<unk>  is a highly multidisciplinary field, drawing from fields such as applied physics, materials science, interface and colloid science, device physics, supramolecular chemistry (which refers to the area of chemistry that focuses on the noncovalent bonding interactions of molecules), self-replicating machines and robotics, chemical engineering, mechanical engineering, biological engineering, and electrical engineering. Grouping of the sciences under the umbrella of<unk> " has been questioned on the basis that there is little actual boundary-crossing between the sciences that operate on the nano-scale. Instrumentation is the only area of technology common to all disciplines; on the contrary, for example pharmaceutical and semiconductor industries do not "talk with each other". Corporations that call their products<unk> " typically market them only to a certain industrial cluster.
Two main approaches are used in<unk> . In the "bottom-up" approach, materials and devices are built from molecular components which assemble themselves chemically by principles of molecular recognition. In the "top-down" approach, nano-objects are constructed from larger entities without atomic-level control. The impetus for<unk>  comes from a renewed interest in Interface and Colloid Science, coupled with a new generation of analytical tools such as the atomic force microscope (AFM), and the scanning tunneling microscope (STM). Combined with refined processes such as electron beam lithography and molecular beam epitaxy, these instruments allow the deliberate manipulation of nanostructures, and lead to the observation of novel phenomena.
Examples of<unk>  are the manufacture of polymers based on molecular structure, and the design of computer chip layouts based on surface science.  Despite the promise of<unk> es such as quantum dots and nanotubes, real commercial applications have mainly used the advantages of colloidal nanoparticles in bulk form, such as suntan lotion, cosmetics, protective coatings, drug delivery, and stain resistant clothing.
Nanotechnology
Organic chemistry
Biotechnology
Surface science
Mobile health
Clinical engineering
Health science
Bioenergetics