WEBVTT 00:00:01.150 --> 00:00:04.285 So, I love making tools and sharing them with people. 00:00:05.118 --> 00:00:06.508 I remember as a child, 00:00:06.532 --> 00:00:09.825 my first tool I built was actually a microscope 00:00:09.849 --> 00:00:13.521 that I built by stealing lenses from my brother's eyeglasses. 00:00:14.289 --> 00:00:16.076 He wasn't that thrilled. 00:00:16.100 --> 00:00:18.270 But, you know, maybe because of that moment, 00:00:18.294 --> 00:00:19.447 30 years later, 00:00:19.471 --> 00:00:21.359 I'm still making microscopes. 00:00:22.359 --> 00:00:25.658 And the reason I built these tools is for moments like this. NOTE Paragraph 00:00:27.559 --> 00:00:29.979 (Video) Girl: I have black things in my hair -- NOTE Paragraph 00:00:30.003 --> 00:00:32.278 Manu Prakash: This is a school in the Bay Area. NOTE Paragraph 00:00:32.840 --> 00:00:37.304 (Video) MP: The living world far supersedes our imagination 00:00:37.328 --> 00:00:39.295 of how things actually work. NOTE Paragraph 00:00:39.319 --> 00:00:41.770 (Video) Boy: Oh my God! NOTE Paragraph 00:00:43.773 --> 00:00:46.125 MP: Right -- oh my God! 00:00:46.621 --> 00:00:49.622 I hadn't realized this would be such a universal phrase. NOTE Paragraph 00:00:51.123 --> 00:00:52.923 Over the last two years, 00:00:52.947 --> 00:00:54.114 in my lab, 00:00:54.138 --> 00:00:56.213 we built 50,000 Foldscopes 00:00:56.237 --> 00:00:59.147 and shipped them to 130 countries in the world, 00:00:59.171 --> 00:01:01.757 at no cost to the kids we sent them to. 00:01:02.238 --> 00:01:03.481 This year alone, 00:01:03.505 --> 00:01:05.637 with the support of our community, 00:01:05.661 --> 00:01:08.141 we are planning to ship a million microscopes 00:01:08.165 --> 00:01:09.527 to kids around the world. 00:01:10.034 --> 00:01:11.604 What does that do? 00:01:11.628 --> 00:01:15.384 It creates an inspiring community of people around the world, 00:01:15.408 --> 00:01:17.080 learning and teaching each other, 00:01:17.104 --> 00:01:21.194 from Kenya to Kampala to Kathmandu to Kansas. NOTE Paragraph 00:01:21.218 --> 00:01:23.863 And one of the phenomenal things that I love about this 00:01:23.887 --> 00:01:25.443 is the sense of community. 00:01:25.871 --> 00:01:27.263 There's a kid in Nicaragua 00:01:27.287 --> 00:01:31.481 teaching others how to identify mosquito species that carry dengue 00:01:31.505 --> 00:01:33.923 by looking at the larva under a microscope. 00:01:33.947 --> 00:01:36.495 There's a pharmacologist who came up with a new way 00:01:36.519 --> 00:01:38.762 to detect fake drugs anywhere. 00:01:39.402 --> 00:01:41.461 There is a girl who wondered: 00:01:41.485 --> 00:01:43.183 "How does glitter actually work?" 00:01:43.207 --> 00:01:46.926 and discovered the physics of crystalline formation in glitter. 00:01:47.713 --> 00:01:49.318 There is an Argentinian doctor 00:01:49.342 --> 00:01:53.604 who's trying to do field cervical cancer screening with this tool. 00:01:53.628 --> 00:01:57.366 And yours very truly found a species of flea 00:01:57.390 --> 00:02:02.166 that was dug inside my heel in my foot one centimeter deep. NOTE Paragraph 00:02:03.321 --> 00:02:07.578 Now, you might think of these as anomalies. 00:02:07.975 --> 00:02:09.995 But there is a method to this madness. 00:02:10.617 --> 00:02:12.847 I call this "frugal science" -- 00:02:12.871 --> 00:02:16.723 the idea of sharing the experience of science, 00:02:16.747 --> 00:02:18.462 and not just the information. 