Co-reporter:Yuan Chen, Yawen Wang, Jian Peng, Qingchi Xu, Jian Weng, and Jun Xu
ACS Nano March 28, 2017 Volume 11(Issue 3) pp:2756-2756
Publication Date(Web):March 6, 2017
DOI:10.1021/acsnano.6b07777
Ultrathin nanowires (NWs) are considered to be ideal building blocks for the assembly of complex nanostructures toward future nanodevices. The polymer/particle duality of ultrathin NWs plays an important role in the study of solution phase self-assembly behavior of ultrathin NWs; yet it has not been fully exploited. Herein, we demonstrate the effects of the polymer/particle duality of ultrathin NWs on the morphologies of assembled complex nanostructures. The length of ultrathin AuNWs directly correlates with the flexibility of NWs and affects the polymer-like assembly of NWs, while the concentration of surfactants determines interfacial tension and ligand–solvent interactions and affects both polymer-like and colloidal assembly of NWs. By fine-tuning these two factors, ultrathin AuNWs can swing between “soft” and “hard” building blocks, and highly uniform nanorings, nanograins, nanobundles, and superlattice-like nanospheres are obtained. The different assembly behavior of long and short NWs can be considered as two components to construct anisotropic complex nanostructures, in analogy with the fabrication of polymer–inorganic nanoparticle hybrid nanostructures. We synthesized anisotropic structures of Au nanodiamond rings and nanonecklaces by the coassembly of polymer-like long NWs with particle-like short NWs or Au nanoparticles. This strategy could potentially be extended to the organization of anisotropic complex nanostructures with other ultrathin NW systems in the future.Keywords: anisotropic nanostructures; emulsion; polymer-like assembly; self-assembly; ultrathin gold nanowires;
Co-reporter:Ying He, Yuan Chen, Qingchi Xu, Jun XuJian Weng
ACS Applied Materials & Interfaces 2017 Volume 9(Issue 8) pp:
Publication Date(Web):February 2, 2017
DOI:10.1021/acsami.6b15016
Because of its promising properties, honeycomb macroporous pattern (HMP) film has attracted increasing attention. It has been realized in many artificial nanomaterials, but the formation of these HMPs was attributed to templates or polymer/supermolecule/surfactant assistant assembly. Pure metal HMP film has been difficult to produce using a convenient colloidal template-free method. In this report, a unique template-free approach for preparation of Au HMP film with high transparency and conductivity is presented. Ultrathin Au nanowires, considered a linear polymer analogue, are directly assembled into HMP film on various substrates using a traditional static breath figure method. Subsequent chemical cross-linking and oxygen plasma treatment greatly enhance the stability and conductivity of the HMP film. The resulting HMP film exhibits great potential as an ideal candidate for transparent flexible conductive nanodevices.Keywords: breath figure array; honeycomb macroporous pattern; self-assembly; transparent and conductive film; ultrathin gold nanowires;
Co-reporter:Jian Peng, Jian Weng
Biosensors and Bioelectronics 2017 Volume 89(Part 1) pp:652-658
Publication Date(Web):15 March 2017
DOI:10.1016/j.bios.2015.12.034
•High peroxidase-like activity of MoS2/GO.•Synergistic interaction of two components.•Light enhances peroxidase-like activity of MoS2/GO.•High sensitive and selective glucose detection.Construction of novel enzyme-free mimetic is very important in improving the sensitivity of biosensor. Here, an intrinsic peroxidase-like activity of MoS2 and graphene oxide (MoS2/GO) hybrid is demonstrated and the hybrid is also used to detect glucose with high sensitivity. Firstly, the peroxidase-like activity of hydrid is compared with that of two components alone, the mixture of two components and horseradish peroxidase. The results show that the hydrid has highest catalytic activity and the Michaelis constant of this hybrid is 4.35 times lower and the maximal reaction velocity is 3.34 times higher than those of horseradish peroxidase, respectively. Electrochemical technologies are used to investigate the enhancing mechanism. The results show that the excellently catalytic performance could be attributed to the fast electron transfer on the surface of MoS2/GO and the synergistic interaction of two components. Secondly, the effect of visible light and near-infrared light on the peroxidase-like activity of hybrid is also investigated. The results show that the limit of detection for H2O2 can be reduced from 10 nM to 2.5 nM with visible light. Thirdly, the hybrid is further used to detect glucose in serum with and without light. The results show that the hybrid has high selectivity and sensitivity for glucose detection in serum and the limit of detection for glucose is reduced from 0.83 μM to 65 nM with visible light. Therefore, the hybrid may have a potential application in glucose detection in serum with high sensitivity and selectivity.
