Doctoral defence: Alexandra Nefedova "Oxide nanostructures as antiviral coatings for textiles"

On 14 November 2025 at 14.15, Alexandra Nefedova will defend her doctoral thesis "Oxide nanostructures as antiviral coatings for textiles" .

Supervisors:
Prof. Angela Ivask, University of Tartu
Dr. Alexander Vanetsev, University of Tartu
Prof. Vambola Kisand, University of Tartu

Oponent:
Dr. Nadiia M. Zholobak, Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine

Summary

As recently evidenced, viral infections may have severe socioeconomical consequences. The disease-causing viruses may be transmitted between their hosts either through intermediate carriers, in aerosol droplets, via host to host contact or via surface deposition. The main transmission route differs between viruses but none of the routes should be fully excluded. This study focused on viral infection transfer via surfaces with a final goal to suggest an antiviral coating for soft surfaces like textiles. Development of textiles with antimicrobial properties is especially compelling since soft surfaces are more difficult to clean and at the same time pathogens can persist on them for a long time. Antiviral textiles have an application potential in healthcare, food industry, but also in public areas, especially in those involving vulnerable groups − schools, kindergartens and elderly care facilities. In this work metal oxide nanostructures were used to provide antiviral textile coating and real application relevant methods, where viruses were exposed to textiles in small droplets, were used to assess the antiviral activity. The prospective metal oxide nanostructures – cerium oxide and loaded mesoporous silicon dioxide, were selected based on earlier indications on their potential antiviral activity.

We demonstrated that although cerium dioxide nanostructures exhibited specific and rather good antiviral activity in colloidal form due to direct oxidation of amino acids in viral proteins, then after coating onto textile fibers, the activity was lost. We suggest that this was due to low water content of cerium oxide in the used semi-dry application relevant exposure conditions. Another metal oxide nanostructure, silica nanocontainer with quaternary ammonium compound CTAB, showed antiviral activity in both colloidal form and on textile surface. We suggest that its activity in semi-dry textile exposure was due to water entrapped in the pores of the silica nanostructures. As textile treatment, also copper nitrate exhibited antiviral properties, however in contact with water this surface coating was almost fully removed and therefore, could not be considered a stable antiviral coating for textiles. Therefore, our study highlighted that in order to achieve antiviral activity for textiles in semi-dry, application relevant conditions, certain level intrinsic moisture is needed. For prolonged antiviral effect the coating material should be minimally released from the textile surface. Among the materials studied here, only CTAB-loaded silica nanostructures fulfilled both of those requirements and could be considered for further development.