Binding-induced formation of DNAzyme on an Au@Ag nanoparticles/TiO2 nanorods electrode: Stimulating biocatalytic precipitation amplification for plasmonic photoelectrochemical bioanalysis.

Photoelectrochemical (PEC) DNA bioanalysis has been drawing more attention in recent years due to the advantages of PEC technique and the vital importance of DNA biomolecules. DNAzymes are unique catalytic nucleic acid molecules that are capable of catalyzing specific biochemical reactions. Using the target-binding-induced conformation change of hairpin DNA probe to hemin/G-quadruplex-based DNAzyme and a plasmonic Au@Ag nanoparticles (NPs)/TiO2 nanorods (NRs)/fluorine-doped tin oxide (FTO) heterostructured photoelectrode, this work reported a novel and sensitive PEC DNA analysis on the basis of a DNAzyme-stimulated biocatalytic precipitation (BCP) strategy. In such a design, the BCP-induced decrease of plasmonic photocurrent can be related to the target-responsive formation of DNAzymes and thus be monitored to assay the target DNA from 0.1 and 100 nM. In brief, with a plasmonic photoelectrode and a hairpin probe, this work reported a general plasmonic DNAzyme-based PEC DNA analysis, which could also be easily extended to aptasensing toward numerous targets of interest.,Copyright © 2019 Elsevier B.V. All rights reserved.