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First Membrane Controlled By Light Developed 33

An anonymous reader writes with this excerpt: "A new membrane developed at the University of Rochester's Laboratory for Laser Energetics blocks gas from flowing through it when one color of light is shined on its surface, and permits gas to flow through when another color of light is used. It is the first time that scientists have developed a membrane that can be controlled in this way by light."
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First Membrane Controlled By Light Developed

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  • by Anonymous Coward

    When they can make "go" the proper green color. And red for "stop." And yellow should make the gas really go fast.

  • This is actually a pretty interesting breakthrough. I'd like to see some of the information about the crystals themselves, but it seems pretty straightforward.

  • I don't know why, but the first thing that came to my mind is that perhaps this could be used in an artificial heart. No moving parts (the valves anyway) and precise low power way to block and allow blood flow. Hmm...
    • They said it allows "gas" through; not gigantic blood cells... (yes, compared to gas, blood cells are like continents)
    • I was thinking more like an artificial lung. Sensors could determine CO2 or O2 content and allow gas exchange based on the content of the gas.

      • by bknack ( 947759 )

        Now that sounds even better (since the membrane is currently used with gas).

        Even though my response (especially since it involves a fairly thick fluid - not a gas) and yours may not be applicable at the moment, I think they both suggest distant goals that would change the world as we know it.

        Cheers, Bruce.

  • understanding life (Score:4, Informative)

    by JumpingBull ( 551722 ) on Sunday August 01, 2010 @03:52PM (#33102996)

    This is, IMHO, important to understanding, and perhaps tailoring, smart membranes that mimic the actual membranes found in cells.

    As an analogy, in a leaf the transpiration of carbon dioxide and water is controlled by small pores, called stoma. These stoma are less abundant in succulents, like cacti, or aloe vera, then in rain forest vegetation.

    The organelles of a cell, like the mitochondria, have similar properties.

    This is another piece of the puzzle for nanotechnology, and may find use in batteries and electrochemical fuel cells. Time will tell.

  • by pz ( 113803 ) on Sunday August 01, 2010 @04:57PM (#33103578) Journal

    For a few years now, we've been able to control the porosity of membranes in vivo, not just in a laboratory dish, by exposing them to light. The work started at Caltech, where, a little over ten years ago, someone demonstrated the first cellular membrane channel that could be turned on and off by light -- it was a potassium channel (that is, a pore specially designed so that it only passed potassium ions) if I recall correctly. More recently, and more famously, a fellow at the MIT Media Lab was able to engineer rhodopsin (one of the pigments of the photo-sensitive cells in the retina) into similar ion channels resulting in much more efficiently controlled ion-specific porosity.

    Again, this is work that has been done in whole living animals, not inanimate substance, a far more impressive feat. I've seen presentations where a mouse's behavior was controlled through turning on or off light going into an optical fiber implanted in its brain. The light controled the porosity of the cell membranes of neurons in a particular part of the brain: turn the light on, channels / pores are opened exiting the cells; turn the light off, channels are closed, quieting the cells down. (For those familiar with this work, I admit that this is a gross simplification for the purposes of the present argument.)

    While the work at U. Rochester sounds interesting, the researchers there are certainly not the first to control membrane porosity through light. That, and the past tense of "to shine" is "shone".

  • Sunlight control (Score:4, Insightful)

    by soundguy ( 415780 ) on Sunday August 01, 2010 @05:00PM (#33103610) Homepage
    My first thought is that it would be useful to automatically control aspiration/respiration of something during daylight hours, with the sun providing ultraviolet light. Just can't think of an immediate application.
    • by bknack ( 947759 )

      Just kidding of course, but this reminds me of vampires :)

      On a more serious note, what about some kind of sunscreen?


  • Condoms. Something to do with condoms.

    I don't know what, exactly ... responding to bioluminescent fungi?

    • Is that so you can try to get someone pregnant... unless they have a fungal infection? I think in general, the people who are worried about their sexual partner having STDs probably isn't trying to get them pregnant.
  • Locks On/Off (Score:4, Interesting)

    by Doc Ruby ( 173196 ) on Sunday August 01, 2010 @11:08PM (#33106536) Homepage Journal

    Something interesting about these optically-actuated gateways is that they are (more or less) locked to open or closed by each of the different frequency "keys" shifting their state, not requiring continuous illumination:

    When purple light illuminates the surface of the membrane, the dye molecules straighten out and the liquid crystals fall into line, which allows gas to easily flow through the holes. But when ultraviolet light illuminates the surface, the dye molecules bend into a banana shape and the liquid crystals scatter into random orientations, clogging the tunnel and blocking gas from penetrating.

    When the gas that the membrane controls can be made to emit one or another of the frequencies when its physical or chemical properties change, this material will become a "gas transistor", which will allow gas to control its own distribution determined by what physical/chemical state it's in.

  • 2nd Law Ahoy! (Score:3, Insightful)

    by schmidt349 ( 690948 ) on Sunday August 01, 2010 @11:45PM (#33106718)

    Maxwell's demon could not be reached for comment.

Adding features does not necessarily increase functionality -- it just makes the manuals thicker.