Co-reporter:Deyan Gong, Ting Cao, Shi-Chong Han, Xiangtao Zhu, Anam Iqbal, Weisheng Liu, Wenwu Qin, Huichen Guo
Sensors and Actuators B: Chemical 2017 Volume 252(Volume 252) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.snb.2017.06.041
•The water soluble copolymer hydrogel poly(NIPAM-co-BODIPY-AA) as nanothermometer has been synthesized.•poly(NIPAM-co-BODIPY-AA) shows properties including good temperature-responsive reversibility and biocompatibility.•The fluorescence intensity increased linearly with increasing physiology temperature (37–42 °C).Herein, A water soluble, visible excited and simple-structured copolymer hydrogel, poly(NIPAM-co-BODIPY-AA), consisting of N-isopropylacrylamide (NIPAM) and derivative of 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) units as thermoresponsive and polarity sensitive fluorescent signalling parts, respectively, has been synthesized. The copolymer exhibits weak fluorescence at temperature low than 35 °C in aqueous solution, whereas the red fluorescence intensity (λem = 605 nm) increases with a 10 folds rise in temperature up to 47 °C with an increase of average lifetime from 0.68 ns up to 2 ns in the thermal transition processes. The fluorescence intensity increased linearly with increasing physiology temperature (37–42 °C). The resultant nanothermometer could feature a high and spontaneous uptaking into the BHK cells. The prepared nanothermometer which is user friendly can provide tools for unveiling intrinsic relationship between the intracellular temperature and could be used in further applications for the fluorescent temperature sensing included parts of physiological temperature range in living cells.poly(NIPAM-co-BODIPY-AA) exhibits fluorescence intensity (λem = 605 nm) increases in temperature from 35 °C up to 47 °C and the fluorescent sensing in living cells.Download high-res image (87KB)Download full-size image
Co-reporter:Xinran Li;Hong Ma;Min Deng;Anam Iqbal;Xiaoyu Liu;Bo Li;Weisheng Liu;Jiping Li
Journal of Materials Chemistry C 2017 vol. 5(Issue 8) pp:2149-2152
Publication Date(Web):2017/02/23
DOI:10.1039/C7TC00305F
A europium functionalized silicon nanoparticle (SiNP) ratiometric fluorescence transducer based on Fluorescence Resonance Energy Transfer (FRET) was designed to detect tetracyline (TC) as an effective antibiotic with high sensitivity and selectivity. SiNPs were prepared by one-step microwave-assisted synthesis from low-cost ethylenediaminetetraacetic acid disodium salt and (3-aminopropyl)triethoxysilane (APTES) as the precursor. The obtained SiNPs served as co-ligands for coordinating with Eu3+ ions, energy donors in FRET, and also a fluorescence reference. The fluorescence intensity ratio of I617/I450 of the transducer displayed a good linear response to TC concentrations in the range of 10 nM to 120 μM with a detection limit of 5.4 nM, and was applied successfully to determine the levels of TC in normal mouse sera and milk samples with high selectivity.
Co-reporter:Min Deng, Deyan Gong, Shi-Chong Han, Xiangtao Zhu, Anam Iqbal, Weisheng Liu, Wenwu Qin, Huichen Guo
Sensors and Actuators B: Chemical 2017 Volume 243() pp:195-202
Publication Date(Web):May 2017
DOI:10.1016/j.snb.2016.11.139
•A novel BODIPY derivative chemodosimeter Bodipy-1 was synthesized.•Bodipy-1 shows excellent selectivity for MeHg+ or Hg2+ over other metal cations.•Confocal microscopy experiments showed that Bodipy-1 can be used in living cells.Herein, a novel chemodosimeter with 1-(2-aminoethyl)-3-phenylthiourea as MeHg+ or Hg2+ reacting group linked via its N atom at position 3 to boron dipyrromethene (Bodipy-1) have been synthesized, which exhibits longer excitation wavelength, selective and sensitive colorimetric and fluorimetric response toward methylmercury (MeHg+) or mercury (Hg2+) in natural media via desulfurization and intramolecular cyclization with a broad pH range from 6–10. It shows low cytotoxicity and excellent membrane permeability towards living cells, which was successfully applied to detect and image intracellular methylmercury or mercury effectively by confocal fluorescence imaging.
Co-reporter:Deyan Gong, Xiangtao Zhu, Yuejun Tian, Shi-Chong Han, Min Deng, Anam Iqbal, Weisheng Liu, Wenwu QinHuichen Guo
Analytical Chemistry 2017 Volume 89(Issue 3) pp:
Publication Date(Web):January 13, 2017
DOI:10.1021/acs.analchem.6b04114
Herein a phenylselenium-substituted BODIPY (1) fluorescent turn-off sensor was developed for the purpose to achieve excellent selectivity and sensitivity for H2S detection based on the substitution reaction of the phenylselenide group at the 3-position with H2S. The excess addition of hydrogen sulfide promoted further substitution of the phenylselenide group at the 5-position of the probe and was accompanied by a further decrease in fluorescence emission intensity. Sensor 1 demonstrated remarkable performance with 49-fold red color fluorescence intensity decrease at longer excitation wavelength, a low detection limit (0.0025 μM), and specific fluorescent response toward H2S over anions, biothiols, and other amino acids in neutral media. It showed no obvious cell toxicity and good membrane permeability, which was well exploited for intracellular H2S detection and imaging through fluorescence microscopy imaging.
