Nanobiotechnology for health-care
Photodynamic treatment of titanium dioxide nanoparticles is a convenient method of viral inactivation

Zahorodnia S.D.1, Povnitsa O.Y.1, Artiukh L.O.1, Zahornyi M.M.2, Ievtushenko A.I.2
1D. K. Zabolotny Institute of Microbiology and Virology of the NAS of Ukraine 154, Zabolotny str., 03143, Kyiv, Ukraine, 
E-mail: zagorodnya.sveta@gmail.com

2I. M. Frantsevich Institute for Problems of Materials Science, NAS of Ukraine, 3, Krhizhanovsky st., 03142, Kyiv, Ukraine, E-mail: earsen@ukr.net

     The search for safe substances for humans and the environment and ways to inactivate pathogens is one of the priority areas of research. It is known that under the action of UV radiation, mesoporous titanium dioxide (TiO2) produces active oxygen-containing radicals that can damage biological molecules of pathogens. Photodynamic inactivation is already used to inactivate enveloped viruses such as human herpes simplex virus, vesicular stomatitis virus, human immunodeficiency viruses, and hepatitis B and C viruses.
      In this study, we evaluated the possibility of using photodynamic ultraviolet treatment of synthesized titanium dioxide nanoparticles to inactivate human adenovirus type 5 (HAdV5). Adenoviruses are known to be very resistant to ultraviolet radiation. The suspension of TiO2 in aqueous-glycerol solution (concentration 10 mg/ml) was irradiated with UV light (BactoSfera OBB 15P OZONE FREE, Ukraine) at a distance of 20 cm, a wavelength at the peak 254 nm, power 15 W, peak - 4.5 W for 0, 5, 10, 20 and 30 minutes. Virus-containing material with a titer of 5.0 log10 TCID50 / ml was added to the nanoparticles, a series of 10-fold dilutions was prepared, and Hep-2 cells were infected. After 3-4 days of cultivation using MTT analysis, virus titers were determined. Inactivation of adenovirus by UV-photoactivated nanoparticles led to a decrease in virus titer by 4.5 log10 after 5 min of irradiation. 
    Thus, we have shown that the virus without the enveloped – HadV5 can be effectively inactivated by photoactivated titanium dioxide.