In Situ Growth of a Metal–Organic Framework on Graphene Oxide for the Chemo-Photothermal Therapy of Bacterial Infection in Bone Repair

Bacterial infection with high morbidity (>30%) seriously affects the defect's healing after bone transplantation. To this end, chemotherapy and photothermal therapy have been utilized for antibacterial treatment owing to their high selectivity and minimal toxicity. However, they also face several dilemmas. For example, bacterial biofilms prevented the penetration of antibacterial agents and local temperatures (over 70 °C) caused by the photothermal therapy damaged normal tissue. Herein, a co-dispersion nanosystem with chemo-photothermal function was constructed via the in situ growth of zeolitic imidazolate framework-8 (ZIF-8) on graphene oxide (GO) nanosheets. In this nanosystem, GO generates a local temperature (∼50 °C) to increase the permeability of a bacterial biofilm under near-infrared laser irradiation. Then, Zn ions released by ZIF-8 seized this chance to react with the bacterial membrane and inactivate it, thus realizing efficient sterilization in a low-temperature environment. This antibacterial system was incorporated into a poly-l-lactic acid scaffold for bone repair. Results showed that the scaffold showed a high antibacterial rate of 85% against both Escherichia coli and Staphylococcus aureus. In vitro cell tests showed that the scaffold promoted cell proliferation.