Affiliation:
1. Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education, State Key Laboratory of Mechanics and Control for Aerospace Structures, Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics , Nanjing 210016 , China
Abstract
ABSTRACT
Reproducing the outstanding selectivity achieved by biological ion channels in artificial channel systems can revolutionize applications ranging from membrane filtration to single-molecule sensing technologies, but achieving this goal remains a challenge. Herein, inspired by the selectivity filter structure of the KcsA potassium channel, we propose a design of biomimetic potassium nanochannels by functionalizing the wall of carbon nanotubes with an array of arranged carbonyl oxygen atoms. Our extensive molecular dynamics simulations show that the biomimetic nanochannel exhibits a high K+ permeation rate along with a high K+/Na+ selectivity ratio. The free energy calculations suggest that the low Na+ permeability is the result of the higher energy barrier for Na+ than K+ at the channel entrance and ion binding sites. In addition, reducing the number of ion binding sites leads to an increase in the permeation rate but a decrease in selectivity. These findings not only hold promise for the design of high-performance membranes but also help understand the mechanism of selective ion transport in biological ion channels.
Funder
National Natural Science Foundation of China
Natural Science Foundation of Jiangsu Province
National Key Research and Development Program of China
National Key Laboratory of Mechanics and Control for Aerospace Structures
Fundamental Research Funds for the Central Universities
Nanjing University of Aeronautics and Astronautics
Publisher
Oxford University Press (OUP)