Nanorobotics is concerned with:
1) Design and fabrication of nanorobots with overall dimensions at or below the micrometer range and made of nanoscopic components
2) Programming and coordination of large numbers (swarms) of such nanorobots
3) Programmable assembly of nanometer-scale components either by manipulation with macro or micro devices, or by self-assembly on programmed templates.
Nanorobots have overall dimensions comparable to those of biological cells and organelles. This opens a vast array of potential applications in environmental monitoring for microorganisms and in health care. For example, imagine Artificial cells (nanorobots) that patrol the circulatory system, detect small concentrations of pathogens, and destroy them. This would amount to a programmable immune system, and might have far-reaching implications in medicine, causing a paradigm shift from treatment to prevention. Other applications such as Cell repair might be possible if nanorobots were small enough to penetrate the cells.