Low Noise Hybrid Nanopore with Engineered OmpG and Bilayer MoS₂

Hybrid nanopores combine the durability of a solid-state nanopore with the precise structure of a biological nanopore. When a DNA strand is pulled electrophoretically through a solid-state nanopore it can be sensed using the ionic blockade current produced by each translocating molecule. However, owing to the lack of chemical specificity and pore size reproducibility, solid-state nanopore sensing suffers from poor repeatability. Biological nanopores which have a constant geometry ensure sensitive and repeatable sensing. In this study, hybrid nanopores were formed by insertion of a engineered outer membrane porin G (eOmpG) in a bilayer (BL) molybdenum disulfide (MoS₂) solid-state nanopore. Engineered outer membrane porin G (eOmpG) is used as the biological counterpart of the hybrid nanopore due to its uniform cylindrical geometry and controlled gating useful for specific detection of label-free analytes. BL MoS₂ is used as the solid-state support for the hybrid construct owing to its surface charge and 2D layered properties, which ensures a stable support with low capacitive noise, favorable for precise sensing. To realize the hybried nanopore a single eOmpG was electrophoretically pulled through a 3.4 nm BL MoS₂ solid-state nanopore at neutral pH and +80 mV trans bias. A hybrid BL MoS₂-eOmpG nanopore was found to demonstrate 32% lower noise levels with nearly 1.9 times improved in the signal-to-noise ratio (SNR) and 6.5 times longer dwell times for dA30 molecular sensing compared to the BL MoS₂ solid-state nanopore. Thus, the low-noise biocompatible platform of the hybrid BL MoS₂-eOmpG nanopore can be used for highly resolved biomolecular sensing.