It is a challenge to thoroughly understand the astonishing difference in catalytic activity between nanogold and bulk gold for some oxidation reactions. In this work,the Au–O interactions in various surroundings were...It is a challenge to thoroughly understand the astonishing difference in catalytic activity between nanogold and bulk gold for some oxidation reactions. In this work,the Au–O interactions in various surroundings were investigated by DFT calculations and compared with the Ag–O interactions. We have found the three points.First,only Au–O bond can be significantly strengthened by the linear O–Au–O structure. Second,the Au–O bond is always stronger than the Ag–O bond when the bonds are embedded in common surroundings. Third,the Au–O bond becomes weaker than the Ag–O bond when the number of neighboring Au atoms becomes large,because the Au–O interactions are suppressed by the presence of neighboring gold atoms. The origin of these three points can be attributed to wider spatial extension of d orbitals of gold,induced by strong relativistic effects. The strong relativistic effects make nanogold with smaller coordinate numbers highly active due to the ease in forming strong Au–O bonds,especially for the O–Au–O bond,whereas gold atoms in bulk with larger coordination numbers chemically inert due to the strong suppression by neighboring gold atoms destabilizing the O–Au–O bond.展开更多
In this paper, a new method for the modification of glass carbon electrode (GCE) by polyethylenimine (PEI) and nano-gold (Au-colloid) was established to explore sensitive techniques for voltammetric determination of d...In this paper, a new method for the modification of glass carbon electrode (GCE) by polyethylenimine (PEI) and nano-gold (Au-colloid) was established to explore sensitive techniques for voltammetric determination of diethylstilbestrol. Compared with bare GCE, the peak current at the potential of 0.45 V is increased notably at PEI and PEI-nanogold modified electrode both by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). This kind of electrode allows the detection of low concentration of diethylstilbestrol in the range of 0.03～12 mg/L by DPV measurement. Other optimizations for experimental conditions were also discussed in detail.展开更多
A rapid, inexpensive, reliable, and flexible quantitative immunoassay for cardiac troponin I （cTnI） based on the concepts of one-step dual monoclonal antibody “sandwich” principle. The low density protein array, t...A rapid, inexpensive, reliable, and flexible quantitative immunoassay for cardiac troponin I （cTnI） based on the concepts of one-step dual monoclonal antibody “sandwich” principle. The low density protein array, the nanogold probe, and the silver enhancement on the gold particle were provided. The whole detection procedure of the assay could be fulfilled within 40 min with the pretreated colloidal gold-labeled detection antibody and supporting substrate. The assay showed good specific response to cTnI with very low cross-reactivity ratio to the skeletal isoforms of troponin I （sTnI）, cardiac troponin T （cTnT）, and myoglobin. 588 serum samples were assayed simultaneously by enzyme-linked immuno sorbent assay （ELISA） and this colloidal gold method to test the validity of the method and the data were analyzed using the statistical package SPSS version 11.0 （SPSS Inc.）. There was no significant difference between these two assays （P=0.66〉0.05）. The agreement between this method （〉 or 〈0.3 ng/mL） and ELISA was 86%.展开更多
A nanostructured polymer film incorporated gold nanoparticles modified electrode was fabricated. The fabrication process involved a previous electropolymerization of aspartic acid and followed by the eletrodeposition ...A nanostructured polymer film incorporated gold nanoparticles modified electrode was fabricated. The fabrication process involved a previous electropolymerization of aspartic acid and followed by the eletrodeposition of gold nano-particles on the glassy carbon electrode. The resulting poly (aspartic acid)-nanogold modified electrode (PAA- nano-Au/GCE) was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectros-copy (EIS). A higher catalytic activity was obtained to electrocatalytic oxidation of dopamine (DA), ascorbic acid (AA) and uric acid (UA) due to the enhanced peak current and well-defined peak separations compared with three, bare GCE, PAA/GCE and nano-Au/GCE. Simultaneous determination of DA, AA, and UA were studied by voltammetry. The linear range of 5.0 × 10-7 - 1.0 × 10-4 M for DA, 5.0 × 10-6 - 2.0 × 10-3 M for AA and 5.0 × 10-6 - 1.0 × 10-3 M for UA was obtained. The detection limit was calculated for DA, AA and UA as being 6.5 × 10-8 M, 5.6 × 10-7 M and 3.0 × 10-7 M, respectively (S/N = 3). The practical application of the present modified electrode was demonstrated by the determination of DA, AA and UA in calf serum and fetal calf serum samples.展开更多
