Cold and Warm Water Fish Collagen in Sodium Alginate-Based Hydrogel Structures: Application Potential in 3D Bioprinting

3D bioprinting processes show great potential in the context of repair, regeneration, and substituting damaged tissues. Incorporating biomaterials of natural origin into the structure of sodium alginate through adhesive peptides and cellular ligands effectively improves its bioactivity. Despite the advantages and common use of gelatin-based hydrogel materials, their application carries limitations. The possibility of replacing gelatin with collagen during the production of bioinks is becoming promising. Marine organisms are safe, attractive sources from the point of view of ethical restrictions, as well as abundant due to the amount of waste from collagen sources. This work focuses on analyzing the effect of different concentrations of 50-50 mixture of cold and warm water fish collagen in polymer solutions on the physicochemical and mechanical properties of the developed materials, emphasizing their significant impact on cell proliferation in bioprinted constructs. The obtained results demonstrate that increasing the concentration of fish collagen increases the system’s viscosity; at the same time, in the case of the final hydrogel materials, a higher swelling degree and improved mechanical properties can be obtained. Furthermore, the use of 1.5% (w/v) fish collagen in sodium alginate-based bioinks (2A1.5ColF) promotes proliferation and the organization of cells into extensive cellular networks, leading to the formation of tissue structures.