Antibacterial Photodynamic Gold Nanoparticles for Skin Infection

Damage or injury to the skin creates wounds that are vulnerable to bacterial infection, which in turn retards the process of skin regeneration and wound healing. In patients with severe burns and those with chronic diseases, such as diabetes, skin infection by multidrug-resistant bacteria can be lethal. Therefore, a broad-spectrum therapy to effectively eradicate bacterial infection through a mechanism different from that of antibiotics is much sought after. We successfully synthesized antibacterial photodynamic gold nanoparticles (AP-AuNPs), which are self-assembled nanocomposites of an antibacterial photodynamic peptide and poly(ethylene glycol) (PEG)-stabilized AuNPs. The AP-AuNPs exhibited aqueous and light stability, a satisfactory generation of reactive oxygen species (ROS), and a remarkable antibacterial effect toward both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli upon light irradiation. Moreover, the synthesized nanocomposites significantly inhibited bacterial growth and biofilm formation in vitro. Photodynamic antibacterial treatment accelerated the wound-healing rate in S. aureus infections, mimicking staphylococcal skin infections. Using a combination of the bactericidal effect of a peptide, the photodynamic effect of a photosensitizer, and the multivalency clustering on AuNPs for maximal antibacterial effect under light irradiation, we synthesized AP-AuNPs as a wound-dressing nanomaterial in skin infections to promote wound healing. Our findings indicate a promising strategy in the management of bacterial infections resulting from damaged skin tissue, an aspect that has not been fully explored by our peers.