Construction of a target-triggered DNAzyme motor for electrochemical detection of multiple DNA glycosylases

Abstract

DNA repair enzymes are responsible for the repair of DNA lesions and are important disease biomarkers. Herein, we construct a target-triggered DNAzyme motor for electrochemical detection of multiple DNA glycosylases based on the DNAzyme motor-driven encoding of different electrochemical molecules. This assay involves two hairpin probes for sensing uracil DNA glycosylase (UDG) and human alkyladenine DNA glycosylase (hAAG), a AuNPs@locked DNAzyme motor which contains the locking strands and the Mg2+/Pb2+ DNAzyme strands, and a magnetic bead track which contains MB/Fc-labelled Mg2+/Pb2+ substrate strands. When UDG and hAAG are present, they can cleave the corresponding hairpin DNA probes to release two single-stranded DNAs (ssDNAs) which can hybridize with the locking strands to induce the liberation of Mg2+/Pb2+ DNAzyme strands from the AuNPs@DNAzyme motor. The subsequent hybridization of Mg2+/Pb2+ DNAzyme strands with their corresponding substrate strands results in the cleavage of Mg2+/Pb2+ substrate strands and the simultaneous release of MB/Fc-labelled ssDNAs from magnetic bead. The released MB/Fc labels can be electrochemically detected for accurate quantification of UDG/hAAG. This target-triggered DNAzyme motor exhibits high sensitivity and good specificity with the capability of simultaneously measuring multiple DNA glycosylases in HeLa cells and screening the potential inhibitors.