Introduction: Collagen is the most abundant protein of animal connective tissues, found in skins, bones or cartilages, which turn it into one of the key polymers to be considered for biomedical applications, namely tissue engineering and drug delivery. Current industrial procedures to extract collagen involves bovine and porcine as main sources. However, due to religious factors and the risk of transmitting diseases to humans, the search for new sources has been growing.Marine origin is one of the alternatives that has been explored, particularly, through by-products of fish processing, such as skins, scales or spines, with both economic and environmental benefits [1]. In this work, collagen was extracted from shark Scyliorhinus canicula skin. The collagen was processed and further evaluated as alternative for dermal membranes, regarding sustained release of drugs. Materials and methods: Extraction of collagen: Skins of shark (Scyliorhinus canicula) were treated with 0.1 M NaHO to remove non-collagenous proteins, cleaned with distilled water and then collagen was extracted with 0.5 M acetic acid, overnight. After centrifugation, the supernatant was purified by dialysis and the resultant collagen solution was freeze-dried. The produced collagen was characterized by FTIR, SDS-PAGE, aminoacid composition and l-DSC. Preparation of membranes: Collagen was dissolved in 0.5 M acetic acid to obtain 1% (w/v) solution. Then, a 5% (v/v) hexamethylene diisocyanate (HMDI) was added at a ratio of 1% and 5% with respect to collagen, and allowed to react for 24 h. The mixture was cast in Petri dish, and let to dry at room temperature. Non-crosslinked membranes were prepared as reference. In order to prepare membranes for drug delivery assessment, dexamethasone was added to the collagen solutions and membranes were prepared as described. Collagen membranes were characterized by determining water contact angle, mechanical properties and stability in PBS. Furthermore, the release profile of dexamethasone was also determined. Results: SDS-Page analysis indicates that the extracted collagen from shark skin is mainly of type I. l-DSC analysis indicates a denaturation temperature of about 33°C, lower than mammalian collagen. The aminoacid analysis confirmed the presence of hydroxyproline and the high quantity of glycine, characteristic of collagen. Collagen membranes showed more stability in PBS as long as the degree of crosslinking is higher, which also influences their mechanical properties. Moreover, the crosslinking degree also affects the hydrophobicity of the membranes. The release profile of dexamethasone was evaluated, with the drug being released in a progressive and sustained manner. Discussion and conclusions: Collagen has been successfully extracted from shark skins and used on the preparation of membranes by solvent casting. The properties of the collagen membranes can be tunned, according to crosslinking degree, revealing a promising potential for application in biomedical field, namely as dermal membranes for controlled drug release. Acknowledgments: Funding is acknowledged from projects IBEROMARE, MARMED and POLARIS. FCT Post-doc fellowship (JMS) is also acknowledged
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