Self-assembling DNA ‘building blocks’ could create drug-delivery machines

May 31, 2012

Wyss researchers have built numerals, letters, and a number of other structures using short strands of DNA as building blocks (credit: Wyss Institute)

Wyss Institute researchers have developed a method for building complex nanostructures out of short synthetic strands of DNA.

Called single-stranded tiles (SSTs), these interlocking DNA “building blocks,” akin to Legos, can be programmed to assemble themselves into precisely designed shapes, such as letters and emoticons.

Further development of the technology could make it possible to create new nanoscale devices — to deliver drugs directly to disease sites, for example.

DNA nanotechnology

In an emerging field of science known as DNA nanotechnology, DNA is being explored for use as a material for building tiny, programmable structures for diverse applications.

The researchers developed an alternative to conventional DNA origami (using a single long biological strand of DNA, which acts as a backbone along which smaller strands bind to its many different segments, to create shapes).

Instead of a long strand, each SST is a single, short strand of DNA. One tile will interlock with another tile if it has a complementary sequence of DNA. If there are no complementary matches, the blocks do not connect. In this way, a collection of tiles can assemble itself into specific, predetermined shapes through a series of interlocking local connections.

In demonstrating the method, the researchers created more than one hundred different designs, including Chinese characters, numbers, and fonts, using hundreds of tiles for a single structure 100 nanometers (billionths of a meter) in size. The approach is simple, robust, and versatile.

Drug-delivery machines 

As synthetically based materials, the SSTs could have some important applications in medicine. SSTs could organize themselves into drug-delivery machines that maintain their structural integrity until they reach specific cell targets, and because they are synthetic, can be made highly biocompatible.

The technology was developed by a research team led by Wyss core faculty member Peng Yin, Ph.D., who is also an Assistant Professor of Systems Biology at Harvard Medical School.

The research was supported by the Office of Naval Research, the National Science Foundation, the National Institutes of Health, and the Wyss Institute at Harvard University.

Ref.: Bryan Wei, Mingjie Dai, Peng Yin, Complex shapes self-assembled from single-stranded DNA tiles, Nature, 2012, DOI: 10.1038/nature11075