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New bandages turn color to identify an infected wound

Smart bandages quickly identify antibiotic-resistant bacteria, and normal bacteria, in owies.

Image source: Di Studio/Shutterstock/Big Think
  • Judicious use of drugs for resistant bacteria requires time- and money-consuming tests until now.
  • New smart bandages turn red for resistant bacteria and yellow for antibiotic-sensitive bacteria.
  • The bandages also promote healing with the application of UV light.

The growing incidence of antibiotic-resistant bacteria was already a worrying problem before we all started washing our hands with anti-bacterial soaps in response to SARS-CoV-2. While necessary, we may also have provided even more bacteria the opportunity to develop resistance. Such uncooperative bacteria can often be treated, but before they can, they have to first be identified as antibiotic-resistant — each time the precious meds capable of defeating such bacteria are deployed, we risk bacteria developing resistance to them. This would obviously render them useless, and so they're administered only sparingly to bacteria that have tested as resistant. This testing takes time, and can be expensive.

Researchers at the Chinese Academy of Sciences, Changchun, Jilin province have a better idea: smart bandages that change color to indicate the nature of bacteria they cover. The study describing their research his published in ACS Central Science.

The idea behind the bandages

colored liquids being poured into beaker

Image source: Alex Kondratiev/Unsplash

The smart coverings work by leveraging the chemistry of bacterial infections. Integrated into each covering is a metal organic framework (MOF), a structure that allows scientists to embed a few key chemicals in the bandages.

The bandages contain a chemical called nitrocefin that breaks down in the presence of the enzyme β-lactamase — β-lactamase is the enzyme that resistant bacteria produce and use to neutralize antibiotics. It's essentially the chemical source of antibiotic resistance. When the nitrocefin interacts with β-lactamase, it breaks down and turns red — as does the bandage— signifying the presence of an antibiotic-resistant bacteria.

For detecting normal, antibiotic-sensitive bacteria, the bandages leverage the fact that a bacterial infection on your skin causes a reduction in its pH, making the skin more acidic. Each smart bandage contains a chemical called bromophenol blue, and when it encounters a more acidic environment, it turns yellow. Thus, when a smart bandage turns yellow, it's telling you that bacteria is present, but that it's antibiotic-sensitive.

If there's no infection, the covering remains its original green color.

Tests and cures

fluorescent light above mirror

Image source: Khamkhlai Thanet/Shutterstock

The bandages have so far been tested on mice who were infected with one of two different strains of E. Coli bacteria, one antibiotic-sensitive, and one antibiotic-resistant. The smart coverings over the mice's wounds behaved as designed, turning the hoped-for colors over the course of a day or two. After some tweaking, that time — and the identification of bacteria — was reduced to just 2-4 hours.

An additional feature is that the design of their MOF causes UV light shined on them to produce reactive oxygen species (ROS) that puncture the protective membranes surrounding the bacterial cells. This restores their susceptibility to standard antibiotics, meaning that the bandages are both diagnostic and curative.

Given the construction simplicity of the bandages, the researchers are hopeful that they can be easily manufactured at scale to join the fight against antibiotic-resistant bacteria, which is currently credited with 700,000 deaths annually.

Being able to quickly identify resistant bacteria can help prolong the effectiveness of available treatments. As the study puts it, "Because of the "auto-obsolescence" of antibacterial treatments, it is an important issue in the current antibacterial field how to rationally use of existing antibiotics and overcome tolerance."

The mystery of moving, mossy, ‘glacier mice’

Atop certain glaciers are herds of small mossy balls that somehow move together when no one's looking.

Image source: Carsten ten Brink/flickr
  • Weird but cute, "glacier mice" are actually balls of moss, dirt, and more.
  • The balls move, oddly, in packs through some unknown means.
  • A new study tracked 30 glacier mice but still couldn't figure out what's going on.

Scientists have known about them at least since the 1950s, when Jón Eythórsson named them "jökla-mýs," which translates as "glacier mice." However, they're not actually mice. They're smallish balls of moss, and there are lots of them atop Alaska's Root Glacier. They can also be found on ice in Iceland, Svablard, and even South America, presumably places with just the right conditions, though researchers don't know what those conditions are.

The really odd thing about them is that they apparently move in some unexplained way, though no one has observed them doing so. It's just that repeated visits find them in different places.

And that's not the coolest part. "The whole colony of moss balls, this whole grouping, moves at about the same speeds and in the same directions," geologist Tim Bartholomaus of University of Idaho (UI) tells NPR. "Those speeds and directions can change over the course of weeks."

Bartholomaus and two colleagues have published their research on glacier mice in Polar Biology.

Mice but not mice

Image source: Steve Coulson/ The University Center at Svalbard

The "glacier mice" nickname has stuck perhaps because glaciologists are so fond of the fuzzy things. They are pillow-like, soft, squeezable objects, comprised of different species of moss, but that is not all.