00:02:19.011 --> 00:02:20.226 To remind you: 00:02:20.250 --> 00:02:22.334 there are a billion people on this planet 00:02:22.358 --> 00:02:24.873 who live with absolutely no infrastructure: 00:02:24.897 --> 00:02:26.511 no roads, 00:02:26.535 --> 00:02:27.917 no electricity 00:02:27.941 --> 00:02:29.727 and thus, no health care. 00:02:30.967 --> 00:02:35.203 Also, there a billion kids on this planet that live in poverty. 00:02:35.700 --> 00:02:37.368 How are we supposed to inspire them 00:02:37.392 --> 00:02:39.714 for the next generation of solution makers? 00:02:40.264 --> 00:02:43.012 There are health care workers that we put on the line 00:02:43.036 --> 00:02:44.954 to fight infectious diseases, 00:02:44.978 --> 00:02:49.435 to protect us with absolutely bare-minimum tools and resources. NOTE Paragraph 00:02:50.584 --> 00:02:52.178 So as a lab at Stanford, 00:02:52.202 --> 00:02:56.139 I think of this from a context of frugal science 00:02:56.163 --> 00:02:58.748 and building solutions for these communities. 00:02:58.772 --> 00:03:03.354 Often we think about being able to do diagnosis under a tree, off-grid. 00:03:03.816 --> 00:03:06.545 I'll tell you two examples today of new tools. 00:03:06.569 --> 00:03:08.374 One of them starts in Uganda. 00:03:08.751 --> 00:03:10.280 In 2013, 00:03:10.304 --> 00:03:14.350 on a field trip to detect schistosomiasis with Foldscopes, 00:03:14.374 --> 00:03:16.932 I made a minor observation. 00:03:16.956 --> 00:03:18.533 In a clinic, 00:03:18.557 --> 00:03:19.896 in a far, remote area, 00:03:19.920 --> 00:03:23.508 I saw a centrifuge being used as a doorstop. 00:03:24.192 --> 00:03:26.583 I mean -- quite literally, the doorstop. 00:03:26.607 --> 00:03:28.333 And I asked them and they said, 00:03:28.357 --> 00:03:30.384 "Oh, we don't actually have electricity, 00:03:30.408 --> 00:03:33.937 so this piece of junk is good as a doorstop." 00:03:34.624 --> 00:03:37.326 Centrifuges, for some of you who don't know, 00:03:37.350 --> 00:03:40.574 are the pinnacle tool to be able to do sample processing. 00:03:40.598 --> 00:03:43.340 You separate components of blood or body fluids 00:03:43.364 --> 00:03:45.824 to be able to detect and identify pathogens. 00:03:46.419 --> 00:03:49.253 But centrifuges are bulky, expensive -- 00:03:49.277 --> 00:03:51.471 cost around 1,000 dollars -- 00:03:51.495 --> 00:03:53.501 and really hard to carry out in the field. 00:03:53.525 --> 00:03:54.682 And of course, 00:03:54.706 --> 00:03:56.140 they don't work without power. 00:03:56.164 --> 00:03:57.556 Sound familiar? 00:03:57.580 --> 00:04:00.128 So we started thinking about solving this problem, 00:04:00.152 --> 00:04:01.702 and I came back -- 00:04:01.726 --> 00:04:03.392 kept thinking about toys. NOTE Paragraph 00:04:03.818 --> 00:04:04.982 Now ... 00:04:06.030 --> 00:04:07.788 I have a few with me here. 00:04:07.812 --> 00:04:09.919 I first started with yo-yos ... 00:04:09.943 --> 00:04:12.574 and I'm a terrible yo-yo thrower. 00:04:12.923 --> 00:04:14.604 Because these objects spin, 00:04:14.628 --> 00:04:15.790 we wondered, 00:04:15.814 --> 00:04:18.171 could we actually use the physics of these objects 00:04:18.195 --> 00:04:19.904 to be able to build centrifuges? 00:04:21.257 --> 00:04:23.747 This was possibly the worst throw I could make. 00:04:24.436 --> 00:04:25.929 But you might start realizing, 00:04:25.953 --> 00:04:28.792 if you start exploring the safe space of toys -- 00:04:28.816 --> 00:04:31.421 we tried these spinning tops, 00:04:31.445 --> 00:04:33.327 and then in the lab, 00:04:33.351 --> 00:04:35.433 we stumbled upon this wonder. NOTE Paragraph 00:04:35.770 --> 00:04:39.256 It's the whirligig, or a buzzer, or a rundle. 