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Uploaded:2020-11-02
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Masks do wonders to stop the spread of infection and inhalation of harmful particles, and some new technology can make them both more effective and easier to clean.

Hosted by: Hank Green

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Sources:
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Image Sources:
https://www.istockphoto.com/photo/happy-african-american-black-kid-in-medical-protective-face-mask-showing-thumb-up-on-gm1256690952-368044761
https://commons.wikimedia.org/wiki/File:1918_flu_outbreak_RedCrossLitterCarriersSpanishFluWashingtonDC.jpg
https://commons.wikimedia.org/wiki/File:Surgical_N95.jpeg
https://www.storyblocks.com/video/stock/pastry-chef-filling-silicone-molds-with-liquid-mousse-pouring-cake-into-silicone-mold-close-up-desserts-production-at-confectionery-hxc84fcv7jk9y0eqv
https://www.storyblocks.com/video/stock/woman-putting-on-surgical-mask-for-virus-prevention-szsww9wuik85zlymv
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[♪ intro].

Back in 1878, a physician named A. J.

Jessup argued doctors and nurses should wear cotton masks over their mouths and noses to prevent the spread of infections.  And to this day, masks remain an essential part of controlling infectious diseases like, for example, COVID-19.  But most of us are still using the same technology Jessup was. Even our best masks are kind of difficult to fit properly or reuse. Which is why scientists around the world are trying to develop some seriously next-level protective equipment—from indestructible masks to ones that clean themselves.

Cloth masks are great in many ways, but they’re not as effective at stopping viruses as N95 respirators. As the name suggests, those filter out ninety-five percent of the tiny airborne particles that can carry viruses and bacteria, while letting the air itself go right on through.   They work really well while still being breathable.  Trouble is, to achieve that ninety-five percent filtration, the masks have to create a tight seal with the user’s face.  And each mask is basically one-time use, because they’re really hard to sterilize.  The material is made of layers of super teeny fibers which use electric charges to trap droplets and microbes. And soapy water, cleaning products like bleach and ethanol, and high temperatures all seem to mess with those fibers.

So basically every usual sterilizing technique can ruin N95s after a couple rounds. And that’s one of the big reasons these masks are in such short supply.  To solve this problem, researchers from MIT and Brigham and Women’s Hospital are working on a silicone respirator they’ve dubbed the iMASC system. You might have some squishy silicone bakeware in your kitchen, because silicone can be baked, boiled, or even deep-fried without falling apart.

Well, that’s exactly the goal with iMASCs. They can be soaked in bleach or baked in the oven. You can clean them over and over any way you want.   The only catch is that they require a bit of N95 material to be inserted into slots in the front to work—and this material has to be replaced after every use.  But iMASCs use less than half the amount of filter as a traditional respirator.

So they could help extend the limited supply of N95 material. Of course, they’ll need additional testing to prove themselves before they hit the market.  And, while bakeable respirators would be a step up from use-and-toss ones, they still require sterilizing.  Other researchers are trying to make it so the masks sanitize themselves.  Like, researchers at the University of Central Florida are developing nanofilm coatings for masks and other kinds of protective equipment.  These are ultra-thin layers just a few atoms thick that pack a big functional punch. Or, I should say, a one-two punch.  As outlined in the group’s grant application, the goal is to first attack microbes with a layer of oxygen-containing nanoparticles.  These absorb the energy from natural light and then spit out ultraviolet light in the presence of certain substances.  So, the idea is any droplets that hit the mask will be irradiated by tiny bursts of virus-destroying UV light.    Then, to really make sure that the coating kills specific viruses, the researchers plan to add a layer of molecules that can bind to a virus’s outer surface, trapping infectious particles in place.  So, given the current pandemic, they’d have the coating target the virus behind COVID-19, to ensure that virus always gets zapped to death.  Other researchers think the best mask is one that keeps viruses from getting onto the mask material in the first place.  They’re betting on superhydrophobic materials: ones that are unbelievably good at repelling water.  You see, viruses hitchhike through the air on teeny droplets.

So, prevent droplets from clinging to a mask, and you can keep viruses from getting in.  That’s why researchers at Hong Kong Polytechnic University have been studying thin coatings of graphene.  It’s a form of carbon that could transform your everyday mask into one that viruses just bounce off of, because it changes the wettability of surfaces.  For most materials, when a watery substance hits it, the droplet gets squished and spreads out—in other words, the material gets wet.  Hydrophobic materials keep droplets spherical so they’re more likely to fall off. And it turns out ordinary surgical masks are somewhat hydrophobic. But once they’re coated in graphene, water literally bounces off of them—right off along with any viruses it might contain.  An added bonus of graphene is that it’s also super good at absorbing light.  So if droplets do manage to hold on, exposing a graphene-coated mask to good old sunlight for a few minutes heats it up enough to kill anything that might be lurking.  But it and other superhydrophobic substances may not be the best choice.  Weirdly enough, some researchers are taking a total opposite approach to self-sterilizing masks: they’re looking at superhydrophilic substances.

Substances that love water.  That’s because, in an August 2020 paper in Physics of Fluids, mathematical models suggested droplets thin out and dry faster on hydrophilic materials. And the faster a droplet dries, the faster any viruses inside die.   So, the next generation of masks may soak up airborne droplets instead of repel them! Or, they may simply be super rugged, so they can be bleached, boiled, or whatever to keep them clean.  But until these high-tech masks have undergone proper testing, we will have to keep using the ones we already have.  Luckily, our old-school masks can still do plenty of virus-stopping!

Plus, I'm starting to think they look kinda good. Like, you're looking at my whole face right now, and it's, like, weird. It's starting to feel weird.

Thanks for watching this episode of SciShow! And especially thank you to all of our patrons who support us on Patreon. Without them, we couldn’t make SciShow!  But also, we think our patron community is simply the best group of science-loving people out there. We have so much fun chatting with them on our patron Discord channels, and love hearing their ideas for episodes through our QQ inbox.  So if you’re the kind of person who wants to support free educational science content on YouTube and be a part of a nerdy community, you can learn more about becoming a patron at patreon.com/SciShow. [♪ outro].