0:00:01.150,0:00:04.285
So, I love making tools[br]and sharing them with people.

0:00:05.118,0:00:06.508
I remember as a child,

0:00:06.532,0:00:09.825
my first tool I built[br]was actually a microscope

0:00:09.849,0:00:13.521
that I built by stealing lenses[br]from my brother's eyeglasses.

0:00:14.289,0:00:16.076
He wasn't that thrilled.

0:00:16.100,0:00:18.270
But, you know, maybe[br]because of that moment,

0:00:18.294,0:00:19.447
30 years later,

0:00:19.471,0:00:21.359
I'm still making microscopes.

0:00:22.359,0:00:25.658
And the reason I built these tools[br]is for moments like this.

0:00:27.559,0:00:29.979
(Video) Girl: I have[br]black things in my hair --

0:00:30.003,0:00:32.278
Manu Prakash: This is a school[br]in the Bay Area.

0:00:32.840,0:00:37.304
(Video) MP: The living world[br]far supersedes our imagination

0:00:37.328,0:00:39.295
of how things actually work.

0:00:39.319,0:00:41.770
(Video) Boy: Oh my God!

0:00:43.773,0:00:46.125
MP: Right -- oh my God!

0:00:46.621,0:00:49.622
I hadn't realized this would be[br]such a universal phrase.

0:00:51.123,0:00:52.923
Over the last two years,

0:00:52.947,0:00:54.114
in my lab,

0:00:54.138,0:00:56.213
we built 50,000 Foldscopes

0:00:56.237,0:00:59.147
and shipped them[br]to 130 countries in the world,

0:00:59.171,0:01:01.757
at no cost to the kids we sent them to.

0:01:02.238,0:01:03.481
This year alone,

0:01:03.505,0:01:05.637
with the support of our community,

0:01:05.661,0:01:08.141
we are planning to ship[br]a million microscopes

0:01:08.165,0:01:09.527
to kids around the world.

0:01:10.034,0:01:11.604
What does that do?

0:01:11.628,0:01:15.384
It creates an inspiring community[br]of people around the world,

0:01:15.408,0:01:17.080
learning and teaching each other,

0:01:17.104,0:01:21.194
from Kenya to Kampala[br]to Kathmandu to Kansas.

0:01:21.218,0:01:23.863
And one of the phenomenal things[br]that I love about this

0:01:23.887,0:01:25.443
is the sense of community.

0:01:25.871,0:01:27.263
There's a kid in Nicaragua

0:01:27.287,0:01:31.481
teaching others how to identify[br]mosquito species that carry dengue

0:01:31.505,0:01:33.923
by looking at the larva[br]under a microscope.

0:01:33.947,0:01:36.495
There's a pharmacologist[br]who came up with a new way

0:01:36.519,0:01:38.762
to detect fake drugs anywhere.

0:01:39.402,0:01:41.461
There is a girl who wondered:

0:01:41.485,0:01:43.183
"How does glitter actually work?"

0:01:43.207,0:01:46.926
and discovered the physics[br]of crystalline formation in glitter.

0:01:47.713,0:01:49.318
There is an Argentinian doctor

0:01:49.342,0:01:53.604
who's trying to do field cervical cancer[br]screening with this tool.

0:01:53.628,0:01:57.366
And yours very truly found[br]a species of flea

0:01:57.390,0:02:02.166
that was dug inside my heel in my foot[br]one centimeter deep.

0:02:03.321,0:02:07.578
Now, you might think[br]of these as anomalies.

0:02:07.975,0:02:09.995
But there is a method to this madness.

0:02:10.617,0:02:12.847
I call this "frugal science" --

0:02:12.871,0:02:16.723
the idea of sharing[br]the experience of science,

0:02:16.747,0:02:18.462
and not just the information.

0:02:19.011,0:02:20.226
To remind you:

0:02:20.250,0:02:22.334
there are a billion people on this planet

0:02:22.358,0:02:24.873
who live with absolutely[br]no infrastructure:

0:02:24.897,0:02:26.511
no roads,

0:02:26.535,0:02:27.917
no electricity

0:02:27.941,0:02:29.727
and thus, no health care.

0:02:30.967,0:02:35.203
Also, there a billion kids[br]on this planet that live in poverty.

0:02:35.700,0:02:37.368
How are we supposed to inspire them

0:02:37.392,0:02:39.714
for the next generation[br]of solution makers?

0:02:40.264,0:02:43.012
There are health care workers[br]that we put on the line

0:02:43.036,0:02:44.954
to fight infectious diseases,

0:02:44.978,0:02:49.435
to protect us with absolutely[br]bare-minimum tools and resources.

