Background: Clinicians frequently face difficulties when trying to fix bone abnormalities. Gelatin-Alginate (GA) is frequently employed as a carrier because it is non-toxic, biodegradable, and has a three-dimensional network structure. Meanwhile, cerium oxide nanoparticles (nCeO₂) demonstrated high antioxidant enzyme simulation activity. Therefore, in order to develop a porous hydrogel scaffold for the application of bone tissue engineering, an appropriate-type GA-nCeO₂ hydrogel scaffold was developed and evaluated.
Methods:  GA-nCeO₂ hydrogel scaffold was prepared by the lyophilized method and characterized. The surface morphology and cell adhesion of the scaffold were observed by the scanning electron microscope. CCK8 and live-dead staining methods were used to evaluate its biological safety and cell proliferation. Then the osteogenic differentiation in early and late stages was discussed. The expression of osteogenic genes was also detected by RT-PCR. Finally, a bone defect model was made in SD rats, and bone formation in vivo was detected.
Results:  The results showed that GA-nCeO₂ hydrogel scaffold exhibited a typical three-dimensional porous structure with a mean pore ratio of 70.61 ± 1.94%. The GA-nCeO₂ hydrogel was successfully endowed with simulated enzyme activity including superoxide dismutase (SOD) and catalase (CAT) after the addition of nCeO₂. Osteoblasts demonstrated superior cell proliferation and adhesion on composite scaffolds, and both mineralization test and gene expression demonstrated the strong osteogenic potential of GA-nCeO₂ hydrogel. The outcomes of hematoxylin and eosin (H&E) staining and Masson trichrome staining in the femoral defect model of SD rats further supported the scaffold’s favorable biocompatibility and bone-promoting capacity.
Conclusion: Due to its favorable safety, degradability, and bone formation property, GA-nCeO₂ hydrogel was anticipated to be used as a potential bone defect healing material.
Keywords: bone regeneration, cerium oxide nanoparticles, hydrogel, bone defect