Molecular insights into the adsorption and self-assembly of charged copolypeptides on Silica

Abstract

This study explores the molecular mechanisms driving peptide-silica interactions, focusing on the adsorption and self-assembly of lysine-leucine copolypeptides and their influence on lysozyme adsorption. Using long-timescale molecular dynamics simulations, we examine how charge density and sequence blockiness affect peptide behavior on negatively charged silica surfaces. Poly-lysine homopolypeptides show strong electrostatic interactions, leading to full surface adsorption, while neutral poly-leucine peptides weakly adsorb and orient perpendicularly. Copolypeptides with a fixed charge density of 0.5 exhibit blockiness-dependent adsorption and structural organization. Increased blockiness promotes independent peptide behavior and varied self-assembly. Modified silica surfaces functionalized with these peptides enhance lysozyme stability and reduce conformational disruption compared to bare silica. Our findings demonstrate that peptide sequence design can modulate surface interactions and protein adsorption. This work provides valuable insights into engineering amphiphilic polypeptides for surface functionalization, with potential applications in biomaterials, biosensing, and therapeutic delivery systems.