Protein adsorption on tethered polymer layers: effect of polymer chain architecture and composition

The ability of tethered polymer layers to modify the adsorption behavior of simple model proteins is studied using single-chain mean-field theory. Several different polymer molecular structures are considered. It is found that branched polymer chains are much more effective in preventing protein adsorption than linear flexible chains. Diblock copolymers formed by a flexible and a rigid block show similar steric repulsion than fully flexible chains of the same number of monomers. However, the distribution of free ends is very different for the two types of molecules. Polymers with the two ends tethered at surfaces are more efficient than chains with one end on the surface with the same molecular weight to prevent protein adsorption. Mixtures of polymer chains at the surface show an ability to prevent protein adsorption that is different from a linear combination of the pure component polymer layers. The effect of attractive interactions between the protein and the segments of the tethered polymer chains is studied. The effective interaction between the protein and the polymer layer shows an attractive part for proteins that are at the tip of the polymer layer in qualitative agreement with recent experimental observations.