PROTEIN ADSORPTION ON TETHERED POLYMER LAYERS - EFFECT OF POLYMER-CHAIN ARCHITECTURE AND COMPOSITION

The ability of tethered polymer layers to modify the adsorption behavi or of simple model proteins is studied using single-chain mean-field t heory. Several different polymer molecular structures are considered, It is found that branched polymer chains are much more effective in pr eventing protein adsorption than linear flexible chains. Diblock copol ymers formed by a flexible and a rigid block show similar steric repul sion than fully flexible chains of the same number of monomers. Howeve r, the distribution of free ends is very different for the two types o f molecules. Polymers with the two ends tethered at surfaces are more efficient than chains with one end on the surface with the same molecu lar weight to prevent protein adsorption. Mixtures of polymer chains a t the surface show an ability to prevent protein adsorption that is di fferent from a linear combination of the pure component polymer layers . The effect of attractive interactions between the protein and the se gments of the tethered polymer chains is studied. The effective intera ction between the protein and the polymer layer shows an attractive pa rt for proteins that are at the tip of the polymer layer in qualitativ e agreement with recent experimental observations.