Co-reporter:Ruilong Zhang; Jun Zhao; Guangmei Han; Zhengjie Liu; Cui Liu; Cheng Zhang; Bianhua Liu; Changlong Jiang; Renyong Liu; Tingting Zhao; Ming-Yong Han
Journal of the American Chemical Society 2016 Volume 138(Issue 11) pp:3769-3778
Publication Date(Web):March 3, 2016
DOI:10.1021/jacs.5b12848
Fluorescent probes are powerful tools for the investigations of reactive oxygen species (ROS) in living organisms by visualization and imaging. However, the multiparallel assays of several ROS with multiple probes are often limited by the available number of spectrally nonoverlapping chromophores together with large invasive effects and discrepant biological locations. Meanwhile, the spontaneous ROS profilings in various living organs/tissues are also limited by the penetration capability of probes across different biological barriers and the stability in reactive in vivo environments. Here, we report a single fluorescent probe to achieve the effective discrimination and profiling of hydroxyl radicals (•OH) and hypochlorous acid (HClO) in living organisms. The probe is constructed by chemically grafting an additional five-membered heterocyclic ring and a lateral triethylene glycol chain to a fluorescein mother, which does not only turn off the fluorescence of fluorescein, but also create the dual reactive sites to ROS and the penetration capability in passing through various biological barriers. The reactions of probe with •OH and HClO simultaneously result in cyan and green emissions, respectively, providing the real-time discrimination and quantitative analysis of the two ROS in cellular mitochondria. Surprisingly, the accumulation of probes in the intestine and liver of a normal-state zebrafish and the transfer pathway from intestine-to-blood-to-organ/tissue-to-kidney-to-excretion clearly present the profiling of spontaneous •OH and HClO in these metabolic organs. In particular, the stress generation of •OH at the fresh wound of zebrafish is successfully visualized for the first time, in spite of its extremely short lifetime.
Co-reporter:Yahui Wang, Cheng Zhang, Xiaochun Chen, Bo Yang, Liang Yang, Changlong Jiang and Zhongping Zhang
Nanoscale 2016 vol. 8(Issue 11) pp:5977-5984
Publication Date(Web):19 Feb 2016
DOI:10.1039/C6NR00430J
A simple and effective ratiometric fluorescence nanosensor for the selective detection of Cu2+ has been developed by covalently connecting the carboxyl-modified red fluorescent cadmium telluride (CdTe) quantum dots (QDs) to the amino-functionalized blue fluorescent carbon nanodots (CDs). The sensor exhibits the dual-emissions peaked at 437 and 654 nm, under a single excitation wavelength of 340 nm. The red fluorescence can be selectively quenched by Cu2+, while the blue fluorescence is a internal reference, resulting in a distinguishable fluorescence color change from pink to blue under a UV lamp. The detection limit of this highly sensitive ratiometric probe is as low as 0.36 nM, which is lower than the U.S. Environmental Protection Agency (EPA) defined limit (20 μM). Moreover, a paper-based sensor has been prepared by printing the hybrid carbon dots–quantum dots probe on a microporous membrane, which provides a convenient and simple approach for the visual detection of Cu2+. Therefore, the as-synthesized probe shows great potential application for the determination of Cu2+ in real samples.
Co-reporter:Qingsong Mei, Jian Chen, Jun Zhao, Liang Yang, Bianhua Liu, Renyong Liu, and Zhongping Zhang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 11) pp:7390
Publication Date(Web):February 29, 2016
DOI:10.1021/acsami.6b00791
Graphene oxide (GO) has been widely used as a fluorescence quencher, but its luminescent properties, especially tailor-made controlling emission colors, have been seldom reported due to its heterogeneous structures. Herein, we demonstrated a novel chemical oxidative strategy to tune GO emissions from brown to cyan without changing excitation wavelength. The precise tuning is simply achieved by varying reaction times of GO nanosheets in piranha solution, but there is no need for complex chromatography separation procedures. With increasing reaction times, oxygen content on the lattice of GO nanosheets increased, accompanied by the diminution of their sizes and sp2 conjugation system, resulting in an increase of emissive carbon cluster-like states. Thereby, the luminescent colors of GO were tuned from brown to yellow, green, and cyan, and its fluorescent quantum yields were enhanced. The obtained multicolored fluorescent GO nanosheets would open plenty of novel applications in cellular imaging and multiplex encoding analysis.Keywords: atomic oxygen; cellular imaging; emissive carbon cluster; graphene oxide; multicolored emission;
Co-reporter:Yujie Zhou, Xiaoyan Huang, Cui Liu, Ruilong Zhang, Xiaoling Gu, Guijian Guan, Changlong Jiang, Liying Zhang, Shuhu Du, Bianhua Liu, Ming-Yong Han, and Zhongping Zhang
Analytical Chemistry 2016 Volume 88(Issue 12) pp:6105
Publication Date(Web):May 27, 2016
DOI:10.1021/acs.analchem.6b01248
Fluorescent colorimetry test papers are promising for the assays of environments, medicines, and foods by the observation of the naked eye on the variations of fluorescence brightness and color. Unlike dye-absorption-based pH test paper, however, the fluorescent test papers with wide color-emissive variations with target dosages for accurate quantification remain unsuccessful even if the multicolorful fluorescent probes are used. Here, we report the dosage-sensitive fluorescent colorimetry test paper with a very wide/consecutive “from red to cyan” response to the presence and amount of arsenic ions, As(III). Red quantum dots (QDs) were modified with glutathione and dithiothreitol to obtain the supersensitivity to As(III) by the quenching of red fluorescence through the formation of dispersive QDs aggregates. A small amount of cyan carbon dots (CDs) with spectral blue-green components as the photostable internal standard were mixed into the QDs solution to produce a composited red fluorescence. Upon the addition of As(III) into the sensory solution, the fluorescence color could gradually be reversed from red to cyan with a detection limit of 1.7 ppb As(III). When the sensory solution was printed onto a piece of filter paper, surprisingly a serial of color evolution from peach to pink to orange to khaki to yellowish to yellow-green to final cyan with the addition of As(III) was displayed and clearly discerned the dosage scale as low as 5 ppb. The methodology reported here opens a novel pathway toward the real applications of fluorescent test papers.
Co-reporter:Ruilong Zhang, Shijiang Liu, Jianping Wang, Guangmei Han, Linlin Yang, Bianhua Liu, Guijian Guan and Zhongping Zhang
Analyst 2016 vol. 141(Issue 16) pp:4919-4925
Publication Date(Web):31 May 2016
DOI:10.1039/C6AN00830E
Luminescent chemosensors for hydrogen sulphide (H2S) are of great interest because of the close association of H2S with our health. However, current probes for H2S detection have problems such as low sensitivity/selectivity, poor aqueous-solubility or interference from background fluorescence. This study reports an ultrasensitive and time-gated “switch on” probe for detection of H2S, and its application in test paper for visualization of exhaled H2S. The complex probe is synthesized with a luminescent Tb3+ centre and three ligands of azido (–N3) substituted pyridine-2,6-dicarboxylic acid, giving the probe high hydrophilicity and relatively fast reaction dynamics with H2S because there are three –N3 groups in each molecule. The introduced –N3 group as a strong electron-withdrawing moiety effectively changes the energy level of ligand via intramolecular charge transfer (ICT), and thus breaks the energy transferring from ligand to lanthanide ion, resulting in quenching of Tb3+ luminescence. On addition of H2S, the –N3 group can be reduced to an amine group to break the process of ICT, and the luminescence of Tb3+ is recovered at a nanomolar sensitivity level. With a long lifetime of luminescence of Tb3+ centre (1.9 ms), use of a time-gated technique effectively eliminates the background fluorescence by delaying fluorescence collection for 0.1 ms. The test paper imprinted by the complex probe ink can visualize clearly the trace H2S gas exhaled by mice.
Co-reporter:Xiaoyan Huang, Yujie Zhou, Cui Liu, Ruilong Zhang, Liying Zhang, Shuhu Du, Bianhua Liu, Ming-Yong Han, Zhongping Zhang
Biosensors and Bioelectronics 2016 Volume 86() pp:530-535
Publication Date(Web):15 December 2016
DOI:10.1016/j.bios.2016.07.021
•A single nanofluorophore probe with the dual-emissive intensities was designed.•The ratiometric probe produced the wide/consecutive color variations by analyte.•High-quality fluorescent colorimetric test papers sensitively responded to glucose.•The test papers gave a clear judgment whether blood glucose is at a normal level.Fluorescent test papers are promising for the wide applications in the assays of diagnosis, environments and foods, but unlike classical dye-absorption-based pH test paper, they are usually limited in the qualitative yes/no type of detection by fluorescent brightness, and the colorimetry-based quantification remains a challenging task. Here, we report a single dual-emissive nanofluorophore probe to achieve the consecutive color variations from blue to red for the quantification of blood glucose on its as-prepared test papers. Red quantum dots were embedded into silica nanoparticles as a stable internal standard emission, and blue carbon dots (CDs) were further covalently linked onto the surface of silica, in which the ratiometric fluorescence intensity of blue to red is controlled at 5:1. While the oxidation of glucose induced the formation of Fe3+ ions, the blue emission of CDs was thus quenched by the electron transfer from CDs to Fe3+, displaying a serial of consecutive color variations from blue to red with the dosage of glucose. The high-quality test papers printed by the probe ink exhibited a dosage-sensitive allochromatic capability with the clear differentiations of ~5, 7, 9, 11 mM glucose in human serum (normal: 3–8 mM). The blood glucose determined by the test paper was almost in accordance with that measured by a standard glucometer. The method reported here opens a window to the wide applications of fluorescent test paper in biological assays.