Co-reporter:Hong Ma;Xiaoyu Liu;Xudong Wang;Xinran Li;Chengduan Yang
Microchimica Acta 2017 Volume 184( Issue 1) pp:177-185
Publication Date(Web):2017 January
DOI:10.1007/s00604-016-2004-3
We describe a highly sensitive glucose probe based on carbon dots modified with MnO2. A strong reduction of the green fluorescence of the carbon dots (CDs) happened due to the surface energy transfer (SET) from CDs to the deposited MnO2. In the presence of H2O2 (formed via enzymatic oxidation of glucose), fluorescence is restored because the MnO2 nanosheets are reduced to form colorless Mn(II) ions. These findings were used to design a fluorometric glucose assay that has a detection limit as low as 44 nM (at an S/N ratio of 3).
Co-reporter:Yali Guo, Dong Tang, Lilan Zhang, Bo Li, ... Wenwu Qin
Ceramics International 2017 Volume 43, Issue 9(Volume 43, Issue 9) pp:
Publication Date(Web):15 June 2017
DOI:10.1016/j.ceramint.2017.03.033
A facile ultrasonic method has been successfully developed for the fabrication of multifunctional Fe3O4@carbon dot/Ag (Fe3O4@C-dot/Ag) nanocubes (NCs), and the resulting materials are well characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), Vibrating sample magnetometer (VSM) and fluorescence measurements. The Ag nanoparticles (NPs) are uniform and well dispersed on the surface of Fe3O4@C-dot, while maintaining the shape and the size of the core-shell Fe3O4@C-dot NCs. In addition, its catalytic activities are evaluated by measuring the reduction of p-nitroaniline (p-NA) and crystal violet (CV), and the composite materials exhibit excellent catalytic activity towards reduction of p-NA and CV dye, which is superior to most reported catalysts. The good catalytic performance of Fe3O4@C-dot/Ag NCs may be attributed to the specific characteristics of its nanostructure and the synergistic effect on the delivery of electrons between Ag NPs and Fe3O4@C-dot NCs. Furthermore, the as-prepared catalysts also show good activity for the reduction of other nitrobenzene analogs. The effect of solvent and reducing agent was also studied on the catalytic activity of Fe3O4@C-dot/Ag NCs. Most importantly, the Fe3O4@C-dot/Ag catalyst shows excellent recycling stabilities, which can be potentially applied in the fields of catalysis and green chemistry.
Co-reporter:Yali Guo, Jing Qian, Anam Iqbal, Lilan Zhang, ... Wenwu Qin
International Journal of Hydrogen Energy 2017 Volume 42, Issue 22(Volume 42, Issue 22) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.ijhydene.2017.04.253
•A novel cube-like Pd/carbon dots@Fe3O4 hybrid material was successfully prepared.•The hybrid material was employed as a synergistic catalyst for hydrogen generation.•The C-dots can not only immobilize the Pd NPs but also enhance the catalytic rate.•The magnetic properties of hybrid material can achieve effective momentum transfer.In this work, a cube-like Pd/carbon dots@Fe3O4 (Pd/C-dots@Fe3O4) hybrid material has been successfully prepared through a facile ultrasonic assisted chemical reduction method, and used as a highly efficient catalyst for the hydrolytic dehydrogenation of NaBH4 in alkaline media. It is found that the small Pd nanoparticles (NPs) are uniform and well dispersed on the surface of C-dots@Fe3O4 nanocubes (NCs). Benefiting from the advantages of the unique cube-like structure, the super conductivity of carbon dots (C-dots) and the synergistic effect between Pd NPs and C-dots@Fe3O4 support, Pd/C-dots@Fe3O4 NCs exhibits the highest catalytic performance among all the as-prepared samples. The possible reaction mechanism is discussed. Furthermore, the effects of reaction temperature, NaBH4 concentration and NaOH concentration on the catalytic activity of Pd/C-dots@Fe3O4 NCs are studied. Besides, the magnetic properties of Pd/C-dots@Fe3O4 NCs can achieve effective momentum transfer with the assistance of the external magnetic field, and a higher catalytic activity is observed for Pd/C-dots@Fe3O4 NCs in self-stirring mode than in magnetic-stirring mode. This novel catalyst also exhibits good stability and can be easily separated by a magnet, showing great potential for renewable energy applications.Download high-res image (229KB)Download full-size image
Co-reporter:Lilan Zhang;Yali Guo;Anam Iqbal;Bo Li;Min Deng
Journal of Nanoparticle Research 2017 Volume 19( Issue 4) pp:
Publication Date(Web):2017 April
DOI:10.1007/s11051-017-3829-3
Herein, six kinds of PdNPs (including icosahedron, sphere, spindle, cube, rod, and wire) were synthesized via simple methods. The catalytic activities were investigated by the reduction reaction of Cr(VI) and Suzuki coupling reaction. Chemically synthesized morphologies of the six catalysis were characterized by transmission electron microscopy, field emission scanning electron microscopy, and X-ray diffraction, etc. Pd icosahedron shows a better catalytic property than other PdNPs with a rate constants 0.42 min−1 for the reduction of Cr(VI). Moreover, the electrocatalyst shows that Pd icosahedron possesses a bigger surface area of 8.56 m2/g than other nanoparticles, which is attributed to the better catalyst. The Pd icosahedron possesses a better catalytic property, attributing to the abundant exposed {111} facets with high activity on Pd icosahedron. The catalytic activities are closely related to the surface area with the following order: icosahedrons ≥ sphere > rod > spindle > cube > wire. The Pd icosahedron catalyst represents a strong activity for Suzuki coupling reaction as well, outweighting is 80%. The results reveal that Pd icosahedron acts as an efficient catalyst compared to other PdNPs (wire, rod, sphere, spindle, and cube).
