Surface-Functionalized MoS2 Nanosheets Sensor for Direct Electrochemical Detection of PIK3CA Gene Related to Lung Cancer

An electrochemical biosensor for direct detection of PIK3CA gene related to lung cancer was developed based on riboflavin 5'-monophosphate sodium salt (FMNs)-functionalized MoS2 nanosheets prepared by simple ultrasonication method. As a highly effective biodispersant, FMNs demonstrated excellent stabilization for obtaining highly dispersed MoS2 nanosheets in an aqueous solution. The prepared FMNs/MoS2 nanocomposite with fine electrochemical redox activity was employed as the platform to immobilize DNA probe and supplied the inherent indicator signal for DNA sensing. The amine-terminated ssDNA probe was covalently immobilized onto the FMNs/MoS2 nanocomposite with rich phosphonate groups. After the hybridization of the probe ssDNA with the complementary target DNA, the self-redox signal of the nanocomposite decreased ascribed to the changes in the conformation of DNA. The results indicated that the proposed self-signal detection platform displayed high sensitivity with a detection limit of 1.2 × 10–17 mol l−1 for PIK3CA gene from lung cancer, accompanied with fine selectivity, outstanding stability and reproducibility. The constructed biosensor was easy to design and had the potential for the detection of different pathogenic DNA without intricate label process.