Dual-type photodynamic therapy enabled by fluorinated BODIPY-liposome hybrids for enhanced antibacterial efficacy

Abstract

The widespread misuse of antibiotics has accelerated bacterial evolution, precipitating a global antimicrobial resistance (AMR) crisis. Photodynamic therapy (PDT) has recently emerged as a promising alternative due to its non-invasiveness, cost-effectiveness and broad-spectrum antimicrobial activity. Boron-dipyrromethene (BODIPY) derivatives constitute a promising class of organic photosensitizers with experimentally verified photodynamic activity. However, conventional BODIPY-based photosensitizers face significant limitations: their inherent hydrophobicity reduces reactive oxygen species (ROS) generation efficiency, diminishes antimicrobial coverage, and may paradoxically promote resistance development. Furthermore, their exclusive production of Type I PDT, without complementary Type II mechanisms, substantially restricts their therapeutic potential. ‌Herein, a series of photosensitizers (PSs) with antibacterial properties was developed by leveraging electron push-pull systems coupled with heavy-atom effects. In addition to enhance the aqueous solubility of photosensitizers, three types were encapsulated into liposomes via the thin film hydration method. Benefiting from sufficient molecular rotors and high electronegativity of fluorine, the developed BDP-F Lips exhibit superior ROS generation capacity under laser irradiation, concurrently producing both Type I and Type II PDT, thereby demonstrating excellent antibacterial efficacy.