Co-reporter:Yali Guo, Lilan Zhang, Xiaoyu Liu, Bo Li, Dong Tang, Weisheng Liu and Wenwu Qin
Journal of Materials Chemistry A 2016 vol. 4(Issue 11) pp:4044-4055
Publication Date(Web):12 Feb 2016
DOI:10.1039/C5TA10708C
In this work, magnetic core–shell carbon dot@MFe2O4 (C-dot@MFe2O4) (M = Mn, Zn and Cu) hybrid materials are successfully prepared through a facile ultrasonic method. The resulting nanomaterials are well characterized using various techniques. It is indicated that the MFe2O4 microspheres are homogeneously dispersed and coated with low contrast continuous C-dot layers to form a core–shell structure. In addition, their catalytic activities are evaluated by measuring the reduction of p-nitrophenol (p-NP). The catalytic activity is found to strongly depend on the composition and morphology of the catalyst, and follows an order of C-dot@CuFe2O4 > CuFe2O4 > C-dot@MnFe2O4 > C-dot@ZnFe2O4 > MnFe2O4 > ZnFe2O4 > C-dots. C-dot@CuFe2O4 shows excellent activity with a rate constant of 8.05 × 104 min−1 g−1 which is superior to most reported catalysts. The good catalytic performance of C-dot@CuFe2O4 may be attributed to the specific characteristics of its nanostructure and the synergistic effect between CuFe2O4 and the C-dots. The effects of the substituent and reducing agent are investigated. Furthermore, the catalyst can be easily recovered using a magnetic field and shows good stability; it can be reused for five successive experiments with a conversion efficiency of more than 95%. This novel catalyst also exhibits excellent catalytic performance for the degradation of other organic dyes, such as methylene blue (MB) and rhodamine B (RhB), and can be used for the purification of contaminated water. These results indicate that C-dot@CuFe2O4 is an efficient catalyst for environmental wastewater treatment.
Co-reporter:Bo Li, Xudong Wang, Yali Guo, Anam Iqbal, Yaping Dong, Wu Li, Weisheng Liu, Wenwu Qin, Shizhen Chen, Xin Zhou and Yunhuang Yang
Dalton Transactions 2016 vol. 45(Issue 13) pp:5484-5491
Publication Date(Web):04 Jan 2016
DOI:10.1039/C5DT04488J
A one-step hydrothermal method was developed to fabricate Fe3O4–carbon dots (Fe3O4–CDs) magnetic–fluorescent hybrid nanoparticles (NPs). Ferric ammonium citrate (FAC) was used as a cheap and nontoxic iron precursor and as the carbon source. Moreover, triethylenetetramine (TETA) was used to improve the adhesive strength of CDs on Fe3O4 and the fluorescence intensity of CDs. The prepared water-soluble hybrid NPs not only exhibit excellent superparamagnetic properties (Ms = 56.8 emu g−1), but also demonstrate excitation-independent photoluminescence for down-conversion and up-conversion at 445 nm. Moreover, the prepared water-soluble Fe3O4–CDs hybrid NPs have a dual modal imaging ability for both magnetic resonance imaging (MRI) and fluorescence imaging.
Co-reporter:Min Deng, Chengduan Yang, Deyan Gong, Anam Iqbal, Xiaoliang Tang, Weisheng Liu, Wenwu Qin
Sensors and Actuators B: Chemical 2016 Volume 232() pp:492-498
Publication Date(Web):September 2016
DOI:10.1016/j.snb.2016.04.003
•Two BODIPY derivative dyes 1 and 2 were synthesized and their crystal structures were obtained.•Dyes 1 and 2 were with pKa values near-neutral (around 6.5 and 6.8).•Confocal microscopy experiments showed that 1 and 2 can be used in living cells.Two new 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) dyes (1 and 2) with piperazine subunits on position 3 or 5 were synthesized. Their absorption and steady-state fluorescence properties were investigated as a function of solvent. In water/MeCN (9:1, V/V) solution, the dyes show fluorescent enhancement upon increasing the acidity of the solution. They can be used in water/MeCN (9:1, V/V) solution as fluorescent pH probes excitable with visible light, with pKa values near-neutral (around 6.5 and 6.8). Dyes 1 and 2 are readily taken up by biological cells in the cytosol where it has no obvious toxic effects.
Co-reporter:Chengduan Yang, Deyan Gong, Xudong Wang, Anam Iqbal, Min Deng, Yali Guo, Xiaoliang Tang, Weisheng Liu, Wenwu Qin
Sensors and Actuators B: Chemical 2016 Volume 224() pp:110-117
Publication Date(Web):1 March 2016
DOI:10.1016/j.snb.2015.10.037
•A BODIPY derivative sensor 1 was synthesized and its crystal structure was obtained.•Sensor 1 shows 90 nm bathochromic shifts and a large increase in the fluorescence intensity upon binding copper in HEPES buffer solution.•Confocal microscopy experiments showed that 1 can be used for detection of Cu2+ levels within living cells.A highly selective fluorescent indicator for copper, substituted with a 1-(furan-2-yl)-N-((pyridin-2-yl) methyl)methanamine (FPA) group at the position 3 or 5 of the BODIPY has been synthesized. The BODIPY indicator forms 1:1 complexes with Cu2+ ions producing large bathochromic shifts in the absorption (from 480 nm to 570 nm) and fluorescence spectra (from 550 nm to 600 nm) with a change of solution color and cation-induced fluorescence amplifications. The new boradiazaindacene dye exhibited a high affinity and selectivity for Cu2+ over competing metal ions. Confocal microscopy experiments showed that bodipy-FPA can be used for detection of Cu2+ levels within living cells.
