A large variety of two- and three-dimensional nanostructures have been constructed using DNA nanotechnology. Most of the construction methods require many different specially designed DNA molecules. Purdue University researchers have published a new DNA nanotech method that uses essentially one tile that self-assembles into a variety of larger three-dimensional shapes. Roger Highfield, Science Editor of the Telegraph (UK) describes the accomplishment:
… A team of scientists has created a versatile strategy for building three dimensional structures on the nanometre (billionth of a metre) scale by coaxing strands of DNA to [form] a basic building block that can then assemble spontaneously into complex three dimensional shapes over distances of around ten to twenty billionths of a metre.
…A variety of patterns and nanostructures have already been made from DNA, or alternatively DNA has been used as a glue to stick gold particles together, by making DNA molecules that interact just in the right way.
But larger and more complex three-dimensional structures are difficult to make using existing fabrication methods, which would require the use of hundreds of different DNA strands.
Today, in the journal Nature, Dr Chengde Mao of Purdue University, Indiana, and colleagues overcome this problem by programming DNA to fold first into a basic structural unit, akin to a basic building block that can be used to make more complicated shapes.
The Nature (abstract). The three-point star motif that Chengde Mao and his collaborators use as their basic building block has been used previously as a component in forming flat 2-D crystals. To make the tiles flexible enough to form polyhedra, they elongated the single-strand DNA loop in the center of the tile. A longer loop gives enough flexibility to form tetrahedrons; a shorter loop gives a less flexible tile, resulting in dodecahedrons. This work is a promising proof of principle, but how useful it turns out to be depends on the success of the next step. As the researchers conclude: “The current study used only DNA three-point-star motifs as primary building blocks, but we are currently investigating whether our hierarchical assembly strategy can be applied to other DNA motifs to prepare an even wider range of 3D objects.” I hope they succeed.
—Jim
