Circular economy: characterization of collagen peptides from sea urchin waste

The concept of Circular Economy is based on the recycling and exploitation of wastes that can be used as a source of “secondary resources”. In this framework, we have recently started two research projects (CIRCULAr and BRITEs) addressed to the recycling of food wastes of the sea urchin industry and their valorization in different products, including collagen-based biomaterials for tissue regeneration applications. In previous works we developed and characterized these innovative sea urchin-derived medical device prototypes in terms of structure, mechanical performances, efficacy and in vitro cytocompatibility. In the present work we further characterized them in terms of collagen aminoacidic composition, in vitro degradation rates in physiological (PBS) and enzymatic (collagenase) conditions, preliminary antioxidant activity as well in vitro cytotoxicity (human fibroblasts) of the biomaterial degradation products i.e. collagen peptides. These peptides could in turn become “bioactive molecules” useful in the regenerating tissue microenvironment. Amino acid profiling confirmed that sea urchin collagen is mainly composed of glycine, hydroxyproline and proline and its overall aa composition is similar to that of human collagen, with a few small exceptions for alanine, arginine, methionine and glutamic acid. Degradation test showed that in collagenase scaffolds are degraded by more than 50% after 48 hours and Integra, a commercially available bovine collagen membrane used as a control, by less than 10%. Preliminary evaluation of antioxidant activity suggest that the collagen peptides might have a potential role as radical scavenger and therefore anti-inflammatory biomolecules. Finally, the cytotoxicity showed that in a short time (24h) the higher concentrations of peptides seem to have a “beneficial” effect, favoring the vitality (and indirectly the proliferation) of human dermal fibroblasts. Overall, in the present work we provided further evidence of the suitability and potential usefulness of our innovative and ecofriendly biomaterial for biomedical applications. As expected, this has good biodegradability rates which can be useful in vivo allowing the progressive substitution and regeneration of the new tissue. Further in vivo study will provide information on the actual efficacy of this novel biomaterial.