Saturday, May 20, 2006

"Biologically inspired nanofabrication" - Dan Morse

Consider the silica structures that comprise the shells of diatoms. The precision of nanoscale architectual control of the silica shell fabrication process exceeds human technology. The fabrication process is very mild, by human standards: low temperatures, high yields, etc. The scale of production is enourmous - "gigatons!"

Much of the current work has been focused on sponge organisms that naturally built silica structures. One of these sponges that can be dissolved into essentially a handful of glass needles. Research has indicated proteins form a backbone in the center of these needles. Further research indicated that silicateins (the axial proteins within the needle) are homologous to hydrolases, suggesting that they may be enzymatically active - as catalysts! "These proteins, at neutral pH and low temperature, catalyze and template synthesis of silica from SI-alkoxides." (The source of silicon in biological fabrication systems is silicic acid.)

So, on might ask, could this protein do the same from metal oxide precursors? Perhaps.

How does the silacatein work? It perhaps self-assembles into a giant irregular array in which the precursors bind and are catalyzed into the crystal. Now then, don't blink: the catalyst is the template! "That's a design principle; I don't know of any other enzymes, not even DNA polymerase, that acts as its own template." (what about prions?)

"Could we extract the principles that nature has evolved, and do it without the biology? And does that later intersect with Synthetic Biology? That is my question to you."

Dr. Morse then went on to describe how he used those principles to construct a novel material that was comprised of a conductive back plate from which sprouted a forrest of nearly perpendicular cobalt-hydroxide plates. It's a p-type semiconductor. It's got a high surface area, and an extremely high purity, because the process never needed them (it was just a vapor deposition of a modified catalyst onto the oxide precursor... I think) - perhaps it could be very useful in energy applications. Because they contain no organics, the fabrication methods are "fully integrable with existing nanoscale (CMOS) methods."

Dr. Morese concluded with octopuses... or more specifically that octopuses posses adaptive, flexible, multifunction arrays in three layers in their skin for adaptive camouflage. This could be a great foundation for a new kind of flexible display system.

This was a great talk, a little technical at times, but very fascinating. Dr. Morese, like Arash Komeili before him, is an extremely good speaker, and he was able to present the material in a lucid and engaging way. Check out the webcasts of their presentations.

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