspheres and the simple mixture of rGO and TiO2 spheres. The rational design, interesting structure and ideal photocatalytic performance of this graphene-based composite show great promise in diverse fields.
Co-reporter:Rumin Li, Lei Li, Yunhua Han, Shili Gai, Fei He and Piaoping Yang
Journal of Materials Chemistry A 2014 vol. 2(Issue 15) pp:2127-2135
Publication Date(Web):24 Jan 2014
DOI:10.1039/C3TB21718C
Gd2O3:Ln@mSiO2 hollow nanospheres (Gd2O3:Ln hollow spheres coated by a mesoporous silica layer) were successfully synthesized through a self-template method using Gd(OH)CO3 as template to form hollow precursors (named HPs), which involved the incorporation of the rare earth compound into the interior of the hydrophilic carbon shell, followed by coating with a mesoporous silica shell, and subsequent calcination in air. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric and differential thermal analyses (TG-DTA), photoluminescence spectroscopy, kinetic decays as well as N2 adsorption/desorption were employed to characterize the composites. The results indicate that the uniform Gd2O3:Ln@mSiO2 composite with the particle size around 300 nm maintains the spherical morphology and good dispersibility of the precursor. Interestingly, the composite has a double-shell structure including an inner shell of Gd2O3 and an outer shell of mesoporous silica. Moreover, they also exhibit bright red (Eu3+, 5D0 → 7F2) down-conversion (DC) emission and characteristic up-conversion (UC) emissions of Yb3+/Er3+. Under beam excitation, the hollow structured sample emits, which should have potential applications in biomedicine and other fields.
Co-reporter:Di Bao, Peng Gao, Xiande Shen, Cheng Chang, Longqiang Wang, Ying Wang, Yujin Chen, Xiaoming Zhou, Shuchao Sun, Guobao Li, and Piaoping Yang
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 4) pp:2902
Publication Date(Web):February 5, 2014
DOI:10.1021/am405458u
The design and synthesis of new hydrogen storage nanomaterials with high capacity at low cost is extremely desirable but remains challenging for today’s development of hydrogen economy. Because of the special honeycomb structures and excellent physical and chemical characters, fullerenes have been extensively considered as ideal materials for hydrogen storage materials. To take the most advantage of its distinctive symmetrical carbon cage structure, we have uniformly coated C60′s surface with metal cobalt in nanoscale to form a core/shell structure through a simple ball-milling process in this work. The X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectra, high-solution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrometry (EDX) elemental mappings, and X-ray photoelectron spectroscopy (XPS) measurements have been conducted to evaluate the size and the composition of the composites. In addition, the blue shift of C60 pentagonal pinch mode demonstrates the formation of Co–C chemical bond, and which enhances the stability of the as-obtained nanocomposites. And their electrochemical experimental results demonstrate that the as-obtained C60/Co composites have excellent electrochemical hydrogen storage cycle reversibility and considerably high hydrogen storage capacities of 907 mAh/g (3.32 wt % hydrogen) under room temperature and ambient pressure, which is very close to the theoretical hydrogen storage capacities of individual metal Co (3.33 wt % hydrogen). Furthermore, their hydrogen storage processes and the mechanism have also been investigated, in which the quasi-reversible C60/Co↔C60/Co–Hx reaction is the dominant cycle process.Keywords: ball-milling; C60/Co; core/shell; Co−C bond; electrochemical hydrogen storage; nanocomposite;
Co-reporter:Ruichan Lv, Piaoping Yang, Yunlu Dai, Shili Gai, Fei He, and Jun Lin
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 17) pp:15550
Publication Date(Web):August 20, 2014
DOI:10.1021/am504347e
Uniform Na5Lu9F32 hollow mesoporous spheres (HMSs) have been successfully prepared by a facile and mild (50 °C for 5 h) coprecipitation process, and Au nanocrystals (NCs) with particle size of about 10 nm were conjugated to poly(ether imide) (PEI) modified HMSs by electrostatic interaction. Compared with Na5Lu9F32:Yb/Er HMSs, the up-conversion (UC) luminescence intensity of Na5Lu9F32:Yb/Er@Au HMSs was much higher under low pump power due to the local field enhancement (LFE) of Au NCs, and there is a surface plasmon resonance (SPR) effect with nonradiative transitions which generates a thermal effect. These two effects have been proved by theoretical discrete-dipole approximation (DDA) simulation. The good biocompatibility of Na5Lu9F32:Yb/Er@Au HMSs indicates them as a promising candidate in the biological field. Particularly, under near-infrared (NIR) laser irradiation, a rapid doxorubicin (DOX) release was achieved due to the thermal effect of Au NCs. In this case, Na5Lu9F32:Yb/Er@Au HMSs exhibit an apparent NIR light-controlled “on/off” drug release pattern. In addition, UC luminescent images uptaken by cells show brighter green and red emission under NIR laser excitation. Therefore, this novel multifunctional (mesoporous, enhanced UC luminescent, and light-triggered drug release) material should be potential as a suitable targeted cancer therapy carrier and bioimaging.Keywords: hollow; light-triggered; mesoporous; up-conversion luminescence
Co-reporter:Na Niu, Fei He, Ping’an Ma, Shili Gai, Guixin Yang, Fengyu Qu, Yan Wang, Jie Xu, and Piaoping Yang
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 5) pp:3250
Publication Date(Web):February 12, 2014
DOI:10.1021/am500325w
A facile process for the preparation of multifunctional nanospheres combining several advantages of mesoporous channels, up-conversion (UC) luminescence, and photothermal responses into one single entity is reported. First, Gd2O3:Yb/Er assembled mesoporous silica with 2D hexagonal (MCM-41) and 3D cubic (MCM-48) network have been prepared via a one-step procedure. Then, gold nanocrystals with diameter of 5 nm are integrated with the amino group functionalized nanocomposites. Upon 980 nm near infrared (NIR) laser irradiation, a wavelength-dependent enhancement of the UC intensities is observed due to the surface plasmon resonance (SPR) effect of attached gold nanoparticles. These composites have good biocompatibility and sustained anticancer drug (doxorubicin, DOX) release properties, making it a promising candidate for drug delivery. Particularly, under 980 nm NIR laser irradiation, the green UC emission overlaps the SPR band of gold nanocrystals, which causes a photothermal effect of gold nanocrystals and induces a rapid DOX release from the Au hybrid materials. This DOX loaded multifunctional system has an obvious cytotoxic effect and photothermally killing enhanced effect on SKOV3 ovarian cancer cells. The endocytosis process was also demonstrated through confocal laser scanning microscope (CLSM) images. Such novel multifunctional anticancer drug delivery systems, which combine hyperthermia with the chemotherapeutic drugs by synergistic effect, should be of high potential in cancer therapy.Keywords: drug release; mesoporous silica; plasmon-enhancement; up-conversion;
Co-reporter:Cheng Chang, Peng Gao, Di Bao, Longqiang Wang, Ying Wang, Yujin Chen, Xiaoming Zhou, Shuchao Sun, Guobao Li, Piaoping Yang
Journal of Power Sources 2014 Volume 255() pp:318-324
Publication Date(Web):1 June 2014
DOI:10.1016/j.jpowsour.2014.01.034
•1D CNT (CNF)/Co nanocomposites were synthesized by a ball-milling method.•Co shell with diameter of 4 nm has been successfully coated on CNT.•The composites exhibited good hydrogen storage performance.Owing to the special honeycomb structures and excellent electrical characters of carbon nanotube (CNT) and carbon nanofiber (CNF), they are extensively considered as ideal cornerstones for hydrogen storage materials. Herein, metal cobalt has been uniformly coated on CNT's and CNF's surfaces in nanoscale through a simple ball milling process. Accordingly their X-ray diffraction, scanning electron microscope and transmission electron microscopy measurements clarify the satisfying composite structures. And their electrochemical experimental results demonstrate that the as-obtained CNT/Co and CNF/Co composites have excellent electrochemical hydrogen storage reversibility and considerably high storage capacities of 717.3 mAh g−1 (2.62 wt% hydrogen) and 739.4 mAh g−1 (2.70 wt% hydrogen) under room temperature and ambient pressure, which are much higher than the capacities of individual CNT (29.9 mAh g−1, 0.11 wt% hydrogen) and CNF (49.0 mAh g−1, 0.18 wt% hydrogen) measured in this work. Furthermore their hydrogen storage processes and the mechanism have also been investigated, in which the quasi-reversible CNT (CNF)/Co ↔ CNT (CNF)/Co–Hx reaction is the dominant cycle process.
Co-reporter:Jie Xu, Lei Li, Fei He, Ruichan Lv, Piaoping Yang
Electrochimica Acta 2014 Volume 148() pp:211-219
Publication Date(Web):1 December 2014
DOI:10.1016/j.electacta.2014.10.061
Herein, double-shelled hollow architecture composed of carbon inner shell and flower-like NiO exterior shell has been prepared through a facile hydrothermal process, followed by a heat treatment. Taking SiO2@RF (resorcinol–formaldehyde resin, RF) sphere as template, the flower-like NiSilicate shell was grown on the surface of RF during the formation of hollow inner structure. The calcination process in the inert atmosphere gives rise to the carbonization and decomposition simultaneously, leading to the formation of carbon-based NiO hollow spheres (C@NiO HSs) with similar structure to that of the parent precursor, which possess large specific surface area (217 m2 g−1) and favorable pore structure for supercapacitor application. It is found that C@NiO composite shows higher electrochemical performance than that of pure NiO hollow sphere without interior carbon shell. The C@NiO hollow spheres have high specific capacitance of 211 F/g at the current density of 1 A/g and good cycle stability (84.6%) after 1000 cycles at the current density of 5 A/g, which are superior to NiO HSs without carbon shell. The synthetic strategy can be expanded to fabricate other functional hybrid materials, which should be potential in diverse fields.C@NiO hollow spheres with double-shelled structure were prepared through a hydrothermal process followed by a heat treatment, using resorcinol–formaldehyde resin (RF) coated SiO2 sphere as template, which show high supercapacitor performance.
Co-reporter:Ying Wang, Peng Gao, Di Bao, Longqiang Wang, Yujin Chen, Xiaoming Zhou, Piaoping Yang, Shuchao Sun, and Milin Zhang
Inorganic Chemistry 2014 Volume 53(Issue 23) pp:12289-12296
Publication Date(Web):November 13, 2014
DOI:10.1021/ic5014126
Many modern technologies rely on the functional materials that are subject to their phase purity. The topic of obtaining pure crystals from the concomitant allotropes is ever before the eyes of numerous researchers. Here we adopt a template-inducing route and obtain the isolated allotropes located in the appointed regions in the same reaction system. As a typical example, well-defined individual face-centered cubic and orthorhombic ZnSnO3 crystals were successfully synthesized assisted by a ZnO inducing template or without it in an identical solution, respectively. And the different growing mechanisms of the ZnSnO3 allotropes were also proposed, which takes a pivotal step toward the realization of allotropes dividing. Moreover, the two individual pure-phased ZnSnO3 allotropes obtained in one reaction system exhibit porous microspherical morphologies constructed by the tiny nanograins, resulting in their high sensitivities to ethanol with fast response and recovery and good selectivity and stability.
Co-reporter:Guixin Yang, Ruichan Lv, Shili Gai, Yunlu Dai, Fei He, and Piaoping Yang
Inorganic Chemistry 2014 Volume 53(Issue 20) pp:10917-10927
Publication Date(Web):October 6, 2014
DOI:10.1021/ic501121t
A series of hollow and luminescent capsules have been fabricated by covering luminescent Gd2O3:Yb/Tm nanoparticles on the surface of uniform hollow mesoporous silica capsules (HMSCs), which were obtained from an etching process using Fe3O4 as hard templates. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), up-conversion (UC) fluorescence spectra, and N2 adsorption–desorption were used to characterize these samples. It is found that the as-prepared products have mesoporous pores, large specific surface, and high dispersity. In particular, the size, shape, surface area, and interior space of the composites can be finely tuned by adjusting the size and morphology of the magnetic cores. Under 980 nm near-infrared (NIR) laser irradiation, the composites show characteristic blue UC emissions of Tm3+ even after carrying doxorubicin hydrochloride (DOX). The drug-release test reveals that the capsules showed an apparent sustained release character and released in a pH-sensitive manner. Interestingly, the UC luminescence intensity of the drug-carrying system increases with the released DOX, realizing the possibility to track or monitor the released drug by the change of UC fluorescence simultaneously, which should be highly promising in anticancer drug delivery and targeted cancer therapy.
Co-reporter:Ruichan Lv, Shili Gai, Yunlu Dai, Fei He, Na Niu, and Piaoping Yang
Inorganic Chemistry 2014 Volume 53(Issue 2) pp:998-1008
Publication Date(Web):December 23, 2013
DOI:10.1021/ic402468k
Uniform LaF3 and LaCO3F hollow microspheres were successfully synthesized through a surfactant-free route by employing La(OH)CO3 colloidal microspheres as a sacrificial template and NaBF4 as the fluorine source. The synthetic process consists of two steps: the preparation of a La(OH)CO3 precursor via a facile urea-based precipitation and the following formation of lanthanide fluoride hollow microspheres under aqueous conditions at low temperature (50 °C) and short reaction time (3 h), without using any surfactant and catalyst. The formation of hollow spheres with controlled size can be assigned to the Kirkendall effect. It is found that the phase and structure of the products can be simply tuned by changing the pH values of the solution. Time-dependent experiments were employed to study the possible formation process. N2 adsorption/desorption results indicate the mesoporous nature of LaF3 hollow spheres. Yb3+/Er3+ (Ho3+) and Yb3+/Tm3+-doped LaF3 hollow spheres exhibit characteristic up-conversion (UC) emissions of Er3+ (Ho3+) and Tm3+ under 980 nm laser-diode excitation, and Ce3+/Tb3+-doped LaF3 and LaCO3F emit bright yellow-green and near-white light under UV irradiation, respectively. In particular, LaF3:Yb/Er and LaCO3F:Ce/Tb hollow microspheres exhibit obvious sustained and pH-dependent doxorubicin release properties. The luminescent properties of the carriers allow them to be tracked or monitored during the release or therapy process, suggesting their high potential in the biomedical field.
Co-reporter:Jie Xu, Shili Gai, Fei He, Na Niu, Peng Gao, Yujin Chen and Piaoping Yang
Dalton Transactions 2014 vol. 43(Issue 30) pp:11667-11675
Publication Date(Web):07 May 2014
DOI:10.1039/C4DT00686K
Reduced graphene oxide (rGO) sheet and ternary-component Ni1−xCoxAl-layered double hydroxide (Ni1−xCoxAl-LDH) hybrid composites with an interesting sandwich structure have been fabricated by an in situ growth route. The as-obtained composite displays a sandwich architecture constructed by the self-assembly of sheet-like LDH crystals on both sides of the rGO sheets. It was found that the Co content doped in Ni1−xCoxAl-LDH plays an important role in the shape and structure of the final products. When the Co doped content is 17%, the rGO/Ni0.83Co0.17Al-LDH has a high surface area (171.5 m2 g−1) and exhibits a perfect sandwich structure. In addition, this structure and morphology is favorable for a supercapacitor electrode material with a high performance. The influence of cobalt content on the electrochemical behavior of rGO/Ni1−xCoxAl-LDH has been systematically studied. The results indicate that the rGO/Ni0.83Co0.17Al-LDH composite exhibits the highest electrochemical performance, with a specific capacitance of 1902 F g−1 at 1 A g−1, and an excellent cycling stability. The markedly improved electrochemical performance is superior to undoped rGO/NiAl-LDH and can be attributed to the enhanced conductivity achieved through cobalt doping. Such composites could be used as a type of potential energy storage/conversion material for supercapacitors.
