When we talk about the nano world, we're actually talking about the world of atoms and molecules. The sizes of atoms differ, depending on their chemical elements and the way these elements bond, but the range is generally accepted as 0.1 to 0.2 nanometers.

The viruses that cause the common cold and other diseases are from several dozen to several hundred nanometers in length, while the smallest bacteria are over a micron (1,000 nm).

Nanotechnology today involves the manipulation of atoms and molecules to build structures or control the growth of substances on a scale the size of viruses, which are even smaller than bacteria, thereby creating novel capabilities and outstanding properties.