Science Friday - Bio-Inspired Concrete, Nose Microbiome, Space News. May 29, 2020, Part 2

Episode Date: May 29, 2020

The human microbiome—our own personalized bacteria profile—plays a part in our health. The different parts of our body, from our skin to our gut, each have their own microbial profile. A team of researchers decided to explore the bacteria living inside our nose, publishing this week in the journal Cell Reports. Microbiologist Sarah Lebeer, one of the authors of the study, discusses what beneficial bacteria reside in our nose—and how this could be used to create a probiotic for upper respiratory infections. Concrete is a seemingly simple mix of wet cement, but it’s been the foundation of many civilizations. Ancient Mayans and Romans used concrete in their structures, and it is the basic building block of the sky-scraping concrete jungles we inhabit today. But it turns out, it’s still possible to improve. In an effort to create crack-free concrete that can resist the stresses of freezing temperatures, one group of researchers looked to organisms that live in sub-zero environments. Their results were published this week in the journal Cell Reports Physical Science. Engineer Wil Srubar, who is an author on that study, talks about how nature can serve as inspiration in the quest to create more sustainable concrete, wood, and other building materials. On Wednesday, a planned launch of two astronauts from Cape Canaveral had to be scrubbed due to weather. The launch would have been the first crewed flight to the space station launched from U.S. soil since 2011—and will use a Dragon rocket built by the private company SpaceX. There will be a second launch attempt this weekend. The Commercial Crew program began in 2011 to develop private launch capabilities to replace the retired space shuttle. Now, nine years later, is private industry finally ready to take over responsibilities that were once the territory of national governments? Miriam Kramer, who writes the space newsletter for Axios, and Brendan Byrne, who reports on space for public radio station WMFE in Orlando, join Ira to talk about the DEMO-2 crewed launch and other spaceflight news.       Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Ira Flato. Just a quick note before we get started. It's been a while we miss talking to you and I want you to say hello. So talk to us on the Science Friday Voxpop app on Twitter or even email us, SciFri at ScienceFriaday.com. And the Science Friday Voxpop app for this week, are you a health care worker feeling burnt out? We do want to hear from you. Maybe you're dealing with a lot of COVID patients, or seeing layoffs in your workplace. Whatever is going on, if you're a health care worker, tell us how you're feeling. That's on the Science Friday Vox Pop app wherever you get your apps. And now, what exactly lives inside of your nose? We've studied how the human microbiome, our own personalized bacteria profile, plays a part in our health, physical and mental. And we've heard a lot about the bacteria in our gut and in our skin. and now comes news of our nose.

Researchers wanted to know what lives in our noses in the hopes of creating a probiotic for upper respiratory infections. Their results were published this week in the journal Cell Reports, and that is what my next guest is here to talk about. Sarah Leiber is Professor of Bioscience Engineering at the University of Antwerp in Belgium, author of that study. Thank you, Dr. Lebeer, for joining us. You're welcome. Hello.

Tell us briefly how you did this. You swab the noses and collected the nasal microbiome of over 300 people. What did you find in there? So we had two groups of, the first group was a group of healthy volunteers. And indeed we swapped their noses and what's called the nasal pharynx. I think the nasal pharynx is now becoming very popular because, way popular because it's also used for the COVID-19 swabbing. but it's a place a little bit deeper inside your nose.

And then we had a second group where these were patients undergoing a surgery, a sinus surgery. And then they were swept during the surgery. The PhD student during the research collected samples. And what did you find? Did you find differences in people's noses? Yes. So the plan was that we were going to look for differences between the healthy subjects and a disease subject. The most interesting findings were that the healthy subjects had more healthy bacteria in their nose,

which are known as lactic acid bacteria. What is so important about the fact that they make the lactic acid? Well, lactic acid is known as a natural preservative. It's actually also what's made in yogurt and keeps your yogurt to have a longer shelf life than milk, for example. So it's able to kill the growth of unwanted bacteria. It seems to also have a communication capacity with host cells or our own human cells. Not everything is yet known on lactic acid. Is this the same kind of bacteria you would find in other parts of the body,

the same stuff that's growing in our noses? You have related bacteria in other parts of your body, especially they're quite dominant in healthy vaginas, healthy women. Normally the vagina is dominated by lactopacidus species. They're a little bit different. But that's also what we find in this article was that to adapt to the nose, the bacteria need to adapt or have some specific features because the nose is full of oxygen and has some other special features.

