Ultrasensitive photoelectrochemical detection of cancer-related miRNA-141 by carrier recombination inhibition in hierarchical Ti3C2@ReS2

•A novel PEC biosensor based on Ti3C2@ReS2 Schottky junction was fabricated.•A linear detection window for miR-141 was achieved from 10−16 M to 10-9 M with a limit of 2.4 Am.•Related mechanism for its ultrasensitive detection of miRNA-141 was suggested. Elucidation of the photoelectrochemical (PEC) detection mechanism and exploring highly efficient photoactive materials hold both a challenge and an opportunity to construct high-performance biosensors. In this work, we present a strategy to enhance the charge separation efficiency by fabricating hierarchical Ti3C2@ReS2 via the vertical anchoring flaky ReS2 on the Ti3C2 backbone. According to the experimental results, the Ti3C2@ReS2 sample containing 45 wt % of ReS2 exhibits a 2.48-time promotion in the photocurrent as compared to ReS2 owing to the synergistic effects of its photoactive and conductive counterparts, indicating its significant advantages in separating photo-induced carriers and suppressing carrier recombination. In essence, the Ti3C2@ReS2 Schottky junction formed at the interface can capture the photogenerated electrons generated by ReS2, thereby suppressing carrier recombination. As a result, an ultrasensitive PEC detection platform based on the optimized Ti3C2@ReS2 can offer a log-linear detection window from 0.1 fM to 1 nM with an estimated detection limit of 2.4 aM (S/N = 3) for cancer-related miRNA-141 without any other amplification.