Bacterial microenvironment-responsive dual-channel smart imaging-guided on-demand self-regulated photodynamic/chemodynamic synergistic sterilization and wound healing.

Abstract

Bacterial infections pose a serious threat to public health. The integration of photodynamic therapy (PDT) and chemodynamic therapy (CDT) has emerged as a promising means to combat bacterial infection. However, most photosensitizers are often in the "always on" activated state and lack bacterial targeting, leading to non-specific damage to normal tissues. Besides, most of the conventional CDT systems are directly complexed with metal ions. The toxicity of excess free metal ions cannot be ignored. Therefore, it is a huge challenge to construct a bacteria-specific activated PDT/CDT synergistic therapy platform to achieve precise sterilization. Herein, we report a bacterial microenvironment-responsive phosphorescence/fluorescence dual-channel smart imaging-guided on-demand self-regulating CDT/PDT theranostic platform for precise sterilization and wound healing. Acid-degradable persistent luminescence nanoparticles were prepared as bacterial microenvironment-responsive phosphorescence imaging units and CDT agents. Piperazine-modified PEG was then introduced as an intelligent targeting and hydrophilic group, which was further bonded with a pH-reversibly-activated fluorescence/PDT-in-one probe to construct the intelligent theranostic platform. The developed platform combines the features of good biocompatibility, prolonged blood circulation, charge-reversed intelligent targetability, dual-channel smart imaging and on-demand self-regulating CDT/PDT effect, holding great potential for precise imaging-guided bacteria-specific synergistic sterilization without side effects.