Optimal transport and colossal ionic mechano-conductance in graphene crown ethers

Abstract

Biological ion channels balance electrostatic and dehydration effects to yield large ion selectivities alongside high transport rates. These macromolecular systems are often interrogated through point mutations of their pore domain, limiting the scope of mechanistic studies. In contrast, we demonstrate that graphene crown ether pores afford a simple platform to directly investigate optimal ion transport conditions, i.e., maximum current densities and selectivity. Crown ethers are known for selective ion adsorption. When embedded in graphene, however, transport rates lie below the drift-diffusion limit. We show that small pore strains -- 1 % -- give rise to a colossal -- 100 % -- change in conductance. This process is electromechanically tunable, with optimal transport in a primarily diffusive regime, tending toward barrierless transport, as opposed to a knock-on mechanism. Measurements of mechanical current modulation will yield direct information on the local electrostatic conditions of the pore. These observations suggest a novel setup for nanofluidic devices while giving insight into the physical foundation of evolutionarily--optimized ion transport in biological pores.

References in corpus (10)

• Electric Field Effect in Atomically Thin Carbon Films
• Precise and ultrafast molecular sieving through graphene oxide membranes
• Graphene-Wrapped Sulfur Particles as a Rechargeable Lithium-Sulfur-Battery Cathode Material with High Capacity and Cycling Stability
• A tight-binding approach to uniaxial strain in graphene
• Anomalously low dielectric constant of confined water
• Dehydration as a Universal Mechanism for Ion Selectivity in Graphene and Other Atomically Thin Pores
• Aqueous ion trapping and transport in graphene-embedded 18-crown-6 ether pores
• Ionic selectivity and filtration from fragmented dehydration in multilayer graphene nanopores
• Maxwell-Hall access resistance in graphene nanopores
• Golden aspect ratio for ion transport simulation in nanopores

Cited by in corpus (5)

• Colloquium: Ionic phenomena in nanoscale pores through 2D materials
• Pressure Induced Enlargement and Ionic Current Rectification in Symmetric Nanopores
• Ion transport across solid-state ion channels perturbed by directed strain
• Diffusion Limitations and Translocation Barriers in Atomically Thin Biomimetic Pores
• Entropic modulation of divalent cation transport