0:02:50.584,0:02:52.178
So as a lab at Stanford,

0:02:52.202,0:02:56.139
I think of this from a context[br]of frugal science

0:02:56.163,0:02:58.748
and building solutions[br]for these communities.

0:02:58.772,0:03:03.354
Often we think about being able to do[br]diagnosis under a tree, off-grid.

0:03:03.816,0:03:06.545
I'll tell you two examples[br]today of new tools.

0:03:06.569,0:03:08.374
One of them starts in Uganda.

0:03:08.751,0:03:10.280
In 2013,

0:03:10.304,0:03:14.350
on a field trip to detect[br]schistosomiasis with Foldscopes,

0:03:14.374,0:03:16.932
I made a minor observation.

0:03:16.956,0:03:18.533
In a clinic,

0:03:18.557,0:03:19.896
in a far, remote area,

0:03:19.920,0:03:23.508
I saw a centrifuge[br]being used as a doorstop.

0:03:24.192,0:03:26.583
I mean -- quite literally, the doorstop.

0:03:26.607,0:03:28.333
And I asked them and they said,

0:03:28.357,0:03:30.384
"Oh, we don't actually have electricity,

0:03:30.408,0:03:33.937
so this piece of junk[br]is good as a doorstop."

0:03:34.624,0:03:37.326
Centrifuges, for some of you[br]who don't know,

0:03:37.350,0:03:40.574
are the pinnacle tool to be able[br]to do sample processing.

0:03:40.598,0:03:43.340
You separate components[br]of blood or body fluids

0:03:43.364,0:03:45.824
to be able to detect[br]and identify pathogens.

0:03:46.419,0:03:49.253
But centrifuges are bulky, expensive --

0:03:49.277,0:03:51.471
cost around 1,000 dollars --

0:03:51.495,0:03:53.501
and really hard to carry out in the field.

0:03:53.525,0:03:54.682
And of course,

0:03:54.706,0:03:56.140
they don't work without power.

0:03:56.164,0:03:57.556
Sound familiar?

0:03:57.580,0:04:00.128
So we started thinking[br]about solving this problem,

0:04:00.152,0:04:01.702
and I came back --

0:04:01.726,0:04:03.392
kept thinking about toys.

0:04:03.818,0:04:04.982
Now ...

0:04:06.030,0:04:07.788
I have a few with me here.

0:04:07.812,0:04:09.919
I first started with yo-yos ...

0:04:09.943,0:04:12.574
and I'm a terrible yo-yo thrower.

0:04:12.923,0:04:14.604
Because these objects spin,

0:04:14.628,0:04:15.790
we wondered,

0:04:15.814,0:04:18.171
could we actually use[br]the physics of these objects

0:04:18.195,0:04:19.904
to be able to build centrifuges?

0:04:21.257,0:04:23.747
This was possibly the worst[br]throw I could make.

0:04:24.436,0:04:25.929
But you might start realizing,

0:04:25.953,0:04:28.792
if you start exploring[br]the safe space of toys --

0:04:28.816,0:04:31.421
we tried these spinning tops,

0:04:31.445,0:04:33.327
and then in the lab,

0:04:33.351,0:04:35.433
we stumbled upon this wonder.

0:04:35.770,0:04:39.256
It's the whirligig,[br]or a buzzer, or a rundle.

0:04:39.280,0:04:41.697
A couple of strings and a little disk,

0:04:41.721,0:04:43.928
and if I push, it spins.

0:04:44.350,0:04:46.694
How many of you have played[br]with this as a kid?

0:04:46.718,0:04:48.566
This is called a button-on-a-string.

0:04:48.590,0:04:50.226
OK, maybe 50 percent of you.

0:04:50.250,0:04:51.808
What you didn't realize --

0:04:51.832,0:04:54.145
that this little object

0:04:54.169,0:04:58.532
is the oldest toy[br]in the history of mankind ...

0:04:59.007,0:05:00.652
5,000 years ago.

0:05:00.676,0:05:04.375
We have found relics of this object[br]hidden around on our planet.

0:05:05.104,0:05:07.045
Now the irony is,

0:05:07.069,0:05:10.804
we actually don't understand[br]how this little thing works.

0:05:10.828,0:05:12.231
That's when I get excited.

0:05:12.797,0:05:14.878
So we got back to work,

0:05:14.902,0:05:16.692
wrote down a couple of equations.

