An artificial sodium-selective subnanochannel.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36706186.
- Also identified by DOI 10.1126/sciadv.abq1369 and PMC identifier 9882983.
- Licence recorded as CC BY-NC.
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Abstract
Single-ion selectivity with high precision has long been pursued for fundamental bioinspired engineering and applications such as in ion separation and energy conversion. However, it remains a challenge to develop artificial ion channels to achieve single-ion selectivity comparable to their biological analogs, especially for high Na<sup>+</sup>/K<sup>+</sup> selectivity. Here, we report an artificial sodium channel by subnanoconfinement of 4'-aminobenzo-15-crown-5 ethers (15C5s) into ~6-Å-sized metal-organic framework subnanochannel (MOFSNC). The resulting 15C5-MOFSNC shows an unprecedented Na<sup>+</sup>/K<sup>+</sup> selectivity of tens to 10<sup>2</sup> and Na<sup>+</sup>/Li<sup>+</sup> selectivity of 10<sup>3</sup> under multicomponent permeation conditions, comparable to biological sodium channels. A co-ion-responsive single-file transport mechanism in 15C-MOFSNC is proposed for the preferential transport of Na<sup>+</sup> over K<sup>+</sup> due to the synergetic effects of size exclusion, charge selectivity, local hydrophobicity, and preferential binding with functional groups. This study provides an alternative strategy for developing potential single-ion selective channels and membranes for many applications.