基于双重信号放大的电化学免疫法对前列腺特异性抗原的检测

以谷胱甘肽修饰的CdTe量子点(GSH-CdTe QDs)与金纳米粒(AuNPs)形成复合材料(AuNPs@GSH-CdTe)为信号标记物，并在还原氧化石墨烯(rGO)和AuNPs双重信号放大的作用下，建立了一种高灵敏检测前列腺特异性抗原(PSA)的三明治免疫夹心式电化学方法。在rGO/AuNPs表面固定二抗蛋白(Ab₂)，捕获目标物PSA和标记有一抗蛋白(Ab₁)的AuNPs@GSH-CdTe信号物，形成“三明治”免疫夹心结构。经HNO₃溶解后，采用方波溶出伏安法(SWSV)测定酸解的Cd²⁺的峰电流用于定量分析PSA。其中AuNPs较大的比表面积以及较好的生物相容能力，达到了成功装载抗体以及放大信号的效果，同时具有较大表面积的rGO起到了协同放大的作用。所构建的免疫分析方法实现了对肿瘤标志物PSA的检测，其线性范围为0.5~200 ng/mL，检测限为5.0 pg/mL，并且该方法专属性、重复性以及稳定性好。此外，在实际样品的检测中，加标样回收率为98.20%~106.2%，结果准确度良好，为检测PSA提供了准确可靠且灵敏度高的新方法。

Detection of prostate specific antigen-based on dual signal amplified electrochemical immunoassay

A sandwiched electrochemical immunoassay based on the AuNPs@GSH-CdTe as a signal label, which formed by GSH-CdTe QDs and AuNPs, with dual signal amplified by reduced graphene oxide and AuNPs was proposed for the sensitive detection of prostate specific antigen(PSA). Through a sandwich immunoreaction, the target PSA and AuNPs@GSH-CdTe labeled Ab₁ were captured to rGO/AuNPs-Ab₂ surface. After the HNO₃-dissolution step, square wave stripping voltammetry(SWSV)analysis of the captured CdTe QDs was used to quantify the concentration of PSA. In this system, AuNPs possessedlarge specific surface and good biocompatibility, which could effectively expand the amount of antigen and GSH-CdTe QDs loading and signals amplifying, while rGO played a synergistic amplification role due to its large specific surface. The proposed method showed good linearity ranging from 0. 5 to 200 ng/mL with the detection limits of 5. 0 pg/mL. It also showed excellent selectivity, good reproducibility, satisfactory stability. In addition, the method was successfully applied to the determination of real samples. The result was satisfactory and the recovery could fall in 98. 20%- 106. 2%, which represented a novel approach for versatile detection of tumor markers.