Co-reporter:Jianping Wang, Renyong Liu, Cheng Zhang, Guangmei Han, Jun Zhao, Bianhua Liu, Changlong Jiang and Zhongping Zhang
RSC Advances 2015 vol. 5(Issue 105) pp:86803-86810
Publication Date(Web):30 Sep 2015
DOI:10.1039/C5RA16558J
Chemical sensing for the convenient detection of cancer cells has been widely explored with the use of various sensing materials and techniques, but it is still a challenge to achieve ultrasensitive, simple, rapid and inexpensive detection of cancer cells. Herein, we report a surface-enhanced Raman scattering (SERS) method for the detection of cancer cells in situ. In our work, ultrathin g-C3N4 nanosheet/Au@AgNP hybrids (g-C3N4/Au@AgNPs) were fabricated using a self-assembly strategy, in which poly(ethyleneimine) (PEI) was used to obtain cationic polyelectrolyte-modified ultrathin nanosheets and anchor the Au@AgNPs. The g-C3N4 nanosheets exhibited a strong enrichment ability and the self-assembled Au@AgNPs showed an excellent SERS activity, both of which led to an ultrahigh sensitivity. The hybrids were applied to detect folic acid (FA) with the sensitive detection limit of 2.41 nM. Importantly, after being modified with FA, which targeted cancer cells with folate receptors (FRs), the formed g-C3N4/Au@AgNPs–FA was used as a SERS probe for the on-site monitoring of cancer cells with FA as the Raman reporter molecule.
Co-reporter:Cheng Zhang;Liang Yang;Jun Zhao;Bianhua Liu;Dr. Ming-Yong Han; Zhongping Zhang
Angewandte Chemie International Edition 2015 Volume 54( Issue 39) pp:11531-11535
Publication Date(Web):
DOI:10.1002/anie.201504518
Abstract
The white backlight in displays is generated by optimizing the proportions of individual emitters with different wavelengths by variations in materials composition, phase, and structure. Color pixels usually result from the separation of white light or the excitation with multiwavelength or multipulse sources. However, it is a challenge to develop a material that comprises a single structure and emits over the full visible spectrum, but where the emission wavelengths can be controlled by a simple excitation source. Herein, we report an upconversion nanostructure that incorporates several lanthanide ions in the same core@shell@shell structure. The combination of multiple narrow spectral bands results in the emission of white light. The emission colors can be tuned by changing the excitation power density, which manipulates the photon transfer pathways. Applications such as flat-panel displays and imaging have been demonstrated.
Co-reporter:Cheng Zhang;Liang Yang;Jun Zhao;Bianhua Liu;Dr. Ming-Yong Han; Zhongping Zhang
Angewandte Chemie 2015 Volume 127( Issue 39) pp:11693-11697
Publication Date(Web):
DOI:10.1002/ange.201504518
Abstract
The white backlight in displays is generated by optimizing the proportions of individual emitters with different wavelengths by variations in materials composition, phase, and structure. Color pixels usually result from the separation of white light or the excitation with multiwavelength or multipulse sources. However, it is a challenge to develop a material that comprises a single structure and emits over the full visible spectrum, but where the emission wavelengths can be controlled by a simple excitation source. Herein, we report an upconversion nanostructure that incorporates several lanthanide ions in the same core@shell@shell structure. The combination of multiple narrow spectral bands results in the emission of white light. The emission colors can be tuned by changing the excitation power density, which manipulates the photon transfer pathways. Applications such as flat-panel displays and imaging have been demonstrated.
Co-reporter:Yingchang Jiang, Shudong Zhang, Qi Ji, Jian Zhang, Zhongping Zhang and Zhenyang Wang
Journal of Materials Chemistry A 2014 vol. 2(Issue 13) pp:4574-4579
Publication Date(Web):07 Jan 2014
DOI:10.1039/C3TA14838F
Ultrathin two-dimensional (2D) nanosheets are a conceptually new category of nanoscale materials. Integration/assembly of individual 2D nanosheets into 3D hierarchical structures is an enormous challenge and an essential requirement for their application. Here we first report the direct synthesis of Cu7S4 hierarchical hollow cubic cages assembled by ultrathin nanosheets based on the Kirkendall effect. Slowly released Cu+ from Cu2O cubic template-crystals and S2− from decomposed thioacetamide (TAA) can react with each other and form a diffusion pair, which provides a thermodynamic and kinetic equilibrium to be responsible for the formation of ultrathin Cu7S4 nanosheets and the Cu7S4 hierarchical hollow cubic cages. Using this unique hollow structure and the outstanding catalytic property of the Cu7S4 nanosheets, as an example, we successfully demonstrate that Cu7S4 nanocages can effectively catalyse the “clock reaction”, which is a periodic cycle redox oscillation reaction between methylene blue (MB) and colorless leucomethylene blue (LMB). The unique hierarchical structure has been found to enhance the rate of this redox reaction via the ultrathin nanocatalyst. This work develops a facile strategy for synthesizing 3D hierarchical structures constructed by ultrathin nanosheets and demonstrates their superior ability to optimize the nanosheet-catalyzed clock reaction.
Co-reporter:Jian Zhang, Jianping Wang, Liang Yang, Bianhua Liu, Guijian Guan, Changlong Jiang and Zhongping Zhang
Chemical Communications 2014 vol. 50(Issue 100) pp:15870-15873
Publication Date(Web):16 Oct 2014
DOI:10.1039/C4CC07430K
A facile ligand replacement induced chemiluminescence method is developed for selective detection of the organophosphorus pesticide parathion-methyl based on the use of bifunctional Au–Fe3O4 dumbbell-like nanoparticles to overcome the interference from coexisting substances in a real sample.
Co-reporter:Chao Yuan, Bianhua Liu, Fei Liu, Ming-Yong Han, and Zhongping Zhang
Analytical Chemistry 2014 Volume 86(Issue 2) pp:1123
Publication Date(Web):December 30, 2013
DOI:10.1021/ac402894z
A new “turn on” fluorescence nanosensor for selective Hg2+ determination is reported based on bis(dithiocarbamato)copper(II) functionalized carbon nanodots (CuDTC2-CDs). The CuDTC2 complex was conjugated to the prepared amine-coated CDs by the condensation of carbon disulfide onto the nitrogen atoms in the surface amine groups, followed by the coordination of copper(II) to the resulting dithiocarbamate groups (DTC) and finally by the additional coordination of ammonium N-(dithicarbaxy) sarcosine (DTCS) to form the CuDTC2-complexing CDs. The CuDTC2 complex at surface strongly quenched the bright-blue fluorescence of the CDs by a combination of electron transfer and energy transfer mechanism. Hg2+ could immediately switch on the fluorescence of the CuDTC2-CDs by promptly displacing the Cu2+ in the CuDTC2 complex and thus shutting down the energy transfer pathway, in which the sensitive limit for Hg2+ as low as 4 ppb was reached. Moreover, a paper-based sensor has been fabricated by printing the CuDTC2-CDs probe ink on a piece of cellulose acetate paper using a commercial inkjet printer. The fluorescence “turn on” on the paper provided the most conveniently visual detection of aqueous Hg2+ ions by the observation with naked eye. The very simple and effective strategy reported here facilitates the development of portable and reliable fluorescence nanosensors for the determination of Hg2+ in real samples.
Co-reporter:Jianping Wang, Liang Yang, Bianhua Liu, Haihe Jiang, Renyong Liu, Jingwei Yang, Guangmei Han, Qingsong Mei, and Zhongping Zhang
Analytical Chemistry 2014 Volume 86(Issue 7) pp:3338
Publication Date(Web):March 10, 2014
DOI:10.1021/ac403409q
An electronic nose can detect highly volatile chemicals in foods, drugs, and environments, but it is still very much a challenge to detect the odors from crystalline compounds (e.g., solid explosives) with a low vapor pressure using the present chemosensing techniques in such way as a dog’s olfactory system can do. Here, we inkjet printed silver nanoparticles (AgNPs) on cellulose paper and established a Raman spectroscopic approach to detect the odors of explosive trinitrotoluene (TNT) crystals and residues in the open environment. The layer-by-layer printed AgNP paper was modified with p-aminobenzenethiol (PABT) for efficiently collecting airborne TNT via a charge-transfer reaction and for greatly enhancing the Raman scattering of PABT by multiple spectral resonances. Thus, a Raman switch concept by the Raman readout of PABT for the detection of TNT was proposed. The AgNPs paper at different sites exhibited a highly uniform sensitivity to TNT due to the layer-by-layer printing, and the sensitive limit could reach 1.6 × 10–17 g/cm2 TNT. Experimentally, upon applying a beam of near-infrared low-energy laser to slightly heat (but not destruct) TNT crystals, the resulting airborne TNT in the open environment was probed at the height of 5 cm, in which the concentration of airborne species was lower than 10 ppt by a theoretical analysis. Similarly, the odors from 1.4 ppm TNT in soil and 7.2, 2.9, and 5.7 ng/cm2 TNT on clothing, leather, and envelope, respectively, were also quickly sensed for 2 s without destoying these inspected objects.
Co-reporter:Changlong Jiang, Yubian Han, Shengjun Liu and Zhongping Zhang
CrystEngComm 2014 vol. 16(Issue 6) pp:952-958
Publication Date(Web):04 Dec 2013
DOI:10.1039/C3CE42124D
We have developed a direct and scalable approach, based upon a thermal decomposition method under normal atmospheric pressure via an interface diffusion mechanism, for growing well-defined single-crystalline functional metal oxide nanobelts. Several metal oxide nanobelts including magnetic oxides, transparent conducting oxides, and other functional oxides can be synthesized on a large scale. The typical synthesis strategy involves the synthesis of the precursors via a solvothermal process and subsequently the fabrication of the nanobelts through thermal decomposition of the precursors at atmospheric pressure, and the sizes (the length and the width) of nanobelts can be easily tuned by modifying the heating temperature and the heating rate. This synthetic strategy might not only shed a new light on the facile, general synthesis and functional mechanisms of the functional metal oxide nanobelts, but also extend the practical applications of the nanobelts in a variety of fields.
