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利用电沉积纳米金(AuNPs)修饰玻碳电极(GCE)表面并通过AuNPs固定癌胚抗原(CEA)的捕获抗体(Ab1),以牛血清白蛋白(BSA)封闭非特异性吸附位点;以γ-(2,3环氧丙氧)丙基三甲氧基硅烷(GPMS)作交联剂,将单分散的SiO_2纳米粒子与电子媒介体硫堇(Thi)结合成SiO_2-Thi纳米复合物,偶联辣根过氧化物酶(HRP)标记的CEA二抗(HRP-Ab2)作为电化学免疫检测信号,构建了具有信号放大效应的电流型免疫传感器并用于CEA的高灵敏检测。在CEA存在下,进行电化学酶联夹心免疫反应。在含有H2O2的磷酸盐缓冲溶液(PBS)中,标记在SiO_2-Thi纳米复合物上的HRP能催化H_2O_2氧化电子媒介体Thi,产生增强的还原峰电流,从而提高检测CEA的峰电流响应信号,进而实现对CEA的高灵敏电化学酶联夹心免疫分析。在最优实验条件下,该免疫传感器的差分脉冲伏安(DPV)还原峰电流与CEA质量浓度的对数在0.01~20ng/mL范围内呈良好的线性关系,检出限为3pg/mL(S/N=3)。该传感器对血清样品进行加标回收实验,回收率为97.3%~105.7%,可初步用于临床对CEA的检测。
Electrophoretic gold nanoparticles (AuNPs) were used to modify the surface of glassy carbon electrode (GCE), and the capture antibody (Ab1) of carcinoembryonic antigen (CEA) was immobilized by AuNPs. The nonspecific adsorption sites were blocked with bovine serum albumin (BSA) - (2,3-epoxypropyl) propyltrimethoxysilane (GPMS) as crosslinking agent, the monodisperse SiO 2 nanoparticles combined with the electronic mediator Thi (Thi) into SiO 2 -Tii nanocomposites, even The horseradish peroxidase (HRP) -labeled CEA secondary antibody (HRP-Ab2) was used as the electrochemical immunoassay signal to construct a current-type immunosensor with signal amplification effect and used for the highly sensitive detection of CEA. In the presence of CEA, an electrochemical enzyme-linked sandwich immunoreaction was performed. In phosphate buffer solution (PBS) containing H2O2, HRP labeled on SiO_2-Thi nanocomposite can catalyze H_2O_2 to oxidize Thi and produce enhanced reduction peak current to improve the peak current response of detection CEA, And then realize the CEA highly sensitive electrochemical enzyme-linked sandwich immunoassay. Under optimal conditions, the differential pulse voltammetry (DPV) peak current of the immunosensor showed a good linear relationship with the logarithm of CEA mass concentration in the range of 0.01 ~ 20 ng / mL with the detection limit of 3 pg / mL S / N = 3). The sensor for spike recovery test of serum samples, the recovery rate was 97.3% ~ 105.7%, can be initially used for clinical detection of CEA.