Co-reporter:Lian Wang, Qingchi Xu, Jun Xu and Jian Weng
RSC Advances 2016 vol. 6(Issue 73) pp:69033-69039
Publication Date(Web):14 Jul 2016
DOI:10.1039/C6RA13646J
Zeolitic imidazolate framworks-8 (ZIF-8) and two-dimensional black phosphorus (BP) are frequently studied for their outstanding properties and wide applications. Therefore, integrating these two components into hybrid nanocomposites is conceivable to build a hybrid nanomaterial with enhanced or even new properties. In this paper, a novel hybrid nanocomposite of ZIF-8 with few-layer two-dimensional (FL-BP) (ZIF-8/BP) is prepared for the first time. The obtained ZIF-8/BP hybrid composites are composed of ZIF-8 nanoparticles uniformly distributed over the whole BP nanosheets. The in situ growth of ZIF-8 is attributed to FL-BP functionalized with polyvinylpyrrolidone (PVP), whose pyrrolidone rings (CO) enhance the affinity between Zn ions and FL-BP, and in turn facilitate ZIF-8 in situ growth on the surface of BP. Furthermore, the obtained ZIF-8/BP hybrid nanocomposites demonstrate enhanced photocatalytic performance, for the highly efficient charge separation and transfer during photocatalytic reactions.
Co-reporter:Ming Xu, Jianqiang Zhu, Fanfan Wang, Yunjing Xiong, Yakun Wu, Qiuquan Wang, Jian Weng, Zhihong Zhang, Wei Chen, and Sijin Liu
ACS Nano 2016 Volume 10(Issue 3) pp:3267
Publication Date(Web):February 8, 2016
DOI:10.1021/acsnano.6b00539
The unique physicochemical properties of two-dimensional (2D) graphene oxide (GO) could greatly benefit the biomedical field; however, recent research demonstrated that GO could induce in vitro and in vivo toxicity. We determined the mechanism of GO induced toxicity, and our in vitro experiments revealed that pristine GO could impair cell membrane integrity and functions including regulation of membrane- and cytoskeleton-associated genes, membrane permeability, fluidity and ion channels. Furthermore, GO induced platelet depletion, pro-inflammatory response and pathological changes of lung and liver in mice. To improve the biocompatibility of pristine GO, we prepared a series of GO derivatives including aminated GO (GO-NH2), poly(acrylamide)-functionalized GO (GO-PAM), poly(acrylic acid)-functionalized GO (GO-PAA) and poly(ethylene glycol)-functionalized GO (GO-PEG), and compared their toxicity with pristine GO in vitro and in vivo. Among these GO derivatives, GO-PEG and GO-PAA induced less toxicity than pristine GO, and GO-PAA was the most biocompatible one in vitro and in vivo. The differences in biocompatibility were due to the differential compositions of protein corona, especially immunoglobulin G (IgG), formed on their surfaces that determine their cell membrane interaction and cellular uptake, the extent of platelet depletion in blood, thrombus formation under short-term exposure and the pro-inflammatory effects under long-term exposure. Overall, our combined data delineated the key molecular mechanisms underlying the in vivo and in vitro biological behaviors and toxicity of pristine GO, and identified a safer GO derivative that could be used for future applications.Keywords: biocompatibility; biological mechanisms; derivatives; graphene oxide; surface modification
Co-reporter:Jian Weng, Jian Peng, Nan Hu, Liping Sun
Nanomedicine: Nanotechnology, Biology and Medicine 2016 Volume 12(Issue 2) pp:465
Publication Date(Web):February 2016
DOI:10.1016/j.nano.2015.12.055
Co-reporter:Jian Peng, Jian Weng
Carbon 2015 Volume 94() pp:568-576
Publication Date(Web):November 2015
DOI:10.1016/j.carbon.2015.07.035
Hybrids of graphene and other two-dimensional materials have shown extraordinary properties. However, the current preparation method, chemical vapor deposition, suffers from the disadvantages of low throughput and high cost, and the produced solid hybrids are unsuitable for those applications in aqueous solution. Therefore, it is very important to find a facile method to prepare these hybrids in solution. Here, a hybrid of MoS2 and graphene oxide (GO) (MoS2/GO) is prepared by a one-pot liquid-phase-exfoliation process. The exfoliated MoS2 by ultrasound waves is stabilized by amphiphilic GO in aqueous solution. The size of GO plays an important role in tuning the structure of MoS2/GO. Ultraviolet–visible absorption spectrum, dynamic light scattering, scanning electron microscope, transmission electron microscope and atomic force microscope are used to characterize the structure of MoS2/GO produced by fractional centrifugation after exfoliation of MoS2 in GO suspension. The results indicate that GO is adhered to the surface of MoS2 to stabilize MoS2/GO in solution. Furthermore, this preparation method can also be used to prepare the hybrids of GO and other two-dimensional materials.