Co-reporter:Yingchang Jiang, Shudong Zhang, Jian Zhang, Zhongping Zhang and Zhenyang Wang
CrystEngComm 2014 vol. 16(Issue 38) pp:8977-8983
Publication Date(Web):09 Jul 2014
DOI:10.1039/C4CE01024H
Surface-modification at the interface between inorganic surfaces and organic molecules plays a critical role in the growth of inorganic nanocrystals on prepatterned and flat/curved substrates. Herein, we have developed a general and versatile method for inducing the nucleation and growth of chalcogenide nanostructures on Si substrates by surface-modification. Monolayers of 3-mercaptopropyltriethoxysilane (3-MPTES) were used to induce the nucleation and growth of chalcogenide nanostructures from an aqueous solution at near room temperature. Terminal sulfhydryl groups (–SH) act as nucleation sites because of their strong coordination capacity to bind metal ions. Once the initial nuclei are formed on the surface of the Si substrate, the chalcogenide nanostructures can be formed through an ion-by-ion growth via ion diffusion in the liquid medium, resulting in the formation of a dense/stable layer of chalcogenide nanostructures. Meanwhile, the intercrystalline distances between the chalcogenide nanostructures can be adjusted by the surface density of 3-MPTES modified on the substrates. Furthermore, the present surface-modification strategy shows extremely mild growth conditions and good reproducibility. This inducing nucleation and growth strategy can be extended to fabricate other chalcogenide nanocrystals, including PbS nanocubes, Ag2S nanoparticals, CdS spherulites and Fe8S7 nanobelts, on silicon wafers. These substrate-arrays with semiconducting chalcogenide nanostructures can be used for the nanofabrication of electrodes, and electronic and nanophotonic devices.
Co-reporter:Yubian Han, Shengjun Liu, Bianhua Liu, Changlong Jiang and Zhongping Zhang
RSC Advances 2014 vol. 4(Issue 6) pp:2776-2782
Publication Date(Web):27 Nov 2013
DOI:10.1039/C3RA44377A
Analytical techniques based on surface-enhanced Raman scattering (SERS) suffer from a lack of reproducibility and reliability, thus hampering their practical applications. Herein, we have developed SiO2@Ag nanospheres as an effective SERS detection platform through in situ loading Ag nanocontacts onto the SiO2 nanospheres, the well-designed and uniform nanocomposites provide highly enhanced effects for the tremendous SERS signal amplification. The huge enhanced effect might originate from the hot spots generated from the nanocontacts among the silver nanoparticles loaded onto the silica nanosphere, and also possibly from the nanogaps among the neighboring silver nanoparticles between the two silica nanospheres. The SERS enhancement factor of the SiO2@Ag nanospheres substrate is as high as 1016. Moreover, the as-fabricated SERS substrate can be employed to enhance the Raman signals of some chemicals that are harmful to environment including thiram, melamine and ethyl-parathion. The detection limits with the SERS platform are several orders of magnitude lower than the maximal residue limit (MRL) in fruit prescribed by U.S. Environmental Protection Agency (EPA). Therefore the surface lifting spectroscopic technique based on the SiO2@Ag nanosphere SERS platform offers great practical potential for the on-site assessment and identification of harmful chemicals with ultralow concentrations in agricultural products and environments.
Co-reporter:Liying Zhang, Yang Jin, Hui Mao, Lei Zheng, Jiawei Zhao, Yan Peng, Shuhu Du, Zhongping Zhang
Biosensors and Bioelectronics 2014 Volume 58() pp:165-171
Publication Date(Web):15 August 2014
DOI:10.1016/j.bios.2014.02.052
•We developed a structure-selective hotspot Raman enhancement strategy to detect PA.•Interparticle hotspot is caused by the interaction of two carboxyls of PA with Au@Ag NPs.•The hotspot can selectively enhance the Raman signals of PA in penicillin matrix.•Rapid monitoring of allergen in penicillin will reduce the occurrence of allergic reaction.Trace penicilloic acid allergen frequently leads to various fatal immune responses to many patients, but it is still a challenge to directly discriminate and detect its residue in penicillin by a chemosensing way. Here, we report that silver-coated gold nanoparticles (Au@Ag NPs) exhibit a structure-selective hot-spot Raman enhancement capability for direct identification and detection of trace penicilloic acid in penicillin. It has been demonstrated that penicilloic acid can very easily link Au@Ag NPs together by its two carboxyl groups, locating itself spontaneously at the interparticle of Au@Ag NPs to form strong Raman hot-spot. At the critical concentration inducing the nanoparticle aggregation, Raman-enhanced effect of penicilloic acid is ~60,000 folds higher than that of penicillin. In particular, the selective Raman enhancement to the two carboxyl groups makes the peak of carboxyl group at C6 of penicilloic acid appear as a new Raman signal due to the opening of β-lactam ring of penicillin. The surface-enhanced Raman scattering (SERS) nanoparticle sensor reaches a sensitive limit lower than the prescribed 1.0‰ penicilloic acid residue in penicillin. The novel strategy to examine allergen is more rapid, convenient and inexpensive than the conventional separation-based assay methods.
Co-reporter:Liang Yang;Ruilong Zhang;Bianhua Liu;Jianping Wang;Suhua Wang;Dr. Ming-Yong Han; Zhongping Zhang
Angewandte Chemie 2014 Volume 126( Issue 38) pp:10273-10277
Publication Date(Web):
DOI:10.1002/ange.201405295
Abstract
Graphene oxide has widely been employed in various fields, but its structure and composition has still not been fully understood. Here we report that freshly prepared graphene oxide exhibits a large number of π-conjugated carbon radicals at its π-network plane, which result from the addition reaction of hydroxyl radicals from H2O2 onto the conjugated double bonds of graphene oxide. The π-conjugated carbon radicals can directly initiate the long-lasting visible chemiluminescence of luminol, which is even stronger than that obtained when horseradish peroxidase and H2O2 are used. Previously, graphene oxide was mainly reported to be a quencher of chemiluminescence instead. Remarkably, the reacted radicals can be regenerated, thereby enabling the repetitive initiation of chemiluminescence by re-treatment of graphene oxide. The results reported here provide a new understanding of the structure, properties, and applications of graphene oxide.
Co-reporter:Liang Yang;Ruilong Zhang;Bianhua Liu;Jianping Wang;Suhua Wang;Dr. Ming-Yong Han; Zhongping Zhang
Angewandte Chemie International Edition 2014 Volume 53( Issue 38) pp:10109-10113
Publication Date(Web):
DOI:10.1002/anie.201405295
Abstract
Graphene oxide has widely been employed in various fields, but its structure and composition has still not been fully understood. Here we report that freshly prepared graphene oxide exhibits a large number of π-conjugated carbon radicals at its π-network plane, which result from the addition reaction of hydroxyl radicals from H2O2 onto the conjugated double bonds of graphene oxide. The π-conjugated carbon radicals can directly initiate the long-lasting visible chemiluminescence of luminol, which is even stronger than that obtained when horseradish peroxidase and H2O2 are used. Previously, graphene oxide was mainly reported to be a quencher of chemiluminescence instead. Remarkably, the reacted radicals can be regenerated, thereby enabling the repetitive initiation of chemiluminescence by re-treatment of graphene oxide. The results reported here provide a new understanding of the structure, properties, and applications of graphene oxide.
Co-reporter:Lulu Zhang, Changlong Jiang and Zhongping Zhang
Nanoscale 2013 vol. 5(Issue 9) pp:3773-3779
Publication Date(Web):13 Mar 2013
DOI:10.1039/C3NR00631J
Analytical techniques based on surface-enhanced Raman scattering (SERS) suffer from a lack of reproducibility and reliability, thus hampering their practical applications. Herein, we have developed a SERS-active substrate based on a graphene oxide embedded sandwich nanostructure for ultrasensitive Raman signal readout. By using this novel Au@Ag NPs/GO/Au@Ag NPs sandwich nanostructure as a SERS substrate, the Raman signals of analytes were dramatically enhanced due to having plenty of hot spots on their surfaces and the unique structure of the graphene oxide sheets. These features make the sandwich nanostructured film an ideal SERS substrate to improve the sensitivity, reproducibility and reliability of the Raman readout. The sandwich nanostructure film can be applied to detect rhodamine-6G (R6G) with an enhancement factor (EF) of ∼7.0 × 107 and the pesticide thiram in commercial grape juice with a detection limit of as low as 0.1 μM (0.03 ppm), which is much lower than the maximal residue limit (MRL) of 7 ppm in fruit prescribed by the U.S. Environmental Protection Agency (EPA). The GO embedded sandwich nanostructure also has the ability to selectively detect dithiocarbamate compounds over other types of agricultural chemical. Furthermore, spiked tests show that the sandwich nanostructure can be used to monitor thiram in natural lake water and commercial grape juice without further treatment. In addition, the GO enhanced Raman spectroscopic technique offers potential practical applications for the on-site monitoring and assessment of pesticide residues in agricultural products and environments.
Co-reporter:Changlong Jiang, Renyong Liu, Guangmei Han and Zhongping Zhang
Chemical Communications 2013 vol. 49(Issue 59) pp:6647-6649
Publication Date(Web):04 Jun 2013
DOI:10.1039/C3CC43410A
A chemically reactive Raman probe has been developed for ultrasensitively monitoring and imaging the in vivo generation of femtomolar oxidative species as induced by anti-tumor drugs in living cells.
