Antimicrobial and antiviral activities and reaction mechanisms of an organic photocatalyst upon visible-light irradiation

Organic photocatalyst 9,10-dicyanoanthracene (CN-anthracene) has been demonstrated to exhibit antimicrobial activity upon visible-light irradiation. By evaluating these dependencies, this research aims to clarify the underlying mechanisms of its photocatalytic action and provide insights into its practical applications in diverse antimicrobial scenarios. This study examined the light and temperature dependence of the antimicrobial activity of CN-anthracene to further investigate its photocatalytic properties in detail. The antimicrobial activity was evaluated using the colony count method with Escherichia coli (E. coli) as the target organism. The results indicated that the antimicrobial rate increased with the light intensity and that the antimicrobial activity was above a certain level regardless of the temperature in the expected indoor temperature range. The antiviral activity of the photocatalyst was investigated using a median tissue culture infectious dose (TCID₅₀) assay. The results showed that the photocatalyst exhibited high viral activity against both enveloped and non-enveloped viruses. Furthermore, the presence of reactive oxygen species (·OH and ·\({\text{O}}_{{2}}^{ - }\)), which are believed to play a critical role in the observed antibacterial and antiviral activities, was confirmed. These findings demonstrate that CN-anthracene exhibits high antibacterial and antiviral activities under visible light, highlighting its potential as a novel tool for combating infectious diseases.