INFLUENCE OF ETHYLENE-OXIDE GAS TREATMENT ON THE IN-VITRO DEGRADATIONBEHAVIOR OF DERMAL SHEEP COLLAGEN

The influence of ethylene oxide gas treatment on the in vitro degradat ion behavior of noncrosslinked, glutaraldehyde crosslinked or hexameth ylene diisocyanate crosslinked dermal sheep collagen (DSC) using bacte rial collagenase is described. The results obtained were compared with the degradation behavior of either nonsterilized or gamma-sterilized DSC. Upon ethylene oxide sterilization, reaction of ethylene oxide wit h the free amine groups of DSC occurred, which resulted in a decreased helix stability, as indicated by a lowering of the shrinkage temperat ure of all three types of DSC. Except for the low strain modulus the m echanical properties of the ethylene oxide sterilized materials were n ot significantly altered. gamma-Sterilization induced chain scission i n all three types of DSC, resulting in a decrease of both the tensile strength and the high strain modulus of noncrosslinked and crosslinked DSC. When exposed to a solution of bacterial collagenase, ethylene ox ide sterilized materials had a lower rate of degradation compared with nonsterilized DSC. This has been explained by a reduced adsorption of the collagenase onto the collagen matrix as a result of the introduct ion of pendant N-2-hydroxy ethyl groups. (C) 1995 John Wiley and Sons, Inc.