Co-reporter:Yuanxin Du, Renyong Liu, Bianhua Liu, Suhua Wang, Ming-Yong Han, and Zhongping Zhang
Analytical Chemistry 2013 Volume 85(Issue 6) pp:3160
Publication Date(Web):February 25, 2013
DOI:10.1021/ac303358w
The chemical sensing for the convenient detection of mercuric ion (II) (Hg2+) have been widely explored with the use of various sensing materials and techniques. It still remains a challenge to achieve ultrasensitive but simple, rapid, and inexpensive detection to metal ions. Here we report a surface-enhanced Raman scattering (SERS) chip for the femtomolar (fM) detection of Hg2+ by employing silver-coated gold nanoparticles (Au@Ag NPs) together with an organic ligand. 4,4′-Dipyridyl (Dpy) can control the aggregation of Au@Ag NPs via its dual interacting sites to Ag nanoshells to generate strong Raman hot spots and SERS readouts. However, the presence of Hg2+ can inhibit the aggregation of Au@Ag NPs by the coordination with Dpy, and as a result the SERS signals of Dpy are quenched. On the basis of these findings, a SERS chip has been fabricated by the assembly of Au@Ag NPs on a piece of silicon wafer and the further modification with Dpy. The exchange of Dpy from the chip into the aqueous Hg2+ droplet results in the quenching of Raman signals of Dpy, responding to 10 fM Hg2+ that is about 6 orders of magnitude lower than the limit defined by the U.S. Environmental Protection Agency in drinkable water. Each test using the SERS chip only needs a droplet of 20 μL sample and is accomplished within ∼4 min. The SERS chip has also been applied to the quantification of Hg2+ in milk, juice, and lake water.
Co-reporter:Liang Hong, Qingsong Mei, Lei Yang, Cheng Zhang, Renyong Liu, Mingyong Han, Ruilong Zhang, Zhongping Zhang
Analytica Chimica Acta 2013 Volume 802() pp:89-94
Publication Date(Web):13 November 2013
DOI:10.1016/j.aca.2013.10.002
•A test paper was used for visualization of explosive 2,4,6-trinitrophenol (TNP) by the naked eye.•TNP can strongly quench the phosphorescence of NaGdF4:Ce/Tb nanorods.•Polyethylenimine (PEI) molecules facilitate the formation of uniform NaGdF4 nanorods.•PEI molecules provide specific recognized sites for TNP by the acid–base pairing interaction.The facile and sensitive strategies for detections of nitroaromatic explosives are highly desirable in many challenging environments, especially for homeland security against terrorism. Here, we inkjet printed polyethylenimine (PEI)-coated Ce, Tb co-doped NaGdF4 nanorods (NaGdF4:Ce/Tb NRs) onto common filter paper to construct test paper for visual and instant detections of a typical explosive 2,4,6-trinitrophenol (TNP). Polyethylenimine molecules not only facilitate the formation of uniform NaGdF4 nanorods but also provide specific recognized sites for TNP by the acid–base pairing interaction. The resultant TNP bound at the surface of PEI-coated NaGdF4:Ce/Tb NRs can strongly quench the phosphorescence with a remarkably high quenching constant by the charge transfer mechanism from NaGdF4:Ce/Tb NRs to TNP. By printing of the probe on a piece of filter paper, trace amounts of TNP can be visually detected by the appearance of a dark color against a bright green background under a UV lamp. This test paper can detect TNP as low as 0.45 ng mm−2 by the naked eye, which provides a potential application in the rapid, on-line detections of explosives.
Co-reporter:Shudong Zhang ; Shuangshuang Wang ; Jian Zhang ; Yingchang Jiang ; Qi Ji ; Zhongping Zhang ;Zhenyang Wang
The Journal of Physical Chemistry C 2013 Volume 117(Issue 44) pp:23412-23417
Publication Date(Web):October 2, 2013
DOI:10.1021/jp408478h
Latent heat of phase change materials (PCMs) has long been regarded as constant. In this work, it is found that this parameter can be altered when they are in nanoscale. We designed and assembled a nanocapsule-confinement system with stearic acid (SA) sealed in silica nanoshells to investigate the thermodynamics and kinetics of their phase transition in nanoscale. It is interesting that heat storage capacity of the obtained SA@SiO2 nanocapsules (NCs) could be increased up to 374.2 kJ/kg, about 36.9% more than that of the unconfined SA (273.3 kJ/kg). This is because the high superimposed stress from the curvature effect inside SiO2 nanoshells would significantly shorten the intermolecular spacing of SA as compared to their unconfined state, which will especially strengthen hydrogen bonds of SA, forming multiple stable hydrogen bond networks. Therefore, breaking and reforming of these hydrogen bonds will no doubt contribute to latent heat of SA when they change from solid to liquid. Our results not only are helpful for understanding phase transition behaviors of phase change materials in nanocapsule interface confinement conditions but also provide a good example to develop new types of heat energy storage composite materials.
Co-reporter:Shudong Zhang, Quanhong Tao, Zhenyang Wang and Zhongping Zhang
Journal of Materials Chemistry A 2012 vol. 22(Issue 38) pp:20166-20169
Publication Date(Web):22 Aug 2012
DOI:10.1039/C2JM33316C
Brick-and-mortar microstructures of graphene oxide–polyethylene glycol (PEG) composite papers were easily prepared with large area. The freezing point of the PEG intercalated into the shaped composite paper could be successively decreased down to room temperature, while the melting point was kept constant with that of bulk PEG, which means controlled heat release was thus achieved.
Co-reporter:Renyong Liu, Bianhua Liu, Guijian Guan, Changlong Jiang and Zhongping Zhang
Chemical Communications 2012 vol. 48(Issue 75) pp:9421-9423
Publication Date(Web):02 Aug 2012
DOI:10.1039/C2CC34115H
Novel SERS nanotags with highly uniform and reproducible signals have been developed by the layer-by-layer assembly and crosslinkage of small silver nanoparticles at the surface of silica particles, which opens an avenue to the quantitative and reliable SERS application in bioassays.
Co-reporter:Qingsong Mei, Changlong Jiang, Guijian Guan, Kui Zhang, Bianhua Liu, Renyong Liu and Zhongping Zhang
Chemical Communications 2012 vol. 48(Issue 60) pp:7468-7470
Publication Date(Web):08 Jun 2012
DOI:10.1039/C2CC31992F
A combinational logic gate based on fluorescent graphene oxide has been reported to discriminate Fe3+, Fe2+ and their mixture in living cells by fluorescence imaging.
Co-reporter:Bianhua Liu, Guangmei Han, Zhongping Zhang, Renyong Liu, Changlong Jiang, Suhua Wang, and Ming-Yong Han
Analytical Chemistry 2012 Volume 84(Issue 1) pp:255
Publication Date(Web):November 28, 2011
DOI:10.1021/ac202452t
Here, we report the shell thickness-dependent Raman enhancement of silver-coated gold nanoparticles (Au@Ag NPs) for the identification and detection of pesticide residues at various fruit peels. The Raman enhancement of Au@Ag NPs to a large family of sulfur-containing pesticides is ∼2 orders of magnitude stronger than those of bare Au and Ag NPs, and there is a strong dependence of the Raman enhancement on the Ag shell thickness. It has been shown for the first time that the huge Raman enhancement is contributed by individual Au@Ag NPs rather than aggregated Au@Ag NPs with “hot spots” among the neighboring NPs. Therefore, the Au@Ag NPs with excellent individual-particle enhancement can be exploited as stand-alone-particle Raman amplifiers for the surface identification and detection of pesticide residues at various peels of fruits, such as apple, grape, mango, pear, and peach. By casting the particle sensors onto fruit peels, several types of pesticide residues (e.g., thiocarbamate and organophosphorous compounds) have been reliably/rapidly detected, for example, 1.5 nanograms of thiram per square centimeter at apple peel under the current unoptimized condition. The surface-lifting spectroscopic technique offers great practical potentials for the on-site assessment and identification of pesticide residues in agricultural products.
Co-reporter:Guijian Guan, Liang Yang, Qingsong Mei, Kui Zhang, Zhongping Zhang, and Ming-Yong Han
Analytical Chemistry 2012 Volume 84(Issue 21) pp:9492
Publication Date(Web):October 2, 2012
DOI:10.1021/ac302341b
To achieve selectivity in direct chemiluminescence (CL) detection is very significant and a great challenge as well. Here, we report a novel concept of developing intrinsically selective CL switching at the surface of Fe3O4 nanoparticles for the sensitive detection and simultaneous determination of various pesticides. Fe3O4 nanoparticles have peroxidase-like catalytic activity and catalyze the decomposition of dissolved oxygen to generate superoxide anions, so that the CL intensity of luminol was amplified by at least 20 times. The CL signals can be quenched by the addition of ethanol because ethanol readily reacts with superoxide anions as a radical scavenger. However, the quenching effect can be inhibited through the specific binding of target molecules on Fe3O4 nanoparticles, leading to CL “turn-on” in the presence of ethanol. The novel CL “switching-on” concept demonstrated unique advantages in the detection of pesticide residues. Using the surface coordinative reactions, nonredox pesticide ethoprophos were sensitively detected with a detection limit of 0.1 nM and had a very wide detection range of 0.1 nM to 100 μM. More importantly, the selectivity of CL switching is tunable through the special surface modification of Fe3O4 nanoparticles, and these Fe3O4 nanoparticles with different surface groups can generate unique CL response pattern for the simultaneous determination of various pesticides. Meanwhile, the superparamagnetic properties of Fe3O4 nanoparticles provide a simple magnetic separation approach to attain interference-free measurement for real detection. The very facile and versatile strategy reported here should open a new window to exploration of selective CL molecular switching and application of magnetic nanoparticles for chemo/biodetection.
