Exchange-coupled bi-magnetic nanoparticles enhance magnetothermal/chemodynamic antibacterial therapy of poly-l-lactide scaffold

Bone implant-associated bacterial infection is a common cause of transplant failure. Chemodynamic therapy (CDT) has significant antibacterial efficacy by producing reactive oxygen species (ROS). However, the ROS permeability is restricted by the natural barrier of bacterial biofilms. Herein, a hard-soft magnetic biphasic nanoparticle (CF@MF) was synthesized by in-situ growth of the soft MnFe 2 O 4 shell on the hard CoFe 2 O 4 core. Then, the CF@MF was incorporated into poly- l -lactide powders to prepare porous scaffolds by selective laser sintering. The scaffold exhibited superior magnetothermal conversion efficiency, which was attributed to the interfacial exchange coupling of CF@MF. Importantly, the scaffold effectively dispersed biofilms by magnetothermal therapy (MTT), favoring numerous ROS pre-generated by CDT to enter the interior to kill bacteria. This study provided a synergistic MTT/CDT strategy to eradicate deep bacterial infections in biomedical application.