Since they're at the part where other germs enter our noses, are they designed to fight off infections that might be entering our noses? That's one hypothesis we have investigated in the paper. So they seem to have some evolutionary, maybe an adaptation to help us fight pathogens. For example, they have dyslectic acid, but they seem to also be able to produce other molecules that can help to reduce the growth of unwanted bacteria and even fungi.

And they also are able to communicate with certain receptors of our immune system, and they seem to have a more gatekeeping or balancing role for our reduce inflammatory reactions, for example, to other incoming particles or pathogens in the nose. It's interesting that you mentioned that because they're found in the nose, that it might be interesting to study them because of a connection, possibly to the COVID-19 infection. Yes, it's not only related to COVID-19,

but of course many viral infections, but also many allergies. They're also related to the incoming nauseous particles. our body has to react to. In fact, indeed, one of the following up questions we would like to explore is how your nasal microbiota impacts on your sustainability to COVID-19, for example. Based on my own research, I think it matters which bacteria live in your nose and how you are able to fight the virus. A lot of research, of course, still has to be done to prove this hypothesis.

It's interesting because I was reading other research this week. there was a recent study looking in mice that found that mice fed lactobacillus had improved their memory. Are you familiar with that work? Yes, I'm familiar with that work and also previous work. Of course, if I read studies with mice,

then especially memory, I think, it's very difficult to translate these findings to humans because humans are totally different and also their memory works different. But it's not so surprising that they can have an impact on memory, because especially for the gut, it's already known for decades that the bacteria in your gut can have an impact on your brain, and there's a gut-brain access.

And indeed, another follow-up study of our work is that you would like to study the impact of your nasal microbiota on brain functions, and let's see whether we get funding for such studies, but it would also play a role. Now, I know that you are, of course, one of the points of your work is looking to one day create a nasal probiotic, and you created a proof of concept probiotic in your study. Explain that to us, please. One simple idea is maybe it's possible to add beneficial bacteria to the nose of people with this chronic problems, but then, of course, you need to be able to culture this beneficial bacteria, you need to be able to formulate them in nose spray or a related device or

generate products. You need to make sure that it's safe and that the bacteria you apply in the nose. You can stick there and stay there. The nose is very efficient in clearing every particle that comes in. We did a combination of screening the best bacteria that we thought that it could stick to the nose and also the bacteria that could be dried and then put in and then later on put in a spray with saline, and then we tested, of course, the safety with ENT specialists involved in the study. Now, I know there are a lot of strains of lactobacillus. Is it a specific strain that

does its work, or does the general family of lactobacillus act in unison? Or do you really have to narrow it down to what strain we're talking about? Yeah, there's a very good question. I think in this work, we found a specific strain with specific. specific adaptations to the nose because we find it was, for example, catalase positive, so it's able to withstand oxidative stress levels. It also has specific genes that encode be called femriae, so it's their special hair-like structure so that it can stick to the nose. But the strain also has other properties such as lactic acid production and also

cell wall molecules to infect with so like deceptors. And these more conserved properties are also present in other lactobacillus. So it could well be that other lactobacillin have similar function. So in the paper that is just coming out, we find another lactobacidus. It is a lactobacidus satia, which had similar function, but it was not so good as the best strain we had. There are some conserved properties and some really specific properties. How are we finding out how the microbiome, our microbiome, communicates with the rest of the body? How does it do it?

Does they do it in many ways, many different roots? Yes, I think that's a key message. So how bacteria interact with our human body is always through multiple mechanisms of action. So it's not a single molecule interacting with one receptor in your body, living entities with a lot of molecules. And it's the sum of all these different interactions that plays a role. For example, in the case of this lactobacillite, they make this. lactic acid, which is antimicrobial, but they also have cell well molecules that interact with

immune receptors. Other molecules communicate with other more viral-related receptors or other functions. So it's very complicated to really decipher and know how all these interactions are really happening or what's happening. But it's very interesting from a microbial point of view. Tell me about why it is so difficult. what are the obstacles in creating a probiotic? First of all, you need to select a strain or a combination of bacteria that will be able to persist in the new body site. In this case, for example, for the nose,

you want bacteria that will be able to stick to the nose while for long enough time, but also don't cause inflammation, don't cause any problems. Then you need to make sure that they stay alive. that's often one of the most difficult things. Robotics are living creatures, living organisms. So you want them to stay alive, but also it needs to be in a product that it's not perishable or that you don't need to keep always in the pitch or in the freezer.

