Nanotechnology involves systems on the order of one-thousandth the thickness of a human hair. Generally, a nanoparticle or nanosystem has an outer shell that protects an inner core of therapeutic molecule or diagnostic substance. Either the shell or core can be made up of polymers or metals (Figure). The small size and enormous surface area:volume ratio create uniquely advantageous abilities to enter cells, release drugs slowly over time, modulate small-molecule payload toxic effects, and, in some cases, amplify a signal that depends on surface contacts. Nanotechnology currently affects 3 distinct areas of medicine: therapeutics, diagnostics, and imaging. The potential in each of these areas is enormous.
Langer R, Weissleder R. Nanotechnology. JAMA. 2015;313(2):135-136. doi:10.1001/jama.2014.16315