Co-reporter:Min Wang, Qingsong Mei, Kui Zhang and Zhongping Zhang
Analyst 2012 vol. 137(Issue 7) pp:1618-1623
Publication Date(Web):23 Jan 2012
DOI:10.1039/C2AN16302K
Here we report that the dual fluorescence emissions from protein–gold (Au) nanoclusters can greatly be modulated by metal ions and the resultant fluorescence ratiometric responses provide a novel sensory method for the identification of amino acids. The protein–gold (Au) nanoclusters were simply synthesized by the reduction of chloroauric acid with bovine serum albumin (BSA), which exhibit dual emissions: the blue at 425 nm from the oxides of BSA, and the red at 635 nm from Au nanoclusters. It has been demonstrated that different metal ions react with BSA–Au nanoclusters and thus greatly affect the two emissions in different ways by fluorescence enhancement or quenching. Interestingly, the addition of amino acids leads to fluorescence ratiometric changes through the interactions with the bound metal ions. When BSA–Au nanocluster probes modulated by four different metal ions were used together to construct a sensor array, different amino acids were clearly discriminated by the distinctive patterns of four ratiometric fluorescence responses. Results and methods reported here provide a unique strategy for the determination of amino acids.
Co-reporter:Jing Luo, Liying Zhang, Danjun Chen, Peng Wang, Jiawei Zhao, Yan Peng, Shuhu Du and Zhongping Zhang
Analyst 2012 vol. 137(Issue 12) pp:2891-2902
Publication Date(Web):02 Apr 2012
DOI:10.1039/C2AN35049A
This paper reports the preparation of puerarin (PR) imprinted layer-coated silica microparticles toward selective recognition of PR and fast affinity-enrichment of the main isoflavonoid glycosides from the crude extract of Radix puerariae. Before the preparation, quantum mechanics (QM) method was applied to identify three kinds of common functional monomers capable of interaction with PR and then predicted optimal functional monomer (acrylamide, AA) and the relative molar ratio of template to functional monomer (PR/AA, 1:4). The obtained PR-imprinted silica microparticles were evaluated by transmission electron microscope (TEM) and rebinding experiments, exhibiting good morphology and high binding affinity to PR. Meanwhile, the rebinding amount of the imprinted microparticles to PR was nearly 2.1-folds that of non-imprinted microparticles. When the PR-imprinted microspheres were used as packing materials for solid-phase extraction, the recovery yields of PR, daidzin (DD) and genistin (GS) were simultaneously up to 90% by one-step extraction from the crude extract of Radix puerariae. Additionally, the PR-imprinted microparticles could be re-used for at least 5 times without losing any extraction efficiency. These results indicate that the PR-imprinted microparticles have highly selective adsorption capabilities to PR, DD and GS from the crude extract of Radix puerariae. The method of molecularly imprinted polymers (MIPs) coupled with solid-phase extraction (SPE) provides a good solution of the enrichment and separation of active extracts from complicated traditional Chinese medicine (TCM) with certain structures.
Co-reporter:Ying Xie, Danjun Chen, Jiawei Zhao, Yan Peng, Nan Jiang, Xuemin Zhou, Shuhu Du and Zhongping Zhang
RSC Advances 2012 vol. 2(Issue 1) pp:273-283
Publication Date(Web):02 Nov 2011
DOI:10.1039/C1RA00438G
This work presents an approach called “hybrid design” which combines “grafting from” and “grafting through” methods, in order to prepare highly dense imprinted layer-coated silica particles for improved binding capacity to metsulfuron-methyl (MSM). The imprinted conditions including the kind of solvent and molar ratio of template to functional monomer were carefully optimized by quantum mechanics method. The obtained imprinted materials were evaluated by transmission electron microscopy and rebinding experiments, exhibiting well-controlled shell thickness (up to ∼30 nm) and high binding affinity to MSM. Moreover, the rebinding amount of MSM-imprinted particles to MSM was nearly 1.6- and 1.4-folds that of normal surface-imprinted particles, respectively. When the MSM-imprinted particles were used as dispersive solid-phase extraction materials, the recoveries (RSDs) of MSM determined by high-performance liquid chromatography (HPLC) were 93.4% (1.5%), 86.8% (3.2%) and 88.4% (2.7%) in the spiked water, soil and wheat samples, respectively. Therefore, the method will provide new opportunities for enrichment and detection of trace MSM from complicated matrices.
Co-reporter:Dr. Guijian Guan;Renyong Liu;Qingsong Mei ;Dr. Zhongping Zhang
Chemistry - A European Journal 2012 Volume 18( Issue 15) pp:4692-4698
Publication Date(Web):
DOI:10.1002/chem.201102576
Abstract
We have devised a facile and general methodology for the synthesis of various molecularly imprinted shells at the surface of polystyrene (PS) colloidal spheres to recognize the explosive compound 2,4,6-trinitrotoluene (TNT). PS spheres with surface-functionalized carboxyl-group layers could direct a selective imprinting polymerization on their surface through the hydrogen-bonding interactions between surface carboxyl groups and amino monomers. Meanwhile, homogeneous polymerization in the solution phase was completely prevented by stepwise polymerization. The overall process led to the formation of monodisperse molecularly imprinted core–shell microspheres, and was very successful in the preparation of organic polymer and inorganic xerogel shells. Furthermore, greater capacity and faster binding kinetics towards target species were achieved, because surface-imprinted sites ensured the complete removal of templates, good accessibility to target molecules, and low mass-transfer resistance. The results reported herein, concerning the production of high-quality molecularly imprinted products, could also form the basis for the formulation of a new strategy for the fabrication of various functional coating layers on colloidal spheres with potential applications in the fields of separations and chemical sensing.
Co-reporter:Liang Yang ; Guijian Guan ; Suhua Wang
The Journal of Physical Chemistry C 2012 Volume 116(Issue 5) pp:3356-3362
Publication Date(Web):January 6, 2012
DOI:10.1021/jp210316s
This paper reports a new nanosized anatase particle enhanced chemiluminescence sensor that utilizes the catalytic surface of anatase for sensitive detection of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). This chemiluminescence sensor was composed of anatase nanoparticles grafted with the nitrobenzoxadiazole (NBD) fluorophore, bis(2,4,6-trichlorophenyl)oxalate (TCPO), and hydrogen peroxide (H2O2). The chemiluminescence efficiency of the sensor has been greatly enhanced by 6 times compared with that in the absence of nano-anatase. However, 2,4-D could greatly suppress the chemiluminescence enhancement of anatase nanoparticles probably by adsorbing and competitively reacting with the activated hydrogen peroxide on the anatase surface. The phenomenon has been used to detect 2,4-D by monitoring the quenching of the chemiluminescence of the system. The limit of detection of the chemiluminescence sensor system was estimated to be as low as 0.33 nmol/L. The simple and sensitive sensor reported herein exhibited an effective combination of traditional chemiluminescence with nano-anatase for sensitive detection, thus promoting the advances of chemiluminescence sensing on the basis of nanomaterials.
Co-reporter:Lin Pan, Quanhong Tao, Shudong Zhang, Shuangshuang Wang, Jian Zhang, Suhua Wang, Zhenyang Wang, Zhongping Zhang
Solar Energy Materials and Solar Cells 2012 98() pp: 66-70
Publication Date(Web):
DOI:10.1016/j.solmat.2011.09.020
Co-reporter:Qingsong Mei;Dr. Zhongping Zhang
Angewandte Chemie International Edition 2012 Volume 51( Issue 23) pp:5602-5606
Publication Date(Web):
DOI:10.1002/anie.201201389
Co-reporter:Qingsong Mei;Dr. Zhongping Zhang
Angewandte Chemie 2012 Volume 124( Issue 23) pp:5700-5704
Publication Date(Web):
DOI:10.1002/ange.201201389
Co-reporter:Kui Zhang ; Haibo Zhou ; Qingsong Mei ; Suhua Wang ; Guijian Guan ; Renyong Liu ; Jian Zhang
Journal of the American Chemical Society 2011 Volume 133(Issue 22) pp:8424-8427
Publication Date(Web):May 12, 2011
DOI:10.1021/ja2015873
To detect trace trinitrotoluene (TNT) explosives deposited on various surfaces instantly and on-site still remains a challenge for homeland security needs against terrorism. This work demonstrates a new concept and its utility for visual detection of TNT particulates on various package materials. The concept takes advantages of the superior fluorescent properties of quantum dots (QDs) for visual signal output via ratiometric fluorescence, the feasibility of surface grafting of QDs for chemical recognition of TNT, and the ease of operation of the fingerprint lifting technique. Two differently sized CdTe QDs emitting red and green fluorescences, respectively, have been hybridized by embedding the red-emitting one in silica nanoparticles and covalently linking the green-emitting one to the silica surface, respectively, to form a dual-emissive fluorescent hybrid nanoparticle. The fluorescence of red QDs in the silica nanoparticles stays constant, whereas the green QDs functionalized with polyamine can selectively bind TNT by the formation of Meisenheimer complex, leading to the green fluorescence quenching due to resonance energy transfer. The variations of the two fluorescence intensity ratios display continuous color changes from yellow-green to red upon exposure to different amounts of TNT. By immobilization of the probes on a piece of filter paper, a fingerprint lifting technique has been innovated to visualize trace TNT particulates on various surfaces by the appearance of a different color against a yellow-green background under a UV lamp. This method shows high selectivity and sensitivity with a detection limit as low as 5 ng/mm2 on a manila envelope and the attribute of being seen with the naked eye.
Co-reporter:Haibo Zhou, Zhongping Zhang, Changlong Jiang, Guijian Guan, Kui Zhang, Qingsong Mei, Renyong Liu, and Suhua Wang
Analytical Chemistry 2011 Volume 83(Issue 18) pp:6913
Publication Date(Web):August 19, 2011
DOI:10.1021/ac201407z
The highest Raman enhancement factors are obtained in a double resonance: molecular electronic resonance and plasmon resonance with a “hot spot” in surface-enhanced Raman scattering (SERS). However, for most molecules of interest the double resonance is not realized with the excitation frequencies normally used in Raman. The latter may limit the practical applications of SERS for trace analysis. Here, we report that Raman-inactive trinitrotoluene (TNT) lights up the ultrahigh Raman scattering of off-resonated p-aminobenzenethiol (PABT) through the formation of charge-transfer TNT-PABT complex on the top-closed flexible silver nanotube array. Raman hot spots can spontaneously form in a reversible way by the self-approaching of flexible nanotubes driven through the capillary force of solvent evaporation. Meanwhile, the PABT-TNT-PABT bridges between self-approaching silver nanotubes possibly form by the specific complexing and zwitterion interactions, and the resultant chromophores can absorb the visible light that matches with the incident laser and the localized surface plasmon of a silver nanotube array. The multiple spectral resonances lead to the huge enhancement of Raman signals of PABT molecules due to the presence of ultratrace TNT. The enhancement effect is repeatedly renewable by the reconstruction of molecular bridges and can selectively detect TNT with a limit of 1.5 × 10–17 M. The results in this report provide the simple and supersensitive approach to the detection of TNT explosives and the possibility of building a robust Raman-based assay platform.
