Co-reporter:Tingting Xia, Qiang Ma, Tianyu Hu, Xingguang Su
Talanta 2017 Volume 170(Volume 170) pp:
Publication Date(Web):1 August 2017
DOI:10.1016/j.talanta.2017.03.081
•A nanohybrid is developed for trypsin detection.•PDA film has multiple advantages.In this work, we have designed a novel kind of nanohybrid with magnetic and photoluminescence (PL) property for trypsin detection. The modified magnetic Fe3O4 nanoparticles (MNPs) with polydopamine (PDA) and human serum albumin (HSA) were prepared through a one step self-polymerization under mild condition. The polydopamine (PDA) coating on MNPs can improve the biocompatibility of the MNP-PDA-HAS composite due to its hydrophilicity and multifunctional groups. When MNP-PDA-HSA composite was added into the Anti-HSA modified CdTe QDs (anti-HSA-QDs), HSA on the MNP-PDA-HSA composite was captured by the site of anti-HSA-QDs to form MNP-PDA-HSA/anti-HSA-QDs nanohybrid. Therefore, the photoluminescence of QDs can be quenched by Fe3O4 nanoparticles due to the electron transfer. In the presence of trypsin, the protein (anti-HSA) was digested by trypsin and QDs was separated from the nanohybrid surface. As a result, the photoluminescence intensity of QDs was recovered. The magnetic/luminescent bifunctional nanohybrid displayed excellent analytical performance for the detection of trypsin in the range of 0.5–30 μg/mL with a low detection limit of 0.25 μg/mL.A novel kind of nanohybrid with magnetic and photoluminescence (PL) property is developed for trypsin detectionDownload high-res image (145KB)Download full-size image
Co-reporter:Tingting Xia, Qiang Ma, Yang Li, Xu Yan and Xingguang Su
New Journal of Chemistry 2016 vol. 40(Issue 8) pp:6860-6866
Publication Date(Web):06 Jun 2016
DOI:10.1039/C6NJ00398B
In this work, we designed a novel ratiometric dual-emission fluorescence magnetic nanohybrid. Carbon-coated magnetic composite nanoparticles (Fe3O4@C NPs) were prepared through the poly-condensation reaction of glucose under hydrothermal conditions. With appropriate hydrothermal time, temperature and glucose concentration, the glucose was polymerized and carbonized. Then, carbon dots were in situ-synthesized in the carbon shell that gave blue fluorescence due to surface energy trap emission. Furthermore, the surface of Fe3O4@C NPs was endowed with positive charges through modification with poly(diallyldimethylammonium chloride) (PDDA), and the electrostatic forces could bind electronegative CdTe quantum dots (QDs) on the Fe3O4@C NP surface (Fe3O4@C@QDs). The carbon shell preserves the stability of internal Fe3O4 NPs and inhibits the quenching of CdTe QD photoluminescence. To further demonstrate the performance of the nanohybrid as an immunosensor, HIgG was employed as a model target. In a competitive immunoassay, Fe3O4@C@QDs were coated with anti-human IgG. After binding HIgG, HIgG–Au NPs were captured by the remaining unreacted site of anti-human IgG on the Fe3O4@C@QDs nanohybrid surface and quenched the fluorescence of CdTe QDs via fluorescence resonance energy transfer (FRET). The proposed ratiometric dual-emission (carbon dots and QDs) fluorescence magnetic nanohybrid displayed excellent analytical performance for the detection of HIgG in the range of 0.005–100 ng mL−1 with a lower detection limit of 0.0025 ng mL−1.
Co-reporter:Xin Zou, Hui Huang, Yuan Gao and Xingguang Su
Analyst 2012 vol. 137(Issue 3) pp:648-653
Publication Date(Web):05 Dec 2011
DOI:10.1039/C1AN16041A
A highly sensitive method for the detection of avian influenza virus (AIV) antigen by the resonance light scattering (RLS) technique has been developed in this paper. Magnetic silica nanoparticles (MNs) were modified with AIV antibodyvia covalent binding firstly, the MNs/AIV antibody–AIV antigen immunocomplex was formed after the addition of AIV antigen, which can increase the RLS signal at 545 nm. Under the optimized conditions, the enhanced intensities of RLS at 545 nm (ΔIRLS) were proportional to the concentrations of AIV antigen in the range of 0.5–50 ng mL−1, with a detection limit of 0.15 ng mL−1 and correlation coefficient of 0.995. This method was applied to the analysis of AIV antigen in spiked chicken serum samples and saliva samples with satisfactory results.
