Nanorobots for medicine: how close are we?

Since the pioneering vision of Feynman in his now famous lecture ‘There’s Plenty of Room at the Bottom’ first delivered at an American Physical Society meeting at Caltech in December 1959 [1], film and scientific exploration at the nanoscale have been lending each other imagery and targets to achieve. It took only 5 years from Feynman’s lecture for a fellow resident of Los Angeles, Harry Kleiner, to complete the script for the film ‘The Fantastic Voyage’ that was released in 1965 to popularize ‘miniaturization for medicine’ like no scientist could ever do. The inspirational power of miniaturizing matter to navigate throughout the human body and reach the brain to remove aneurysm-causing blood clots depicted in the film, even transcended into the art world thanks to Salvador Dalí and his painting ‘Le Voyage Fantastique’ portraying the voyage in to the human subconscious, a result of the painter’s direct involvement in the production of the film (Figure 1). Today, 45 years after this first cinematography-originated use of nanotechnology for medicine, numerous scientists, thinkers, film makers and authors have been describing how this powerful technology can assist us to explore the nanoscale of the human body. However, one question still persists. Where do fantasy, imagination and science fiction stop and where does ‘real’ science and medicine start? The answer is that even though dramatic developments in technology and engineering at the nanoscale have occurred in the last decade, we are still at a state of infancy regarding the capability to design, manufacture, control and navigate nanorobots (nanomachines, nanobots, nanoids, nanites and nanonites or however else described) and purposefully use them for diagnosis or therapy. Some of the most critical challenges are discussed below.