Cationic Cu(I)-covalent organic framework as self-enhanced synergetic Photothermal/Phtodynamic/Cationic/Enzymatic antibacterial agent

Combination therapy, functioned by the integration of two or more therapies, simultaneously, into one platform, have gained wide popularity to combat antibiotic-resistant bacteria in both the clinical trials and fundamental researches. Here, a multifunctional cationic Cu(I)-covalent organic framework (COF), denoted as HLVCu, which could realize the joint action of photothermal/photodynamic/cationic/enzymatic therapies was facilely fabricated as an antimicrobial therapy platform. This material enables an amplified synergistic therapeutic effects to combat bacteria. The intrinsic photothermal activity could enhance the enzymatic activity, which is closely related to temperature to effectively catalyze the generation of toxic hydroxyl radical (•OH) from low concentration H2O2 to synergize with photothermal therapy. The positive charged skeleton structure allows the material to interact better with the bacterial membrane, which could decrease the diffusion distance of reactive oxygen species (ROS), realizing the quickly and effectively killing of bacteria. Under the laser irradiation, the present HLV-Cu could act as a broad-spectrum antibacterial agent, delivering an extremely high sterilization efficiency of 100% towards the gram positive (S. aureus) and gram negative (E. coli) model microorganisms, simultaneously, at a low dose of agents. Altogether, this work offers a new and safe antibiotic-free treatment option for high-efficiency combination antimicrobial therapy.