AI transcript
0:00:17 Today’s show has some classic plain vanilla innovation, as people playing with lasers and
0:00:22 trying to make new kinds of materials, people trying to improve vaccine delivery, people
0:00:24 trying to reduce food waste.
0:00:29 But today’s show also has some kinds of innovation that we don’t hear so much about.
0:00:33 Like thousands of years of selective breeding of caterpillars.
0:00:41 Also, millions of years of caterpillar evolution that have created this amazing, super thin,
0:00:47 super strong fiber that the caterpillar spins into a cocoon, basically by doing 3D printing.
0:00:51 Which, does it even count as innovation if a caterpillar does it?
0:00:53 I’m going to go with yes.
0:00:58 For the purposes of this show, of this moment, I’m going to say yes.
0:01:06 I’m Jacob Goldstein, and this is What’s Your Problem?
0:01:09 The show where I talk to people who are trying to make technological progress.
0:01:12 My guest today is Fiorenzo Omineto.
0:01:17 He’s a professor of biomedical engineering at Tufts University, and he studies silk.
0:01:19 Fiorenzo’s problem is this.
0:01:25 How do you turn a fabric people have been using for thousands of years into useful, cutting-edge materials?
0:01:32 Fiorenzo’s background is in physics and optics, but he runs what’s known as the Silk Lab.
0:01:39 He and his colleagues take natural silk, isolate the key protein, and use it to create new, useful stuff.
0:01:47 Fiorenzo got into silk one day about 20 years ago, when he ran into his colleague David Kaplan in the hall at work.
0:01:53 David handed him something that looked like a little piece of plastic, but that turned out, of course, to be silk.
0:01:58 So David is responsible for me, for me working with silk.
0:02:03 So my background is really technical, and I come from material science, laser physics.
0:02:10 And with this background, I joined a biomedical engineering department, which is already sort of like a leap of faith, if you will.
0:02:12 You’re kind of a weirdo there?
0:02:14 Yeah, I suppose.
0:02:16 I suppose.
0:02:17 Let’s just say orthogonal.
0:02:21 Yes, that’s a high-brow way of saying weirdo.
0:02:23 I’ve been orthogonal in a lot of settings.
0:02:25 I suppose, right?
0:02:26 Orthogonal two.
0:02:27 Orthogonal two, a lot of settings.
0:02:28 Sorry.
0:02:29 Yes, orthogonal two.
0:02:30 Yes.
0:02:34 And we had a conversation in the hall.
0:02:46 David’s a tissue engineer, and then the premise of tissue engineering is finding biocompatible materials that can enter the body and can serve as scaffolding for cells to rebuild our tissues.
0:02:56 So we’re in the hallway, and he presents me with this little piece of plastic that was supposed to be a tissue engineering scaffold for a replacement cornea.
0:02:56 Okay.
0:03:08 But the cells weren’t able to grow inside of it, and so he said, can you maybe use your lasers to poke some holes in it so that the cells can grow in, and then if they permeate this, then they can regrow the cornea.
0:03:14 So I took this piece of plastic, I took it to the lab, and I put a laser beam on it, and I lost the laser beam.
0:03:18 When I put the laser beam on this little piece of plastic, I couldn’t see the spot.
0:03:24 And to an optics geek like me, that means that the surface is incredibly smooth.
0:03:30 It means that there’s no scattering, and this surface is very beautiful from an optical perspective.
0:03:36 When you say you lost it, you mean it just kind of disappeared on there, like you didn’t see a little red dot or whatever?
0:03:37 Is that what that means?
0:03:39 That is exactly what it means.
0:03:45 And generally, you see the red dot when you have some roughness that gives you the scattering and makes the spot visible.
0:03:53 And so that one question led to the other, and we started doing optics with it, and we started doing these holograms and materials out of what turned out to be silk.
0:03:56 Right. What are your first ideas?
0:04:00 So you realize, oh, this is silk, and weirdly, it has this property of being crazy smooth.
0:04:05 What do you think about doing with it once you realize that?
0:04:16 You basically have a construction material that starts from water and a protein that floats around, and then you can turn it into multiple forms, so films, sponges, blocks, what have you.
0:04:22 You can print it, you can print it, you can spray it, you can 3D print it, paint it, et cetera.
0:04:39 And all of this is in a format that is edible, implantable, and that as we discovered, as we went along, that also stabilizes biological activity, you know, acts as a preservative for molecules that otherwise need to be refrigerated.
0:04:40 Oh, interesting.
0:04:42 So this is where things diverged.
0:04:56 And there are a lot of sort of basically biological applications, medical and sort of medical adjacent applications, because this benign, naturally occurring protein that is the essence of silk has these wonderful properties.
0:05:10 That’s right. That’s right. And so we started doing, we started doing things for fun. I mean, we started looking at the optical properties, we started doing optical devices, and we started doing imprinting, and we looked at where were the limits of fabrication that we could push.
0:05:14 How much cool and useful stuff could you make with silk, basically?
0:05:22 That’s right. And there’s also, you know, the wow factor, because, you know, it’s a very different format than having silk that looks like this.
0:05:24 Yes. Now you’re holding up a silk scarf.
0:05:26 Now I’m holding up a silk scarf, yes.
0:05:48 So let’s, I want to get to a lot of the applications that have come out of your work. But before we do that, I just want to talk about silk for a few minutes, because it’s interesting, and it’s sort of the core of why you’ve been working on this for almost 20 years, right? So, like, why is silk so amazing?
0:05:55 I wish I had, like, a one-liner answer to this.
0:05:58 Yeah, a one-liner. Let’s talk about it. Let’s just talk about silk. Tell me about silk.
0:06:05 So silk, particularly, textile silk, is one of the most engineered natural materials that there is.
0:06:15 Legend has it, you know, it wasn’t quite the apple that fell from the tree, but it was the cocoon that fell from the tree while a princess was drinking tea.
0:06:15 Yes.
0:06:18 And then this lustrous fiber came off.
0:06:27 This is in China more than a thousand years ago. I mean, we know there’s the myth, but we know that they’ve been making silk in China for more than a thousand years, certainly, right?
0:06:34 But most importantly, I think that the thing that is unappreciated is that the Bombex Mori caterpillar has been domesticated for all of this time.
0:06:42 With all of the intrigue of the, you know, my line of silkworms produces a very fine silk.
0:06:45 This other line of silkworms doesn’t do as well.
