We have spent years dreaming up a future
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.