Co-reporter:Lei Li, Fei He, Shili Gai, Shenghuan Zhang, Peng Gao, Milin Zhang, Yujin Chen and Piaoping Yang
CrystEngComm 2014 vol. 16(Issue 42) pp:9873-9881
Publication Date(Web):01 Sep 2014
DOI:10.1039/C4CE01323A
Binary metal oxide MnCo2O4 nanosheets wrapped on a hollow activated carbon shell (C@MnCo2O4) were successfully synthesized through a facile hydrothermal method followed by a calcination process. The novel structure of a flower-like C@MnCo2O4 composite, which consists in a good conductive carbon shell and well interconnected nanosheets, can efficiently facilitate electrolyte penetration and offers an expedite transport path for ions and electrons. Notably, the large surface of the hybrid composite (347 m2 g−1) can provide a large amount of active sites, which evidently accommodates the strain during cycling. Benefiting from this elegant combination and the effectively mesoporous structure, the specific capacitance of the C@MnCo2O4 composite can be achieved as high as 728.4 F g−1, which is, to the best of our knowledge, the highest value so far reported for MnCo2O4 based electrode materials. In addition, the C@MnCo2O4 composite exhibits enhanced rate capability and an excellent cycling stability of 95.9% retention after 1000 cycles at a high current density of 8 A g−1. Therefore, the desirable integrated electrical performance allows it to be a promising electrode material for supercapacitor applications.
Co-reporter:Ruichan Lv, Guixin Yang, Yunlu Dai, Shili Gai, Fei He and Piaoping Yang
CrystEngComm 2014 vol. 16(Issue 41) pp:9612-9621
Publication Date(Web):07 Jul 2014
DOI:10.1039/C4CE01063A
We report for the first time a self-produced bubble-template synthesis of La2O3:Yb/Er hollow mesoporous spheres (HMSs) through a facile one-step co-precipitation process. The temperature, which determines bubble formation, and the amounts of citric acid and NaOH, which determine dispersibility, are the main factors in the formation of La2O3:Yb/Er HMSs. Au nanocrystals (NCs) with a particle size of 9 nm were conjugated to the as-prepared HMSs without adding any organic reagents. It is noted that the up-conversion (UC) luminescence intensity of La2O3:Yb/Er@Au was markedly improved by 49.7-fold under low pump power, and the lifetime has been greatly enhanced due to the local field enhancement (LFE) of Au NCs, which effectively prevents the energy transfer from La2O3:Yb/Er to Au nanoparticles (NPs). The enhanced properties have been successfully proved by discrete-dipole approximation (DDA) simulation. The as-prepared La2O3:Yb/Er@Au HMSs with large surface area (118 m2 g−1) and mesoporous feature (2.92 nm in pore size) exhibit good compatibility. In addition, doxorubicin (DOX) release properties and obvious cytotoxicity to MCF-7 tumor cells reveal their potential application as a drug carrier. In particular, the facile and mass-production synthetic strategy may pave the way for the production of a wide class of materials.
Co-reporter:Longqiang Wang, Peng Gao, Di Bao, Ying Wang, Yujin Chen, Cheng Chang, Guobao Li, and Piaoping Yang
Crystal Growth & Design 2014 Volume 14(Issue 2) pp:569-575
Publication Date(Web):January 3, 2014
DOI:10.1021/cg401384t
Considering the specific surface area, flexible structures, high porosity, and a homogeneous and isotropic nature down to the atomic scale possessed by the amorphous nanostructure, an interesting controlled dehydration route has been developed to synthesize the crystalline/amorphous core/shell (C/A-C/S) MoO3 nanocomposite, in which macroisopolyanion [Mo36O112(H2O)16]8– ({Mo36}) was successfully assembled into a one-dimensional connection and underwent a deficient crystallization induced by the prospective infiltrative dehydration process. The as-obtained MoO3 samples’ affirmative composition and composite structure have been further demonstrated by the XRD, TEM, HRTEM, and Raman spectra measurements. As a result of this special C/A-C/S structure, the MoO3 composite exhibited high selectivity and a higher sensor response, at a lower working temperature (180 °C) to ethanol gas compared with other 1D MoO3 micro/nanostructures reported previously.
Co-reporter:Zhongyi Niu, Shenghuan Zhang, Yanbo Sun, Shili Gai, Fei He, Yunlu Dai, Lei Li and Piaoping Yang
Dalton Transactions 2014 vol. 43(Issue 44) pp:16911-16918
Publication Date(Web):15 Sep 2014
DOI:10.1039/C4DT02385D
The high cost of noble metal nanoparticles used for catalytic reduction of 4-nitrophenol (4-NP) leads to an extensive study of Ni nanoparticles (NPs) for their low cost and magnetic properties. However, the conventional routes for preparing the ferromagnetic Ni NPs usually lead to large particle size and aggregation. In this study, we propose a simple two-step method for the synthesis of hierarchical Ni NP supported silica magnetic hollow microspheres (Ni/SiO2 MHMs). Tiny Ni NPs are well dispersed on the supports with high loading amounts (15 wt%). The size of Ni NPs can be tuned from 10 nm to 21 nm with the size of Ni/SiO2 MHMs increasing from 230 nm to 800 nm. The as-prepared samples exhibit excellent catalytic activity in the reduction of 4-NP. Furthermore, the experimental results prove that the size of Ni NPs plays an important role in the catalytic activity. The catalytic activity of small sized Ni NPs is higher than that of large sized and many other supported Ni NP catalysts as reported. In particular, the magnetic properties of Ni/SiO2 MHMs make them easy to recycle for reuse.
Co-reporter:Ruichan Lv, Guixin Yang, Shili Gai, Yunlu Dai, Fei He and Piaoping Yang
RSC Advances 2014 vol. 4(Issue 108) pp:63425-63435
Publication Date(Web):18 Nov 2014
DOI:10.1039/C4RA12942C
Uniform LaPO4:Ce/Tb mesoporous microspheres (MMs) have been successfully prepared by a facile mass production co-precipitation process under mild reaction conditions, without using any surfactant, catalyst or further heating treatment. Then, Au nanoparticles (NPs) were conjugated to polyetherimide (PEI) modified LaPO4:Ce/Tb MMs by electrostatic interactions. It was found that as-prepared LaPO4:Ce/Tb@Au composite consists of well-dispersed mesoporous microspheres with high surface area and narrow pore size distribution. Upon ultraviolet (UV) excitation, LaPO4:Ce/Tb and LaPO4:Ce/Tb@Au MMs exhibit the characteristic green emissions of Tb3+ ions. In addition, the good biocompatibility and sustained doxorubicin (DOX) release properties indicate its promise as a candidate in cancer therapy. In particular, under UV irradiation, a rapid DOX release was achieved due to the photothermal effect of Au NPs derived from the overlap of the green emission of Tb3+ and the surface plasmon resonance (SPR) band of gold NPs at about 530 nm. The MTT assay, cellular uptaken images, the anti-tumor therapy in vivo, and the histology examination results further proved that this novel multifunctional (mesoporous, luminescent, and thermal effect) drug delivery system should be a suitable candidate for cancer therapy carriers.
Co-reporter:Yunlu Dai ; Haihua Xiao ; Jianhua Liu ; Qinghai Yuan ; Ping’an Ma ; Dongmei Yang ; Chunxia Li ; Ziyong Cheng ; Zhiyao Hou ; Piaoping Yang ;Jun Lin
Journal of the American Chemical Society 2013 Volume 135(Issue 50) pp:18920-18929
Publication Date(Web):November 26, 2013
DOI:10.1021/ja410028q
Controlling anticancer drug activity and release on demand is very significant in cancer therapy. The photoactivated platinum(IV) pro-drug is stable in the dark and can be activated by UV light. In this study, we develop a multifunctional drug delivery system combining upconversion luminescence/magnetic resonance/computer tomography trimodality imaging and NIR-activated platinum pro-drug delivery. We use the core–shell structured upconversion nanoparticles to convert the absorbed NIR light into UV to activate the trans-platinum(IV) pro-drug, trans,trans,trans-[Pt(N3)2(NH3)(py)(O2CCH2CH2COOH)2]. Compared with using the UV directly, the NIR has a higher tissue penetration depth and is less harmful to health. Meanwhile, the upconversion nanoparticles can effectively deliver the platinum(IV) pro-drugs into the cells by endocytosis. The mice treated with pro-drug-conjugated nanoparticles under near-infrared (NIR) irradiation demonstrated better inhibition of tumor growth than that under direct UV irradiation. This multifunctional nanocomposite could be used as multimodality bioimaging contrast agents and transducers by converting NIR light into UV for control of drug activity in practical cancer therapy.
Co-reporter:Fei He, Na Niu, Fengyu Qu, Shuquan Wei, Yujin Chen, Shili Gai, Peng Gao, Yan Wang and Piaoping Yang
Nanoscale 2013 vol. 5(Issue 18) pp:8507-8516
Publication Date(Web):28 Jun 2013
DOI:10.1039/C3NR03038E
The reduced graphene oxide (rGO) supported cobalt nanocrystals have been synthesized through an in situ crystal growth method using Co(acac)2 under solvothermal conditions by using DMF as the solvent. By carefully controlling the reaction temperature, the phase transition of the cobalt nanocrystals from the cubic phase to the hexagonal phase has been achieved. Moreover, the microscopic structure and morphology as well as the reduction process of the composite have been investigated in detail. It is found that oxygen-containing functional groups on the graphene oxide (GO) can greatly influence the formation process of the Co nanocrystals by binding the Co2+ cations dissociated from the Co(acac)2 in the initial reaction solution at 220 °C, leading to the 3D reticular structure of the composite. Furthermore, this is the first attempt to use a Co/rGO composite as the catalyst in the F–T CO2 hydrogenation process. The catalysis testing results reveal that the as-synthesized 3D structured composite exhibits ideal catalytic activity and good stability, which may greatly extend the scope of applications for this kind of graphene-based metal hybrid material.
Co-reporter:Yan Wang, Piaoping Yang, Ping'an Ma, Fengyu Qu, Shili Gai, Na Niu, Fei He and Jun Lin
Journal of Materials Chemistry A 2013 vol. 1(Issue 15) pp:2056-2065
Publication Date(Web):31 Jan 2013
DOI:10.1039/C3TB00377A
In this study, a facile and mild one-pot approach was employed to prepare hollow-structured SrMoO4 spheres using soluble sodium poly(4-styrenesulfonate) (PSS) as a soft template. It is found that the as-prepared product exhibits hollow spherical morphology, good dispersity, and narrow size distribution. The formation mechanism has also been proposed. Tunable multicolor and bright white up-conversion (UC) emissions were successfully realized by precisely adjusting the doping sensitizer (Yb3+) and activator (Tm3+, Ho3+, and Tm3+/Ho3+) concentration in the host matrix. MTT assay shows the good biocompatibility of SrMoO4:Yb3+/Tm3+ hollow spheres, which were used as an anti-cancer drug carrier to evaluate the loading and controlled release behavior by selecting doxorubicin hydrochloride (DOX) as a model drug. Drug release tests reveal a sustained drug release behavior and especially the UC emission intensities of the drug loaded system increase with the released amount of DOX, indicating that the extent of drug release can be monitored or tracked by the change in emission intensity. Moreover, the in vitro cytotoxic effect against SKOV3 ovarian cancer cells of the DOX-loaded carrier was investigated and the endocytosis process of drug-loaded microspheres was studied using confocal laser scanning microscopy (CLSM) and flow cytometry. Considering the good biocompatibility, high drug loading amount and obvious sustained drug release properties, the hollow microspheres are highly promising in biological areas.
Co-reporter:Yan Wang, Shili Gai, Na Niu, Fei He and Piaoping Yang
Journal of Materials Chemistry A 2013 vol. 1(Issue 32) pp:9083-9091
Publication Date(Web):21 May 2013
DOI:10.1039/C3TA11161J
A novel structured reduced graphene oxide/Ni(OH)2 (rGO/Ni(OH)2) hybrid composite with enhanced electrochemical performance was prepared by wrapping β-Ni(OH)2 hollow microspheres in rGO sheets via a facile solvothermal route, using poly(L-lysine) (PLL) as reductant and ethylene glycol (EG) as coupling agent. The structural, morphological and electrochemical properties of the composite were well examined. The results show that single-crystalline β-Ni(OH)2 hollow microspheres are enveloped in rGO sheets after thermal treatment in the hybrid composite, which exhibits a high specific capacitance of 1551.8 F g−1 at a current density of 2.67 A g−1 and a capacity retention of 102% after 2000 cycles. Notably, in comparison with pure β-Ni(OH)2 hollow microspheres and the simple mixture (mixture of rGO and Ni(OH)2 spheres), the rGO/β-Ni(OH)2 composite exhibited superior electrochemical properties, which may be due to the wrapped electrically conducting graphene sheets and the unique three-dimensional (3D) structure of the composite. The rational design, interesting structure and the ideal electrochemical performance of this graphene-based composite suggest its potential applications in high energy storage systems.
