3D printing and chitosan complexation of ulvan/poly(vinyl alcohol) hydrogels for wound healing

The application of 3D printing to ulvan (Ulv), a seaweed-derived polysaccharide, offers novel strategies for fabricating customized hydrogels that align with the concept of sustainable development. However, to date, this possibility has been demonstrated only for photo-crosslinkable Ulv derivatives and not for native Ulv itself. In this context, this research activity aimed to develop a novel 3D printing approach for processing an aqueous formulation based on native Ulv into hydrogels for wound dressing applications. To this purpose, a protocol for direct blending of Ulv with poly(vinyl alcohol) (PVA) (50:50 wt) in aqueous solution and depositing the resulting mixture into an ethanol bath was optimized for the 3D printing of hydrogels with different inter-fiber axial distances (1, 2, or 4 mm). The 3D printed hydrogels were stable in an aqueous medium for 2 weeks upon polyelectrolyte complexation with chitosan (Cs), as demonstrated by water uptake, spectroscopic, and thermal analyses. Swollen 3D printed hydrogels had a tensile modulus in the range of 17–25 kPa, meeting the requirements for wound healing applications, as well as an elongation at break exceeding 180%. In vitro investigations employing a murine fibroblast cell line showed the cytocompatibility of the 3D printed hydrogels and their ability to support the wound healing process. The binding efficacy of the 3D printed hydrogels with key proteins playing critical roles in the progression and healing of wounds was explored in silico by analyzing Matrix Metalloproteinase-9 (MMP9) and Transforming Growth Factor β-1 (TGF - β1) . The obtained results represent an encouraging starting point for the fabrication of 3D printed hydrogels for wound care applications using a native seaweed-derived polysaccharide without chemical modification.