Nanosphere

**Semantic type:** Classification

**Definition:** Self-assembling durable silica spheres that fit inside each other. These spheres range in size from 2 to 50 nanometers and form within seconds. They are small enough to be introduced into the body and have uniform pores that facilitate the controlled release of drugs. The spheres also have the capability to absorb both organic and inorganic substances. For example, nanoparticles can absorb small particles of iron, thereby allowing magnetic control. Thus, the contents of nanospheres can be released upon activation.