Fabrication of Crosslinker-Free Chitosan-HPMC Hydrogel for Implant Coating: A new Approach for the Treatment of Osteomyelitis

Treatment of osteomyelitis is challenging because the systemic circulation often cannot deliver sufficient concentrations of antibiotics directly to the site of infection. The aim of this study was to fabricate a crosslinker free hydrogel coating composed of chitosan and HPMC (CH) containing gentamicin (GEM) as a promising strategy to prevent infections associated with orthopedic implants. Cytotoxicity assay showed that the hydrogel had no toxic effects against human gingival fibroblast (HGF) and mouse fibroblast L929 cells. The developed hydrogel exhibited good hemocompatibility and the capability for long-term and slow release of GEM. In vivo study revealed that the WBC and NEUT values significantly reduced in rats treated with CH-GEM (WBC: 120%, NEUT: 131%) compared to those untreated and treated with CH alone (WBC: 172%, NEUT: 264%). According to X-ray findings, the group treated with CH-GEM exhibited slight periosteal reaction and screw loosening. Histological evaluation confirmed a significant reduction in inflammatory cells in the rats treated with CH-GEM compared to the other groups. The CFU counting results displayed a significant reduction in bacterial load on the bone, decreasing from 8.5 × 10⁸ CFU in the CH group to approximately 750 CFU in the CH-GEM group. Additionally, bacterial presence in the surrounding tissues was completely eradicated, with CFU counts dropping from approximately 3000 CFU to 0 CFU. The present findings revealed that CH-GEM coating might provide a promising platform for preventing post-operative osteomyelitis.