WEBVTT - Silk of the Spider, Thread of the Future 0:00:03.120 --> 0:00:06.000 Welcome to Stuff to Blow your Mind from how Stuff 0:00:06.000 --> 0:00:13.920 Works dot com. Hey, welcome to Stuff to Blow your Mind. 0:00:13.960 --> 0:00:16.360 My name is Robert Lamb, and I'm Julie Douglas. Julie, 0:00:16.400 --> 0:00:19.000 do you remember the myth of a ratney? Oh? Yes, 0:00:19.040 --> 0:00:23.040 I do. It's a great one, right, because it follows 0:00:23.040 --> 0:00:28.600 a familiar pattern. Right. You begin with a particularly skilled human, right, 0:00:28.840 --> 0:00:32.319 a great mortal that has just a wondrous talent at 0:00:32.320 --> 0:00:36.839 her disposal. A rackney. She's just a wonderful Weaver's an 0:00:36.840 --> 0:00:40.199 expert weaver, just creates these beautiful tapestries, right, puffed up 0:00:40.200 --> 0:00:43.080 with pride, I bet, But of course, yeah, In fact, 0:00:43.120 --> 0:00:46.760 she ends up boasting of her skills, and either, depending 0:00:46.760 --> 0:00:50.440 on what account you're looking at, either she actually challenges Athena, 0:00:50.560 --> 0:00:53.160 the Goddess of Wisdom and Crafts, to a weaving competition, 0:00:53.520 --> 0:00:56.520 or she just kind of talks about how great she 0:00:56.600 --> 0:00:59.520 is and how she's better than Athena until Athena steps 0:00:59.600 --> 0:01:02.639 up and uh, you know, and and accepts this challenge. 0:01:03.280 --> 0:01:06.080 And of course this is a terrible idea. Right, You're 0:01:06.080 --> 0:01:09.720 going up against a god who basically like pick axed 0:01:09.720 --> 0:01:12.760 her way out of Zeus's brain, Right, Yeah, and like 0:01:12.800 --> 0:01:15.920 all the Greek gods are are are basically terrible. I mean, 0:01:15.920 --> 0:01:20.800 they're they're vain, they're petty, they're powerful, and uh, and 0:01:21.040 --> 0:01:23.800 yet she ends up in this competition and then it 0:01:23.800 --> 0:01:26.520 just gets it gets even worse from there. Um in 0:01:26.640 --> 0:01:32.440 Ovid's telling, Athena's resulting tapestry illustrates past incidents where the 0:01:32.520 --> 0:01:36.520 gods punished more mortals for their arrogance and uh. And 0:01:36.520 --> 0:01:40.959 then Arachne responds by weaving in accounts of just how 0:01:41.160 --> 0:01:45.360 massively abusive and just what kind of misleading jerks the 0:01:45.440 --> 0:01:50.400 gods are towards humans. So, depending on which account you 0:01:50.400 --> 0:01:53.480 look at, either Athena wins because she is a god 0:01:53.560 --> 0:01:56.520 and no matter how great your mortal skill, you're gonna 0:01:56.520 --> 0:02:01.520 get trump by a god. Or Athena notices that arachney 0:02:01.520 --> 0:02:04.639 skill is actually superior to hers, and out of spite 0:02:04.760 --> 0:02:07.600 she just kind of rage quits the entire competition. And 0:02:07.640 --> 0:02:11.800 in either case she curses Athena and her descendants for 0:02:11.800 --> 0:02:16.840 forever turning them into these minuscule web slinging arachnids that 0:02:16.919 --> 0:02:21.480 we know and love today. And what is interesting about 0:02:21.520 --> 0:02:25.800 that is that in some ways humans are still trying 0:02:25.840 --> 0:02:30.360 to extend out this metaphor of trying to manipulate nature 0:02:30.520 --> 0:02:34.200 for their own gain or go up against it. So 0:02:34.320 --> 0:02:38.079 here's one from way back, and then we'll talk more 0:02:38.080 --> 0:02:40.760 recently how we have been trying to do this, all right, 0:02:40.800 --> 0:02:44.600 So we have one Francois xavier A ban Sae Hilaire, 0:02:45.320 --> 0:02:48.959 who it turns out, took silk and he tried to 0:02:49.120 --> 0:02:52.919 do what the gods what nature did, and he tried 0:02:52.960 --> 0:02:54.919 to extract it and weave it. And in fact he 0:02:55.000 --> 0:02:57.919 took the silk he boiled their cocoons, extracting the threads 0:02:57.960 --> 0:03:01.200 with combs to make socks and gloves. And then in 0:03:01.320 --> 0:03:07.000 the early nineteenth century along came Jesuit priest Ramondo Maria Tremor, 0:03:07.600 --> 0:03:11.160 who discovered that threads extracted from the spider itself produced 0:03:11.160 --> 0:03:14.320 a higher quality silk. And there's an eighteen oh seven 0:03:14.440 --> 0:03:18.239 engraving showing his extraction device, and we're looking at it 0:03:18.400 --> 0:03:25.839 right now. Uh, it kind of looks like a spider guillotine. Yes, 0:03:26.040 --> 0:03:29.799 it looks a little nefarious, like I'm instantly sympathizing with 0:03:29.919 --> 0:03:32.399 the spider here, Yeah, because you see that its head 0:03:32.520 --> 0:03:35.080 is trapped in there in this little half moon device. 