with robots, for better or for worse.

They’re either super sweet like Bicentennial Man

and WALL-E or super terrifying like in iRobot or the Terminator.

But what if I told you scientists have been

making robots that you can’t see or hear

as they creep up on human civilization.

That’s right, scientists are working on making very tiny robots.

In the future, these nanobots might be

able to deliver drugs anywhere in the body,

clean up oil spills and do a lot more.

Time to learn about the rise of the molecular machines.

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These incredibly small gadgets are made from molecules that are orders

of magnitude smaller than a human cell.

They move, change form, and -- most importantly

do work on their environment, all thanks

to scientists controlling their chemical and physical properties.

So far, scientists have created molecular motors,

switches, shuttles, turnstiles, and even nanocars.

Let’s start off with the smallest molecular

machine building block: molecular switches.

Here is Dan Claes from the University of Nebraska:

Dan: “Like light switches, molecular switches

go on or off, thanks to molecules undergoing “conformational changes.”

Those are simply changes in structure -- they’ve still

got all the same atoms attached in the same order,

but they can bend or twist in response to a stimulus, sort of like a beach chair

that you can fold and unfold.

By shining UV light, changing temperature, or

prompting chemical reactions in other ways,

scientists can force these molecular switches to undergo conformational changes

and thus switch on or off.”

Switches are so basic, though.

These molecular machines can get way more complex.

They can be 3-D, they can be DNA-based, they can walk, I could go on.

So scientists are working toward building molecular

machines built from many tiny robots working

together toward collective motion..

So, in theory, nanoscale machines could

move things at a macro level.

Not macro like helping you move your TV.

But macro like proteins and cells.

Why does that matter?

Dan: “Well, think about how our muscles work.

When you contract your muscles, whether to lift

something heavy, like your TV, or just put on a gun

show, your muscle isn’t working as one big machine.

It’s millions of tiny muscle cells, and inside

those muscle cells, even tinier sarcomeres that

make your muscle fibers contract and extend.

Sound familiar?

There have been some attempts to make nanobots

to work as artificial muscles.

These are light-activated nanosheets sliding in

a motion similar to natural muscle fibers.

Much like real muscles, these tiny machines’

movement cause a much larger movement,

relative to their own size.”

So in the future, this means we could potentially

implant artificial muscles into our bodies.

Another cool application would be transporting

nanocargo such as drugs or even information

around our bodies and in the environment.

These single-molecule-sized nanocars and

nanotrucks have spherical wheels, rotating axles,

and a molecular chassis and can be powered by

shining light or using other chemistry tricks.

On a larger scale, microrockets and microsubmarines

can also move around and deliver larger cargo.

For example, microsubmarines could be

unleashed in order to capture and remove

oil in the event of massive oil spills.

Both of these micromachines work by reacting with surrounding solutions to form gas bubbles

that propel the microvehicles around.

And they pick up and drop off cargo also using

chemistry -- they can pick up oil in water

through hydrophobic interactions or could

pick up magnetized cargo by adjusting surrounding magnetic fields.

Dan: “All of this sounds great.

But there are still plenty of examples of other

technologies that beat out molecular machines

on efficiency, speed, and capabilities.

These miniature workhorses use much less

energy compared with bigger machines,

but scientists still have to figure out how to take

advantage of that before nanobots can work for us.

We can eventually take this nanoscale

motion and create macroscale results.

But you’ll still have to ask your friends to help you move.

Sorry.”

What’s your favorite robot?

We’ll accept full-size robots.

R2D2? Optimus Prime? Bender?

Let us know in the comments.

For more small science, check out our episode

on what an atom actually looks like.

Or find out what’s inside your iPhone without breaking it open.

And subscribe for more weekly chemistry videos.

Thanks for watching.