Light Irradiation of N-Doped Graphene Acid: Metal-Free Strategy Toward Antibacterial and Antiviral Coatings With Dual Modes of Action

The increasing emergence of antimicrobial resistance and the development of new infective viral strains represent a constantly growing threat. Metal-based nanomaterials have emerged as promising tools in the fight against bacterial and viral infections; however, the release of metal nanoparticles/ions in clinical applications may cause undesired side effects (allergies, systemic toxicity), reducing their practical use in antimicrobial treatment. Moreover, the metal-based nanoparticles possess predominantly antibacterial effects, while their antiviral efficiency remains controversial. Thus, the development of metal-free strategies enabling combined antibacterial/antiviral properties is a significant challenge. Here, we report a strategy based on light irradiation of nitrogen-doped graphene acid (NGA) possessing dual photothermal and photodynamic modes of action. The antimicrobial activity is activated through a clinically approved near-infrared (NIR) light source, and both viral and bacterial spreading can be hampered on the coating irradiation on a scale of minutes (5 to 10 min). The developed metal-free strategy reduced 90.9% and 99.99% for S. aureus and P. aeruginosa, respectively, as well as 99.97% for murine hepatitis virus. Importantly, this research represents a significant advancement in the development of safe, metal-free, and effective antimicrobial treatments. NGA coatings are safe for skin, showing no sensitization or irritation, and offer significant potential for advanced antimicrobial treatments.