0:03:35.160 --> 0:03:38.520 It's tiny, and it's abdomen is hanging out, and there's 0:03:38.520 --> 0:03:43.360 a winding machine drawing out a continuous strand from it. Yeah, 0:03:43.400 --> 0:03:45.480 which instantly makes me think of the paintings of the 0:03:45.760 --> 0:03:49.240 windlass of the Rasmus. The spindle that was used to 0:03:49.360 --> 0:03:52.160 draw Rasmus is guts out of his body. So it 0:03:52.480 --> 0:03:54.640 looks very much like a torture instrument. Yes, true, right 0:03:54.720 --> 0:03:57.880 is very nefarious looking, but it's illustrative of the fact 0:03:58.000 --> 0:04:02.360 that even with this tiny device, it's incredibly labor intensive. 0:04:03.160 --> 0:04:05.280 And while we now have the technology to make this 0:04:05.400 --> 0:04:08.560 an easier process, and we have synthetic materials that try 0:04:08.640 --> 0:04:12.480 to mimic silk, we humans are still laboring, still pulling 0:04:12.920 --> 0:04:16.000 at the strings of silk. But now it's not in 0:04:16.160 --> 0:04:20.320 service of our sartorial desires. It's in service of what 0:04:20.480 --> 0:04:23.960 we might think of ours, our scientific desires. Yeah. But 0:04:24.120 --> 0:04:27.080 still a ragney, she doesn't give up her secrets easily. 0:04:27.480 --> 0:04:29.640 She does not. So in this episode, we're going to 0:04:29.720 --> 0:04:32.960 talk a bit about what silk is, what spider silk 0:04:33.000 --> 0:04:36.480 in particular is, and why it's such a stellar um 0:04:37.080 --> 0:04:39.640 engineering feat, and then we're going to talk about the 0:04:39.720 --> 0:04:43.880 various ways that that that humans continue to try and 0:04:44.760 --> 0:04:47.920 grasp that secret of the silk from the spiders, how 0:04:48.000 --> 0:04:49.680 to how we try to mimic it and all the 0:04:49.800 --> 0:04:53.239 various uses that we have for it in our modern 0:04:53.279 --> 0:04:55.520 scientific world. That's right. And it's not just spiders. The 0:04:55.640 --> 0:04:58.760 silkworms so of course, are a huge fixture in this. 0:04:59.320 --> 0:05:01.640 That's right because we uh start off by just talking 0:05:01.640 --> 0:05:04.360 about what silk is, and in defining silk, we really 0:05:04.520 --> 0:05:06.440 need to start more on the insects side of things, 0:05:06.960 --> 0:05:09.880 uh than the arachnet. For the most part, silk is 0:05:09.920 --> 0:05:14.599 a fine, continuous protein fiber produced by various insect larva 0:05:14.920 --> 0:05:17.680 for cocoons, uh. And it's really only produced by a 0:05:17.920 --> 0:05:20.920 few groups in the insect world. And we also refer 0:05:21.040 --> 0:05:26.520 to silk as a bio polymer now. In insects, silk 0:05:26.600 --> 0:05:30.720 originates as a stored protein liquid and modified saliva glands 0:05:30.839 --> 0:05:34.480 located in the insect's head. From here it transports via 0:05:34.560 --> 0:05:38.840 small tubes to the spinneret structure that protrudes beneath the 0:05:38.920 --> 0:05:41.600 mouth parts on the underside of the head of a 0:05:41.680 --> 0:05:45.120 given insect. In the case of spiders, however, as we'll discuss, 0:05:45.200 --> 0:05:47.720 the spinneret is backloaded on the end of the abdomen 0:05:48.200 --> 0:05:50.880 instead uh And we'll get to the spiders in a bit. 0:05:51.000 --> 0:05:53.760 But as far as the insects go, the most common 0:05:53.880 --> 0:05:56.960 use again is cocooning. That's to contain and protect a 0:05:57.040 --> 0:06:00.880 defenseless pupil stage of the insect or and or to 0:06:01.000 --> 0:06:03.000 hold it in place on a leaf or a stem, 0:06:03.920 --> 0:06:07.040 and also some months build tints out of the material 0:06:07.160 --> 0:06:10.719 as well. Cocoon is spun from a single thread of silk. 0:06:11.000 --> 0:06:13.720 It might be just pure silk depending on the species, 0:06:13.960 --> 0:06:16.840 or it might involve bits of soil or leaf litter 0:06:17.320 --> 0:06:20.080 uh that are caught up in the silk strand as well. 0:06:21.080 --> 0:06:23.599 So let's look a little closer at the silkworm, which 0:06:23.720 --> 0:06:27.520 is the larva or caterpillar of the domesticated silk moth 0:06:27.760 --> 0:06:31.480 called bombyx mori, which is Latin for silkworm of the 0:06:31.560 --> 0:06:34.480 mulberry tree. In fact, there's a Chinese proverb that says, 0:06:34.839 --> 0:06:39.960 with time and patients, the mulberry leaf becomes a silk gown. Now, 0:06:40.000 --> 0:06:42.800 the silkworm was once native to China, but now is 0:06:42.839 --> 0:06:46.600 completely domesticated. One cocoon consists of a single thread that 0:06:46.800 --> 0:06:49.560 is about one thousand to three thousand feet long, that's 0:06:49.600 --> 0:06:55.720 three nine hundred meters. And the manipulation of silkworm, the 0:06:55.800 --> 0:07:01.760 domestication goes back years. And there's a legend that Lei Zu, 0:07:02.480 --> 0:07:04.760 wife of the Yellow Emperor, was drinking tea when a 0:07:04.800 --> 0:07:09.000 cocoon fell from a mulberry tree into her steaming cup 0:07:09.120 --> 0:07:13.440 of tea and began to unravel. Yes, she was amazed 0:07:13.560 --> 0:07:18.120 by its luminosity and strength, and she gathered more and 0:07:18.280 --> 0:07:23.520 made silk, and China began to export silk and two 0:07:23.680 --> 0:07:27.760 hundred b c e so much so that the Silk Road, 0:07:28.160 --> 0:07:30.720 the famous network of trade routes, was created and stretched 0:07:30.720 --> 0:07:34.160 from China to the Mediterranean, Africa and Middle East in Europe. 0:07:35.040 --> 0:07:38.920 And the origin of silk was really closely guarded, right 0:07:38.960 --> 0:07:41.400 because this is the this is the lifeblood of China 0:07:41.440 --> 0:07:45.800 at the time. But in five and fifty se some 0:07:46.120 --> 0:07:50.120 some wily sly monks who had traveled to China brought 0:07:50.200 --> 0:07:55.000 back silkworm eggs, and the end of the West was 0:07:55.080 --> 0:07:59.760 forever changed with silk at its disposal. Indeed, now it's 0:08:00.160 --> 0:08:03.600 rate as insects. Silk is as great as the silkworm. 0:08:03.680 --> 0:08:06.840 Silk is. None of these guys can really match the 0:08:06.920 --> 0:08:12.640 arachnids in terms of just pure engineering genius of the thread. Um. 0:08:13.880 --> 0:08:15.760 I mean, they're just in a class all their own. 0:08:15.960 --> 0:08:18.720 So the thing about the spiders, as we've alluded to, 0:08:19.120 --> 0:08:22.400 is that scientists are continuing to study spider silk making 0:08:22.800 --> 0:08:25.240 and UH and trying to get all the valuable details 0:08:25.320 --> 0:08:26.800 out of it. And we still have a lot of 0:08:26.920 --> 0:08:31.400 questions regarding exactly how it all comes together. UM. But 0:08:31.840 --> 0:08:34.959 here the basics as we understand it. Spiders, like the 0:08:35.040 --> 0:08:38.480 like insects, um like the silkworms, have a special special 0:08:38.559 --> 0:08:42.520 glands to secrete silk proteins dissolved in a water based solution. 0:08:42.720 --> 0:08:46.439 The spider pushes the liquid solution through long ducts, leading 0:08:46.480 --> 0:08:51.320 to microscopic UH bigots on the spiders spinnerets, and generally 0:08:51.360 --> 0:08:54.120 there are two or three spinneret pairs located in the 0:08:54.160 --> 0:08:57.320 rear of the admin. Furthermore, each spigot has a valve 0:08:57.440 --> 0:09:01.280 that controls the thickness and speed of the extruded material. 