Enzyme-free sandwich-type electrochemical immunosensor based on high catalytic binary PdCu mesoporous metal nanoparticles and conductive black phosphorous nanosheets for ultrasensitive detection of pro-SFTPB in non-small cell lung cancer

Abstract

Pro-surfactant protein B (pro-SFTPB) has been proven to be a powerful biomarker for the early diagnosis of non-small-cell lung cancer (NSCLC). In this study, a novel enzyme-free electrochemical immunosensor is developed for the ultrasensitive detection of pro-SFTPB using binary PdCu mesoporous metal nanoparticles (MMNs) and few-layer black phosphorous (BP nanosheets). Concretely, PdCu MMNs, as novel essential signal labels, were successfully synthesized, offering excellent outstanding peroxidase-like catalytic activity toward hydrogen peroxide (H2O2). Meanwhile, the combination of BP nanosheets with biocompatible gold nanoparticles (AuNPs) served as the substrate on the electrode. With the aid of binary PdCu MMNs nanozymes and BP nanosheets, the enzyme-free electrochemical immunosensor revealed ultrasensitivity detection of pro-SFTPB ranging from 10 pg/mL to 100 ng/mL with an ultralow limit of detection of 5.3 pg/mL. In addition, the immunosensor enables accurate detection of pro-SFTPB in serum samples. Altogether, the developed electrochemical immunosensor provides an enzyme-free platform for pro-SFTPB detection, providing a new method for the early diagnosis of NSCLC.