Nanoparticles are all around us.
Some are man-made, others occur naturally.
Because they're so tiny - one nanometre is one billionth of a metre - nanoparticles can only be seen through an electron microscope.
Nanoparticles have unique physical properties, and scientists are looking for ways to exploit these characteristics.
Nanoparticles are currently used in medicine, in food, in clothes and cosmetics.
In the future, nanoparticles could also be used to help improve energy generation and storage.
They might also help us remove contaminants from polluted water.
In the first of two programmes about nanotechnology, Richard Hollingham investigates how a better understanding of the properties of nanoparticles is helping researchers develop new medical treatments.
Richard hears more about their characteristics and potential from Richard Moore at the Institute of Nanotechnology in Stirling.
Richard then talks to Dr Simon Holland and Wendy Knight at GlaxoSmithKline about research into using nanoparticles to deliver therapeutic agents to precise locations in the body.
Richard also visits MagForce, a German research company, that's developing a novel therapy using heated nanoparticles of iron oxide to destroy brain cancers.