Synthetic Macrocycle Nanopore for Potassium-Selective Transmembrane Transport
Dan Qiao, Himanshu Joshi, Huangtianzhi Zhu, Fushi Wang, Yang Xu, Jia Gao, Feihe Huang, Aleksei Aksimentiev, Jiandong Feng
Abstract
Reproducing the structure and function of biological membrane channels, synthetic nanopores have been developed for applications in membrane filtration technologies and biomolecular sensing. Stable stand-alone synthetic nanopores have been created from a variety of materials, including peptides, nucleic acids, synthetic polymers, and solid-state membranes. In contrast to biological nanopores, however, furnishing such synthetic nanopores with an atomically defined shape, including deliberate placement of each and every chemical group, remains a major challenge. Here, we introduce a chemosynthetic macromolecule—extended pillararene macrocycle (EPM)—as a chemically defined transmembrane nanopore that exhibits selective transmembrane transport. Our ionic current measurements reveal stable insertion of individual EPM nanopores into a lipid bilayer membrane and remarkable cation type-selective transport, with up to a 21-fold selectivity for potassium over sodium ions. Taken together, direct chemical synthesis offers a path to de novo design of a new class of synthetic nanopores with custom transport functionality imprinted in their atomically defined chemical structure.