Magnetic Platinum-Cobalt Nanoparticles as Peroxidase Mimics for Detection of Cancer Biomarkers

Inorganic nanomaterial-based peroxidase mimics have recently emerged as promising alternatives to natural peroxidases for enhancing the detection sensitivity of bioassays, such as enzyme-linked immunosorbent assay (ELISA). Among them, magnetically active peroxidase mimics are particularly advantageous due to their ability to facilitate efficient separation and enrichment of target analytes. However, most reported magnetic peroxidase mimics suffer from limited catalytic efficiency and stability. In this study, we introduce platinum-cobalt nanoparticles (Pt-Co NPs) as an innovative class of magnetically active peroxidase mimics. These Pt-Co NPs exhibit significantly enhanced catalytic activity and outstanding stability over a wide pH range and at elevated temperatures, outperforming conventional Fe₃O₄-based magnetic peroxidase mimics. Integrated into an ELISA platform, the Pt-Co NPs enabled sensitive detection of two different cancer biomarkers, achieving picogram-per-milliliter detection limits and streamlined assay procedures. The clinical application of the Pt-Co NP-based ELISA was further validated by the successful detection of biomarkers in human serum samples.