Co-reporter:Guixin Yang, Shili Gai, Fengyu Qu, and Piaoping Yang
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 12) pp:5788
Publication Date(Web):May 24, 2013
DOI:10.1021/am401349z
A novel bifunctional (fluorescent, mesoporous) hollow sphere was prepared by coating luminescent YBO3:Eu3+ nanoparticles onto uniform hollow mesoporous silica spheres (HMSs), derived from an etching strategy using spherical Fe3O4 as templates. The composites exhibit typical mesoporous shells, large interior space, high surface area, and well dispersed nanospheres with controlled size. In addition, the textural properties including the specific surface and pore volume can be easily altered by simply tuning of the spherical Fe3O4 cores. Upon ultraviolet (UV) excitation, the composite shows the characteristic 5D0–7F1–4 red emission lines of Eu3+ even after loading of the model drug. The composite with a large surface area and cavity was used as the host for loading the anticancer drug doxorubicin hydrochloride (DOX). It is observed that the multifunctional composites exhibit an obvious sustained release property and released in texture- and pH-sensitive patterns. Particularly, the down-conversion (DC) fluorescence intensity of the bifunctional vehicle increases with the release of drug molecules, making it possible to track the position and the drug release amount of the drug carrier system and to detect them by the change of fluorescence intensity.Keywords: drug release; hollow; luminescence; mesoporous; silica; YBO3:Eu3+;
Co-reporter:Ruichan Lv, Shili Gai, Yunlu Dai, Na Niu, Fei He, and Piaoping Yang
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 21) pp:10806
Publication Date(Web):October 9, 2013
DOI:10.1021/am4041652
In this paper, uniform hollow mesoporous GdF3 micro/nanospheres were successfully prepared by a facile two-step synthesis route without using any surfactant, catalyst, and further calcination process. The precursor Gd(OH)CO3 spheres are prepared by a coprecipitation process. After that, uniform and size-tunable GdF3 hollow spheres were easily coprecipitated with NaBF4 at the sacrifice of the precursor with low temperature and short reaction time. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution TEM, N2 adsorption/desorption, and up-conversion (UC) photoluminescence spectra were used to characterize the as-obtained products. It is found that the initial pH value and NaBF4/Gd3+ molar ratios play important roles in the structures, sizes, and phases of the hollow products. The growth mechanism of the hollow spheres has been systematically investigated based on the Kirkendall effect. Under 980 nm IR laser excitation, UC luminescence of the as-prepared Yb3+/Er3+-codoped GdF3 hollow spheres can be changed by a simple adjustment of the concentration of the Yb3+ ion. Enhanced red emission is obtained by introducing Li+ ions in GdF3:Yb3+/Er3+. Furthermore, a doxorubicin release experiment and a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide cytotoxicity assay reveal that the product has potential application in drug delivery and targeted cancer therapy.Keywords: drug release; GdF3; hollow; luminescence; MTT; spheres;
Co-reporter:Dandan Han, Pengcheng Xu, Xiaoyan Jing, Jun Wang, Piaoping Yang, Qihui Shen, Jingyuan Liu, Dalei Song, Zan Gao, Milin Zhang
Journal of Power Sources 2013 Volume 235() pp:45-53
Publication Date(Web):1 August 2013
DOI:10.1016/j.jpowsour.2013.01.180
Hierarchical NiO nanospheres composed of porous nanosheets are prepared by a facile trisodium citrate assisted precipitation route followed by a calcination process. Effects of the trisodium citrate on the microstructure and electrochemical performances of NiO nanospheres are systematically investigated. The XRD, SEM, TEM, BET, and TG analyses show that the key point of the successful realization is that the citrate positioned in the precursor α-Ni(OH)2 layer, which can prevent the restacking of α-Ni(OH)2 sheets, yielding better crystallinity, high surface area (182 m2 g−1) as well as pore volume (0.15 cm3 g−1) and hierarchical porous ball-like morphology of NiO nanospheres by the calcination of the precursor. Electrochemical results show that the hierarchically porous NiO obtained with trisodium citrate assisted route exhibits high rate charge–discharge performance (463 F g−1 at 4.5 A g−1), longer cyclic stability (95% capacitance remained after 1000 charge–discharge cycles at 0.5 A g−1) as compared to the NiO prepared in the absence of sodium citrate (182 F g−1 at 4.5 A g−1; 70% capacitance retention after 1000 charge–discharge cycles at 0.5 A g−1). Further, due to facile mass transfer in the perfectly porous nanosheet, the citrate-assisted NiO show lower equivalent series resistance as revealed from the impedance studies.Graphical abstractHierarchical NiO microspheres composed of porous nanosheets were prepared by a facile trisodium citrate assisted precipitation route followed by a calcination process. The sodium citrate assisted obtained NiO has high specific surface area, large pore volume, and narrow pore size distribution. Significantly, compared with the ordinary NiO, the unique hierarchical NiO spheres showed a remarkable discharge capacity and electrochemical stability due to the unique morphology and pore size distribution. Highlights► NiO samples were synthesized using a facile trisodium citrate assisted route. ► Citrate positioned in the precursor interlayer to control the morphology and size. ► Citrate-assisted NiO showed higher specific capacitance and lower ESR. ► Citrate-assisted NiO exhibited good cycling stability and capacitance retention.
Co-reporter:Yunhua Han, Shili Gai, Ping’an Ma, Liuzhen Wang, Milin Zhang, Shaohua Huang, and Piaoping Yang
Inorganic Chemistry 2013 Volume 52(Issue 16) pp:9184-9191
Publication Date(Web):July 30, 2013
DOI:10.1021/ic4001818
Highly uniform α-NaYF4:Yb/Er hollow microspheres have been successfully prepared via a simple two-step route. First, the core–shell structured MF@Y(OH)CO3:Yb/Er precursor was fabricated by a urea-based homogeneous precipitation method using colloidal melamine formaldehyde (MF) microspheres as template. Then the Y(OH)CO3:Yb/Er precursor was transformed into hollow NaYF4:Yb/Er (α and β mixed phase) by a subsequent solvothermal method, and MF microspheres were dissolved in the solvent simultaneously. The mixed phase of NaYF4:Yb/Er was transferred into pure α-NaYF4:Yb/Er by calcination. The as-prepared hollow microspheres were well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectrum (EDS), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and upconversion (UC) luminescence spectroscopy. It is found that the template can be removed without additional calcination or etching process. α-NaYF4:Yb/Er hollow microspheres exhibit bright upconversion (UC) luminescence under 980 nm laser diode (LD) excitation. Furthermore, the hollow microspheres show sustained and pH-dependent doxorubicin hydrochloride (DOX) release properties; in particular, the emission intensity increases with the release amount of drug, making the release process able to be tracked or monitored by the change of the emission intensity, which demonstrates the high potential of this kind of hollow fluorescent material in drug delivery fields.
Co-reporter:Yan Wang, Shili Gai, Na Niu, Fei He and Piaoping Yang
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 39) pp:16795-16805
Publication Date(Web):08 Aug 2013
DOI:10.1039/C3CP52813H
In this paper, NaYF4 microcrystals with a variety of morphologies, such as microsphere, hexagonal prism, microtube and octahedron shapes, have been synthesized via a hydrothermal method using sodium poly(4-styrenesulfonate) (PSS) as a template. The structural and kinetic factors that govern the phase and shape evolution of NaYF4 microcrystals have been systematically studied. And the influence of reaction time, pH values, fluoride sources and reaction temperature on the phase and shape of the as-synthesized NaYF4 was systematically investigated and discussed. It is found that PSS can be employed as a shape modifier, which is responsible for the shape evolution. The possible formation mechanism for the products with various architectures has been presented. The up-conversion (UC) properties of Yb3+/Ho3+, Yb3+/Er3+ or Yb3+/Tm3+ codoped NaYF4 samples were studied. In particular, the luminescence intensity can be markedly enhanced by Li+ doping, the related mechanism has been discussed. Furthermore, a systematic study on the UC emissions of Yb3+/Tm3+ codoped NaYF4 samples with microsphere, hexagonal prism, microtube and octahedron shapes has shown that the optical properties of these phosphors are strongly dependent on their morphologies and sizes. This study would be suggestive for the precisely controlled growth of inorganic crystals, especially for those rare earth fluoride compounds.
Co-reporter:Fei He, Na Niu, Lin Wang, Jie Xu, Yan Wang, Guixin Yang, Shili Gai and Piaoping Yang
Dalton Transactions 2013 vol. 42(Issue 27) pp:10019-10028
Publication Date(Web):23 Apr 2013
DOI:10.1039/C3DT00029J
In this article, rare earth (RE) ion doped β-NaGdF4 crystals with multicolor up-conversion (UC) emissions and paramagnetic properties were synthesized via a simple one-step precipitation method at room-temperature for the first time. Different surfactants, including Na2EDTA, PVP, SDS, and Na2tar, were introduced to control the crystal size and morphology. It was found that the organic additive can strongly control the size and structure of as-prepared β-NaGdF4:Yb3+,Ln3+ samples through absorbing on the surface of primary particles and/or coordinating with RE3+ ions. Most interestingly, the UC and magnetic properties of the NaGdF4 crystals were also greatly influenced by those additives, which exhibit great distinction. The red emission of 4F9/2 → 4I15/2 (655 nm) in β-NaGdF4:20%Yb3+,2%Er3+, 5F5 → 5I8 (648 nm) in β-NaGdF4:20%Yb3+,2%Ho3+, and NIR emission of 3H4 → 3H6 (797 nm) in β-NaGdF4:20%Yb3+,2%Tm3+ were all markedly enhanced due to abundant organic groups that affect the nonradiative processes. The magnetic properties of β-NaGdF4:Yb3+,Er3+ crystals prepared with different surfactants exhibit typical paramagnetic behavior with different intensities due to the different crystal shape anisotropy.
Co-reporter:Hongbo Fu, Guixin Yang, Shili Gai, Na Niu, Fei He, Jie Xu and Piaoping Yang
Dalton Transactions 2013 vol. 42(Issue 22) pp:7863-7870
Publication Date(Web):04 Dec 2012
DOI:10.1039/C2DT32557H
In this paper, well-defined and regular-shaped Na3ScF6 nanocrystals (NCs) have been synthesized in high boiling organic solvents 1-octadecene (ODE) and oleic acid (OA), via the thermal decomposition of rare-earth oleate precursors. It is found that highly uniform monoclinic Na3ScF6 NCs with narrow size distribution have been obtained, which can easily be dispersed in cyclohexane solvent to form transparent colloid solutions. Upon 980 laser diode (LD) excitation, the relative up-conversion (UC) emission intensities of different colors in Yb3+/Er3+, Yb3+/Tm3+ and Yb3+/Ho3+ doped Na3ScF6 can be tuned by altering the Yb3+ doping concentration, resulting in the tunable multicolor in a wide range. On the basis of the emission spectra and the plot of luminescence intensity to pump power, the UC mechanisms of the co-doped Na3ScF6 NCs were investigated in detail. Moreover, the UC emission intensities can be significantly improved by coating a layer of Na3ScF6:Yb3+/Ln3+ shell on Na3ScF6:Yb3+/Ln3+ cores with respect to that of pure Na3ScF6:Yb3+/Ln3+ core NCs. Furthermore, transparent and UC luminescent NCs/polydimethylsiloxane (PDMS) composites with regular dimensions were also fabricated by an in situ polymerization route. Uniform NCs with a wide variation of luminescence colors will show potential applications in diverse fields.
Co-reporter:Yan Wang, Shili Gai, Chunxia Li, Xiao Zhang, Na Niu, Fei He, Milin Zhang and Piaoping Yang
RSC Advances 2013 vol. 3(Issue 17) pp:5945-5955
Publication Date(Web):17 Jan 2013
DOI:10.1039/C3RA22615H
SrMoO4 hollow microstructures with tailored morphologies, sizes and dimensions were synthesized with the assistance of sodium poly(4-styrenesulfonate) (PSS) under mild reaction conditions. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectrum (EDS), down-conversion photoluminescence (PL) and cathodoluminescence (CL) spectra were employed to characterize the samples. The results indicate that the phase, morphology and size of the SrMoO4 microstructures can be rationally tuned in a controlled manner by altering the amount of PSS, the concentration of reactants and the pH value of the initial solutions. Moreover, the crystal growth process was thoroughly studied through a series of time-dependent experiments and a possible formation mechanism was proposed on the basis of Ostwald ripening. Upon ultraviolet (UV) excitation and low voltage electron beams, SrMoO4:Ln3+ (Ln = Eu, Tb) hollow microstructures exhibit bright red (Eu3+, 5D0 → 7F2) and green (Tb3+, 5D4 → 7F5) luminescence. A doxorubicin hydrochloride (DOX) release test exhibited clear sustained drug release property. Notably, the PL intensity of the functional system increases with the amount of DOX released, thus allowing the carrier to be monitored and tracked by the change in PL intensity. A MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay showed the good biocompatibility of SrMoO4:Ln3+ hollow spheres, indicating the potential application of this kind of material in biomedicine and other fields.
Co-reporter:Yan Wang, Shili Gai, Chunxia Li, Fei He, Milin Zhang, Yongde Yan, Piaoping Yang
Electrochimica Acta 2013 90() pp: 673-681
Publication Date(Web):
DOI:10.1016/j.electacta.2012.11.136
Co-reporter:Na Niu, Fei He, Shili Gai, Chunxia Li, Xiao Zhang, Shaohua Huang and Piaoping Yang
Journal of Materials Chemistry A 2012 vol. 22(Issue 40) pp:21613-21623
Publication Date(Web):29 Aug 2012
DOI:10.1039/C2JM34653B
Pure hexagonal NaYF4:Yb3+,Ln3+ (Ln3+ = Er3+, Tm3+, Ho3+) crystals were obtained for the first time through a facile microwave (MW) reflux method at relatively low temperature (160 °C) and atmospheric pressure within only 50 min. By controllably increasing the NH4F content in the ethylene glycol (EG) solvent, the phase of as-prepared NaYF4:Yb3+,Ln3+ gradually transforms from cubic to hexagonal. Correspondingly, the up-conversion (UC) emission intensities of hexagonal NaYF4:Yb3+,Ln3+ (Ln3+ = Er3+, Tm3+, Ho3+) are increased by 10–12 times compared to those of the cubic phase. A possible growth mechanism for the phase transformation under these MW conditions has been proposed. Moreover, for the first time, we introduced Bi3+ ion into β-NaYF4:20%Yb3+,2%Ln3+ crystals. As expected, the UC emission of β-NaYF4:Yb3+,Ln3+,Bi3+ are about 10–40 times higher than those of Bi3+ free samples. It is found that tri-doping of Bi3+ doesn't change the basic emission of Ln3+ ions. XRD results gives evidence that tri-doping of Bi3+ ions can tailor the local crystal field and dissociate the Yb3+ and Ln3+ ion clusters, which is the main reason for the UC enhancement. This designed MW reflux method for the synthesis of β-NaYF4:20%Yb3+,2%Ln3+ can be applied to prepare other rare earth fluorides. The markedly enhanced UC luminescence through Bi3+ doping also provides an effective way to gain very bright UC emission.
Co-reporter:Shaohua Huang, Jie Xu, Zhenguo Zhang, Xiao Zhang, Liuzhen Wang, Shili Gai, Fei He, Na Niu, Milin Zhang and Piaoping Yang
Journal of Materials Chemistry A 2012 vol. 22(Issue 31) pp:16136-16144
Publication Date(Web):11 Jun 2012
DOI:10.1039/C2JM32412A
In the present paper, we first demonstrate a facile and rapid precipitation process to fabricate Y(OH)3 with tailored well-defined shapes and excellent uniformity in the presence of sodium citrate. The morphologies and sizes of the products can be controlled by simply tuning the sodium citrate amounts, the reaction temperature, and the amount of NaOH. After calcination, the Y(OH)3 precursors were easily converted to pure Y2O3 with no obvious change in morphology. The phases, morphologies, sizes as well as up-conversion (UC) photoluminescence of as-prepared products were well characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra, respectively. The UC emission properties of the prepared Y2O3:Yb3+/Ln3+(Ln = Er, Tm and Ho) were investigated in detail. Under 980 nm NIR excitation, the emission intensity and the corresponding luminescent colors of Y2O3:Yb3+/Ln3+ (Ln = Er, Tm and Ho) could be precisely modulated by changing the doping concentration of Yb3+ ions. Furthermore, the experimental results also reveal that the optical properties of the Y2O3:1%Yb3+/1%Ho3+ phosphors with different morphologies are strongly dependent on their morphologies and sizes.
Co-reporter:Na Niu, Piaoping Yang, Fei He, Xiao Zhang, Shili Gai, Chunxia Li and Jun Lin
Journal of Materials Chemistry A 2012 vol. 22(Issue 21) pp:10889-10899
Publication Date(Web):02 Apr 2012
DOI:10.1039/C2JM31256E
Well-defined one-dimensional NaLuF4:Yb3+,Er3+/Tm3+/Ho3+ microtubes and microrods were successfully prepared by a surfactant-free molten salt method for the first time. It is found that with the prolonged time, the phase of NaLuF4 transforms from cubic to hexagonal, while the morphology changes from nanoparticles to microtubes then to microrods. Moreover, upon 980 nm laser diode (LD) excitation, white up-conversion (UC) light was successfully achieved by properly tuning the sensitizer (Yb3+) concentration in the host matrix. The relative emission intensities of different emission colors in Yb3+/Er3+, Yb3+/Tm3+, and Yb3+/Ho3+ doped β-NaLuF4 can be precisely adjusted in a broad range by tuning the Yb3+ doping concentration. Consequently, effective UC emissions with multicolors and a strong white light can be realized in β-NaLuF4:Yb3+/Er3+/Tm3+, and β-NaLuF4:Yb3+/Tm3+/Ho3+ structures by the appropriate control of the emission intensity balance for the three blue, green, and red basic colors. UC mechanisms in the co-doping and tri-doping β-NaLuF4 samples were analyzed in detail based on the emission spectra and the plot of luminescence intensity to pump power. The as-obtained abundant luminescence colors in a much wide region contribute themselves great potential applications in various fields. Furthermore, the paper also provides an effective and facile approach to gain a desired color by manipulating the sensitizer concentration.