Co-reporter:Anam Iqbal, Yuejun Tian, Xudong Wang, Deyan Gong, Yali Guo, Kanwal Iqbal, Zhiping Wang, Weisheng Liu, Wenwu Qin
Sensors and Actuators B: Chemical 2016 Volume 237() pp:408-415
Publication Date(Web):December 2016
DOI:10.1016/j.snb.2016.06.126
•CDs (CA + Phen) was successfully prepared by the one step solid state method.•Fe2+ and Fe3+ can effectively quench the fluorescence of CDs (CA + Phen).•CDs (CA + Phen) shows remarkable properties including very fast and simple, one step, cost-effective as well as environmental-friendly.•CDs (CA + Phen) can be use for detecting Fe in cell and milk.A new kind of convenient, low-cost, environmentally friendly, and simple one step synthetic route for the preparation of C-dots-based CDs (CA + Phen) fluorescent turn-off probe for Fe2+ and Fe3+ from 1,10-phenanthroline (Phen) using anhydrous citric acid (CA) as the sole precursor without any solvents by solid state method. Only the Fe2+ and Fe3+ can readily quench the fluorescence of the CDs (CA + Phen), indicating a remarkably high selectivity towards Fe2+ and Fe3+ over other metals with a detection limit as low as 20 nM and 35 nM. The CDs (CA + Phen) exhibited a low cytotoxicity and could label the HK-2 cells. Additionally, this CDs (CA + Phen) has been successfully applied for the determination of Fe in real sample of milk. Endowed with relatively high sensitivity and selectivity, the present sensor holds the potential to be applied for the detection of Fe2+ and Fe3+ in aqueous media.The CDs (CA + Phen) could be potentially utilized as an excellent optical sensor for the quantitative analysis of Fe2+ or Fe3+ in living cells.
Co-reporter:Xudong Wang, Dan Wang, Yali Guo, Chengduan Yang, Xiaoyu Liu, Anam Iqbal, Weisheng Liu, Wenwu Qin, Dan Yan, Huichen Guo
Biosensors and Bioelectronics 2016 Volume 77() pp:299-305
Publication Date(Web):15 March 2016
DOI:10.1016/j.bios.2015.09.044
•MnO2-phenol formaldehyde resin (MnO2-PFR) nanocomposite is successfully prepared by a simple chemical reduction process.•In the presence of glutathione (GSH), the fluorescence of PFR could be recovered due to MnO2 was reduced to Mn2+ by GSH.•MnO2-PFR nanocomposite shows remarkable properties including very fast and simple, onestep, cost-effective as well as environmental-friendly.•The nanocomposite can be use for detecting glutathione in blood serum.MnO2-phenol formaldehyde resin (MnO2-PFR) nanocomposite is successfully prepared by a simple chemical reduction process. The resultant MnO2-PFR nanocomposite is well characterized. The absorption band of non-fluorescent MnO2 nanosheets overlaps well with the fluorescence emission of PFR nanoparticles. The green fluorescence of PFR in this nanocomposite can be effectively quenched by fluorescence resonance energy transfer from PFR to MnO2. In the presence of glutathione (GSH), the fluorescence of PFR could be recovered due to MnO2 was reduced to Mn2+ by GSH. The nanocomposite can be use for detecting glutathione in blood serum.
Co-reporter:Deyan Gong, Yuejun Tian, Chengduan Yang, Anam Iqbal, Zhiping Wang, Weisheng Liu, Wenwu Qin, Xiangtao Zhu, Huichen Guo
Biosensors and Bioelectronics 2016 Volume 85() pp:178-183
Publication Date(Web):15 November 2016
DOI:10.1016/j.bios.2016.05.013
•The discrimination of cysteine from homocysteine and glutathione was achieved through BODIPY-GH.•BODIPY-GH shows simple, low cytotoxicity, good biocompatibility and can be use for detecting and imaging cysteine in cells.•The detection limit was calculated to be 54.6 nM (0–50 μM).Herein, a fluorescent probe BODIPY-based glyoxal hydrazone (BODIPY-GH) (1) for cysteine based on inhibiting of intramolecular charge transfer (ICT) quenching process upon reaction with the unsaturated aldehyde has been synthesized, which exhibits longer excitation wavelength, selective and sensitive colorimetric and fluorimetric response toward cysteine in natural media. The probe shows highly selectivity towards cysteine over homocysteine and glutathione as well as other amino acids with a significant fluorescence enhancement response within 15 min In the presence of 50 equiv. of homocysteine, the emission increased slightly within 15 min and completed in 2.5 h to reach its maximum intensity. Therefore, the discrimination of cysteine from homocysteine and glutathione can be achieved through detection of probe 1. It shows low cytotoxicity and excellent membrane permeability toward living cells, which was successfully applied to detect and image intracellular cysteine effectively by confocal fluorescence imaging.
