It hasn’t proven easy to destroy COVID-19 in patients. But it is possible to destroy the new Coronavirus in the environment using ultraviolet LED (light-emitting diode) lights, which disinfect it in less than 30 seconds and can be installed in water, air-conditioning and vacuum systems and will soon be available for private and commercial use, according to say Tel Aviv University (TAU) researchers. 

Using UV-LED irradiation at different wavelengths 

Their study, just published in the Journal of Photochemistry and Photobiology B: Biology under the title “UV-LED disinfection of Coronavirus: Wavelength effect,” was the first in the world on the disinfection efficiency of a virus from the family of coronaviruses using UV-LED irradiation at different wavelengths or frequencies. 

It was headed by Prof. Hadas Mamane, head of TAU’s environmental engineering program at the School of Mechnical Engineering of the Fleischman Faculty of Engineering and conducted in collaboration with Prof. Yoram Gerchman of Oranim College, Dr. Michal Mandelboim (the director of the National Center for Influenza and Respiratory Viruses at Sheba Medical Center at Tel Has homer; and Nehemya Friedman at Sheba.

A length of 285 nanometers

SARS-CoV-2, the causal agent of COVID-19, is not only contagious through respiratory droplets, but can also spread through nasal, oral and eye mucus-contaminated surfaces, the team wrote “Moreover, it has recently been suggested that SARS-CoV-2 could be airborne, although clear evidence for such transmission has not yet been presented. Furthermore, SARS-CoV-2’s ability to survive in aerosols for at least 3 hours and up to 72 hours on plastic surfaces was recently demonstrated, suggesting long-term infection risks.”

In the study, the researchers tested the optimal wavelength for killing the coronavirus and found that a length of 285 nanometers was almost as efficient in disinfecting the virus as a wavelength of 265 nanometers, requiring less than half a minute to destroy more than 99.9% of the coronaviruses. 

Effective solutions to disinfect the coronavirus

This result is significant because the price of 285 nm LED bulbs is much cheaper than that of 265 nm bulbs, and the former are also more readily available. Eventually, as the technology progresses, the industry will be able to make the necessary adjustments and install the bulbs in robotic systems or air conditioning, vacuum, and water systems and thus be able to disinfect large surfaces and spaces efficiently. Mamane believes that the technology will be available for use in the near future.

“The entire world is currently looking for effective solutions to disinfect the coronavirus,” said Mamane. “The problem is that to disinfect a bus, train, sports hall or plane by chemical spraying, you need physical manpower and for the spraying to be effective, you have to give the chemical time to act on the surface. We know, for example, that medical staff do not have time to manually disinfect computer keyboards and other surfaces in hospitals, for example – and the result is infection and quarantine. The disinfection systems based on LED bulbs, however, can be installed in the ventilation system and air conditioner and sterilize the air sucked in and then emitted into the room.”

Patenting a combination of different UV frequencies

She continued that it was quite simple to kill the coronavirus using LED bulbs that radiate ultraviolet light. “But no less important, we killed the viruses using cheaper and more readily available LED bulbs, which consume little energy and do not contain mercury as do regular bulbs. Our research has commercial and societal implications, given the possibility of using such LED bulbs in all areas of our lives safely and quickly. Of course, as always when it comes to ultraviolet radiation, it is important to make it clear to people that it is dangerous to try to use this method to disinfect surfaces inside homes. You need to know how to design these systems and how to work with them so that you are not directly exposed to the light.”

Ultraviolet radiation is a common method of killing bacteria and viruses, and most of us are familiar with such disinfecting bulbs from their use in water purifiers, such as Tami4. UV radiation damages nucleic acids. Last year, a team of researchers led by Mamane and Gerchman patented a combination of different UV frequencies that cause dual-system damage to the genetic load and proteins of bacteria and viruses, from which they cannot recover-which is a key factor that is ignored.

“In the future,” concluded Mamane, “we will want to test our unique combination of integrated damage mechanisms and more ideas we recently developed on combined efficient direct and indirect damage to bacteria and viruses on different surfaces, air and water.”