Co-reporter:Fengping Yang, Qiang Ma, Wei Yu, Xingguang Su
Talanta 2011 Volume 84(Issue 2) pp:411-415
Publication Date(Web):15 April 2011
DOI:10.1016/j.talanta.2011.01.054
A novel direct quantificational method through naked-eye colorimetric analysis of Hg2+ was constructed based on different degree of the fluorescence quenching of bi-color quantum dots (QDs) multilayer films (2-QDMF). The functional multilayer films were assembled by layer-by-layer (LBL) deposition of oppositely charged CdTe QDs and poly(dimethyldiallylemmonium chloride) (PDDA). Then the outermost layer of 2-QDMF was cross-linked to bovine serum albumin (BSA), polyethylene glycol (PEG) or glutathione (GSH). It was found that when BSA modified quartz slides were immersed into solutions containing Hg2+ and Cu2+ respectively, the 2-QDMF can be quenched by Hg2+, but not by Cu2+. Under the optimization conditions, the quenched photoluminescence (PL) intensities of multilayer films were almost linearly proportional to the concentration of Hg2+ in the range of 1.0 × 10−8 to 1.0 × 10−6 mol L−1 and the detection limit was 4.5 × 10−9 mol L−1. The proposed method is intuitional and convenient, which can be applied to the determination of trace Hg2+ in the artificial water sample with satisfactory results.
Co-reporter:Qiang Ma;Wei Yu;Hui Huang
Journal of Fluorescence 2011 Volume 21( Issue 1) pp:125-131
Publication Date(Web):2011 January
DOI:10.1007/s10895-010-0696-z
In this paper, we attempted to develop a novel application of Mn-doped ZnSe quantum dots (Mn: ZnSe d-dots) as probes to detect L-tyrosine (L-Tyr). The bio-conjugates of horseradish peroxidase (HRP)-conjugated Mn: ZnSe d-dots were used in the enzyme catalyzed reaction of L-Tyr with H2O2. Compared with traditional CdTe QDs, Mn: ZnSe d-dots have better biocompatibility and less negative impact on enzyme catalyzed system. In HRP-conjugated Mn: ZnSe-L-Tyr-H2O2 system, electron transfer occurred between Mn: ZnSe d-dots and HRP. It resulted in the luminescence quenching of the Mn: ZnSe d-dots., which can be used to detect L-Tyr. The coupling of efficient quenching of Mn: ZnSe d-dots photoluminescence (PL) and the effective enzyme-catalysis can afford a simple and sensitive method for L-Tyr detection. The Mn: ZnSe d-dots-enzyme catalyzed system displays great potential in the development of enzyme-based biosensing systems for various analytes.
Co-reporter:Chao Wang;Xue Gao
Analytical and Bioanalytical Chemistry 2010 Volume 397( Issue 4) pp:1397-1415
Publication Date(Web):2010 June
DOI:10.1007/s00216-010-3481-6
Quantum dots (QDs), also named semiconductor nanocrystals, have initiated a new realm of bioscience by combining nanomaterials with biology, which will profoundly influence future biological and biomedical research. In this review, we describe the extraordinary optical properties of QDs and developments in methods for their synthesis. We focus on fluorescent imaging with QDs both in vitro and in vivo, and the cytotoxicity of QDs and potential barriers to their use in practical biomedical applications. Finally, we provide insights into improvements aimed at decreasing the cytotoxicity of QDs and the future outlook of QD applications in biomedical fields.
Co-reporter:Qiang Ma, Wei Yu, Xingguang Su
Talanta 2010 Volume 82(Issue 1) pp:51-55
Publication Date(Web):30 June 2010
DOI:10.1016/j.talanta.2010.03.056
A sensitive QDs-based RLS assay method for the detection of Newcastle disease virus (NDV) antibody has been developed. CdTe quantum dots (QDs) were conjugated with Newcastle disease virus and used as RLS-based probes to detect NDV antibody. The electrostatic interaction between CdTe QDs and NDV resulted in enhanced resonance light scattering (RLS) signal characterized at 555 nm. Upon the addition of NDV antibody, QDs–NDV formed dispersive immunocomplex that can decrease the RLS signal. The decreased RLS intensity at 555 nm (ΔIRLS) was linearly proportional to the concentration of NDV antibody (Canti-NDV) in the range of 0.5–50 ng/mL, with correlation coefficient of 0.974 and detection limit of 0.1 ng/mL under the optimization conditions. The proposed method was applied to the determination of NDV antibody in spiked samples with satisfactory results.