00:04:39.280 --> 00:04:41.697 A couple of strings and a little disk, 00:04:41.721 --> 00:04:43.928 and if I push, it spins. 00:04:44.350 --> 00:04:46.694 How many of you have played with this as a kid? 00:04:46.718 --> 00:04:48.566 This is called a button-on-a-string. 00:04:48.590 --> 00:04:50.226 OK, maybe 50 percent of you. 00:04:50.250 --> 00:04:51.808 What you didn't realize -- 00:04:51.832 --> 00:04:54.145 that this little object 00:04:54.169 --> 00:04:58.532 is the oldest toy in the history of mankind ... 00:04:59.007 --> 00:05:00.652 5,000 years ago. 00:05:00.676 --> 00:05:04.375 We have found relics of this object hidden around on our planet. 00:05:05.104 --> 00:05:07.045 Now the irony is, 00:05:07.069 --> 00:05:10.804 we actually don't understand how this little thing works. 00:05:10.828 --> 00:05:12.231 That's when I get excited. NOTE Paragraph 00:05:12.797 --> 00:05:14.878 So we got back to work, 00:05:14.902 --> 00:05:16.692 wrote down a couple of equations. 00:05:17.056 --> 00:05:20.369 If you take the input torque that you put in, 00:05:20.393 --> 00:05:22.497 you take the drag on this disc, 00:05:22.521 --> 00:05:24.426 and the twist drag on these strings, 00:05:24.450 --> 00:05:26.939 you should be able to mathematically solve this. 00:05:26.963 --> 00:05:29.771 This is not the only equation in my talk. 00:05:29.795 --> 00:05:31.627 Ten pages of math later, 00:05:31.651 --> 00:05:34.510 we could actually write down the complete analytical solution 00:05:34.534 --> 00:05:35.808 for this dynamic system. 00:05:36.388 --> 00:05:39.999 And out comes what we call "Paperfuge." 00:05:40.023 --> 00:05:42.567 That's my postdoc Saad Bhamla, 00:05:42.591 --> 00:05:44.258 who's the co-inventor of Paperfuge. 00:05:44.282 --> 00:05:46.527 And to the left, you see all the centrifuges 00:05:46.551 --> 00:05:47.978 that we're trying to replace. NOTE Paragraph 00:05:48.002 --> 00:05:51.709 This little object that you see right here 00:05:52.939 --> 00:05:56.184 is a disc, a couple of strings and a handle. 00:05:56.208 --> 00:05:57.382 And when I spin 00:05:57.940 --> 00:05:59.093 and I push, 00:05:59.117 --> 00:06:00.269 it starts to spin. 00:06:00.293 --> 00:06:02.378 Now, when you realize, 00:06:02.950 --> 00:06:04.345 when you do the math, 00:06:05.579 --> 00:06:08.069 when we calculate the rpm for this object, 00:06:08.093 --> 00:06:12.825 mathematically, we should be able to go all the way to a million rpm. 00:06:12.849 --> 00:06:15.042 Now, there is a little twist in human anatomy, 00:06:15.066 --> 00:06:18.141 because the resonant frequency of this object is about 10 hertz, 00:06:18.165 --> 00:06:19.969 and if you've ever played the piano, 00:06:19.993 --> 00:06:22.087 you can't go higher than two or three hertz. 00:06:22.111 --> 00:06:25.375 The maximum speed we've been able to achieve with this object 00:06:25.399 --> 00:06:27.328 is not 10,000 rpm, 00:06:27.352 --> 00:06:28.956 not 50,000 rpm -- 00:06:28.980 --> 00:06:30.905 120,000 rpm. 00:06:30.929 --> 00:06:33.733 That's equal to 30,000 g-forces. 