Nanotechnology and nanoengineering are producing significant scientific and technological advances in diverse fields including medicine and physiology. In a broad sense, they can be defined as the science and engineering involved in the design, synthesis, characterization, and application of materials and devices whose smallest functional organization in at least one dimension is on the nanometer scale, ranging from a few to several hundred nanometers. A nanometer is one billionth of a meter or three orders of magnitude smaller than a micron, roughly the size scale of a molecule itself (e.g., a DNA molecule is about 2.5 nm long while a sodium atom is about 0.2 nm).
To give an appreciation of just how significant an order of magnitude is, let alone three orders when going from micron to nanometer scales, consider that no one would ever walk from New York to San Diego, but with a single order of magnitude change in speed (the equivalent of changing speed from walking to driving), you would get to San Diego across the United States in about 2 days. Flying, which would be two orders of magnitude faster than walking, would get you across the United States in a few hours, and in a supersonic plane (or three orders faster than walking), it would take you minutes. (Walking a straight line between the two cities would take about 42 days at an average speed of 3 miles per hour.)
The potential impact of nanotechnology stems directly from the spatial and temporal scales being considered: Materials and devices engineered at the nanometer scale imply controlled manipulation of individual constituent molecules and atoms in how they are arranged to form the bulk macroscopic substrate. This, in turn, means that nanoengineered substrates can be designed to exhibit very specific and controlled bulk chemical and physical properties as a result of the control over their molecular synthesis and assembly. For applications to medicine and physiology, these materials and devices can be designed to interact with cells and tissues at a molecular (i.e., subcellular) level with a high degree of functional specificity, thus allowing a degree of integration between technology and biological systems not previously attainable.
The potential impact of nanotechnology stems…