Fascinating new technique to identify specific DNA sequences

by seattleniceguy 6 Replies latest jw friends

  • seattleniceguy


    Researchers at the University of Pittsburgh and at Nanomix in California have discovered a new way of detecting specific DNA sequences, at the resolution of a single base.

    The device is simple and elegant. An ordered sequence of electrodes is overlayed with a random mesh of carbon nanotubes, as in the following image:

    The visible maze-like sequence in the left image is the electrodes. In the right image, you can see a random mesh of tiny carbon nanotubes. Electric current can flow through the circuit by using the carbon nanotube mesh as a bridge.

    The carbon nanotubes are then bathed in a solution containing a DNA sequence that is complementary to the one to detect. So for example, if you were looking for the sequence AACCGGTT, you would create the sequence TTGGCCAA, multiply it a few million times, and coat the carbon nanotube mesh with it. (As a reminder, in DNA, the bases A and T, and C and G, respectively, always pair up together.)

    Next, you place a drop of subject blood on the circuit. If the matching DNA sequence is present, it will bond to the complementary sequences, which are connected to the carbon nanotube mesh. Current passing through the device drops dramatically, indicating a match.

    One real-world application for this would be for an instantaneous, highly accurate field-test for specific viruses. For example, currently, officials are testing birds all over the world for bird flu. This technology could provide real-time test results, dramatically improving our ability to recognize and contain the virus. The technology should be cheap to manufacture because the nanotubes do not need to be ordered. The electrodes are spaced at the micrometer scale, which means they can easily be created using conventional manufacturing techniques.


  • JamesThomas
    they can easily be created using conventional manufacturing techniques.

    I hammered and chiseled out a few today actually. Anyone want their favorite chicken tested for the flue?

    Speaking of which, I just heard on the news that in order to get a handle on the bird flue, President Bush has ordered a preemptive bombing strike of the Canary Islands.


  • Gerard

    I see no advantage over the traditional Polymerase Chain Reaction (PCR) method. But if the machine is small enough to do field work then it is a useful improvement.

  • skyman

    I think it will have great advantages, the leaps and bounds in this field truly is amazing.

  • seattleniceguy

    LOL @ JamesThomas.


    I think the main advantage is that no laboratory is required. The test could be performed quickly in the field.


  • Midget-Sasquatch

    Gerard: Yeah, its sort of like PCR in a way, in that there are dna primers to which the targetted sequences (if present) will bind to. But the advantage, if I'm not mistaken, is its portability and its speed. Just like SNG said.

    Think about all the time saved instead of going through repeated cycles of melting, copying, and annealing to amplify the target sequence. (The analogous step having been done already to have the nanotubes coated with the primer like sequences). You don't have to carry a mini-fridge for the needed enzyme etc.

  • tetrapod.sapien


    The technology should be cheap to manufacture because ...

    you work for M$, don't you? lol, you should know better.

    cool man. pretty amazing stuff. so basically we're headed right for a bio-revolution? i figure that with about ten grand, i could be doing some of this stuff in my garage. which are what revolutions are made of, hey? hackers.


Share this