0:06:49 And so the finest products that you can get, you get from a certain farm.
0:06:52 This was all the intrigue of optimizing.
0:06:55 Right. I mean, it’s innovation, right?
0:06:58 There are literally centuries of innovation.
0:07:04 And just to say it for, I think most people know, but like there is a particular worm, right?
0:07:09 The silkworm is whatever, the larval form of a particular moth, right?
0:07:10 If I’m getting that right.
0:07:18 And it spins its cocoon out of this material that is basically silk, or was what they used to make silk, right?
0:07:22 And it only eats the mulberry tree bark or something, right?
0:07:24 Or it prefers the mulberry tree bark?
0:07:28 A majestically picky eater, yes.
0:07:30 And it’s remarkable.
0:07:38 And as I mean, as I understand it, the optimization, it’s actually they have, through, you know, breeding basically over time,
0:07:46 have made it so that the moths make more silkworms, you get more silkworms, you get more silk, you know, more quickly, right?
0:07:50 So it already comes to us as this incredibly optimized thing.
0:07:55 There’s nature, it’s done a tremendous amount of work, and then people in China for a thousand years have done more, right?
0:07:57 That’s right.
0:07:58 And then it propagated all over the place.
0:08:00 And it’s really very technical.
0:08:09 And so this agricultural crop that gives textiles that are very prized for their luster, for their look, for their thermal properties, for their durability.
0:08:10 Right.
0:08:12 Like great long underwear, right?
0:08:14 High-end boxers, nice scarf.
0:08:16 Absolutely.
0:08:18 There’s like all sorts of beautiful things.
0:08:20 But they come in this format.
0:08:22 I mean, and I’m holding up a cocoon right now.
0:08:23 They come in this format.
0:08:26 Is that a real cocoon or is that like a model?
0:08:27 No, no, no.
0:08:28 This is a real cocoon.
0:08:29 Here, wait.
0:08:30 Hold it up again.
0:08:32 So it’s, let’s talk about it.
0:08:34 Let me find, here we go.
0:08:35 Let me find one that is.
0:08:37 How many cocoons do you have on your desk?
0:08:39 You just put one down and picked up another one.
0:08:42 We have, we are full of cocoons.
0:08:43 So I’m holding it.
0:08:43 Okay.
0:08:45 Tell me about it.
0:08:45 It’s white.
0:08:47 It’s white, white, white, right?
0:08:49 It’s snow white, it looks on the picture.
0:08:56 So it’s a snow white, giant, giant, yep, a giant bean.
0:08:58 Yeah, it’s bigger than a bean.
0:08:59 I’m trying to think, what is that size?
0:09:04 Like if you smushed a ping pong ball into an oblong shape, would it be about that size?
0:09:05 Yeah, about that size.
0:09:07 And you’re holding it by a thread.
0:09:09 Is that a little silken thread that you’re holding it by?
0:09:10 I can’t even see it.
0:09:11 It’s invisible to me.
0:09:13 Yeah, I’m trying to figure out.
0:09:15 There, you can kind of see it now, maybe.
0:09:17 I mean, it’s cool that it’s invisible.
0:09:19 It’s magic.
0:09:21 It’s like a spider web, right?
0:09:26 In fact, spider webs are quite similar, but it’s hard to breed spiders, right?
0:09:27 That’s what I read.
0:09:31 So spiders cannot be domesticated, but caterpillars can.
0:09:33 There are billions of these cocoons.
0:09:34 Yeah.
0:09:37 There are a lot, a lot, a lot of these cocoons.
0:09:42 But the remarkable thing is that each cocoon is an engineering wonder, because if you take
0:09:46 the cocoon and you unwind it, so you wash the glue away that the worms use to keep it
0:09:52 together, or the caterpillars use to keep this together, and you pull, you have almost one
0:09:53 kilometer of uninterrupted thread.
0:09:58 So 10 micron thread that is composed by two silk fibers that are held together.
0:10:01 The 10 microns means about a tenth of the diameter of your hair.
0:10:07 Each fiber is composed by two individual fibers that are held together by that glue that I mentioned
0:10:11 before, because there are two spinning glands in the caterpillar.
0:10:16 And then all held together in this non-woven format that is extremely resilient.
0:10:19 It’s something that you just can’t tear.
0:10:22 And think, there’s no weave in here.
0:10:26 It’s just a worm that is building up layer by layer by layer as it’s building this cocoon.
0:10:28 It’s like additive manufacturing.
0:10:29 It’s like 3D printing.
0:10:30 Yeah.
0:10:31 It is absolutely that.
0:10:33 This is a biological 3D printer.
0:10:38 It’s a filamentary 3D printer that builds a cocoon from the inside, too.
0:10:42 Yeah, the caterpillars on the inside doing it.
0:10:48 So, okay, so there is this incredible natural context to begin with, this incredible thing
0:10:49 that the silkworm does.
0:10:55 And then on top of that, we have the kind of innovation and optimization of whatever, a thousand
0:11:00 plus years of farming and, you know, commercial evolution.
0:11:06 And then you kind of walk onto the stage and you realize, oh, this stuff is really cool.
0:11:09 And you start playing with it.
0:11:14 And let’s talk about some of the things that have come out of it, right?
0:11:16 It’s not purely academic work.
0:11:17 There have been commercial spinoffs.
0:11:25 So the important qualities of the material fabrication process that open up an endless kit of material
0:11:31 wonder are the fact the end formats of material you can eat, you can implant in the body, you
0:11:37 can mix things into this glass of water and silk, mix things that are delicate biologically,
0:11:42 and you can preserve them, and then you can control the degradation of the materials.
0:11:47 You can dip them in water and they dissolve immediately, or you can dip them in water and
0:11:48 they’ll stay put for years.
0:11:51 Just depending on how you build it, essentially.
0:11:53 How you put the proteins together.
0:11:59 It’s just imagine a bunch of little Lego pieces that are floating around, and depending on how
0:12:04 hard you press it, the material lasts more or less, and you can control the sizes of the
0:12:06 bricks that you put in the solution and how they’re pressed together.
0:12:12 And so to a material scientist, having these functional aspects in a material just is mind
0:12:18 blowing, because you can start really imagining what, if you look at all of the materials that
0:12:23 surround you and you start saying, well, what if I could plant this in my garden?
0:12:24 What if I could eat it?
0:12:26 What if I could put biological communicators inside it?
0:12:28 What if I could put chemistries inside here?