Co-reporter:Xingbo Li ; Shili Gai ; Chunxia Li ; Dong Wang ; Na Niu ; Fei He
Inorganic Chemistry 2012 Volume 51(Issue 7) pp:3963-3971
Publication Date(Web):March 12, 2012
DOI:10.1021/ic200925v
Three types of high-quality, monodisperse lanthanide fluoride colloidal nanocrystals (NCs) including LnF3 (Ln = La–Pr), NaLnF4 (Ln = Sm–Er), and Na5Ln9F32 (Ln = Tm–Lu) with two crystal phases (hexagonal and cubic) and a rich variety of morphologies have been synthesized in high boiling organic solvents oleic acid and 1-octadecene, via a thermal decomposition pathway. The as-synthesized NCs were well characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL) spectra, respectively. It is found that the as-synthesized NCs consist of monodisperse nanoparticles with diverse shapes and narrow size distribution, which can easily disperse in nonpolar cyclohexane solvent. Additionally, a possible mechanism of NC nucleation and growth has been proposed. The results reveal that the formation of monodisperse NCs closely correlates with the inherent nature of lanthanide series from La to Lu. Under 980 nm NIR excitation, as-synthesized Yb3+/Ln3+ (Ln = Er, Tm, Ho)-doped NaGdF4 and Na5Lu9F32 colloidal NCs show the respective characteristic up-conversion (UC) emissions of Er3+, Tm3+, and Ho3+, which are promising for applications in biolabels, bioimaging, displays, and other optical technologies.
Co-reporter:Xiao Zhang, Piaoping Yang, Dong Wang, Jie Xu, Chunxia Li, Shili Gai, and Jun Lin
Crystal Growth & Design 2012 Volume 12(Issue 1) pp:306-312
Publication Date(Web):November 23, 2011
DOI:10.1021/cg201091u
One-dimensional La(OH)3:Ln3+ (Ln = Yb/Er, Yb/Tm, Yb/Ho) microrods have been successfully synthesized using molten composite-hydroxide (NaOH/KOH) as a solvent. La2O3:Ln3+ nanostructures with retained striplike shape were achieved by a subsequent annealing process. The phase, structure, morphology, and fluorescent properties have been well investigated by various techniques. It is found that the reaction time plays a key role in confining the growth of the microrods. Both La(OH)3:Ln3+ and La2O3:Ln3+ nanostructures have rodlike shapes with a typical width of 50–400 nm. The up-conversion (UC) photoluminescence (PL) properties of the samples have been studied in detail. Under 980 nm laser excitation, both La(OH)3:Ln3+ and La2O3:Ln3+ microrods exhibit the characteristic emissions of Er3+, Tm3+, and Ho3+ and give green, blue, and blackish green emission colors, respectively. Additionally, the doping concentration of Yb3+ has been optimized by fixing the Er3+ concentration. It should be noted that the up-conversion emission of La2O3:Er3+ microrods can be significantly improved in comparison with that of their bulk counterpart under the same excitation conditions.
Co-reporter:Shaohua Huang, Xiao Zhang, Liuzhen Wang, Ling Bai, Jie Xu, Chunxia Li and Piaoping Yang
Dalton Transactions 2012 vol. 41(Issue 18) pp:5634-5642
Publication Date(Web):22 Feb 2012
DOI:10.1039/C2DT30221G
Yttrium tungstate precursors with novel 3D hierarchical architectures assembled from nanosheet building blocks were successfully synthesized by a hydrothermal method with the assistance of sodium dodecyl benzenesulfonate (SDBS). After calcination, the precursors were easily converted to Y2(WO4)3 without an obvious change in morphology. The as-prepared precursors and Y2(WO4)3 were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra, respectively. The results reveal that the morphology and dimensions of the as-prepared precursors can be effectively tuned by altering the amounts of organic SDBS and the reaction time, and the possible formation mechanism was also proposed. Upon ultraviolet (UV) excitation, the emission of Y2(WO4)3:x mol% Eu3+ microcrystals can be tuned from white to red, and the doping concentration of Eu3+ has been optimized. Furthermore, the up-conversion (UC) luminescence properties as well as the emission mechanisms of Y2(WO4)3:Yb3+/Ln3+ (Ln = Er, Tm, Ho) microcrystals were systematically investigated, which show green (Er3+, 4S3/2, 2H11/2 → 4I15/2), blue (Tm3+, 1G4 → 3H6) and yellow (Ho3+, 5S2 → 5I8) luminescence under 980 nm NIR excitation. Moreover, the doping concentration of the Yb3+ has been optimized under a fixed concentration of Er3+ for the UC emission of Y2(WO4)3:Yb3+/Er3+.
Co-reporter:Shili Gai, Piaoping Yang, Ping'an Ma, Liuzhen Wang, Chunxia Li, Milin Zhang and Lin Jun
Dalton Transactions 2012 vol. 41(Issue 15) pp:4511-4516
Publication Date(Web):29 Feb 2012
DOI:10.1039/C2DT11552B
A family of mesoporous silica microspheres with fibrous morphology and different particle sizes ranging from about 400 to 900 nm has been successfully synthesized through a facile self-assembly process. The structural, morphological, and textural properties of the samples were well characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), N2 adsorption/desorption, and thermal gravimetry (TG). The results reveal that this silica-based mesoporous material exhibits excellent physical properties, including a fibrous spherical morphology, good thermal stability, large pore volume, high specific surface area and narrow size distribution. Additionally, the size and textural properties can be tuned by altering the silica precursor/template molar ratio. The formation and the self-assembly evolution process have also been proposed. The obtained materials were further used as a drug delivery carrier to investigate the in vitro drug release properties using doxorubicin (DOX) as a representative model drug. It was found that this kind of silica exhibits good biocompatibility and obvious sustained drug release properties, suggesting its potential application in biological fields.
Co-reporter:Shaohua Huang, Dong Wang, Chunxia Li, Liuzhen Wang, Xiao Zhang, Yan Wan and Piaoping Yang
CrystEngComm 2012 vol. 14(Issue 6) pp:2235-2244
Publication Date(Web):25 Jan 2012
DOI:10.1039/C2CE06450B
In the present paper, NaLa(WO4)2 microcrystals with diverse morphologies, sizes and dimensions have been synthesized via a mild and controllable hydrothermal process using polyvinylpyrrolidone (PVP) as surfactant. The phases, morphologies, sizes, and photoluminescent properties of the as-prepared products were well characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra, respectively. The results indicate that the phase, morphology, and size of the NaLa(WO4)2 microcrystals can be tuned in a controlled manner by altering the amount of PVP, pH value of the initial solution, and the reaction time. The crystal growth was thoroughly investigated, and a possible formation mechanism was proposed. It is expected that the synthetic strategy can be extended to controllable synthesis of other types of microcrystals as well. Upon ultraviolet (UV) excitation, the NaLa(WO4)2:Ln3+ (Ln = Eu, Tb) microcrystals exhibit bright red (Eu3+, 5D0 → 7F2) and green (Tb3+, 5D4 → 7F5) luminescence. The dependence of NaLa(WO4)2:Tb3+ luminescence intensity on different morphologies has been investigated in detail. Furthermore, the up-conversion (UC) luminescent properties as well as the emission mechanisms of NaLa(WO4)2:Yb3+/Ln3+ (Ln = Er, Tm, Ho) microcrystals were systematically investigated, which show respective green (Er3+, 4S3/2,2H11/2 → 4I15/2), blue (Tm3+, 1G4 → 3H6) and yellow (Ho3+, 5S2 → 5I8) luminescence under 980 nm NIR excitation.
Co-reporter:Shili Gai, Guixin Yang, Xingbo Li, Chunxia Li, Yunlu Dai, Fei He and Piaoping Yang
Dalton Transactions 2012 vol. 41(Issue 38) pp:11716-11724
Publication Date(Web):14 Aug 2012
DOI:10.1039/C2DT30954H
Monodisperse rare earth (RE) fluoride colloidal nanocrystals (NCs) including REF3 (RE = La, Pr, Nd), NaREF4 (RE = Sm–Ho, Y) and Na5RE9F32 (RE = Er, Yb, Lu) have been successfully synthesized by a facile one-step method using oleic acid as surfactant and 1-octadecene as solvent. The phase, morphology, size, and photoluminescence properties of as-synthesized NCs were well investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL) spectra. The results reveal that the as-synthesized NCs consist of monodisperse colloidal NCs with narrow size distribution, which can easily disperse in non-polar cyclohexane solvent. The as-prepared NCs exhibit a rich variety of morphologies and different crystal phases (hexagonal or cubic), which may be related to the inherent natures of different rare earth ions. The possible formation mechanism of NCs with diverse architectures has been presented. In addition, representative Yb/Er, Yb/Tm, or Yb/Ho co-doped NaGdF4 and Na5Lu9F32 NCs exhibit intensive multicolor up-conversion (UC) luminescence under a single 980 nm NIR excitation, displaying potential applications in bioimaging and therapy. Moreover, transparent and UC fluorescent NCs–polydimethylsiloxane (PDMS) composites with regular dimensions were also prepared by an in situ polymerization route.
Co-reporter:Na Niu, Dong Wang, Shaohua Huang, Chunxia Li, Fei He, Shili Gai, Xingbo Li and Piaoping Yang
CrystEngComm 2012 vol. 14(Issue 5) pp:1744-1752
Publication Date(Web):04 Jan 2012
DOI:10.1039/C1CE06265D
Fluorine substituted strontium hydroxyapatite doped with Tb3+ or Eu3+ ions (SrFHAp:Ln) was successfully synthesized via an efficient and facile hydrothermal process using ethylene diamine tetraacetic acid disodium (Na2EDTA) as the chelating ligand. The as-prepared SrFHAp:Ln product was used as a drug carrier to investigate the drug storage and release properties using ibuprofen (IBU) as a model drug. X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrum (EDS), X-ray photoelectron spectra (XPS), fourier transform infrared spectroscopy (FT-IR), nitrogen adsorption/desorption, and photoluminescence spectra were employed to characterize the samples. The results reveal that the as-prepared fluorine substituted hydroxyapatites exhibit a hierarchical double-broccoli-like morphology. By tuning the pH value, Na2EDTA content, and the reaction time, SrFHAp microstructures with different morphologies and sizes have been achieved. A possible formation process of these samples based on the crystal splitting growth mechanism has also been proposed in detail. Moreover, the photoluminescence (PL) measurements indicate that the as-prepared SrFHAp:Ln samples exhibit the characteristic emissions of Tb3+ and Eu3+ even after the loading of organic drug molecules, suggesting its feasible possibility to be monitored or tracked during the drug release and disease therapy process.
Co-reporter:Dandan Han, Xiaoyan Jing, Jun Wang, Piaoping Yang, Dalei Song, Jingyuan Liu
Journal of Electroanalytical Chemistry 2012 Volume 682() pp:37-44
Publication Date(Web):15 August 2012
DOI:10.1016/j.jelechem.2012.06.016
La3+ doped NiO microspheres with porous structure were fabricated using colloidal carbon spheres as hard template via a hydrothermal method followed by calcination process. The morphologies and microstructures of the samples were examined by scanning electron microscopy (SEM), transition electron microscopy (TEM) and X-ray diffraction (XPS). The key point of the successful realization was that the La3+-doped NiO microspheres exhibited smaller feature sizes, high specific surface area (277.5 m2 g−1)and large pore volume (0.79 cm3 g−1). Electrochemical properties were characterized by cyclic voltammetry and galvanostatic charge/discharge. The microstructure observations confirmed that La3+ ions were successfully doped into the NiO spheres after heat treatment, and the porous structure was achieved. As a result, 1.5 mol% La3+-doped NiO showed a remarkable specific capacitance of 253 F g−1 (2 times higher than that of the pure NiO) and good cycling stability (34% capacity increase after 500 cycles). These results demonstrate that La3+-doped NiO composites as electrode materials have potential application for high-performance supercapacitors.Graphical abstractLa3+-doped NiO spheres with porous structures were successfully fabricated via simple hydrothermal synthesis and calcination. The La3+-doped NiO microspheres exhibit smaller feature sizes, high specific surface area (277.5 m2 g−1) and large pore volume (0.79 cm3 g−1). Significantly, compared with the pure NiO, the La3+-doped NiO spheres showed a remarkable discharge capacity (253 F g−1) and electrochemical stability due to the unique morphology and pore size distribution.Highlights► Formation of porous structure of La3+-doped NiO via a hydrothermal method. ► Exhibited high specific surface area (277.5 m2 g−1) and large pore volume (0.79 cm3 g−1) of La3+-doped NiO spheres. ► Composite has high specific capacitance (253 F g−1), and good cycling stability over 500 cycles.
Co-reporter:Shaohua Huang, Dong Wang, Yan Wang, Liuzhen Wang, Xiao Zhang, Piaoping Yang
Journal of Alloys and Compounds 2012 Volume 529() pp:140-147
Publication Date(Web):15 July 2012
DOI:10.1016/j.jallcom.2012.02.156
Novel three-dimensional (3D) flower-like NaY(WO4)2:Ln3+ (Ln = Eu, Yb/Er, Yb/Tm and Yb/Ho) microstructures with uniform shape and dimension have been prepared using Y(OH)CO3 nanospheres as sacrificial template through a hydrothermal process and followed by a subsequent heat treatment process. The whole process was carried out in aqueous condition without using any organic solvents, surfactant, or catalyst. The phase, morphology, size, and photoluminescence (PL) properties were well characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL) spectra, and kinetic decays, respectively. The results reveal that the as-prepared precursor of NaY(WO4)2:Eu3+ exhibits interesting white light emission under UV excitation. After annealing, the as-obtained 3D flower-like NaY(WO4)2:Eu3+ microstructures show exclusively red (Eu3+, 5D0 → 7F2) luminescence. Furthermore, the up-conversion (UC) luminescent properties and the emission mechanisms of NaY(WO4)2:Yb3+/Ln3+ (Ln = Er, Tm, Ho) microstructures have been systematically studied, which show respective green (Er3+, 4S3/2, 2H11/2 → 4I15/2), blue (Tm3+, 1G4 → 3H6) and yellow-green (Ho3+, 5S2 → 5I8) luminescence under 980 nm NIR excitation.Graphical abstractSelf-assembled 3D NaY(WO4)2:Ln3+ hierarchical microstructures with multicolor DC and UC luminescence were synthesized through a hydrothermal process and followed by a subsequent heat treatment process.Highlights► Novel self-assembled 3D NaY(WO4)2:Ln are prepared by a chemical conversion method without using any surfactant or catalyst. ► Under UV excitation, the precursor of NaY(WO4)2:Eu3+ exhibits interesting white light emission. ► The as-annealed NaY(WO4)2:Ln3+ architectures exhibit multicolor DC and UC luminescences. ► The possible formation mechanism is well investigated.
