12 results on '"Zhang, Zhongping"'
Search Results
2. Dynamic mapping of spontaneously produced H2S in the entire cell space and in live animals using a rationally designed molecular switch.
- Author
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Yang, Linlin, Zhao, Jun, Yu, Xinling, Zhang, Ruilong, Han, Guangmei, Liu, Renyong, Liu, Zhengjie, Zhao, Tingting, Han, Ming-Yong, and Zhang, Zhongping
- Subjects
MOLECULAR switches ,HYDROGEN sulfide ,NONCARBOXYLIC acids - Abstract
Hydrogen sulfide (H
2 S) is a key signaling molecule in the cytoprotection, vascular mediation and neurotransmission of living organisms. In-depth understanding of its production, trafficking, and transformation in cells is very important in the way H2 S mediates cellular signal transductions and organism functions; it also motivates the development of H2 S probes and imaging technologies. A fundamental challenge, however, is how to engineer probes with sensitivity and cellular penetrability that allow detection of spontaneous production of H2 S in the entire cell space and live animals. Here, we report a rationally designed molecular switch capable of accessing all intracellular compartments, including the nucleus, lysosomes and mitochondria, for H2 S detection. Our probe comprised three functional domains (H2 S sensing, fluorescence, and biomembrane penetration), could enter almost all cell types readily, and exhibit a rapid and ultrasensitive response to H2 S (≤120-fold fluorescence enhancement) for the dynamic mapping of spontaneously produced H2 S as well as its distribution in the whole cell. In particular, the probe traversed blood/tissue/cell barriers to achieve mapping of endogenous H2 S in metabolic organs of a live Danio rerio (zebrafish). These results open-up exciting opportunities to investigate H2 S physiology and H2 S-related diseases. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
3. Visualization of exhaled hydrogen sulphide on test paper with an ultrasensitive and time-gated luminescent probe.
- Author
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Zhang, Ruilong, Liu, Shijiang, Wang, Jianping, Han, Guangmei, Yang, Linlin, Liu, Bianhua, Guan, Guijian, and Zhang, Zhongping
- Subjects
CHEMORECEPTORS ,HYDROGEN sulfide ,AQUEOUS solutions ,PUBLIC health ,LUMINESCENT probes - Abstract
Luminescent chemosensors for hydrogen sulphide (H
2 S) are of great interest because of the close association of H2 S with our health. However, current probes for H2 S 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 H2 S, and its application in test paper for visualization of exhaled H2 S. 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 H2 S 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 H2 S, 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 H2 S gas exhaled by mice. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
4. Upconversion nanoparticles for ratiometric fluorescence detection of nitrite.
- Author
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Han, Junfen, Zhang, Cheng, Liu, Fei, Liu, Bianhua, Han, Mingyong, Zou, Wensheng, Yang, Liang, and Zhang, Zhongping
- Subjects
FLUORESCENCE ,NANOPARTICLES ,NITRITES ,DETECTORS ,IONS - Abstract
We have developed a selective upconversion switching method for the ratiometric fluorescence detection of nitrite using upconversion nanoparticles (UCNPs) and an efficient nitrite reaction. The green emission (λ
em = 539 nm) of NaYF4 :Yb3+ ,Er3+ nanoparticles can be selectively quenched by the neutral red (NR) dye due to the spectral overlap between the emission at 539 nm and the absorption of NR, while its red emission (λem = 654 nm) remains unchanged. Nitrite reacts specifically and strongly with NR to form diazonium salt and lose the diazonium group, which sharply decreases the absorption of NR. Thus, the green emission of NaYF4 :Yb3+ ,Er3+ can be recovered by increasing the amount of nitrite, leading to visible color changes from red to orange-yellow and finally green under excitation at 980 nm. The increase in the ratio of emission intensities (I539 /I654 ) is quantitatively correlated to the concentration of nitrite ions. Moreover, the developed method has been successfully applied to nitrite detection in real samples such as drinking water, natural water and meat foods. In particular, the upconversion sensors can efficiently avoid background optical interference and thus show potential for the detection of nitrite salts in complex samples. [ABSTRACT FROM AUTHOR]- Published
- 2014
- Full Text
- View/download PDF
5. Selective visual detection of trace trinitrotoluene residues based on dual-color fluorescence of graphene oxide–nanocrystals hybrid probe.
