Search for new antiviral substances, development of modern antiviral preparations and disinfectants is an important area of modern science. Nanoparticles (NPs) and nanomaterials (NMs) receive increasing attention of scientists as promising antiviral substances recently. An aim of our study was to investigate antiviral activity of citrate-stabilized titanium nanoparticles (Ti NPs) against Teschovirus A (TV-A) and Potato virus Y (PVY). Refreshment, accumulation and purification of TV-A strain Dniprovskyi 34 has been performed. Titer of the virus was 6.46 lg TCD50/cm3. The virus has caused cytopathic effect (CPE) in transferable culture of embryonic pig kidney cell line (EPKT) after 24-72 h, which manifested as degenerative changes in cell culture, appearance of single spherical cells with further increase of their number until complete destruction of monolayer. There were no different types of CPE. Biological activity of PVY has been tested using cultivated tobacco plants (Nicotiana tabacum L.) and bell pepper plants (Capsicum annuum L.). It has been found that inoculation of plants with the virus has led to the appearance of PVY infection symptoms with further death of the plants. The presence of PVY has been confirmed by visual observation, serological analysis and transmission electron microscopy (TEM) of samples. It has been found that threshold limit value (TLV) for Ti NPs in EPKT cell culture is 12.5 µg/cm3. Higher concentrations cause degenerative changes in cell culture: disruption of monolayer’s integrity; rounding, flatness, corrugation, vacuolization and granularity of cells; changes in the color of medium, etc. It has been found that Ti NPs has no oral toxicity in mice at the concentration of 2,000 mg/kg. According to the prophylactic and treatment plots Ti NPs have slight antiviral activity against TV-A strain Dniprovskyi 34, decreasing its titer according to both plots by 0.5 lg TCD50/cm3. However, according to the virucidal plot at TLV concentration Ti NPs show high antiviral activity against TV-A strain Dniprovskyi 34, significantly decreasing its titer in EPKT cell culture by 4.46 lg TCD50/cm3. Therapeutic index (TI) for Ti NPs is 10. Virucidal activity of Ti NPs depends on exposition and is the highest after 24 h. Ti NPs does not have antiviral activity against PVY according to the prophylactic and treatment plots. However, according to the treatment plots. Nevertheless, according to the virucidal plot Ti NPs showed high antiviral activity against PVY, inactivating the virus in the reaction mixture in vitro. According to the results of TEM Ti NPs bind to virus particles. Virus particles with NPs attached to them, deformed and partially destroyed virus particles have been found in samples of virus-containing suspension, which were incubated with Ti NPs. Possible mechanisms of TV-A and PVY viruses inactivation by Ti NPs can include formation of system “virus-nanoparticle” due to the action of local fields; influence of local fields on spatial conformation of capsid proteins and their possible destruction; binding of NPs to disulfide bonds of capsid proteins and thiol groups of cysteine residues, which impairs or disrupts the entrance of the virus into susceptible cells; generation of reactive oxygen species (ROS), which damage virus particles. We suppose suggest that Ti NPs are useful as disinfectants to control viral infections, particularly TV-A and PVY.
Key words: Nanoparticles, Viruses, Virucidal activity, Microorganisms
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