Insights from molecular dynamics simulations of albumin adsorption on hydrophilic and hydrophobic surfaces

Protein adsorption at the surface affects the material biocompatibility directly as it is the first reaction that happens when a foreign material comes in contact with blood. In this study, the mechanism of albumin adsorption on hydrophilic and hydrophobic surfaces is investigated. Although it is studied extensively and has been of keen interest for decades, the adsorptive nature of albumin is still not fully understood with contradicting reported studies. This problem results from previous works focusing on mostly qualitative and quantitative adsorption properties of albumin, rather than the specific interaction mechanisms. The variable local surface properties across albumin can significantly impact adsorption and must be explored. In this work, the effect of hydration is found to significantly increase adsorption with minor reductions. The adsorption of albumin on hydrophilic or hydrophobic surfaces is dependent on albumin orientation, which is dictated by local charge effects. Based on these findings, an optimized material surface is proposed to minimize albumin adsorption using functional groups to limit surface availability for hydrophobic interactions while inhibiting excess electrostatic effects at hydrophilic sites. The extent of albumin adsorption and shape change are characterized herein using the heat capacity. Current study identifies interaction mechanisms previously missing in literature, which are responsible for inconsistent adsorption results.