Nanotechnology is the manipulation of matter on an atomic, molecular and supramolecular scale. The earliest and most widespread description of nanotechnology refers to the particular technological purpose of precisely manipulating atoms and molecules for the manufacture of macroscale products, also called molecular nanotechnology. The National Nanotechnology Initiative set out a more general description of nanotechnology, which defines nanotechnology as the manipulation of matter with at least one dimension of 1 to 100 nanometers. This definition reflects the fact that quantum mechanical effects are important on this scale of the quantum realm, so the definition shifted from a particular technological objective to a category of research that includes all types of research and technologies that deal with special properties of the matter occurring below the given size threshold. Therefore, it is common to see the plural "nanotechnologies" as well as "nanoscale technologies" to refer to the wide range of research and applications whose common feature is size. Because of the variety of potential applications (including industrial and military), governments have invested billions of dollars in nanotechnology research. Until 2012, through its National Nanotechnology Initiative, the US have invested $ 3.7 billion, the European Union has invested $ 1.2 billion and Japan has $ 750 million.
Nanotechnology, as defined by size, is naturally very broad, including fields of science as diverse as surface science, organic chemistry, molecular biology, semiconductor physics, microfabrication, molecular engineering, and so on. the physics of the device to completely new approaches based on molecular self-assembly, from the development of new materials with nanoscale dimensions to the direct control of atomic-scale matter.
Scientists are currently discussing the future implications of nanotechnology. Nanotechnology may be able to create many new materials and devices with a wide range of applications, such as nanomedicine, nanoelectronics, bio-materials for energy production and consumer products. On the other hand, nanotechnology raises many of the same issues as any new technology, including concerns about the toxicity and environmental impact of nanomaterials, and their potential effects on the global economy, as well as speculation on various apocalyptic scenarios. These concerns have led to a debate between advocacy groups and governments over whether a special regulation of nanotechnology is justified.