Photothermal effect of graphene oxide accelerate singlet oxygen release from artesunate to endow the scaffold with antibacterial properties

Abstract

Artesunate, as a semi-synthetic artemisinin derivative, exhibits a broad-spectrum bactericidal effect via the release of singlet oxygen. However, its release is slow due to the difficulty breaking the endoperoxide bridge bond. Ammoniated graphene oxide could be electrostatic adsorbed with artesunate and efficiently transfer thermal energy to artesunate by interfacial heat transfer, thereby facilitating the breaking of the endoperoxide bridge bond. In detail, artesunate was anchored on graphene oxide by a one-pot hydrothermal synthesis method and introduced to the PLLA scaffold fabricated by selective laser sintering. Under near-infrared light irradiation, graphene oxide could convert light to heat through photothermal conversion. Then the heat energy was transferred to artesunate by interfacial heat transfer, accelerating the release of singlet oxygen. Meanwhile, graphene oxide could achieve the purpose of thermal ablation for bacterial infection by increasing the local temperature. Based on the combination of singlet oxygen and thermal ablation therapy, the scaffold possesses a high bactericidal ability triggered by near-infrared light. Under the near-infrared light irradiation, the singlet oxygen production from artesunate increased by 39 %, and the antibacterial ratio against S. aureus and E. coli reached 91.6 % and 93.3 %, respectively. Additionally, the scaffold was favorable cytocompatibility with mBMSCs. All the results highlight the great potential of artesunate-mediated graphene oxide scaffold in eliminating bacterial infections.