Co-reporter:Liping Sun;Nan Hu;Jian Peng;Liyu Chen
Advanced Functional Materials 2014 Volume 24( Issue 44) pp:6905-6913
Publication Date(Web):
DOI:10.1002/adfm.201402191
Ultrasensitive detection of nucleic acid has attracted considerable attention recently in academic research and clinic diagnostics. Current approaches for DNA analysis involve complicated or expensive processes for labeling and often yield a high detection limit. In this study, a hydrogel electrode prepared from graphene oxide and fish sperm DNA is used for label−free mitochondrial DNA detection by impedimetric approach. The hydrogel has a bionic structure containing rich water and natural biomolecule fish sperm DNA that would benefit the adsorption and hybridization of DNA. Graphene oxide is a semiconductor and its conductivity can be improved by doping negatively charged DNA molecules. The result shows that the conductivity and impedance change of hydrogel electrode could be tuned by its length and component. The linear range for DNA detection by the optimized hydrogel is from 1.0 × 10−9 to 1.0 × 10−20 M with a detection limit of 1.0 × 10−20 M. The result is ascribed to the bionic structure and tunable conductivity of hydrogel electrode. The hydrogel electrode has been used to detect the real DNA samples from patients of ovarian cancer with satisfactory results.
Co-reporter:Zhenbing Wang, Xincong Lv, Jian Weng
Carbon 2013 Volume 62() pp:51-60
Publication Date(Web):October 2013
DOI:10.1016/j.carbon.2013.05.051
Few-layer graphene prepared from graphite exfoliated by chitosan has a preserved structure without oxidation or destruction of the sp2 character of the carbon plane and exhibits a higher peroxidase catalytic activity than that of graphene oxide (GO) and its reduced form. The peroxidase catalytic activity of as-obtained few-layer graphene is 45 times higher than that of GO and 4 times higher than that of reduced GO with the same concentration of 30 μg mL−1 and the detection limit of hydrogen peroxide is 10 nM. The excellently catalytic performance can be attributed to the fast electron transfer on the surface of few-layer graphene, which is further confirmed by electrochemical characterization. The as-prepared few-layer graphene has been used to determine hydrogen peroxide in three real water samples with satisfactory results.
Co-reporter:Jun Dong, Jian Weng, Lizong Dai
Carbon 2013 Volume 52() pp:326-336
Publication Date(Web):February 2013
DOI:10.1016/j.carbon.2012.09.034
N-isopropylacrylamide is grafted on graphene by free radical polymerization to produce a series of graphene–poly(N-isopropylacrylamide) (PNIPAM) hybrid materials with different contents of graphene. The lower critical solution temperatures of the resulting materials have been investigated by ultraviolet–visible transmission spectroscopy. The result shows that the lower critical solution temperature of the resulting materials increases with the content of graphene increasing, and can be tuned to the human body temperature (37 °C) when the content of graphene is in the range of 10–30%, which is very important for application of the hybrid materials in biomedical field. The result is ascribed to the high surface area of graphene that could graft a large amount of PNIPAM molecules and the immobilization of one end of PNIPAM chain on the surface of graphene. To further understand the effect of graphene on the lower critical solution temperature of PNIPAM, atomic force microscopy has been used to trace the morphology change of the hybrid materials in solid state with the temperature increasing from 33 to 40 °C.