Co-reporter:Na Niu, Fei He, Shaohua Huang, Shili Gai, Xiao Zhang and Piaoping Yang
RSC Advances 2012 vol. 2(Issue 27) pp:10337-10344
Publication Date(Web):04 Sep 2012
DOI:10.1039/C2RA20991H
Uniform β-NaLuF4 nanorod bundles have been prepared through a facile two-step chemical conversion route without using any surfactants or capping reagents. During the process, lutetium precursors with square morphology were first prepared by a urea-assisted precipitation process, which then grew into the β-NaLuF4 crystals under a mild hydrothermal condition. Different experimental parameters were examined to investigate the growth mechanisms of the lutetium precursors and the NaLuF4 crystals. It is found that uniform hexagonal NaLuF4 nanorod bundles can be obtained via a mild hydrothermal process of 180 °C for 24 h when using 0.5 g NaF and the lutetium precursors prepared with 0.18 g urea. Moreover, the down-conversion (DC) and up-conversion (UC) luminescent properties of NaLuF4 were also investigated through doping different rare earth ions (Eu3+, Tb3+, Ce3+/Tb3+, Yb3+/Er3+, and Yb3+/Ho3+). It has been shown that the existence of Ce3+ ion can dramatically enhance the emission intensity of Ln3+ ion. And under 980 nm laser excitation, the Yb3+/Er3+ and Yb3+/Ho3+ doped NaLuF4 samples exhibit light green and yellowish green UC luminescence, respectively. This effective and low-cost chemical conversion method, combined with the novel structure and excellent optical luminescent properties of the as-prepared β-NaLuF4 nanocrystals, may endow this luminescent structure with promising potential to serve as biomedical candidates, solid-state lasers and display devices.
Co-reporter:Fei He, Na Niu, Zhenguo Zhang, Xiao Zhang, Dong Wang, Ling Bai, Shili Gai, Xingbo Li and Piaoping Yang
RSC Advances 2012 vol. 2(Issue 19) pp:7569-7577
Publication Date(Web):13 Jun 2012
DOI:10.1039/C2RA20675G
Controlled synthesis of β-NaLuF4 with uniform morphology, dimension and considerable monodispersity was designed via a gentle solvothermal process by using ethylenediamine (EDA) and ethylene glycol (EG) as the mixed solvent and NaNO3 as a mineralizer. X-ray diffraction (XRD), field scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectra (EDS) and down-conversion (DC) photoluminescence spectra were used to characterize the samples. The results indicate that the as-prepared β-NaLuF4 microcrystals can be rationally modified in phase, size and morphology by tuning the solvent constitution, NaNO3 content, and reaction time. Moreover, the crystal growth process was thoroughly discussed through a series of time-dependent experiments and a possible formation mechanism was proposed. Furthermore, the DC luminescence properties as well as the emission mechanisms of β-NaLuF4:Ln3+ (Ln = Eu, Tb and Ce/Tb) microcrystals were systematically investigated. It is found that the DC luminescence properties can be improved observably by introducing Ce3+ into the β-NaLuF4 microcrystals and the doping concentration of the Ce3+ is optimized under a fixed concentration of Tb3+. It is expected that the synthesis strategy can be applied to prepare many other types of micro- and nano-crystals as well.
Co-reporter:Shili Gai, Piaoping Yang, Ping'an Ma, Dong Wang, Chunxia Li, Xingbo Li, Na Niu and Jun Lin
Journal of Materials Chemistry A 2011 vol. 21(Issue 41) pp:16420-16426
Publication Date(Web):19 Sep 2011
DOI:10.1039/C1JM13357H
A novel, fibrous-structured bifunctional (magnetic and mesoporous) Fe3O4/silica microsphere was successfully synthesized through a simple and economical self-assembled process in which hydrophobic 9 nm-Fe3O4nanocrystals were directly used without modifications. The obtained material is performed as a drug delivery carrier to investigate the in vitro and intracellular delivery properties of doxorubicin hydrochloride (DOX). X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2adsorption/desorption, Fourier transform infrared spectroscopy (FT-IR), and superconducting quantum interference device (SQUID) were employed to characterize the composite. The results reveal that the novel composite exhibits typical mesoporous structure, narrow size distribution, good monodispersity, and superparamagnetic features. Notably, confocal laser scanning microscopy (CLSM) images indicate that the DOX-loaded sample could deliver DOX into the nuclei of HeLa cells to kill cells. Also, MTT assay confirms that the DOX-loaded sample leads to pronounced and efficient cytotoxic effects to L929 fibroblast cells, even similar to that of free DOX at high concentrations, whereas the pure material is non-toxic. Therefore, the novel material is expected to have potential application for targeted cancer therapy.
Co-reporter:Shili Gai, Piaoping Yang, Xingbo Li, Chunxia Li, Dong Wang, Yunlu Dai and Jun Lin
Journal of Materials Chemistry A 2011 vol. 21(Issue 38) pp:14610-14615
Publication Date(Web):12 Aug 2011
DOI:10.1039/C1JM12419F
Monodisperse, well-defined, and photoluminescent CeF3, CeF3:Tb3+, and CeF3:Tb3+@LaF3 core/shell nanocrystals (NCs) with small particle sizes (<15 nm) have been successfully synthesized by a high-temperature thermolysis in high boiling solvent of oleic acid (OA) and 1-octadecene (ODE). The morphology, phase, composition, and the fluorescent properties of the as-synthesized samples were well characterized by means of transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), photoluminescence (PL) spectra, and kinetic decays, respectively. It is found that the as-synthesized NCs consist of monodisperse nanoparticles with narrow size distribution, which can easily disperse in nonpolar cyclohexane solvent to form transparent colloid solutions. The CeF3, CeF3:Tb3+ and CeF3:Tb3+@LaF3 colloidal solutions show the characteristic emissions of Ce3+ 5d–4f (353 nm) and Tb3+ 5D4 → 7FJ (J = 6−3) transitions, respectively. The growth of the LaF3 shell on the CeF3:Tb3+ core NCs not only results in an increase of the average size, but significantly enhances the emission intensity and lifetime of the CeF3:Tb3+@LaF3 core/shell NCs with respect to those of CeF3:Tb3+ core NCs. Moreover, a transparent and fluorescent NCs/polydimethylsiloxane (PDMS) composite with regular dimension was also prepared by an in situpolymerization route.
Co-reporter:Xiao Zhang, Piaoping Yang, Chunxia Li, Dong Wang, Jie Xu, Shili Gai and Jun Lin
Chemical Communications 2011 vol. 47(Issue 44) pp:12143-12145
Publication Date(Web):13 Oct 2011
DOI:10.1039/C1CC15194K
Well defined, pure hexagonal-phased NaYF4:Yb3+,Er3+/Tm3+ microtubes and microrods were first prepared by a facile and mass production molten salt method without using any surfactant, which offers a new alternative in synthesizing such materials and opens the possibility to meet the increasing commercial demand.
Co-reporter:Fei He, Piaoping Yang, Dong Wang, Na Niu, Shili Gai, and Xingbo Li
Inorganic Chemistry 2011 Volume 50(Issue 9) pp:4116-4124
Publication Date(Web):April 6, 2011
DOI:10.1021/ic200155q
A self-assembly process has been designed for the controlled synthesis of β-NaGdF4 with uniform morphology, dimension, and considerable monodispersity under a gentle hydrothermal condition using sodium citrate as the chelating agent. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrum (EDS), and up-conversion (UC) photoluminescence spectra were used to characterize the samples. The results indicate that the NaGdF4 microcrystal can be rationally modified in phase, size, and morphology through tuning the pH value, sodium citrate content, and reaction time. Moreover, the hybrid process of the crystal growth and the self-assembly were thoroughly discussed, and a possible formation mechanism was proposed. Furthermore, the UC luminescence properties as well as the emission mechanisms of β-NaGdF4:17%Yb3+/3%Ln3+ (Ln = Er, Tm, Ho) microcrystals were systematically investigated. It is found that under 980 nm excitation, only limited emission bands were discovered which can be attributed to the energy gap and migration function of the Gd3+ ions in the β-NaGdF4 microcrystals. It is expected that the synthetic strategy can be applied to prepare many other types of micro- and nanocrystals as well.
Co-reporter:Fei He, Piaoping Yang, Dong Wang, Na Niu, Shili Gai, Xingbo Li and Milin Zhang
Dalton Transactions 2011 vol. 40(Issue 41) pp:11023-11030
Publication Date(Web):19 Sep 2011
DOI:10.1039/C1DT11157D
Well-defined 1D and 3D t-LaVO4:Ln (Ln = Eu3+, Dy3+, Sm3+) nanocrystals with regular and uniform shapes were synthesized through a simple hydrothermal route assisted by disodium ethylenediaminetetraacetic acid (Na2EDTA). X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), as well as kinetic decay curves were employed to characterize the samples. The results show that the reaction time, pH value of the initial solution, and Na2EDTA/La3+ molar ratio all have an important influence on the dimension and shapes of the final products. By introducing the “splitting mechanism” to the dimension and morphology evolution process from one-dimensional (1D) to three-dimensional (3D) t-LaVO4 crystals, the nucleation and crystal growth processes were well demonstrated. The Ln3+ ions doped t-LaVO4 samples exhibit respective bright red, blue-white and orange luminescence of Eu3+, Dy3+, and Sm3+ under ultraviolet excitation, and have potential application in the fields of colour display, UV laser and biomedicine. The results not only expand the knowledge of the properties of lanthanide orthovanadates luminescence, but also contribute to the principles of the crystal growth and dimension transition of this kind of inorganic material.
Co-reporter:Fei He, Piaoping Yang, Dong Wang, Chunxia Li, Na Niu, Shili Gai, and Milin Zhang
Langmuir 2011 Volume 27(Issue 9) pp:5616-5623
Publication Date(Web):April 11, 2011
DOI:10.1021/la200506q
Hollow La2O3:Ln (Ln = Yb/Er, Yb/Ho) microspheres with up-conversion (UC) luminescence properties were successfully synthesized via a facile sacrificial template method by employing carbon spheres as hard templates followed by a subsequent heating process. The structure, morphology, formation process, and fluorescent properties are well investigated by various techniques. The results indicate that the hollow La2O3:Ln microspheres can be well indexed to the hexagonal La2O3 phase. The hollow La2O3:Ln microspheres with uniform diameter of about 270 nm maintain the spherical morphology and good dispersion of the carbon spheres template. The shell of the hollow microspheres consists of numerous nanocrystals with the thickness of approximately 40 nm. Moreover, the possible formation mechanism of evolution from the carbon spheres to the amorphous precursor and to the final hollow La2O3:Ln microspheres has also been proposed. The Yb/Er and Yb/Ho codoped La2O3 hollow spheres exhibit bright up-conversion luminescence with different colors derived from different activators under the 980 nm NIR laser excitation. Furthermore, the doping concentration of the Yb3+ is optimized under fixed concentration of Er3+/Ho3+. This material may find potential applications in drug delivery, hydrogen and Li ion storage, and luminescent displays based on the uniform hollow structure, dimension, and UC luminescence properties.
Co-reporter:Fei He, Lili Feng, Piaoping Yang, Bin Liu, Shili Gai, Guixin Yang, Yunlu Dai, Jun Lin
Biomaterials (October 2016) Volume 105() pp:77-88
Publication Date(Web):October 2016
DOI:10.1016/j.biomaterials.2016.07.031
Upon near-infrared (NIR) light irradiation, the Nd3+ doping derived down-conversion luminescence (DCL) in NIR region and thermal effect are extremely fascinating in bio-imaging and photothermal therapy (PTT) fields. However, the concentration quenching induced opposite changing trend of the two properties makes it difficult to get desired DCL and thermal effect together in one single particle. In this study, we firstly designed a unique NaGdF4:0.3%Nd@NaGdF4@NaGdF4:10%Yb/1%Er@NaGdF4:10%Yb @NaNdF4:10%Yb multiple core-shell structure. Here the inert two layers (NaGdF4 and NaGdF4:10%Yb) can substantially eliminate the quenching effects, thus achieving markedly enhanced NIR-to-NIR DCL, NIR-to-Vis up-conversion luminescence (UCL), and thermal effect under a single 808 nm light excitation simultaneously. The UCL excites the attached photosensitive drug (Au25 nanoclusters) to generate singlet oxygen (1O2) for photodynamic therapy (PDT), while DCL with strong NIR emission serves as probe for sensitive deep-tissue imaging. The in vitro and in vivo experimental results demonstrate the excellent cancer inhibition efficacy of this platform due to a synergistic effect arising from the combined PTT and PDT. Furthermore, multimodal imaging including fluorescence imaging (FI), photothermal imaging (PTI), and photoacoustic imaging (PAI) has been obtained, which is used to monitor the drug delivery process, internal structure of tumor and photo-therapeutic process, thus achieving the target of imaging-guided cancer therapy.
Co-reporter:Fei He, Lili Feng, Piaoping Yang, Bin Liu, Shili Gai, Guixin Yang, Yunlu Dai, Jun Lin
Biomaterials (October 2016) Volume 105() pp:
Publication Date(Web):1 October 2016
DOI:10.1016/j.biomaterials.2016.07.031
Upon near-infrared (NIR) light irradiation, the Nd3+ doping derived down-conversion luminescence (DCL) in NIR region and thermal effect are extremely fascinating in bio-imaging and photothermal therapy (PTT) fields. However, the concentration quenching induced opposite changing trend of the two properties makes it difficult to get desired DCL and thermal effect together in one single particle. In this study, we firstly designed a unique NaGdF4:0.3%Nd@NaGdF4@NaGdF4:10%Yb/1%Er@NaGdF4:10%Yb @NaNdF4:10%Yb multiple core-shell structure. Here the inert two layers (NaGdF4 and NaGdF4:10%Yb) can substantially eliminate the quenching effects, thus achieving markedly enhanced NIR-to-NIR DCL, NIR-to-Vis up-conversion luminescence (UCL), and thermal effect under a single 808 nm light excitation simultaneously. The UCL excites the attached photosensitive drug (Au25 nanoclusters) to generate singlet oxygen (1O2) for photodynamic therapy (PDT), while DCL with strong NIR emission serves as probe for sensitive deep-tissue imaging. The in vitro and in vivo experimental results demonstrate the excellent cancer inhibition efficacy of this platform due to a synergistic effect arising from the combined PTT and PDT. Furthermore, multimodal imaging including fluorescence imaging (FI), photothermal imaging (PTI), and photoacoustic imaging (PAI) has been obtained, which is used to monitor the drug delivery process, internal structure of tumor and photo-therapeutic process, thus achieving the target of imaging-guided cancer therapy.
Co-reporter:Yurong Yang, Peng Gao, Ying Wang, Linna Sha, Xiaochen Ren, Jianjiao Zhang, Yujin Chen, Tingting Wu, Piaoping Yang, Xiaobo Li
Nano Energy (March 2017) Volume 33() pp:
Publication Date(Web):March 2017
DOI:10.1016/j.nanoen.2017.01.030
•TiO2-C composite with a Ti–C chemically bonded interface short the charger transfer path.•TiO2-C composite displayed exceptional photoelectron responses compared to TiO2/C composite without Ti–C bond.•The rate of visible-light driven photocatalytic water splitting for H2 generation of TiO2-C was about 12 times of TiO2/C composite.The construction of semiconductor composites is known a powerful method to realize the spatial separation of electrons and holes, which results in more electrons or holes dispersing on the surface, accompanying a charge transfer and further extending the region of charge depletion at the interface between these two components of the composite. However, most of them are based on a random accumulation connection of two different crystals and there are obvious empty spaces, which are formed as deplete layer to hinders the charge transfer to a large extent. In order to shorten the charger transfer path and make a direct charge transform from interface to surface, a chemically bonded interface in the composite is more reasonable. In this work, using one-dimensional TiO2-C composite nanorods with a Ti–C chemically bonded interface as a touchstone, which was prepared through a simple carbonized process, the above strategy for better semiconductor photocatalytic water splitting property has been realized.TiO2-C composite with a Ti–C chemically bonded interface can short the charger transfer path and make a direct charger transform from interface to surface. TiO2-C composite displayed exceptional photoelectron responses compared to TiO2/C composite without Ti–C bond. The rate of visible-light driven photocatalytic water splitting for H2 generation of TiO2-C was about 12 times of TiO2/C composite.
