PHYSICAL CROSS-LINKING OF COLLAGEN-FIBERS - COMPARISON OF ULTRAVIOLET-IRRADIATION AND DEHYDROTHERMAL TREATMENT

The strength, resorption rate, and biocompatibility of collagenous bio materials are profoundly influenced by the method and extent of crossl inking. We compared the effects of two physical crosslinking methods, ultraviolet irradiation (UV) (254 nm) and dehydrothermal (DHT) treatme nt, on the mechanical properties and molecular integrity of collagen f ibers extruded from an acidic dispersion of type I bovine dermal colla gen. Collagen fibers exposed to UV irradiation for 15 min had ultimate tensile strength (54 MPa) and modulus (184 MPa) values greater than o r equivalent to values for fibers crosslinked with DHT treatment for 3 or 5 days. UV irradiation is a rapid and easily controlled means of i ncreasing the mechanical strength of collagen fibers. Characterization of collagen extracted from the crosslinked samples by dilute acetic a cid and limited pepsin digestion indicate that both UV and DHT treatme nts cause fragmentation of at least a portion of the collagen molecule s. Partial loss of the native collagen structure may influence attachm ent, migration, and proliferation of cells on collagen fiber-based lig ament analogs. These issues are currently being addressed in our labor atory. (C) 1995 John Wiley & Sons, Inc.