Editing Molecular nanotechnology (section)

===Smart materials and nanosensors===
Any sort of material designed and engineered at the [[nanometer]] scale for a specific task is a [[smart material]].  If materials could be designed to respond differently to various molecules, for example, artificial drugs could recognize and render inert specific [[viruses]].  [[Self-healing material|Self-healing structures]] would [[Regeneration (biology)|repair]] small tears in a surface naturally in the same way as human skin.

A nanosensor would resemble a smart material, involving a small component within a larger machine that would react to its environment and change in some fundamental, intentional way.  A very simple example: a photosensor might passively measure the incident light and discharge its absorbed energy as electricity when the light passes above or below a specified threshold, sending a signal to a larger machine.  Such a sensor would supposedly cost less{{according to whom|date=June 2019}} and use less power than a conventional sensor, and yet function usefully in all the same applications &mdash; for example, turning on parking lot lights when it gets dark.

While smart materials and nanosensors both exemplify useful applications of MNT, they pale in comparison with the complexity of the technology most popularly associated with the term: the replicating [[nanorobot]].