Regulating the bacterial oxygen microenvironment via a perfluorocarbon-conjugated bacteriochlorin for enhanced photodynamic antibacterial efficacy

Photodynamic therapy (PDT) has attracted considerable attention, since it could effectively kill bacteria and prevent the development of multi-drug resistance. However, PDT currently suffers from oxygen limitation and hypoxia is a prominent feature of pathological states encountered in inflammation, wounds, and bacterial infections. Herein, an oxygen-tunable nanoplatform based on perfluorocarbon-conjugated tetrafluorophenyl bacteriochlorin (FBC-F) was designed for effective antimicrobial therapy . The introduction of fluorine atoms can not only increase the reactive oxygen species (ROS) production capacity of FBC-F by facilitating the intersystem crossing (ISC) process of FBC photosensitizers , but also make FBC-F deliver more oxygen into the treatment sites benefiting from the outstanding oxygen-dissolving capability of perfluorocarbon . As a consequence, the FBC-F nanoplatform was able to efficiently generate singlet oxygens for type II PDT, as well as superoxide anions and hydroxyl radicals for type I PDT, and significantly improve antibacterial efficacy in vitro. In vivo experiments further proved that the FBC-F with a powerful antibacterial capability could well promote wound healing and destroy biofilm . Thus, this FBC-F nanoplatform may open a new path in photodynamic antibacterial therapy . Statement of significance Photodynamic therapy is a promising antibacterial treatment, but its efficacy is severely compromised by hypoxia . To overcome such a limitation, we constructed an oxygen-regulated nanoplatform ( FBC-F ) by attaching perfluorocarbons (PFC) to the NIR photosensitizer ( FBC ). As an analogue of bacteriochlorin , FBC could generate 1 O 2 through energy transfer , as well as O 2 −· and ·OH through electron transfer for synergistic type I and type II photodynamic antibacterial therapy. Benefiting from the oxygen-dissolving capability of PFC, FBC-F could efficiently deliver more oxygen into the treatment site and alleviate the hypoxic environment. As a consequence, FBC-F could effectively generate large amounts of reactive oxygen species to achieve improved antibacterial efficacy and provide a promising approach for eliminating biofilms.