Bifunctional cobalt ferrite/reduced graphene oxide heterojunction enhances the antibacterial and osteogenic activities of scaffold

Bacterial infection, especially in the manifestation of biofilm formation, poses a major challenge in the repair of infectious bone defects. Cobalt ferrite (CoFe₂O₄) is being investigated as a photocatalyst for generating Reactive Oxygen Species (ROS) to serve antimicrobial therapy, but it is still impeded by the ultrafast recombination of photogenerated electron-hole pairs. Herein, a CF@rGO heterojunction was constructed by in-situ growth of CoFe₂O₄ on reduced graphene oxide (rGO). Then, the CF@rGO was introduced into poly-L-lactide to fabricate bone scaffolds using selective laser sintering. Especially, rGO enhanced electron transfer and inhibited recombination of the electron-hole pairs within CoFe₂O₄, thereby accelerating ROS production. Meanwhile, rGO endowed the scaffold with excellent photothermal properties, capable of dispersing the dense bacterial biofilms and facilitating the infiltration of pre-generated ROS into the interior to eliminate deep bacteria. Additionally, the scaffold promoted cell adhesion and osteogenic differentiation, attributable to the endogenous magnetic microenvironment created by CoFe₂O₄ and strong non-covalent binding ability of rGO. Summarily, the bifunctional scaffold with antibacterial and osteogenic activities provided a promising strategy for repairing infectious bone defects.