Recapturing and trapping single molecules with a solid-state nanopore

Abstract

The development of solid state nanopores, inspired by their biological counterparts, shows great potential for the study of single macromolecules. Applications such as DNA sequencing and exploration of protein folding will require understanding and control of the dynamics of a molecule’s interaction with the pore, but DNA capture by a solid state nanopore is not well understood. By recapturing individual molecules soon after they pass through a nanopore, we reveal the mechanism by which double stranded DNA enters the pore. Observed recapture rates and times agree with solutions of a drift-diffusion model. Electric forces draw DNA to the pore over micron distances, and, upon arrival at the pore, molecules begin translocation almost immediately. Repeated translocation of the same molecule improves measurement accuracy, offers a way to probe chemical transformations and internal dynamics of macromolecules on sub-millisecond time and sub-micron length scales, and demonstrates the ability to trap, study, and manipulate individual macromolecules in solution.