Smart materials are a class of nanomaterials that respond to changes in the environment
such as a drop in temperature or pH. An environmental change could trigger a physical or
chemical effect that mimics a natural mechanism in the body. For example, applications
could include a smart polymer that flexes with mechanical strength as an artificial
muscle, or a hydrogel that dissolves according to body chemistry to more efficiently
deliver drugs.

When attached to or embedded in a structure, smart materials can potentially sense
disturbances, or trigger physical reactions with force in actuators, piezo sensors, and
shape memory metals. It is possible to have smart materials used in the body to exceed
current human performance on multiple dimensions, and detect environmental conditions
beyond current human limits.