So you need to make sure that in the product they're in a kind of sleepy state. And then afterwards they become reactivated, in this case your nose. And then you need to make sure that they have the desired function so that they're active in your nose and that they have the right property. so that they reduce inflammation or they kill the bad bacteria or they promote a barrier function of your nose or other body sites where you apply. Do we have misconceptions about buying and consuming probiotics? Oh, probably, yes.

I think there might be many misconceptions. I think often, especially for the gut, it's also very difficult to really restore this bioter, really restore problems in your microbiome. I think that's very difficult with a single probiotic. And also they don't need to colonize to exert an effect. I think based on my own research, I would say most, the main function of a probiotic is not to restore your microbiome.

It's more to have immune modulatory effects and probably more subtle effect. That's interesting. So it's not that the probiotic works directly itself, but it helps to tweak up your immune system. Yes, I think it's a good summary. That's interesting. That's a great place to end, Dr. Labir. Thank you very much for taking time to be with us today.

You're welcome. Thank you. Sarah Labir is a professor of bioscience engineering at the University of Antwerp in Belgium. We'll be right back after this short break. This is Science Friday. I'm Ira Flato. On Wednesday, SpaceX and NASA were forced to postpone a scheduled launch

due to the weather. They'll try it again this weekend. And if they are successful, the astronauts on board will be the first astronauts launched from the U.S. since 2011 on board a rocket. And this is the important part. A rocket designed and built not by NASA, but by a private company, Elon Musk's SpaceX, and it's the Falcon 9 rocket. It's all part of a NASA program called Commercial Crew, developing ways powered by private industry. to get astronauts to the International Space Station again. Joining me now to talk about the launch and other space industry news are two space journalists, Miriam Kramer, who writes the space newsletter for Axios, and Brendan Byrne, who reports on space for WMFE in Orlando. Thank you both for joining us. Great to be here. Thanks for having us.

Miriam, how big a deal is this launch? Why are so many eyes on it? Like you said, it's the first launch of crew from the U.S. in nine years. It also kind of represents this new era for NASA where you have a company that's basically responsible for putting astronauts' lives in their hands and launching them to space. So it's a big moment for all involved. And it's been years in coming, hasn't it? Yeah, it has.

I mean, they were chosen for this, I think, in 2014, and they actually had years of work to develop their systems before that. So it's been a long time coming. And let's talk about why it was postponed. It was postponed just a few moments before it was to be launched, right? Yeah, just inside of 17 minutes ahead of launch. The crew was already loaded into the capsule and the rocket was being fueled, but weather just forced him to scrub the launch.

And Brendan, you were at the Kennedy Space Center on Wednesday for the launch that was scrub. What was the mood there? Were people disappointed or were there enough veterans around to know? you know we'll do it again. Well, it was definitely wet. And yes, there was quite a bit of disappointment as well. You know, you gear up for this launch and we got so close. And unfortunately, the weather wasn't with us there.

But, I mean, the mood there, it was very emotional, Ira. And maybe you can relate to this covering human launches. But this was the first human launch I covered. And there was this moment when Doug and Bob were driving two, the launch pad and they had to pass in front of the press site. And I didn't realize that this was going to happen. So I'm walking out there looking at the pad and these two drive by and Doug has his window open and he waves at us. And it was it was that moment that I realized, wow, this is a human launch. This is this is something that has never happened here in, you know, in the past

nine years. And we're returning to this, this incredible moment in U.S. space flight history. And I think for a lot of the journalists there, that was a very sobering moment that this is real, this is happening. And Miriam, let's talk about how different things are with this rocket. At first, I want to just say that I noticed that the space suits were totally different than we're used to seeing, right? And the rocket is totally different than we're used to seeing. Yeah, definitely. So I think that one of the funnier things that Elon Musk said yesterday was that he wanted the suits to be functional, but also look. And that he look cool. From the movies, they were right out of the movies. It looks very sci-fi. They're very, they're very neat looking suits. As far as the rocket goes, though, I'd say the most notable