Co-reporter:Xiaoyu Liu, Yali Guo, Dan Wang, Xiaolong Yang, Weisheng Liu, Wenwu Qin
Dyes and Pigments 2015 Volume 113() pp:327-335
Publication Date(Web):February 2015
DOI:10.1016/j.dyepig.2014.08.024
•Nanosheet fluorescent chemosensor based on graphite oxide covalently functionalized with coumarin has been prepared.•Nanosheet fluorescent probe can offer good dispersion in aqueous solution and optical properties.•Nanosheet fluorescent probe was sensitive response of pH value.•Nanosheet fluorescent probe can be transfected into the living cells and applied for fluorescence imaging.A new nanosheet fluorescent chemosensor (GO–NH–COUR) based on graphite oxide (GO) covalently functionalized with a 4-methyl-7-aminocoumarin (NH2-COUR) has been prepared. The GO were prepared by a modified Hummers method. The products were characterized by TEM, XRD, and FT-IR. The photophysical properties of GO, NH2–COUR and GO–NH–COUR in aqueous and ethanol solution have been investigated by UV/vis spectrophotometry, steady-state and time-resolved fluorometry. They reflect a large effect of the NH2–COUR substituent on the fluorescence characteristics of GO. In aqueous solution, GO–NH–COUR probes undergo protonation–deprotonation in the acid to basic pH range, producing intensity increases with acid to near-neutral pH range. The advantages of the newly prepared nanoparticles are that they offer good dispersion in aqueous solution and optical properties. Confocal microscopy experiments showed that GO–NH–COUR can be transfected into the living cells and applied for fluorescence imaging.
Co-reporter:Xudong Wang, Dan Wang, Yali Guo, Chengduan Yang, Anam Iqbal, Weisheng Liu, Wenwu Qin, Dan Yan and Huichen Guo
Dalton Transactions 2015 vol. 44(Issue 12) pp:5547-5554
Publication Date(Web):09 Feb 2015
DOI:10.1039/C5DT00128E
A highly sensitive carbon dot–imidazole (CD–imidazole) nanoprobe is prepared through covalently conjugating imidazole group onto the surface of carbon dots for water fluorescence. In organic solvents, quenching of fluorescence occurs via photoinduced electron transfer (PET) process from the imidazole nitrogen to the CD acceptor. Addition of a trace amount of water into CD nanocomposites in various organic solvents leads to a fluorescence turn-on response, which can be attributed to the suppression of PET due to the formation of the “free” ion pair by proton transfer from the carboxyl groups that are on the CDs surface to the imidazole nitrogen through a water-bridge. This phenomenon can be used for the highly selective detection of trace amounts of water in organic solvents. Laser confocal microscope experiment shows the potential utilization of CD–imidazole for the probed proton-transfer reactions in living cells.
Co-reporter:Yali Guo, Xiaoyu Liu, Xudong Wang, Anam Iqbal, Chengduan Yang, Weisheng Liu and Wenwu Qin
RSC Advances 2015 vol. 5(Issue 116) pp:95495-95503
Publication Date(Web):23 Oct 2015
DOI:10.1039/C5RA18087B
A novel carbon dot/NiAl-layered double hydroxide (C-dot/NiAl–LDH) hybrid material is successfully prepared through electrostatic self-assembly of positively charged NiAl–LDH nanoplates (3.74 ± 0.3 mV) and negatively charged C-dots (−5.09 ± 0.5 mV). The morphology, structure, composition and fluorescence properties of the hybrid material are characterized by different techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and fluorescence spectroscopy. Moreover, C-dot/NiAl–LDH exhibits intrinsic peroxidase-like activity, which shows enhanced catalytic activities compared with C-dots and NiAl–LDH. The hybrid material facilitates the electron transfer between 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2, which oxidizes TMB to form a blue product. On the basis of the peroxidase-like activity of C-dot/NiAl–LDH, the hybrid material can employ colorimetric detection of H2O2 with a lower detection limit of 0.11 μM. The hybrid material also shows better stability than horseradish peroxidase (HRP) when exposed to solutions with different organic solvents and temperatures. The proposed method is successfully applied for the determination of H2O2 in milk samples.
Co-reporter:Yali Guo;Xiaoyu Liu;Chengduan Yang;Xudong Wang;Dan Wang;Anam Iqbal; Weisheng Liu ; Wenwu Qin
ChemCatChem 2015 Volume 7( Issue 16) pp:2467-2474
Publication Date(Web):
DOI:10.1002/cctc.201500263
Abstract
A cobalt@carbon-dots (Co@C-dots) hybrid material is successfully prepared and well characterized. The hybrid material exhibits intrinsic peroxidase-like activity and can be utilized for the degradation of methylene blue; it shows enhanced catalytic activities compared with bare Co nanoparticles or C-dots. The good catalytic performance of the hybrid material may be attributed to synergistic effects between the Co nanoparticles and C-dots. Furthermore, the catalytic mechanism of the Co@C-dots hybrid material is also studied by using steady-state and time-resolved fluorometric analysis, which reveals that Co@C-dots can effectively decompose H2O2 to produce reactive hydroxyl radicals (.OH). These results suggest that the Co@C-dots hybrid material could be a promising material applied for biochemical analysis and water treatment.
