An Injectable Nanocomposite IPN Hydrogel Based on Gelatin Methacrylate/Alginate/COF for Tissue Engineering Applications

The primary request nowadays is for innovative and superior scaffold designs that mimic the characteristics of native tissue in cartilage tissue engineering. GelMA/Alginate (G/A) interpenetrating polymer network (IPN) has become a popular hydrogel material for tissue engineering because of its superior mechanical and biological properties. Here, to balance the properties, a hydrogel composed of G/A and covalent organic frameworks (COF) nanoparticles is specially designed. In this study, a hydrogel of GelMA/Alginate/COF (G/A/C) with improved properties such as pore size, swelling, mechanical strength, shear-thinning behavior, and biocompatibility is produced. Furthermore, the G/A/C hydrogel facilitate the printing of complex three dimensional (3D) scaffolds. The test result demonstrates that the addition of COF up to 1% (w/w) enhances the porosity and decreases pore size (0.2 times), improves the compression strength (six times), and decreases the degradation ratio (0.05 times) and the swelling (0.3 times) compared to the G/A hydrogel sample. Besides, the cell viability test confirms the cell growth during the incubation and great biological behavior (more than 98%). The suitable performance of the G/A hydrogel containing 1% COF and its shape fidelity during the injection by 3D printer is confirmed. Nanocomposite IPN hydrogel based on G/A/C could be useful in tissue engineering applications.