Visible light driven photodynamic hydrogel with pH/electrophysiological dual-sensing capabilities for real-time infection monitoring and smart therapy

The smart therapy is a big challenge to the wound healing caused by bacterial infections for avoiding the antibiotic abuse. Herein, a visible light driven polyacrylamide/trehalose/Cu-Tetrakis (4-carboxyphenyl) porphyrin/bromothymol blue (CuTCPP) hydrogel with dual-sensing capabilities and on demand photodynamic therapy was synthesized by an in-situ polymerization method. The CuTCPP in the hydrogel can harvest the light for the generation of reactive oxygen species (ROS). The wound infection can be real-time monitor not only by the on-site pH variations, but also the electrophysiological signals. The sterilization efficacy of the CuTCPP hydrogel was achieved as high as 10 7  CFU mL −1 under visible light irradiation (λ ≥ 420 nm, 30 min). Remarkably, in vivo infection on mouse displayed that the photodynamic effect of CuTCPP hydrogel was much better than that of the control experimental. Importantly, the release of ROS during the wound healing can be adjusted on demand. And the hydrogel displayed good tissue adhesion, self-repairing and good biocompatibility as well. The photodynamic mechanism was investigated via the fluorescence, ESR spectra and the charge density difference analysis. Such intelligent hydrogel provided important insights for the development of precise theragnostic platforms to advanced interventions in critical wounds.