0:12:33 That are very difficult to put in by other means.
0:12:36 So then this just opens up a world of craziness.
0:12:40 Of delightful craziness, right?
0:12:41 Good craziness.
0:12:48 I think the thing that I still find myself very surprised by is that after now nearly 20
0:12:54 years of working with this material, I think I’m still as excited about the potential of this
0:12:56 material as I was on day one.
0:13:05 Still to come on the show, using silk to find a better way to deliver vaccines, and also
0:13:07 using silk to help preserve fruits and vegetables.
0:13:10 Also, more things to do with silk.
0:13:22 What’s something that is in the world based on your work?
0:13:28 One of the companies that is called Vaxxas is now using silk-based technology to do microneedle
0:13:31 patches with therapy that doesn’t need to be refrigerated.
0:13:37 So imagine just putting on a Band-Aid rather than going to a place to get an injection and
0:13:41 not having to worry about storing your therapy in the fridge.
0:13:43 Particularly important in the developing world, right?
0:13:45 We take the cold chain for granted here.
0:13:47 And yes, it’s a hassle to go to the pharmacy and get a shot.
0:13:52 But like, there are parts of the world where like, you know, the vaccine has to be called
0:13:55 from the time it’s made until it goes into your arm, essentially.
0:13:55 Yes.
0:13:58 So it has to be in a truck and a ship and everywhere.
0:14:00 It has to stay cold and you have to have reliable power.
0:14:03 And there are big parts of the world where that just doesn’t exist, right?
0:14:06 So it actually is a real problem on a global scale.
0:14:10 I would argue also that it potentially could become even more profitable.
0:14:15 I believe that there’s a lot of opportunities still out there for these classes of material
0:14:17 to be, to generate an incredible amount of revenue.
0:14:20 I mean, do you mean just because it’s cheaper?
0:14:22 Because if you don’t have to keep it cold, it’s more efficient?
0:14:26 Or like, what makes you think of, or just because people prefer, what makes, like, I’m interested.
0:14:29 I just, what makes you think of that here in the conversation?
0:14:35 I think that the functional surprise is what makes this an appealing product and it makes
0:14:36 it economically viable.
0:14:42 I think that having, that trying to substitute materials one for one is very difficult given
0:14:44 the sophistication of what we have today.
0:14:49 But I think that if your material manages to do something unexpected, it brings more value
0:14:50 to a person.
0:14:52 So you’re saying it’s not just not the cold chain.
0:14:53 It’s, you don’t have to get a shot.
0:14:55 You just put this sticker on your arm.
0:14:57 It’s a collection of things.
0:14:59 And so the jury is out of whether this is true or not.
0:15:05 I think the opportunity is big, but I see also that it requires an enormous amount of dedication
0:15:06 and it requires entrepreneurship.
0:15:11 And that side of it is clearly not your side, it seems, as you’re talking about it.
0:15:13 Well, it can’t be.
0:15:15 There are professors who also start companies.
0:15:16 Yes.
0:15:21 But I think that I’m a big believer in the fact that you have to dedicate your full attention
0:15:23 to something to bring it at its maximum level.
0:15:31 So there’s another thing that people are developing based on your work and your colleagues’ work
0:15:35 for vocal cords, right?
0:15:38 They call it vocal folds, but it’s basically vocal cords.
0:15:39 Tell me about that.
0:15:45 So for example, one of the examples is that in certain cases, when you lose mechanical properties
0:15:51 in your vocal fold, your vocal cords are not able to vibrate anymore and you lose your capacity
0:15:52 to speak.
0:15:58 And so one of the strategies would be to restore the strength of the vocal fold so that you give
0:16:00 mechanical fortitude to that.
0:16:06 So we studied this formulation where imagine that you have a dense injectable jello that comes
0:16:13 and stays and stays put in some place and mixes with your native tissue and makes it more for…
0:16:13 I see.
0:16:14 Okay.
0:16:20 So one of the companies that took the gel technology out studied this and they came up with an injectable
0:16:26 format that restores the mechanical properties of the fold and actually gives the capacity of the
0:16:27 patients to speak again.
0:16:29 This is an FDA-approved therapy.
0:16:30 So it worked.
0:16:32 So it worked.
0:16:34 So this is something that you can get today.
0:16:37 Food preservation.
0:16:42 Somebody’s working on using some silk-based technology to make fresh food stay good longer.
0:16:43 Tell me about that.
0:16:48 So it turns out that the silk liquid is very good at coating objects.
0:16:54 And if you take, for example, a strawberry and you dip it in water and silk, silk coats the
0:16:58 strawberry with a thin layer of material that acts as a fruit preservative.
0:17:04 And it’s very effective to prolong the shelf life at room temperature of materials by a week
0:17:05 or a couple of weeks.
0:17:08 And then I guess it depends on what you use it on.
0:17:10 And every food has its own story.
0:17:15 At the time, we, in the lab, we tried it on bananas and on strawberries.
0:17:21 And we saw that at room temperature, we could keep bananas and strawberries fresh for an extra
0:17:23 week, 10 days or something like that.
0:17:29 And so where is that sort of product in the arc of commercialization, this silk-based fruit,
0:17:31 you know, preservative?
0:17:35 Honestly, I think that this is a question for the company itself.
0:17:40 But I know that some product has been successfully applied to leafy greens.
0:17:45 And I think that the use case there is the ability to enhance logistics.
0:17:49 Give you more time to get the greens from the farm to the table.
0:17:50 Exactly.
0:17:54 From point A to point B and without refrigeration, which is a big deal.
0:17:54 Okay.
0:17:56 Tell me what you’re working on now.
0:17:58 What are we working on now?
0:18:00 We’re working on sensing a lot.
0:18:05 We have friends that design proteins that are very, very sensitive and very, very specific.
0:18:12 So there are possibilities of giving formats to say things, for example, that detect hormones.
0:18:18 So one of the things that we did recently was to make an ink with a design or a protein, if
0:18:23 you will, that was very sensitive and very specific to human estrogen receptor too, which is one
0:18:26 of the hormones that is responsible for breast cancer.
0:18:32 So you start imagining things like painting and the inside of a bra.
0:18:38 So you have a monitor of recurrence, for example, or you have a monitor for breast cancer.
0:18:42 We did the same thing with toxins like botulin and hepatitis B.
0:18:48 And so all of these things become very powerful when you have them in these different formats
0:18:49 that are very unexpected.