difference about the Falcon 9 is the fact that it's reusable. The one that they were using yesterday, I believe, was a brand new rocket. But the best part about these rockets is that they can actually come back in for a landing once they've set their payload on its journey to orbit. So the first booster comes back, it's all incredibly sci-fi looking. To actually see it in person is pretty astounding, actually, to watch these like rockets come back in, break the sound beer area, and land on the ground again. So if the rocket had launched yesterday, what would have happened was about 10 minutes after launch. The first booster would have come back in for a landing on a drone ship in the Atlantic. So who owns the rocket? Does SpaceX own the rocket? Is NASA buying a sort of a car from

SpaceX like Elon Musk's Tesla or are they calling an Uber to sort of rent the rocket? So I don't know. It's kind of funny. It's somewhere in between, I think. But NASA is absolutely, you know, paying for the ride for their astronauts. It's a lot cheaper than what they have been paying for rides on Soya spacecraft, which are, it's on the order of about $80 million a seat. For the SpaceX rocket, it's around 50.

to 60 million a seat for this kind of ride. So not cheap, but also much less expensive. And it is a SpaceX rocket. This is their system. They developed it. They developed it in concert with NASA. But the idea is that they're going to be using it for tourist flights and other types of flights to orbit that aren't just having to do with NASA astronauts and with the space

station necessarily. So they have basically this whole. wide world of industry open to them now, in part because NASA helped them develop this rocket and spacecraft. Brendan, let's look ahead for the flight plan. What's the plan for the astronauts post-launch? How long will they be up there on the International Space Station? So the original plan for this mission, this mission is called demonstration mission two. It was supposed to be a test flight of the crew dragon vehicle with humans on board.

and Bob and Doug were set to go up to the space station and then, you know, come back down, you know, just a few days afterwards. That plan has changed due to scheduling on the station and the available rides that NASA has. Right now there's only a sole U.S. occupant on the station, an astronaut by the name of Chris Cassidy. And we're running out of rides from the Russian Space Agency. So Bob and Doug have trained for this to be an operational mission. So along with learning how to fly a new space vehicle of the crew dragon, the two went through kind of ISS astronaut training as well. So Bob did some EVA work to do some spacewalks.

Doug was recertified to operate the arm. If there need to be some spacewalks while they're up there, they're able to do that. So right now we're hearing that their stay will last anywhere between one in four months. So they'll be able to kind of staff up the station and give Chris a hand. So he's not the only guy working up there for NASA. Miriam, where does this launch fit in with other private spaceflight development? Are there other players who will be watching here? Or is SpaceX the only player going to the International Space Station now?

There are other players. So for the moment, it's just sort of SpaceX's game. But hot on their heels is Boeing. They also got a contract with NASA to fly crew up to the space station. They had a bit of a troubled test flight in December, which due to a series of errors basically meant that the uncrewed capsule that they had launched was not able to dock to the space station. So this year, they're going to need to refly that mission and see if they can kind of pull

it off without crew. and only then will they be able to sort of put crew onto the capsule. I think at the moment people are expecting that their first crewed flight won't be until sometime in 2021. But they are, you know, they've been doing this development just as long as SpaceX. And I think that everyone's pretty hopeful that they'll get there. It's just a little bit later than SpaceX has. And earlier this week, there was another rocket test. This one was from Virgin orbit.

Tell us about that one. Yeah. So Virgin orbit had a very exciting. first test flight for their rocket system. The unique thing about Virgin orbit is that they actually fly a plane with a small rocket mounted under the wing. And once they get up to a certain altitude, they're able to drop the rocket, the rocket ignites, and then it will bring payloads to orbit. So this was their first test flight this week. And it didn't quite go as planned. They were able to drop the rocket, the rocket ignited, but basically some error happened and it ended up,

the mission ended up failing. So the rocket kind of dropped into the ocean. But they say that they got a lot of good data from the flight and they did accomplish a fair number of their goals with it. So we'll just have to see sort of when they get back on the test launch horse and launch their next one. They're not aiming to carry human passengers, are they? They're going for satellites in orbit. Yeah, that's right. And specifically, they're going for the small satellite market, which a lot of industry folks are saying is potentially like the next big thing for the space industry or these smaller satellites that are in lower orbits. So Virgin orbit is kind of trying to capture a part of that market before other rocket companies are able to get in there first. Okay. Let's talk even further ahead. Let's talk about not staying in orbit around the Earth, but going to other planets. What is the status? Brendan, about NASA's own space launch system. Yeah, so the space launch system is basically NASA's mega rocket, right?

