Catalytic hairpin assembly-mediated Cu2O nanocubes as the competitive dual-quenching tags for photoelectrochemical bioassay of miR-141

Abstract

MicroRNAs (miR) as newly identified biomarkers are closely associated with various cancers, and sensitive monitoring of abnormal miR is great importance in cancer diagnosis. In this work, a novel photoelectrochemical biosensor was developed to sensitively detect miR-141 by the competitive dual-quenching of catalytic hairpin assembly (CHA)-dependent Cu2O nanocubes (NCs) toward β-CD-functionalized CdS nanorods (β-CD@CdS NRs). The biosensing platform was constructed by the stepwise assembly of β-CD@CdS NRs and adamantane-labeled hairpin DNA probe 1 on ITO electrode. In the presence of miR-141, CHA recycling was triggered to immobilize the capture DNA-labeled Cu2O NCs with the aid of hairpin DNA probe 2. The assembly of Cu2O NCs could largely reduce the photocurrent response of CdS NRs based on the competitive consumption of light energy and electron donor. The designed biosensor showed a wide linear range (1.0 pM–100 nM) and a detection limit of 0.47 pM, as well as excellent selectivity and satisfactory stability. Based on the above outcomes, the proposed biosensing device was also applied to miR-141 analysis in human serum with the recoveries ranging from 95.9 % to 104.7 %, achieving a great prospect in clinical application.