0:18:59 So the core thing you have ultimately with the silk is this benign stabilizing force, right?
0:19:02 That’s the thing you’re applying in all these different detection settings.
0:19:02 Is that right?
0:19:12 A way to take whatever essentially detectors, these protein detectors that might, whatever,
0:19:14 decompose in other settings.
0:19:17 You’re stabilizing them in a very kind of safe, benign way.
0:19:21 That seems like the core thing that is happening in all these different use cases you’re describing.
0:19:21 Is that right?
0:19:23 That is true.
0:19:27 But the other thing that is very important is that you stabilize these, and that’s the
0:19:28 functional part.
0:19:29 But then you shape it.
0:19:31 And the shapes are very, very technological.
0:19:36 So the other thing that we’re working on that is very exciting is how to control silk on the
0:19:39 nanoscale and actually have these things very precisely localized.
0:19:44 And that can lead to really nice interfaces with, for example, with semiconductors.
0:19:47 Say a little more about that one.
0:19:53 So we had a recent paper where we showed that in a transistor, we can put a thin layer of silk
0:19:59 within the transistor, and we can use the state of silk to change the way that the transistor
0:20:00 switches.
0:20:01 Huh.
0:20:04 Switches, which is the fundamental thing a transistor does.
0:20:06 Goes from on to off, basically.
0:20:07 That’s right.
0:20:13 So if you could imagine this multiplied by a trillion transistors, it would be a very
0:20:18 powerful way to sense things, for example, or to analyze things.
0:20:18 Yeah.
0:20:20 Why not?
0:20:28 So just to land the main part of the conversation here, you’ve been working with silk for almost
0:20:29 20 years.
0:20:35 Like, if you sort of zoom out and look at the big picture arc of your work, what do you come
0:20:36 away with?
0:20:39 There are two main things, I think.
0:20:43 One is a thing that comes from wonder and surprise.
0:20:50 And I think that the more you look at things around you and you interpret and you are amazed
0:20:55 by the things around you, the more you learn about them, the more inspired you are, I would
0:20:56 say.
0:21:02 And then the other thing that I would say is that natural systems, natural materials have
0:21:08 an unbelievable degree of hierarchical sophistication.
0:21:16 And by that, I mean, they are so exquisitely engineered at all scales to provide very simultaneous
0:21:19 functions that are technologically incredibly relevant.
0:21:24 You know, so like the way that they manage energy, the way that they repel infection, the way
0:21:31 that they are super hydrophobic, the way that they’re resilient by being ultra light, their
0:21:35 ability to keep warm and to keep cold, depending on the need.
0:21:39 It’s just, it’s just an endless, the way that they self heal.
0:21:42 It’s like an endless stream of things that is incredible.
0:21:48 Nature has a lot of ideas to do really smart things, to do really meaningful things, to do
0:21:50 profound things and to do very profitable things.
0:21:56 We’ll be back in a minute with the lightning round.
0:22:06 Let’s finish with the lightning round.
0:22:11 What’s one thing about lasers that you wish more people understood?
0:22:14 How profoundly different they are from a light bulb.
0:22:15 Huh.
0:22:18 Say a little more.
0:22:20 I feel like I should know that better.
0:22:20 Tell me.
0:22:24 Lasers are light, and we kind of take for granted that this light travel
0:22:29 travels in a line and gives you a spot, and they’re the same, it’s the same light that
0:22:31 you get from a light bulb, except that the light from the light bulb goes all over the
0:22:33 place, whereas the laser is directional.
0:22:38 And that fact that the laser is directional is amazing material magic.
0:22:39 Uh-huh.
0:22:40 Why?
0:22:44 It gives it order.
0:22:47 So it’s very, very ordered light.
0:22:53 You take something that is chaotic and you make it keep step with time and with space.
0:22:53 Wow.
0:22:58 And it’s very important because it’s at the basis of a lot of things, including self-driving
0:23:02 cars that don’t smash the two into one another, for example, in some cases.
0:23:06 What’s your favorite use of a laser in fiction, in a movie, in a book?
0:23:11 Oh, obviously laser beams on sharks.
0:23:12 Austin Power.
0:23:14 It’s, I mean, it’s Dr. Evil’s.
0:23:15 It’s Dr. Evil.
0:23:16 Good.
0:23:22 Um, so as I understand it, you were an Oppenheimer fellow at Los Alamos.
0:23:23 I was.
0:23:25 What’d you think of the movie Oppenheimer?
0:23:26 Oh, gosh.
0:23:29 Uh, uh, how much time do we have?
0:23:30 This is not a lightning question.
0:23:35 Um, yeah, it was, uh, it was, if I liked it, it’s complicated.
0:23:40 When you were at Los Alamos 20 years ago, were like the, the, you get, you catch any Manhattan
0:23:42 Project vibes or was it just kind of a relic?
0:23:48 Uh, no, I, I think that it’s very present that the history is palpable in, in the lab.
0:23:53 And I think that one of, one of the best things is to go to the museum and see their guest books
0:23:58 and see, and see what people write on the guest book after they’ve gone through the whole story
0:23:59 of the Manhattan Project.
0:24:03 And it’s very, the range of comments is astounding.
0:24:10 It’s from, you know, international atomic agency officers to senators, to a high school football
0:24:16 team, to Japanese visitors, you know, and, and it was at least very much in the culture
0:24:17 of the lab.
0:24:20 And I think that there’s a, I can’t see how, how it wouldn’t be.
0:24:21 Yeah.
0:24:24 True that you wrote a Vespa?
0:24:25 True.
0:24:27 You still write a Vespa?
0:24:29 Not often.
0:24:29 I do.
0:24:32 I own one, but it’s gathering a lot of dust.
0:24:35 You think Vespas are overrated or underrated?
0:24:40 Oh, that’s a, that’s, I’m not gonna, I’m not gonna, I’m not gonna even comment on that.
0:24:42 I think they, I think, I think they look great.
0:24:52 Lorenzo Omenero runs the Silk Lab at Tufts University.
0:24:56 Today’s show was produced by Gabriel Hunter Chang.
0:25:01 It was edited by Lydia Jean Cott and engineered by Sarah Bruguer.
0:25:04 You can email us at problem at Pushkin.fm.
0:25:09 I’m Jacob Goldstein, and we’ll be back next week with another episode of What’s Your Problem?
0:25:09 What’s Your Problem?
0:00:22 trying to make new kinds of materials, people trying to improve vaccine delivery, people
0:00:24 trying to reduce food waste.
