They used a process called DNA origami, they manipulated strands of genetic code gene strands to fold and assemble into the right shape. Scroll down for videoThe world's smallest Mona Lisa has been made using microscopic tiles of DNA. THE HISTORY OF DNA ORIGAMI In 2006, Caltech's Paul Rothemund developed a method to fold a long strand of DNA into a prescribed shape. The technique, dubbed DNA origami, enabled scientists to create self-assembling DNA structures that could carry any specified pattern, such as a 100-nanometer-wide smiley face. DNA origami revolutionised the field of nanotechnology, opening up possibilities of building tiny molecular devices or 'smart' programmable materials.

Source: Daily Mail December 08, 2017 15:56 UTC