Self-Adaptive Antibacterial Porous Implants with Sustainable Responses for Infected Bone Defect Therapy

The development of responsive antibacterial implants is highly significant for the treatment of implant-associated infection. In this study, one self-adaptive antibacterial porous implant with sustainable responses is flexibly designed and constructed for infected bone defect therapy. Porous hydroxyapatite (HA) implants derived from nature bones, one typical implant, are first functionalized via low-cytotoxic ethanediamine-functionalized poly(glycidyl methacrylate) brushes, and gentamicin sulfate (CS, a kind of aminoglycoside antibiotic in clinic) is subsequently conjugated by an acid-responsive bond to produce smart antibacterial HA implants (HA-GS). The release of GS can be triggered by the acidic environment induced by the metabolism of bacteria for self-adaptive antibacterial response. Due to the good drug loading capacity and chemical stability of HA- GS in neutral condition, the sustainable antibacterial ability is readily achieved for long-term applications. The highly effective in vivo anti-infection therapy with HA-GS is demonstrated in one infected bone defect rabbit model. The implant-associated infection is completely inhibited by HA-GS at the early stage and the defected bones exhibit superior recovery at the late stage. This design strategy of sustainable self-adaptive antibacterial implants will provide a promising concept for the prevention and therapy of implant-associated infections.