0:05:17.056,0:05:20.369
If you take the input torque[br]that you put in,

0:05:20.393,0:05:22.497
you take the drag on this disc,

0:05:22.521,0:05:24.426
and the twist drag on these strings,

0:05:24.450,0:05:26.939
you should be able[br]to mathematically solve this.

0:05:26.963,0:05:29.771
This is not the only equation in my talk.

0:05:29.795,0:05:31.627
Ten pages of math later,

0:05:31.651,0:05:34.510
we could actually write down[br]the complete analytical solution

0:05:34.534,0:05:35.808
for this dynamic system.

0:05:36.388,0:05:39.999
And out comes what we call "Paperfuge."

0:05:40.023,0:05:42.567
That's my postdoc Saad Bhamla,

0:05:42.591,0:05:44.258
who's the co-inventor of Paperfuge.

0:05:44.282,0:05:46.527
And to the left, you see[br]all the centrifuges

0:05:46.551,0:05:47.978
that we're trying to replace.

0:05:48.002,0:05:51.709
This little object that you see right here

0:05:52.939,0:05:56.184
is a disc, a couple[br]of strings and a handle.

0:05:56.208,0:05:57.382
And when I spin

0:05:57.940,0:05:59.093
and I push,

0:05:59.117,0:06:00.269
it starts to spin.

0:06:00.293,0:06:02.378
Now, when you realize,

0:06:02.950,0:06:04.345
when you do the math,

0:06:05.579,0:06:08.069
when we calculate the rpm for this object,

0:06:08.093,0:06:12.825
mathematically, we should be able[br]to go all the way to a million rpm.

0:06:12.849,0:06:15.042
Now, there is a little twist[br]in human anatomy,

0:06:15.066,0:06:18.141
because the resonant frequency[br]of this object is about 10 hertz,

0:06:18.165,0:06:19.969
and if you've ever played the piano,

0:06:19.993,0:06:22.087
you can't go higher[br]than two or three hertz.

0:06:22.111,0:06:25.375
The maximum speed we've been able[br]to achieve with this object

0:06:25.399,0:06:27.328
is not 10,000 rpm,

0:06:27.352,0:06:28.956
not 50,000 rpm --

0:06:28.980,0:06:30.905
120,000 rpm.

0:06:30.929,0:06:33.733
That's equal to 30,000 g-forces.

0:06:33.757,0:06:36.964
If I was to stick you right here[br]and have it spin,

0:06:36.988,0:06:40.417
you would think about the types[br]of forces you would experience.

0:06:40.441,0:06:42.679
One of the factors of a tool like this

0:06:42.703,0:06:45.697
is to be able to do diagnosis with this.

0:06:45.721,0:06:50.001
So, I'm going to do[br]a quick demo here, where --

0:06:50.442,0:06:54.037
this is a moment where I'm going[br]to make a little finger prick,

0:06:54.061,0:06:56.336
and a tiny drop of blood[br]is going to come out.

0:06:56.360,0:06:58.981
If you don't like blood,[br]you don't have to look at it.

0:06:59.005,0:07:00.344
Here is a little lancet.

0:07:00.368,0:07:02.238
These lancets are available everywhere,

0:07:02.262,0:07:03.785
completely passive.

0:07:03.809,0:07:07.395
And if I've had breakfast today ...

0:07:10.047,0:07:11.534
That didn't hurt at all.

0:07:11.558,0:07:15.542
OK, I take a little capillary[br]with a drop of blood --

0:07:15.566,0:07:17.825
now this drop of blood has answers,

0:07:17.849,0:07:19.528
that's why I'm interested in it.

0:07:19.910,0:07:23.377
It might actually tell me whether[br]I have malaria right now or not.

0:07:23.401,0:07:25.233
I take a little capillary,

0:07:25.257,0:07:27.382
and you see it starts wicking in.

0:07:27.888,0:07:30.156
I'm going to draw a little more blood.

0:07:32.782,0:07:35.025
And that's good enough for right now.

0:07:35.519,0:07:39.649
Now, I just seal this capillary[br]by putting it in clay.

0:07:43.492,0:07:45.772
And now that's sealed the sample.

0:07:45.796,0:07:47.925
We're going to take the sample,

0:07:47.949,0:07:49.913
mount it on Paperfuge.

0:07:57.092,0:08:00.480
A little piece of tape[br]to make a sealed cavity.

0:08:00.975,0:08:03.870
So now the sample is completely enclosed.

0:08:07.107,0:08:09.400
And we are ready for a spin.

0:08:11.019,0:08:13.060
I'm pushing and pulling with this object.

0:08:13.084,0:08:14.783
I'm going to load this up ...