This is what's going to take humans to deep space. And the space launch system is a key piece of NASA's new moon shot. They're calling Artemis. Artemis was Apollo's twin sister. And the campaign will send humans to the moon. The Trump administration has charged NASA with doing this by 2024. But the space launch system has been long delay and over budget, but we are seeing it getting closer and closer to lift off.

So the core stage of this rocket. So that's the kind of, if you see pictures of it, it's the orange fuel tank and the four RS-25 rocket engines, which were used on the space shuttle. That is right now at a test facility awaiting what's called the Green Run. So they're going to try all of the brand new systems and avionics and computers. They're going to fuel it up and they're going to fire this puppy while it's still attached to a test stand just to make sure they've worked out all the kings with it. And then from there, it will come here to the Kennedy Space Center where it will launch the Orion crew capsule without a crew. This will be an uncrewed mission on a mission around the moon.

And then following that, if that's successful, there'll be a crude mission around the moon. and then finally a crude mission to the lunar surface. So the space launch system is kind of this, you know, this key piece of hardware that NASA needs to finish developing. The Orion capsule is ready to go. And then one more key piece of hardware they need is a lunar lander. And NASA has awarded contracts to three kind of design groups to develop a plan to build these landers and then eventually build these landers.

So all of these things have to come together. just right so that they can make the lunar landing in the 2020s. But space launch system is moving ahead, and that will also launch from the Kennedy Space Center, and that's going to be a big one. I cannot wait to see that when it gets here. So when it gets here is still unclear, but it's very exciting to know that that's on the horizon. And SpaceX was one of those companies that was awarded the option to design a lunar lander, was it not? That's right. Yeah, there were three three companies, and SpaceX was kind of a surprise pick to a lot of us. SpaceX's Starship was actually designed.

It's a single-stage lander, which is really cool. The three companies that were picked kind of had three different designs, which is intentional for NASA. There's this kind of redundancy built into three different systems. So SpaceX is a single stage. there was a two-stage lander and a three-stage lander. One of the organizations was a group of kind of space flight developers led by Blue Origin, which, as your listeners might know, is headed by Amazon's Jeff Bezos.

So it's very interesting to see all of these commercial players coming in competing for this human landing system, and to see three, you know, drastically different designs to the system. It gives NASA quite a few options and flexibility because this Artemis program is moving ahead at such a rapid pace. I'm Ira Flato, and this is Science Friday from WNYC Studios. So Miriam, it looks like with private launch companies coming online that NASA's role itself or other government agencies, space agencies, is going to evolve. Yeah, absolutely. And they want it to evolve. I mean, this is a moment for NASA to kind of redefine itself. And in many ways, I think it is something that's been, you know, building since the end of the shuttle program and since the Bush administration in general.

I mean, NASA wants to be a buyer of services. It doesn't want to constantly have to build its own rockets and build its own spacecraft and, you know, do everything for itself in low earth orbit because they see that industry has gotten to the point where it's mature enough that they're able to actually buy these services. from some companies. So like they're doing with SpaceX and like they want to do with Boeing, they want to open up the International Space Station to more commercial ventures and have, you know, maybe even shoot a movie with Tom Cruise on the space station. Like these are the kinds of things that they're really talking about and really considering for the first time in the agency's history. And it frees them up to maybe, you know, do those more ambitious missions that private companies are not suited for, like sending those missions to Mars. And,

building a moon base and that kind of work that maybe eventually could be taken over by industry, but for now needs to be in the purview of a government. Let's talk about moving away from the moon and heading out to Mars because there was really some interesting news this week about China preparing to carry out missions to Mars. I'm going to read a press release that says China is preparing to carry out 11 missions in two years to construct a space station. and we'll soon select the new batch of astronauts for the project. That's close to Earth.

