Although there are many life forms on this planet and they eat various things, some of them don't need oxygen, but some do. Some can live off sulfur, others can live off other energy sources, but all these life forms function only in water. What we'd like to do is have a technology to build things on the same principle of one atom at a time in the right place but not to have to have water around. That is what we call the dry side of this huge area of nanotechnology. Well, one of the key virtues is metallic behavior.
Metals are great but on a nanometer scale they react explosively with water.
If we could develop a dry nanotechnology for making tiny metallic objects, there's a whole range of incredibly important technologies that would result. For example, how about a metallic wire that is only a nanometer in diameter. In fact, that is what we are trying to produce here in our laboratory with long buckytubes we call buckyfibers. The fibers are made out of carbon in a hexagonal lattice wrapped around to make a long hollow tube sort of like a soda straw. The carbon tube itself is unreactive with water, but it is also impenetrable.