Co-reporter:Jun Dong;Jiabao Ding;Lizong Dai
Macromolecular Rapid Communications 2013 Volume 34( Issue 8) pp:659-664
Publication Date(Web):
DOI:10.1002/marc.201200814
Co-reporter:Qing Yang, Zhenbing Wang and Jian Weng
Soft Matter 2012 vol. 8(Issue 38) pp:9855-9863
Publication Date(Web):13 Aug 2012
DOI:10.1039/C2SM25938A
A facile and straightforward approach for the preparation of graphene oxide-triggered self-assembly of natural tripeptide glutathione gels with different structures is reported. The morphologies of glutathione/graphene oxide gels could be controlled by adjusting the content of graphene oxide. The growth mechanism of the gels with different structures is proposed in this paper: (1) graphene oxide serves as a template to immobilize glutathione, (2) glutathione is oxidized in situ and self-assembled into colloidal particles, (3) colloidal particles anisotropicly grow into different structures under controlled conditions. This work provides new insight for the assembly of peptides with graphene oxide, which will help the design and preparation of new biomaterials.
Co-reporter:Linfei Lai, Guoming Huang, Xiaofeng Wang, Jian Weng
Carbon 2011 Volume 49(Issue 5) pp:1581-1587
Publication Date(Web):April 2011
DOI:10.1016/j.carbon.2010.12.040
A three-dimensional (3D) Fe3O4/carbon material functionalized with amino and hydroxyl groups was synthesized by decomposing 2,4,5-trichlorophenol/ferrocene mixture in the presence of ammonia and polyethylene glycol in solvothermal conditions at 250 °C for 30 h by a one-step process. The 3D Fe3O4/carbon materials can be loaded with Pt nanoparticles without adding any reducing agent; Pt-loaded 3D Fe3O4/carbon hybrid materials have superior electrochemical catalytic activity toward methanol oxidation and the oxidation current density on them is nearly triple that on a commercial Pt/C catalyst.
Co-reporter:Jian Weng, Zhaowu Zhang, Liping Sun, Jin An Wang
Biosensors and Bioelectronics 2011 Volume 26(Issue 5) pp:1847-1852
Publication Date(Web):15 January 2011
DOI:10.1016/j.bios.2010.01.027
An electrochemical impedance method at a fixed frequency (10 Hz) is used to detect folate receptor-rich cancer cells with the interaction between folic acid immobilized on gold nanoparticles deposited on boron-doped diamond (BDD) electrode surface and its receptor over-expressed on cancer cell membrane without additional labeling. Experimental results have shown that the BDD electrode modified with folic acid can clearly denote folate receptor-rich cancer cells, such as HeLa cells, at a concentration down to 10 cells mL−1. The high sensitivity of BDD electrode is resulted from the change of field effect and surface charge density of BDD after cancer cells attachment. The BDD electrodes can be regenerated with 0.1 M citric acid/glycine/HC1 at pH 3.0 and used seven times again. Therefore, electrochemical technique with BDD electrode has been introduced for cancer cells detection and a simple method to detect folate receptor-rich cancer cells without additional labeling has been developed.
Co-reporter:Linfei Lai, Guoming Huang, Xiaofeng Wang, Jian Weng
Carbon 2010 Volume 48(Issue 11) pp:3145-3156
Publication Date(Web):September 2010
DOI:10.1016/j.carbon.2010.04.053
Homogeneous and monodisperse hollow carbon microspheres (HCMS) functionalized with amino and hydroxyl groups are synthesized by decomposing 2,4,6-tribromophenol/ferrocene mixture in the presence of ammonia via a one-step solvothermal process at 250 °C for 24 h. The effect of experimental conditions on the morphology of carbon microspheres has been investigated systematically. The surface of the HCMS is modified with amino and hydroxyl groups through the synthesis process as confirmed by infra-red spectroscopy and X-ray photoelectron spectroscopy. The pore-size distribution and the specific area of macropores are measured by nitrogen adsorption–desorption and mercury intrusion porosimetry. The as-synthesized HCMS has the high Brunauer–Emmett–Teller surface area of 289 m2/g and macropores whose diameter is mostly larger than 100 nm. To investigate the chemical reactivity of functionalized groups on the surface of HCMS, Au and Ag nanoparticles are successfully loaded onto HCMS by direct reduction of HAuCl4 or AgNO3 without adding any reducing agent.
