A D V A N C E D M A T E R I A L S & P R O C E S S E S | J U L Y / A U G U S T 2 0 2 1 3 0 specific kind of virus) is placed on a material. Then a polymer film (serving as a cover) is positioned over the solution. After a certain amount of time, culturing is stopped in an incubator at a specified temperature. Next, the film and specimen are washed out into a petri dish and the washed-out solution is inoculated into a cellular culture. After cultivation takes place for a certain amount of time at a set temperature, the plaque forms are counted. From this, the infectivity of the material is determined. This assay and the corresponding evaluation method for the antiviral characteristics of materials (particularly polymeric materials) are standardized as ISO 21702. The Society of International Sustaining Growth for Antimicrobial Articles (SIAA)[9] organized various committees and investigated the effectiveness of this method. After the ISO standard was established, SIAA created a certification mark and began to certify the quality of antiviral characteristics of different products in July 2019 (Fig. 6)[10]. The assay does not always indicate that the viral infectivity of a material (as obtained by these methods) is the index for human infection. The direct relationship between these variables requires further research. However, this assay could be used to determine how long viruses on material surfaces retain their potential to infect people. Therefore, the development and use of this method continues to be of significant interest. ~AM&P Lead image: 2019-nCoV spike protein, courtesy of Jason McLellan/ University of Texas at Austin. For more information: Hideyuki Kane- matsu, professor of materials science and engineering, National Institute of Technology (KOSEN), Suzuka College, Japan, kanemats@mse.suzuka-ct.ac.jp. References 1. H. Kanematsu, R. Kawai, and R. Satoh, Antibacterial, Antiviral and Antibiofilm Coatings, The Journal of Japan Thermal Spray Society (JTSS), Vol 57, p 183-190, 2020. 2. A.W.H. Chin, et al., Stability of SARS-CoV-2 in Different Environmental Conditions, The Lancet Microbe, Vol 1(4), 2020. 3. G. Lee and P. Bishop, Microbiology and Infection Control for Health Professionals, 6th Ed., Pearson, 2015. 4. P.N. Barrett, et al., Determination of the Inactivation Kinetics of Hepatitis A Virus in Human Plasma Products Using a Simple TCID50 Assay, J. Med. Virol., Vol 49(1), p 1-6, 1996. AUTHOR SPOTLIGHT: HIDEYUKI KANEMATSU Hideyuki Kanematsu is a professor of materials science and engineering at the National Institute of Technology (NIT) (KOSEN), Suzuka College in Japan. His research focuses on how to measure and control the infectious capability of material surfaces. Kanematsu and his team concentrate on the interaction between materials and microbes in different settings, from healthcare and food sanitation to corrosion and power generation. Kanematsu received his country’s Minister of Education, Culture, Sports, Science, and Technology Award in early May, considered the number one prize from the Minister of Education in the Japanese government. He is a longtime member of ASM and currently serves on the AM&P Editorial Committee and the International Materials Reviews Committee. 5. L. Svensson, A. Hjalmarsson, and E. Everitt, TCID50 Determination by an Immuno Dot Blot Assay as Exemplified in a Study of Storage Conditions of Infectious Pancreatic Necrosis Virus, J. Virol. Methods, Vol 80(1), p 17-24, 1999. 6. J.J. Holland and L.C. McLaren, Improved Method for Staining Cell Monolayers for Virus Plaque Counts, J. Bacteriol., Vol 78(4), p 596-597, 1959. 7. W.C. Russell, A Sensitive and Precise Plaque Assay for Herpes Virus, Nature, Vol 195, p 1028-1029, 1962. 8. H. Kanematsu, A New International Standard for Testing Antibacterial Effects, Advanced Materials & Processes, Vol 175, p 26-29, 2017. 9. The Society of International Sustaining Growth for Antimicrobial Articles (SIAA), https://www.kohkin. net/en_index.html. 10. Y. Imoto, Antiviral Testing Method for Nonporous Materials, Journal of The Surface Finishing Society of Japan (SFSJ), Vol 72, p 269-272, 2021. Fig. 5 — Film covering method for antiviral evaluation. Fig. 6 — SIAA certification mark for antibacterial materials.
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