Sunday, March 26, 2006
DIATOMS AND NANOTECHNOLOGY
After the post about diatoms I remembered an article about them and nanotechnology so I went looking through the files. That was a lost afternoon of browsing through articles I had forgotten about. Now I have a list of googles to see if any of them have updates which means more lost hours as I go through NASA images.
I found the article and it was harder to understand than I thought but after a few readings I had it straight. The problem is that even with so many Startrek episodes under my belt I still have trouble getting my mind around nanotechnology. It's the minuteness of the nano structures and the fact that powering these are more minute engines. To create microscopic devices to exact specifications, a scientist has to push single atoms around using an atomic force microscope but now nanotechnololgists are looking at the silica shells of diatoms.
Diatoms are single cell algae that have beautiful and elaborate glass shells. Looking at the photograph, you can see the variety of shapes the shells come in so instead of trying to build nano parts, scientists are working out how to convert the fragile glassy shells into tough ceramic.
Diatoms also create an array of intermediate structures as their shells mature. They have hollow hexagons, discs and barrell hoops, all suitable for micro machine components.
A ceramic chemist in America has already invented one process to change diatom shells atom by atom from glass into other substances. Compounds such as titanium oxide which changes its electrical resistance when exposed to different gases or calcium phosphate (bones) which could be used in drug-delivery devices or shield implanted cells from the immune system. Other scientists are looking at the pores in the shells (see photo) to use for growing nano crystals but even these pores are still too big. See what I mean about trying to get the mind around the size of nano machines.
Even with the diversity of the diatom shells, researchers are looking at how to make the shells to human specifications by various methods including gene transfer but other scientists aren't so sure.
As one diatomist admits that what diatoms do in the wild and what they can be forced to do in an industrial vat may not be the same thing.
I just think they're beautiful. It looks like this blog might get a bit geeky over the next few weeks so I'd better go trawling the net to find some pretty men to break up the nerdiness.