Single nucleotide detection using bilayer MoS(2) nanopores with high efficiency

Single nucleotide detection is important for early detection of diseases and for DNA sequencing. Monolayer (ML) MoS(2) nanopores have been used to identify and distinguish single nucleotides with good signal-to-noise ratio in the recent past. Here, we use a bilayer (BL) MoS(2) nanopore (∼1.3 nm thick) to detect distinct single nucleotides with high spatial resolution and longer dwell time. In this study, the performance of similar sized (<3 nm) ML and BL MoS(2) nanopores for detection of a single nucleotide has been compared. Both single nucleotide and single stranded DNA translocations through them are studied. For single nucleotide detection, we observe that BL MoS(2) nanopores demonstrate twice the dwell time as compared to ML MoS(2) nanopores with 95% confidence. Single nucleotide detection rate for BL MoS(2) nanopores (50–60 nucleotides per s) is five-fold higher as compared to ML MoS(2) nanopores (10–15 nucleotides per s) in 10 pM analyte concentration. For single stranded DNA, we observe 89% (for 60 DNA molecules detected) single nucleotide detection efficiency with BL MoS(2) nanopores as compared to 85% for ML MoS(2). The DNA sequencing efficiency through BL MoS(2) nanopores is also found to be 8–10% better than through ML MoS(2) nanopores, irrespective of DNA sequencing orientation. Thus, owing to improved analyte/nanopore charge interaction BL MoS(2) nanopores can be used for single nucleotide detection with high resolution due to longer dwell time, detection rate and efficiency. This study demonstrates the improved ability of BL MoS(2) nanopores in sequencing DNA with 8–10% higher efficiency, two-times temporally resolved single-nucleotide current signatures and five-times higher detection rate, compared to ML MoS(2) nanopores.