Fabrication of crosslinker-free chitosan-HPMC hydrogel for implant coating: a new approach for the treatment of osteomyelitis

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. The developed hydrogel exhibited good hemocompatibility, no cytotoxicity and the capability for long-term and slow release of GEM. <i>In vivo</i> 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.