Investigating structural stability of transmembrane Ligand-Appended Pillar[n]ene (LAP)

Artificial water channels are synthetic, transmembrane molecules inspired by aquaporins and offer a scalable solution for biological membrane applications. Matching the high-water permeability of the aquaporin channel while presenting a self-assembly structure that leads to properly aligned channels, ligand-appended pillar[n]ene (LAP) is a promising candidate for forward water treatment membranes. However, due to the variety of chemistries that can be appended the pillar[n]ene ring structure, the stability and selectivity of this channel are not yet fully characterized. Through atomistic molecular dynamics, we correlate the stability, permeability, and selectivity of appended peptides on the pillar[5,6]ene structures to guide experimental design and identify structural motifs that benefit water-ion selectivity and single-file water permeation. Our findings show a favorable parameter space for both channel structures and investigate the free-energy profile for ion, water, and channel insertion.