Co-reporter:Yunhua Han, Yan Wang, Shaohua Huang, Fan-Long Jin, ... Piaoping Yang
Journal of Industrial and Engineering Chemistry (25 February 2016) Volume 34() pp:269-277
Publication Date(Web):25 February 2016
DOI:10.1016/j.jiec.2015.11.021
In this work, well-defined NaLa(WO4)2 microstructures were prepared by a facile hydrothermal process in the presence of oleylamine and oleic acid as a mixed surfactant. The phase, morphology, size and luminescence properties were well characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL) spectra, and decay time, respectively. The results reveal that the morphology and size of the as-synthesized samples can be tuned by altering the reaction time and the amounts of oleic acid. A possible formation mechanism of tetragonal NaLa(WO4)2 is proposed on the basis of oleic acid amount-dependent experiments. Upon ultraviolet (UV) excitation, NaLa(WO4)2:Eu3+ and NaLa(WO4)2:Tb3+ exhibit the characteristic down-conversion emissions of Eu3+ and Tb3+. Yb3+/Er3+ and Yb3+/Tm3+ co-doped NaLa(WO4)2 samples show strong green (Er3+, 4S3/2, 2H11/2 → 4I15/2) and blue (Tm3+, 1G4 → 3H6) up-conversion emission under 980 nm laser diode excitation. Upconversion emission mechanisms of NaLa(WO4)2:Ln (Ln = Yb/Er, Yb/Tm) are also presented based on the emission spectra and the plot of luminescence intensity to pump power. It should be noted that the intensity of the upconversion emissions can be dramatically enhanced compared with sodium free tungstates, which can be attributed to the charge compensation and means the introduction of Na+ ions in WO42− causes less distortion in the crystal structure.Download high-res image (78KB)Download full-size image
Co-reporter:Jiating Xu, Mingdi Sun, Ye Kuang, Huiting Bi, Bin Liu, Dan Yang, Ruichan Lv, Shili Gai, Fei He and Piaoping Yang
Dalton Transactions 2017 - vol. 46(Issue 5) pp:NaN1501-1501
Publication Date(Web):2016/12/20
DOI:10.1039/C6DT04529D
Rare-earth-doped up-conversion nanoparticles (UCNPs), which are capable of converting infrared light to shorter-wavelength photons, have attracted worldwide attention due to their unique characteristics. However, the emission brightness of UCNPs is greatly limited by the unsatisfactory absorptivity of lanthanide ions. Herein, we adopted a novel strategy to enhance the up-conversion intensity using NIR dye IR-808 as an antenna to sensitize the core–shell–shell structured NaGdF4:Yb,Er@NaGdF4:Yb@NaNdF4:Yb UCNPs. When excited with 808 nm light, the IR-808 emitted a broadband peak, which perfectly overlapped with the absorption of Nd3+ and Yb3+ ions. Thus, the active shell of NaNdF4:Yb can efficiently capture the emitted NIR photons and transfer them to the transition layer of NaGdF4:Yb. The transition layer acted as an energy bridge to connect the active shell and up-converting zone, avoiding the energy back-transfer from the activators to Nd3+ ions. The optimized dye sensitization combined with the well-designed core–shell–shell structure tremendously enhances the NIR photon absorptivity of UCNPs and eliminates the deleterious cross-relaxation between the activators and sensitizers, eventually leading to dramatic enhancement of the up-conversion intensity. This study provides a new insight into the dye-sensitized up-conversion luminescence of rare earth-based nanoparticles and facilitates their practical applications.
Co-reporter:Jiating Xu, Dan Yang, Ruichan Lv, Bin Liu, Shili Gai, Fei He, Chunxia Li and Piaoping Yang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 35) pp:NaN5894-5894
Publication Date(Web):2016/08/09
DOI:10.1039/C6TB01677D
A nanoplatform capable of pH/thermo-coupling sensitive drug release, multimodal imaging, and synergetic antitumor therapy was designed and prepared. The core–shell structured platform consists of a dominant red up-converted luminescence (UCL) core and a copolymer P(NIPAm-MAA) gated mesoporous silica layer with functional cargos loaded inside. Due to the tri-doped Yb/Ce/Ho ions in the core and the inert shell coating, the nanoparticles show intense red UCL under NIR laser excitation. Thereafter, the emitted red light transfers energy to the conjugated photodynamic therapy (PDT) agent zinc(II)-phthalocyanine (ZnPc), which produces singlet oxygen, and the decorated carbon dots (CDs) generate an obvious photothermal effect upon 980 nm laser irradiation as well as avoiding ZnPc leakage. Notably, the thermal effect together with the acidic environment in the cancer sites induces the shrinkage of P(NIPAm-MAA), realizing targeted and controllable release of DOX. Due to the photothermal-/photodynamic-/chemo-therapy derived synergistic effect, the nanoplatform exhibits desirable tumor inhibition efficacy, as verified by both in vitro and in vivo results. In particular, the doped rare earth ions enable the product to have simultaneous UCL, magnetic resonance imaging (MRI) and computed tomography (CT) imaging properties, thus achieving the integration of diagnosis and therapy.
Co-reporter:Guixin Yang, Fei He, Ruichan Lv, Shili Gai, Ziyong Cheng, Yunlu Dai and Piaoping Yang
Dalton Transactions 2015 - vol. 44(Issue 1) pp:NaN253-253
Publication Date(Web):2014/10/17
DOI:10.1039/C4DT02425G
A facile solution-based thermal decomposition strategy, using very cheap polyisobutylene succimide (PIBSI) and paraffin oil as a surfactant and solvent, respectively, has been developed for the controllable synthesis of magnetic MnFe2O4 and CoFe2O4 nanocrystals (NCs) with high dispersibility, uniform shape, and high yield. By fine-tuning the reaction temperature and growth time, the morphology and size of MnFe2O4 and CoFe2O4 NCs can be simply regulated. It is found that the surfactant PIBSI plays a key role in the final shape of the products due to its long chain with non-polar groups, which can markedly hinder the aggregation of the NCs and thus greatly improve the stability and dispersibility of the products. The results reveal that MnFe2O4 and CoFe2O4 NCs have good biocompatibility and obvious T2 contrast enhancement effects have been achieved with the increase of iron concentration. MnFe2O4 and CoFe2O4 NCs show high longitudinal relaxivity of 165.6 and 65.143 mM−1 S−1 in aqueous solutions due to the positive signal enhancement ability of Fe3+ ions, indicating the highly potential to be used as effective T2 contrast agents for magnetic resonance imaging (MRI).
Co-reporter:Jie Xu, Shili Gai, Fei He, Na Niu, Peng Gao, Yujin Chen and Piaoping Yang
Dalton Transactions 2014 - vol. 43(Issue 30) pp:NaN11675-11675
Publication Date(Web):2014/05/07
DOI:10.1039/C4DT00686K
Reduced graphene oxide (rGO) sheet and ternary-component Ni1−xCoxAl-layered double hydroxide (Ni1−xCoxAl-LDH) hybrid composites with an interesting sandwich structure have been fabricated by an in situ growth route. The as-obtained composite displays a sandwich architecture constructed by the self-assembly of sheet-like LDH crystals on both sides of the rGO sheets. It was found that the Co content doped in Ni1−xCoxAl-LDH plays an important role in the shape and structure of the final products. When the Co doped content is 17%, the rGO/Ni0.83Co0.17Al-LDH has a high surface area (171.5 m2 g−1) and exhibits a perfect sandwich structure. In addition, this structure and morphology is favorable for a supercapacitor electrode material with a high performance. The influence of cobalt content on the electrochemical behavior of rGO/Ni1−xCoxAl-LDH has been systematically studied. The results indicate that the rGO/Ni0.83Co0.17Al-LDH composite exhibits the highest electrochemical performance, with a specific capacitance of 1902 F g−1 at 1 A g−1, and an excellent cycling stability. The markedly improved electrochemical performance is superior to undoped rGO/NiAl-LDH and can be attributed to the enhanced conductivity achieved through cobalt doping. Such composites could be used as a type of potential energy storage/conversion material for supercapacitors.
Co-reporter:Shili Gai, Piaoping Yang, Ping'an Ma, Liuzhen Wang, Chunxia Li, Milin Zhang and Lin Jun
Dalton Transactions 2012 - vol. 41(Issue 15) pp:NaN4516-4516
Publication Date(Web):2012/02/29
DOI:10.1039/C2DT11552B
A family of mesoporous silica microspheres with fibrous morphology and different particle sizes ranging from about 400 to 900 nm has been successfully synthesized through a facile self-assembly process. The structural, morphological, and textural properties of the samples were well characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), N2 adsorption/desorption, and thermal gravimetry (TG). The results reveal that this silica-based mesoporous material exhibits excellent physical properties, including a fibrous spherical morphology, good thermal stability, large pore volume, high specific surface area and narrow size distribution. Additionally, the size and textural properties can be tuned by altering the silica precursor/template molar ratio. The formation and the self-assembly evolution process have also been proposed. The obtained materials were further used as a drug delivery carrier to investigate the in vitro drug release properties using doxorubicin (DOX) as a representative model drug. It was found that this kind of silica exhibits good biocompatibility and obvious sustained drug release properties, suggesting its potential application in biological fields.
Co-reporter:Shili Gai, Guixin Yang, Xingbo Li, Chunxia Li, Yunlu Dai, Fei He and Piaoping Yang
Dalton Transactions 2012 - vol. 41(Issue 38) pp:NaN11724-11724
Publication Date(Web):2012/08/14
DOI:10.1039/C2DT30954H
Monodisperse rare earth (RE) fluoride colloidal nanocrystals (NCs) including REF3 (RE = La, Pr, Nd), NaREF4 (RE = Sm–Ho, Y) and Na5RE9F32 (RE = Er, Yb, Lu) have been successfully synthesized by a facile one-step method using oleic acid as surfactant and 1-octadecene as solvent. The phase, morphology, size, and photoluminescence properties of as-synthesized NCs were well investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL) spectra. The results reveal that the as-synthesized NCs consist of monodisperse colloidal NCs with narrow size distribution, which can easily disperse in non-polar cyclohexane solvent. The as-prepared NCs exhibit a rich variety of morphologies and different crystal phases (hexagonal or cubic), which may be related to the inherent natures of different rare earth ions. The possible formation mechanism of NCs with diverse architectures has been presented. In addition, representative Yb/Er, Yb/Tm, or Yb/Ho co-doped NaGdF4 and Na5Lu9F32 NCs exhibit intensive multicolor up-conversion (UC) luminescence under a single 980 nm NIR excitation, displaying potential applications in bioimaging and therapy. Moreover, transparent and UC fluorescent NCs–polydimethylsiloxane (PDMS) composites with regular dimensions were also prepared by an in situ polymerization route.
Co-reporter:Na Niu, Piaoping Yang, Fei He, Xiao Zhang, Shili Gai, Chunxia Li and Jun Lin
Journal of Materials Chemistry A 2012 - vol. 22(Issue 21) pp:NaN10899-10899
Publication Date(Web):2012/04/02
DOI:10.1039/C2JM31256E
Well-defined one-dimensional NaLuF4:Yb3+,Er3+/Tm3+/Ho3+ microtubes and microrods were successfully prepared by a surfactant-free molten salt method for the first time. It is found that with the prolonged time, the phase of NaLuF4 transforms from cubic to hexagonal, while the morphology changes from nanoparticles to microtubes then to microrods. Moreover, upon 980 nm laser diode (LD) excitation, white up-conversion (UC) light was successfully achieved by properly tuning the sensitizer (Yb3+) concentration in the host matrix. The relative emission intensities of different emission colors in Yb3+/Er3+, Yb3+/Tm3+, and Yb3+/Ho3+ doped β-NaLuF4 can be precisely adjusted in a broad range by tuning the Yb3+ doping concentration. Consequently, effective UC emissions with multicolors and a strong white light can be realized in β-NaLuF4:Yb3+/Er3+/Tm3+, and β-NaLuF4:Yb3+/Tm3+/Ho3+ structures by the appropriate control of the emission intensity balance for the three blue, green, and red basic colors. UC mechanisms in the co-doping and tri-doping β-NaLuF4 samples were analyzed in detail based on the emission spectra and the plot of luminescence intensity to pump power. The as-obtained abundant luminescence colors in a much wide region contribute themselves great potential applications in various fields. Furthermore, the paper also provides an effective and facile approach to gain a desired color by manipulating the sensitizer concentration.
Co-reporter:Shaohua Huang, Jie Xu, Zhenguo Zhang, Xiao Zhang, Liuzhen Wang, Shili Gai, Fei He, Na Niu, Milin Zhang and Piaoping Yang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 31) pp:
Publication Date(Web):
DOI:10.1039/C2JM32412A
Co-reporter:Yan Wang, Shili Gai, Na Niu, Fei He and Piaoping Yang
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 39) pp:NaN16805-16805
Publication Date(Web):2013/08/08
DOI:10.1039/C3CP52813H
In this paper, NaYF4 microcrystals with a variety of morphologies, such as microsphere, hexagonal prism, microtube and octahedron shapes, have been synthesized via a hydrothermal method using sodium poly(4-styrenesulfonate) (PSS) as a template. The structural and kinetic factors that govern the phase and shape evolution of NaYF4 microcrystals have been systematically studied. And the influence of reaction time, pH values, fluoride sources and reaction temperature on the phase and shape of the as-synthesized NaYF4 was systematically investigated and discussed. It is found that PSS can be employed as a shape modifier, which is responsible for the shape evolution. The possible formation mechanism for the products with various architectures has been presented. The up-conversion (UC) properties of Yb3+/Ho3+, Yb3+/Er3+ or Yb3+/Tm3+ codoped NaYF4 samples were studied. In particular, the luminescence intensity can be markedly enhanced by Li+ doping, the related mechanism has been discussed. Furthermore, a systematic study on the UC emissions of Yb3+/Tm3+ codoped NaYF4 samples with microsphere, hexagonal prism, microtube and octahedron shapes has shown that the optical properties of these phosphors are strongly dependent on their morphologies and sizes. This study would be suggestive for the precisely controlled growth of inorganic crystals, especially for those rare earth fluoride compounds.
Co-reporter:Shili Gai, Piaoping Yang, Ping'an Ma, Dong Wang, Chunxia Li, Xingbo Li, Na Niu and Jun Lin
Journal of Materials Chemistry A 2011 - vol. 21(Issue 41) pp:NaN16426-16426
Publication Date(Web):2011/09/19
DOI:10.1039/C1JM13357H
A novel, fibrous-structured bifunctional (magnetic and mesoporous) Fe3O4/silica microsphere was successfully synthesized through a simple and economical self-assembled process in which hydrophobic 9 nm-Fe3O4nanocrystals were directly used without modifications. The obtained material is performed as a drug delivery carrier to investigate the in vitro and intracellular delivery properties of doxorubicin hydrochloride (DOX). X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2adsorption/desorption, Fourier transform infrared spectroscopy (FT-IR), and superconducting quantum interference device (SQUID) were employed to characterize the composite. The results reveal that the novel composite exhibits typical mesoporous structure, narrow size distribution, good monodispersity, and superparamagnetic features. Notably, confocal laser scanning microscopy (CLSM) images indicate that the DOX-loaded sample could deliver DOX into the nuclei of HeLa cells to kill cells. Also, MTT assay confirms that the DOX-loaded sample leads to pronounced and efficient cytotoxic effects to L929 fibroblast cells, even similar to that of free DOX at high concentrations, whereas the pure material is non-toxic. Therefore, the novel material is expected to have potential application for targeted cancer therapy.
