Protein adsorption on biomaterial and nanomaterial surfaces: a molecular modeling approach to study non-covalent interactions

Atomistic computer simulations of protein adsorption on the heterogeneous surface of biomaterials and nanomaterials are reviewed. First, we present a very brief introduction to some relevant issues concerning force fields and the computational methodologies currently used, in particular molecular dynamics simulations for studying non-covalent interactions in general. The main results are then discussed, considering the adsorption of different protein subdomains and of whole proteins on different surfaces of an unlike nature. In particular, we review our results for lysozyme and some protein subdomains with a different secondary structure on a strongly hydrophobic graphite surface and on a highly hydrophilic polymeric surface, and preliminary results of protein adsorption on single-walled carbon nanotubes, focusing on the effect of the surface topography and curvature. We also discuss the results obtained in other groups for other proteins or protein subdomains being adsorbed on ceramic materials, either purely ionic (MgO, hydroxyapatite) or covalent (SiO2, taken as a model for mica), and on self-assembled monolayers terminated with various chemical functionalities. The insights gained from these simulations are commented on critically, in particular the use of an implicit solvent or the use of explicit water and the lack of final equilibrium usually achieved in the latter case. Finally, we present some open issues for computer simulations of protein adsorption at an interface, and provide an outlook about possible future work in this area.