For questions about technology that works with sizes of less than 100 nanometers, often the manipulation of individual molecules.
Nanotechnology or "nanotech" is the manipulation of matter on an atomic, molecular, and supra-molecular scale.
Nanotech can be a great bugaboo and often is given both more and less credit then it is capable of. Michael Crichton's Prey novel is an excellent example. Parts had realistic expectations and parts were not even possible by the rules of physics, or programming.
Just using small particles doesn't qualify a technology as nanotechnology: e.g. carbon black used in tires is not nanotechnology despite being very small particles.