Polypyrrole hydrogel with near-infrared light-driven nitric oxide release and photothermal activities for rapid synergistic sterilization and infected wound therapy

Developing low-cost and easy-accessible phototherapy agents with a high sterilization efficiency is urgently needed tackling the increasingly dangerous of bacterial infections. Herein, a broad-spectrum antimicrobial agent (i.e., PP-Mo-NO) with near-infrared laser (NIR) driven nitric oxide (NO) release capacity derived from the assemble of a heat-sensitive NO donor (N, N′-di-sec-butyl-N, N′-dinitroso-1, 4-phenylenediamine, BNN6) with freeze-dried three-dimensional polypyrrole hydrogel crosslinked by the sulfonated dimolybdenum-salen (PP-Mo), was synthesized for the rapid and effective eradicating of Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). Upon 808 nm laser irradiation, PP-Mo-NO showed not only superb photothermal efficacy (79.88 %), but also precisely controllable NO release capacity, generating oxidative/nitrosative stress. Within 10 mins of irradiation (1.0 W cm−2), PP-Mo-NO with co-amplified photothermal (PTT)/NO synergetic antibacterial activity presented sterilization rates beyond 99.1% against both the E. coli and S. aureus at a relatively low concentration (100 µg mL−1). Meanwhile, in vivo experiments demonstrated the great application potential of PP-Mo-NO which could effectively kill bacteria at the site of infection, and repair the open infectious wounds, thereby accelerating the tissue reconstruction.