0:09:02.120 --> 0:09:05.520 So already we're seeing like these different layers of complexity 0:09:06.200 --> 0:09:08.120 that are in play when it comes to just pushing 0:09:08.200 --> 0:09:10.760 out that that layer of silk. I think it's easy 0:09:10.800 --> 0:09:13.319 to fall into the trap of thinking of spider silk 0:09:13.520 --> 0:09:16.000 as kind of like silly string, right, Like there's just 0:09:16.120 --> 0:09:18.360 a gland, they squeeze it out, and they just squeeze 0:09:18.400 --> 0:09:20.439 out this thread, and yes, there's some sort of a 0:09:20.520 --> 0:09:22.679 you know, a hardening of the liquid as it comes out, 0:09:23.200 --> 0:09:26.079 but we think, well, there's nothing more to that. But 0:09:26.280 --> 0:09:29.679 really we're talking about a really intense engineering feet just 0:09:29.760 --> 0:09:34.079 at the the construction of the material itself. As the 0:09:34.200 --> 0:09:37.199 spigots pull these silk molecules out of the ducks and 0:09:37.280 --> 0:09:39.720 excrewed them and extrude them into the air, the molecules 0:09:39.760 --> 0:09:43.040 are stretched out and linked together to form long strands, 0:09:43.520 --> 0:09:47.120 and then the spinnerettes wind the strands together to form 0:09:47.200 --> 0:09:50.480 the sturdy silk fiber itself. And this is where it 0:09:50.480 --> 0:09:53.880 gets even crazier, because most spiders have multiple silk glands 0:09:53.920 --> 0:09:57.120 in their body, which secrete different types of silk material 0:09:57.280 --> 0:10:02.160 optimized for different purposes. By winding different silk varieties together 0:10:02.360 --> 0:10:06.240 in varying proportions, uh, spiders can form a wide range 0:10:06.320 --> 0:10:09.079 of fiber material. So it's not just one type of 0:10:09.200 --> 0:10:12.000 ciders a spider silk that's coming out. There are varying 0:10:12.160 --> 0:10:15.360 spider silks depending on what their purposes. They can vary 0:10:15.440 --> 0:10:19.440 fiber consistency by adjusting the spigots from smaller to larger strands, 0:10:20.040 --> 0:10:22.840 and sometimes they'll create a silk strand consisting of an 0:10:22.880 --> 0:10:25.719 inner core with an outer tube around it. Uh, And 0:10:25.880 --> 0:10:29.000 they might apply various coatings such as a waterproof coating 0:10:29.080 --> 0:10:32.319 or a sticky layer, depending on what the use is. 0:10:32.880 --> 0:10:36.960 So so again, when it comes to spider silk, when 0:10:37.000 --> 0:10:39.199 they're creating it, that the purpose of the silk is 0:10:40.040 --> 0:10:43.720 reflected in the actual construction of the silk thread itself, 0:10:44.520 --> 0:10:48.040 which is amazing, especially if you bump this up against 0:10:48.080 --> 0:10:50.079 the silkworm and nothing against the silkworm. They're doing a 0:10:50.120 --> 0:10:52.640 pretty cool job there with making their cocoon, right, But 0:10:52.760 --> 0:10:55.280 that's sort of like, here's this one thing I can do, 0:10:55.640 --> 0:10:58.559 whereas a spider is more like its own three D 0:10:58.720 --> 0:11:02.680 printer exactly. I think that's a fabulous comparison. Yeah, I mean, 0:11:02.720 --> 0:11:06.120 it's varying the type of product that it's creating. And 0:11:06.280 --> 0:11:08.920 the best way to really examine this is to look 0:11:09.080 --> 0:11:12.679 at the anatomy of a web, because I remember, above 0:11:12.720 --> 0:11:15.920 all else, spiders are predators, and so they've come up 0:11:15.960 --> 0:11:19.520 with this elaborate way to catch their dinners. Now, they 0:11:19.600 --> 0:11:22.560 will initially just cast a silk line out into the wind, 0:11:22.640 --> 0:11:25.599 and when it senses that it's caught upon something, it 0:11:25.679 --> 0:11:28.840 will cinch a starting point and use that connection as 0:11:28.880 --> 0:11:32.280 a bridge, walking across it as it creates a loose 0:11:32.640 --> 0:11:35.520 silk hanging from the starting and ending points of this 0:11:35.760 --> 0:11:38.319 bridge is created, so at that point it pulls pulls 0:11:38.720 --> 0:11:41.640 down the silk time. It creates a kind of y configuration. 0:11:42.360 --> 0:11:46.040 It then creates anchor points and structural threads, laying out 0:11:46.200 --> 0:11:49.000 radius points from the center of the web of the threads. 0:11:49.280 --> 0:11:53.480 So then you have the various different types of thread 0:11:53.559 --> 0:11:56.720 being spun. Here, you have a non stick auxiliary spiral 0:11:56.880 --> 0:12:01.200 that's created as well as a second stick auxiliary one, 0:12:01.280 --> 0:12:04.520 so the spider has its own smooth path to tread 0:12:04.600 --> 0:12:08.120 upon while ensuring that the web is good and sticky elsewhere. 