Mechanical and Dimensional\nStability of Gelatin-Based\nHydrogels Through 3D Printing-Facilitated Confined Space Assembly

Hydrogels have emerged as promising biomaterials for\ntissue regeneration;\nyet, their inherent swelling can cause deformation and reduced mechanical\nproperties, posing challenges for practical applications in biomedical\nengineering. Traditional methods to reduce hydrogel swelling often\ninvolve complex synthesis procedures with limited flexibility. Inspired\nby nature’s efficient designs, we present here the approach\nto improve hydrogel performance using 3D printing-assisted microstructure\nengineering. By utilizing polymerization-induced phase separation\nof hydrogel from copolymerization of gelatin methacrylate and hydroxyethyl\nmethacrylate (poly(GelMA-co-HEMA)) in the confined space during vat\nphotopolymerization (VPP) 3D printing, we replicate the cuttlebone-like\nmicrostructure of hydrogels with enhanced mechanical properties and\nswelling resistance. We demonstrate here a 4-fold increase in elastic\nmodulus compared to bulk polymerization of poly(GelMA-co-HEMA), together\nwith improved mechanical and dimensional stability. This method offers\npromising opportunities for practical biomedical and tissue engineering\napplications, overcoming previous limitations in the design and performance.