00:06:33.757 --> 00:06:36.964 If I was to stick you right here and have it spin, 00:06:36.988 --> 00:06:40.417 you would think about the types of forces you would experience. NOTE Paragraph 00:06:40.441 --> 00:06:42.679 One of the factors of a tool like this 00:06:42.703 --> 00:06:45.697 is to be able to do diagnosis with this. 00:06:45.721 --> 00:06:50.001 So, I'm going to do a quick demo here, where -- 00:06:50.442 --> 00:06:54.037 this is a moment where I'm going to make a little finger prick, 00:06:54.061 --> 00:06:56.336 and a tiny drop of blood is going to come out. 00:06:56.360 --> 00:06:58.981 If you don't like blood, you don't have to look at it. 00:06:59.005 --> 00:07:00.344 Here is a little lancet. 00:07:00.368 --> 00:07:02.238 These lancets are available everywhere, 00:07:02.262 --> 00:07:03.785 completely passive. 00:07:03.809 --> 00:07:07.395 And if I've had breakfast today ... 00:07:10.047 --> 00:07:11.534 That didn't hurt at all. 00:07:11.558 --> 00:07:15.542 OK, I take a little capillary with a drop of blood -- 00:07:15.566 --> 00:07:17.825 now this drop of blood has answers, 00:07:17.849 --> 00:07:19.528 that's why I'm interested in it. 00:07:19.910 --> 00:07:23.377 It might actually tell me whether I have malaria right now or not. 00:07:23.401 --> 00:07:25.233 I take a little capillary, 00:07:25.257 --> 00:07:27.382 and you see it starts wicking in. 00:07:27.888 --> 00:07:30.156 I'm going to draw a little more blood. 00:07:32.782 --> 00:07:35.025 And that's good enough for right now. 00:07:35.519 --> 00:07:39.649 Now, I just seal this capillary by putting it in clay. 00:07:43.492 --> 00:07:45.772 And now that's sealed the sample. NOTE Paragraph 00:07:45.796 --> 00:07:47.925 We're going to take the sample, 00:07:47.949 --> 00:07:49.913 mount it on Paperfuge. 00:07:57.092 --> 00:08:00.480 A little piece of tape to make a sealed cavity. 00:08:00.975 --> 00:08:03.870 So now the sample is completely enclosed. 00:08:07.107 --> 00:08:09.400 And we are ready for a spin. 00:08:11.019 --> 00:08:13.060 I'm pushing and pulling with this object. 00:08:13.084 --> 00:08:14.783 I'm going to load this up ... 00:08:16.277 --> 00:08:18.560 And you see the object starts spinning. 00:08:18.584 --> 00:08:20.598 Unlike a regular centrifuge, 00:08:20.622 --> 00:08:24.401 this is a counter-rotating centrifuge. 00:08:24.425 --> 00:08:26.761 It goes back and forth, back and forth ... 00:08:27.221 --> 00:08:29.349 And now I'm charging it up, 00:08:29.373 --> 00:08:31.201 and you see it builds momentum. 00:08:32.185 --> 00:08:34.797 And now -- I don't know if you can hear this -- 00:08:34.821 --> 00:08:36.360 30 seconds of this, 00:08:36.989 --> 00:08:41.314 and I should be able to separate all the blood cells with the plasma. 00:08:41.938 --> 00:08:44.751 And the ratio of those blood cells to plasma -- NOTE Paragraph 00:08:44.775 --> 00:08:46.789 (Applause) NOTE Paragraph 00:08:48.439 --> 00:08:50.774 Already, if you see right here, 00:08:52.206 --> 00:08:53.830 if you focus on this, 00:08:53.854 --> 00:08:56.399 you should be able to see a separated volume 00:08:57.272 --> 00:08:59.130 of blood and plasma. 00:08:59.154 --> 00:09:03.077 And the ratio of that actually tells me whether I might be anemic. NOTE Paragraph 00:09:03.101 --> 00:09:07.138 One the of aspects of this is, we build many types of Paperfuges. 00:09:07.162 --> 00:09:11.628 This one allows us to identify malaria parasites 00:09:11.652 --> 00:09:13.469 by running them for a little longer, 00:09:13.493 --> 00:09:17.059 and we can identify malaria parasites that are in the blood 00:09:17.083 --> 00:09:20.657 that we can separate out and detect with something like a centrifuge. 00:09:20.681 --> 00:09:25.161 Another version of this allows me to separate nucleic acids 00:09:25.185 --> 00:09:28.742 to be able to do nucleic acid tests out in the field itself. 