- Author
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Zhang, Kui, Yang, Lei, Zhu, Houjuan, Ma, Fang, Zhang, Zhongping, and Wang, Suhua
- Subjects
TNT (Chemical) ,FLUORESCENCE ,GRAPHENE oxide ,NANOCRYSTALS ,MOLECULAR probes - Abstract
Herein, for the detection of highly explosive 2,4,6-trinitrotoluene (TNT) instantly and on-site, a fluorescence ratiometric probe using a dual-emission nanohybrid has been developed. The nanohybrid comprises blue-colored fluorescent graphene oxide (FGO) being conjugated with red-emitting manganese-doped ZnS nanocrystals (ZnS:Mn NCs), the latter being functionalized with hexamethylenediamine. The blue fluorescence of FGO is insensitive to TNT and is used as an internal reference, whereas the red fluorescence of ZnS:Mn NCs can be selectively quenched by TNT through electron transfer, resulting in a unique red–purple–blue color response as the amount of TNT is increased. Thus, the probe could be used for the quantitative measurement of TNT based on the fluorescence ratiometric method. We demonstrated that the nanohybrid probe exhibited high visual detection sensitivity and reliability in comparison with single-color fluorescence quenching probes. A fluorescence test paper was prepared using the nanohybrid probe and was demonstrated to detect TNT residues directly on various surfaces including rubber, a person's fingers and manila envelopes with a visual detection limit as low as 5.68 ng mm
−2 , showing its promising application for security screening. [ABSTRACT FROM AUTHOR]- Published
- 2014
- Full Text
- View/download PDF
6. Dynamic mapping of spontaneously produced H 2 S in the entire cell space and in live animals using a rationally designed molecular switch.
- Author
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Yang L, Zhao J, Yu X, Zhang R, Han G, Liu R, Liu Z, Zhao T, Han MY, and Zhang Z
- Subjects
- Animals, Cell Line, Cell Nucleus chemistry, Fluorescence, Humans, Lysosomes chemistry, Mitochondria chemistry, Zebrafish, Fluorescent Dyes, Hydrogen Sulfide analysis
- Abstract
Hydrogen sulfide (H2S) is a key signaling molecule in the cytoprotection, vascular mediation and neurotransmission of living organisms. In-depth understanding of its production, trafficking, and transformation in cells is very important in the way H2S mediates cellular signal transductions and organism functions; it also motivates the development of H2S probes and imaging technologies. A fundamental challenge, however, is how to engineer probes with sensitivity and cellular penetrability that allow detection of spontaneous production of H2S in the entire cell space and live animals. Here, we report a rationally designed molecular switch capable of accessing all intracellular compartments, including the nucleus, lysosomes and mitochondria, for H2S detection. Our probe comprised three functional domains (H2S sensing, fluorescence, and biomembrane penetration), could enter almost all cell types readily, and exhibit a rapid and ultrasensitive response to H2S (≤120-fold fluorescence enhancement) for the dynamic mapping of spontaneously produced H2S as well as its distribution in the whole cell. In particular, the probe traversed blood/tissue/cell barriers to achieve mapping of endogenous H2S in metabolic organs of a live Danio rerio (zebrafish). These results open-up exciting opportunities to investigate H2S physiology and H2S-related diseases.
- Published
- 2018
- Full Text
- View/download PDF
7. Molecularly imprinted layer-coated monodisperse spherical silica microparticles toward affinity-enrichment of isoflavonoid glycosides from Radix puerariae.
- Author
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Luo J, Zhang L, Chen D, Wang P, Zhao J, Peng Y, Du S, and Zhang Z
- Subjects
- Acrylamide chemistry, Glycosides analysis, Glycosides isolation & purification, Methacrylates chemistry, Models, Molecular, Molecular Conformation, Particle Size, Silanes chemistry, Solid Phase Extraction, Solvents chemistry, Surface Properties, Glycosides chemistry, Isoflavones chemical synthesis, Isoflavones chemistry, Microspheres, Molecular Imprinting, Pueraria chemistry, Silicon Dioxide chemistry
- Abstract
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.
