“A nanotechnologist has created the world’s smallest and most plentiful smiley, a tiny face measuring a few billionths of a metre across assembled from strands of DNA. Dr Paul Rothemund at the California Institute of Technology can make 50 billion smileys, each a thousand times smaller than the diameter of a human hair, with his technique.”
Ref: Paul W. K. Rothemund (2006) “Folding DNA to create nanoscale shapes and patterns”, Nature 440:297-302 (16 March 2006) doi:10.1038/nature04586
