Immobilization of collagen onto polymer surfaces having hydroxyl groups

The cyanogen bromide (CNBr) activation method was adopted to link collagen molecules onto the surface of cellulose and poly(vinyl alcohol) (PVA) films via covalent bonding. The amount of bound protein was determined by the ninhydrin method and found to be 1.0 microgram/cm2 for the native collagen and 0.6 microgram/cm2 for the denatured collagen. The amount of bound protein was larger for cellulose than PVA. When p-toluene-sulphonyl chloride was used to activate the cellulose film, this activation method was found to be effective in grafting the collagen as well. The cellulose film was found to become brittle and weak after activation with CNBr, but the PVA films was not. This might be due to the difference in the extent of crosslinking between cellulose and PVA films, as demonstrated by the change in degree of swelling and solubility of both the activated films.