Studying Biologically Important Monovalent Cation Diffusion across Lipids Using Molecular Fe Redox Reporters in Hybrid Bilayer Membranes
Year: 2026
Type: preprint
Abstract: We developed a new hybrid bilayer membrane (HBM) platform, Fe(TPY)(CN)3 HBM, incorporating mononuclear Fe complexes chelated by tridentate 2,2':6',2''-terpyridine-4'-oxy-hexane-1-thiol (TPY) ligands and cyanide (CN–) ligands on an Au electrode, forming a stable and robust octahedral complex, covered by a monolayer of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipids, to study the transmembrane diffusion behaviours of monovalent cations, Li+, Na+, K+ and NH4+. The most positive shift in the half-wave potential (E1/2) of Fe3+/2+ redox occurred in presence of Li+, following the descending trend of Li+ > NH4+ > Na+ > K+. On the other hand, the Fe3+/2+ redox exhibited the largest peak separation (ΔE) in presence of Li+, which follows the same descending order. These trends highlight that the transmembrane diffusion mechanism for the monovalent cations studied is governed by interplay of charge density, intermolecular interactions, dehydration energy, and interfacial steric hindrance.
Source: ChemRxiv
Institutions: University of Hong Kong, National Taiwan University
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7204999927