At the nanoscale level, the physical, chemical, and biological properties of materials differ in fundamental, and often valuable, ways from the properties of individual atoms and molecules, or bulk matter. Research and development in nanotechnology is directed towards creating im-proved materials, devices, and systems that exploit the new properties. The specific properties of nanoparticles proved to be very useful for an increasing number of commercial applications, such as protective coatings, light-weight materials or self-cleaning clothing, for example.