Lifesaving scientific tools made of paper | Manu Prakash

So, I love making tools and sharing them with people.

I remember as a child,

my first tool I built was actually a microscope

that I built by stealing lenses from my brother's eyeglasses.

He wasn't that thrilled.

But, you know, maybe because of that moment,

30 years later,

I'm still making microscopes.

And the reason I built these tools is for moments like this.

(Video) Girl: I have black things in my hair --

Manu Prakash: This is a school in the Bay Area.

(Video) MP: The living world far supersedes our imagination

of how things actually work.

(Video) Boy: Oh my God!

MP: Right -- oh my God!

I hadn't realized this would be such a universal phrase.

Over the last two years,

in my lab,

we built 50,000 Foldscopes

and shipped them to 130 countries in the world,

at no cost to the kids we sent them to.

This year alone,

with the support of our community,

we are planning to ship a million microscopes

to kids around the world.

What does that do?

It creates an inspiring community of people around the world,

learning and teaching each other,

from Kenya to Kampala to Kathmandu to Kansas.

And one of the phenomenal things that I love about this

is the sense of community.

There's a kid in Nicaragua

teaching others how to identify mosquito species that carry dengue

by looking at the larva under a microscope.

There's a pharmacologist who came up with a new way

to detect fake drugs anywhere.

There is a girl who wondered:

"How does glitter actually work?"

and discovered the physics of crystalline formation in glitter.

There is an Argentinian doctor

who's trying to do field cervical cancer screening with this tool.

And yours very truly found a species of flea

that was dug inside my heel in my foot one centimeter deep.

Now, you might think of these as anomalies.

But there is a method to this madness.

I call this "frugal science" --

the idea of sharing the experience of science,

and not just the information.

To remind you:

there are a billion people on this planet

who live with absolutely no infrastructure:

no roads,

no electricity

and thus, no health care.

Also, there a billion kids on this planet that live in poverty.

How are we supposed to inspire them

for the next generation of solution makers?

There are health care workers that we put on the line

to fight infectious diseases,

to protect us with absolutely bare-minimum tools and resources.

So as a lab at Stanford,

I think of this from a context of frugal science

and building solutions for these communities.

Often we think about being able to do diagnosis under a tree, off-grid.

I'll tell you two examples today of new tools.

One of them starts in Uganda.

In 2013,

on a field trip to detect schistosomiasis with Foldscopes,

I made a minor observation.

In a clinic,

in a far, remote area,

I saw a centrifuge being used as a doorstop.

I mean -- quite literally, the doorstop.

And I asked them and they said,

"Oh, we don't actually have electricity,

so this piece of junk is good as a doorstop."

Centrifuges, for some of you who don't know,

are the pinnacle tool to be able to do sample processing.

You separate components of blood or body fluids

to be able to detect and identify pathogens.

But centrifuges are bulky, expensive --

cost around 1,000 dollars --

and really hard to carry out in the field.

And of course,

they don't work without power.

Sound familiar?

So we started thinking about solving this problem,

and I came back --

kept thinking about toys.

Now ...

I have a few with me here.

I first started with yo-yos ...

and I'm a terrible yo-yo thrower.

Because these objects spin,

we wondered,

could we actually use the physics of these objects

to be able to build centrifuges?

This was possibly the worst throw I could make.

But you might start realizing,

if you start exploring the space of toys --

we tried these spinning tops,

and then in the lab,

we stumbled upon this wonder.

It's the whirligig, or a buzzer, or a rundle.

A couple of strings and a little disk,

and if I push, it spins.

How many of you have played with this as a kid?

This is called a button-on-a-string.

OK, maybe 50 percent of you.

What you didn't realize --

that this little object

is the oldest toy in the history of mankind ...

5,000 years ago.

We have found relics of this object hidden around on our planet.

Now the irony is,

we actually don't understand how this little thing works.

That's when I get excited.

So we got back to work,

wrote down a couple of equations.

If you take the input torque that you put in,

you take the drag on this disc,

and the twist drag on these strings,

you should be able to mathematically solve this.

This is not the only equation in my talk.

Ten pages of math later,

we could actually write down the complete analytical solution

for this dynamic system.

And out comes what we call "Paperfuge."

That's my postdoc Saad Bhamla,

who's the co-inventor of Paperfuge.

And to the left, you see all the centrifuges

that we're trying to replace.

This little object that you see right here

is a disc, a couple of strings and a handle.

And when I spin

and I push,

it starts to spin.

Now, when you realize,

when you do the math,

when we calculate the rpm for this object,

mathematically, we should be able to go all the way to a million rpm.

Now, there is a little twist in human anatomy,

because the resonant frequency of this object is about 10 hertz,

and if you've ever played the piano,

you can't go higher than two or three hertz.

The maximum speed we've been able to achieve with this object

is not 10,000 rpm,

not 50,000 rpm --

120,000 rpm.

That's equal to 30,000 g-forces.

If I was to stick you right here and have it spin,

you would think about the types of forces you would experience.