A kind of 9 nm gold nanoparticles was prepared with the trisodium citrate and used to label goat anti-human IgG to obtain an IgG immunoresonance scattering spectral probe. In pH 5.8 buffer solution and in the presence...A kind of 9 nm gold nanoparticles was prepared with the trisodium citrate and used to label goat anti-human IgG to obtain an IgG immunoresonance scattering spectral probe. In pH 5.8 buffer solution and in the presence of polyethylene glycol （PEG）, the immune reaction between gold-labeled goat anti-human IgG and IgG took place, and the resonance scattering intensity at 580 nm （I580nm） was enhanced greatly. The enhanced intensity AIRS is pro- portional to the IgG concentration from 1.3 to 1.5 X 10^3 ng.mL^-1, with a detection limit of 0.78 ng.mL ^-1. This assay showed high sensitivity and good selectivity for quantitative determination of IgG in human serum, with satisfactory results.展开更多
In the pH 7.4 Na2HPO4-NaH2PO4 buffer solution, the cationic surfactant （CS） interacted with nanogold particles （NG） to form NG aggregations （NGA） that resulted in its color changing from wine red to blue-violet....In the pH 7.4 Na2HPO4-NaH2PO4 buffer solution, the cationic surfactant （CS） interacted with nanogold particles （NG） to form NG aggregations （NGA） that resulted in its color changing from wine red to blue-violet. NG has a strong catalysis on the formic acid-phosphomolybdic acid （PMo） colored reaction, but that of the NGA catalysis is weak. With the increase of CS concentration, the NGA increased and the NG decreased, the catalysis decreased and the absorption value at 700 nm decreased linearly. The concentrations of 6.25-250 nmol/L tetradecyl dimethyl benzyl ammonium chloride （TDBAC）, 0.625-250 nmol/L cetyltrimethyl ammonium bromide （CTMAB） and 12.5 -500 nmol-L 1 dodecyldimethylbenzyl ammonium chloride （DDBAC） had good linear responses to the decreased absorption value （AA70o nm）, with molar absorption coefficients of 2.2 × 106, 2.1 × 106 and 9 ×105 Lomol 1.cm 1 respectively. This method was simple, highly sensitive and low-cost.展开更多
基金supported by Grant-in-Aid for Specially Promoted Research Grant no.19001005 from the Ministry of Education,Culture,Sports,Science and Technology of Japan (MEXT)supported by the Management Expenses Grants for National Universities Corporations from MEXTJapan Science and Technology Agency (JST),Core Research for Evolutional Science and Technology (CREST)
文摘It is a challenge to thoroughly understand the astonishing difference in catalytic activity between nanogold and bulk gold for some oxidation reactions. In this work,the Au–O interactions in various surroundings were investigated by DFT calculations and compared with the Ag–O interactions. We have found the three points.First,only Au–O bond can be significantly strengthened by the linear O–Au–O structure. Second,the Au–O bond is always stronger than the Ag–O bond when the bonds are embedded in common surroundings. Third,the Au–O bond becomes weaker than the Ag–O bond when the number of neighboring Au atoms becomes large,because the Au–O interactions are suppressed by the presence of neighboring gold atoms. The origin of these three points can be attributed to wider spatial extension of d orbitals of gold,induced by strong relativistic effects. The strong relativistic effects make nanogold with smaller coordinate numbers highly active due to the ease in forming strong Au–O bonds,especially for the O–Au–O bond,whereas gold atoms in bulk with larger coordination numbers chemically inert due to the strong suppression by neighboring gold atoms destabilizing the O–Au–O bond.
文摘In this paper, a new method for the modification of glass carbon electrode (GCE) by polyethylenimine (PEI) and nano-gold (Au-colloid) was established to explore sensitive techniques for voltammetric determination of diethylstilbestrol. Compared with bare GCE, the peak current at the potential of 0.45 V is increased notably at PEI and PEI-nanogold modified electrode both by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). This kind of electrode allows the detection of low concentration of diethylstilbestrol in the range of 0.03～12 mg/L by DPV measurement. Other optimizations for experimental conditions were also discussed in detail.
基金supported by the fund of“135”key laboratory of Jiangsu provincethe high-tech research program of Jiangsu province+1 种基金the Chinese Post Doctoral Science Foundation,the National Natural Science Foundation of China(No.60571032)the Trans-Century Training Programme Foundaion for the Talents by the Ministry of Education of China.
