一种基于纳米金介导生物沉积铂催化氢还原的电化学免疫分析新方法

本文发展了一种基于纳米金介导生物沉积铂并以铂催化氢还原伏安法进行检测的高灵敏电化学免疫分析新方法。该方法采用夹心免疫分析模式，实现了人免疫球蛋白（HIgG）的测定。首先在聚苯乙烯微孔板中固定羊抗HIgG捕获抗体，HIgG捕获后，碱性磷酸酶标记的HIgG抗体修饰的纳米金探针通过与HIgG的形成的夹心复合物而结合在微孔板上。结合的碱性磷酸酶催化抗坏血酸磷酸酯底物水解产生抗坏血酸，后者在纳米金上介导下还原铂离子沉积于纳米金表面。沉积的金属铂用王水溶解并电富集于玻碳电极上。通过测定铂催化氢还原产生的阴极电流，可实现HIgG的高灵敏分析。催化氢还原电流与HIgG浓度对数在0.1~100ng/ml之间呈线性相关性，检测限达22pg/ml。由于铂催化氢还原的高灵敏度及纳米金介导的生物沉积放大反应，该法具有较高的分析灵敏度，且免疫分析微孔板模式使得该法可同时用于大量样品的分析。

Gold Nanoparticle-Mediated Biocatalytic Deposition of Platinum with Catalytic Hydrogen Electrochemical Determination for Highly Sensitive Immunoassay

A novel sensitive electrochemical immunoassay method was proposed base on gold nanoparticle mediated biocatalytic deposition of platinum followed by stripping voltammetric determination. The feasibility of the approach was investigated using a “sandwich” immunoassay format with human immunoglobulin G (HIgG) as the analyte. HIgG was firstly captured by primary goat anti-HIgG polyclonal antibody (HIgG Ab) immobilized on polystyrene microwells. Gold nanopartcile-labeled alkaline phosphatase (ALP)-HIgG Ab was then bound to the microwells through sandwiched HIgG. The surface-bound alkaline phosphate catalyzed the generation of ascorbic acid, which, in turn, reduced platinum ions into its metal form in the presence of gold nanoparticles. The depositedmetal was released in aqua regia (three parts HCl, one part HNO3), and reduced on glassy-carbon electrode, which generated a significant cathodic current due to the platinum-catalyzed hydrogen evolution. The cathodic current was observed to show linear correlation to logarithmic HIgG concentration over the range from 0.1ng/ml to 100ng/ml with a detection limit as low as 22 pg/ml. The high performance of the method is attributed to the sensitive determination of platinum and the catalytic precipitation-based amplification mediated by gold nanopartcile-labeled ALP-HIgG Ab.