0:00:29 But today’s show also has some kinds of innovation that we don’t hear so much about.
0:00:33 Like thousands of years of selective breeding of caterpillars.
0:00:41 Also, millions of years of caterpillar evolution that have created this amazing, super thin,
0:00:47 super strong fiber that the caterpillar spins into a cocoon, basically by doing 3D printing.
0:00:51 Which, does it even count as innovation if a caterpillar does it?
0:00:53 I’m going to go with yes.
0:00:58 For the purposes of this show, of this moment, I’m going to say yes.
0:01:06 I’m Jacob Goldstein, and this is What’s Your Problem?
0:01:09 The show where I talk to people who are trying to make technological progress.
0:01:12 My guest today is Fiorenzo Omineto.
0:01:17 He’s a professor of biomedical engineering at Tufts University, and he studies silk.
0:01:19 Fiorenzo’s problem is this.
0:01:25 How do you turn a fabric people have been using for thousands of years into useful, cutting-edge materials?
0:01:32 Fiorenzo’s background is in physics and optics, but he runs what’s known as the Silk Lab.
0:01:39 He and his colleagues take natural silk, isolate the key protein, and use it to create new, useful stuff.
0:01:47 Fiorenzo got into silk one day about 20 years ago, when he ran into his colleague David Kaplan in the hall at work.
0:01:53 David handed him something that looked like a little piece of plastic, but that turned out, of course, to be silk.
0:01:58 So David is responsible for me, for me working with silk.
0:02:03 So my background is really technical, and I come from material science, laser physics.
0:02:10 And with this background, I joined a biomedical engineering department, which is already sort of like a leap of faith, if you will.
0:02:12 You’re kind of a weirdo there?
0:02:14 Yeah, I suppose.
0:02:16 I suppose.
0:02:17 Let’s just say orthogonal.
0:02:21 Yes, that’s a high-brow way of saying weirdo.
0:02:23 I’ve been orthogonal in a lot of settings.
0:02:25 I suppose, right?
0:02:26 Orthogonal two.
0:02:27 Orthogonal two, a lot of settings.
0:02:28 Sorry.
0:02:29 Yes, orthogonal two.
0:02:30 Yes.
0:02:34 And we had a conversation in the hall.
0:02:46 David’s a tissue engineer, and then the premise of tissue engineering is finding biocompatible materials that can enter the body and can serve as scaffolding for cells to rebuild our tissues.
0:02:56 So we’re in the hallway, and he presents me with this little piece of plastic that was supposed to be a tissue engineering scaffold for a replacement cornea.
0:02:56 Okay.
0:03:08 But the cells weren’t able to grow inside of it, and so he said, can you maybe use your lasers to poke some holes in it so that the cells can grow in, and then if they permeate this, then they can regrow the cornea.
0:03:14 So I took this piece of plastic, I took it to the lab, and I put a laser beam on it, and I lost the laser beam.
0:03:18 When I put the laser beam on this little piece of plastic, I couldn’t see the spot.
0:03:24 And to an optics geek like me, that means that the surface is incredibly smooth.
0:03:30 It means that there’s no scattering, and this surface is very beautiful from an optical perspective.
0:03:36 When you say you lost it, you mean it just kind of disappeared on there, like you didn’t see a little red dot or whatever?
0:03:37 Is that what that means?
0:03:39 That is exactly what it means.
0:03:45 And generally, you see the red dot when you have some roughness that gives you the scattering and makes the spot visible.
0:03:53 And so that one question led to the other, and we started doing optics with it, and we started doing these holograms and materials out of what turned out to be silk.
0:03:56 Right. What are your first ideas?
0:04:00 So you realize, oh, this is silk, and weirdly, it has this property of being crazy smooth.
0:04:05 What do you think about doing with it once you realize that?
0:04:16 You basically have a construction material that starts from water and a protein that floats around, and then you can turn it into multiple forms, so films, sponges, blocks, what have you.
0:04:22 You can print it, you can print it, you can spray it, you can 3D print it, paint it, et cetera.
0:04:39 And all of this is in a format that is edible, implantable, and that as we discovered, as we went along, that also stabilizes biological activity, you know, acts as a preservative for molecules that otherwise need to be refrigerated.
0:04:40 Oh, interesting.
0:04:42 So this is where things diverged.
0:04:56 And there are a lot of sort of basically biological applications, medical and sort of medical adjacent applications, because this benign, naturally occurring protein that is the essence of silk has these wonderful properties.
0:05:10 That’s right. That’s right. And so we started doing, we started doing things for fun. I mean, we started looking at the optical properties, we started doing optical devices, and we started doing imprinting, and we looked at where were the limits of fabrication that we could push.
0:05:14 How much cool and useful stuff could you make with silk, basically?
0:05:22 That’s right. And there’s also, you know, the wow factor, because, you know, it’s a very different format than having silk that looks like this.
0:05:24 Yes. Now you’re holding up a silk scarf.
0:05:26 Now I’m holding up a silk scarf, yes.
0:05:48 So let’s, I want to get to a lot of the applications that have come out of your work. But before we do that, I just want to talk about silk for a few minutes, because it’s interesting, and it’s sort of the core of why you’ve been working on this for almost 20 years, right? So, like, why is silk so amazing?
0:05:55 I wish I had, like, a one-liner answer to this.
0:05:58 Yeah, a one-liner. Let’s talk about it. Let’s just talk about silk. Tell me about silk.
0:06:05 So silk, particularly, textile silk, is one of the most engineered natural materials that there is.
0:06:15 Legend has it, you know, it wasn’t quite the apple that fell from the tree, but it was the cocoon that fell from the tree while a princess was drinking tea.
0:06:15 Yes.
0:06:18 And then this lustrous fiber came off.
0:06:27 This is in China more than a thousand years ago. I mean, we know there’s the myth, but we know that they’ve been making silk in China for more than a thousand years, certainly, right?
0:06:34 But most importantly, I think that the thing that is unappreciated is that the Bombex Mori caterpillar has been domesticated for all of this time.
0:06:42 With all of the intrigue of the, you know, my line of silkworms produces a very fine silk.
0:06:45 This other line of silkworms doesn’t do as well.
0:06:49 And so the finest products that you can get, you get from a certain farm.
0:06:52 This was all the intrigue of optimizing.
0:06:55 Right. I mean, it’s innovation, right?