0:12:09.080 --> 0:12:13.360 And there are various I mean, there are tons of 0:12:13.440 --> 0:12:17.880 different types of webs and dizzying and their complexity. Right, 0:12:17.960 --> 0:12:20.920 they're beautiful to look at. But one that I wanted 0:12:20.960 --> 0:12:23.960 to point out is not even functioning as a true web, 0:12:24.080 --> 0:12:29.240 and this is via trapdoor spiders who use their webs 0:12:29.240 --> 0:12:31.920 in a really ingenious way. First they dig a tunnel, 0:12:31.960 --> 0:12:34.640 which they smooth out with a mixture of saliva and earth. 0:12:36.160 --> 0:12:38.240 Then they fit the opening to the tunnel with a 0:12:38.320 --> 0:12:40.480 trap door, and it's made out of spider silk, and 0:12:40.520 --> 0:12:44.599 it can be fitted exactly to the dimensions with a 0:12:44.760 --> 0:12:48.520 beveled edge like that's craftsmanship, or it can just have 0:12:48.600 --> 0:12:50.760 a sheet of silk and dirt, and then the top 0:12:50.840 --> 0:12:52.880 of the trapdoors tricked out with debris so that it 0:12:52.960 --> 0:12:56.679 easily blends in. So this tunnel gives the spider refuge. 0:12:56.880 --> 0:12:58.760 It also gives them a place to raise their young 0:12:58.920 --> 0:13:04.440 end and also in the background, serves as this device 0:13:04.600 --> 0:13:08.080 to let the spider know that, you know, there's prey around. 0:13:08.200 --> 0:13:12.440 And it does this that trapdoor by vibrating, and once 0:13:12.520 --> 0:13:17.040 the spider detects that, it can easily rush out, pull 0:13:17.760 --> 0:13:20.959 in that prey into its hole and then chomp on it. 0:13:21.040 --> 0:13:22.880 And it's kind of we were talking about it earlier. 0:13:22.920 --> 0:13:26.319 I was like, Hey, I'm a little bit I kind 0:13:26.320 --> 0:13:28.720 of don't want to necessarily put this upon the spiders 0:13:28.760 --> 0:13:31.080 trapped or spider, but it feels a little bit serial 0:13:31.240 --> 0:13:34.120 killer to me. Yeah, I mean that that's kind of 0:13:34.160 --> 0:13:37.360 the vibe of the spider right now. As you mentioned, 0:13:37.360 --> 0:13:41.959 their various uses for the silk material, various structures that 0:13:41.960 --> 0:13:44.079 are created by the spiders, and we discussed some of 0:13:44.200 --> 0:13:46.920 those in our episode It's a Trap, which will include 0:13:46.920 --> 0:13:49.959 a link to on the landing page for this episode. 0:13:50.520 --> 0:13:54.439 But these structures are amazing, and the level of engineering 0:13:54.559 --> 0:13:57.760 is is evident not only in the structure of the 0:13:58.720 --> 0:14:00.880 that they create out of the webbing, it again in 0:14:01.040 --> 0:14:05.000 the uh, the minute structure of the strands themselves. Uh. 0:14:05.200 --> 0:14:10.440 Spider silk is is is particularly great engineering substance because 0:14:10.480 --> 0:14:14.000 it's incredibly strong, but it's also incredibly flexible. Uh. There's 0:14:14.080 --> 0:14:17.679 some varieties that are reportedly five times as strong as 0:14:17.720 --> 0:14:21.280 an equal mass of steel and twice as strong as 0:14:21.320 --> 0:14:24.880 an equal mass of kevlar. So again, it rivals some 0:14:25.000 --> 0:14:29.120 of our key tough materials that we as humans wield 0:14:29.360 --> 0:14:32.920 in the world around us. Now, to understand, you know, 0:14:33.080 --> 0:14:35.200 why it's so strong, we have to look at the 0:14:35.240 --> 0:14:38.960 molecular construction of spider silk itself. According to a two 0:14:39.000 --> 0:14:42.320 thousand eight study from M I. T. The strength lies 0:14:42.400 --> 0:14:47.680 in the specific geometric configuration of structural proteins, which have 0:14:47.840 --> 0:14:51.600 small clusters of weak hydrogen bonds that work cooperatively to 0:14:51.720 --> 0:14:56.520 resist force and dissipate energy. Two twelve University of California 0:14:56.640 --> 0:15:00.520 Riverside study identified the genes and determine the DNA sequence 0:15:00.760 --> 0:15:04.160 for two key proteins in the drag line silk of 0:15:04.240 --> 0:15:06.160 the black widow spider. And and you often see the 0:15:06.240 --> 0:15:08.760 drag line silk is a focused point UH in the 0:15:08.960 --> 0:15:11.480 various studies because of the services the