To improve wound healing, advanced biofabrication techniques are proposed here to develop customized wound patches to release bioactive agents targeting cell function in a controlled manner. Three-dimensional (3D) bioprinted “smart” patches, based on methacrylated gellan gum (GGMA), loaded with tannic acid (TA) or L-ascorbic acid (AA) have been manufactured. To improve stability and degradation time, gellan gum (GG) was chemically modified by grafting methacrylic moieties on the polysaccharide backbone. GGMA patches were characterized through physicochemical, morphological and mechanical evaluation. Kinetics release and antioxidant potential of TA and AA as well as antimicrobial activity against common pathogens Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli in accordance with ISO 22196:2011 are reported. The cytocompatibility of the patches was demonstrated by direct and indirect tests on human dermal fibroblasts (HDF) as per ISO 10993. The positive effect of GGMA patches on cell migration was assessed through a wound healing assay. The results highlighted that the patches are cytocompatible, speed up wound healing and can swell upon contact with the hydration medium and release TA and AA in a controlled way. Overall, the TA- and AA-loaded GGMA patches demonstrated suitable mechanical features; no cytotoxicity; and antioxidant, antimicrobial and wound healing properties, showing satisfactory potential for wound dressing applications.

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.