免疫纳米金共振散射光谱探针检测痕量免疫球蛋白A

将纳米金的共振散射效应和纳米金标记免疫反应结合起来建立了一种测定免疫球蛋白A的新方法. 采用柠檬酸三钠改良法制备了粒径约为10 nm的纳米金, 用于标记羊抗人免疫球蛋白A获得了免疫球蛋白A (IgA)的免疫共振散射光谱探针. 在pH 5.6的Na₂HPO₄-C₆H₈O₇缓冲溶液和PEG 6000存在下, 金标羊抗人免疫球蛋白A与IgA产生特异性结合, 引起金纳米粒子聚集, 导致金纳米粒子580 nm处的共振散射峰增强. 对免疫分析的条件进行了优化, IgA浓度在0.0054～1.35 μg•mL^－1范围内与580 nm处的共振散射强度呈线性关系, 方法的检测限(3σ)为2.0 ng•mL^－1, 相关系数为0.9983. 用于定量分析人血清中的免疫球蛋白A, 结果满意.

Immunonanogold Resonance Scattering Spectral Probe for Assay of Trace IgA

An immunoassay has been developed for IgA, based on nanogold resonance scattering effect and nanogold labeling. Nanogold in size of 10 nm was prepared by a trisodium citrate method and used to label goat anti-human IgA to obtain an immunoresonance scattering spectral probe for IgA. The immunoreaction between nanogold-labeled antibodies and antigens took place in pH 5.6 Na₂HPO₄-C₆H₈O₇ buffer solution in the presence of PEG 6000 that resulted in the aggregation of the nanogold, and the great linear intensity enhancement of resonance scattering peaks at 580 nm. The assay conditions were considered and optimized. The enhanced intensity ΔI_RS is proportional to the concentrations in the range of 0.0054～1.35 μg•mL^－1 IgA, with a detection limit of 2.0 ng•mL^－1. The method was applied to quantitative determination of IgA in human serum, with satisfactory results.