0:06:58 There are literally centuries of innovation.
0:07:04 And just to say it for, I think most people know, but like there is a particular worm, right?
0:07:09 The silkworm is whatever, the larval form of a particular moth, right?
0:07:10 If I’m getting that right.
0:07:18 And it spins its cocoon out of this material that is basically silk, or was what they used to make silk, right?
0:07:22 And it only eats the mulberry tree bark or something, right?
0:07:24 Or it prefers the mulberry tree bark?
0:07:28 A majestically picky eater, yes.
0:07:30 And it’s remarkable.
0:07:38 And as I mean, as I understand it, the optimization, it’s actually they have, through, you know, breeding basically over time,
0:07:46 have made it so that the moths make more silkworms, you get more silkworms, you get more silk, you know, more quickly, right?
0:07:50 So it already comes to us as this incredibly optimized thing.
0:07:55 There’s nature, it’s done a tremendous amount of work, and then people in China for a thousand years have done more, right?
0:07:57 That’s right.
0:07:58 And then it propagated all over the place.
0:08:00 And it’s really very technical.
0:08:09 And so this agricultural crop that gives textiles that are very prized for their luster, for their look, for their thermal properties, for their durability.
0:08:10 Right.
0:08:12 Like great long underwear, right?
0:08:14 High-end boxers, nice scarf.
0:08:16 Absolutely.
0:08:18 There’s like all sorts of beautiful things.
0:08:20 But they come in this format.
0:08:22 I mean, and I’m holding up a cocoon right now.
0:08:23 They come in this format.
0:08:26 Is that a real cocoon or is that like a model?
0:08:27 No, no, no.
0:08:28 This is a real cocoon.
0:08:29 Here, wait.
0:08:30 Hold it up again.
0:08:32 So it’s, let’s talk about it.
0:08:34 Let me find, here we go.
0:08:35 Let me find one that is.
0:08:37 How many cocoons do you have on your desk?
0:08:39 You just put one down and picked up another one.
0:08:42 We have, we are full of cocoons.
0:08:43 So I’m holding it.
0:08:43 Okay.
0:08:45 Tell me about it.
0:08:45 It’s white.
0:08:47 It’s white, white, white, right?
0:08:49 It’s snow white, it looks on the picture.
0:08:56 So it’s a snow white, giant, giant, yep, a giant bean.
0:08:58 Yeah, it’s bigger than a bean.
0:08:59 I’m trying to think, what is that size?
0:09:04 Like if you smushed a ping pong ball into an oblong shape, would it be about that size?
0:09:05 Yeah, about that size.
0:09:07 And you’re holding it by a thread.
0:09:09 Is that a little silken thread that you’re holding it by?
0:09:10 I can’t even see it.
0:09:11 It’s invisible to me.
0:09:13 Yeah, I’m trying to figure out.
0:09:15 There, you can kind of see it now, maybe.
0:09:17 I mean, it’s cool that it’s invisible.
0:09:19 It’s magic.
0:09:21 It’s like a spider web, right?
0:09:26 In fact, spider webs are quite similar, but it’s hard to breed spiders, right?
0:09:27 That’s what I read.
0:09:31 So spiders cannot be domesticated, but caterpillars can.
0:09:33 There are billions of these cocoons.
0:09:34 Yeah.
0:09:37 There are a lot, a lot, a lot of these cocoons.
0:09:42 But the remarkable thing is that each cocoon is an engineering wonder, because if you take
0:09:46 the cocoon and you unwind it, so you wash the glue away that the worms use to keep it
0:09:52 together, or the caterpillars use to keep this together, and you pull, you have almost one
0:09:53 kilometer of uninterrupted thread.
0:09:58 So 10 micron thread that is composed by two silk fibers that are held together.
0:10:01 The 10 microns means about a tenth of the diameter of your hair.
0:10:07 Each fiber is composed by two individual fibers that are held together by that glue that I mentioned
0:10:11 before, because there are two spinning glands in the caterpillar.
0:10:16 And then all held together in this non-woven format that is extremely resilient.
0:10:19 It’s something that you just can’t tear.
0:10:22 And think, there’s no weave in here.
0:10:26 It’s just a worm that is building up layer by layer by layer as it’s building this cocoon.
0:10:28 It’s like additive manufacturing.
0:10:29 It’s like 3D printing.
0:10:30 Yeah.
0:10:31 It is absolutely that.
0:10:33 This is a biological 3D printer.
0:10:38 It’s a filamentary 3D printer that builds a cocoon from the inside, too.
0:10:42 Yeah, the caterpillars on the inside doing it.
0:10:48 So, okay, so there is this incredible natural context to begin with, this incredible thing
0:10:49 that the silkworm does.
0:10:55 And then on top of that, we have the kind of innovation and optimization of whatever, a thousand
0:11:00 plus years of farming and, you know, commercial evolution.
0:11:06 And then you kind of walk onto the stage and you realize, oh, this stuff is really cool.
0:11:09 And you start playing with it.
0:11:14 And let’s talk about some of the things that have come out of it, right?
0:11:16 It’s not purely academic work.
0:11:17 There have been commercial spinoffs.
0:11:25 So the important qualities of the material fabrication process that open up an endless kit of material
0:11:31 wonder are the fact the end formats of material you can eat, you can implant in the body, you
0:11:37 can mix things into this glass of water and silk, mix things that are delicate biologically,
0:11:42 and you can preserve them, and then you can control the degradation of the materials.
0:11:47 You can dip them in water and they dissolve immediately, or you can dip them in water and
0:11:48 they’ll stay put for years.
0:11:51 Just depending on how you build it, essentially.
0:11:53 How you put the proteins together.
0:11:59 It’s just imagine a bunch of little Lego pieces that are floating around, and depending on how
0:12:04 hard you press it, the material lasts more or less, and you can control the sizes of the
0:12:06 bricks that you put in the solution and how they’re pressed together.
0:12:12 And so to a material scientist, having these functional aspects in a material just is mind
0:12:18 blowing, because you can start really imagining what, if you look at all of the materials that
0:12:23 surround you and you start saying, well, what if I could plant this in my garden?
0:12:24 What if I could eat it?
0:12:26 What if I could put biological communicators inside it?
0:12:28 What if I could put chemistries inside here?
0:12:33 That are very difficult to put in by other means.
0:12:36 So then this just opens up a world of craziness.
0:12:40 Of delightful craziness, right?
0:12:41 Good craziness.
