Researchers are figuring out ways to build structures out of microorganisms and fungi — for use both on Mars, where they could give astronauts a place to stay, and here at home, where they’ll help address the climate crisis. Plus: a Trojan horse treatment for cancer, and more, in this week’s coolest scientific advances.
What is it? Engineers at the University of Colorado Boulder marshaled “some of the tiniest contractors out there” into a new kind of building material: They designed bricks that incorporate living microorganisms.
Why does it matter? According to UC Boulder, living structures could heal their own cracks, purify the air or even be made to glow — if glowing buildings happen to be your thing. But the stakes are bigger than any single building: The creation of construction materials, namely cement and concrete, contributes significantly to global warming. The materials designed in the lab of engineer Wil Srubar, by contrast, remove carbon dioxide from the air. And they reproduce. “We know that bacteria grow at an exponential rate,” Srubar said. “That’s different than how we, say, 3D-print a block or cast a brick. If we can grow our materials biologically, then we can manufacture at an exponential scale.”
How does it work? Here’s how Boulder explains it: “The researchers inoculate colonies of cyanobacteria into a solution of sand and gelatin. With the right tweaks, the calcium carbonate churned out by the microbes mineralizes the gelatin which binds together the sand — and, presto, a brick.” Srubar likens it to making rice crispy treats, “where you toughen the marshmallows by adding little bits of hard particles.” He and his colleagues explain the process in slightly more scientific language in the journal Matter.
What is it? Are earthbound cyanobacterial habitats a little too … normal for you? Fear not. In hopes of giving its astronauts a place to stay when they rocket off to the moon, Mars or beyond, NASA scientists are researching “myco-architecture”: structures made from fungus.
Why does it matter? “Right now, traditional habitat designs for Mars are like a turtle — carrying our homes with us on our backs — a reliable plan, but with huge energy costs,” said Lynn Rothschild, principal investigator on the project, part of NASA’s Innovative Advanced Concepts program. “Instead, we can harness mycelia to grow these habitats ourselves when we get there.” The concept could have utility on Earth as well, as a way to solve the emissions problems associated with the construction industry, as noted above.
How does it work? The program focuses on the part of the fungus that we typically don’t see: not the stuff that ends up in a bowl of tagliatelle ai funghi but the underground networks of filaments, called mycelia, that connect and nourish mushrooms as they grow. “These tiny threads build complex structures with extreme precision,” according to NASA. And materials made from mycelia have a “higher bend strength than reinforced concrete and a higher compression strength than lumber,” the space agency points out. Scientists don’t see mycelia as only a static building material, either — they think it could be used on Mars for water filtration, humidity regulation and even bioluminescence. That’s important, because if there’s mushroom at all in these buildings, astronauts will need some light to find their way around.
What is it? Researchers at the artificial intelligence company DeepMind used AI algorithms to shed new light into the human brain, which works, as it turns out, sort of like a really good AI algorithm. In the same vein as research mined more than a century ago by Ivan Pavlov, researchers focused on the ways the brain distributes dopamine as a mode of reinforcement learning.
Why does it matter? The new research tweaks the reward prediction error theory of dopamine — an influential theory that, as the authors of a new paper in Nature note, “has explained a wealth of empirical phenomena” — and opens the door to new understandings of the brain’s dopamine system, “with potential implications for learning and motivation disorders.”
How does it work? The findings drill down on how the brain predicts what kinds of awards it’ll distribute (in the form of dopamine) in response to whatever actions we take. Neuroscientists previously understood this relationship to be more simplistic than what DeepMind researchers suspected it might be. As researcher Will Dabney told Vox, “For the last three decades our best models of reinforcement learning in AI and neuroscience have focused almost entirely on learning to predict the average future reward. But this doesn’t reflect real life — when playing the lottery, for example, people expect to either win big, or win nothing — no one is thinking about getting the average outcome.” Testing their theories in mice, researchers found support for their hypothesis that the brain “represents possible future rewards not as a single mean, but instead as a probability distribution, effectively representing multiple future outcomes simultaneously and in parallel.” That’s similar to how AI systems learn.
What is it? A team at the University of Georgia, led by chemistry professor Jin Xie, found a new weapon against cancer: nanoparticles of sodium chloride, aka salt.
Why does it matter? Sodium chloride nanoparticles, or SCNPs, are less harmful than many current treatment options and are “well-suited for localized destruction of cancer cells,” Xie said. “We expect it to find wide applications in treatment of bladder, prostate, liver, and head and neck cancer.”
How does it work? The nanoparticles act as a kind of Trojan horse: A plasma membrane typically prevents sodium from entering a cell, but it doesn’t recognize SCNPs as sodium. Once inside, according to the university publication UGA Today, “SCNPs dissolve into millions of sodium and chloride ions … and overwhelm protective mechanisms, inducing rupture of the plasma membrane and cell death. When the plasma membrane ruptures, the molecules that leak out signal the immune system that there’s tissue damage, inducing an inflammatory response that helps the body fight pathogens.” Testing the technique in mice, Xie and colleagues found that it suppressed tumor growth by 66% compared to a control group. The findings are described in Advanced Materials.
What is it? A new kind of weight-loss technique is on the horizon: Researchers at Massachusetts General Hospital are developing a “safe, injectable ice solution,” or “slurry,” that can reduce fat anywhere in the body that’s accessible via hypodermic needle.
Why does it matter? The technique builds on cryolipolysis, or “CoolSculpting,” a noninvasive treatment that uses freezing temperatures to break down fat cells under the skin. The appeal of the new technique is that it’s “easy and convenient to do,” said Harvard Medical School dermatology professor Lilit Garibyan, lead author of a new paper in Plastic and Reconstructive Surgery. “With CoolSculpting, which is a topical cooling technique, the patient has to sit there for almost an hour for enough heat to diffuse from the fat underneath the skin,” Garibyan said in a Harvard Gazette article. “With this new technique the doctor can do a simple injection that takes just less than a minute, the patient can go home, and then the fat gradually disappears.”
How does it work? Garibyan’s team developed a solution of saline and glycerol that contains roughly 20% to 40% small ice particles — similar in texture to slush. Injected directly into fat deposits, it causes cells to crystallize and die, and they’re flushed from the body within weeks. The treatment works selectively on fat and isn’t harmful to surrounding tissue, said study co-author Rox Anderson: “Even if the slurry is injected into other tissue such as muscle, there is no significant injury.”