Co-reporter:Guijian Guan, Shuangshuang Wang, Haibo Zhou, Kui Zhang, Renyong Liu, Qingsong Mei, Suhua Wang, Zhongping Zhang
Analytica Chimica Acta 2011 Volume 702(Issue 2) pp:239-246
Publication Date(Web):30 September 2011
DOI:10.1016/j.aca.2011.06.047
Molecularly imprinted polypyrrole (PPy) nanonecklaces were facilely synthesized through a two-step oxidative polymerization route for the amperometric detection of non-electrochemically active herbicide. It has been demonstrated that dissolved oxygen can preoxidize pyrrole to form PPy oligomer bundles, which further self-assemble into necklace-like micelles in the presence of cetyltrimethylammonium bromide. Subsequently, these microstructures were immediately gelled through quick polymerization of residual pyrrole monomers, leading to the formation of PPy nanonecklaces. Meanwhile, herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) was synchronously imprinted into the formed PPy and highly dense imprinted sites were generated in PPy nanonecklaces because the necklace-like structure with microgaps/pores provides the facile and complete removal of templates. The imprinted nanonecklaces exhibit the high capacity and fast kinetics to uptake 2,4-D molecules, and produce a imprinting factor of ∼4.2. Importantly, the recognition and binding to 2,4-D significantly amplify the current response by a factor of 8 times in amperometric measurements, providing a sensitive detection of 2,4-D. The molecular imprinting strategy opens a novel avenue to the direct detection of non-electrochemically active species in a more convenient, simpler and cheaper way than the traditional competition-displacing approaches.Graphical abstractMolecular imprinting in polypyrrole (PPy) nanonecklaces have been achieved through the initial preoxidization of pyrrole by dissolved oxygen and subsequent quick polymerization by ammonium persulfate (APS), and the selective binding of imprinted sites to target species leads to the amplification of current response by a factor of 8 times toward the detection of trace herbicide.Highlights► Molecular imprinting in polypyrrole nanonecklaces can be facilely achieved through the initial preoxidization of pyrrole and subsequent quick polymerization. ► The resultant imprinted nanonecklaces exhibit the high capacity and fast kinetics to uptake herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). ► Importantly, the recognition and binding to 2,4-D significantly amplify the current response by a factor of 8 times in amperometric measurements, providing a sensitive detection of non-electrochemically active 2,4-D.
Co-reporter:Jing-Feng Zhao, Ji-Ming Song, Cheng-Cheng Liu, Bian-Hua Liu, He-Lin Niu, Chang-Jie Mao, Sheng-Yi Zhang, Yu-Hua Shen and Zhong-Ping Zhang
CrystEngComm 2011 vol. 13(Issue 19) pp:5681-5684
Publication Date(Web):05 Aug 2011
DOI:10.1039/C1CE05323J
Hexagonal Co0.85Se with Ni0.85Se-type structure has been successfully synthesized without any surfactants by a solvothermal reduction route. SEM observation indicated that the obtained Co0.85Se nanostructures were of graphene-like morphology with a thickness less than 10 nm. The influence of the reaction temperature and the molar ratios of reactants has been studied in detail, and the results reveal the two reaction conditions play a crucial role in determining the final morphologies of the samples. The as-prepared product is determined to be ferromagnetic at room temperature from magnetic measurements. And the product with high specific surface area could be used as an adsorbent in wastewater treatment, which may be very useful for the environment.
Co-reporter:Ping Liu, Renyong Liu, Guijian Guan, Changlong Jiang, Suhua Wang and Zhongping Zhang
Analyst 2011 vol. 136(Issue 20) pp:4152-4158
Publication Date(Web):19 Aug 2011
DOI:10.1039/C1AN15318H
A surface-enhanced Raman scattering (SERS)-based sensor for the determination of theophylline (THO) has been developed by imprinting the target molecules on the surface of silver nanoparticles. The desired recognition sites are generated after template removal and homogeneous distribution on the silver nanoparticles that have been incorporated within polymer matrix by the in situreduction of theophylline-silver complexes, providing molecular recognition ability and SERS active surfaces. The theophylline molecules, complementary to the shape, size, and functionality of the recognition cavities, can selectively bind to the recognition sites at the surface of silver nanoparticles driven by the formation of hydrogen bonding and surface coordination. It has been demonstrated that the SERS signals of the theophylline molecules captured on the surface of the silver nanoparticles have a good reproducibility and a dose–response relationship to the target analytes, showing the potential for reliable identification and quantification of the bioactive compound. The molecular imprinting-based SERS sensor, like antibodies or enzymes, also possesses the ability to distinguish theophylline from the closely related structure caffeine due to the variations of molecular size and shape as well as the different affinity to silver ions.
Co-reporter:Renyong Liu, Guijian Guan, Suhua Wang and Zhongping Zhang
Analyst 2011 vol. 136(Issue 1) pp:184-190
Publication Date(Web):01 Oct 2010
DOI:10.1039/C0AN00447B
To convert the binding events on molecularly imprinted polymers (MIPs) into physically detectable signals and to extract the templates completely are the great challenges in developing MIP-based sensors. In this paper, a core-shell nanostructure was employed in constructing the MIP chemosensor for the improvements of template extraction efficiency and imprinted sites accessibility. Vinyl-substituted zinc(II) protoporphyrin (ZnPP) was used as both fluorescent reporter and functional monomer to synthesize atrazine-imprinted polymer shell at silica nanoparticle cores. The template atrazine coordinates with the Lewis acid binding site Zn of ZnPP to form a complex for the molecular imprinting polymerization. These imprinted sites are located in polymer matrix of the thin shells (∼8 nm), possessing better accessibility and lower mass-transfer resistance for the target molecules. The fluorescence properties of ZnPP around the imprinted sites will vary upon rebinding of atrazine to these imprinted sites, realizing the conversion of rebinding events into detectable signals by monitoring fluorescence spectra. This MIP probe showed a limit of detection (LOD) of about 1.8 μM for atrazine detection. The core-shell nanostructured MIP method not only improves the sensitivity, but also shows high selectivity for atrazine detection when compared with the non-molecular imprinted counterparts.
Co-reporter:Bianhua Liu, Mingyong Han, Guijian Guan, Suhua Wang, Renyong Liu, and Zhongping Zhang
The Journal of Physical Chemistry C 2011 Volume 115(Issue 35) pp:17320-17327
Publication Date(Web):July 27, 2011
DOI:10.1021/jp205327q
Here, we report a general protocol for coating molecularly imprinted polymers (MIPs) at the superparamagnetic iron oxide nanoparticles (Fe3O4 NPs) to make highly controllable core–shell Fe3O4@MIP NPs for rapid enrichment and separation of herbicides in water. Acrylic acid monomers were first anchored at the surface of Fe3O4 by the simple complexing reaction with unsaturated iron ions at the nanoparticle surface, which forms a polymerizable molecule monolayer. It was found that the monolayer highly directed the selective occurrence of molecular imprinting polymerization at the surface of Fe3O4 NPs, and the homogeneous copolymerization in solution phase was completely prohibited by the optimized reaction conditions. As a result, one can easily produce the uniformly spherical Fe3O4@MIP NPs with tunable MIP shell thickness from several to tens of nanometers that can simply be achieved by changing the amounts of precursors. The Fe3O4@MIP NPs with saturation magnetization of 38 emu/g exhibit the capability of ultrafast enriching and separating herbicide 2,4-dichlorophenoxyacetic acid (∼2% in weight) and are renewable and cyclically exploited due to their monodispersive and superparamagnetic features. The method of molecular imprinting at superparamagnetic particles can be extended to a wide range of applications for pollutant water treatment, biological molecule purification, and drug separation.
Co-reporter:Jian Zhang;Dr. Shudong Zhang;Dr. Zhenyang Wang;Dr. Zhongping Zhang;Shuangshuang Wang;Dr. Suhua Wang
Angewandte Chemie 2011 Volume 123( Issue 27) pp:6168-6171
Publication Date(Web):
DOI:10.1002/ange.201101704
Co-reporter:Jian Zhang;Dr. Shudong Zhang;Dr. Zhenyang Wang;Dr. Zhongping Zhang;Shuangshuang Wang;Dr. Suhua Wang
Angewandte Chemie International Edition 2011 Volume 50( Issue 27) pp:6044-6047
Publication Date(Web):
DOI:10.1002/anie.201101704
Co-reporter:J. Zhang, S. S. Wang, S. D. Zhang, Q. H. Tao, L. Pan, Z. Y. Wang, and Z. P. Zhang , Y. Lei, S. K. Yang, and H. P. Zhao
The Journal of Physical Chemistry C 2011 Volume 115(Issue 41) pp:20061-20066
Publication Date(Web):September 1, 2011
DOI:10.1021/jp202373b
As one of the promising thermal energy storage materials, inorganic hydrate salts have long been suffering from two intrinsic drawbacks including phase segregation and supercooling in their heat storage applications. In this study, Na2SO4·10H2O@SiO2 solid nanobowls, structured as Na2SO4·10H2O nanoclusters dispersed in SiO2 matrix, were synthesized on a large scale through hydrolysis of tetraethyl silicate and 3-aminopropyltriethoxysilane synchronously in reverse-microemulsion. Microstress imbalance originated from the relative rotation of the growing nanoparticle inside the aqueous droplet leads to a whirlpool-like microreactor and thus results in the formation of brims of the solid nanobowls. Confined by SiO2 matrix, heat storage properties of the hydrate salts are greatly improved. Their phase segregation is inhibited, and their supercooling is mitigated as well, which might originate from the mesoporous confinement effect. Their excellent cycling performance is of great importance in the prospective thermal energy storage application.
