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We have spent years dreaming up a future
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with robots, for better or for worse.
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They’re either super sweet like Bicentennial Man
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and WALL-E or super terrifying like in iRobot or the Terminator.
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But what if I told you scientists have been
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making robots that you can’t see or hear
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as they creep up on human civilization.
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That’s right, scientists are working on making very tiny robots.
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In the future, these nanobots might be
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able to deliver drugs anywhere in the body,
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clean up oil spills and do a lot more.
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Time to learn about the rise of the molecular machines.
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[Reactions splash]
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These incredibly small gadgets are made from molecules that are orders
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of magnitude smaller than a human cell.
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They move, change form, and -- most importantly
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do work on their environment, all thanks
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to scientists controlling their chemical and physical properties.
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So far, scientists have created molecular motors,
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switches, shuttles, turnstiles, and even nanocars.
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Let’s start off with the smallest molecular
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machine building block: molecular switches.
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Here is Dan Claes from the University of Nebraska:
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Dan: “Like light switches, molecular switches
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go on or off, thanks to molecules undergoing “conformational changes.”
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Those are simply changes in structure -- they’ve still
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got all the same atoms attached in the same order,
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but they can bend or twist in response to a stimulus, sort of like a beach chair
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that you can fold and unfold.
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By shining UV light, changing temperature, or
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prompting chemical reactions in other ways,
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scientists can force these molecular switches to undergo conformational changes
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and thus switch on or off.”
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Switches are so basic, though.
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These molecular machines can get way more complex.
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They can be 3-D, they can be DNA-based, they can walk, I could go on.
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So scientists are working toward building molecular
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machines built from many tiny robots working
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together toward collective motion..
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So, in theory, nanoscale machines could
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move things at a macro level.
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Not macro like helping you move your TV.
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But macro like proteins and cells.
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Why does that matter?
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Dan: “Well, think about how our muscles work.
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When you contract your muscles, whether to lift
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something heavy, like your TV, or just put on a gun
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show, your muscle isn’t working as one big machine.
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It’s millions of tiny muscle cells, and inside
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those muscle cells, even tinier sarcomeres that
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make your muscle fibers contract and extend.
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Sound familiar?
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There have been some attempts to make nanobots
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to work as artificial muscles.
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These are light-activated nanosheets sliding in
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a motion similar to natural muscle fibers.
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Much like real muscles, these tiny machines’
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movement cause a much larger movement,
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relative to their own size.”
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So in the future, this means we could potentially
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implant artificial muscles into our bodies.
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Another cool application would be transporting
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nanocargo such as drugs or even information
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around our bodies and in the environment.
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These single-molecule-sized nanocars and
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nanotrucks have spherical wheels, rotating axles,
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and a molecular chassis and can be powered by
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shining light or using other chemistry tricks.
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On a larger scale, microrockets and microsubmarines
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can also move around and deliver larger cargo.
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For example, microsubmarines could be
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unleashed in order to capture and remove
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oil in the event of massive oil spills.
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Both of these micromachines work by reacting with surrounding solutions to form gas bubbles
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that propel the microvehicles around.
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And they pick up and drop off cargo also using
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chemistry -- they can pick up oil in water
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through hydrophobic interactions or could
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pick up magnetized cargo by adjusting surrounding magnetic fields.
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Dan: “All of this sounds great.
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But there are still plenty of examples of other
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technologies that beat out molecular machines
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on efficiency, speed, and capabilities.
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These miniature workhorses use much less
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energy compared with bigger machines,
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but scientists still have to figure out how to take
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advantage of that before nanobots can work for us.
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We can eventually take this nanoscale
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motion and create macroscale results.
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But you’ll still have to ask your friends to help you move.
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Sorry.”
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What’s your favorite robot?
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We’ll accept full-size robots.
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R2D2? Optimus Prime? Bender?
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Let us know in the comments.
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For more small science, check out our episode
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on what an atom actually looks like.
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Or find out what’s inside your iPhone without breaking it open.
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And subscribe for more weekly chemistry videos.
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Thanks for watching.
