Pillar[5]arene-Based Acid-Triggered Supramolecular Porphyrin Photosensitizer for Combating Bacterial Infections and Biofilm Dispersion

The treatment of pathogenic bacterial infection has long been the most serious threat to human life and attracted widespread attention. Herein, a supramolecular photosensitizer platform based on carboxylatopillar[5]arene (CP5) and tetrafluorophenyl porphyrin functionalized with a quaternary ammonium group (TFPP-QA) for combating bacteria and dispersing biofilm via photodynamic treatment is constructed. By introducing the host macrocycle CP5 and host-guest interaction, the supramolecular photosensitizer has great biocompatibility and acid responsiveness. On the one hand, the acid-triggered dissociation of TFPP-QA/CP5 could induce the porphyrin photosensitizer to target bacterial cells and disrupt the charge balance of bacterial membranes, enhance the permeability of the bacterial membrane. On the other hand, the TFPP-QA/CP5 antibacterial platform possesses superb reactive oxygen species (ROS) generation capability under light irradiation, leading to enhanced photodynamic antibacterial efficacy. The in vitro and in vivo studies show that the supramolecular photosensitizers exhibit high antibacterial efficiency and biofilm dissipation effect under 660 nm light irradiation. Therefore, it is anticipated that the rational design and integration of photosensitizers and quaternary ammonium compounds through the supramolecular strategy would provide a promising prospect for clinical photodynamic antimicrobial therapy.