Near infrared-triggered diketopyrrolopyrrole nanoparticles for photothermal applications against bacterial infections.

Wound infection caused by bacteria is an important factor that affects the rapid healing of wounds, and the emergence of drug-resistant strains complicates the treatment, which poses great challenges to surgeons. Therefore, we synthesized a DPP derivative (DPP-S) featuring a donor-acceptor-donor (D-A-D) structure. Through the introduction of thione groups, this derivative exhibits near-infrared (NIR) absorption and excellent photothermal performance under NIR laser irradiation. DPP-S-mediated phototherapy can effectively inhibit and destroy Staphylococcus aureus and Escherichia coli biofilms and methicillin-resistant Staphylococcus aureus biofilms. In a mouse wound infection model, DPP-S-mediated photothermal therapy can effectively fight bacterial infection, promote the formation of new blood vessels and the deposition of collagen fibers, and thus accelerate wound healing. This discovery is of great significance for the development of new photothermal agents and provides a new direction and possibility for the treatment of clinical infectious diseases.