0:12:48 I think the thing that I still find myself very surprised by is that after now nearly 20
0:12:54 years of working with this material, I think I’m still as excited about the potential of this
0:12:56 material as I was on day one.
0:13:05 Still to come on the show, using silk to find a better way to deliver vaccines, and also
0:13:07 using silk to help preserve fruits and vegetables.
0:13:10 Also, more things to do with silk.
0:13:22 What’s something that is in the world based on your work?
0:13:28 One of the companies that is called Vaxxas is now using silk-based technology to do microneedle
0:13:31 patches with therapy that doesn’t need to be refrigerated.
0:13:37 So imagine just putting on a Band-Aid rather than going to a place to get an injection and
0:13:41 not having to worry about storing your therapy in the fridge.
0:13:43 Particularly important in the developing world, right?
0:13:45 We take the cold chain for granted here.
0:13:47 And yes, it’s a hassle to go to the pharmacy and get a shot.
0:13:52 But like, there are parts of the world where like, you know, the vaccine has to be called
0:13:55 from the time it’s made until it goes into your arm, essentially.
0:13:55 Yes.
0:13:58 So it has to be in a truck and a ship and everywhere.
0:14:00 It has to stay cold and you have to have reliable power.
0:14:03 And there are big parts of the world where that just doesn’t exist, right?
0:14:06 So it actually is a real problem on a global scale.
0:14:10 I would argue also that it potentially could become even more profitable.
0:14:15 I believe that there’s a lot of opportunities still out there for these classes of material
0:14:17 to be, to generate an incredible amount of revenue.
0:14:20 I mean, do you mean just because it’s cheaper?
0:14:22 Because if you don’t have to keep it cold, it’s more efficient?
0:14:26 Or like, what makes you think of, or just because people prefer, what makes, like, I’m interested.
0:14:29 I just, what makes you think of that here in the conversation?
0:14:35 I think that the functional surprise is what makes this an appealing product and it makes
0:14:36 it economically viable.
0:14:42 I think that having, that trying to substitute materials one for one is very difficult given
0:14:44 the sophistication of what we have today.
0:14:49 But I think that if your material manages to do something unexpected, it brings more value
0:14:50 to a person.
0:14:52 So you’re saying it’s not just not the cold chain.
0:14:53 It’s, you don’t have to get a shot.
0:14:55 You just put this sticker on your arm.
0:14:57 It’s a collection of things.
0:14:59 And so the jury is out of whether this is true or not.
0:15:05 I think the opportunity is big, but I see also that it requires an enormous amount of dedication
0:15:06 and it requires entrepreneurship.
0:15:11 And that side of it is clearly not your side, it seems, as you’re talking about it.
0:15:13 Well, it can’t be.
0:15:15 There are professors who also start companies.
0:15:16 Yes.
0:15:21 But I think that I’m a big believer in the fact that you have to dedicate your full attention
0:15:23 to something to bring it at its maximum level.
0:15:31 So there’s another thing that people are developing based on your work and your colleagues’ work
0:15:35 for vocal cords, right?
0:15:38 They call it vocal folds, but it’s basically vocal cords.
0:15:39 Tell me about that.
0:15:45 So for example, one of the examples is that in certain cases, when you lose mechanical properties
0:15:51 in your vocal fold, your vocal cords are not able to vibrate anymore and you lose your capacity
0:15:52 to speak.
0:15:58 And so one of the strategies would be to restore the strength of the vocal fold so that you give
0:16:00 mechanical fortitude to that.
0:16:06 So we studied this formulation where imagine that you have a dense injectable jello that comes
0:16:13 and stays and stays put in some place and mixes with your native tissue and makes it more for…
0:16:13 I see.
0:16:14 Okay.
0:16:20 So one of the companies that took the gel technology out studied this and they came up with an injectable
0:16:26 format that restores the mechanical properties of the fold and actually gives the capacity of the
0:16:27 patients to speak again.
0:16:29 This is an FDA-approved therapy.
0:16:30 So it worked.
0:16:32 So it worked.
0:16:34 So this is something that you can get today.
0:16:37 Food preservation.
0:16:42 Somebody’s working on using some silk-based technology to make fresh food stay good longer.
0:16:43 Tell me about that.
0:16:48 So it turns out that the silk liquid is very good at coating objects.
0:16:54 And if you take, for example, a strawberry and you dip it in water and silk, silk coats the
0:16:58 strawberry with a thin layer of material that acts as a fruit preservative.
0:17:04 And it’s very effective to prolong the shelf life at room temperature of materials by a week
0:17:05 or a couple of weeks.
0:17:08 And then I guess it depends on what you use it on.
0:17:10 And every food has its own story.
0:17:15 At the time, we, in the lab, we tried it on bananas and on strawberries.
0:17:21 And we saw that at room temperature, we could keep bananas and strawberries fresh for an extra
0:17:23 week, 10 days or something like that.
0:17:29 And so where is that sort of product in the arc of commercialization, this silk-based fruit,
0:17:31 you know, preservative?
0:17:35 Honestly, I think that this is a question for the company itself.
0:17:40 But I know that some product has been successfully applied to leafy greens.
0:17:45 And I think that the use case there is the ability to enhance logistics.
0:17:49 Give you more time to get the greens from the farm to the table.
0:17:50 Exactly.
0:17:54 From point A to point B and without refrigeration, which is a big deal.
0:17:54 Okay.
0:17:56 Tell me what you’re working on now.
0:17:58 What are we working on now?
0:18:00 We’re working on sensing a lot.
0:18:05 We have friends that design proteins that are very, very sensitive and very, very specific.
0:18:12 So there are possibilities of giving formats to say things, for example, that detect hormones.
0:18:18 So one of the things that we did recently was to make an ink with a design or a protein, if
0:18:23 you will, that was very sensitive and very specific to human estrogen receptor too, which is one
0:18:26 of the hormones that is responsible for breast cancer.
0:18:32 So you start imagining things like painting and the inside of a bra.
0:18:38 So you have a monitor of recurrence, for example, or you have a monitor for breast cancer.
0:18:42 We did the same thing with toxins like botulin and hepatitis B.
0:18:48 And so all of these things become very powerful when you have them in these different formats
0:18:49 that are very unexpected.
0:18:59 So the core thing you have ultimately with the silk is this benign stabilizing force, right?
0:19:02 That’s the thing you’re applying in all these different detection settings.
0:19:02 Is that right?