bridge, it has 0:15:11.520 --> 0:15:14.040 to be really strong. So this is the primo material 0:15:14.320 --> 0:15:16.680 when it comes to spider silk UH. And it turns 0:15:16.680 --> 0:15:18.760 out the straight drag line silk is a composite material 0:15:18.800 --> 0:15:22.880 comprised of two different proteins, each containing three regions with 0:15:23.040 --> 0:15:28.000 distinct properties. So you have an amorphous non crystalline matrix 0:15:28.120 --> 0:15:32.880 that's stretchable, giving the silk elasticity. And then embedded in 0:15:32.960 --> 0:15:35.800 the amorphous portions of both proteins are two kinds of 0:15:35.880 --> 0:15:39.840 crystalline regions that toughen the silk. So the resulting composite 0:15:40.160 --> 0:15:44.960 is strong, tough, yet elastic. And and again it's it's 0:15:45.240 --> 0:15:48.560 there and just the minute construction of the thread itself, 0:15:49.120 --> 0:15:51.240 and we humans see it, we admire it, and we 0:15:51.400 --> 0:15:56.040 want it. But commercial production of spider silk from spiders 0:15:56.280 --> 0:16:00.160 is impractical because spiders are jerks right there. They're to 0:16:00.400 --> 0:16:04.320 cannibalistic and territorial for farming. They're not really jerks, but 0:16:04.520 --> 0:16:07.440 you know, they're just not ideal for that purpose. Uh 0:16:07.480 --> 0:16:11.800 And researchers have looked to other organisms, including bacteria, insects, mammals, 0:16:11.840 --> 0:16:17.200 and plants, But those proteins require mechanical spinning and this 0:16:17.640 --> 0:16:21.800 is a task that our friend the silkworm performs naturally 0:16:22.080 --> 0:16:26.600 with those nifty spinneretts. So so what's the researcher to do. Well, 0:16:27.200 --> 0:16:30.040 let's look at Malcolm Fraser Jr. Who in two thousand 0:16:30.120 --> 0:16:34.800 and twelve with his team created a hybrid silkworm to 0:16:35.000 --> 0:16:40.840 do their bidding, one with both silkworm and spider silk proteins, 0:16:40.920 --> 0:16:46.120 and results showed that taking these two proteins um would 0:16:46.160 --> 0:16:50.560 result any tougher than typical silkworm silk. It would be 0:16:50.680 --> 0:16:54.200 as tough as drag line silk um and it would 0:16:54.200 --> 0:16:56.800 be just the right material that you would want to 0:16:56.880 --> 0:16:59.360 try to commercially produce. So why would you do this? 0:16:59.480 --> 0:17:02.880 Why would you mercially produce it um? We'll discuss other 0:17:03.600 --> 0:17:05.639 instances in which you can use it. But when they 0:17:05.680 --> 0:17:08.240 were looking at for this purpose, it was for wound dressings, 0:17:08.840 --> 0:17:15.560 artificial ligments, tendons, tissue scaffolds, micro capsules, cosmetics, and textiles. Okay, Now, 0:17:15.600 --> 0:17:17.760 while some of you have probably heard of these transgenic 0:17:17.840 --> 0:17:20.600 silk worms, I bet even more of you remember the 0:17:20.720 --> 0:17:26.160 transgenic spider goat hybrid, because this really made the rounds, 0:17:26.240 --> 0:17:29.159 especially back in two thousand two. Uh, instantly bringing to 0:17:29.320 --> 0:17:33.560 mind and uh and probably to digital reality. Poorly photoshopped 0:17:33.600 --> 0:17:36.520 images of a goat with like big spider legs coming 0:17:36.560 --> 0:17:40.320 out of its side, right, was photoshopped? Yeah, because because 0:17:40.359 --> 0:17:45.160 the real transgenic goat spider hybrid just looks like a goat. Um. 0:17:45.560 --> 0:17:47.920 This again, it's happening back in two thousand two, researchers 0:17:47.960 --> 0:17:53.200 at Nexia Biotechnologies genetically modified goats using silk producing genes 0:17:53.440 --> 0:17:57.960 from spiders, which just a headline level back in two 0:17:58.040 --> 0:18:02.200 thousand two, it of course instantly sounds Frankensteiny, right, like 0:18:02.280 --> 0:18:04.080 who are these scientists and why are they trying to 0:18:04.160 --> 0:18:07.960 make goat spiders? Um. But at this point in the podcast, 0:18:08.040 --> 0:18:10.159 I think everyone understands what they were going for the 0:18:10.280 --> 0:18:12.680 idea was that you would have a small number of 0:18:12.760 --> 0:18:14.840 goats that would