Xiue Jiang

Northeast Institute of Geography and Agroecology, Beijing, Beijing Shi, China

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Publications (17)61.8 Total impact

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    ABSTRACT: [Ru(bpy)3]2+-doped silica (RuSi) nanoparticles were synthesized by using a water/oil microemulsion method. Stable electrochemiluminescence (ECL) was obtained when the RuSi nanoparticles were immobilized on a glassy carbon electrode by using tripropylamine (TPA) as a coreactant. Furthermore, the ECL of the RuSi nanoparticles with layer-by-layer biomolecular coatings was investigated. Squential self-assembly of the polyelectrolytes and biomolecules on the RuSi nanoparticles gave nanocomposite suspensions, the ECL of which decreased on increasing the number of bilayers. Moreover, factors that affected the assembly and ECL signals were investigated. The decrease in ECL could be assigned to steric hindrance and limited diffusion of the coreactant molecules in the silica matrix after they were attached to the biomolecules. Since surface modification of the RuSi nanoparticles can improve their biocompatibility and prevent leaking of the [Ru(bpy)3]2+ ions, the RuSi nanoparticles can be readily used as efficient and stable ECL tag materials in immunoassay and DNA detection.
    Chemistry 02/2008; 14(12):3687-93. · 5.83 Impact Factor
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    ABSTRACT: A detailed investigation on the adsorption behavior of Neutral Red (NR) molecules on mercaptoethane sulfonate-monolayer protected gold clusters (MES-MPCs) has been conducted by the spectroscopic method. It is found that cationic NR molecules are adsorbed on the negatively charged MPCs surfaces via electrostatic attractive forces. The absorption study shows that the optical properties of NR molecules are significantly influenced upon the adsorption. Based on the electrostatic adsorption nature and the excellent stability of MES-MPCs against the electrolytes, this association can be released by the addition of electrolyte salts, which can be monitored by both absorption and fluorescence spectroscopy. In addition, dication Ca2+ is found to be more effective in the release of NR than univalent Na+. Moreover, the MES-MPCs exert energy transfer quenching of NR fluorescence by both static and dynamic quenching. However, static quenching seems to be the dominating quenching mechanism. Furthermore, this energy transfer quenching exhibits strong dependence of Au core size, and 5.0 nm MPCs show stronger ability in quenching the NR fluorescence than that of 2.7 nm MPCs.
    Journal of Photochemistry and Photobiology A: Chemistry. 01/2007;
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    ABSTRACT: The redox-induced conformational equilibrium of cytochrome c (cyt c) adsorbed on DNA-modified metal electrode and the interaction mechanism of DNA with cyt c have been studied by electrochemical, spectroscopic and spectroelectrochemical techniques. The results indicate that the external electric field induces potential-dependent coordination equilibrium of the adsorbed cyt c between its oxidized state (with native six-coordinate low-spin and non-native five-coordinate high-spin heme configuration) and its reduced state (with native six-coordinate low-spin heme configuration) on DNA-modified metal electrode. The strong interactions between DNA and cyt c induce the self-aggregation of cyt c adsorbed on DNA. The orientational distribution of cyt c adsorbed on DNA-modified metal electrode is potential-dependent, which results in the deviation from an ideal Nernstian behavior of the adsorbed cyt c at high electrode potentials. The electric-field-induced increase in the activation barrier of proton-transfer steps attributed to the rearrangement of the hydrogen bond network and the self-aggregation of cyt c upon adsorption on DNA-modified electrode strongly decrease the interfacial electron transfer rate. In addition, the strongly Coulombic interactions between DNA and cyt c only disturb the microenvironment of the heme, and do not affect the states of heme ligation and spin. The secondary structure of the adsorbed cyt c is retained, while the conformation of DNA is changed from the B form DNA to A form DNA.
