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IBM writes with AFM down to 10 molecules

Foresight member John Faith brings our attention to an achievement at IBM Almaden here in Silicon Valley: they have found a way to separate and then “write” very small deposits of specific molecules — as few as 10 molecules — onto a substrate:

“IBM researchers have demonstrated a new nanoscale method that both rapidly separates very small numbers of molecules and also delivers them precisely onto surfaces with unprecedented control…

” ‘Our initial tests used fragments of DNA – one with five base pairs, another with 16,’ said H. Kumar Wickramasinghe, IBM Fellow and co-developer of several different types of AFMs. ‘An electric field propelled these molecules down the 11.2-micron length of the AFM tip in 5 and 15 milliseconds, respectively. We controlled the passage of as few as 10 molecules, which indicates that this approach should be very useful for analyzing very small biological samples and in writing extremely small features.’ ”

Published in the May 1, 2006 Applied Physics Letters, the work was also co-authored by Jane Frommer and Kerem Unal, both of IBM Almaden. Special congrats to Dr. Frommer, a longtime Foresight participant.

From the abstract: “An atomic force microscope (AFM) is tailored to perform ultrafast electrophoretic differentiation of molecules on populations of <0.1 zeptomoles (10–22 moles) on the surface of a probe tip.” Zeptomoles! —Christine

One Response to “IBM writes with AFM down to 10 molecules”

  1. eoin clancy Says:

    The key word here is speed. this system is… “approximately five orders of magnitude faster than in conventional capillary electrophoresis”… Also of interest is the possibility of using this technique in parallel, with their inhouse millipede technology (where IBM have created an array 4096 cantilevers on a 6.4mm x 6.4mm substrate).

    Detection of molecules in the zeptomole range are no longer very unusual. Detection limits in this range (for nucleic acids) are routinely achieved with quantitative PCR. There are also several other assays out there with these ranges of sensitivity eg the bio-barcode assay being developed by Chad Mirkin and Nanosphere

    0.1 zeptomoles are actually 100 yoctomoles…. Kinda reminds me of the work done by Andrew Briggs et al, when they created a yocto liter test tube! See here for the article

    On the side, I love the word zepto, so much so, I named my then small goldfish Zepto. I think he’s now an atto sized goldfish!


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