A 2012 study found entire thriving habitats inside the mice. "I had expected to find some animals, but not so many," said study author and arctic biologist Steve Coulsonto to the New York Times. His research revealed springtails (six-legged insects), tardigrades (of course), and simple nematode worms. In a single mouse, there were 73 springtails, 200 tardigrades, and 1,000 nematodes.

Co-author of the new study, wildlife biologist Sophie Gilbert of UI describes them:

"They really do look like little mammals, little mice or chipmunks or rats or something running around on the glacier, although they run in obviously very slow motion."

Clues and an unsolved mystery

Some glacier mice are found perched on ice pedestals.

Image source: Fanny Dommanget/The University Center at Svalbard

Her report recounts the efforts made by Bartholomaus and his co-authors, which also included biologist Scott Hotaling of Washington State University, to figure out how the mice are getting around.

The 2012 study outfitted some mice with accelerometers and confirmed that they do rotate, but that's as far as its authors went into the balls' means of travel.

For Bartholomaus and his cohorts, there were some clues going into this.

For example, occasionally, balls are found perched on a pedestal of ice as seen above, perhaps shading that spot from melting sunlight until it finally melts and the ball rolls away.

Another clue is the intact nature of the healthy moss that serves as each ball's surface — it's a sign that they all have their turn in the sun. "These things must actually roll around or else that moss on the bottom would die," says Gilbert.

One obvious explanation was quickly ruled out — they're not simply rolling downhill, because many of them were found to be on level surfaces.

For the study, the researchers tagged 30 of the mice with a loop of wire and colored beads that identified each ball. They tracked their position for 54 days in 2009, and again in 2010, 2011, and 2012.

Bartholomaus explains, "By coming back year after year, we could figure out that these individual moss balls were living at least, you know, five, six years and potentially much, much longer."

Although the researchers expect the movements of the balls would be individualized and random, that's not what they found. The balls moved about an inch a day, and together, like a herd of animals.

Also, they periodically changed direction. "When we visited them all, they were all just sort of moving relatively slowly and initially toward the south," Bartholomaus said. "Then they all started to speed up and kind of start to deviate toward the west. And then they slowed down again and progressed even farther to the west."

Wind, maybe? Measurements of the dominant winds in the area ruled that out. Sunlight patterns also failed to account for the movement of the packs.

So, what's going on? Admits Barholomaus, "We still don't know. I'm still kind of baffled."

Suggestions

Given scientists' affection for the little balls, other people are also rolling the idea around in their minds. Ruth Mottram of the Danish Meteorological Institute suggests to NPR, "I think that probably the explanation is somewhere in the physics of the energy and the heat around the surface of the glacier, but we haven't quite got there yet."

Another theory put forward is that the moss on a ball's underside grows and pushes it over and forward, cueing up the next moss to begin growing in the same way. If growth rates from ball to ball are similar, this could explain their herd-like movement.

The mystery is reminiscent of the "sailing stones" of Death Valley that perplexed scientists for years unit their secret was revealed: They're pushed around by the wind as they temporarily float on wet melting ground ice.

Ask a Chemist: How does handwashing kill coronavirus?

The physical action of handwashing plus the properties of soap is a one-two punch for the virus.

  • A common recommendation from experts to help protect against coronavirus is to wash your hands often, but why? It turns out that each time you do it is an effective two-pronged attack.
  • As Kate the Chemist explains, the virus has a weak outer membrane. By using the proper handwashing technique, you're actually breaking through that membrane and ripping the virus apart.
  • Soap is an important part of the equation because of its two sides: the hydrophobic side (which grabs onto the virus), and the hydrophilic side (which grabs onto the water). Washing your hands with soap for at least 20 seconds allows the virus to be rinsed away.

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Kate the Chemist: Water is a freak substance. Here’s why.

Dr. Kate Biberdorf explains why boiling water makes it safer and how water molecules are unusual and cool.

  • University of Texas professor and science entertainer Kate the Chemist joined Big Think to talk about water molecules and to answer two interesting and important questions: Why does boiling water make it safe to drink, and what happens to water when you boil or freeze it?
  • According to Kate, when water is heated to a certain temperature (100°C/ 212°F) the hydrogen bonds break and it goes from a liquid to a gas state. Boiling for a minimum of 5 minutes kills any viruses and bacteria that were in the water.
  • "Water is a freak and so it is one of my favorite molecules ever," Kate says. "It has these unique properties and we are surrounded by it constantly. We also are made of water. We have to drink water to survive...It's a really, really fun molecule to investigate."

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'Waterworld' was a documentary? Geologists think Earth could have once been 100% ocean

The Hollywood blockbuster may have been right, if only 3.2 billion years off the mark.

(Photo: Universal Pictures)
  • Researchers find evidence that Earth may have been submerged in a global ocean during the Archaean eon.
  • The research could change our understanding of how life emerged.
  • It's one of many recent studies changing how we view our planet's infancy.
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