Co-reporter:Qingsong Mei, Kui Zhang, Guijian Guan, Bianhua Liu, Suhua Wang and Zhongping Zhang
Chemical Communications 2010 vol. 46(Issue 39) pp:7319-7321
Publication Date(Web):07 Sep 2010
DOI:10.1039/C0CC02374D
A bright blue fluorescent graphene oxide that originates from passivation of surface reactive sites by amide formation and ring-opening amination of epoxide has been prepared. The surface polarity and charges of the fluorescent graphene oxide can synchronously be tuned by varying the used alkylamines.
Co-reporter:Kui Zhang, Qingsong Mei, Guijian Guan, Bianhua Liu, Suhua Wang, and Zhongping Zhang
Analytical Chemistry 2010 Volume 82(Issue 22) pp:9579
Publication Date(Web):October 25, 2010
DOI:10.1021/ac102531z
The development of a simple and on-site assay for the detection of organophosphorus pesticed residues is very important for food safety and exosystem protection. This paper reports the surface coordination-originated fluorescence resonance energy transfer (FRET) of CdTe quantum dots (QDs) and a simple ligand-replacement turn-on mechanism for the highly sensitive and selective detection of organophosphorothioate pesticides. It has been demonstrated that coordination of dithizone at the surface of CdTe QDs in basic media can strongly quench the green emission of CdTe QDs by a FRET mechanism. Upon the addition of organophosphorothioate pesticides, the dithizone ligands at the CdTe QD surface are replaced by the hydrolyzate of the organophosphorothioate, and hence the fluorescence is turned on. The fluorescence turn on is immediate, and the limit of detection for chlorpyrifos is as low as ∼0.1 nM. Two consecutive linear ranges allow a wide determination of chlorpyrifos concentrations from 0.1 nM to 10 μM. Importantly, the fluorescence turn-on chemosensor can directly detect chlorpyrifos residues in apples at a limit of 5.5 ppb, which is under the maximum residue limit allowed by the U.S. Environmental Protection Agency. The very simple strategy reported here should facilitate the development of fluorescence turn-on chemosensors for chemo/biodetection.
Co-reporter:Yan Peng, Ying Xie, Jing Luo, Li Nie, Yun Chen, Lina Chen, Shuhu Du, Zhongping Zhang
Analytica Chimica Acta 2010 Volume 674(Issue 2) pp:190-200
Publication Date(Web):3 August 2010
DOI:10.1016/j.aca.2010.06.022
This paper reports the preparation of metsulfuron-methyl (MSM) imprinted polymer layer-coated silica nanoparticles toward analysis of trace sulfonylurea herbicides in complicated matrices. To induce the selective occurrence of surface polymerization, the polymerizable double bonds were first grafted at the surface of silica nanoparticles by the silylation. Afterwards, the MSM templates were imprinted into the polymer-coating layer through the interaction with functional monomers. The programmed heating led to the formation of uniform MSM-imprinted polymer layer with controllable thickness, and further improved the reproducibility of rebinding capacity. After removal of templates, recognition sites of MSM were exposed in the polymer layers. As a result, the maximum rebinding capacity was achieved with the use of optimal grafting ratio. There was also evidence indicating that the MSM-imprinted polymer nanoparticles compared with nonimprinted polymer nanoparticles had a higher selectivity and affinity to four structure-like sulfonylurea herbicides. Moreover, using the imprinted particles as dispersive solid-phase extraction (DSPE) materials, the recoveries of four sulfonylurea herbicides determined by high-performance liquid chromatography (HPLC) were 80.2–99.5%, 83.8–102.4%, 77.8–93.3%, and 73.8–110.8% in the spiked soil, rice, soybean, and corn samples, respectively. These results show the possibility that the highly selective separation and enrichment of trace sulfonylurea herbicides from soil and crop samples can be achieved by the molecular imprinting modification at the surface of silica nanoparticles.
Co-reporter:Qing Lu, Xuemei Chen, Li Nie, Jing Luo, Huijun Jiang, Lina Chen, Qin Hu, Shuhu Du, Zhongping Zhang
Talanta 2010 Volume 81(Issue 3) pp:959-966
Publication Date(Web):15 May 2010
DOI:10.1016/j.talanta.2010.01.044
This paper reports the preparation of high density imprinted layer-coated silica nanoparticles toward selective recognition and fast enrichment of chlorpyrifos (CP) from complicated matrices. The molecularly imprinted polymers (MIPs) were successfully coated at the surface of modified silica through using the chemical immovable vinyl groups at the nanoparticles’ surface, followed by the graft copolymerization of methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) in the presence of templates CP. It has been demonstrated that the space of end vinyl groups at the surface of silica can be controlled by changing the condition of chemical modification, regulating the thickness of imprinted shells and the density of efficient imprinted sites. After removal of templates by solvent extraction, the recognition sites of CP were created in the polymer coating layer. The CP-imprinted nanoparticles exhibited high recognition selectivity and binding affinity to CP analyte. When the CP-imprinted nanoparticles were used as dispersive solid-phase extraction (dSPE) materials, the high recovery yields of 76.1–93.5% from various spiked samples with only 1 μg/mL analyte were achieved by one-step extraction. These results reported herein provide the possibility for the separation and enrichment of CP from complicated matrices by the molecular imprinting modification at the surface of common silica nanoparticles.
Co-reporter:Junlong Geng;Ping Liu;Bianhua Liu;Guijian Guan;Ming-Yong Han
Chemistry - A European Journal 2010 Volume 16( Issue 12) pp:3720-3727
Publication Date(Web):
DOI:10.1002/chem.200902721
Abstract
This paper reports a reversible dual fluorescence switch for the detection of a proton target and 2,4,6-trinitrotoluene (TNT) with opposite-response results, based on fluorophore derivatization of silica nanoparticles. Fluorescent silica nanoparticles were synthesized through modification of the surface with a nitrobenzoxadiazole (NBD) fluorophore and an organic amine to form a hybrid monolayer of fluorophores and amino ligands; the resultant nanoparticles showed different fluorescence responses to the proton target and TNT. Protonation of the amino ligands leads to fluorescence enhancement due to inhibition of photoinduced electron transfer (PET) between the amine and fluorophore. By contrast, addition of TNT results in fluorescence quenching because a fluorescence resonance energy transfer (FRET) happens between the NBD fluorophore and the formed TNT–amine complex. The fluorescence signal is reversible through washing with the proper solvents and the nanoparticles can be reused after centrifugal separation. Furthermore, these nanoparticles were assembled into chips on an etched silicon wafer for the detection of TNT and the proton target. The assembled chip can be used as a convenient indicator of herbicide (2,4-dichlorophenoxyacetic acid) and TNT residues with the use of only 10 μL of sample. The simple NBD-grafted silica nanoparticles reported here show a reversible signal and good assembly flexibility; thus, they can be applied in multianalyte detection.
Co-reporter:Guijian Guan, Renyong Liu, Minghong Wu, Zhen Li, Bianhua Liu, Zhenyang Wang, Daming Gao and Zhongping Zhang
Analyst 2009 vol. 134(Issue 9) pp:1880-1886
Publication Date(Web):10 Jul 2009
DOI:10.1039/B820962F
In this paper, we report a layer-by-layer (LbL) molecular imprinting strategy for constructing molecular recognition sites at the surface of colloidal silica particles by glutaraldehyde (GA)-mediated covalent assembly of gelatin protein in aqueous media. Accompanying the repeated coating of gelatin at the amine-capped silica particles, 2,4,6-trinitrotoluene (TNT) templates were synchronously imprinted into the formed gelatin shells by the charge-transfer interaction between the electron-deficient aromatic rings of TNT and the electron-rich amino groups of gelatin chains. The effective molecular recognition sites generated at the protein interlayers of gelatin shells of monodisperse silica@gelatin particles, and the rebinding TNT capacities changed nonlinearly with the layer number of imprinted gelatin. Three layers of imprinted gelatin produced the largest imprinting factor of ∼3.0, which is explained by the covalent assembly mechanism. The imprinting protocol is applicable to a broad range of biomaterials (such as proteins, enzymes, chitosan and biopolymers) for imprinting various molecules in aqueous media. Therefore, these results reported here will open a new window of interest in the exploration of novel molecular recognition systems for application in chemosensors, selective separation, and drug screening and release.
Co-reporter:Feng Wang, Wenbo Wang, Bianhua Liu, Zhenyang Wang, Zhongping Zhang
Talanta 2009 Volume 79(Issue 2) pp:376-382
Publication Date(Web):15 July 2009
DOI:10.1016/j.talanta.2009.03.062
Co-reporter:Qunling Fang;Junlong Geng;Bianhua Liu;Daming Gao Dr.;Fei Li;Zhenyang Wang Dr.;Guijian Guan Dr.