be able to produce a large amount 0:18:14.880 --> 0:18:17.879 of silk material in their milk, which could then be 0:18:18.080 --> 0:18:23.360 used in various UH then could be utilized for various 0:18:23.400 --> 0:18:26.920 purposes as we'll discuss. Essentially, they would be the goats 0:18:26.960 --> 0:18:30.679 will be creating dragline milk. Now, the strands that they 0:18:30.760 --> 0:18:35.080 produced were only as strong as natural spider silk, but 0:18:35.200 --> 0:18:38.440 still it's a start, right UH and and at their 0:18:38.520 --> 0:18:42.199 height next to as Montreal Flock had nearly fifty spider 0:18:42.280 --> 0:18:45.840 goats total. But the company went bankrupt in two thousand nine, 0:18:46.080 --> 0:18:48.320 So you had a couple of transgendent goats that went 0:18:48.440 --> 0:18:52.600 to the Canadian Agricultural Museum, while the rest of them 0:18:52.680 --> 0:18:56.639 went to Utah State University where they're continue to study 0:18:56.720 --> 0:18:58.560 them to this day and figure out how we can 0:18:58.640 --> 0:19:02.200 best utilize a spider goat UM for the for the 0:19:02.280 --> 0:19:05.320 better men of humanity. Now, that's not the only instance 0:19:05.400 --> 0:19:07.880 of a company either going bankrupt or just pulling out 0:19:07.920 --> 0:19:12.600 of the endeavor entirely. And that is because even though 0:19:12.640 --> 0:19:16.879 you you have UM information being uncovered and you have 0:19:17.119 --> 0:19:20.879 the transgenic UH, the ability to mess around with this 0:19:21.000 --> 0:19:23.920 and try to do this in other organisms you still 0:19:24.040 --> 0:19:27.639 have to understand the relationship between spider silk structure and 0:19:27.760 --> 0:19:30.840 its function. And again a lot of companies have tried 0:19:30.880 --> 0:19:34.440 to do this, but it wasn't until researchers from Dalhousie 0:19:34.560 --> 0:19:38.480 University in Nova Scotia took a closer look at the 0:19:38.640 --> 0:19:41.520 mechanism and tried to uncover some piece of information that 0:19:41.600 --> 0:19:44.240 might get them a little bit closer. Now, the first 0:19:44.320 --> 0:19:48.240 step is that they created artificial spider silk to replicate 0:19:48.320 --> 0:19:51.159 the proteins that make up the natural version, in this 0:19:51.359 --> 0:19:56.800 case by recombinantly expressing them in the Bacterium E coli. Now, 0:19:56.880 --> 0:19:59.560 they looked at the key protein and acid informed silk 0:20:00.040 --> 0:20:02.800 called a c sp one and they said, okay, it's 0:20:02.800 --> 0:20:05.360 got three parts. And they said, all right. The protein, 0:20:05.480 --> 0:20:08.480 most of it is repeated sequences of about two hundred 0:20:08.520 --> 0:20:11.879 amino acids, and there are two tales called the N 0:20:12.000 --> 0:20:14.960 and C terminal domains that hang off each end of 0:20:15.040 --> 0:20:18.520 the protein chain. Now, when they took these proteins and 0:20:19.200 --> 0:20:21.879 they chained them together, they found that the chains weren't 0:20:22.040 --> 0:20:26.159 working in unison, but rather as independent units. So that 0:20:26.320 --> 0:20:28.879 was the first clue of how these are actually working 0:20:28.960 --> 0:20:32.760 within spiders. And it was the C terminal domain of 0:20:32.800 --> 0:20:34.639 the protein that was the juncture of the protein that 0:20:34.840 --> 0:20:37.840 determined the strength of the fiber. So when you're talking 0:20:37.920 --> 0:20:40.800 about that spider being in the architect and choosing a 0:20:40.880 --> 0:20:44.199 different type of that type of material, but maybe um 0:20:44.359 --> 0:20:49.639 consistency or strength, that's the C terminal that is controlling that. 0:20:49.800 --> 0:20:53.000 And this was a huge breakthrough, right because it peeled 0:20:53.080 --> 0:20:57.720 away a layer of mystery, and yet there's still so 0:20:57.920 --> 0:21:02.960 much to be learned in the evolution of spider silk. Yeah, 0:21:03.040 --> 0:21:04.560 because then we what do you do with that data? 0:21:04.600 --> 0:21:08.080 Then it just leads to six other questions regarding the 0:21:08.240 --> 0:21:10.879 engineering process that's taking place there. I guess what