Visible Light Activation of Virucidal Surfaces Empowered by Pro-Oxidant Carbon Dots

The scientific community is actively engaged in the development of innovative nanomaterials with broad-spectrum virucidal properties, particularly those capable of producing reactive oxygen species (ROS), to combat upcoming pandemics effectively. The generation of ROS capable of inhibiting viral activity on high-touch surfaces can prove an effective means of reducing pathogenic and viral infections, while avoiding the exacerbation of antibiotic resistance resulting from the extensive use of chemical disinfectants. Carbon dots (C-dots), in particular, are a class of nanomaterials that under specific conditions is able to generate reactive species. They are, therefore, excellent candidates for fabricating light-activated functional antiviral devices. Pro-oxidant C-dots have been developed via microwave synthesis using an amino acid, glycine (Gly), and 1,5-diaminonaphtalene (DAN) as precursors. The formation of C-dots has been obtained by reacting the precursors in microwave using two different acid catalysts, H3BO3 or HCl. The HCl catalyst promotes the formation of a copolymer while using H3BO3 the precursors preferentially self-condense. The boron-catalyzed samples have shown to contain radical centers whose intensity increases upon illumination by UV and also visible light. They also show the capability of generating singlet oxygen through energy transfer to oxygen molecules when irradiated. The C-dots exhibit effective virucidal activity and have been tested in vitro using two different variants of SARS-CoV-2, the original strain, and Omicron. Antiviral C-dots have been finally used to functionalize a model surface, inducing a strong virucidal activity against the SARS-CoV-2 coronavirus with both ultraviolet (UV) and visible (VL) light. Carbon dots capable of emitting singlet oxygen under visible or UV light excitation are effective antiviral nanoparticles. The Carbon dots have a strong virucidal activity against different variants of SARS-CoV-2 and can be grafted on high-touch surfaces. image