BACKGROUND: Collagen materials have good biocompatibility and biodegradability, but also had some problems such as low mechanical strength, poor resistance to degradation exposed in the process of clinical application. Numerous studies have reported that proper crosslinking could improve the disadvantage of collagen materials, regulate porous network structure, swelling and degradation of collagen materials.
OBJECTIVE: To optimize carbodiimide crosslinking process of collagen sponge and determine the best process conditions.
METHODS: Collagen sponge was cross-linked by carbodiimide for the preparation of loose and porous collagen sponge. Meanwhile, we optimized the conditions of cross-linking, in which the selected concentration of carbodiimide was 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 mmol/L, linking time was 2, 4, 6, 8, 12, 16, 20, 24 hours, and linking temperature was 5, 10, 15, 20, 25, 30, 35 ℃. We evaluated the best process conditions of collagen sponge through the aperture, porosity, water absorption, and degradation rate.
RESULTS AND CONCLUSION: The optimal conditions were carbodiimide concentration 50 mmol/L, crosslinking temperature 20 ℃, crosslinking time 6 hours. At this point, the average pore diameter of collagen sponge was 105 μm, the porosity was 79.45%, water absorption was 287.14%, and the degradation rate was 15.04% (2 days). The crosslinking of collagen sponge significantly improved its water absorption and degradation resistance.