EVANSTON, Ill. -- Ever since the invention of the first scanning probe microscope in 1981, researchers have believed the powerful tool would someday be used for the nanofabrication and nanopatterning of surfaces in a molecule-by-molecule, bottom-up fashion. Despite 25 years of research in this area, the world has hit a brick wall in developing a technique with commercial potential -- until now. Northwestern University researchers have developed a 55,000-pen, two-dimensional array that allows them to simultaneously create 55,000 identical patterns drawn with tiny dots of molecular ink on substrates of gold or glass. Each structure is only a single molecule...