Co-reporter:Yali Guo;Xiaoyu Liu;Chengduan Yang;Xudong Wang;Dan Wang;Anam Iqbal; Weisheng Liu ; Wenwu Qin
ChemCatChem 2015 Volume 7( Issue 16) pp:
Publication Date(Web):
DOI:10.1002/cctc.201500849
Co-reporter:Yali Guo, Dan Wang, Xiaoyu Liu, Xudong Wang, Weisheng Liu and Wenwu Qin
New Journal of Chemistry 2014 vol. 38(Issue 12) pp:5861-5867
Publication Date(Web):16 Sep 2014
DOI:10.1039/C4NJ01087F
The nickel@carbon dots hybrid material (Ni@C-dots) was prepared through a simple reduction route and characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and fluorescence spectroscopy. Additionally, the hybrid material was tested as a catalyst to reduce toxic Cr(VI) to nontoxic Cr(III), and UV-vis spectrophotometry was employed to monitor the reduction process. According to the results, the Ni@C-dots hybrid material showed excellent hydrophilicity, good stability, and highly catalytic activity at room temperature.
Co-reporter:Xiaoting Yu, Xu Jia, Xiaolong Yang, Weisheng Liu and Wenwu Qin
RSC Advances 2014 vol. 4(Issue 45) pp:23571-23579
Publication Date(Web):08 May 2014
DOI:10.1039/C4RA03183K
A highly selective copper(II) sensor based on BODIPY-functionalized silica nanoparticles, BODIPY–DPA@SN, is designed and synthesized. Its absorption and fluorescence maxima in dry organic solvents are red-shifted by ∼75 and ∼50 nm compared with those of the BODIPY fluorophore and are blue-shifted by ∼55 and ∼15 nm, respectively, in aqueous–organic (1:1, v/v) media with fluorescence enhancement. The fluorescence intensity almost increases linearly as a function of water concentration (below 5%, v/v). BODIPY–DPA@SN exhibits high specificity for Cu2+ over other transition metal ions in aqueous–organic media, resulting in notable fluorescence quenching and a visible pink-to-yellow color change. Confocal microscopy experiments successfully proved that BODIPY–DPA@SN can be a biosensor for copper in living cells.
Co-reporter:Dan Wang, Yali Guo, Weisheng Liu and Wenwu Qin
RSC Advances 2014 vol. 4(Issue 15) pp:7435-7439
Publication Date(Web):25 Nov 2013
DOI:10.1039/C3RA45310C
Fluorescent Ni@SiO2–CDs magnetic nanocomposite powder was prepared and its photoluminescence properties characterized. The photoluminescence properties are quite different in solid state and in ethanol solution.
Co-reporter:Dan Wang, Xudong Wang, Yali Guo, Weisheng Liu and Wenwu Qin
RSC Advances 2014 vol. 4(Issue 93) pp:51658-51665
Publication Date(Web):06 Oct 2014
DOI:10.1039/C4RA11158C
Carbon dots (CDs) and their L-cysteine (S doped CDs) and urea (N doped CDs) doped analogues were made by using the simple and low cost carbon source – pure milk. Milk-CDs have an average diameter of about 5 ± 0.27 nm, whereas S doped CDs and N doped CDs have an average diameter of about 4 ± 0.07 nm and 3 ± 0.07 nm, respectively. The effects of the L-cysteine and urea doping on the spectroscopic and photophysical properties compared with Milk-CDs were studied by means of UV/vis absorption, steady-state, and time-resolved fluorometry. The maxima fluorescence excitation of S doped CDs and N doped CDs are blue-shifted by 40 and 60 nm and fluorescence emission maxima are blue shifted by 36 and 30 nm, respectively compared with those of the Milk-CDs. Furthermore, the excitation maxima of the up-conversion fluorescence emission (anti-Stokes) of N doped CDs are blue-shifted by 90 nm and emission maxima are blue shifted by 50 nm compared with those of the Milk-CDs and S doped CDs, respectively. N doped CDs have the highest fluorescence quantum yield among the three CDs. Moreover, the confocal microscopy experiments showed that the Milk-CDs, S doped CDs and N doped CDs can be used within living cells.
Co-reporter:Xu Jia, Xiaoting Yu, Xiaolong Yang, Jie Cui, Xiaoliang Tang, Weisheng Liu, Wenwu Qin
Dyes and Pigments 2013 Volume 98(Issue 2) pp:195-200
Publication Date(Web):August 2013
DOI:10.1016/j.dyepig.2013.02.013
A highly selective fluorescent indicator for copper, substituted with an aminoquinoline group at the position 3 or 5 of the BODIPY has been synthesized. The indicator has very low fluorescence quantum yield in acetonitrile with emission maxima at 580 nm. Upon binding copper it shows 50 nm bathochromic shifts with a change of solution color and a large increase in the fluorescence intensity. The fluorescence lifetime in acetonitrile was too short and could not be determined; whereas fluorescence decay profile of the copper complex was described by a mono-exponential decay with the lifetime of 4.38 ns. ESI-MS enabled detection of a Cu·1 CN complexes which was fromed by C–C bond cleavage of acetonitrile.Highlights► An aminoquinoline substituted BODIPY dye 1 was synthesis and got its crystal structure. ► 1 shows bathochromic shifts with a large increase in the fluorescence intensity upon binding copper. ► Cu·1 adduct suggest the presence of CN complexes which is from C–C bond cleavage of acetonitrile. ► Fluorescence lifetime of 1 in acetonitrile could not be determined while Cu·1 was described by a mono-exponential decay.
