Over the past years, with the growing interest in sustainable biomaterials, marine collagen has been emerging as an interesting alternative to bovine collagen. It is more easily absorbed by the body and has higher bioavailability. In this study, collagen was extracted from Dicentrarchus labrax (sea bass) skin, a fishery by-product, thus valorizing waste streams while reducing environmental impact. To overcome the intrinsic weak mechanical of collagen, it was combined with chitosan to produce composite scaffolds for skin tissue engineering. The incorporation of collagen proved crucial for scaffold performance: (i) it promoted the formation of an open-pore architecture, favorable for cell infiltration and proliferation; (ii) it enhanced swelling behavior suitable for exudate absorption and maintenance of a moist wound environment; (iii) by tuning the chitosan/collagen ratio, it enabled us to control the degradation rate; (iv) it conferred antioxidant properties; and (iv) by adjusting collagen/chitosan concentrations, it allowed fine-tuning of mechanical properties, ensuring sufficient strength to resist stresses encountered during wound healing. In vitro assays demonstrated that the scaffolds were non-cytotoxic and effectively supported mouse adipose tissue fibroblasts’ adhesion and proliferation. Finally, all formulations exhibited marked bactericidal activity against the human pathogen Staphylococcus aureus and the methicillin-resistant Staphylococcus aureus, with a Log reduction greater than 3 (a reduction of at least 99.9% in bacterial growth) compared to the control. Collectively, these findings highlight collagen not only as a sustainable resource but also as a functional component that drives the structural, physicochemical, biological, and antimicrobial performance of chitosan/collagen scaffolds for skin tissue engineering.

The increasing incidence of jellyfish blooms and the consequent accumulation of jellyfish bycatch impose the need to explore new strategies for the valorization of this marine biomass. Jellyfish are attracting growing interest as sustainable sources of proteins, collagen, and bioactive peptides with potential applications in food, nutraceutical, and biotechnological fields. In this work, the Mediterranean jellyfish Cotylorhiza tuberculata was investigated as a source of proteinaceous fractions and enzymatic hydrolysates. Umbrella and oral arms were processed separately by phosphate-buffered saline (PBS) extraction, followed by sequential enzymatic digestion of the insoluble material with pepsin and collagenase. The resulting extracts were fractionated by membrane ultrafiltration and characterized for protein content. The fractions were then tested for antioxidant activity, angiotensin-I-converting enzyme (ACE) inhibition, effects on A2058 melanoma and HaCaT keratinocyte viability, and modulation of IL-6 response in intestinal Caco-2 cells. Collagenase-derived fractions showed the highest antioxidant activity, while ACE-inhibitory activity was mainly associated with pepsin-derived samples. Selected umbrella-derived fractions differentially affected A2058 and HaCaT cell viability. Finally, preliminary Caco-2 experiments indicated limited, fraction-dependent modulation of IL-6 levels. Overall, these results suggest that C. tuberculata may represent a useful source of protein-derived fractions with in vitro antioxidant and ACE-inhibitory activities, supporting further investigation of jellyfish bycatch as a resource for functional ingredients.