And then is also targeting a July launch for ambitious plans for Mars missions, which will include landing a remote-controlled robot on the surface. They are not waiting for us. No, they're not. The Mars mission that's on the horizon is pretty ambitious, too. They're sending an orbiter-slash-lander in July, which is really interesting. it'll be their first interplanetary, or solo interplanetary mission. That is going to be very, very exciting to see.

It's kind of laying the groundwork for this Martian exploration campaign, right? The orbiter is going to take some really great pictures and observations from the orbit of the planet. And then the lander will explore a really interesting place on the surface and kind of prepare for a sample return mission, which is kind of the direction that the space agencies are going. going when it comes to Martian exploration. So this will definitely be one to keep an eye on launching in July. China is very ambitious with its interplanetary exploration, and this is going to be a very, very exciting mission to watch. And so what time on Saturday are they expecting to try to launch this again? Believe that's 322 in the afternoon, right, Brendan? 322 Eastern Time. That's

correct. And you'll be back there with your tuna fish sandwich, I'm sure, waiting for the lunch to have. Yeah, that was the one thing that a veteran space journalist told me was to make sure you pack a lunch. So I actually had two meals packed for the first attempt. This all looks very exciting. We will all look forward to the attempt again this weekend. I'd like to thank both of you, Miriam Kramer, who writes the space newsletter for Axios, Brendan Byrne, a space reporter for WMFE in Orlando.

So good luck to you guys this weekend. Thank you, Ira. Thanks so much. Thanks, Ira. You're welcome. We're going to take a break. And when we come back, what can the natural world teach us

about creating better building materials like concrete or transparent wood? Yeah, stay with us. We'll be right back after this break. This is Science Friday. I'm Ira Plato. If you listen to this program for a while, you know that I am a concrete nerd.

I am just fascinated with how a seemingly simple mixture of wet cement can dry and cure into durable, hard building material that has lasted for thousands of years. Think of the concrete in ancient Mayan and Roman ruins. And of course, it's a basic building block of the skyscraping concrete jungles we inhabit. So I'm always wondering,

is it possible to improve on concrete, to make it better? Well, we can always look to nature, which has a pretty good construction track record. For example, if we wanted to create crack-free concrete that resists the stresses of freezing temperatures, why not check out what organisms that live in sub-zero environments do to stay alive? That's what one group of researchers did

and published their results this week in the journal Cell Reports Physical Science. My next guest is an author on that study and also experimenting not only with modifying concrete, but creating totally new, different building materials like transparent wood. Yeah, we'll talk about it. Will Shrewbar is an assistant professor of civil environmental and architectural engineering and principal investigator of the Living Materials Lab at the University of Colorado in Boulder. Welcome to Science Friday.

Thank you very much for having me. You're a civil engineer. How did you get interested in mixing biology with engineering? So I grew up on a farm outside of Houston. And for anyone who's been on a farm, you know, things are very much alive. It's really when I started to live in cities that I came face to face with concrete every day and started to question why are buildings and cities so static and why is nature very much alive? Take Central Park in New York City, where there's a definitive line as to what is natural and what is human. And I really started to question that paradigm. So I was a structural engineer by training. And so I was always asked, questions of, you know, how can structural engineers and other building professionals contribute to sustainability? And, you know, we were using a lot of concrete, a lot of steel, a lot of glass, and materials that aren't necessarily born of the earth. I know that nature has figured out a couple of different, really cool ways to make different materials, even to survive, really

extreme conditions and extreme environments. So I thought, you know, maybe we could learn a few things from natural organisms and infuse that behavior into the materials with which we choose to build. As someone who observes a lot of concrete because I just can't help myself, one of the issues with concrete, I'm sure, as you know, and as people can tell when they walk on it, is it's subject to cracking under stress, right, from the elements. And as I said before, you looked at this in your latest study, and how did you approach this problem? So concrete, as you know, Ira, is a porous material, it's permeable, and it's really prone to what's called freeze-thaw damage. So water can permeate the surface of concrete. Water, as we know, expands when it freezes. And so that pressure,

that pressure that builds up inside, if it can't be resisted by the concrete or if that pressure has no place to go, it will pop off the surface of concrete. This particular study really challenged the conventional way by which we mitigate freeze-thaw damage in the concrete industry today. So the primary way is by putting in tiny little air bubbles into concrete mixtures. And as you can imagine, putting in tiny little air bubbles to help alleviate that pressure has some drawbacks. There are three primary drawbacks. One being that those tiny little air bubbles actually lowers the strength of the concrete. So air doesn't carry load, so it will reduce the compressive strength of concrete. Number two, tiny little air bubbles exacerbate other durability issues. So just like

