A sandwich-type electrochemical immunosensor using trimetallic nanozyme as signal amplification for NT-proBNP sensitive detection

Heart failure (HF) is a major public health problem trigged by a heart circulation disorder. Early detection and diagnosis are conducive to the prevention and treatment of HF. N-terminal B-type natriuretic peptide precursor (NT-proBNP) is considered to be a sensitive diagnostic biomarker of HF. In this study, we constructed a NT-proBNP sandwich electrochemical immunosensor by using electroplated gold nanoparticles (Au NPs) as the substrate and utilizing rough-surfaced trimetallic Au@PdPt nanozymes (Au@PdPt RTNs) as current signal amplification. The Au NPs as substrate material modified glassy carbon electrode (GCE) have excellent conductivity and biocompatibility, which not only accelerate electron transfer rate, but also improve the loading capacity of primary antibody (Ab1). Moreover, the Au@PdPt RTNs were synthesized by a one-pot method and used as the labels to bound with secondary antibodies (Ab2) via the Pt-N. The large specific surface area and excellent catalytic properties for H2O2 of Au@PdPt RTNs can effectively enhance the stability and sensitivity of the immunosensor. With the favorable cooperation of Au NPs and Au@PdPt RTNs, the constructed immunosensor exhibited a wide concentration range from 0.1 pg mL-1 to 100 ng mL-1 and a low detection limit of 0.046 pg mL-1. Furthermore, the accuracy of the analysis of NT-proBNP in diluted human serum samples was satisfactory. The results revealed the electrochemical immunosensor has a prospective application in clinical detection.