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.
Long, single strands of DNA, plus strengthening shorter strands, were used to make this image
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.
DNA has long been known for its versatility as a microscopic building block.
The molecule can be 'cut' using enzymes and reassembled using matching rungs in its double-helix structure.
This theoretically opens the way to making DNA quantum computers and nano-level devices including injectable robots that can monitor the body's tissues for good health.
But, until now, nano-assembly has been a complex atom-by-atom procedure that is also costly, because it is carried out in a vacuum or at extremely coldly temperatures.
Rothemund, writing in today's issue of the journal Nature, describes a far simpler and much cheaper process in which long, single strands of DNA can be folded back and forth to form a basic scaffold.
This technology might be used to make nano-cages, a way of sequestering enzymes in pharmaceutical research
The basic structure is then supplemented by around 200 shorter strands, which both strengthen it and act rather like pixels in a computer or TV image, thus providing a shape that can bear a complex pattern.
In a potent demonstration of his so-called DNA origami technique, Rothemund has created half a dozen shapes, including a five-pointed star, a snowflake, a picture of the double helix and a map of the Americas in which one nanometre represents 120 kilometres.
Rothemund has been working on flat, two-dimensional shapes but says that 3D structures in DNA should be quite feasible with this technique.
One application would be a nano-scale 'cage' in which pharmaceutical researchers, working on novel drugs, could sequester enzymes until they were ready for use in turning other proteins on and off.
Long, single strands of DNA, plus strengthening shorter strands, were used to make this image
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.
DNA has long been known for its versatility as a microscopic building block.
The molecule can be 'cut' using enzymes and reassembled using matching rungs in its double-helix structure.
This theoretically opens the way to making DNA quantum computers and nano-level devices including injectable robots that can monitor the body's tissues for good health.
But, until now, nano-assembly has been a complex atom-by-atom procedure that is also costly, because it is carried out in a vacuum or at extremely coldly temperatures.
Rothemund, writing in today's issue of the journal Nature, describes a far simpler and much cheaper process in which long, single strands of DNA can be folded back and forth to form a basic scaffold.
This technology might be used to make nano-cages, a way of sequestering enzymes in pharmaceutical research
The basic structure is then supplemented by around 200 shorter strands, which both strengthen it and act rather like pixels in a computer or TV image, thus providing a shape that can bear a complex pattern.
In a potent demonstration of his so-called DNA origami technique, Rothemund has created half a dozen shapes, including a five-pointed star, a snowflake, a picture of the double helix and a map of the Americas in which one nanometre represents 120 kilometres.
Rothemund has been working on flat, two-dimensional shapes but says that 3D structures in DNA should be quite feasible with this technique.
One application would be a nano-scale 'cage' in which pharmaceutical researchers, working on novel drugs, could sequester enzymes until they were ready for use in turning other proteins on and off.