Gate manipulation of DNA capture into nanopores.

Understanding biophysics governing DNA capture into a nanopore and establishing a manipulation system for the capture process are essential for nanopore-based genome sequencing. In this work, the functionality of extended electric field and electroosmotic flow (EOF) during the capture stage and their dependence on gate voltage, U(G), are investigated. We demonstrate that while both the electric field and EOF within a cis chamber make long-distance contributions to DNA capture around the pore mouth, the former effect is always capturing, while the latter causes trapping or blocking of the molecule depending on the magnitude of the gate voltage, U(G): an anionic EOF induced by high U(G) is capable of doubling the DNA trapping speed and thus the absorption radius in the cis chamber, whereas a cationic EOF by low U(G) would substantially offset the trapping effort by the electric field and even totally block DNA entrance into the pore. Based on the analysis, a gate regulation is proposed with the objective of achieving a high DNA capture rate while maintaining a low error rate.