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Cheaper LEDs can disinfect against COVID-19, Israeli scientists find

Tel Aviv University team behind discovery is working on self-cleaning surfaces, including laptop keyboard that kill germs with ultraviolet light every time lid is closed

Nathan Jeffay is The Times of Israel's health and science correspondent

UV disinfection being used to clean a laboratory (LeafenLin via iStock by Getty Images)
UV disinfection being used to clean a laboratory (LeafenLin via iStock by Getty Images)

Israeli researchers have found a way to significantly cut the cost of COVID-19-killing ultraviolet lights, and they are working on LED-embedded surfaces that clean themselves.

“We have discovered that it’s easier than previously imagined to disinfect from coronavirus using light, and we are already working on exciting applications for our findings,” Hadas Mamane, head of Tel Aviv University’s Environmental Engineering Program, told The Times of Israel.

As the world struggles to disinfect surfaces and public places, there is growing interest in the use of ultraviolet light, which has long had uses in fighting bacteria and viruses. It is not yet widespread in the coronavirus fight, but has been deployed, including in transportation via light-emitting robots.

Mamane’s team has made a breakthrough it hopes will expedite its rollout, namely finding that the desired effect can be achieved with higher-wavelength — or “less energetic” — LEDs than previously believed.

A boy wearing a face mask rides his bike next to a worker disinfecting a bench in Madrid on April 28, 2020, during a national lockdown to prevent the spread of the COVID-19 disease. (Gabriel BOUYS/AFP)

The team’s research has been published in the peer-reviewed Journal of Photochemistry and Photobiology B: Biology. The key finding is that LEDs emitting light with a wavelength of 285 nanometers were almost as efficient in disinfecting the virus as those with a wavelength of 265 nanometers, requiring less than half a minute to destroy more than 99.9% of the coronaviruses.

This result is significant because the cost of 285-nanometer LED bulbs is 30% lower than that of 265-nanometer bulbs, said Mamane. She predicted this will make ultraviolet cleaning more common in ventilation systems and air conditioners, and make it a common solution for public transportation and other uses, she said.

Hadas Mamane, head of Tel Aviv University’s Environmental Engineering Program (courtesy of Tel Aviv University)

“There are applications we are working on ourselves, which we hope will make a contribution to the COVID fight,” Mamane said.

“We are developing surfaces that have LEDs embedded in them, in a way that light shines and disinfection takes place when they aren’t in use,” she added, giving an example of a laptop keyboard that is cleaned with ultraviolet light when the computer lid is closed.

The LEDs, while less powerful than those currently used for disinfection, would still prove dangerous to humans and therefore should only be activated when people are away from the surface being cleaned, she stressed.

Mamane said: “The fact that UV kills viruses is not a new thing, and it is well-known. But what we have done is to produce the first study looking at the wavelength needed, also known as the frequency, to check exactly what level of energy is needed to kill the coronavirus. We hope the finding that less energetic LEDs than previously thought kill the coronavirus will make this technology more widespread.”

Ultraviolet light administered “inside the body” was famously pitched as a cure for COVID-19 by US President Donald Trump in April.

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