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  

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

作　　者：文茜[1] 黄勇[1] 蒋健晖[1] 沈国励[1] 俞汝勤[1] 

机构地区：[1]湖南大学化学化工学院化学生物传感与计量学国家重点实验室

出　　处：《化学学报》2008年第3期343-348,共6页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos. 20435010, 20575020);教育部(No. NCET-04-0768)资助项目

摘　　要：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人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形成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,后者在纳米金的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[V(HNO3)∶V(HCl)=1∶3]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100ng/mL～2μg/mL及100pg/mL～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.A novel sensitive electrochemical immunoassay method was proposed based 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 （h IgG） as the analyte, h IgG was firstly captured by primary goat anti-h IgG polyclonal antibody （h IgG Ab） immobilized on polystyrene microwells. Gold nanopartcile-labeled alkaline phosphatase （ALP）-h IgG Ab was then bound to the microwells through sandwiched h IgG. 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 deposited metal was released in aqua regia （[V（HNO3） ： V（HCl） = 1：3]）, 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 h IgG concentration over the range from 100 ng/mL to 2μg/mL and from 100 pg/mL to 100 ng/mL respectively, and the detection limit was 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-h IgG Ab.

关 键 词：生物沉积 纳米金 电化学免疫分析 催化氢还原 

分 类 号：O657.1[理学—分析化学]