Gating of Single Synthetic Nanopores by Proton-Driven DNA Molecular Motors

Abstract

Switchable ion channels that are made of membrane proteins play different roles in cellular circuits. Since gating nanopore channels made of proteins can only work in the environment of lipid membrane, they are not fully compatible to the application requirement as a component of those nanodevice systems in which lipid membranes are hard to establish. Here we report a synthetic nanopore-DNA system where single solid-state conical nanopores can be reversibly gated by switching DNA motors immobilized inside the nanopores. High- (on-state) and low- (off-state) conductance states were found within this nanopore-DNA system corresponding to the single-stranded and i-motif structures of the attached DNA motors. The highest gating efficiency indicated as current ratio of on-state versus off-state was found when the length of the attached DNA molecule matched the tip diameter of the nanopore well. This novel nanopore-DNA system, which was gated by collective folding of structured DNA molecules responding to the external stimulus, provided an artificial counterpart of switchable protein-made nanopore channels. The concept of this DNA motor-driven nanopore switch can be used to build novel, biologically inspired nanopore machines with more precisely controlled functions in the near future by replacing the DNA molecules with other functional biomolecules, such as polypeptides or protein enzymes.

Coordination of the electrical and optical signals revealing nanochannels with an ‘onion-like’ gating mechanism and its sensing application

“…[34][35][36] Next, capture probes (4-aminophenylboronic acid (PBA)) are immobilized onto the nanochannel walls via a two-step chemical reaction (Supplementary Figure S2A). After the addition of TPEDB and Glu in the environmental solution, diboronic acids reversibly form stable boronate complexes with cis-diols, resulting in the formation of the oligomers (TPEDB-Glu) n on the channel walls (Supplementary Figure S2B).…”

Surface charge density of the track-etched nanopores in polyethylene terephthalate foils

“…Track-etched nanopores are fabricated by etching the ion tracks inside organic foils, 1 and they gain more and more attention due to their applications in biosensor, 2,3 DNA sequencing, 4,5 mimicking the ion channel, 6,7 and energy conversion. 8 In all these applications, surface charge is crucially important, since it governs ion transport through the pores, especially when the salt concentration is low.…”

Bioinspired Energy Conversion in Nanofluidics: A Paradigm of Material Evolution

“…[17] Furthermore, chemical modification with functional molecules on the inner surface of the asymmetric nanopores endows them with versatile responsiveness and adaptiveness. The transmembrane ionic conductance, as well as the ionic rectifying properties, can be finely modulated in response to changes in the environmental conditions, including pH, [18][19][20][21] temperature, [22,23] light, [24,25] and specific molecular targets, [26,27] which mimics the gating and rectifying functions of biological ion channels. In the past decade, two types of asymmetric ion-transport phenomena have been identified in 1D nanofluidic systems, termed the rectified ionic current and the net diffusion current.…”