Type I atelocollagen grafting onto ozone-treated polyurethane films: Cell attachment, proliferation, and collagen synthesis

An approach is presented for the graft copolymerization of type I atelocoll agen onto the surface of polyurethane (PU) films treated with ozone. Throug h inducing oxidization to modify PU surface by ozone, peroxide groups are e asily generated on the surface. Those peroxides are broken by redox-polymer ization, and provide active species which initiate graft polymerization by reacting with amines in the collagen molecules. The ozone oxidation time an d voltage could readily control the amount of peroxide production. The surf ace density of generated peroxides on PU surface was determined by iodide m ethod. The maximum concentration of peroxide was about 10.20 x 10(-8)mol/cm (2) when ozone oxidation was performed at 60 V for 30 min. After the reacti on of PU by ozone oxidation, type I atelocollagen was graft-copolymerized o nto the PU film. All the physical measurements on the collagen-grafted surf ace indicated that the PU surface was effectively covered with type I atelo collagen. The interaction of the collagen-grafted PU surface with fibroblas ts could be greatly enhanced by the surface graft polymerization with type I atelocollagen. Attachment and proliferation of fibroblasts on the grafted type I atelocollagen were significantly enhanced, and it is assumed that t he atelocollagen matrix supported the initial attachment and growth of cell s. In the early stage of proliferation, collagen synthesis in fibroblasts w as not activated and remained at a relatively low level due to the grafted type I atelocollagen, increasing only with fibroblast differentiation. (C) 2000 John Wiley & Sons, Inc.