Autonomously Moving Colloidal Objects that Resemble Living Matter

By Sean Carroll | November 18, 2010 8:01 am

That’s the name of a new paper by Akihisa Shioi, Takahiko Ban, and Youichi Morimune. Abstract:

The design of autonomously moving objects that resemble living matter is an excellent research topic that may develop into various applications of functional motion. Autonomous motion can demonstrate numerous significant characteristics such as transduction of chemical potential into work without heat, chemosensitive motion, chemotactic and phototactic motions, and pulse-like motion with periodicities responding to the chemical environment. Sustainable motion can be realized with an open system that exchanges heat and matter across its interface. Hence the autonomously moving object has a colloidal scale with a large specific area. This article reviews several examples of systems with such characteristics that have been studied, focusing on chemical systems containing amphiphilic molecules.

The journal is called Entropy, which I love. The paper discusses a variety of different systems that can travel, wiggle around, and respond to stimuli in ways that resemble living organisms. Not exactly building life in a test tube, but the boundary grows increasingly blurry.

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  • Ryan

    What a coincidence! Just the other day I was lying on a hillside and commenting on how clouds are, like, totally alive.

    Where do I publish?

  • Johann

    @Ryan: Only if you can use words like chemotaxis, haptotaxis, and colloidal in a sentence and make other people think that you know what you are talking about.

  • Al Feersum

    …a variety of different systems that can travel, wiggle around, and respond to stimuli…

    So… these things are alive then?

    …in ways that resemble living organisms.

    So, in what ways do they not resemble living organisms?

    Not exactly building life in a test tube, but the boundary grows increasingly blurry.

    I’d say!

  • Jack

    I just don’t get it. What a lame blog topic that should have been left on the cutting room floor. There is no science here. Evidently cited just to provide an opportunity to express a personal belief. Why not blog on the news of the day..the successfully trapping the first “anti-atom” and its potential implications? This is real news, real science and in keeping with your expertise. You could teach me something. Instead you give me this?

  • Mike

    Whoa Jack — get up on the wrong side this morning did you? :)

  • Guillermo

    Quick! Someone send Jack a refund.

    Oh, wait….

  • SteveB

    I agree this is an excellent research topic. While I think the word “nanotechnology” is over used, here it fits. More research is going into how the very small can be constructed, used, and made reliable. Do any of you remember the miniscule gears that were made in the very early days of nanotechnology? They failed almost as soon as they were moved since the rules of friction, lubrication, and mechanics are so different at this scale. Working in a world where surface tension and viscosity dominate is so different from our everyday experience and this research can shed light on it. It will feed back to biology as these substances are more easily controlled in shape and substance than biological entities.

    (Imagining what it would be like traveling at a relative 0.9c velocity to something or being in a highly curved spacetime near a black hole requires a big change in perspective, too.)

  • Matt B.

    I saw a show several months ago about this guy that builds wind-powered “animals”. They’re mostly made out of tubes, but they react to wind and water (he places them on seashores), they locomote and they’re taller than a person. The idea in this paper sounds similar, but with the “resembling organic matter” bit thrown in to blur the line more.

  • uhmmm

    Life likes to roll down gradients, too.

    Chemotaxis is amazing stuff. Here’s some white blood cells demonstrating it:

    and doing the pretty much the same thing chasing some S. aureus in the famous 16mm film made by David Rogers:

    While reproducing this kind of motion is interesting, the really cool stuff is what happens inside cells, ranging from marshalling DNA to ATP-synthase and analogues.

    “Not exactly building life in a test tube, but the boundary grows increasingly blurry”

    Let’s wait until they can reproduce this sort of reproduction. This is a doubling of cells in a small patch of slime mould:

    And finally, an important bit of molecular machinery driven in either direction depending on which side has less entropy (protons packed into mitochondrondrial matrix -> rotate one way, releasing protons; ATP packed into intracellular fluid -> rotate the other way, moving protons into the mitochondrion).

  • Daniel Tung

    Hmm…A few weeks ago I was thinking of devising a technology to move any solid where the movers are invisible to naked eye. Some more, this is done with mind control.
    So it would appear that the things move on their own.


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Cosmic Variance

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About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] .


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