0:19:12 A way to take whatever essentially detectors, these protein detectors that might, whatever,
0:19:14 decompose in other settings.
0:19:17 You’re stabilizing them in a very kind of safe, benign way.
0:19:21 That seems like the core thing that is happening in all these different use cases you’re describing.
0:19:21 Is that right?
0:19:23 That is true.
0:19:27 But the other thing that is very important is that you stabilize these, and that’s the
0:19:28 functional part.
0:19:29 But then you shape it.
0:19:31 And the shapes are very, very technological.
0:19:36 So the other thing that we’re working on that is very exciting is how to control silk on the
0:19:39 nanoscale and actually have these things very precisely localized.
0:19:44 And that can lead to really nice interfaces with, for example, with semiconductors.
0:19:47 Say a little more about that one.
0:19:53 So we had a recent paper where we showed that in a transistor, we can put a thin layer of silk
0:19:59 within the transistor, and we can use the state of silk to change the way that the transistor
0:20:00 switches.
0:20:01 Huh.
0:20:04 Switches, which is the fundamental thing a transistor does.
0:20:06 Goes from on to off, basically.
0:20:07 That’s right.
0:20:13 So if you could imagine this multiplied by a trillion transistors, it would be a very
0:20:18 powerful way to sense things, for example, or to analyze things.
0:20:18 Yeah.
0:20:20 Why not?
0:20:28 So just to land the main part of the conversation here, you’ve been working with silk for almost
0:20:29 20 years.
0:20:35 Like, if you sort of zoom out and look at the big picture arc of your work, what do you come
0:20:36 away with?
0:20:39 There are two main things, I think.
0:20:43 One is a thing that comes from wonder and surprise.
0:20:50 And I think that the more you look at things around you and you interpret and you are amazed
0:20:55 by the things around you, the more you learn about them, the more inspired you are, I would
0:20:56 say.
0:21:02 And then the other thing that I would say is that natural systems, natural materials have
0:21:08 an unbelievable degree of hierarchical sophistication.
0:21:16 And by that, I mean, they are so exquisitely engineered at all scales to provide very simultaneous
0:21:19 functions that are technologically incredibly relevant.
0:21:24 You know, so like the way that they manage energy, the way that they repel infection, the way
0:21:31 that they are super hydrophobic, the way that they’re resilient by being ultra light, their
0:21:35 ability to keep warm and to keep cold, depending on the need.
0:21:39 It’s just, it’s just an endless, the way that they self heal.
0:21:42 It’s like an endless stream of things that is incredible.
0:21:48 Nature has a lot of ideas to do really smart things, to do really meaningful things, to do
0:21:50 profound things and to do very profitable things.
0:21:56 We’ll be back in a minute with the lightning round.
0:22:06 Let’s finish with the lightning round.
0:22:11 What’s one thing about lasers that you wish more people understood?
0:22:14 How profoundly different they are from a light bulb.
0:22:15 Huh.
0:22:18 Say a little more.
0:22:20 I feel like I should know that better.
0:22:20 Tell me.
0:22:24 Lasers are light, and we kind of take for granted that this light travel
0:22:29 travels in a line and gives you a spot, and they’re the same, it’s the same light that
0:22:31 you get from a light bulb, except that the light from the light bulb goes all over the
0:22:33 place, whereas the laser is directional.
0:22:38 And that fact that the laser is directional is amazing material magic.
0:22:39 Uh-huh.
0:22:40 Why?
0:22:44 It gives it order.
0:22:47 So it’s very, very ordered light.
0:22:53 You take something that is chaotic and you make it keep step with time and with space.
0:22:53 Wow.
0:22:58 And it’s very important because it’s at the basis of a lot of things, including self-driving
0:23:02 cars that don’t smash the two into one another, for example, in some cases.
0:23:06 What’s your favorite use of a laser in fiction, in a movie, in a book?
0:23:11 Oh, obviously laser beams on sharks.
0:23:12 Austin Power.
0:23:14 It’s, I mean, it’s Dr. Evil’s.
0:23:15 It’s Dr. Evil.
0:23:16 Good.
0:23:22 Um, so as I understand it, you were an Oppenheimer fellow at Los Alamos.
0:23:23 I was.
0:23:25 What’d you think of the movie Oppenheimer?
0:23:26 Oh, gosh.
0:23:29 Uh, uh, how much time do we have?
0:23:30 This is not a lightning question.
0:23:35 Um, yeah, it was, uh, it was, if I liked it, it’s complicated.
0:23:40 When you were at Los Alamos 20 years ago, were like the, the, you get, you catch any Manhattan
0:23:42 Project vibes or was it just kind of a relic?
0:23:48 Uh, no, I, I think that it’s very present that the history is palpable in, in the lab.
0:23:53 And I think that one of, one of the best things is to go to the museum and see their guest books
0:23:58 and see, and see what people write on the guest book after they’ve gone through the whole story
0:23:59 of the Manhattan Project.
0:24:03 And it’s very, the range of comments is astounding.
0:24:10 It’s from, you know, international atomic agency officers to senators, to a high school football
0:24:16 team, to Japanese visitors, you know, and, and it was at least very much in the culture
0:24:17 of the lab.
0:24:20 And I think that there’s a, I can’t see how, how it wouldn’t be.
0:24:21 Yeah.
0:24:24 True that you wrote a Vespa?
0:24:25 True.
0:24:27 You still write a Vespa?
0:24:29 Not often.
0:24:29 I do.
0:24:32 I own one, but it’s gathering a lot of dust.
0:24:35 You think Vespas are overrated or underrated?
0:24:40 Oh, that’s a, that’s, I’m not gonna, I’m not gonna, I’m not gonna even comment on that.
0:24:42 I think they, I think, I think they look great.
0:24:52 Lorenzo Omenero runs the Silk Lab at Tufts University.
0:24:56 Today’s show was produced by Gabriel Hunter Chang.
0:25:01 It was edited by Lydia Jean Cott and engineered by Sarah Bruguer.
0:25:04 You can email us at problem at Pushkin.fm.
0:25:09 I’m Jacob Goldstein, and we’ll be back next week with another episode of What’s Your Problem?
0:25:09 What’s Your Problem?
Fiorenzo Omenetto is a professor of biomedical engineering at Tufts University and the director of Silklab. Fiorenzo’s problem is this: How do you turn a material people have been using for thousands of years into useful, cutting edge tools that improve everything from vaccine delivery to food waste?
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