kind of super highways for water and other harmful ions like chlorides to get into the concrete and cause chloride-induced corrosion, for example. And the third, you know, these air bubbles getting it exactly right, it's really, really finicky. And if you don't get it exactly right and the concrete hardens, you really have to go in and replace it, which is really, really expensive and time-consuming. Recent research has also shown that those tiny little air bubbles, even if those are fully filled with water and the concrete undergoes freeze thaw damage, it doesn't really help. So we really scratched our heads and thought,

I wonder how nature deals with freezing temperatures. And so we discovered the field of antifreeze proteins. And antifreeze proteins are produced by a myriad of fish, plants, insects, and bacteria. And these small molecules bind to the surface of a nucleated ice crystal. inside the organism and prevent it from growing and coalescing into a much larger and destructive ice crystal. The next logical step is, well, why don't we just get a bunch of this protein and put it into concrete? And we tried that, actually. For anyone who studies proteins, knows that proteins can

get really unhappy in a non-native environment. If you look at the pH of concrete, if you squeezed concrete and a drop of water came out, the pH is really high. It's about 12 and a half to 13. And proteins really don't like that. Proteins have this nice folded and chiral structure, and they like to unfold and even disintegrate at really high pH. So we thought, well, let's just find a polymer that mimics this behavior. That's exactly what we did. We found a biomimetic polymer that was a little bit more robust, a little bit more stable at high pH that also displayed this ice recrystallization inhibition activity. And we found that it did in fact resist free thaw damage in a solid ceramic, just like concrete. Where would we find a polymer like this in nature?

Yeah, so the molecule that we used was a synthetic molecule that's been used a lot in the biomedical field for making different types of plastics. Similar molecules are actually used in foods. So, for example, gelatin is an example of a molecule that has been used in some food products like ice cream to keep ice cream really, really smooth to keep those ice crystals really small. Wow. So you put jello in the concrete. We didn't quite use gelatin in this study, although my lab has an affinity for structural proteins. I understand that you've also made concrete with bacteria, cyanobacteria in it.

Living concrete? Yeah, so in a study we published a few months ago, we created really a hybrid living building material that displayed both biological and structural function. So in contrast to folks may be familiar with the concept of self-healing concrete, where researchers are putting bacteria inside of concrete that can help seal and heal cracks. In contrast to that approach, we basically used bacteria to. to help us biomineralyze and toughen a sand and hydrant gel scaffold. So there's really no cement.

And what we found is that we can keep our material alive. The bacteria actually enable the material to be produced and also to, well, was really excited about that study. We showed that we can keep the bacteria alive and enable the material itself to regenerate. We grew three generations of materials from one parent generation. And we're really just only scratching the surface with that type of concept and that type of approach to creating engineered living building materials that display biological functions. Wait, wait, I have to explore this a little bit more. So you start out with a wet cement and you put bacteria in it and as it dries, the bacteria stays alive?

In our approach, we used no cement. So we combined photosynthetic cyanobacteria, so really green cyanobacteria, with sand and a little bit of a hydrogel. And what the bacteria did is it grew, it flourished, and under the right conditions, it biominerizes, meaning it makes little tiny minerals. And those biominerales really serve as that kind of cement component. And so, it really toughened and helped bind the sand particles together. But that hydrogel kind of retained a little bit of moisture, which enabled the bacteria to thrive and survive the initial manufacturing. And we showed that the viability can be one to two times in terms of orders of magnitude higher than the traditional self-healing concrete approaches where you add bacteria directly to a concrete mixture. In those cases, really less than 1% of the initial inoculum will survive. So you come in in the morning and where you had one brick concrete block before you have two? We are often asked, will my house grow into a skyscraper?

