A new label-free electrochemical immunosensor based on dendritic core-shell AuPd@Au nanocrystals for highly sensitive detection of prostate specific antigen

•Dendritic core-shell AuPd@Au NCs were prepared by a one-pot wet-chemical approach.•Xanthine was used as the green growth-directing agent.•The AuPd@Au NCs served as the carrier and catalyst for PSA and H2O2 reduction, respectively.•The constructed immunosensor showed improved analytical performance for the detection of PSA.

Herein, bimetallic dendritic core-shell AuPd@Au nanocrystals (AuPd@Au NCs) were prepared by a simple one-pot aqueous method using xanthine as a green growth-directing agent. By virtue of the enhanced peak currents in the H2O2 reduction catalyzed by AuPd@Au NCs, a label-free immunosensor was constructed for the detection of prostate specific antigen (PSA). The immunosensor exhibited significantly improved analytical performance for the assay of PSA with wide linear range of 0.1-50 ng mL-1 and low detection limit of 0.078 ng mL-1 (S/N = 3), coupled with the improved stability, reproducibility and selectivity. It provides a promising platform for clinical research and diagnosis.