Nanotechnology is all about making things small—-and thin. So sometimes the magic is not making it tiny but making it incredibly thin, only a few atoms or molecules thick. The big thing about making thin things is making sure that even though it is thin, it is uniform, meaning no holes. And that is hard. Imagine spreading peanut butter just a few molecules thick? Tough. Now scientists have figured out how to make layers of glass only a few molecules thick. Glass is made of silicon dioxide and is pretty impermeable. A layer 15 to 30 molecules thick (about 1/500 the width of a hair) prevents bacteria from penetrating and so you could make a bacteria proof coating. It is also impermeable to water meaning it doesn’t stain.  What is neat is that glass at that thickness is transparent (well that is not surprising) but it is also flexible! Meaning you could coat lots of different things. Maybe you wouldn’t want to eat it but it is might be useful for stain resistance or to make things really slick like the front end of a high speed train. http://tiny.cc/0uhtC