We don't control it. But what's really great about the material system we've engineered is that by just tailoring the temperature and the humidity and really the moisture, you can control that bacterial growth. It's a lot like putting yogurt and other food in the refrigerator that really kind of shuts down bacterial metabolisms. So you can kind of control it and reawaken it when you need to, but keep it at bay if you need to as well. That's amazing. So this is sort of, as you say, self-healing concretes. Correct. It's a different, certainly a different approach to a concept of self-healing concrete. What we really challenged in the paper that we published was the concept of linear manufacturing of building materials and really harnessing the exponential growth of bacteria. So by taking one parent generation, splitting it into two and having those halves grow into two full bricks and we did that two subsequent times, we really challenged. that linear manufacturing approach where you're making one widget at a time to show that you

could theoretically manufacture building materials at an exponential scale. You've also used E. coli bacteria to produce materials. Why are bacteria so good for creating construction materials? And what would you do with those? What we're particularly excited about is blurring the boundaries between the field of synthetic biology and material manufacturing. So if you look at some of the organisms, they're really good at making materials. And in recent years, the synthetic biology or genetic programmability of certain microbes has just enabled us to toy, again, with ideas of genetically programming bacteria to make hierarchically ordered and architecturally patterned

minerals and materials with really tailored properties. So that particular study was looking at infusing an ability into E. coli bacteria to produce tiny limestone nanoparticles that had different shapes and different properties. And it was really among the first studies to be able to show that we can perhaps one day use bacteria genetically programmed them and really genetically programmed and blueprints of buildings and materials right into their DNA, which is really exciting to think about. Now, once you make the concrete, you lay the foundation, you need something to stick everything together,

and I understand you also work in bioadhesives. Correct, yeah. So, again, going back to those structural proteins, just like gelatin or even other types of polysaccharides and polypeptides, and some of them are really sticky. And really is an untapped field with understanding how even insects, you know, wasps build their nests and how insects build, you know, their colonies by sticking together dirt and sand particles with saliva and structural proteins. So, you know, we've certainly played in the lab with some bioadhesives from structural processes. proteins and have shown that they rival the best engineered wood adhesives on the market today.

I also understand that you make transparent wood. Transparent wood, really? We can make wood transparent, absolutely. So the process is actually quite simple. If you take balsa wood that you get at your local hardware store or any kind of wood veneer, what you can do through a simple chemical process is remove all of the brown lignin from the wood. It's a lot like paper making where you can remove the brown lignin through an oxidation process. And what you end up with is a really nice white scaffold that is certainly not transparent, but it does look like a piece of 3D paper almost. And if you infill the porous structure of that wood with a polymer, resin, that has a refractive index that matches that of cellulose, which is about 1.5, what you get is a

material with which that has the ability for light to pass through. So we're really excited about that because you can start to imagine applications such as light fixtures inside of buildings or even parts of windows, sunshades, things of that nature that would lend themselves well to something that's a little bit more bio-based, biorenewable, that has the great properties of glass and other translucent to transparent materials, but has a much lower manufacturing energy than making glass from melting sand. I'm Ira Plato, and this is Science Friday from WNYC Studios. Of course, the $64 question is, how do you get the building industry to adopt any or all of these new

materials. You know, as we know, the building industry is extremely conservative, and rightfully so, right? We have to hold paramount the safety, health, and well-being of the public. You know, you trust your lives every day to architects and engineers that have done the right calculations to keep people safe. So anytime a new product is introduced into the market, there certainly is some criticism and some skepticism. And I applaud that. You know, what we really need is a little bit of help from from policymakers to help put, for example, caps on embodied carbon on our building materials to help infuse more biological and bio-based materials into the built environment. And we also need really motivated and dedicated clients and owners, building owners and developers to stand up in terms. say, you know, these are certainly materials that I want to explore, and I want to be a test bed

for different materials that I'd like to see in the building industry. Well, we've unfortunately run out of time. I want to thank you for taking time to be with us today. Thank you so much. It's really been a pleasure. Will Schrooper is an assistant professor of civil, environmental and architectural engineering principal investigator of the Living Materials Lab at the University of Colorado in Boulder. And we have photos of this bio-inspired concrete and transparent wood up on our website at Science Friday.com. And we have an interview up there with artist Annie Lou. Early on, an authority figure told me that girls are bad at math, and it really sunk in.

It wasn't until I decided to really pursue art that I was like, oh, I'm not that bad at circuit making. Like, this isn't actually outside my realm of possibility. You can read and see pictures of Anilu's visceral feminist biotech-infused works at Science Friday.com slash biology art. Have a great weekend. I'm Ira Flato.