0:08:16.277,0:08:18.560
And you see the object starts spinning.

0:08:18.584,0:08:20.598
Unlike a regular centrifuge,

0:08:20.622,0:08:24.401
this is a counter-rotating centrifuge.

0:08:24.425,0:08:26.761
It goes back and forth, back and forth ...

0:08:27.221,0:08:29.349
And now I'm charging it up,

0:08:29.373,0:08:31.201
and you see it builds momentum.

0:08:32.185,0:08:34.797
And now -- I don't know[br]if you can hear this --

0:08:34.821,0:08:36.360
30 seconds of this,

0:08:36.989,0:08:41.314
and I should be able to separate[br]all the blood cells with the plasma.

0:08:41.938,0:08:44.751
And the ratio of those blood [br]cells to plasma --

0:08:44.775,0:08:46.789
(Applause)

0:08:48.439,0:08:50.774
Already, if you see right here,

0:08:52.206,0:08:53.830
if you focus on this,

0:08:53.854,0:08:56.399
you should be able to see[br]a separated volume

0:08:57.272,0:08:59.130
of blood and plasma.

0:08:59.154,0:09:03.077
And the ratio of that actually tells me[br]whether I might be anemic.

0:09:03.101,0:09:07.138
One the of aspects of this is,[br]we build many types of Paperfuges.

0:09:07.162,0:09:11.628
This one allows us to identify[br]malaria parasites

0:09:11.652,0:09:13.469
by running them for a little longer,

0:09:13.493,0:09:17.059
and we can identify malaria parasites[br]that are in the blood

0:09:17.083,0:09:20.657
that we can separate out and detect[br]with something like a centrifuge.

0:09:20.681,0:09:25.161
Another version of this allows me[br]to separate nucleic acids

0:09:25.185,0:09:28.742
to be able to do nucleic acid tests[br]out in the field itself.

0:09:29.573,0:09:33.917
Here is another version that allows me[br]to separate bulk samples,

0:09:33.941,0:09:35.511
and then, finally,

0:09:35.535,0:09:37.535
something new that we've been working on

0:09:37.559,0:09:42.354
to be able to implement the entire[br]multiplex test on an object like this.

0:09:42.378,0:09:46.715
So where you do the sample preparation[br]and the chemistry in the same object.

0:09:47.540,0:09:48.826
Now ...

0:09:48.850,0:09:50.120
this is all good,

0:09:50.144,0:09:52.051
but when you start thinking about this,

0:09:52.075,0:09:54.164
you have to share these tools with people.

0:09:54.188,0:09:57.570
And one of the things we did is --[br]we just got back from Madagascar;

0:09:57.594,0:10:00.172
this is what clinical trials[br]for malaria look like --

0:10:00.196,0:10:01.199
(Laughter)

0:10:01.223,0:10:03.580
You can do this while having coffee.

0:10:03.604,0:10:05.477
But most importantly,

0:10:05.501,0:10:09.563
this is a village six hours from any road.

0:10:10.036,0:10:14.599
We are in a room with one of the senior[br]members of the community

0:10:14.623,0:10:16.136
and a health care worker.

0:10:16.160,0:10:19.657
It really is this portion of the work[br]that excites me the most --

0:10:19.681,0:10:20.839
that smile,

0:10:20.863,0:10:24.737
to be able to share simple but powerful[br]tools with people around the world.

0:10:25.479,0:10:27.781
Now, I forgot to tell you this,

0:10:27.805,0:10:30.208
that all of that cost me 20 cents to make.

0:10:31.510,0:10:34.392
OK, in the negative time I have left,

0:10:34.416,0:10:36.482
I'll tell you about the most recent --

0:10:36.506,0:10:37.626
(Laughter)

0:10:37.650,0:10:39.520
invention from our lab.

0:10:39.544,0:10:40.897
It's called Abuzz --

0:10:41.618,0:10:45.752
the idea that all of you[br]could help us fight mosquitoes;

0:10:45.776,0:10:48.043
you could all help us track our enemies.

0:10:48.067,0:10:52.055
These are enemies because they cause[br]malaria, Zika, chikungunya, dengue.

0:10:52.079,0:10:56.863
But the challenge is that we actually[br]don't know where our enemies are.

0:10:56.887,0:10:59.866
The world map for where[br]mosquitoes are is missing.

0:11:00.303,0:11:02.046
So we started thinking about this.

0:11:02.070,0:11:04.105
There are 3,500 species of mosquitoes,

0:11:04.129,0:11:05.532
and they're all very similar.

