Phthalocyanine self-assembled nanoparticles for type I photodynamic antibacterial therapy

Most photodynamic therapies (PDT) rely on reactive oxygen species (ROS) produced by type II mechanisms. However, since the production of type I ROS is not limited by oxygen content, making it more favorable for antimicrobial phototherapy in complex microenvironments. Herein, we report a substituent cationization design strategy that not only improves the hydrophilicity of the prepared phthalocyanine molecule, but also promotes the electron transfer process in the photosensitizer, resulting in the strong type I photodynamic effect of the phthalocyanine self-assembled photosensitizer to efficiently generate O2•- under both normal and hypoxic conditions. This in combination with its excellent bacteria recognition capability derived from the cationic part on its surface and intrinsic photothermal therapy effect of the phthalocyanine macrocycle endows the phthalocyanine self-assembled photosensitizer with excellent phototherapeutic antimicrobial properties in preclinical models, effectively promoting the wound healing process. This work provides a promising strategy for designing efficient multi-mode photosensitizers.