1.D.225. The Sulfur-containing Foldamer-based artificial Lithium Channel (SF-LCh) Family
Unlike many other biologically relevant ions (Na+, K+, Ca2+, Cl-, etc) and protons, whose cellular concentrations are closely regulated by highly selective channel proteins, Li+ is unusual in that its concentration is well tolerated over many orders of magnitude, and that no lithium-specific channel proteins have so far been identified. While one naturally evolved primary pathway for lithium ions to traverse the cell membrane is through sodium channels by competing with sodium ions, artificial lithium-transporting channels are needed. Shen et al. 2023 showed that sulfur-containing organic nanotubes derived from intramolecularly H-bonded helically folded aromatic foldamers of 3.6 Å in hollow cavity diameter could facilitate highly selective and efficient transmembrane transport of Li+, with high transport selectivity factors of 14.9 and 18.4 over Na+ and K+ ions, respectively.