‘An underutilized tool:’ UV-LED lights can kill coronaviruses and HIV with the flip of a switch – EurekAlert

April 17, 2022 by No Comments

image: Christina Guzzo conducted her research in the Guzzo Lab, a viral immunology lab at U of T Scarborough that focuses partly on HIV
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Credit: Ken Jones

The same lightbulbs used in offices and public spaces can destroy coronaviruses and HIV, according to a new study from U of T Scarborough.

Researchers killed both viruses using UV-LED lights, which can alternate between white light and decontaminating ultraviolet (UV) light. With a cheap retrofit, they could also be used in many standard lighting fixtures, giving them a “unique appeal” for public spaces, says Christina Guzzo, senior author of the study.

“We’re at a critical time where we need to use every single possible stop to get us out of this pandemic,” says Guzzo, an assistant professor in the department of biological sciences. “Every mitigation strategy that can be easily implemented should be used.”

UV lights kill viruses through radiation. Guzzo, alongside PhD students Arvin T. Persaud and Jonathan Burnie, first tested the lights on bacterial spores notorious for their resistance to this radiation (known as Bacillus pumilus spores).

“If you’re able to kill these spores, then you can reasonably say you should be able to kill most other viruses that you would commonly encounter in the environment,” says Guzzo, principal investigator at the Guzzo Lab.

Within 20 seconds of UV exposure, the spores’ growth dropped by 99 per cent.

The researchers then created droplets containing coronaviruses or HIV, to mimic typical ways people encounter viruses in public, such as from coughing, sneezing and bleeding. The droplets were then exposed to UV light and placed in a culture to see if any of the virus remained active. With just 30 seconds of exposure, the virus’ ability to infect dropped by 93 per cent.

Upon testing the viruses at different concentrations, they found samples with more viral particles were more resistant to the UV lights. But even with a viral load so high Guzzo calls it “the worst-case scenario,” infectivity dropped 88 per cent.

Though it wasn’t included in the study, Guzzo and her students also compared UV light to two heavy duty disinfectants used in lab research. They found the lights were similarly effective in their ability to deactivate viruses.

“I was really surprised that UV could perform on the same level of those commonly used lab chemicals, which we regard as the gold standard,” she says. “That made me think, ‘Oh, my gosh, this is a legitimate tool that’s really underutilized.’”

Balance UV’s pros and cons with clever use, researchers say

While the lights still left a small percentage of the virus viable, Guzzo references the “Swiss cheese model” of defence against COVID. Every strategy to fight the spread has its holes, but every layer is another chance to stop straggling virus particles.

Repeated exposure to UV light is key to catching those missed particles – fortunately, it’s as easy as flipping a switch. It’s also simpler to change a lightbulb than an air filtration system. Guzzo notes that UV-LEDs are cheap and could be easy to retrofit in existing light fixtures, and that the bulbs are long-lasting and simple to maintain.  

“You could disinfect in a way that wouldn’t be infringing on people’s enjoyment of that everyday ‘normal’ life that they long for,” Guzzo says.

The lights also …….

Source: https://www.eurekalert.org/news-releases/948073


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