SERS/electrochemical dual-mode biosensor based on multi-functionalized molybdenum disulfide nanosheet probes and SERS-active Ag nanorods array electrodes for reliable detection of cancer-related miRNA

The reliable detection of cancer-related biomarkers is essential for accurate diagnosis of cancers. SERS/electrochemical dual-mode sensing can provide a powerful tool to achieve more accurate detection, however, the in situ facile dual-mode detections have rarely been reported. Herein, a novel SERS/electrochemical dual-mode biosensor based on multi-functionalized molybdenum disulfide nanosheet (mF-MoS2 NS) probes and SERSactive Ag nanorods (AgNRs) array electrode was proposed for in situ dual-mode detection of gastric cancerrelated miR-106a. The AgNRs array coated by the mF-MoS2 NSs shows significantly improved electrochemical and SERS stability in electrolyte solutions, and the "mF-MoS2 NSs probes-miRNA-AgNRs array electrodes" sandwich structured SERS/electrochemical sensor was built for stable, in-situ dual-mode detection of miR-106a. The sensor shows good selectivity for differentiating miR-106a from the single-base mismatched nucleic acid, and possesses linear calibration curves of both SERS and electrochemical sensing modes with the limit of detections of 67.44 fM and 248.01 fM, respectively. The reliable assay of miR-106a in human serum indicates that the proposed SERS/electrochemical dual-mode sensor is suitable for detecting complex samples and can be a potential high-sensitive and reliable tool for clinical diagnosis of early cancers.