    Biosensors & Bioelectronics 08/2006; 22(1):49-55. · 6.45 Impact Factor
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    ABSTRACT: Didodecyldimethylammonium bromide (DDAB) lipid bilayer-protected gold nanoparticles (AuNPs), which were stable and hydrophilic, were synthesized by in situ reduction of HAuCl(4) with NaBH(4) in an aqueous medium in the presence of DDAB. As-prepared nanoparticles were characterized by UV-vis spectra, transmission electron microscopy, dynamic light scattering analysis, and X-ray photoelectron spectroscopy. All these data supported the formation of AuNPs. Fourier transform infrared spectroscopy (FTIR) and differential thermal analysis/thermogravimetric analysis data revealed that DDAB existed in a bilayer structure formed on the particle surface, resulting in a positively charged particle surface. The FTIR spectra also indicated that the DDAB bilayer coated on the surface of AuNPs was probably in the ordered gel phase with some end-gauche defects. On the basis of electrostatic interactions between such AuNPs and anionic polyelectrolyte poly(sodium 4-styrenesulfonate) (PSS), we successfully fabricated (PSS/AuNP)(n)() multilayers on a cationic polyelectrolyte poly(ethylenimine) coated indium tin oxide substrate via the layer-by-layer self-assembly technique and characterized as-formed multilayers with UV-vis spectra and atomic force microscopy.
    Langmuir 04/2006; 22(6):2838-43. · 4.38 Impact Factor
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    Lei Zhang, Xiue Jiang, Li Niu, Shaojun Dong
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    ABSTRACT: Fully sulfonated polyaniline nano-particles, nano-fibrils and nano-networks have been achieved for the first time by electrochemical homopolymerization of orthanilic acid using a three-step electrochemical deposition procedure in a mixed solvent of acetonitrile (ACN) and water. The diameter of the uniform nano-particles is about 60 nm, and the nano-fibrils can be organized in two-dimensional (2D) or three-dimensional (3D) non-periodic networks with good electrical contact. Average distance between contacts is about 850 and 600nm for a 2D and 3D system, respectively. The details of the poly(orthanilic acid) (POA) nano-structure were examined with a field emission scanning electron microscope (SEM). The structure and properties of POA were characterized with FTIR, UV-vis and electrochemical methods. The 3D POA nano-networks coated platinum electrode gave a direct electrochemical behavior of horse heart cytochrome c (Cyt c) immobilized on this electrode surface, a pair of well-defined redox waves with formal potential (E( degrees ')) of -0.032 V (versus Ag/AgCl) was achieved. The interaction between Cyt c and POA makes the formal potential shift negatively compared to that of Cyt c in solution. Spectrophotometric and electrochemical methods were used to investigate the interaction of Cyt c with POA. The immobilized Cyt c in the nano-networks POA film maintained its activity, showing a surface-controlled electrode process with the electron transfer rate constant (k(s)) of 21s(-1) and a of 0.53, and could be used for the electrocatalytic reduction of hydrogen peroxide. The quantitative determination of Cyt c by differential pulse voltammetry (DPV) using the fully sulfonated 3D POA nano-networks film coated platinum electrode was also studied.
    Biosensors & Bioelectronics 02/2006; 21(7):1107-15. · 6.45 Impact Factor
  • Xiue Jiang, Lei Zhang, Shaojun Dong
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    ABSTRACT: Stable electroactive film of poly(aniline-co–o-aminobenzenesulfonic acid) three-dimensional tubal net-works was assembled on indium oxide glass (ITO) successfully, and the cytochrome c was immobilized on the matrix by the electrostatic interactions. The adsorbed cytochrome c showed a good electrochemical activity with a pair of well-defined redox waves in pH 6.2 phosphate buffer solution, and the adsorbed protein showed more faster electron transfer rate (12.9s−1) on the net-works matrix than those of on inorganic porous or even nano-materials reported recently. The immobilized cytochrome c exhibited a good electrocatalytic activity and amperometric response (2s) for the reduction of hydrogen peroxide (H2O2). The detection limit for H2O2 was 1.5μM, and the linear range was from 3μM to 1mM. Poly(aniline-co-o-aminobenzenesulfonic acid) three-dimensional tubal net-works was proved to be a good matrix for protein immobilization and biosensor preparation.
