Abstract

Based on the necessity and urgency of cardiac troponin I (cTnI) detection for the diagnosis of myocardial infarction, a novel unlabeled photoelectrochemical (PEC) immunosensor has been developed to detect cTnI rapidly and sensitively. Silicon nanowire arrays (SiNWs) were prepared via metal-assisted chemical etching. To improve the stability and sensitivity towards cTnI sensing, the surface of silicon nanowire arrays were coated with polydopamine by an in situ growth method. PDA was uniformly modified on the nanowire surface to provide a reliable active site for antibody binding. The linear dynamic range of the cTnI detection method was 0.005–10 ng mL−1, and the detection limit was 1.47 pg mL−1. The designed PEC immunosensor exhibited good sensitivity, selectivity, stability and reproducibility. The electrode enabled label-free detection and provided a new route to realize point-of-care testing of cTnI.