Co-reporter:Chao Wang, Xue Gao, Qiang Ma and Xingguang Su
Journal of Materials Chemistry A 2009 vol. 19(Issue 38) pp:7016-7022
Publication Date(Web):07 Aug 2009
DOI:10.1039/B909546B
In this paper, Mn2+-doped ZnSe quantum dots (Mn:ZnSe d-dots) are synthesized successfully by a nucleation–doping method in aqueous solution with mercaptopropionic acid as the stabilizer. The optimal precursor ratio and kind of stabilizer for obtaining Mn:ZnSe d-dots with good photoluminescence emission properties was studied in detail. Finally, the photostability of the resulting Mn:ZnSe d-dots was studied and the results showed that Mn:ZnSe d-dots are much more photostable than CdTe quantum dots synthesized in aqueous solution, indicating their potential as a new generation of fluorescent labels for biological assays, imaging of cells and tissues, even in vivo investigations.
Co-reporter:Wenchao Dou
Luminescence 2009 Volume 24( Issue 1) pp:45-49
Publication Date(Web):
DOI:10.1002/bio.1062
Abstract
In this work, we studied the fluorescence quenching of the anionic conjugated polyelectrolyte PPE–SO3 by the paramagnetic species 2,2,6,6-tetramethylpiperidine-N-oxide free radical (TEMPO) in aqueous solution. At low quencher concentration the Stern–Volmer constant is 94 mol/L; as the quencher concentration increases the Stern–Volmer plots become superlinear. Ascorbic acid is used to reduce TEMPO to the corresponding hydroxylamine and the PPE–SO3 fluorescence is fully recovered. Under a large excess of ascorbic acid over TEMPO, the rise of fluorescence followed pseudo-first-order kinetics. The second-order rate constant calculated from this time course is 0.7 mol/L/s. Copyright © 2008 John Wiley & Sons, Ltd.
Co-reporter:Guannan Wang;Chao Wang;Wenchao Dou;Qiang Ma;Pingfan Yuan
Journal of Fluorescence 2009 Volume 19( Issue 6) pp:
Publication Date(Web):2009 November
DOI:10.1007/s10895-009-0493-8
In this paper, a simple synthesis method of small-size( about 50 nm in diameter), high magnetic and fluorescent bi-functional silica composite nanoparticles were developed, in which water-soluble Fe3O4 magnetic nanoparticlels (MNs) and CdTe quantum dots (QDs) were directly incorporated into a silica shell by reverse microemulsion method. The high luminescent QDs can be used as luminescent marker, while the high magnetic MNs allow the manipulation of the bi-functional silica composite nanoparticles by external magnetic field. Poly (dimethyldiallyl ammonium chloride) was used to balance the electrostatic repulsion between CdTe QDs and silica intermediates to enhance the fluorescence intensity of MNs-QDs/SiO2 composite nanoparticles. The optical property, magnetic property, size characterization of the bi-functional composite nanoparticles were studied by UV-Vis and PL emission spectra, VSM, TEM, SEM. The stabilities toward time, pH and ionic strength and the effect of MNs on the fluorescence properties of bi-functional silica composite nanoparticles were also studied in detail. By modifying the surface of MNs-QDs/SiO2 composite nanoparticles with amino and methylphosphonate groups, biologically functionalized and monodisperse MNs-QDs/SiO2composite nanoparticles can be obtained. In this work, bi-functional composite nanoparticles were conjugated with FITC labeled goat anti-rabbit IgG, to generate novel fluorescent-magnetic-biotargeting tri-functional composite nanoparticles, which can be used in a number of biomedical application.
Co-reporter:Chao Wang, Qiang Ma, Wenchao Dou, Shamsa Kanwal, Guannan Wang, Pingfan Yuan, Xingguang Su
Talanta 2009 Volume 77(Issue 4) pp:1358-1364
Publication Date(Web):15 February 2009
DOI:10.1016/j.talanta.2008.09.018
This paper presents the synthesis of aqueous CdTe QDs embedded silica nanoparticles by reverse microemulsion method and their applications as fluorescence probes in bioassay and cell imaging. With the aim of embedding more CdTe QDs in silica spheres, we use poly(dimethyldiallyl ammonium chloride) to balance the electrostatic repulsion between CdTe QDs and silica intermediates. By modifying the surface of CdTe/SiO2 composite nanoparticles with amino and methylphosphonate groups, biologically functionalized and monodisperse CdTe/SiO2 composite nanoparticles can be obtained. In this work, CdTe/SiO2 composite nanoparticles are conjugated with biotin-labeled mouse IgG via covalent binding. The biotin-labeled mouse IgG on the CdTe/SiO2 composite nanoparticles surface can recognize FITC-labeled avidin and avidin on the surface of polystyrene microspheres by protein–protein binding. Finally, the CdTe/SiO2 composite nanoparticles with secondary antibody are used to label the MG63 osteosarcoma cell with primary antibody successfully, which demonstrates that the application of CdTe/SiO2 composite nanoparticles as fluorescent probes in bioassay and fluorescence imaging is feasible.
