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265nm lasers for SARS-CoV-2

Eddie H

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I've been wondering if perhaps there should be arrays of "cancer ray" lasers fitted to drones for low risk sterilisation of commonly touched surfaces.
It's just a seed of a thought in my mind and I have no way at all to try this myself but figured it was worth a discussion on here to guage the feasibility of such an idea.
Obviously this end of the spectrum is incredibly hazardous (wouldn't work if it wasn't!), and there are obvious drawbacks, like the fact it only works in line of sight.
Are there any pro/cons to this besides the obvious?
During this pandemic I think we should be hitting this virus with everything we've got.
Stay safe folks!
 



lasersbee

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Good idea... but I wouldn't use a drone fitted with Lasers that
emit UVC radiation due to the risk of human health.
I've recently purchased UVC LED lights to disinfect incoming
mail and courier packages in a dedicated box with a turntable.
Hopefully this will kill any virus that could still be viable on
any packages.

Jerry
 
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Eddie H

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Yeah, if the drone idea was to be put into use it would maybe have to be set times, like when supermarkets close the drones could do a sweep of the stores, etc.
As yet I've been using I.P.A on all incoming packages, does make the ink on labels run, etc. I've also been running an HV arc to pump a box full of ozone in which incoming things can sit that can't survive alcohols.
These are testing times we live in!
 

kecked

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I thought this with a 1khz 25uj 266nm laser and a set of scanners but I don’t see it being able to deliver the energy needed without a pretty long dwell time. The leds make more sense. What I do with mail is grab it with gloves and look at it outside. If I have to open I do It outside and then leave in my garage for three days. Fortunately I do all my bills online. Everything else can wait. I wash all my groceries cans bags and also let sit. I have a shoe bath I use when I come out of the car. Jackets stay outside. I change cloths as soon as entering the house and take a shower. Basically treating this like working at a bio lab. Purell hands as soon as I get back to car. Trying to use zero cash. Bet you could iron it. Credit card gets cleaned too. A month ago I’d call myself insane.
 

gazer101

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I would assume several hours of exposure would be needed... might as well nuke the surface with a '44 and have the heat disinfect it
 

paul1598419

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Yeah, the 266nm UV lasers are all 4th harmonic converted from 1064nm. Those wouldn't be very useful for disinfection as they are pulsed and take a great deal of energy to produce much less energy pulses of the 266nm UV. The LEDs seem to be a better alternative. But, don't discount bleach or alcohol as disinfection agents.
 

Encap

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Yeah, the 266nm UV lasers are all 4th harmonic converted from 1064nm. Those wouldn't be very useful for disinfection as they are pulsed and take a great deal of energy to produce much less energy pulses of the 266nm UV. The LEDs seem to be a better alternative. But, don't discount bleach or alcohol as disinfection agents.
Exactly, not a viable soloution for many reasons.

Here is an article on a more rational potential help/solution:
UV Sterilization: Far-UVC light kills airborne flu viruses without danger to humans
Use of overhead far-ultraviolet C light in public spaces could provide a powerful check on seasonal influenza epidemics, as well as influenza pandemics: https://www.laserfocusworld.com/las...airborne-flu-viruses-without-danger-to-humans
 

hwang21

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Pro tip: 70-80% ethanol (ethyl alcohol) is the most effective against encapsulated viruses like coronavirus - but 30 seconds of immersion is just barely enough to destroy the bare virus. If there's anything like oils/grease/mucus, the denaturing effect of alcohol is greatly reduced - it can take 4+ minutes to destroy the viruses using alcohol. Also, 60-90% alcohol concentration is ideal - >90% concentrations reduce the effectiveness of the alcohol. Lastly, in general, ethanol > isopropyl > methanol for disinfection purposes
 

gazer101

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Pro tip: 70-80% ethanol (ethyl alcohol) is the most effective against encapsulated viruses like coronavirus - but 30 seconds of immersion is just barely enough to destroy the bare virus. If there's anything like oils/grease/mucus, the denaturing effect of alcohol is greatly reduced - it can take 4+ minutes to destroy the viruses using alcohol. Also, 60-90% alcohol concentration is ideal - >90% concentrations reduce the effectiveness of the alcohol. Lastly, in general, ethanol > isopropyl > methanol for disinfection purposes
Why does >90% reduce effectiveness?
 

