Atomistic Characterization of Healthy and Damaged Hair Surfaces: A Molecular Dynamics Study of Fatty Acids on Protein Layer

This study presents an atomistic model of the hair surface using molecular dynamics simulations, focusing on 18-Methyleicosanoic acid (18-MEA) fatty acid chains bonded to keratin-associated protein 10-4 (KAP10-4). The model includes free 18-MEA filling gaps between bound chains, achieving an optimal packing density. The research examines the structural and interaction changes in hair surfaces with varying levels of free and bound 18-MEA, under dry and wet conditions. Findings indicate that depletion of free 18-MEA significantly affects the fatty acid chain properties, while removal of bound 18-MEA impacts water penetration. The study identifies an optimal spacing for replenishing free 18-MEA to restore damaged hair surface properties.