Ultraviolet radiation is a common method used for killing off bacteria and viruses, now researchers have demonstrated that it can also kill SARS-CoV-2 efficiently, quickly, and cheaply using ultraviolet light-emitting diodes at specific frequencies. Professor Hadas Mamane said that the UV-LED lighting required less than a half-minute to destroy over 99% of the coronaviruses.
The results from the first of its kind study have been published in the Journal of Photochemistry and Photobiology B: Biology. Since Mamane presented her work at the Boris Mints Institute 2020 Research Conference she has given many interviews and written about the successfulness many times.
LEDs are available in a range of wavelengths known as A, B, and C. UV-A has a wavelength in the range of 315-400 nanometers; UV-B has a wavelength of 280-315nm, and UV-C has a wavelength of 200-280 nm, explains Mamane.
UV-A is emitted by the sun and artificial sources but it is weaker than UV-B and C. It has some benefits like creating vitamin D in the skin, but this is also what causes sunburns and in some cases cancer. UV-B and C radiation typically never reach humans under natural circumstances because they are absorbed by the ozone layer, these are the wavelengths that the Tel Aviv researchers were investigating which are especially effective in disinfection using UV-LED bulbs.
“We know, for example, that medical staff do not have time to manually disinfect, say, computer keyboards and other surfaces in hospitals – and the result is infection and quarantine,” said Mamane. “The disinfection systems based on LED bulbs, however, can be installed in the ventilation system and air conditioner, for example, and sterilize the air sucked in and then emitted into the room.”
“We are also developing, together with a scientist in North Western University a transparent coating that can be dipped or sprayed on surfaces and can kill viruses using visible light LEDs that are not dangerous and are used everywhere, providing another application for regular LEDs,” adds Mamane.
Mamane and colleagues were able to kill the novel virus using cheaper and more readily available LED bulbs, 285 nm vs. 265 nm bulbs, which use little energy and do not contain mercury as do regular UV lamps. The team said that the 285 nm LED is 15-30% less expensive and requires very little more/extra time to be effective.
According to Mamane as the science develops the industry will be able to make the necessary adjustment to install bulbs into robotic systems, public transportation, air conditioning, vacuum, ventilation and water systems to efficiently disinfect large areas, surfaces and office/living spaces.
“Our research has commercial and societal implications,” Mamane said, explaining that UV LEDs have the advantage of being able to be turned on/off in an instant. “Anything that can reduce cost could help implementation,” she adds, concluding that this technology is now not just for the future, and she expects that by 2025 it will be well cost-effective enough to become mainstream globally.
“UV LEDs have a huge future,” she added. “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.”
