A novel sensitive electrochemical immunoassay with colloidal gold as the antibody labeling tag and subsequent signal amplification by silver enhancement is described. Colloidal gold was treated by a light-sensitive si...A novel sensitive electrochemical immunoassay with colloidal gold as the antibody labeling tag and subsequent signal amplification by silver enhancement is described. Colloidal gold was treated by a light-sensitive silver enhancement system which made silver deposit on the surface of colloidal gold(form Au/Ag core-shell structure), followed by the release of the metallic silver atoms anchored on the antibody by oxidative dissolution of them in an acidic solution and the indirect determination of the dissolved Ag + ions by anodic stripping voltammetry(ASV) at a carbon fiber microelectrode. The electrochemical signal is directly proportional to the amount of analyte(goat IgG) in the standard or a sample. The method was evaluated by means of a noncompetitive heterogeneous immunoassay of immunoglobulin G(IgG) with a concentration as low as 0.2 ng/mL. The high performance of the method is related to the sensitive ASV determination of silver(Ⅰ) at a carbon fiber microelectrode and to the release of a large number of Ag + ions from each silver shell anchored on the analyte(goat IgG).展开更多
A novel, sensitive anodic stripping volammetric immunoassay was developed based on silver-enhanced immuno-gold label. The immunoreaction was performed in a polystyrene microwell by using the sandwich format. Primary a...A novel, sensitive anodic stripping volammetric immunoassay was developed based on silver-enhanced immuno-gold label. The immunoreaction was performed in a polystyrene microwell by using the sandwich format. Primary antibodies specific for C-3(complement Ⅲ) were adsorbed passively on the walls of a polystyrene microwell. The C-3 analyte was first captured by the primary antibody and then sandwiched by a secondary colloidal gold-labeled antibody. The addition of the silver enhancement solution results in the precipitation of a large amount of silver on colloidal gold labels due to the catalytic reduction which, after silver metal dissolution in an acidic solution, was determined by anodic stripping voltammetry(ASV) at a glassy-carbon electrode. The influence of some immunoassay conditions upon the anodic stripping peak current was examined and optimized. The anodic stripping peak current depended linearly on the logarithm of C-3 mass concentration over the range of 7.2 ng/mL to 7.33 μg/mL and a detection limit as low as 7ng/mL is achieved. The anodic stripping volammetric immunoassay was applied to the determination of C-3 concentration in human serum with satisfactory results.展开更多
基金Supportted by the National Natural Science Foundation of China( No.2 0 0 730 16 ,6 0 2 710 2 0 ),86 3projects( No.2 0 0 2 AA302203)and973projects( No.G19990 6 4 5 0 4 )
文摘A novel sensitive electrochemical immunoassay with colloidal gold as the antibody labeling tag and subsequent signal amplification by silver enhancement is described. Colloidal gold was treated by a light-sensitive silver enhancement system which made silver deposit on the surface of colloidal gold(form Au/Ag core-shell structure), followed by the release of the metallic silver atoms anchored on the antibody by oxidative dissolution of them in an acidic solution and the indirect determination of the dissolved Ag + ions by anodic stripping voltammetry(ASV) at a carbon fiber microelectrode. The electrochemical signal is directly proportional to the amount of analyte(goat IgG) in the standard or a sample. The method was evaluated by means of a noncompetitive heterogeneous immunoassay of immunoglobulin G(IgG) with a concentration as low as 0.2 ng/mL. The high performance of the method is related to the sensitive ASV determination of silver(Ⅰ) at a carbon fiber microelectrode and to the release of a large number of Ag + ions from each silver shell anchored on the analyte(goat IgG).
文摘A novel, sensitive anodic stripping volammetric immunoassay was developed based on silver-enhanced immuno-gold label. The immunoreaction was performed in a polystyrene microwell by using the sandwich format. Primary antibodies specific for C-3(complement Ⅲ) were adsorbed passively on the walls of a polystyrene microwell. The C-3 analyte was first captured by the primary antibody and then sandwiched by a secondary colloidal gold-labeled antibody. The addition of the silver enhancement solution results in the precipitation of a large amount of silver on colloidal gold labels due to the catalytic reduction which, after silver metal dissolution in an acidic solution, was determined by anodic stripping voltammetry(ASV) at a glassy-carbon electrode. The influence of some immunoassay conditions upon the anodic stripping peak current was examined and optimized. The anodic stripping peak current depended linearly on the logarithm of C-3 mass concentration over the range of 7.2 ng/mL to 7.33 μg/mL and a detection limit as low as 7ng/mL is achieved. The anodic stripping volammetric immunoassay was applied to the determination of C-3 concentration in human serum with satisfactory results.
