Biotechnological applications of Echinoderm mutable collagenous tissues

Echinoderms possess unique connective tissues (Mutable Collagenous Tissues, MCT) which display striking passive mechanical properties. These tissues are widespread in all the five extant echinoderm classes and are fundamental for many aspects of their biology. Besides their evident physiological relevance, MCT can also be a promising source of inspiration and material, namely collagen, for biotechnological applications, as an alternative to the widely used mammalian sources. Collagen-made materials are the most promising in regenerative medicine: in the field of Guided Tissue Regeneration collagen barrier-membranes of mammalian origin (BM) are typically used to facilitate proper tissue regrowth in anatomically separated compartments. Recently, we have proposed the sea urchin peristomial membrane as a target MCT for the extraction of native collagen fibrils and the development of innovative membranes (Di Benedetto et al., 2014). In the present work we used and compared MCT from different echinoderm models, representative of the diverse classes (sea urchin, starfish and sea cucumber) to prepare echinoderm-derived membranes (EDM). The EDM were characterized and compared in terms of structure, biomechanics and human cell behaviour (skin-derived fibroblasts). BM or substrates made of soluble or re-fibrillated bovine collagen were used as further comparison. All the EDM were similar in terms of structure (highly dense fibrillar network) and mechanical performances, but all of them were much thinner (~20-30 folds) and mechanically more resistant (~20 folds) than the commercially used BM. Fibroblasts seeded on the EDM were generally less numerous than those on mammalian collagen substrates (except in the case of the sea urchin-derived collagen membranes, which were similar) and displayed a more elongated shape, less numerous filopodial processes and a different cytoskeletal organization, all these features suggesting a weaker cell attachment. Overall, our data indicate that all the echinoderm models can be considered potential alternative source of collagen to produce membranes suitable for Guided Tissue Regeneration, where high mechanical resistance, low cell attachment and dense fibrillar network for a barrier-effect are required. Nevertheless, sea urchins might display some advantage, also in terms of eco-sustainability (by recycling tissues from food wastes). Further in vivo tests are necessary to confirm the validity of this innovative marine biomaterial. References Di Benedetto C, Barbaglio A, Martinello T, Alongi V, Fassini D, Cullorà E, Patruno M, Bonasoro F, Barbosa MA, Candia Carnevali MD, Sugni M. 2014. Production, Characterization and Biocompatibility of Marine Collagen Matrices from an Alternative and Sustainable Source: The Sea Urchin Paracentrotus lividus. Marine Drugs. 12: 4912-4933.