Nanotechnology-the building and control of stuff at the molecular level-is being used to invent and test new types of antibiotics. One approach is to use small, circular peptides that coalesce or "self-assemble" into tubes that can puncture the membranes of bacterial cells and kill them, but that ignore the membranes of animals including humans. This design approach uses new proteins, rather than screening and testing proteins produced by microbes. This strategy is intended to speed the development of new antibiotics and to try to keep ahead of the rate of mutation and resistance among bacteria that cause diseases. http://www.nature.com/nbt/press_release/nbt0801.html