Ionic covalent organic framework as photo-activated nitric oxide generator for cascaded gaseous, photothermal, photodynamic and cationic bactericidal synergistic therapy

Despite great advances in bactericidal therapy, it is still hard to achieve satisfactory therapeutic effects using the single antibacterial modality nowadays, especially the emergence of drug-resistant bacteria. To address such challenge, a light-induced synergistic therapeutic platform was facilely constructed by incorporating sodium nitroprusside (SNP) into a biocompatible ionic covalent organic framework (COF), denoted as TD-COF, to combat the bacteria infection. Upon 638 nm laser irradiation, the positive charged therapeutic agents (TD-COF-SNP) with strong affinity to the negatively charged bacterial membrane could realize the photothermal-driven cascaded multimodal synergistic treatments, in which the local high temperature could not only induce the controllable generation of nitric oxide (NO), but also significantly accelerate the formation of reactive oxygen species (ROS) via the photodynamic therapy (PDT), destroying the pathogen structure, and killing pathogenic bacteria. Meanwhile, both the in vitro and in vivo assay revealed the synergistic NO/PTT/PDT/cationic triggered by laser irradiation was also highly effective for the treatment of infected wounds caused by bacteria. This work paves an avenue for the delicately design of COF-based solid state therapeutic agents toward bacteria infection treatment.