Co-reporter:Shili Gai, Piaoping Yang, Xingbo Li, Chunxia Li, Dong Wang, Yunlu Dai and Jun Lin
Journal of Materials Chemistry A 2011 - vol. 21(Issue 38) pp:NaN14615-14615
Publication Date(Web):2011/08/12
DOI:10.1039/C1JM12419F
Monodisperse, well-defined, and photoluminescent CeF3, CeF3:Tb3+, and CeF3:Tb3+@LaF3 core/shell nanocrystals (NCs) with small particle sizes (<15 nm) have been successfully synthesized by a high-temperature thermolysis in high boiling solvent of oleic acid (OA) and 1-octadecene (ODE). The morphology, phase, composition, and the fluorescent properties of the as-synthesized samples were well characterized by means of transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), photoluminescence (PL) spectra, and kinetic decays, respectively. It is found that the as-synthesized NCs consist of monodisperse nanoparticles with narrow size distribution, which can easily disperse in nonpolar cyclohexane solvent to form transparent colloid solutions. The CeF3, CeF3:Tb3+ and CeF3:Tb3+@LaF3 colloidal solutions show the characteristic emissions of Ce3+ 5d–4f (353 nm) and Tb3+ 5D4 → 7FJ (J = 6−3) transitions, respectively. The growth of the LaF3 shell on the CeF3:Tb3+ core NCs not only results in an increase of the average size, but significantly enhances the emission intensity and lifetime of the CeF3:Tb3+@LaF3 core/shell NCs with respect to those of CeF3:Tb3+ core NCs. Moreover, a transparent and fluorescent NCs/polydimethylsiloxane (PDMS) composite with regular dimension was also prepared by an in situpolymerization route.
Co-reporter:Na Niu, Fei He, Shili Gai, Chunxia Li, Xiao Zhang, Shaohua Huang and Piaoping Yang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 40) pp:NaN21623-21623
Publication Date(Web):2012/08/29
DOI:10.1039/C2JM34653B
Pure hexagonal NaYF4:Yb3+,Ln3+ (Ln3+ = Er3+, Tm3+, Ho3+) crystals were obtained for the first time through a facile microwave (MW) reflux method at relatively low temperature (160 °C) and atmospheric pressure within only 50 min. By controllably increasing the NH4F content in the ethylene glycol (EG) solvent, the phase of as-prepared NaYF4:Yb3+,Ln3+ gradually transforms from cubic to hexagonal. Correspondingly, the up-conversion (UC) emission intensities of hexagonal NaYF4:Yb3+,Ln3+ (Ln3+ = Er3+, Tm3+, Ho3+) are increased by 10–12 times compared to those of the cubic phase. A possible growth mechanism for the phase transformation under these MW conditions has been proposed. Moreover, for the first time, we introduced Bi3+ ion into β-NaYF4:20%Yb3+,2%Ln3+ crystals. As expected, the UC emission of β-NaYF4:Yb3+,Ln3+,Bi3+ are about 10–40 times higher than those of Bi3+ free samples. It is found that tri-doping of Bi3+ doesn't change the basic emission of Ln3+ ions. XRD results gives evidence that tri-doping of Bi3+ ions can tailor the local crystal field and dissociate the Yb3+ and Ln3+ ion clusters, which is the main reason for the UC enhancement. This designed MW reflux method for the synthesis of β-NaYF4:20%Yb3+,2%Ln3+ can be applied to prepare other rare earth fluorides. The markedly enhanced UC luminescence through Bi3+ doping also provides an effective way to gain very bright UC emission.
Co-reporter:Yan Wang, Piaoping Yang, Ping'an Ma, Fengyu Qu, Shili Gai, Na Niu, Fei He and Jun Lin
Journal of Materials Chemistry A 2013 - vol. 1(Issue 15) pp:NaN2065-2065
Publication Date(Web):2013/01/31
DOI:10.1039/C3TB00377A
In this study, a facile and mild one-pot approach was employed to prepare hollow-structured SrMoO4 spheres using soluble sodium poly(4-styrenesulfonate) (PSS) as a soft template. It is found that the as-prepared product exhibits hollow spherical morphology, good dispersity, and narrow size distribution. The formation mechanism has also been proposed. Tunable multicolor and bright white up-conversion (UC) emissions were successfully realized by precisely adjusting the doping sensitizer (Yb3+) and activator (Tm3+, Ho3+, and Tm3+/Ho3+) concentration in the host matrix. MTT assay shows the good biocompatibility of SrMoO4:Yb3+/Tm3+ hollow spheres, which were used as an anti-cancer drug carrier to evaluate the loading and controlled release behavior by selecting doxorubicin hydrochloride (DOX) as a model drug. Drug release tests reveal a sustained drug release behavior and especially the UC emission intensities of the drug loaded system increase with the released amount of DOX, indicating that the extent of drug release can be monitored or tracked by the change in emission intensity. Moreover, the in vitro cytotoxic effect against SKOV3 ovarian cancer cells of the DOX-loaded carrier was investigated and the endocytosis process of drug-loaded microspheres was studied using confocal laser scanning microscopy (CLSM) and flow cytometry. Considering the good biocompatibility, high drug loading amount and obvious sustained drug release properties, the hollow microspheres are highly promising in biological areas.
Co-reporter:Rumin Li, Lei Li, Yunhua Han, Shili Gai, Fei He and Piaoping Yang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 15) pp:NaN2135-2135
Publication Date(Web):2014/01/24
DOI:10.1039/C3TB21718C
Gd2O3:Ln@mSiO2 hollow nanospheres (Gd2O3:Ln hollow spheres coated by a mesoporous silica layer) were successfully synthesized through a self-template method using Gd(OH)CO3 as template to form hollow precursors (named HPs), which involved the incorporation of the rare earth compound into the interior of the hydrophilic carbon shell, followed by coating with a mesoporous silica shell, and subsequent calcination in air. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric and differential thermal analyses (TG-DTA), photoluminescence spectroscopy, kinetic decays as well as N2 adsorption/desorption were employed to characterize the composites. The results indicate that the uniform Gd2O3:Ln@mSiO2 composite with the particle size around 300 nm maintains the spherical morphology and good dispersibility of the precursor. Interestingly, the composite has a double-shell structure including an inner shell of Gd2O3 and an outer shell of mesoporous silica. Moreover, they also exhibit bright red (Eu3+, 5D0 → 7F2) down-conversion (DC) emission and characteristic up-conversion (UC) emissions of Yb3+/Er3+. Under beam excitation, the hollow structured sample emits, which should have potential applications in biomedicine and other fields.
Co-reporter:Jie Xu, Shili Gai, Ping'an Ma, Yunlu Dai, Guixin Yang, Fei He and Piaoping Yang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 13) pp:NaN1801-1801
Publication Date(Web):2014/01/13
DOI:10.1039/C3TB21465F
In this study, uniform gadolinium fluoride microspheres with controllable phases and structures have been synthesized for the first time by a facile ion exchange process using Gd(OH)CO3 solid microspheres as precursors. It is found that the as-synthesized NaxGdyFx+3y samples, including orthorhombic GdF3, cubic Na5Gd9F32 and hexagonal NaGdF4, all consist of well dispersed microspheres with mesopores. After the conversion process, the products mainly inherit the size and shape of the precursors. Moreover, the used ethylene glycol (EG) plays a key role in the phase and structure of the final NaxGdyFx+3y mesoporous spheres by impacting the etching and ion exchange process. Based on the time-dependent experiments of gadolinium fluorides, the possible formation mechanism is discussed in detail. Under 273 nm UV excitation, NaxGdyFx+3y:2% Eu3+ shows bright red emissions due to efficient energy transfer from Gd3+ to Eu3+. NaxGdyFx+3y:17% Yb3+/3% Er3+ exhibits the characteristic up-conversion (UC) emissions of Er3+. It is noted that the highest DC and UC emission intensities of NaGdF4:Ln should be due to the hexagonal phase. The fluorescent NaxGdyFx+3y mesoporous microspheres show obvious drug (doxorubicin hydrochloride, DOX) storage/release properties and good biocompatibility, suggesting their potential application in biomedical fields.
Co-reporter:Arif Gulzar, Shili Gai, Piaoping Yang, Chunxia Li, Mohd Bismillah Ansari and Jun Lin
Journal of Materials Chemistry A 2015 - vol. 3(Issue 44) pp:NaN8622-8622
Publication Date(Web):2015/09/03
DOI:10.1039/C5TB00757G
In the last decade, using polymer and mesoporous silica materials as efficient drug delivery carriers has attracted great attention. Although the development and application of them involves some inevitable barriers, such as chronic toxicities, long-term stability, understanding of the biological fate and physiochemical properties, biodistribution, effect in the biological environment, circulation properties and targeting efficacy in vivo. The construction of stimuli responsive drug carriers using biologically safe materials, followed by hydrophilic modification, bioconjugation, targeting functionalization, and detailed safety analysis in small/large animal models may be the best way to overcome these barriers. Huge progress has been made in stimuli responsive drug delivery systems based on polymer and mesoporous silica materials, mainly including pH-, thermo-, light-, enzyme-, redox-, magnetic field- and ultrasound-responsive drug delivery systems, all of which are highlighted in this review.
Co-reporter:Jiating Xu, Ruichan Lv, Shaokang Du, Shili Gai, Fei He, Dan Yang and Piaoping Yang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 23) pp:NaN4146-4146
Publication Date(Web):2016/05/10
DOI:10.1039/C6TB00714G
To enhance the total emission intensity, particularly the red emission of Yb,Er co-doped nanoparticles for red light activated photodynamic therapy (PDT), we doped Mn2+ ions into the NaGdF4:Yb,Er core, and subsequently coated the NaGdF4:Yb active shell to fabricate core–shell structured, up-conversion nanoparticles of NaGdF4:Yb,Er,Mn@NaGdF4:Yb (abbreviated as UCNPs). A novel and facile encapsulation method with gelatin has been proposed to transfer oleic acid (OA) stabilized UCNPs into an aqueous solution and simultaneously decorate zinc phthalocyanine (ZnPc) photosensitizer molecules. In the encapsulation process, ZnPc molecules are wrapped in the interlaced net structure of the peptide chain from gelatin, forming the UCNPs@gel–ZnPc nanocomposite. The nanoplatform has high emission intensity and excellent biocompatibility, as was expected. More importantly, the enhanced red emission of UCNPs has significant overlap with the UV absorbance of ZnPc; therefore, it can effectively activate the sensitizer to produce a large amount of singlet oxygen reactive oxygen species (ROS, 1O2) to kill cancer cells, which has evidently been verified by the in vitro results. Combined with the inherent up-conversion luminescence (UCL) imaging properties, this UCNPs@gel–ZnPc nanoplatform could have potential application in PDT and imaging fields.
Co-reporter:Yan Wang, Shili Gai, Na Niu, Fei He and Piaoping Yang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 32) pp:NaN9091-9091
Publication Date(Web):2013/05/21
DOI:10.1039/C3TA11161J
A novel structured reduced graphene oxide/Ni(OH)2 (rGO/Ni(OH)2) hybrid composite with enhanced electrochemical performance was prepared by wrapping β-Ni(OH)2 hollow microspheres in rGO sheets via a facile solvothermal route, using poly(L-lysine) (PLL) as reductant and ethylene glycol (EG) as coupling agent. The structural, morphological and electrochemical properties of the composite were well examined. The results show that single-crystalline β-Ni(OH)2 hollow microspheres are enveloped in rGO sheets after thermal treatment in the hybrid composite, which exhibits a high specific capacitance of 1551.8 F g−1 at a current density of 2.67 A g−1 and a capacity retention of 102% after 2000 cycles. Notably, in comparison with pure β-Ni(OH)2 hollow microspheres and the simple mixture (mixture of rGO and Ni(OH)2 spheres), the rGO/β-Ni(OH)2 composite exhibited superior electrochemical properties, which may be due to the wrapped electrically conducting graphene sheets and the unique three-dimensional (3D) structure of the composite. The rational design, interesting structure and the ideal electrochemical performance of this graphene-based composite suggest its potential applications in high energy storage systems.
Co-reporter:Lei Li, Rumin Li, Shili Gai, Fei He and Piaoping Yang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 23) pp:NaN8765-8765
Publication Date(Web):2014/04/10
DOI:10.1039/C4TA01186D
A novel core–shell structured Fe3O4@C@Ni–Al LDH composite containing a carbon-coated Fe3O4 magnetic core and a layered double hydroxide (LDH) has been successfully prepared by a combination of the hydrothermal method and a facile in situ growth process. The Fe3O4@C@Ni–Al LDH microspheres were characterized by X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM), high-resolution transmission electron microscopy (HRTEM), Fourier transformed infrared (FT-IR), X-ray photoelectron spectra (XPS), and N2 adsorption/desorption methods. Owing to the unique layered feature, the composite displays core–shell structure with flower-like morphology, ultra-high surface area (792 m2 g−1) and specific pore size distribution. Moreover, the as-synthesized Fe3O4@C@Ni–Al LDH microsphere as an electrode material was fabricated into a supercapacitor and characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge measurements. It turned out that the Fe3O4@C@Ni–Al LDH exhibits specific capacitance of 767.6 F g−1, good rate capability, and remarkable cycling stability (92% after 1000 cycling). Therefore, such a novel synthetic route to assemble the high-performance electrochemical capacitor may open a new strategy to prepare other materials with largely enhanced electrochemical properties, which can be of great promise in energy storage device applications.
Co-reporter:Wang Yan, Fei He, Shili Gai, Peng Gao, Yujin Chen and Piaoping Yang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 10) pp:NaN3612-3612
Publication Date(Web):2013/12/11
DOI:10.1039/C3TA14718E
In this study, TiO2 hollow microspheres with high photocatalytic activity were prepared by simply optimizing the ratio of the as-used templates (poly(4-styrenesulfonate) (PSS) and triblock copolymer P123). In particular, a novel three-dimensional (3D) reduced graphene oxide/TiO2 (rGO/TiO2) hybrid composite was for the first time prepared by wrapping TiO2 hollow microspheres with rGO sheets via a facile solvothermal route using poly(L-lysine) (PLL) and ethylene glycol (EG) as coupling agents. The structural, morphological and photocatalytic properties of the as-synthesized products were examined. It is found that rGO/TiO2 hybrid composite exhibits markedly enhanced photocatalytic performance in comparison with pure TiO2 hollow microspheres and the simple mixture of rGO and TiO2 spheres. The rational design, interesting structure and ideal photocatalytic performance of this graphene-based composite show great promise in diverse fields.
Co-reporter:Lei Li, Rumin Li, Shili Gai, Peng Gao, Fei He, Milin Zhang, Yujin Chen and Piaoping Yang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 30) pp:NaN15649-15649
Publication Date(Web):2015/06/23
DOI:10.1039/C5TA03224E
In this contribution, we present a novel and rational strategy for preparing hierarchical porous CNTs@NCS@MnO2 core–shell composites via a facile in situ chemical polymerization coating method, followed by a hydrothermal process. An intermediate nitrogen-doped carbon shell (NCS) with mesoporous structure and favorable chemical durability is obtained by utilizing resorcinol–formaldehyde resin as the carbon source and L-cysteine as the nitrogen source. Benefiting from a unique structure and considerable combination, the composites exhibit a highly comprehensive electrochemical performance: high specific capacitance (312.5 F g−1 at a current density of 1 A g−1), good rate capability (76.8% retention with the charge–discharge rate increasing from 1 A g−1 to 10 A g−1), superior reversibility and cycling stability (92.7% capacitance retention after 4000 cycles at 8 A g−1). In order to increase the energy density and voltage window, an asymmetric supercapacitor (ASC) was assembled using CNTs@NCS@MnO2 and activated carbon (AC) as the positive and negative electrodes, respectively. The as-fabricated asymmetric supercapacitor achieved a high specific capacitance with a stable operating voltage of 1.8 V and a maximum energy density of 27.3 W h kg−1. Such a synthetic route to prepare capacitor materials can thoroughly motivate the synergistic effect between electrical double layer capacitors and pseudocapacitors for obtaining high comprehensive performance electrodes in energy storage fields.
