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.