you 0:21:10.960 --> 0:21:12.879 knew is you look at it in its in its 0:21:12.960 --> 0:21:14.879 form right now and say, oh, what can we deal 0:21:15.000 --> 0:21:17.760 with it? Right? And that's really the the examples we're 0:21:17.760 --> 0:21:20.120 gonna look to next in the podcast are really looking 0:21:20.200 --> 0:21:23.760 more at at possible uh ways that we can use 0:21:24.240 --> 0:21:26.960 the spider silk and the structure of the spider silk 0:21:27.040 --> 0:21:29.080 and in some cases of the structure of the web itself, 0:21:29.440 --> 0:21:33.359 how we can mimic that design in various pursuits. According 0:21:33.400 --> 0:21:35.639 to a two thousand fourteen paper from the University of 0:21:35.680 --> 0:21:39.280 Akron UH spider silk could be used as an inspiration 0:21:39.359 --> 0:21:43.880 to create more efficient and stronger commercial and biomedical adhesives 0:21:44.440 --> 0:21:50.000 that could, for example, potentially attach tendons to bones, bind fractures, etcetera. 0:21:50.000 --> 0:21:52.960 Anytime you need to bring to shoot together and hold 0:21:53.000 --> 0:21:55.520 it in place firmly. And and of course one of 0:21:55.600 --> 0:21:59.159 the advantages here is we'd be using a biosubstance as 0:21:59.200 --> 0:22:02.280 opposed to something that has to be ejected from the 0:22:02.359 --> 0:22:06.400 body or taken out at a later date. UH. In particular, 0:22:06.440 --> 0:22:08.640 with this particular with this study, UH, they were looking 0:22:08.760 --> 0:22:12.320 at the attachment disks that spiders used to attach their 0:22:12.359 --> 0:22:15.920 webs to structure. So the spider pins down an underlying 0:22:16.040 --> 0:22:19.120 thread of silk with additional threads like stitches or staples 0:22:19.200 --> 0:22:22.840 on top of it. UM. But the real engineering feed 0:22:22.880 --> 0:22:26.760 here is that the geometry of the attachment disk, the 0:22:26.840 --> 0:22:30.120 way that they're actually laying down these strands, it creates 0:22:30.160 --> 0:22:34.840 a super strong attachment force using very little material. So 0:22:34.960 --> 0:22:38.520 it's you know, a perfect economic model to try and 0:22:39.000 --> 0:22:42.639 and mimic. So this this particular team led by you 0:22:42.840 --> 0:22:48.240 a professor of polymer science, Ali Dinawala, utilized electro spinning 0:22:48.480 --> 0:22:52.040 to mimic the efficient staple pin method. Now, electro spinning 0:22:52.119 --> 0:22:55.040 is a process by which an electrical charge is used 0:22:55.240 --> 0:22:58.440 to draw very fine fibers from a liquid. And in 0:22:58.520 --> 0:23:01.240 the case of this, uh, this particular experiment, they were 0:23:01.320 --> 0:23:06.040 using polyure thing. Okay, So again, the possible uses here 0:23:06.160 --> 0:23:09.680 include you know binding, uh, you know, tendons back together, binding, 0:23:09.720 --> 0:23:13.840 tends to bone, binding, fractures, etcetera. And you'd be using 0:23:13.920 --> 0:23:16.920 material that can degrade and be reabsorbed by the body. 0:23:17.480 --> 0:23:20.440 Now that's an example of mending the human body. But 0:23:20.720 --> 0:23:24.960 spider silk also shows up when you're talking about essentially 0:23:25.119 --> 0:23:30.440 growing new organs for yourself. And that's because you need 0:23:30.560 --> 0:23:33.000 when you're talking about growing artificial tissues and organs, you 0:23:33.119 --> 0:23:36.520 need some kind of structure or substrate for the entity 0:23:36.640 --> 0:23:40.320 to grow around. And so what could be feather light 0:23:40.560 --> 0:23:44.560 but formidable enough to provide a framework spiderwebs, of course. 0:23:45.720 --> 0:23:48.040 So you have a group of researchers led by Professor 0:23:48.200 --> 0:23:53.080 Constantine A. Glad Say, who heads the Laboratory of Biophysics 0:23:53.200 --> 0:23:56.600 of Excitable Systems m I p T, and they work 0:23:56.680 --> 0:24:01.400 specifically on cardiac tissues. Isolate, a protein used in web 0:24:01.480 --> 0:24:06.160 spinning called spiedroying. What they did is they seated isolated 0:24:06.400 --> 0:24:11.960 neonatal rat cardiac cells on fiber matrices and during the experiment, 0:24:12.040 --> 0:24:14.199