Smart Trap-Capture-Kill Antibacterial System for Infected Microenvironment Improvement and Vascularized Bone Regeneration via Magnetic Thermotherapy

摘要

Infected bone defect has gradually become a disastrous complication inorthopedic surgery because of the bacterial biofilm formation both on thesurface of the implants and surrounding tissues, which will cause antibioticresistance and weak postoperative osseointegration. Herein, drug-loadedhollow mesoporous ferrite nanoparticles coated by gelatin (GM/HMFNs)with pomegranate structure are prepared and compounded into calcium magnesiumphosphate cement (MCPC) as a Trap-Capture-Kill system to kill bacteriaand inhibit biofilm formation efficiently. Under the action of alternatingmagnetic field (AMF), MCPC/GM/HMFNs/Drug composites exhibit acutemagnetic hyperthermal capacity and recruit the free bacteria. Then, the permeabilityof bacterial cell membrane is increased via reactive oxygen species(ROS) damage of nano-MgO and HMFNs, providing channels through whichvancomycin (Van) and ciprofloxacin (CPFX) encapsulated in GM/HMFNs canpenetrate. Subsequently, the bacteria are efficiently killed under the synergeticcooperation of magnetothermal effect, ROS damage, and adsorption damageof nano-MgO, and the bioactive ions and drugs. The antibacterial systemalso presents outstanding pro-osteogenesis and pro-angiogenic capacity invitro. And it promotes the vascularized bone regeneration of infective femoraldefect in SD rats in vivo, providing promising potential for the treatment ofinfected bone defects through magnetothermal therapy.