CoFe2O4 Nanoparticles Coated with Mesoporous Silica and Loaded with Naringin and Levofloxacin for Repair of Infectious Bone Defects

The treatment of infective bone defects remains a considerable challenge for orthopedic surgeons, primarily due to the complexities of infection control and the unsatisfactory healing of bone tissue. To solve this challenge, we have designed core/shell nanoparticles to loaded with antibacterial and osteogenic agents. Specifically, magnetocaloric CoFe2O4 (CF) nanoparticles loaded with naringin (NG) and coated with mesoporous silica (MS) were developed to construct NG-CF@MS nanoparticles. Subsequently, levofloxacin (LEV) was loaded into the MS coating, yielding NG-CF@MS-LEV nanoparticles capable of dual drug delivery. These nanoparticles were then incorporated into poly l-lactide (PLLA) powder to fabricate magnetically responsive scaffolds, which demonstrated enhanced osteogenesis and antibacterial activity under alternating magnetic field (AMF) conditions. Drug release studies showed a significant increase in NG and LEV release efficiency in the AMF setting, with a 337% increase in NG release and a 196% increase in LEV compared to non-AMF conditions. In vitro experiments further demonstrated that NG-CF@MS-LEV/PLLA scaffolds exhibited excellent osteogenic and antibacterial properties. Under the intervention of the AMF, the scaffolds displayed antibacterial rates of 98.67% and 99.38% against Escherichia coli and Staphylococcus aureus, respectively. Moreover, the scaffolds significantly promoted osteogenic differentiation and mineralization of mouse bone marrow mesenchymal stromal cells (mBMSCs), highlighting their potential as a promising therapeutic approach for repair of infected bone defects.