Nanotechnology has emerged as a promising vehicle for an emerging scientific and technological revolution. Richard Feynman, in his seminal 1959 lecture, proposed a variety of potential nanomachines, which could be engineered to a higher level of functional efficiency than currently available manufactured devices by exploiting changes in the behavior of matter at the nanometer length scale. In order to realize this goal, scientists and engineers have to devise strategies to synthesize specified functional nanoparticles, and then learn how to incorporate them into devices in which they might function individually or in cooperation with other nanoparticles or devices. This "bottom up" approach of "nanoparticle design" followed by "device assembly from nanoparticles" is widely accepted as a promising route to nanotechnological applications, separate from a more traditional "top down" approach followed in semiconductor and electronics research. In recent years, "bottom up" nanotechnology has led to promising innovations in fields such as biotechnology, electronics and catalysis.