Highly stretchable alginate/methylcellulose hydrogels for 3D bio-printing: photopolymerization approach enhancing structural integrity

In recent years, 3D hydrogels based on alginate (Alg) have undergone substantial advancements, holding transformative potential for biomedicine and regenerative medicine. Nevertheless, the viscosity of Alg needs to be further increased, in order to print complex 3D structures. Attempts to adjust printability often employ rheological modifiers like methylcellulose (MC), but these still lack mechanical integrity for broader biomedical applications. Our study sought to chemically modify Alg/MC to create a photopolymerizable hydrogel by incorporating acrylate-based monomers, which would enhance the curing ability of the base hydrogel, leading to better mechanical properties of Alg/MC, such as stretchability and stability with shape recovery. Comprehensive mechanical assessments unveiled remarkable tensile properties, achieving a notable specific strength benchmark of 44.72 kPa/(g.cm^-3) before reaching the point of fracture. This represents a substantial 250 % improvement compared to samples lacking the acrylate monomer. Biomedical assessments confirmed the hydrogel's promising potential, especially with the MG-63 cell line, underscoring its suitability for advanced applications like tissue engineering.