00:09:29.573 --> 00:09:33.917 Here is another version that allows me to separate bulk samples, 00:09:33.941 --> 00:09:35.511 and then, finally, 00:09:35.535 --> 00:09:37.535 something new that we've been working on 00:09:37.559 --> 00:09:42.354 to be able to implement the entire multiplex test on an object like this. 00:09:42.378 --> 00:09:46.715 So where you do the sample preparation and the chemistry in the same object. NOTE Paragraph 00:09:47.540 --> 00:09:48.826 Now ... 00:09:48.850 --> 00:09:50.120 this is all good, 00:09:50.144 --> 00:09:52.051 but when you start thinking about this, 00:09:52.075 --> 00:09:54.164 you have to share these tools with people. 00:09:54.188 --> 00:09:57.570 And one of the things we did is -- we just got back from Madagascar; 00:09:57.594 --> 00:10:00.172 this is what clinical trials for malaria look like -- NOTE Paragraph 00:10:00.196 --> 00:10:01.199 (Laughter) NOTE Paragraph 00:10:01.223 --> 00:10:03.580 You can do this while having coffee. 00:10:03.604 --> 00:10:05.477 But most importantly, 00:10:05.501 --> 00:10:09.563 this is a village six hours from any road. 00:10:10.036 --> 00:10:14.599 We are in a room with one of the senior members of the community 00:10:14.623 --> 00:10:16.136 and a health care worker. 00:10:16.160 --> 00:10:19.657 It really is this portion of the work that excites me the most -- 00:10:19.681 --> 00:10:20.839 that smile, 00:10:20.863 --> 00:10:24.737 to be able to share simple but powerful tools with people around the world. 00:10:25.479 --> 00:10:27.781 Now, I forgot to tell you this, 00:10:27.805 --> 00:10:30.208 that all of that cost me 20 cents to make. NOTE Paragraph 00:10:31.510 --> 00:10:34.392 OK, in the negative time I have left, 00:10:34.416 --> 00:10:36.482 I'll tell you about the most recent -- NOTE Paragraph 00:10:36.506 --> 00:10:37.626 (Laughter) NOTE Paragraph 00:10:37.650 --> 00:10:39.520 invention from our lab. 00:10:39.544 --> 00:10:40.897 It's called Abuzz -- 00:10:41.618 --> 00:10:45.752 the idea that all of you could help us fight mosquitoes; 00:10:45.776 --> 00:10:48.043 you could all help us track our enemies. 00:10:48.067 --> 00:10:52.055 These are enemies because they cause malaria, Zika, chikungunya, dengue. 00:10:52.079 --> 00:10:56.863 But the challenge is that we actually don't know where our enemies are. 00:10:56.887 --> 00:10:59.866 The world map for where mosquitoes are is missing. 00:11:00.303 --> 00:11:02.046 So we started thinking about this. 00:11:02.070 --> 00:11:04.105 There are 3,500 species of mosquitoes, 00:11:04.129 --> 00:11:05.532 and they're all very similar. 00:11:05.556 --> 00:11:06.995 Some of them are so identical 00:11:07.019 --> 00:11:10.407 that even an entomologist cannot identify them under a microscope. NOTE Paragraph 00:11:11.096 --> 00:11:12.881 But they have an Achilles' heel. 00:11:12.905 --> 00:11:16.105 This is what mosquitoes flirting with each other looks like. 00:11:16.129 --> 00:11:18.358 That's a male chasing a female. 00:11:18.382 --> 00:11:22.203 They're actually talking to each other with their wingbeat frequencies. 00:11:22.227 --> 00:11:23.267 (Buzzing sound) 00:11:23.291 --> 00:11:25.648 And thus, they have a signature. 00:11:26.652 --> 00:11:30.016 We realized that using a regular phone, 00:11:30.040 --> 00:11:32.581 a $5-10 flip phone -- 00:11:32.605 --> 00:11:34.707 how many remember what this object is? NOTE Paragraph 00:11:34.731 --> 00:11:35.791 (Laughter) NOTE Paragraph 00:11:35.815 --> 00:11:39.976 We can record these acoustic signatures from mosquitoes. 