- Published
- 2012
- Full Text
- View/download PDF
8. Protein-gold nanoclusters for identification of amino acids by metal ions modulated ratiometric fluorescence.
- Author
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Wang M, Mei Q, Zhang K, and Zhang Z
- Subjects
- Amino Acids chemistry, Animals, Cattle, Fluorescence, Fluorescent Dyes chemistry, Serum Albumin, Bovine chemistry, Amino Acids analysis, Chemistry Techniques, Analytical, Gold chemistry, Metal Nanoparticles chemistry
- Abstract
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.
- Published
- 2012
- Full Text
- View/download PDF
9. Surface-enhanced Raman scattering sensor for theophylline determination by molecular imprinting on silver nanoparticles.
- Author
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Liu P, Liu R, Guan G, Jiang C, Wang S, and Zhang Z
- Subjects
- Beverages analysis, Kinetics, Polymers chemistry, Metal Nanoparticles chemistry, Molecular Imprinting, Silver chemistry, Spectrum Analysis, Raman, Theophylline analysis
- Abstract
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 situ reduction 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.
- Published
- 2011
- Full Text
- View/download PDF
10. Core-shell nanostructured molecular imprinting fluorescent chemosensor for selective detection of atrazine herbicide.
- Author
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Liu R, Guan G, Wang S, and Zhang Z
- Subjects
- Nanoparticles ultrastructure, Polymers chemistry, Protoporphyrins chemistry, Silicon Dioxide chemistry, Spectrometry, Fluorescence, Atrazine analysis, Herbicides analysis, Molecular Imprinting methods, Nanoparticles chemistry
- Abstract
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.
- Published
- 2011
- Full Text
- View/download PDF
11. A simple, reliable and sensitive colorimetric visualization of melamine in milk by unmodified gold nanoparticles.
- Author
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Chi H, Liu B, Guan G, Zhang Z, and Han MY
- Subjects
- Animals, Cattle, Citric Acid chemistry, Spectrophotometry, Ultraviolet, Sulfates chemistry, Colorimetry methods, Gold chemistry, Metal Nanoparticles chemistry, Milk chemistry, Triazines analysis
- Abstract
In this paper, we report a simple, reliable and sensitive colourimetric visualization of melamine in milk products using citrate-stabilized gold nanoparticles (Au NPs). Upon exposure to ppb-level melamine, gold nanoparticle solution exhibits a highly sensitive colour change from red to blue and rapid aggregation kinetics within the initial 5 min, which can directly be seen with the naked eye and monitored by UV-vis absorbance spectra. As confirmed by the comparison with six other typical amino compounds, the melamine molecule itself contains multiple strong-binding sites to the surface of Au NPs and thus plays a role of molecular linker to efficiently crosslink Au NPs. Further evidence is that the sensitivity is significantly improved when NaHSO(4) is added to promote the ligand exchange between citrate and melamine at the surface of Au NPs. The NaHSO(4)-optimized Au NPs system provides a rapid colourimetric assay for the rapid detection of melamine down to approximately 25 ppb in real milk products.
- Published
- 2010
- Full Text
- View/download PDF
12. Protein-building molecular recognition sites by layer-by-layer molecular imprinting on colloidal particles.
- Author
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Guan G, Liu R, Wu M, Li Z, Liu B, Wang Z, Gao D, and Zhang Z
- Subjects
- Biocompatible Materials chemistry, Dinitrobenzenes chemistry, Gelatin chemistry, Microscopy, Electron, Scanning, Microscopy, Electron, Transmission, Nanotechnology methods, Nitro Compounds chemistry, Nitrobenzenes chemistry, Picrates chemistry, Silicon Dioxide chemistry, Surface Properties, Triazines chemistry, Trinitrotoluene chemistry, Molecular Imprinting methods, Proteins chemistry
- Abstract
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 approximately 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.
- Published
- 2009
- Full Text
- View/download PDF
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