Ultrasensitive label-free electrochemical immunosensor of NT-proBNP biomarker based on branched AuPd nanocrystals/N-doped honeycombed porous carbon.

N-terminal pro-B-type natriuretic peptide is a major cardiac biomarker for early diagnosis and prognosis of heart failure. Herein, a novel label-free electrochemical immunosensor was developed based on home-made branched AuPd nanocrystals/N-doped porous carbon (AuPd NCS/NPC) for ultrasensitive and high-selective detection of N-terminal pro-B-type natriuretic peptide. Specifically, the AuPd NCS/NPC was prepared by a one-pot wet-chemical strategy by using thymine as a green structural directing agent, whose morphology, structures, and properties were strictly examined, showing high-efficiency catalysis towards electro-reduction of hydrogen peroxide. Under the optimized conditions, the fabricated sensor exhibited a dynamic linear range of 0.001 ∼ 10 ng mL and a low limit of detection (0.34 pg mL, S/N = 3) for immunoassay of N-terminal pro-B-type natriuretic peptide. Furthermore, this platform was explored for detection of the biomarker in human serum sample with satisfactory results. Thus, the built biosensor can render valuable guidance for prospective clinical diagnostic applications.