    Electrochemistry Communications - ELECTROCHEM COMMUN. 01/2006; 8(7):1137-1141.
  • Li Shang, Xiue Jiang, Shaojun Dong
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    ABSTRACT: In this paper, the binding of neutral red (NR) to bovine serum albumin (BSA) under physiological conditions has been studied by spectroscopy method including fluorescence, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy. The Stern–Volmer fluorescence quenching constant (KSV), binding constant (Kb) and the number of binding sites (n) were measured by fluorescence quenching method. Fluorescence experiments were also performed at different ionic strengths. It was found KSV was ionic strength dependent, which indicated the electrostatic interactions were part of the binding forces. The distance r between donor (BSA) and acceptor (NR) was obtained according to Foster's non-radiative energy transfer theory. CD spectroscopy and FT-IR spectroscopy were used to investigate the structural information of BSA molecules on the binding of NR, and the results showed no change of BSA conformation in our experimental conditions.
    Journal of Photochemistry and Photobiology A-chemistry - J PHOTOCHEM PHOTOBIOL A-CHEM. 01/2006; 184(1):93-97.
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    ABSTRACT: Conformational changes of β-lactoglobulin (β-LG) induced by anionic phospholipid (dimyristoylphosphatidylglycerol, DMPG) at physiological conditions (pH 7.0) have been investigated by UV–VIS, circular dichroism (CD) and fluorescence spectra. The experimental results suggest that β-LG–DMPG interactions cause β-LG a structural reorganization of the secondary structure elements accompanied by an increase in α-helical content, and a loosening of the protein tertiary structure. The interaction forces between β-LG and DMPG are further evaluated by fluorescence spectra. The fluorescence spectral data show that conformational changes in the protein are driven by electrostatic interaction at first, then by hydrophobic interaction between a protein with a negative net charge and a negatively charged phospholipid.
    Biophysical Chemistry 01/2006; 121(3):218-223. · 2.28 Impact Factor
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    ABSTRACT: The interaction of neutral red (NR) with calf thymus DNA (CT DNA) was investigated by spectrometric (UV-vis, circular dichroism and fluorescence) and voltammetric techniques. It was shown that the interaction of NR with DNA depended on the values of R (R is defined as the ratio of the concentration of NR to that of CT DNA) and pH of the solution. NR intercalated into CT DNA base pairs at lower R value (R < 2.4) and following by NR aggregating along the helical surface of DNA at higher R value (R > 2.4) in pH 6.0 solution. Interestingly, we found that at lower R value, NR intercalated into CT DNA with its long axis perpendicular or parallel to the dyad axis of DNA in the solution of pH 6.0. While in pH 7.0 solution, NR bound with CT DNA through intercalation and electrostatic interactions. The electrochemical inactive complexes, NR-2CT DNA, 3NR-CT DNA, and NR-CT DNA were formed when NR interacted with nucleic acids in pH 6.0 and 7.2 solutions, respectively. The corresponding intrinsic binding constants for these complexes were obtained by UV-vis and fluorescence spectrometric methods, respectively. The CD spectra showed that the conformation of CT DNA was converted from right-handed B-DNA to left-handed Z-DNA due to the aggregating of NR along the surface of DNA in pH 6.0 solution, whereas a conversion from B-DNA to C-DNA was induced due to the interaction of DNA with NR in pH 7.2 solution. Finally, two binding modes of NR with CT DNA in aqueous with different values of pH were shown in the scheme.
