Deciphering amino acid adsorption on PVC surface: insights from molecular dynamics and PMF calculations

Biofouling is a key process affecting the biocompatibility of biomaterial surfaces such as polyvinyl chloride (PVC). Investigating the physicochemical aspects of this process requires delving into the amino acid level to identify the interactions between proteins and biomaterials. In this computational study, we performed triplicate 50 ns molecular dynamics (MD) simulations along with potential of mean force (PMF) calculations to investigate the adsorption of the 20 standard amino acids on a PVC surface (171 chains, 35-mer each) at a constant concentration and neutral pH. Simulation results show that among the 20 amino acids, tryptophan exhibits the strongest affinity for PVC in terms of adsorption amount and interaction energy (-18.6 kJ mol-1). Moreover, hydrophobic interactions are the main driving force for the adsorption of amino acids onto the PVC surface, and there is a linear correlation between volume and adsorption energetics in each group of amino acids. Valine was the only exception to this trend; however, the increased energy value of valine within its class (-12.8 kJ mol-1) can be explained by its higher polarity. We further analyzed the correlation between intrinsic properties and the chemical nature of amino acids and their respective adsorption energetics. By performing structure-activity relationships, we identified the importance of hydrophobicity, aromaticity, size, and specific functional groups in their adsorption affinity towards PVC surfaces. We also identified the specific parameters contributing to the adsorption behavior of different classes of amino acids. The results of this study have direct implications for biofouling in medical devices, where PVC surfaces are commonly employed. Furthermore, these insights can potentially guide the medical device industry to develop materials with enhanced biocompatibility tailored for specific biomolecular interactions. Molecular dynamics simulations of adsorption of amino acids on PVC surface.