A novel aptamer-functionalized MoS2 nanosheet fluorescent biosensor for sensitive detection of prostate specific antigen

Prostate specific antigen (PSA) is a significant and the most widely used biomarker for the early diagnosis of prostate cancer and its subsequent treatment. A MoS2 nanosheet is a two-dimensional (2D) layered nanomaterial analogous to graphene. However, a MoS2 nanosheet has a higher fluorescence-quenching ability than graphene when applied to a dye-labeled single-stranded DNA probe. In this work, we propose a novel aptamer-functionalized MoS2 nanosheet fluorescent biosensor that detects PSA. The binding of the aptamer to the target PSA induces a rigid aptamer structure which makes the integration with the MoS2 nanosheet very weak. This results in the release of the aptamer probe from the nanosheet surface and restores the quenched fluorescence. This approach has the advantage of simple design and rapid detection of PSA. The biosensor has the merits of high sensitivity and high selectivity with a detection limit for the PSA of 0.2 ng/mL. The biosensor was also successfully applied to the detection of PSA in human serum samples with satisfactory results. The foregoing indicates its promising application to real-life biological samples.