An enzyme-free electrochemical biosensor based on NiCoP@PtCu nanozyme and multi-MNAzyme junctions for ultrasensitive Uracil-DNA glycosylase detection

Abstract

Abnormal expressions of uracil-DNA glycosylase (UDG) have been associated with various diseases. We proposed a novel electrochemical biosensing platform-based strategy for UDG detection. This method combined NiCoP@PtCu nanozyme with multi-MNAzyme junctions. The U base was deleted in the presence of UDG, resulting in self-assembly of multi-MNAzyme junctions with the ability to continually cleave DNA hairpins and release various products. The products could bind the protective probes, exposing capture probes on the electrode’s surface. Moreover, the exposed probes hybridized with the sDNAs-labeled NiCoP@PtCu nanozyme, yielding a significant electrochemical signal. The established biosensor was enzyme-free and with an ultrahigh sensitivity. Benefiting from the twofold amplification of multi-MNAzyme junctions and nanozyme, the sensing technique exhibited a large dynamic range, from 0.001 to 1.0 U mL −1 and a low detection of 6.6 × 10−4 U mL −1. In addition, the method was effectively used for UDG detection in lysed cells. Therefore, the biosensor we established has broad prospects in clinical diagnosis and biomedical research.