Co-reporter:Xiaoyan Xiang, Dan Wang, Yali Guo, Weisheng Liu and Wenwu Qin
Photochemical & Photobiological Sciences 2013 vol. 12(Issue 7) pp:1232-1241
Publication Date(Web):08 Apr 2013
DOI:10.1039/C3PP00007A
A naphthalene-based bichromophoric fluorescent sensor 2,2′-[oxy-bis(2-oxatetramethyleneoxy)]-bis[N-(2-naphthyl)-benzamide)] (1) was synthesized and characterized. Fluorescence decay for 1 in alcoholic solvents in the region of 415–460 nm revealed bi-exponential behavior. The faster component of the decay can be attributed to the formation of dimers. Above 480 nm, besides the dimer, there is also a little excimer formation and this excimer emits at longer wavelengths than the dimer. The observation of the change of the fluorescence emission spectra upon addition of water in EtOH–water mixtures is in line with the formation of water-bridged complexes preventing excimer formation. The sensor shows an increase in fluorescence intensity upon increasing Mg2+ or Ca2+ concentration in EtOH because the formation of the excimer can be hindered upon complexation with Mg2+ or Ca2+ ions. Because of the competition between hydrated metal ions and the water-bridged complex, spectral changes by complexation with Mg2+ or Ca2+ in EtOH–H2O (9:1 v/v) are quite different from those in neat ethanol. The ground-state dissociation constant Kd estimated for the complex with Mg2+ or Ca2+ was found to be around 2.0 mM in EtOH–H2O (9:1 v/v), which makes it suitable for the measurement of the concentrations of these ions in physiologically relevant concentration ranges.
Co-reporter:Chan Xu, Weisheng Liu, and Wenwu Qin
The Journal of Physical Chemistry A 2011 Volume 115(Issue 17) pp:4288-4298
Publication Date(Web):April 11, 2011
DOI:10.1021/jp200514u
A new symmetric polioxo ethylene chain fluorescent probe containing 2-aminoanthracene bichromophoric as the terminal group for the alkaline earth metal cation, 2,2′-[oxybis(3-oxapentamethyleneoxy)]-bis[N-(2-anthryl)benzamide)] (1), has been synthesized. The photophysical properties of 1 have been studied by means of absorption, fluorescence spectroscopy, and 1H NMR. The difference in emission spectra response to concentration of model compound 2-acetamido-anthracene and 1 in acetonitrile implies that intermolecular excited dimers is likely to occur. Fluorescence decay profiles of 2-acetamido-anthracene can be described by a biexponential fit, while three lifetimes, two of which are similar as those of 2-acetamido-anthracene, are found for 1. The third lifetime might be attributed to intramolecular excited dimers. Complex formation with alkaline earth metal ions are investigated in acetonitrile as solvent via fluorimetric titrations. Fluorescence intensity trend of the complex with Mg2+ differed from those of other alkaline earth metal ions. The compound forms 1:2 (ligand/Mg2+) complex with Mg2+ while formed 1:1 complexes with Ca2+, Sr2+, and Ba2+, producing large hypochromic shifts in the emission spectra and significant cation-induced fluorescence amplifications. On the contrary, the addition of Ca2+, Sr2+, or Ba2+ lead to a decrease in the fluorescence emission first, then an increase and blue shift in emission could be found at the end.
Co-reporter:Volker Leen Dr. Dr.;Wensheng Yang;Jie Cui;Chan Xu;Xiaoliang Tang Dr.;Weisheng Liu Dr.;Koen Robeyns Dr.;Luc VanMeervelt ;David Beljonne Dr.;Roberto Lazzaroni Dr.;Claire Tonnelé;Noël Boens ;Wim Dehaen
Chemistry – An Asian Journal 2010 Volume 5( Issue 9) pp:2016-2026
Publication Date(Web):
DOI:10.1002/asia.201000248
Abstract
Starting from the conformationally unconstrained compound 3,5-di-(2-bromophenoxy)-4,4-difluoro-8-(4-methylphenyl)-4-bora-3a,4a-diaza-s-indacene (1), two BODIPY dyes (2 and 3) with increasingly rigid conformations were synthesized in outstanding total yields through palladium catalyzed intramolecular benzofuran formation. Restricted bond rotation of the phenoxy fragments leads to dyes 2 and 3, which absorb and fluoresce more intensely at longer wavelengths relative to the unconstrained dye 1. Reduction of the conformational flexibility in 2 and 3 leads to significantly higher fluorescence quantum yields compared to those of 1. X-ray diffraction analysis shows the progressively more extended planarity of the chromophore in line with the increasing conformational restriction in the series 123, which explains the larger red shifts of the absorption and emission spectra. These conclusions are confirmed by quantum chemical calculations of the lowest electronic excitations in 1, 1a, 2, 2a, 3 and dyes of related chemical structures. The effect of the molecular structure on the visible absorption and fluorescence emission properties of 1, 1a, 2, 2a, 3 has been examined as a function of solvent by means of the new, generalized treatment of the solvent effect (J. Phys. Chem. B 2009, 113, 5951–5960). Solvent polarizability is the primary factor responsible for the small solvent-dependent shifts of the visible absorption and fluorescence emission bands of these dyes.
