Kaiming Ye et Guy German de l’Université de Binghamton, Université d’État de New York, ont mis au point une machine permettant de désinfecter les équipements de protection individuelle tels que les masques. Crédit : Université de Binghamton, Université d’État de New York.
La recherche jette les bases de normes sanitaires sur ce qui offre une véritable stérilisation par ultraviolets.
Lorsque le COVID-19 pandemic emerged in early 2020, ultraviolet (UV) radiation became one of the go-to methods for preventing the spread of the SARS-CoV-2 virus, along with facemasks, hand sanitizer, and social distancing.
One problem: There was little research showing what UV dosage kills the virus. What wavelength? How long? And could UV systems be installed in public places such as airports, bus terminals, train stations, and stores without causing long-term harm to people?
In a newly published research study, scientists from Binghamton University’s Thomas J. Watson College of Engineering and Applied Science answer many of those questions and lay the foundation for health standards about what offers true disinfection.
The paper, titled “Systematic evaluating and modeling of SARS-CoV-2 UVC disinfection” and published in the journal Scientific Reports, was written by Distinguished Professor Kaiming Ye, chair of the Department of Biomedical Engineering; BME Associate Professor Guy German and BME Professor Sha Jin, along with PhD student Sebastian Freeman; Zachary Lipsky, PhD ’21; and Karen Kibler from the Biodesign Institute at Arizona State University.
L’idée de cette recherche est née lorsque la pénurie d’équipements de protection individuelle (EPI) au début de la pandémie a incité les membres du personnel de Ye, German et de l’université de Binghamton à construire rapidement des stations de désinfection par UV pour les hôpitaux de la région, afin que les masques N-95 et d’autres articles puissent être réutilisés.
“Il y a beaucoup de recherches sur les dosages d’UV dans la littérature scientifique, mais pas de manière systématique”, a déclaré Ye. “Lorsque nous avons commencé ce projet, il n’y avait vraiment aucune donnée ou expérience qui avait été faite parce que la pandémie s’est produite très rapidement.”
Ye et German ont reçu un financement pour poursuivre leurs questions grâce à une subvention de mi-2020 de 182 728 dollars de la National Science Foundation. L’équipe de Binghamton a ajouté un rétrovirus similaire au CoV-2 du SRAS à trois milieux différents (un milieu de culture cellulaire, de l’eau et une recréation artificielle de salive humaine) et les a exposés à trois longueurs d’onde différentes dans la gamme des UVC. Les UVC tuent les virus et autres micro-organismes en endommageant leur DNA and RNA, which are the bioorganic building blocks for life.
Associate Professor Guy German, left, and Distinguished Professor Kaiming Ye, chair of the Department of Biomedical Engineering, have new research that offers provable standards for ultraviolet disinfection. Credit: Jonathan Cohen.
“The disinfection efficiencies are greatly influenced by the media where the virus is,” Ye said. “We used the same dosage, the same light intensity, and the same wavelengths when the virus was suspended in saliva, water, and a cell-culture medium, but the efficiency was completely different.”
The best results during the study came from a range of 260 to 280 nanometers, which is commonly used in LED UVC lights. Wavelengths below 260 nanometers can be deployed only in unoccupied spaces because they can damage human skin and eyes.
“There are so many companies that are purporting to say their products completely disinfect and are completely safe,” German said. “However, in this article, we demonstrate that both far (222 nanometers) and regular UVC light (254 nanometers) degrade the mechanical integrity of the stratum corneum, the skin’s top layer, causing higher likelihood of cracking. That means nasty bacteria and other microorganisms can get into and potentially infect your skin.”
Based on the results of the research, Ye and German have designed an LED light disinfection system that should cause less damage to human skin. They are doing additional testing before applying for a patent on it.
“We are waiting for the data, and then we are pretty much finished. We know it will work,” Ye said.
Also, the Binghamton team found that two amino acids (L-tryptophan and L-tyrosine) and a vitamin (niacinamide) are strong absorbers of UVC, and that discovery could lead to lotions that would block exposure and prevent skin damage if UVC disinfection becomes more prevalent in public spaces.
Ye believes the most important part of this research is that it offers a scientific basis for standardizing and regulating claims from manufacturers of UV disinfectant devices.
“The system we came up with can become the model for anybody who wants to standardize the dosage,” he said. “This is how to determine the eradication of SARS-CoV-2 using UVC — maybe also SARS-CoV-3, SARS-CoV-4, SARS-CoV-5. We hope we never get there, but we need to be prepared.”
Reference: “Systematic evaluating and modeling of SARS-CoV-2 UVC disinfection” by Sebastian Freeman, Karen Kibler, Zachary Lipsky, Sha Jin, Guy K. German and Kaiming Ye, 7 April 2022, Scientific Reports.
DOI: 10.1038/s41598-022-09930-2
