Solar-excited graphene quantum dots for bacterial inactivation via generation of reactive oxygen species

Abstract

Nanoscale photocatalysts have attracted abundant research attention in the solar-activated disinfection. In this work, we find that solar irradiation significantly improves the antimicrobial activity of graphene quantum dots (GQDs), accompanied by severe oxidative stress and membrane damage. By using electron spin resonance (ESR) technique, we confirm that different reactive oxygen species (ROS), including singlet oxygen (¹O₂), hydroxyl radical (•OH), and superoxide anion (O₂^•−) were generated by GQDs upon irradiation with simulated sunlight. Additionally, these generated ROS will further facilitate lipid peroxidation of cell membrane and suppress bacterial antioxidant systems, enhancing the phototoxicity of GQDs. These findings will bring major advancements of GQDs in applications of solar-driven bacterial disinfection.

Keywords:

• Graphene quantum dots
• bactericidal effects
• ROS
• lipid peroxidation

Additional information

Funding

Y. Chong appreciates the Natural Science Foundation of Jiangsu Province (BK20170353) and Natural Science Foundation of the Jiangsu Higher Education Institutions of China (17KJB340002) for partial support. This work is also partially supported by Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).