Co-reporter:J. Xu;S. Li;J. Weng;X. Wang;Z. Zhou;K. Yang;M. Liu;X. Chen;Q. Cui;M. Cao;Q. Zhang
Advanced Functional Materials 2008 Volume 18( Issue 2) pp:277-284
Publication Date(Web):
DOI:10.1002/adfm.200700123
Abstract
We have successfully controlled the shape of gold nanocrystals through a simple and low-cost hydrothermal method based on a modified polyol process. Well-defined gold nanocrystals of icosahedral shape were synthesized in high yields by the rapid reduction of gold precursors with ethylene glycol (EG) in the presence of poly(vinyl pyrrolidone) (PVP) under hydrothermal conditions for 1 h. Truncated icosahedra (football-shaped) have been prepared for the first time by prolonging the reaction time to 4 h. Both nanocrystal shapes were obtained quantitatively. Addition of citric acid inhibits the shape-change process (from icosahedron to truncated icosahedron) by blocking oxidative etching, while addition of Fe(III) facilitates the shape-change process by enhancing oxidative etching. We propose that growth of truncated icosahedra can be induced and maintained through interplay of the following processes: generation of multiple twinned seeds, shape- and size-focusing by Ostwald ripening, and oxidative etching and preferential growth on the {100} face.
Co-reporter:Xiaofeng Wang;Xiaoqing Liu;Linfei Lai;Siyue Li;Zhimin Zhou;Qiang Cui;Xin Chen;Minyuan Cao;Qiqing Zhang
Advanced Functional Materials 2008 Volume 18( Issue 12) pp:1809-1823
Publication Date(Web):
DOI:10.1002/adfm.200701020
Abstract
Amine-modified carbon micro/sub-microtubes that encapsulate magnetite cores have been synthesized by decomposing a ferrocene/hexabromobenzene mixture in the presence of ammonia under solvothermal conditions at 250 °C for 24 h in a one-step process. The as-prepared carbon microstructures (NH2-ME-CMTs) were 90–2000 nm in diameter and from tens to hundreds of micrometers in length that could be tuned in various solvents. The surface of the carbon microtubes can be modified with amino groups by the synthetic process, as confirmed by infra-red (IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). Ammonia in the reaction system plays a key role in the formation of the microtube morphology and was the source of the surface functionalization groups. Fluorescent fluorescein isothiocyanate (FITC) was selected as a model compound and successively attached to the amino groups of the carbon microtubes. This result confirms the reactivity of the amino groups on the surface of the carbon microtubes. The inner magnetite cores were removed after immersion in 1 M HCl solution at room temperature over two months, and hollow carbon microtubes (NH2-H-CMTs) were obtained. The magnetite-encapsulated carbon microtubes and the hollow carbon microtubes were coated on gold electrodes to prepare carbon microtube-modified gold electrodes. The two electrodes have been used to investigate the oxidative properties of dopamine (DA) and ascorbic acid (AA). Different from the magnetite-encapsulated microtube-modified electrode, the hollow microtube-modified electrode can be utilized in the selective detection of DA in the presence of a large excess of AA. The electrochemical behaviour of DA and AA on the hollow carbon microtubes modified with amino groups is similar to that on carbon nanotubes. This result suggests that the one-step synthesis method will not change the electrochemical properties or break the backbone structure of the carbon microtubes.
