Injectable gelatin microspheres for osteomyelitis treatment: osteogenic and anti-inflammatory effect

Abstract

The clinical treatment of osteomyelitis usually involves surgical debridement, necrotic bone removal, and subsequent biomaterial transplantation to fill the void. The transplanted biomaterials need to be able to fight the pathogens invading the infection after trauma, orthopedic surgery or joint replacement and be able to relay regenerative events. Here, injectable vancomycin (Van)-loaded gelatin/nanohydroxyapatite (Gel/n-HA) composite microspheres (VM) with both antibacterial and bone regenerative properties were prepared for osteomyelitis treatment. The impact of Gel/n-HA-injectable composite microspheres (M) on cell recruitment, proliferation, and osteogenic differentiation was evaluated. Osteoblasts were successfully recruited by M to the bone defect area in vivo. Furthermore, the release kinetics of Van from VM in vitro and anti-inflammatory activity in vivo were assessed as the efficacy of the released antibiotics, which inhibited cell wall synthesis in Staphylococcus aureus, thereby lysing the bacterial cells. When administered topically to rabbit tibia osteomyelitis defects, the injectable VM enhanced in vivo bone healing and fracture resistance. Thus, owing to the injectability and coordinated therapeutic actions of VM, they are considered promising biomaterials with osteogenic and anti-inflammatory potential for osteomyelitis treatment.