Co-reporter:Huanming Zhang, Chunling Zhu, Yujin Chen, Min Yang, Piaoping Yang, Xiaohong Wu, Lihong Qi and Fanna Meng
Journal of Materials Chemistry A 2015 - vol. 3(Issue 4) pp:NaN1426-1426
Publication Date(Web):2014/11/27
DOI:10.1039/C4TA05171H
A facile strategy was developed to fabricate net-like hematite nanoparticle/graphene oxide (GO) composite (NHG), in which the degree of oxidization of GO could be controlled by simply changing annealing time. NHG with GO of appropriate oxidization degree and content exhibited much higher photocatalytic activities than α-Fe2O3 nanorods and commercial α-Fe2O3.
Co-reporter:Fei He, Piaoping Yang, Dong Wang, Na Niu, Shili Gai, Xingbo Li and Milin Zhang
Dalton Transactions 2011 - vol. 40(Issue 41) pp:NaN11030-11030
Publication Date(Web):2011/09/19
DOI:10.1039/C1DT11157D
Well-defined 1D and 3D t-LaVO4:Ln (Ln = Eu3+, Dy3+, Sm3+) nanocrystals with regular and uniform shapes were synthesized through a simple hydrothermal route assisted by disodium ethylenediaminetetraacetic acid (Na2EDTA). X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), as well as kinetic decay curves were employed to characterize the samples. The results show that the reaction time, pH value of the initial solution, and Na2EDTA/La3+ molar ratio all have an important influence on the dimension and shapes of the final products. By introducing the “splitting mechanism” to the dimension and morphology evolution process from one-dimensional (1D) to three-dimensional (3D) t-LaVO4 crystals, the nucleation and crystal growth processes were well demonstrated. The Ln3+ ions doped t-LaVO4 samples exhibit respective bright red, blue-white and orange luminescence of Eu3+, Dy3+, and Sm3+ under ultraviolet excitation, and have potential application in the fields of colour display, UV laser and biomedicine. The results not only expand the knowledge of the properties of lanthanide orthovanadates luminescence, but also contribute to the principles of the crystal growth and dimension transition of this kind of inorganic material.
Co-reporter:Shaohua Huang, Xiao Zhang, Liuzhen Wang, Ling Bai, Jie Xu, Chunxia Li and Piaoping Yang
Dalton Transactions 2012 - vol. 41(Issue 18) pp:NaN5642-5642
Publication Date(Web):2012/02/22
DOI:10.1039/C2DT30221G
Yttrium tungstate precursors with novel 3D hierarchical architectures assembled from nanosheet building blocks were successfully synthesized by a hydrothermal method with the assistance of sodium dodecyl benzenesulfonate (SDBS). After calcination, the precursors were easily converted to Y2(WO4)3 without an obvious change in morphology. The as-prepared precursors and Y2(WO4)3 were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra, respectively. The results reveal that the morphology and dimensions of the as-prepared precursors can be effectively tuned by altering the amounts of organic SDBS and the reaction time, and the possible formation mechanism was also proposed. Upon ultraviolet (UV) excitation, the emission of Y2(WO4)3:x mol% Eu3+ microcrystals can be tuned from white to red, and the doping concentration of Eu3+ has been optimized. Furthermore, the up-conversion (UC) luminescence properties as well as the emission mechanisms of Y2(WO4)3:Yb3+/Ln3+ (Ln = Er, Tm, Ho) microcrystals were systematically investigated, which show green (Er3+, 4S3/2, 2H11/2 → 4I15/2), blue (Tm3+, 1G4 → 3H6) and yellow (Ho3+, 5S2 → 5I8) luminescence under 980 nm NIR excitation. Moreover, the doping concentration of the Yb3+ has been optimized under a fixed concentration of Er3+ for the UC emission of Y2(WO4)3:Yb3+/Er3+.
Co-reporter:Fei He, Na Niu, Lin Wang, Jie Xu, Yan Wang, Guixin Yang, Shili Gai and Piaoping Yang
Dalton Transactions 2013 - vol. 42(Issue 27) pp:NaN10028-10028
Publication Date(Web):2013/04/23
DOI:10.1039/C3DT00029J
In this article, rare earth (RE) ion doped β-NaGdF4 crystals with multicolor up-conversion (UC) emissions and paramagnetic properties were synthesized via a simple one-step precipitation method at room-temperature for the first time. Different surfactants, including Na2EDTA, PVP, SDS, and Na2tar, were introduced to control the crystal size and morphology. It was found that the organic additive can strongly control the size and structure of as-prepared β-NaGdF4:Yb3+,Ln3+ samples through absorbing on the surface of primary particles and/or coordinating with RE3+ ions. Most interestingly, the UC and magnetic properties of the NaGdF4 crystals were also greatly influenced by those additives, which exhibit great distinction. The red emission of 4F9/2 → 4I15/2 (655 nm) in β-NaGdF4:20%Yb3+,2%Er3+, 5F5 → 5I8 (648 nm) in β-NaGdF4:20%Yb3+,2%Ho3+, and NIR emission of 3H4 → 3H6 (797 nm) in β-NaGdF4:20%Yb3+,2%Tm3+ were all markedly enhanced due to abundant organic groups that affect the nonradiative processes. The magnetic properties of β-NaGdF4:Yb3+,Er3+ crystals prepared with different surfactants exhibit typical paramagnetic behavior with different intensities due to the different crystal shape anisotropy.
Co-reporter:Hongbo Fu, Guixin Yang, Shili Gai, Na Niu, Fei He, Jie Xu and Piaoping Yang
Dalton Transactions 2013 - vol. 42(Issue 22) pp:NaN7870-7870
Publication Date(Web):2012/12/04
DOI:10.1039/C2DT32557H
In this paper, well-defined and regular-shaped Na3ScF6 nanocrystals (NCs) have been synthesized in high boiling organic solvents 1-octadecene (ODE) and oleic acid (OA), via the thermal decomposition of rare-earth oleate precursors. It is found that highly uniform monoclinic Na3ScF6 NCs with narrow size distribution have been obtained, which can easily be dispersed in cyclohexane solvent to form transparent colloid solutions. Upon 980 laser diode (LD) excitation, the relative up-conversion (UC) emission intensities of different colors in Yb3+/Er3+, Yb3+/Tm3+ and Yb3+/Ho3+ doped Na3ScF6 can be tuned by altering the Yb3+ doping concentration, resulting in the tunable multicolor in a wide range. On the basis of the emission spectra and the plot of luminescence intensity to pump power, the UC mechanisms of the co-doped Na3ScF6 NCs were investigated in detail. Moreover, the UC emission intensities can be significantly improved by coating a layer of Na3ScF6:Yb3+/Ln3+ shell on Na3ScF6:Yb3+/Ln3+ cores with respect to that of pure Na3ScF6:Yb3+/Ln3+ core NCs. Furthermore, transparent and UC luminescent NCs/polydimethylsiloxane (PDMS) composites with regular dimensions were also fabricated by an in situ polymerization route. Uniform NCs with a wide variation of luminescence colors will show potential applications in diverse fields.
Co-reporter:Zhongyi Niu, Shenghuan Zhang, Yanbo Sun, Shili Gai, Fei He, Yunlu Dai, Lei Li and Piaoping Yang
Dalton Transactions 2014 - vol. 43(Issue 44) pp:NaN16918-16918
Publication Date(Web):2014/09/15
DOI:10.1039/C4DT02385D
The high cost of noble metal nanoparticles used for catalytic reduction of 4-nitrophenol (4-NP) leads to an extensive study of Ni nanoparticles (NPs) for their low cost and magnetic properties. However, the conventional routes for preparing the ferromagnetic Ni NPs usually lead to large particle size and aggregation. In this study, we propose a simple two-step method for the synthesis of hierarchical Ni NP supported silica magnetic hollow microspheres (Ni/SiO2 MHMs). Tiny Ni NPs are well dispersed on the supports with high loading amounts (15 wt%). The size of Ni NPs can be tuned from 10 nm to 21 nm with the size of Ni/SiO2 MHMs increasing from 230 nm to 800 nm. The as-prepared samples exhibit excellent catalytic activity in the reduction of 4-NP. Furthermore, the experimental results prove that the size of Ni NPs plays an important role in the catalytic activity. The catalytic activity of small sized Ni NPs is higher than that of large sized and many other supported Ni NP catalysts as reported. In particular, the magnetic properties of Ni/SiO2 MHMs make them easy to recycle for reuse.
Co-reporter:Ruichan Lv, Chongna Zhong, Arif Gulzar, Shili Gai, Fei He, Rui Gu, Shenghuan Zhang, Guixin Yang and Piaoping Yang
Dalton Transactions 2015 - vol. 44(Issue 42) pp:NaN18595-18595
Publication Date(Web):2015/09/28
DOI:10.1039/C5DT03604F
In this report, MgSiO3:Eu-DOX-DPP-RGD hollow microspheres employed for simultaneous imaging and anti-cancer therapy have been designed by sequentially loading the anti-tumor drugs doxorubicin (DOX), light-activated platinum(IV) pro-drug PPD, and a targeted peptide of NH2-Gly-Arg-Gly-Asp-Ser (RGD) onto MgSiO3:Eu mesoporous hollow spheres, which were synthesized using solid SiO2 spheres as sacrificed template by a facile hydrothermal process based on the Kirkendall effect. The photoluminescence intensity of MgSiO3:Eu has been optimized, which can emit a recognized red signal in vitro and in vivo under modest ultraviolet (UV) irradiation. It was found that the platform has high biocompatibility and could become intracellular through fast and effective endocytosis with the aid of the targeted peptide RGD, and chemotherapeutic drugs DOX and light-activated platinum(IV) pro-drug DPP that can be released from the carrier to induce an obvious inhabitation effect to HeLa cancer cells (survival rate of only 17.4%), which has been verified by in vitro and in vivo results. Moreover, the in vitro result using a photosensitizer ZnPc loaded carrier shows that the system is not suitable for ZnPc induced photodynamic therapy. The apparent imaging effect and high anti-tumor efficacy of this functional system give it great potential in actual clinical applications.
Co-reporter:Huiting Bi, Yunlu Dai, Ruichan Lv, Chongna Zhong, Fei He, Shili Gai, Arif Gulzar, Guixin Yang and Piaoping Yang
Dalton Transactions 2016 - vol. 45(Issue 12) pp:NaN5110-5110
Publication Date(Web):2016/01/29
DOI:10.1039/C5DT04842G
To integrate photothermal therapy (PTT) with chemotherapy for improving anticancer efficiency, we developed a novel and multifunctional doxorubicin (DOX) conjugated copper sulfide nanoparticle (CuS–DOX NP) drug delivery system using hydrazone bonds to conjugate carboxyl-functionalized copper sulfide nanoparticles (CuS NPs) and DOX. On the other hand, the hydrazone bonds could be used for improving the DOX release rate (88.0%) by cleavage in a mildly acidic environment irradiated by 808 nm laser light, which could greatly promote chemo-therapeutic efficacy. Simultaneously, CuS NPs which can absorb near infrared (NIR) light produce a clear thermal effect, giving rise to a synergistic therapeutic effect combined with enhanced chemo-therapy. The DOX-conjugated CuS NPs display an evident in vitro cytotoxicity to HeLa cancer cells under 808 nm light irradiation. High tumor inhibition efficacy has been achieved after 14 day in vivo treatment, performed with intravenous administration of CuS–DOX NPs with 808 nm laser irradiation on H22 tumor-bearing mice. The multifunctional system which was achieved by a facile route should be a potential candidate in the anti-cancer field due to the synergistic therapeutic effect, which is superior to any single approach.
Co-reporter:Xiao Zhang, Piaoping Yang, Chunxia Li, Dong Wang, Jie Xu, Shili Gai and Jun Lin
Chemical Communications 2011 - vol. 47(Issue 44) pp:NaN12145-12145
Publication Date(Web):2011/10/13
DOI:10.1039/C1CC15194K
Well defined, pure hexagonal-phased NaYF4:Yb3+,Er3+/Tm3+ microtubes and microrods were first prepared by a facile and mass production molten salt method without using any surfactant, which offers a new alternative in synthesizing such materials and opens the possibility to meet the increasing commercial demand.
Co-reporter:Yunlu Dai, Huiting Bi, Xiaoran Deng, Chunxia Li, Fei He, Ping'an Ma, Piaoping Yang and Jun Lin
Journal of Materials Chemistry A 2017 - vol. 5(Issue 11) pp:NaN2095-2095
Publication Date(Web):2017/02/21
DOI:10.1039/C7TB00224F
The design of stimuli-responsive drug delivery systems has attracted much attention to improve therapeutic efficacy for clinical applications. Here an 808 nm NIR light responsive dual-drug system was designed for cancer treatment both in vitro and in vivo. Mesoporous silica coated NaYF4:Yb0.4/Tm0.02@NaGdF4:Yb0.1@NaNdF4:Yb0.1 (UCNPs) with a core-shell structure (labeled as UCNPs@mSiO2) was prepared and loaded with the antitumor drug doxorubicin (DOX). The surface of the composite was functionalized with β-cyclodextrin rings bridged by the light cleavable platinum(IV) pro-drug, thus blocking DOX inside the mesopores of silica. When excited by 808 nm NIR light, the emitted UV light from the UCNPs was used to activate the platinum(IV) pro-drug to gain higher toxicity platinum(II) complexes and open the mesopores of silica (at the same time) to release DOX molecules. Both DOX and platinum(II) complexes can kill cancer cells. This dual-drug delivery system may represent a new avenue for the application of UCNPs in photoactivated cancer therapy.
Co-reporter:Dan Yang, Guixin Yang, Jiaqi Li, Shili Gai, Fei He and Piaoping Yang
Journal of Materials Chemistry A 2017 - vol. 5(Issue 22) pp:NaN4161-4161
Publication Date(Web):2017/05/08
DOI:10.1039/C7TB00688H
Two major issues of finding the appropriate photosensitizer and raising the penetration depth of irradiation light exist in further developing of photodynamic therapy (PDT). The excited ultraviolet/visible (UV/vis) irradiation light has a relatively shallow depth of penetration and UV light itself may have sufficient energy to damage normal tissues; these are substantial limitations to successful cancer therapy. Herein, we for the first time report a novel multifunctional nanoplatform for a single 980 nm near-infrared (NIR) light-triggered PDT based on NaGdF4:Yb,Tm@NaGdF4 upconversion nanoparticles (UCNPs) integrated with bismuth oxyhalide (BiOCl) sheets, designated as UCNPs@BiOCl. And UCNPs@BiOCl was fabricated by a convenient, efficient, green, and inexpensive method. Excitingly, layered bismuth oxyhalide materials possess a high photocatalytic performance, unique layered structures and wide light response to a broad wavelength range of ultraviolet to visible light. And the loaded UCNPs can convert NIR light into UV/vis region emissions, which drives the pure water splitting of BiOCl sheets to produce plenty of reactive oxygen species (ROS) to damage tumor cells. The excellent antitumor efficiency of the complex has been evidently attested by comparing experimental results. Our work may make a contribution to the wide application of BiOCl-based materials in biomedicine.