Co-reporter:Volker Leen Dr. Dr.;Wensheng Yang;Jie Cui;Chan Xu;Xiaoliang Tang Dr.;Weisheng Liu Dr.;Koen Robeyns Dr.;Luc VanMeervelt ;David Beljonne Dr.;Roberto Lazzaroni Dr.;Claire Tonnelé;Noël Boens ;Wim Dehaen
Chemistry – An Asian Journal 2010 Volume 5( Issue 9) pp:
Publication Date(Web):
DOI:10.1002/asia.201090028
Co-reporter:Bo Li, Xudong Wang, Yali Guo, Anam Iqbal, Yaping Dong, Wu Li, Weisheng Liu, Wenwu Qin, Shizhen Chen, Xin Zhou and Yunhuang Yang
Dalton Transactions 2016 - vol. 45(Issue 13) pp:NaN5491-5491
Publication Date(Web):2016/01/04
DOI:10.1039/C5DT04488J
A one-step hydrothermal method was developed to fabricate Fe3O4–carbon dots (Fe3O4–CDs) magnetic–fluorescent hybrid nanoparticles (NPs). Ferric ammonium citrate (FAC) was used as a cheap and nontoxic iron precursor and as the carbon source. Moreover, triethylenetetramine (TETA) was used to improve the adhesive strength of CDs on Fe3O4 and the fluorescence intensity of CDs. The prepared water-soluble hybrid NPs not only exhibit excellent superparamagnetic properties (Ms = 56.8 emu g−1), but also demonstrate excitation-independent photoluminescence for down-conversion and up-conversion at 445 nm. Moreover, the prepared water-soluble Fe3O4–CDs hybrid NPs have a dual modal imaging ability for both magnetic resonance imaging (MRI) and fluorescence imaging.
Co-reporter:Xinran Li, Hong Ma, Min Deng, Anam Iqbal, Xiaoyu Liu, Bo Li, Weisheng Liu, Jiping Li and Wenwu Qin
Journal of Materials Chemistry A 2017 - vol. 5(Issue 8) pp:NaN2152-2152
Publication Date(Web):2017/01/31
DOI:10.1039/C7TC00305F
A europium functionalized silicon nanoparticle (SiNP) ratiometric fluorescence transducer based on Fluorescence Resonance Energy Transfer (FRET) was designed to detect tetracyline (TC) as an effective antibiotic with high sensitivity and selectivity. SiNPs were prepared by one-step microwave-assisted synthesis from low-cost ethylenediaminetetraacetic acid disodium salt and (3-aminopropyl)triethoxysilane (APTES) as the precursor. The obtained SiNPs served as co-ligands for coordinating with Eu3+ ions, energy donors in FRET, and also a fluorescence reference. The fluorescence intensity ratio of I617/I450 of the transducer displayed a good linear response to TC concentrations in the range of 10 nM to 120 μM with a detection limit of 5.4 nM, and was applied successfully to determine the levels of TC in normal mouse sera and milk samples with high selectivity.
Co-reporter:Yali Guo, Lilan Zhang, Xiaoyu Liu, Bo Li, Dong Tang, Weisheng Liu and Wenwu Qin
Journal of Materials Chemistry A 2016 - vol. 4(Issue 11) pp:NaN4055-4055
Publication Date(Web):2016/02/12
DOI:10.1039/C5TA10708C
In this work, magnetic core–shell carbon dot@MFe2O4 (C-dot@MFe2O4) (M = Mn, Zn and Cu) hybrid materials are successfully prepared through a facile ultrasonic method. The resulting nanomaterials are well characterized using various techniques. It is indicated that the MFe2O4 microspheres are homogeneously dispersed and coated with low contrast continuous C-dot layers to form a core–shell structure. In addition, their catalytic activities are evaluated by measuring the reduction of p-nitrophenol (p-NP). The catalytic activity is found to strongly depend on the composition and morphology of the catalyst, and follows an order of C-dot@CuFe2O4 > CuFe2O4 > C-dot@MnFe2O4 > C-dot@ZnFe2O4 > MnFe2O4 > ZnFe2O4 > C-dots. C-dot@CuFe2O4 shows excellent activity with a rate constant of 8.05 × 104 min−1 g−1 which is superior to most reported catalysts. The good catalytic performance of C-dot@CuFe2O4 may be attributed to the specific characteristics of its nanostructure and the synergistic effect between CuFe2O4 and the C-dots. The effects of the substituent and reducing agent are investigated. Furthermore, the catalyst can be easily recovered using a magnetic field and shows good stability; it can be reused for five successive experiments with a conversion efficiency of more than 95%. This novel catalyst also exhibits excellent catalytic performance for the degradation of other organic dyes, such as methylene blue (MB) and rhodamine B (RhB), and can be used for the purification of contaminated water. These results indicate that C-dot@CuFe2O4 is an efficient catalyst for environmental wastewater treatment.
Co-reporter:Xudong Wang, Dan Wang, Yali Guo, Chengduan Yang, Anam Iqbal, Weisheng Liu, Wenwu Qin, Dan Yan and Huichen Guo
Dalton Transactions 2015 - vol. 44(Issue 12) pp:NaN5554-5554
Publication Date(Web):2015/02/09
DOI:10.1039/C5DT00128E
A highly sensitive carbon dot–imidazole (CD–imidazole) nanoprobe is prepared through covalently conjugating imidazole group onto the surface of carbon dots for water fluorescence. In organic solvents, quenching of fluorescence occurs via photoinduced electron transfer (PET) process from the imidazole nitrogen to the CD acceptor. Addition of a trace amount of water into CD nanocomposites in various organic solvents leads to a fluorescence turn-on response, which can be attributed to the suppression of PET due to the formation of the “free” ion pair by proton transfer from the carboxyl groups that are on the CDs surface to the imidazole nitrogen through a water-bridge. This phenomenon can be used for the highly selective detection of trace amounts of water in organic solvents. Laser confocal microscope experiment shows the potential utilization of CD–imidazole for the probed proton-transfer reactions in living cells.
