Synthesis and Characterization of a Marine Collagen-Chitosan/HA-SiO₂-Based Bioink

In this work, we report the synthesis and evaluation of a bioink based on marine collagen, chitosan, and silica-doped hydroxyapatite (HA-SiO₂) for extrusion-based 3D bioprinting. FTIR spectroscopy confirmed amide (I-III) and phosphate/siloxane signals, TGA showed initial dehydration and degradation stages compatible with the process's thermal handling, and SEM revealed an interconnected porous microstructure. Rheologically, the ink exhibited elastic dominance (G' > G″) within the linear range and pseudoplastic, shear-thinning behavior-consistent with pneumatic extrusion. Process evaluation on a BIO X printer (14 G nozzle, low print speeds, moderate pressure, cartridge at 37 °C to 45 °C, and a cooled build platform) enabled deposition of strands with local shape retention. However, filament continuity was limited and line width varied, indicating only preliminary printability and a narrow operating window. Overall, physicochemical, microstructural, and rheological evidence supports the formulation's viability as a starting point for scaffold fabrication.