Probing the Adsorption of Fibronectin onto Model Biomaterial Surfaces using Molecular Dynamics Simulations

Fibronectin is a versatile extracellular matrix glycoprotein, which fulfils many roles in cell adhesion and growth. Adsorption of fibronectin on biomaterial surfaces can influence the eventual biological fate of implanted medical devices or be used in to modify the biological activity of surfaces. Understanding the behaviour of fibronectin on surfaces relies on knowledge of its conformation and orientation of fibronectin and how this is affected by surface chemistry. Using atomistic molecular dynamics simulations, the behaviour of type-III fibronectin fragments, containing heparin binding sites, is investigated on models of biomaterial surfaces. Stronger adsorption is seen on the more hydrophobic ethyl acrylate terminated surface compared to a surface terminated with methyl acrylate groups. This shows that minor changes to the surface chemistry can lead to significant changes to protein behaviour, with the removal of a methyl group from the surface significantly reducing the tendency for protein adsorption. Even for the more hydrophobic surface, polar and charged residues were involved in surface adsorption, potentially due to favourable interactions with acrylate groups in the surface. This new information may be used to improve the design of biomaterials with tailored interactions with proteins.