Composite PLLA/Ag@SiO2 microspheres for bone regeneration in infected bone defects

Repairing bone defects is particularly challenging when an infection is presented. In this study, poly(L-lactic) (PLLA) nanofibrous microspheres (large microspheres) were used as cell carriers to simulate the nanofibrous structure of the extracellular matrix. A planet-satellite composite microsphere with large microspheres and small microspheres was constructed by bonding hollow Ag@SiO2 nanospheres (small microspheres) to nanofibrous PLLA microspheres. According to the results, PLLA nanofibrous microspheres activated by EDC and NHS can firmly combine with Ag@SiO2 nanospheres. The composite microspheres demonstrated excellent drug release functions, antibacterial properties, and biocompatibility and promoted cell adhesion and differentiation in vitro. The bone repair function of composite microspheres loaded with BMP2 growth factor was evaluated in rat that were infected with bacteria and exhibited skull defects. A four-week study showed that these microspheres significantly promoted bone regeneration in infected bone. These multifunctional microspheres could revolutionize bone repair and provide a much-needed solution for those suffering from infected bone defects.