Co-reporter:Jian Weng, Jianfeng Zhang, Hui Li, Liping Sun, Chenghong Lin and Qiqing Zhang
Analytical Chemistry 2008 Volume 80(Issue 18) pp:7075
Publication Date(Web):August 16, 2008
DOI:10.1021/ac800610z
An electrochemical biosensor using a boron-doped diamond (BDD) electrode is described for differentiating between gene sequences according to DNA hybridization events using an ac impedimetric approach. BDD electrodes were dipped into a 1% solution of polyethylenimine (PEI) to adsorb a thin layer of positively charged PEI on the surface of BDD, then PEI-modified BDD electrodes were used to immobilize negatively charged single-stranded PCR fragments from Exon 7 of human p53 gene. Alternating current impedimetric measurements were first performed on these systems in phosphate buffered saline (PBS) and then upon exposure to single-stranded DNA (ssDNA). When the ssDNA-immobilized BDD electrode and solution ssDNA were completely complementary, a large drop in impedance was measured. Complementary DNA could be clearly detected at concentrations down to 10−19 g mL−1 at a fixed frequency (10 Hz). Higher concentrations of DNA gave faster hybridization with saturation occurring at levels above 1.0 pg mL−1. Responses were much lower upon exposure to noncDNA, even at higher concentrations. The results show it is possible to directly detect target DNA at a fixed frequency and without additional labeling.
Co-reporter:J. Weng;J. Xue;J. Wang;J. Ye;H. Cui;F. Sheu;Q. Zhang
Advanced Functional Materials 2005 Volume 15(Issue 4) pp:
Publication Date(Web):23 MAR 2005
DOI:10.1002/adfm.200400049
Gold clusters have been electrodeposited on a boron-doped diamond (BDD) electrode by scanning the potential from 0.7 V to 0.0 V (vs. 3 M KCl-Ag/AgCl reference) in a solution of 0.5 mM KAuCl4 and 1.0 M KCl. The cluster-modified diamond (Au/BDD) electrode has been used to investigate the oxidative properties of dopamine (DA) and ascorbate (AA). The modified diamond electrode shows a higher activity for DA oxidation than AA; the oxidation potential of DA shifted to a less-positive potential (0.11 V) than that of AA, which oxidized at 0.26 V, and DA possesses a much higher peak current than that of AA. The reversibility of the electrode reaction with DA is significantly improved at the Au/BDD electrode, which results in a large increase in the square-wave voltammetric peak current, with a detection limit of 0.1 μM in the presence of a large excess of AA. The Au/BDD electrode shows excellent sensitivity and good selectivity for DA detection. A self-assembled monolayer (SAM) of mercaptoacetic acid on the Au clusters was used to provide an antifouling effect as the negative CO2– groups repulse negative ascorbate and attract positive dopamine in pH 7.4 buffer. After pre-absorption, the SAM/Au/BDD electrode could detect 1.0 nM DA in a linear range from 10 nM to 10 μM in the presence of 10–4 M AA.
Co-reporter:Jian Weng;Qiqing Zhang
Journal of Polymer Science Part A: Polymer Chemistry 2005 Volume 43(Issue 22) pp:5414-5428
Publication Date(Web):29 SEP 2005
DOI:10.1002/pola.20960
We synthesized a series of cyclens substituted with mixed stilbene and poly(ethylene glycol) dendritic arms. All dendrimers terminated with different peripheral groups had good solubility in common organic solvents, and dendrimers terminated with CO2H groups (CO2H-dendrimers) were also soluble in alkaline solutions. The nickel coordination properties of these dendrimers were investigated in organic solvents. Dendrimers terminated with CN groups (CN-dendrimers) and the second-generation CO2H-dendrimer [(CO2H)8L2] could produce pentacoordinated nickel complexes; the third-generation CO2H-dendrimer [(CO2H)16L3] could form tetra- and pentacoordinated nickel complexes, and the nickel complex of the fourth-generation CO2H-dendrimer [(CO2H)32L4] could not be obtained. This result was due to the fact that the globular surface of (CO2H)16L3 formed a hydrogen-bond network that selectively penetrated cations and inhibited the access of anions to the core. The formation of the hydrogen-bond network was confirmed by Fourier transform infrared, 1H NMR, and fluorescence data. The CN-dendrimers could not form hydrogen bonds on the surface, and the first- and second-generation CO2H-dendrimers could not form intramolecular hydrogen-bond networks. Therefore, they had no selectivity for positive nickel ions and negative chloride ions. (CO2H)32L4 could not produce a nickel complex because it had a crammed backbone structure that could not penetrate nickel and chloride ions. Therefore, it was possible to control the ion access of cations and anions with the hydrogen-bond network of (CO2H)16L3. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5414–5428, 2005
