DNA Nanostructures for Electrophysiology

Abstract

We report that DNA nanoplates on nanopores in solid-state membranes realize a novel route for macromolecular sensing and sequencing with nanopores [1]. By employing programmable self-assembly with DNA origami, nanoplates are made that are permeable for small ions but by default impermeable for macromolecules such as proteins and DNA. Custom apertures in the center of the nanoplates are shown to enable or inhibit macromolecular translocation in a size- selective fashion. Chemical moieties in the aperture convert the nanoplates into user-definable chemically-selective gatekeepers for nanopores. This is exemplified in experiments with single- stranded bait motifs in the nanoplate aperture that enable the sequence-specific detection of prey DNA molecules by current blockade dwells that are specific to the base-pairing interactions between the bait and prey molecules.Further we created nanometer-scale transmembrane channels in lipid bilayers using self-assembled DNA-based nanostructures [2]. Scaffolded DNA origami was used to create a stem that penetrates and spans a lipid membrane, and a barrel-shaped cap that adheres to the membrane in part via 26 cholesterol moieties. In single-channel electrophysiological measurements, we find similarities to the response of natural ion channels, such as conductances on the order of 1 nS and channel gating. In single-molecule translocation experiments, we highlight one of many potential applications of the synthetic channels, namely as single DNA molecule sensing devices.