1. Manufactured nanomaterials: a growing industry

The development of nanoscience and nanotechnology accelerated in the 2000s. At the interface between physics, chemistry and biology, they study and put into practice the design and use of nanomaterials. Nanomaterials are defined as assemblies of a few hundred to a few thousand atoms, resulting in an object smaller than 100 nm (1 nm = 10 ^–9 m). By way of comparison, a spherical nanomaterial 10 nm in diameter will be 100 times larger than an atom and 5 times larger than a DNA molecule. A virus has an average size of 100 nm, and a human cell measures around ten thousand nanometers. Nanomaterials fall into three categories:

• nanoparticles, whose three dimensions are less than 100 nm ;

• nanotubes with one dimension greater than 100 nm, which can be considered fibers if...