基于胶体金标记的阳极溶出伏安免疫分析用于免疫球蛋白G的测定

Anodic Stripping Immunoassay Based on Gold Label for Determination of Immunoglobulin G

提出了一种基于胶体金标记的阳极溶出伏安免疫分析方法。免疫反应在聚苯乙烯微孔板中以夹心分析模式进行，通过物理吸附将兔抗人免疫球蛋白G（IgG）抗体固定于微孔板上，与相应抗原IgG发生免疫反应后，再通过夹心模式捕获相应的纳米金标记的羊抗人IgG抗体，然后再与金标羊抗人IgG抗体和金标兔抗羊二抗形成的免疫复合物反应，在微孔板上进一步引入大量的纳米金，将金溶解后，在碳糊电极上用阳极溶出伏安法（ASV）对金离子进行检测，溶出峰电流的大小间接与待分析物IgG的浓度成正比。对免疫分析的一些实验条件进行了优化。阳极溶出峰电流与IgG的对数浓度在1．1～1143ng／mL范围内呈良好的线性关系，检出限为1ng／mL。将该方法应用于人血清中IgG浓度的测定，取得了满意结果。

An anodic stripping immunoassay based on gold label has been developed. The immunoreaction is performed in a polystyrene microwell using the sandwich format. Rabbit anti-human immunoglobulin G（IgG） antibodies were adsorbed passively on the walls of a polystyrene microwell. The IgG analyte was first captured by the rabbit anti-human antibody and then sandwiched by a colloidal gold-labeled goat anti-human IgG antibody. The subsequent immunocomplex interaction between the colloidal gold-labeled goat anti-human IgG antibody and the colloidal gold-labeled rabbit anti-goat IgG secondary antibody results in the adsorption of a large amount of colloidal gold onto the walls of a polystyrene microwell,which, after gold metal dissolution in an appropriate solution, was determined by anodic stripping voltammetry （ASV） at a carbon-paste 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 IgG concentration over the range of 1. 1 ng/mL to 1 143 ng/mL and a detection limit as low as 1 ng/mL was achieved. The anodic stripping immunoassay was applied to the determination of IgG concentration in human serum with satisfactory results.