It probably won’t come as much surprise to find that a blast of hot plasma can be used to sterilize a surface. Unfortunately, said surface is likely going to look a bit worse for wear afterwards, which limits the usefulness of this particular technique. But as it turns out, it’s possible to generate a so-called “cold” plasma that offers the same cleansing properties in a much friendlier form.
While it might sound like science fiction, prolific experimenter [Jay Bowles] was able to create a reliable source of nonthermal plasma for his latest Plasma Channel video with surprisingly little in the way of equipment. Assuming you’ve already got a device capable of pumping out high-voltage, all you really need to recreate this phenomenon is a tank of helium and some tubing.
[Jay] takes viewers through a few of the different approaches he tried before finally settling on the winning combination of a glass pipette with a copper wire run down the center. When connected to a party store helium tank and the compact Slayer Exciter coil he built last year, the setup produced a focused jet of plasma that was cool enough to touch.
It’s beautiful to look at, but is a pretty light show all you get for your helium? To see if his device was capable of sterilizing surfaces, he inoculated a set of growth plates with bacteria collected from his hands and exposed them to the cold plasma stream. Compared to the untreated control group the reduction in bacterial growth certainly looks compelling, although the narrow jet does have a very localized effect.
If you’re just looking to keep your hands clean, some soap and warm water are probably a safer bet. But this technology does appear to have some fascinating medical applications, and as [Jay] points out, the European Space Agency has been researching the concept for some time now. Who knows? In the not so distant future, you may see a similar looking gadget at your doctor’s office. It certainly wouldn’t be the first time space-tested tech came down to us Earthlings.
Just in time for a project at work that could use something like this.
Looks awful violet. Do you think it might have a lot of ultraviolet that it emits along with the visible light? That would explain the antibacterial effects.
https://en.wikipedia.org/wiki/Reactive_oxygen_species#/media/File:Free_Radical_Toxicity.svg
Helium can not be a free radical.
But the gas he’s pumping is 20% oxygen which can.
+1
The party balloon helium tank does contain 20% oxygen (probably too many Darwin awards if they did not). So makes you wonder if you just exposed the Petri dish to Ozone alone would that have the exact same effect. Or did not even use helium at all, just used an ioniser with the needle pointed directly at the Petri dish would that have the same effect. Oh, and maybe a control where they just flow helium (with the electrode powered off) over the Petri dish because the helium tank could have been cleaned with an antibacterial agent before being filled.
The problem with youtube is that the scientific method does not always produce visually appealing video.
It’s not about darwin awards, but money…helium is expensive.
Nope. It is about people passing out and the producer getting hammered in court.
If you have never passed out from inhaling too much helium you missing out. Its a great way to get a welt on your head and to freak out your parents.
Pause the video at 08:05 to read the answer: UV is thought to have only a minor effect.
I wonder how effective that might be for treating polyethylene, polypropylene, teflon, etc. prior to painting or adhesion. Getting paint or glue to stick on these surfaces is a PITA at the very least.
Yes, saw similar articles for cold plasma cleaning prior to applying gasket polymers to metals and plastics a while back.
https://www.pressebox.com/pressrelease/reinhausen-plasma-gmbh/Coldactive-plasma-sets-new-standards-in-the-surface-treatment-of-plastics/boxid/366058
Had a client who wanted just that.
In theory this will work. The plasma activates the surface, which makes paint and ink to stick to various plastics, which can then be further treated. The activation fades over time, and the next day it will be gone and you would need to retreat.
If you’re a manufacturer, you can purchase professional cold plasma systems (around $10,000, IIRC) that are very much like the one in the article, but with more robust electronics. These typically use Nitrogen instead of Helium, and use a microwave antenna at the tip (IIRC) to generate the plasma. If you’re with a company, you might be able to rent one of these for testing.
There’s lots of interesting manufacturing uses for these; for example, mist forms microscopic beads of water on a normal surface, but will spread out evenly on a treated surface.
I witnessed a demonstration of cold plasma some years ago, by putting my finger under it, weird sensation but not hot, I think dentists use it amongst others.
if you search the web for cold plasma, you find a lot medical purposes, even killig covid virus.
It’s possible that the mechanism of action is by creating reactive oxygen species, free-radicals etc. Anything capable of breaking chemical bonds might also be capable of causing harm in healthy tissue. Applications for sterilization of things that aren’t part of the human body make sense, and maybe use on unhealthy tissue/wounds etc in some circumstances if backed by clinical evidence. I wouldn’t want to use this in any kind of routine ‘cleansing’ or some kind of generic ‘healing’.
First impression is that helium is very unlikely to stay ionized as it cools. Even the gas in a neon sign is only partially ionized. Using oxygen to get ozone instead of helium will be a lot cheaper – because plain air will do the job. I wold check electronegativities and all that but I have to smoke a salmon.
Much better to use ozone. Far easier to make, especially if you’ve already got a high voltage power supply handy. It can me explosive in very high concentrations and despite the nice smell and the fact many a high voltage enthusiast has been breathing it for years, apparently it’s not all that good for you. But filling your house while you’re away and venting it when you get home will definitely kill a fair few bacteria.
Ultraviolet rays can create reactive oxygen species too. It may be one reason why third world countries didn’t get hit as hard by covid as some might have predicted. Since air conditioning is less common (and no building efficiency standards), the buildings are more open to outside airflow in those countries, thus better protection from respiratory illnesses.
In the tropics, cold and flu season happens when it rains, e.g. when it is cloudy, people may be indoors more often, but a more noticeable difference is less sunlight to create ozone.
I have read, professional, even medical cold plasma generators does not use neon, but xenon.
Right! My dentist had a cold plasma pencil, more than twenty years ago.