Sensitive Electrochemiluminescence Immunosensor for Determination of Tumor Biomarker PSA Based on Multifunctionalized Pt/Ag@BSA Core–Shell Nanoparticles

Abstract

A multifunctionalized bovine serum albumin encapsulated platinum and silver alloys core–shell nanoparticles (Pt/Ag@BSA NPs)‐based electrochemiluminescence (ECL) immunosensor for ultrasensitive determination of tumor marker prostate‐specific antigen (PSA) has been designed. In this work, Pt/Ag@BSA core–shell nanoparticles with large surface area, favorable electrical conductivity, and biocompatibility were employed as ideal multifunctional carriers to effectively immobilize numerous luminol molecules and PSA capture antibodies (Anti‐PSA) acted as signal probe and molecule recognition probe, respectively. In addition, AuNPs were electrodeposited onto the indium tin oxide (ITO) to construct an outstanding base for this immunosensor, which could promote the electron transfer and load a large amount of multifunctionalized Pt/Ag@BSA nanoparticles. The constructed immunosensor could specifically capture PSA, which hindered the electron transfer of the ECL reaction between luminol and H2O2 because of the barrier of the attached immunoprotein layer and thereby resulted in the decrease of ECL intensity. Under the optimal conditions, ECL intensity of the immunosensor decreased linearly with the logarithm of PSA concentration ranging from 0.001 to 200 ng/mL with a low detection limit of 0.0003 ng/mL (S/N = 3). The proposed immunosensor exhibited high performances in sensitivity, reproducibility, stability, and specificity. Furthermore, the developed immunoassay has been applied to the detection of PSA in real serum samples with satisfactory results.