Photocatalyst mediated FL/PEC dual-mode strategy for microRNAs logic detection based on DSN enzyme assisted amplification strategy.

The abnormal expression of miRNA is closely related to the occurrence and development of cancer and diabetes. There is an urgent need to establish a method for simultaneous detection of multiple miRNAs to ensure the reliability of diagnosis. A dual - mode sensing method was constructed for the simultaneous detection of target miRNA - 21 and miRNA - 155 with an "AND" gating logic strategy, which was achieved by monitoring the changes in Fluorescence/photoelectrochemical (PEC) signals resulting from N3 group conversion. In the absence of target, the Click reaction occurred between N3 and Cu2O/UCNPs (upconversion nanoparticles), inducing G4/Hemin-catalyzed precipitation to reduce the PEC signal. When target miRNA-21 and miRNA-155 are simultaneously inputted, the target mediated cycle amplifications proceed assisted by DSN enzyme and DNAzyme, resulting in capture of liposomes by magnetic beads. CdSe@Au was obtained from the ruptured liposomes and catalyzed the reduction of N3 to generate a fluorescent signal. Meanwhile, the click reaction was inhibited and the biological precipitation was reduced, thereby enhancing PEC signal. This sensor utilized the "AND" gating logic of dual-target inputs and combined the conversion of the N3 group to cause changes in the PEC and FL signals, achieving sensitive detection of miRNAs. When the dual-miRNA was putted with a 1:1 ratio for the concentrations, the limit of detection for FL mode and PEC mode was calculated to be 6.31 fM and 0.25 aM respectively.