Co-reporter:Wenchao Dou, Chao Wang, Guannan Wang, Qiang Ma and Xingguang Su
The Journal of Physical Chemistry B 2008 Volume 112(Issue 40) pp:12681-12685
Publication Date(Web):September 13, 2008
DOI:10.1021/jp805345d
The interaction between the water-soluble anionic fluorescence conjugated polyelectrolytes PPESO3 (poly[2,5-bis(3-sulfonatopropoxy)-1,4-phenylethynylene-alt- 1,4-poly(phenylene ethynylene)]) and various surfactants has been studied in aqueous solution by UV−vis absorption spectra and fluorescence spectra. With the addition of surfactants, the aggregations of polymers are broken up. For eliminating the self-quenching effect of the fluorescent polymers, the photoluminescence of PPESO3 is dramatically enhanced. The photoluminescence of PPESO3 can be enhanced 6- to 12-fold with the addition of different surfactants, and at higher concentration of surfactants, the photostability of PPESO3 is also highly increased. A “micelle incorporation model” is proposed to explain the enhancement of photostability. To deeply understand the interaction processes between PPESO3 and surfactants, we systematically studied the fluorescence spectra changes of PPESO3 and the dynamic processes at different CTAB concentrations. All results prove the surfactants can simultaneously enhance the photoluminescence and photostability of water-soluble conjugated polyelectrolytes, and this method is very simple and powerful.
Co-reporter:Qiang Ma, Xinyan Wang, Yabing Li, Yuhua Shi, Xingguang Su
Talanta 2007 Volume 72(Issue 4) pp:1446-1452
Publication Date(Web):15 June 2007
DOI:10.1016/j.talanta.2007.01.058
The biocompatible semiconductor quantum dots (QDs) have unique photophysical properties, which provide important advantages over organic dyes and lanthanide probes in fluorescence labeling applications. In this work, multicolor quantum QD-encoded microspheres have been prepared via the layer-by-layer (LbL) assembly approach. Polystyrene microspheres of 3 μm diameter were used as templates for the deposition of different sized CdTe QDs/polyelectrolyte multilayers via electrostatic interactions. Two kinds of biofuntional multicolor microspheres with two different antibodies, anti-human IgG and anti-rabbit IgG were prepared. Human IgG and rabbit IgG can be detected as target antigens in the multiplexed fluoroimmunoassays. Furthermore, a novel microfluidic on-chip device was developed to detect two kinds of antigen-conjugated multicolor QD-encoded microspheres; the microspheres can be distinguished from each other based on their fluorescence signals.
Co-reporter:Xingguang Su;Qiang Ma;Xinyan Wang;Qinhan Jin;Yabing Li
Luminescence 2007 Volume 22(Issue 5) pp:438-445
Publication Date(Web):4 JUL 2007
DOI:10.1002/bio.982
Polystyrene fluorescent microspheres prepared by deposition of CdTe quantum dots (QDs) are used in an immunoassay in this study. CdTe QDs/polyelectrolyte multilayers on the surface of polystyrene microspheres have been formed by layer-by-layer self-assembly via electrostatic interactions. As a model antigen, rabbit IgG has been bound to the outermost layer of the fluorescent microspheres. The immunoreaction between fluorescent microspheres/rabbit IgG and the corresponding antibody was confirmed by change of the fluorescence spectrum and competitive immunoassay. This approach allowed detection of the antigen (rabbit IgG) in the range 1–500 mg/L, based on the change in the fluorescence intensity of the reporter (fluorescent microspheres/rabbit IgG). A novel microfluidic chip device with a laser-induced fluorescence system was established and used for the detection of fluorescent microspheres in this study. Copyright © 2007 John Wiley & Sons, Ltd.
Co-reporter:Yabing Li;Xinyan Wang;Qiang Ma
Luminescence 2007 Volume 22(Issue 1) pp:60-66
Publication Date(Web):6 NOV 2006
DOI:10.1002/bio.927
In this study, 573 nm quantum dots (QDs)-rabbit IgG–goat anti-rabbit IgG–638 nm QDs immunocomplexes were prepared, utilizing antigen–antibody interaction. 573 nm-emitting QDs were conjugated to antigen (rabbit IgG) and 638 nm-emitting QDs were conjugated to antibody (goat anti-rabbit IgG) via electrostatic/hydrophilic self-assembly, respectively. The mutual affinity of the antigen and antibody brought two kinds of QDs close enough to result in fluorescence resonance energy transfer (FRET) between them; the luminescence emission of 573 nm QDs was quenched, while that of 638 nm QDs was enhanced. The luminescence emission of 573 nm QDs could be recovered when the immunocomplexes were exposed to the unlabelled rabbit IgG antigen. The FRET efficiency (E) and the distance between the donor and the acceptor were calculated. Copyright © 2006 John Wiley & Sons, Ltd.
