A sensitive immunosensor for detection of tumor biomarker based on bimetallic Cu-Zn oxide nanoparticles

The current study was carried out to construct a novel colorimetric sandwich immunosensor for the sensitive, accurate, and rapid detection of prostate-specific antigen (PSA), a critical tumor biomarker for the diagnosis and screening of prostate cancer. The colorimetric sandwich immunosensor was an act-based mixture of a bimetallic Zn-Cu oxide nanoparticles (NPs) and a magnetic bead (MB) in a chromogenic reaction. The capture antibody was covalently immobilized on a carboxylated magnetic beads (MBs) surface to create the colorimetric sandwich immunosensor. Zn-Cu oxide NPs probes functionalized with signal antibodies were used to create an immunocomplex following PSA immunorecognition. The immunosensor exhibited superior catalytic activity with a wide linear range of 10−3-103 ng/mL, a low limit of detection of 8 pg/mL, high reproducibility with a relative standard deviation (RSD) of 4.17 %, excellent repeatability over 10 consecutive measurements, strong stability retaining 96.08 % of its initial response after 25 days of storage, and great accuracy and validity for application in biological samples. The immunosensor showed outstanding specificity with minimal interference from other cancer biomarkers and proteins. This simple, cost-effective, and rapid method holds substantial potential for point-of-care diagnostics and improved prostate cancer monitoring.