00:11:40.000 --> 00:11:41.936 I'll tell you exactly how to do this. NOTE Paragraph 00:11:41.960 --> 00:11:43.651 I caught some mosquitoes outside. 00:11:43.675 --> 00:11:46.063 Unlike Bill [Gates], I'm not going to release them. NOTE Paragraph 00:11:46.087 --> 00:11:47.127 (Laughter) NOTE Paragraph 00:11:47.151 --> 00:11:49.726 But I will tell you how to record from this. 00:11:49.750 --> 00:11:52.192 All you do is tap them and they fly. 00:11:52.216 --> 00:11:53.557 You can first test -- 00:11:53.581 --> 00:11:55.333 I can actually hear that. 00:11:55.357 --> 00:11:57.811 And you bring your phone, which has microphones -- 00:11:57.835 --> 00:12:00.201 it turns out the mics are so damn good already, 00:12:00.225 --> 00:12:01.465 even on regular phones, 00:12:01.489 --> 00:12:03.922 that you can pick up this near-field signature. 00:12:03.946 --> 00:12:06.084 And since I'm out of time, 00:12:06.108 --> 00:12:09.800 let me just play the recording that I made a day ago. NOTE Paragraph 00:12:09.824 --> 00:12:12.364 (Mosquitoes buzz) NOTE Paragraph 00:12:12.388 --> 00:12:15.316 This is all the charming sound that you heard before 00:12:15.340 --> 00:12:16.524 that you all love. 00:12:18.786 --> 00:12:20.207 One of the contexts of this 00:12:20.231 --> 00:12:23.445 is that being able to do this with a regular cell phone 00:12:23.469 --> 00:12:26.629 allows us to map mosquito species. 00:12:27.657 --> 00:12:29.349 Using a flip phone, 00:12:29.373 --> 00:12:32.351 we mapped one of the largest acoustic databases 00:12:32.375 --> 00:12:37.603 with 25 to 20 species of mosquitoes that carry human pathogens. 00:12:37.627 --> 00:12:39.306 And from this and machine learning, 00:12:39.330 --> 00:12:41.114 anybody who uploads this data, 00:12:41.138 --> 00:12:43.126 we can identify and tell the probability 00:12:43.150 --> 00:12:45.984 of what species of mosquitoes you're actually working with. 00:12:46.008 --> 00:12:48.823 We call this Abuzz, and if any of you want to sign up, 00:12:48.847 --> 00:12:50.065 just go to the website. NOTE Paragraph 00:12:50.523 --> 00:12:52.165 Let me close with something 00:12:52.189 --> 00:12:54.490 that's very important and dear to my heart. 00:12:55.504 --> 00:12:59.451 One of the challenges of today is we have terrible problems. 00:12:59.475 --> 00:13:02.373 We have a billion people with absolutely no health care, 00:13:02.397 --> 00:13:04.522 climate change, biodiversity loss, 00:13:04.546 --> 00:13:05.731 on and on and on. 00:13:06.226 --> 00:13:09.176 And we hope that science is going to provide the answer. NOTE Paragraph 00:13:09.590 --> 00:13:11.738 But before you leave this theatre today, 00:13:11.762 --> 00:13:13.516 I want you to promise one thing. 00:13:13.925 --> 00:13:16.303 We're going to make science accessible -- 00:13:17.066 --> 00:13:19.205 not just to the people who can afford it, 00:13:19.229 --> 00:13:21.111 but a billion others who can't. 00:13:21.761 --> 00:13:25.777 Let's make science and scientific literacy a human right. 00:13:27.564 --> 00:13:32.239 The moment that you pass the tingling feeling of making a discovery 00:13:32.263 --> 00:13:33.774 to another child, 00:13:34.443 --> 00:13:38.235 you're enabling them to be the next group of people 00:13:38.259 --> 00:13:40.367 who will actually solve these problems. NOTE Paragraph 00:13:40.391 --> 00:13:41.566 Thank you. NOTE Paragraph 00:13:41.590 --> 00:13:44.968 (Applause)