One of the factors of a tool like this

is to be able to do diagnosis with this.

So, I'm going to do a quick demo here, where --

this is a moment where I'm going to make a little finger prick,

and a tiny drop of blood is going to come out.

If you don't like blood, you don't have to look at it.

Here is a little lancet.

These lancets are available everywhere,

completely passive.

And if I've had breakfast today ...

That didn't hurt at all.

OK, I take a little capillary with a drop of blood --

now this drop of blood has answers,

that's why I'm interested in it.

It might actually tell me whether I have malaria right now or not.

I take a little capillary,

and you see it starts wicking in.

I'm going to draw a little more blood.

And that's good enough for right now.

Now, I just seal this capillary by putting it in clay.

And now that's sealed the sample.

We're going to take the sample,

mount it on Paperfuge.

A little piece of tape to make a sealed cavity.

So now the sample is completely enclosed.

And we are ready for a spin.

I'm pushing and pulling with this object.

I'm going to load this up ...

And you see the object starts spinning.

Unlike a regular centrifuge,

this is a counter-rotating centrifuge.

It goes back and forth, back and forth ...

And now I'm charging it up,

and you see it builds momentum.

And now -- I don't know if you can hear this --

30 seconds of this,

and I should be able to separate all the blood cells with the plasma.

And the ratio of those blood cells to plasma --

(Applause)

Already, if you see right here,

if you focus on this,

you should be able to see a separated volume

of blood and plasma.

And the ratio of that actually tells me whether I might be anemic.

One of the aspects of this is, we build many types of Paperfuges.

This one allows us to identify malaria parasites

by running them for a little longer,

and we can identify malaria parasites that are in the blood

that we can separate out and detect with something like a centrifuge.

Another version of this allows me to separate nucleic acids

to be able to do nucleic acid tests out in the field itself.

Here is another version that allows me to separate bulk samples,

and then, finally,

something new that we've been working on

to be able to implement the entire multiplex test on an object like this.

So where you do the sample preparation and the chemistry in the same object.

Now ...

this is all good,

but when you start thinking about this,

you have to share these tools with people.

And one of the things we did is -- we just got back from Madagascar;

this is what clinical trials for malaria look like --

(Laughter)

You can do this while having coffee.

But most importantly,

this is a village six hours from any road.

We are in a room with one of the senior members of the community

and a health care worker.

It really is this portion of the work that excites me the most --

that smile,

to be able to share simple but powerful tools with people around the world.

Now, I forgot to tell you this,

that all of that cost me 20 cents to make.

OK, in the negative time I have left,

I'll tell you about the most recent --

(Laughter)

invention from our lab.

It's called Abuzz --

the idea that all of you could help us fight mosquitoes;

you could all help us track our enemies.

These are enemies because they cause malaria, Zika, chikungunya, dengue.

But the challenge is that we actually don't know where our enemies are.

The world map for where mosquitoes are is missing.

So we started thinking about this.

There are 3,500 species of mosquitoes,

and they're all very similar.

Some of them are so identical

that even an entomologist cannot identify them under a microscope.

But they have an Achilles' heel.

This is what mosquitoes flirting with each other looks like.

That's a male chasing a female.

They're actually talking to each other with their wingbeat frequencies.

(Buzzing sound)

And thus, they have a signature.

We realized that using a regular phone,

a $5-10 flip phone --

how many remember what this object is?

(Laughter)

We can record these acoustic signatures from mosquitoes.

I'll tell you exactly how to do this.

I caught some mosquitoes outside.

Unlike Bill [Gates], I'm not going to release them.

(Laughter)

But I will tell you how to record from this.

All you do is tap them and they fly.

You can first test --

I can actually hear that.

And you bring your phone, which has microphones --

it turns out the mics are so damn good already,

even on regular phones,

that you can pick up this near-field signature.

And since I'm out of time,

let me just play the recording that I made a day ago.

(Mosquitoes buzz)

This is all the charming sound that you heard before

that you all love.

One of the contexts of this

is that being able to do this with a regular cell phone

allows us to map mosquito species.

Using a flip phone,

we mapped one of the largest acoustic databases

with 25 to 20 species of mosquitoes that carry human pathogens.

And from this and machine learning,

anybody who uploads this data,

we can identify and tell the probability

of what species of mosquitoes you're actually working with.

We call this Abuzz, and if any of you want to sign up,

just go to the website.

Let me close with something

that's very important and dear to my heart.

One of the challenges of today is we have terrible problems.

We have a billion people with absolutely no health care,

climate change, biodiversity loss,

on and on and on.

And we hope that science is going to provide the answer.

But before you leave this theatre today,

I want you to promise one thing.

We're going to make science accessible --

not just to the people who can afford it,

but a billion others who can't.

Let's make science and scientific literacy a human right.

The moment that you pass the tingling feeling of making a discovery

to another child,

you're enabling them to be the next group of people

who will actually solve these problems.

Thank you.

(Applause)