Copper(ii)-infused porphyrin MOF: maximum scavenging GSH for enhanced photodynamic disruption of bacterial biofilm

Abstract

Bacterial biofilm infection is a serious obstacle to clinical therapeutics. Photodynamic therapy (PDT) plays a dynamic role in combating biofilm infection by utilizing reactive oxygen species (ROS)-induced bacterial oxidation injury, showing advantages of mild side effects, spatiotemporal controllability and little drug resistance. However, superfluous glutathione (GSH) present in biofilm and bacteria corporately reduces ROS levels and seriously affects PDT efficiency. Herein, we have constructed a Cu²⁺-infused porphyrin metal–organic framework (MOF@Cu²⁺) for the enhanced photodynamic combating of biofilm infection by the maximum depletion of GSH. Our results show that the released Cu²⁺ from porphyrin MOF@Cu²⁺ could not only oxidize GSH in biofilm but also consume GSH leaked from ROS-destroyed bacteria, thus greatly weakening the antioxidant system in biofilm and bacteria and dramatically improving the ROS levels. As expected, our dual-enhanced PDT nanoplatform exhibits a strong biofilm eradication ability both in vitro and in an in vivo biofilm-infected mouse model. In addition, Cu²⁺ can promote biofilm-infected wound closing by provoking cell immigration, collagen sediment and angiogenesis. Besides, no apparent toxicity was detected after treatment with MOF@Cu²⁺. Overall, our design offers a new paradigm for photodynamic combating biofilm infection.