    Biophysical Chemistry 11/2005; 118(1):42-50. · 2.28 Impact Factor
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    ABSTRACT: The orientation and conformation of adsorbed cytochrome c (cyt c) at the interface between an electrode modified with colloidal Au and a solution were studied by electrochemical, spectroscopic, and spectroelectrochemical techniques. The results indicate that the colloidal Au monolayer formed via preformation of an organic self-assembled monolayer (SAM) can increase the electronic coupling between the SAM and cyt c in the same manner as bifunctional molecular bridges, one functional group of which is bound to the electrode surface while the other interacts with the protein surface. The approach of cyt c to the modified electrode/solution interface can be assisted by strong interactions of the intrinsic charge of colloidal particles with cyt c, while the heme pocket remains almost unchanged due to the screening effect of the negatively charged field created by the intrinsic charge. The conformational changes of cyt c induced by its adsorption at a bare glassy carbon electrode/solution interface and the effect of the electric field on the ligation state of the heme can be avoided at the colloidal-Au-modified electrode/solution interface. Finally, a possible model for the adsorption orientation of cyt c at the colloidal-Au-modified electrode/solution interface is proposed.
    ChemPhysChem 09/2005; 6(8):1613-21. · 3.35 Impact Factor
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    ABSTRACT: Gold nanoparticles have been attached onto glassy carbon electrode surface through sulfhydryl-terminated monolayer and characterized by X-ray photoelectron spectroscopy, atomic force microscopy, electrochemical impedance spectroscopy and cyclic voltammetry. The gold nanoparticles-attached glassy carbon electrodes have been applied to the immobilization/adsorption of hemoglobin, with a monolayer surface coverage of about 2.1 x 10(-10) mol cm(-2), and consequently obtained the direct electrochemistry of hemoglobin. Gold nanoparticles, acting as a bridge of electron transfer, can greatly promote the direct electron transfer between hemoglobin and the modified glassy carbon electrode without the aid of any electron mediator. In phosphate buffer solution with pH 6.8, hemoglobin shows a pair of well-defined redox waves with formal potential (E0') of about -0.085 V (versus Ag/AgCl/saturated KCl). The immobilized hemoglobin maintained its biological activity, showing a surface controlled electrode process with the apparent heterogeneous electron transfer rate constant (ks) of 1.05 s(-1) and charge-transfer coefficient (a) of 0.46, and displays the features of a peroxidase in the electrocatalytic reduction of hydrogen peroxide. A potential application of the hemoglobin-immobilized gold nanoparticles modified glassy carbon electrode as a biosensor to monitor hydrogen peroxide has been investigated. The steady-state current response increases linearly with hydrogen peroxide concentration from 2.0 x 10(-6) to 2.4 x 10(-4) M. The detection limit (3sigma) for hydrogen peroxide is 9.1 x 10(-7) M.
    Biosensors & Bioelectronics 09/2005; 21(2):337-45. · 6.45 Impact Factor
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    ABSTRACT: Electrochemical redox processes of bovine heart cytochrome c were investigated by in situ UV-vis and CD spectroelectrochemistry at bare glassy carbon electrode (GCE) and single-wall carbon nanotubes (SWNTs) modified glassy carbon electrode (SWNTs/GCE) using a long optical path thin layer cell. The spectra obtained at GCE and SWNTs/GCE reflect electrode surface microstructure-dependent changes in protein conformation during redox transition. Potential-dependent conformational distribution curves of cytochrome c obtained by analysis of in situ circular dichroism (CD) spectra using singular value decomposition least square (SVDLS) method show that SWNTs can retain conformation of cytochrome c. Some parameters of the electrochemical reduction process, i.e. the product of electron transfer coefficient and number of electrons (alpha n = 0.3), apparent formal potential (E0' = 0.04 V), were obtained by double logarithmic analysis and standard heterogeneous electron transfer rate constant k0 was obtained by electrochemistry and double logarithmic analysis, respectively.
    Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 04/2005; 61(5):943-51. · 1.98 Impact Factor
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    ABSTRACT: The conformational changes of bovine heart cytochrome c (cyt c) induced by the adsorption on gold nanoparticles with different sizes have been investigated by electronic absorption, circular dichroism (CD), and Fourier transform infrared spectra. The combination of these techniques can give complementary information about adsorption-induced conformational changes. The results show that there are different conformational changes for cyt c adsorbed on gold nanoparticles with different sizes due to the different interaction forces between cyt c and gold nanoparticles. The colloidal gold concentration-dependent conformation distribution curves of cyt c obtained by analysis of CD spectra using the singular value decomposition least-squares method show that the coverage of cyt c on the gold nanoparticles surface also affects the conformational changes of the adsorbed cyt c.
    Biomacromolecules 01/2005; 6(1):46-53. · 5.37 Impact Factor
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    ABSTRACT: The thermal stability of cytochrome c (cyt c) after Au-nanoparticle-directed association has been studied by various spectroscopic (electronic absorption, resonance Raman, and circular dichroism) and electrochemical methods. The results show that the thermal stability of the Au-cyt c superstructure biocomposite formed by the electrostatic and hydrophobic interactions among the associated proteins increases significantly. It is mainly caused by strong hydrophobicity of the associated cyt c in Au-cyt c superstructure at high temperature, which results from the compact secondary structure and the packing of hydrophobic side chains around the Trp 59 and heme. In addition, the formation of bis-His configuration of heme is facilitated by the tightly self-associated state of cyt c in the Au-cyt c superstructure. The electrostatic coupling of the opposite charges among shells of the adsorbed proteins due to the formation of the superstructure biocomposite can reduce repulsions among the same charges in protein. These factors are also important for enhancing the stability of the associated cyt c. Furthermore, the voltammetric behavior of Au-cyt c at DNA modified glassy carbon electrode has been investigated for extending the application of Au-cyt c.
    Biomacromolecules 01/2005; 6(6):3030-6. · 5.37 Impact Factor
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    ABSTRACT: pH-dependent processes of bovine heart ferricytochrome c have been investigated by electronic absorption and circular dichroism (CD) spectra at functionalized single-wall carbon nanotubes (SWNTs) modified glass carbon electrode (SWNTs/GCE) using a long optical path thin layer cell. These methods enabled the pH-dependent conformational changes arising from the heme structure change to be monitored. The spectra obtained at functionalized SWNTs/GCE reflect electrode surface microstructure-dependent changes for pH-induced protein conformation, pK(a) of alkaline transition and structural microenvironment of the ferricytochrome c heme. pH-dependent conformational distribution curves of ferricytochrome c obtained by analysis of in situ CD spectra using singular value decomposition least square (SVDLS) method show that the functionalized SWNTs can retain native conformational stability of ferricytochrome c during alkaline transition.
    Biophysical Chemistry 09/2004; 110(3):203-11. · 2.28 Impact Factor
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    ABSTRACT: Gold nanoparticles (3.1-5.0 nm in size) surface-derivatized with both electroactive and nonelectroactive self-assembled monolayers were synthesized. The surface-derivatized electroactive particles can be easily oxidized/reduced at an electrode surface based on the diffusion-controlled current-voltage curve observed in cyclic voltammetry measurements. Spectroelectrochemical investigation demonstrated that the maximum absorbance of the nanoparticles in their oxidized state red-shifted compared with their reduced state to a different extent according to their size distribution. In the case of the particles surface-derivatized with nonelectroactive monolayers, much less shift was observed. This study showed that surface plasmon absorbance of gold nanoparticles was not only related to core charge states but was also influenced by surface charge states as well.
    Langmuir 04/2004; 20(7):2519-22. · 4.38 Impact Factor
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    Macromolecular Rapid Communications 11/2003; 24(17):1024 - 1028. · 4.93 Impact Factor

Publication Stats

274 Citations
61.80 Total Impact Points

Institutions

  • 2003–2007
    • Northeast Institute of Geography and Agroecology
      • State Key Laboratory of Electroanalytical Chemistry
      Beijing, Beijing Shi, China
  • 2005–2006
    • Chinese Academy of Sciences
      • State Key Laboratory of Electroanalytical Chemistry
      Peping, Beijing, China