The Extraction Of Skin Collagen And Collagen Biofilm Material

Collagen is regarded as one of the most useful biomaterials. The excellent antigenicity, biocompatibility, degradability and hemostasia ability are the advantages of collagen as biomaterials, due to its special biological structure. It is easily absorbable, nontoxic in the body, and hydrophilic, making collagen the primary resource in medical applications.Collagen can be extracted by several methods, in which neutral salt and alkali treatment have the drawbacks, while acidic and enzymatic extraction hold their advantages. Acidic and enzymatic extraction were employed in part one. Enzyme dosage, duration and pH variation, the key factors effecting preparation process, were studied. The results indicated that, to acidic method, within pH1.7-2.0, collagen gave 82.7%-82.8% total solubility rate at about 30hr. To enzymatic processing, pH1.9-2.1, 30hr, pepsin at a 40:1 weight ratio of dry weight tissue to enzyme could fulfill manufacturing requirement. Collagen sample were purified to take following evaluation test: amino acid determination, FT-IR analysis, differential scanning calorimetry. Original triple helix structure were showed well preserved and characteristics of the sample were showed matching the native collagen.Collagen film can get enough tensile strength and biological stability by cross-linking, which is very important for film biomaterials. Tannic acid was chosen as cross-linking agent in part two to modify dried collagen film, due to its unique and diverse physiological, pharmacological activity. The degree of cross-linking was indicated proportional to the uptake of tannic acid, which varied between 15 and 34%, Enzymatic degradation resistance of collagen film was studied. Tannic acid-treated collagen film showed a slow degradation rate relative to non-cross-linked, glutaraldehyde cross-linked collagen materials when subjected to pancreatic proteolytic enzyme. The optimal tannic acid solution concentration was 12.5%, at which collagen film reached the Tm value 81℃.Tannic acid cross-linked collagen film was suitable for biomaterial dependent on its sufficient degree of cross-linking, low enzymatic degradation rate.