文摘A rapid, inexpensive, reliable, and flexible quantitative immunoassay for cardiac troponin I （cTnI） based on the concepts of one-step dual monoclonal antibody “sandwich” principle. The low density protein array, the nanogold probe, and the silver enhancement on the gold particle were provided. The whole detection procedure of the assay could be fulfilled within 40 min with the pretreated colloidal gold-labeled detection antibody and supporting substrate. The assay showed good specific response to cTnI with very low cross-reactivity ratio to the skeletal isoforms of troponin I （sTnI）, cardiac troponin T （cTnT）, and myoglobin. 588 serum samples were assayed simultaneously by enzyme-linked immuno sorbent assay （ELISA） and this colloidal gold method to test the validity of the method and the data were analyzed using the statistical package SPSS version 11.0 （SPSS Inc.）. There was no significant difference between these two assays （P=0.66〉0.05）. The agreement between this method （〉 or 〈0.3 ng/mL） and ELISA was 86%.
文摘A nanostructured polymer film incorporated gold nanoparticles modified electrode was fabricated. The fabrication process involved a previous electropolymerization of aspartic acid and followed by the eletrodeposition of gold nano-particles on the glassy carbon electrode. The resulting poly (aspartic acid)-nanogold modified electrode (PAA- nano-Au/GCE) was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectros-copy (EIS). A higher catalytic activity was obtained to electrocatalytic oxidation of dopamine (DA), ascorbic acid (AA) and uric acid (UA) due to the enhanced peak current and well-defined peak separations compared with three, bare GCE, PAA/GCE and nano-Au/GCE. Simultaneous determination of DA, AA, and UA were studied by voltammetry. The linear range of 5.0 × 10-7 - 1.0 × 10-4 M for DA, 5.0 × 10-6 - 2.0 × 10-3 M for AA and 5.0 × 10-6 - 1.0 × 10-3 M for UA was obtained. The detection limit was calculated for DA, AA and UA as being 6.5 × 10-8 M, 5.6 × 10-7 M and 3.0 × 10-7 M, respectively (S/N = 3). The practical application of the present modified electrode was demonstrated by the determination of DA, AA and UA in calf serum and fetal calf serum samples.
基金Project supported by the National Natural Science Foundation of China （Nos. 20667001, 20365001）, Natural Science Foundation of Guangxi （No. 2060213） and the Foundation of New Century Ten-Hundred-Thousand Talents of Guangxi.
文摘A kind of 9 nm gold nanoparticles was prepared with the trisodium citrate and used to label goat anti-human IgG to obtain an IgG immunoresonance scattering spectral probe. In pH 5.8 buffer solution and in the presence of polyethylene glycol （PEG）, the immune reaction between gold-labeled goat anti-human IgG and IgG took place, and the resonance scattering intensity at 580 nm （I580nm） was enhanced greatly. The enhanced intensity AIRS is pro- portional to the IgG concentration from 1.3 to 1.5 X 10^3 ng.mL^-1, with a detection limit of 0.78 ng.mL ^-1. This assay showed high sensitivity and good selectivity for quantitative determination of IgG in human serum, with satisfactory results.
基金This work was supported by the National Natural Science Foundation of China （Nos. 21075023, 20965002, 20865002）, the Natural Science Foundation of Guangxi （No. 099102 l z） and the Research Funds of Guangxi Water Conservancy.
文摘In the pH 7.4 Na2HPO4-NaH2PO4 buffer solution, the cationic surfactant （CS） interacted with nanogold particles （NG） to form NG aggregations （NGA） that resulted in its color changing from wine red to blue-violet. NG has a strong catalysis on the formic acid-phosphomolybdic acid （PMo） colored reaction, but that of the NGA catalysis is weak. With the increase of CS concentration, the NGA increased and the NG decreased, the catalysis decreased and the absorption value at 700 nm decreased linearly. The concentrations of 6.25-250 nmol/L tetradecyl dimethyl benzyl ammonium chloride （TDBAC）, 0.625-250 nmol/L cetyltrimethyl ammonium bromide （CTMAB） and 12.5 -500 nmol-L 1 dodecyldimethylbenzyl ammonium chloride （DDBAC） had good linear responses to the decreased absorption value （AA70o nm）, with molar absorption coefficients of 2.2 × 106, 2.1 × 106 and 9 ×105 Lomol 1.cm 1 respectively. This method was simple, highly sensitive and low-cost.