paul1598419

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Soap and water are as effective at denaturing this virus as anything else is. The viral coat is lipid based, so any soap or detergent will destroy it. Use cold water when you wash as that will help with keeping your skin hydrated. I use Dial soap. ;)
 

kecked

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Why is 90% less effective...ok couple things here. One no water no gradient to drive dehydration.
some bacteria and maybe virus. Don’t know when exposed to really serious attacks form seriotypes that don’t kill the organisium. It just hides till better conditions. An example is the Lform. When you use strong bleach the outer membrane is charred. The inside remains. When better conditions return it rebuilds the membrane and moves on. Can that occur in virus...maybe. If the rna survives sure. I think it’sthe dehydration denaturing in this case. This is a guess.....
 

paul1598419

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I believe you are talking about some bacteria that are spore forming. Those do have a hard shell casing that the bacteria is terminal, at one end of the spore, or central, closer to the middle. This only pertains to certain types of bacteria and no viruses.
 
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Why is 90% less effective...ok couple things here. One no water no gradient to drive dehydration.
some bacteria and maybe virus. Don’t know when exposed to really serious attacks form seriotypes that don’t kill the organisium. It just hides till better conditions. An example is the Lform. When you use strong bleach the outer membrane is charred. The inside remains. When better conditions return it rebuilds the membrane and moves on. Can that occur in virus...maybe. If the rna survives sure. I think it’sthe dehydration denaturing in this case. This is a guess.....
This is really cool, I’m an IRL virologist so it’s fun having a thread I can contribute to! You’re correct about the water gradient driving dehydration, but in the case of viruses, no they don’t have the ability to “sporulate” - viruses rely on their hosts, outside of a host cell they’re a dormant particle. If you destroy or damage the viral envelope, they’ll be unable to enter a new host which would be necessary for them to “repair” the envelope (if that were even possible). Viruses sometimes seem kind of spore like because they’re extremely tough - a good way to think about it is that bacteria that form spores are trying to behave like viruses as much as they can; shutting off active function and being dormant.

As for the main post of this thread: awesome concept! But as other astute commenters have pointed out, there are a couple practicality issues. I’m on my phone so I can’t see them as I type, so there will definitely be redundancy:

a)Effectiveness <MOST IMPORTANT>: UV light is totally anti microbial and CAN inactivate viruses. But the way UV light works to damage microbes is by causing a reaction between adjacent thiamine bases (the T in the ATCG code of DNA) to form “thiamine dimers” that are a form of genetic damage. However, coronaviruses are RNA viruses, which do not have thiamine, instead, they have uracil. Uracil CAN still form dimers, but only in the case of double stranded RNA (dsRNA) and coronavirus has single stranded RNA (ssRNA) which would make UV light MUCH less effective.

b) Efficiency: viruses are really really REALLY small. Electron microscope small. (The “laser microscopes” from my name are for looking at infected cells, can’t see the virus directly!) and as such, you’re better off hitting a large area with sterilization. The unique qualities of lasers aren’t so suitable here, a bank of LEDs would work better. Imagine a laser is a scalpel, LED’s are lawnmowers and your job is to cut the grass ;)

c)General: I love that people here think to use UV light as an anti-microbial. I use it at my lab all the time and I’m one of the biggest proponents of using it. The issue is that these things take time. As explained above, the UV light is initiating a chemical reaction, and more powerful light only speeds that up to a point. The key is TIME. Long exposures to the UV. That’s why at my lab I use UV lights to sanitize hoods before and after I use them to make sure there are no bacteria contaminating my workspace, and this works because I can turn on the UV lamp and leave it on while I get other things ready.

TL;DR: great idea, but UV light isn’t the best answer here for physics and biochemistry reasons. That said, send in the 60% alcohol drone army and I will accept my new robot overlords with open arms.

Awesome thread! Stay healthy everyone, soap, sanitizer and social distancing!
 

WizardG

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So for sterilizing wide areas we need a more efficient source of UVC. What about filtering the raw output of HID bulbs? I know that if the outer bulb of a metal halide or HPS lamp gets broken the raw output from the inner capsule is pretty profoundly dangerous due to the high levels of UV. But is there enough UVC of the appropriate wavelength to make this even close to practical, if there was an appropriate filter to block the wavelengths that would otherwise cook our eyes and skin? Could the mix of metals in a metal halide lamp be tweaked to maximize the output of the useful wavelengths?
 




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