A novel aptameric biosensor based on the self-assembled DNA-WS2 nanosheet architecture.

It has been reported that tungsten disulfide (WS2) can bind single-stranded DNA (ssDNA) with high affinity while it has less affinity toward double stranded DNA (dsDNA). In this work, for the first time, the high affinity between WS2 and ssDNA was used to construct stable sensing interface for ATP detection. A DNA sequence with -SH at one end was first immobilized on Au electrode. WS2 nanosheets were immobilized on the SH-DNA/Au electrode surface due to the strong affinity between WS2 and ssDNA. Then the WS2 nanosheets were used to immobilize ATP binding aptamer (ABA) through the high affinity between WS2 and ssDNA, too. When ATP reacts with the ABA aptamer, duplex will be formed and dissociated from the WS2 nanosheets. On the basis of this, an electrochemical aptasensor for ATP was fabricated. This ATP sensor showed high sensitivity, selectivity and stability due to the unique WS2-ssDNA interactions and the specific aptamer-target recognition. Furthermore, this strategy was generalized to detect Hg2+ using a mercury-specific aptamer (MSO). This strategy can be expected to offer a promising approach for designing high-performance electrochemical aptasensors for a spectrum of targets.