Marine Spongia collagens: Protein characterization and evaluation of hydrogel films

Fibrous proteins such as collagens are important raw materials for the production of new bio-based or biomimetic materials. A rich source of collagen is found in the extracellular skeletal matrix of marine or sea sponges, an anatomically simple animal species. This abundant source of collagens was explored for its potential to create a hydrogel suitable as a biomaterial for drug delivery and tissue engineering. Collagen proteins were extracted from the skeletons of hard and soft species of sponges from the Spongia genus. The protein profile, amino acid composition, and partial sequences of the extracted proteins were determined, and the protein extracts were fabricated with chitosan and organic cross-linkers to create hydrogel films. The amino acid compositions and sequences of Spongia collagens are similar to collagens obtained from other species. Spongia collagens are hydrophilic and mechanically fragile. Blending these with chitosan and the organic crosslinkers, genipin and glyceraldehyde, formed blended films with improved mechanical performance and structural integrity and improved stress–strain and water swelling characteristics. These material properties show the potential of the films to be used as hydrogel biomaterials in medical applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47996.