Entropy-Stabilized Redox Synergy in Hollow High-Entropy Alloy Nanorods for Label-Free Electrochemical Immunosensing of Cancer Biomarker

Early liver cancer diagnosis requires detecting tumor biomarkers at ultralow concentrations. Conventional methods lack sufficient sensitivity for liver cancer biomarker PIVKA-II in early-stage disease. This study addressed this issue by developing an electrochemical immunosensor based on hollow TePtIrFeCo high-entropy alloy (HEA) nanorods (HEANRs), which were synthesized by a coreduction method. The hollow architecture provided abundant active sites for the antibody immobilization and signal amplification. By leveraging the entropy-stabilized redox synergy effect, the biosensor exhibited a wide linear range from 0.1 to 1,000,000 pg mL –1 and an ultralow detection limit (0.02 pg mL –1 ) for PIVKA-II. Biosample analysis shows good accordance with standard ELISA, validating the reliability. This platform establishes HEA as high-performance material for label-free immunosensing of biomarkers in early cancer diagnosis.