Chemistry - A European Journal 2009 Volume 15( Issue 43) pp:11507-11514
Publication Date(Web):
DOI:10.1002/chem.200901488
Abstract
This paper reports an inverted opal fluorescence chemosensor for the ultrasensitive detection of explosive nitroaromatic vapors through resonance-energy-transfer-amplified fluorescence quenching. The inverted opal silica film with amino ligands was first fabricated by the acid–base interaction between 3-aminopropyltriethoxysilane and surface sulfonic groups on polystyrene microsphere templates. The fluorescent dye was then chemically anchored onto the interconnected porous surface to form a hybrid monolayer of amino ligands and dye molecules. The amino ligands can efficiently capture vapor molecules of nitroaromatics such as 2,4,6-trinitrotoluene (TNT) through the charge-transfer complexing interaction between electron-rich amino ligands and electron-deficient aromatic rings. Meanwhile, the resultant TNT–amine complexes can strongly suppress the fluorescence emission of the chosen dye by the fluorescent resonance energy transfer (FRET) from the dye donor to the irradiative TNT–amino acceptor through intermolecular polar–polar resonance at spatial proximity. The quenching response of the highly ordered porous films with TNT is greatly amplified by at least 10-fold that of the amorphous silica films, due to the interconnected porous structure and large surface-to-volume ratio. The inverted opal film with a stable fluorescence brightness and strong analyte affinity has lead to an ultrasensitive detection of several ppb of TNT vapor in air.
Co-reporter:Qunling Fang;Junlong Geng;Bianhua Liu;Daming Gao Dr.;Fei Li;Zhenyang Wang Dr.;Guijian Guan Dr.
Chemistry - A European Journal 2009 Volume 15( Issue 43) pp:
Publication Date(Web):
DOI:10.1002/chem.200990169
Co-reporter:Daming Gao, Zhenyang Wang, Bianhua Liu, Lin Ni, Minghong Wu and Zhongping Zhang
Analytical Chemistry 2008 Volume 80(Issue 22) pp:8545
Publication Date(Web):October 11, 2008
DOI:10.1021/ac8014356
This paper reports a resonance energy transfer-amplifying fluorescence quenching at the surface of silica nanoparticles for the ultrasensitive detection of 2,4,6-trinitrotoluene (TNT) in solution and vapor environments. Fluorescence dye and organic amine were covalently modified onto the surface of silica nanoparticles to form a hybrid monolayer of dye fluorophores and amine ligands. The fluorescent silica particles can specifically bind TNT species by the charge-transfer complexing interaction between electron-rich amine ligands and electron-deficient aromatic rings. The resultant TNT−amine complexes bound at the silica surface can strongly suppress the fluorescence emission of the chosen dye by the fluorescence resonance energy transfer (FRET) from dye donor to the irradiative TNT−amine acceptor through intermolecular polar−polar interactions at spatial proximity. The quenching efficiency of the hybrid nanoparticles with TNT is greatly amplified by at least 10-fold that of the corresponding pure dye. The nanoparticle-assembled arrays on silicon wafer can sensitively detect down to ∼1 nM TNT with the use of only 10 μL of solution (∼2 pg TNT) and several ppb of TNT vapor in air. The simple FRET-based nanoparticle sensors reported here exhibit a high and stable fluorescence brightness, strong analyte affinity, and good assembly flexibility and can thus find many applications in the detection of ultratrace analytes.
Co-reporter:Xinran Liu ; Bianhua Liu ; Zhenyang Wang ; Buchang Zhang
The Journal of Physical Chemistry C 2008 Volume 112(Issue 26) pp:9632-9636
Publication Date(Web):June 6, 2008
DOI:10.1021/jp8017088
Highly oriented vaterite CaCO3 tablet-like arrays were formed at the air/water interface through the cooperative mineralization regulated by polypeptide and double hydrophilic block copolymer under ambient conditions. The nearly parallel arrangement of CaCO3 vaterite tablets at the air/water interface shows the remarkable resemblance to the morphology of nacreous layers. The poly(aspartic acid) (PASP) with high molecular weight (Mw = 11 000) and low solubility in water promoted the formation of vaterite tablets at the air/water interface, and stabilized the vaterite tablets by aggregation at the air/water interface and adsorption at the surface of vaterite tablets. Meanwhile, the highly hydrophilic poly(ethylene glycol)-block-poly(methacrylic acid) (PEG-b-PMAA) played an important role in regulating the arrangement and orientation of vaterite CaCO3 tablets, leading to the oriented tablet-like arrays at the air/water interface. Detailed experiments revealed that hydrophilic PEG-b-PMAA alone did not produce any form of CaCO3 crystals at the air/water interface, but could induce the formation of calcite CaCO3 particles in the water phase. However, high molecular weight PASP alone led to the formation of disk-like vaterite particles composed of helically aggregated nanoplates at the air/water interface, suggesting the regulating role of PEG-b-PMAA in the growth of vaterite tablet arrays. These results reported here provide a better understanding of the growth mechanism of nacreous layers and shells in nature.
Co-reporter:Z. Zhang;G. Guan;D. Gao;Z. Wang;B. Liu;C. Xie
Advanced Materials 2007 Volume 19(Issue 17) pp:2370-2374
Publication Date(Web):7 AUG 2007
DOI:10.1002/adma.200700984
Single-hole hollow polymer microspheres (see Figure) have been synthesized through the direct polymerization and cross-linking reactions occurring at the surface of carboxyl-capping polystyrene colloids, followed by removal of the core particles. The molecular imprinting of these single-hole hollow microspheres towards the specific high-capacity uptake of target species opens new routes to promising applications.
Co-reporter:Jian Zhang, Jianping Wang, Liang Yang, Bianhua Liu, Guijian Guan, Changlong Jiang and Zhongping Zhang
Chemical Communications 2014 - vol. 50(Issue 100) pp:NaN15873-15873
Publication Date(Web):2014/10/16
DOI:10.1039/C4CC07430K
A facile ligand replacement induced chemiluminescence method is developed for selective detection of the organophosphorus pesticide parathion-methyl based on the use of bifunctional Au–Fe3O4 dumbbell-like nanoparticles to overcome the interference from coexisting substances in a real sample.
Co-reporter:Qingsong Mei, Changlong Jiang, Guijian Guan, Kui Zhang, Bianhua Liu, Renyong Liu and Zhongping Zhang
Chemical Communications 2012 - vol. 48(Issue 60) pp:NaN7470-7470
Publication Date(Web):2012/06/08
DOI:10.1039/C2CC31992F
A combinational logic gate based on fluorescent graphene oxide has been reported to discriminate Fe3+, Fe2+ and their mixture in living cells by fluorescence imaging.
Co-reporter:Renyong Liu, Bianhua Liu, Guijian Guan, Changlong Jiang and Zhongping Zhang
Chemical Communications 2012 - vol. 48(Issue 75) pp:NaN9423-9423
Publication Date(Web):2012/08/02
DOI:10.1039/C2CC34115H
Novel SERS nanotags with highly uniform and reproducible signals have been developed by the layer-by-layer assembly and crosslinkage of small silver nanoparticles at the surface of silica particles, which opens an avenue to the quantitative and reliable SERS application in bioassays.
Co-reporter:Shudong Zhang, Quanhong Tao, Zhenyang Wang and Zhongping Zhang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 38) pp:NaN20169-20169
Publication Date(Web):2012/08/22
DOI:10.1039/C2JM33316C
Brick-and-mortar microstructures of graphene oxide–polyethylene glycol (PEG) composite papers were easily prepared with large area. The freezing point of the PEG intercalated into the shaped composite paper could be successively decreased down to room temperature, while the melting point was kept constant with that of bulk PEG, which means controlled heat release was thus achieved.
Co-reporter:Yingchang Jiang, Shudong Zhang, Qi Ji, Jian Zhang, Zhongping Zhang and Zhenyang Wang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 13) pp:NaN4579-4579
Publication Date(Web):2014/01/07
DOI:10.1039/C3TA14838F
Ultrathin two-dimensional (2D) nanosheets are a conceptually new category of nanoscale materials. Integration/assembly of individual 2D nanosheets into 3D hierarchical structures is an enormous challenge and an essential requirement for their application. Here we first report the direct synthesis of Cu7S4 hierarchical hollow cubic cages assembled by ultrathin nanosheets based on the Kirkendall effect. Slowly released Cu+ from Cu2O cubic template-crystals and S2− from decomposed thioacetamide (TAA) can react with each other and form a diffusion pair, which provides a thermodynamic and kinetic equilibrium to be responsible for the formation of ultrathin Cu7S4 nanosheets and the Cu7S4 hierarchical hollow cubic cages. Using this unique hollow structure and the outstanding catalytic property of the Cu7S4 nanosheets, as an example, we successfully demonstrate that Cu7S4 nanocages can effectively catalyse the “clock reaction”, which is a periodic cycle redox oscillation reaction between methylene blue (MB) and colorless leucomethylene blue (LMB). The unique hierarchical structure has been found to enhance the rate of this redox reaction via the ultrathin nanocatalyst. This work develops a facile strategy for synthesizing 3D hierarchical structures constructed by ultrathin nanosheets and demonstrates their superior ability to optimize the nanosheet-catalyzed clock reaction.
Co-reporter:Qingsong Mei, Kui Zhang, Guijian Guan, Bianhua Liu, Suhua Wang and Zhongping Zhang
Chemical Communications 2010 - vol. 46(Issue 39) pp:NaN7321-7321
Publication Date(Web):2010/09/07
DOI:10.1039/C0CC02374D
A bright blue fluorescent graphene oxide that originates from passivation of surface reactive sites by amide formation and ring-opening amination of epoxide has been prepared. The surface polarity and charges of the fluorescent graphene oxide can synchronously be tuned by varying the used alkylamines.
Co-reporter:Changlong Jiang, Renyong Liu, Guangmei Han and Zhongping Zhang
Chemical Communications 2013 - vol. 49(Issue 59) pp:NaN6649-6649
Publication Date(Web):2013/06/04
DOI:10.1039/C3CC43410A
A chemically reactive Raman probe has been developed for ultrasensitively monitoring and imaging the in vivo generation of femtomolar oxidative species as induced by anti-tumor drugs in living cells.
![3',6'-Dihydroxy-3H-spiro[isobenzofuran-1,9'-xanthen]-3-one](http://img.cochemist.com/ccimg/2400/2321-07-5.png)
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