Co-reporter:Qiang Ma;Bing Li;Yabing Li;Xinyan Wang
Luminescence 2007 Volume 22(Issue 1) pp:1-8
Publication Date(Web):21 JUN 2006
DOI:10.1002/bio.917
Different sizes of CdTe semiconductor nanoparticles were prepared in aqueous solution. These nanoparticles exhibit narrow fluorescence with full width at half-maximum (FWHM) of 35–45 nm that spans the visible spectrum, and they also have high PL quantum yield with high resistance to photodegradation. In addition, CdTe quantum dot (QD)-labelled microspheres, comprising polystyrene (PS) cores and CdTe/polyelectrolyte (PE) shells, were also prepared by the layer-by-layer technique in this paper. The optical properties of the CdTe nanoparticles and CdTe-labelled microspheres were investigated by UV-Visible absorption and luminescence spectroscopy, and fluorescence microscopy was employed for microscopic identification behaviour of the luminescent microspheres. Copyright © 2006 John Wiley & Sons, Ltd.
Co-reporter:Qiang Ma, Xing-Guang Su, Xin-Yan Wang, Yi Wan, Chun-Lei Wang, Bai Yang, Qin-Han Jin
Talanta 2005 Volume 67(Issue 5) pp:1029-1034
Publication Date(Web):31 October 2005
DOI:10.1016/j.talanta.2005.04.036
The mouse immunoglobulin G (mouse IgG) as a kind of bio-molecule was labeled with two different luminescent colloidal semiconductor quantum dots (QDs), green-emitting CdTe quantum dots and red-emitting CdTe quantum dots in this work. As a result of the fluorescence resonance energy transfer (FRET) between the two different sizes nanoparticles with mouse IgG as the binding bridge, a significant enhancement of the emission of the red-emitting CdTe quantum dots and the corresponding quenching of the emission of green-emitting CdTe quantum dots were observed. The relationship between the concentration of the mouse immunoglobulin G and the fluorescence intensity ratio (Ia/Id) of acceptors and donors was studied also. Under optimal conditions, the calibration graph is linear over the range of 0.1–20.0 mg/L mouse IgG.
Co-reporter:Qidan Chen;Yi Wan;Qiang Ma;Zhangbi Lin;Qinhan Jin
Luminescence 2005 Volume 20(Issue 4‐5) pp:251-255
Publication Date(Web):31 AUG 2005
DOI:10.1002/bio.840
In this work, donor–acceptor complexes were formed based on antibody–antigen interactions. Immunoglobulin antigen (mouse-IgG) was effectively conjugated to mercaptopropyl acid-modified CdTe quantum dot synthesized in aqueous solution via electrostatic interaction, while organic dyes–tetramethylrhodamine isothiocyanate (TRITC) were attached to the corresponding antibody (anti-mouse IgG). The mutual affinity of the antigen and antibody brought the CdTe quantum dot and TRITC sufficiently close together to allow the resonance dipole–dipole coupling required for fluorescence resonance energy transfer to occur. The formation of immunocomplexes resulted in fluorescence resonance energy transfer from the CdTe quantum dot donors to the TRITC acceptors. Copyright © 2005 John Wiley & Sons, Ltd.
Co-reporter:Chao Wang, Xue Gao, Qiang Ma and Xingguang Su
Journal of Materials Chemistry A 2009 - vol. 19(Issue 38) pp:NaN7022-7022
Publication Date(Web):2009/08/07
DOI:10.1039/B909546B
In this paper, Mn2+-doped ZnSe quantum dots (Mn:ZnSe d-dots) are synthesized successfully by a nucleation–doping method in aqueous solution with mercaptopropionic acid as the stabilizer. The optimal precursor ratio and kind of stabilizer for obtaining Mn:ZnSe d-dots with good photoluminescence emission properties was studied in detail. Finally, the photostability of the resulting Mn:ZnSe d-dots was studied and the results showed that Mn:ZnSe d-dots are much more photostable than CdTe quantum dots synthesized in aqueous solution, indicating their potential as a new generation of fluorescent labels for biological assays, imaging of cells and tissues, even in vivo investigations.
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