Synthesis and investigation of physicochemical properties of alginate dialdehyde/gelatin/ZnO nanocomposites as injectable hydrogels

Abstract

There has been a great interest in injectable hydrogels for cartilage tissue regeneration since it can simply fill damaged defects within minimum invasive surgical therapies. Injectable nanocomposite hydrogels provide a three-dimensional (3D) scaffold that fits perfectly with the defects and combines the structure of an extracellular matrix to mimic cartilage cells. In this research, we present novel thermoresponsive injectable gelatin (GEL)/oxidized alginate (OA) hydrogels reinforced by zinc oxide nanoparticles (ZnO NPs) and N-hydroxysuccinimide (NHS)/1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) as chemical cross-linkers of polymer chains in the 3D scaffold system. The effect of ZnO NPs concentrations was investigated on the mechanical properties of scaffolds, and the outcomes revealed that boosting ZnO NPs content improved the storage modulus of the hydrogel by more than five folds. Comprehension of the injectable hydrogel viscoelasticity is essential in the formulation of suitable GEL/OA/ZnO nanocomposite scaffolds for cartilage tissue engineering. The morphology of the scaffolds possesses porous structures. The scaffold containing 0.05% ZnO NPs has a denser structure compared with uncross-linked hydrogel, and the pore size reduces by increasing the amount ZnO NPs. The in vitro swelling ratio has decreased at higher quantity of ZnO, due to the smaller pore sizes in the scaffolds, which minimizes the water absorption. The in vitro biodegradation reveals that the scaffold containing a higher amount of ZnO NPs (0.05%) is more durable than the one without ZnO NPs. The nanocomposite scaffold exposed biocompatibility >90% for MTT assay and excellent cell adhesion to MG-63 cells.