Evaluation of a chitosan/polyvinyl alcohol hydrogel loaded with graphene oxide and nano TiO2 for bone defect reconstruction in a dog model

This study evaluated the application of chitosan/polyvinyl alcohol/graphene oxide/nano titanium oxide (CS/PVA/GO/nano TiO₂) hydrogels for bone defect reconstruction in dogs. Dogs were subjected to mid-diaphyseal circular bone defects (0.8 cm²) in the radius bones. Bone defects were implanted with the hydrogel in the treated group (n = 9), while the control group were subjected to spontaneous healing (n = 9). Dogs were subjected to clinical, radiographic, and scanning electron microscopy (SEM) evaluations at 15-, 30-, and 45-days post-surgery. Dogs in the treated group recorded no lameness by the end of the third week post-surgery, while dogs in the untreated group still exhibited lameness of grade 1. There was a significant decrease (p < 0.05) in the cortical defect (mm) of the treated group (5.46 ± 0.17 and 1.45 ± 0.13) compared with the control group (7.57 ± 0.05 and 7.59 ± 0.06) at 30- and 45-days post-surgery, respectively. The depth of the bone defects (mm) decreased significantly (p < 0.05) in the treated group (2.26 ± 0.12 and 0.008 ± 0.002) compared with the untreated group (4.05 ± 0.05 and 2.16 ± 0.07) at 30- and 45-days post-surgery, respectively. Throughout the period of study, there was a significant increase (p < 0.05) in the radiographic density of the bone defects (px) in the treated group (474 ± 17.88) compared with that in the control group (619.6 ± 6.85). SEM results revealed complete closure of the bone defects in the treated group. Thus, implantation of bone defects with the CS/PVA/GO/nano TiO₂ hydrogel represents a promising bone graft substitute for accelerating bone healing.