0:11:05.556,0:11:06.995
Some of them are so identical

0:11:07.019,0:11:10.407
that even an entomologist cannot[br]identify them under a microscope.

0:11:11.096,0:11:12.881
But they have an Achilles' heel.

0:11:12.905,0:11:16.105
This is what mosquitoes flirting[br]with each other looks like.

0:11:16.129,0:11:18.358
That's a male chasing a female.

0:11:18.382,0:11:22.203
They're actually talking to each other[br]with their wingbeat frequencies.

0:11:22.227,0:11:23.267
(Buzzing sound)

0:11:23.291,0:11:25.648
And thus, they have a signature.

0:11:26.652,0:11:30.016
We realized that using a regular phone,

0:11:30.040,0:11:32.581
a $5-10 flip phone --

0:11:32.605,0:11:34.707
how many remember what this object is?

0:11:34.731,0:11:35.791
(Laughter)

0:11:35.815,0:11:39.976
We can record these acoustic[br]signatures from mosquitoes.

0:11:40.000,0:11:41.936
I'll tell you exactly how to do this.

0:11:41.960,0:11:43.651
I caught some mosquitoes outside.

0:11:43.675,0:11:46.063
Unlike Bill [Gates], I'm not[br]going to release them.

0:11:46.087,0:11:47.127
(Laughter)

0:11:47.151,0:11:49.726
But I will tell you how[br]to record from this.

0:11:49.750,0:11:52.192
All you do is tap them and they fly.

0:11:52.216,0:11:53.557
You can first test --

0:11:53.581,0:11:55.333
I can actually hear that.

0:11:55.357,0:11:57.811
And you bring your phone,[br]which has microphones --

0:11:57.835,0:12:00.201
it turns out the mics[br]are so damn good already,

0:12:00.225,0:12:01.465
even on regular phones,

0:12:01.489,0:12:03.922
that you can pick up[br]this near-field signature.

0:12:03.946,0:12:06.084
And since I'm out of time,

0:12:06.108,0:12:09.800
let me just play the recording[br]that I made a day ago.

0:12:09.824,0:12:12.364
(Mosquitoes buzz)

0:12:12.388,0:12:15.316
This is all the charming sound[br]that you heard before

0:12:15.340,0:12:16.524
that you all love.

0:12:18.786,0:12:20.207
One of the contexts of this

0:12:20.231,0:12:23.445
is that being able to do this[br]with a regular cell phone

0:12:23.469,0:12:26.629
allows us to map mosquito species.

0:12:27.657,0:12:29.349
Using a flip phone,

0:12:29.373,0:12:32.351
we mapped one of the largest[br]acoustic databases

0:12:32.375,0:12:37.603
with 25 to 20 species of mosquitoes[br]that carry human pathogens.

0:12:37.627,0:12:39.306
And from this and machine learning,

0:12:39.330,0:12:41.114
anybody who uploads this data,

0:12:41.138,0:12:43.126
we can identify and tell the probability

0:12:43.150,0:12:45.984
of what species of mosquitoes[br]you're actually working with.

0:12:46.008,0:12:48.823
We call this Abuzz,[br]and if any of you want to sign up,

0:12:48.847,0:12:50.065
just go to the website.

0:12:50.523,0:12:52.165
Let me close with something

0:12:52.189,0:12:54.490
that's very important[br]and dear to my heart.

0:12:55.504,0:12:59.451
One of the challenges of today[br]is we have terrible problems.

0:12:59.475,0:13:02.373
We have a billion people[br]with absolutely no health care,

0:13:02.397,0:13:04.522
climate change, biodiversity loss,

0:13:04.546,0:13:05.731
on and on and on.

0:13:06.226,0:13:09.176
And we hope that science[br]is going to provide the answer.

0:13:09.590,0:13:11.738
But before you leave this theatre today,

0:13:11.762,0:13:13.516
I want you to promise one thing.

0:13:13.925,0:13:16.303
We're going to make science accessible --

0:13:17.066,0:13:19.205
not just to the people who can afford it,

0:13:19.229,0:13:21.111
but a billion others who can't.

0:13:21.761,0:13:25.777
Let's make science and scientific[br]literacy a human right.

0:13:27.564,0:13:32.239
The moment that you pass the tingling[br]feeling of making a discovery

0:13:32.263,0:13:33.774
to another child,

0:13:34.443,0:13:38.235
you're enabling them to be[br]the next group of people

0:13:38.259,0:13:40.367
who will actually solve these problems.

0:13:40.391,0:13:41.566
Thank you.

0:13:41.590,0:13:44.968
(Applause)