Nanoparticle-blockage-enabled rapid and reversible nanopore gating with tunable memory.

Gated protein channels act as rapid, reversible, and fully-closeable nanoscale valves to gate chemical transport across the cell membrane. Replicating or outperforming such a high-performance gating and valving function in artificial solid-state nanopores is considered an important yet unsolved challenge. Here we report a bioinspired rapid and reversible nanopore gating strategy based on controlled nanoparticle blockage. By using rigid or soft nanoparticles, we respectively achieve a trapping blockage gating mode with volatile memory where gating is realized by electrokinetically trapped nanoparticles near the pore and contact blockage gating modes with nonvolatile memory where gating is realized by a nanoparticle physically blocking the pore. This gating strategy can respond to an external voltage stimulus (∼200 mV) or pressure stimulus (∼1 atm) with response time down to milliseconds. In particular, when 1,2-diphytanoyl-sn-glycero-3-phosphocholine liposomes are used as the nanoparticles, the gating efficiency, defined as the extent of nanopore closing compared to the opening state, can reach 100%. We investigate the mechanisms for this nanoparticle-blockage-enabled nanopore gating and use it to demonstrate repeatable controlled chemical releasing via single nanopores. Because of the exceptional spatial and temporal control offered by this nanopore gating strategy, we expect it to find applications for drug delivery, biotic-abiotic interfacing, and neuromorphic computing.

Protein Analyte Sensing with an Outer Membrane Protein G (OmpG) Nanopore.

Nanopore sensing is a powerful lab-on-a-chip technique that allows for the analysis of biomarkers present in small sample sizes. In general, nanopore clogging and low detection accuracy arise when the sample becomes more and more complex such as in blood or lysate. To address this, we developed an OmpG nanopore that distinguishes among not only different proteins in a mixture but also protein homologs. Here, we describe this OmpG-based nanopore system that specifically analyzes targets biomarkers in complex mixtures.