In my view, the greatest recent innovation in molecular engineering is the development by Paul Rothemund at Caltech of a method that enables the design and fabrication of 3D, million-atom-scale, atomically precise structures by one person in a single day. Structures of this kind can be used to organise diverse molecular components on an unprecedented scale. He calls this ‘DNA origami’.

Eric Drexler is author of Engines of Creation and Nanosystems: Molecular Machinery, Manufacturing, and Computation. He is chief technical advisor of Nanorex.