In the latest phase of the nanotechnology revolution, scientists have built a collection of minuscule objects from DNA, including toothed gears, curved tubes, and a wireframe beach ball five millionths of a centimetre in diameter.

As well as being able to hold vast amounts of information, DNA is tough and flexible, making it an attractive candidate for use as a nanomaterial. Advances in molecular biology in recent decades have meant that scientists are well equipped to work with DNA and program it to do whatever they want.

"The main advantage of DNA is that we understand it," said Hendrik Dietz, now head of the Laboratory for Biomolecular Nanotechnology at München Technical University in Germany. "DNA is the only material that we can program at the nanoscale."

The building blocks of DNA can be made to assemble themselves, piece by piece, into a structure designed by the researcher.

"We have a bunch of small parts that are floating around in solution, bumping into each other," explains William Shih of Harvard University, who also worked on the study. "Sometimes when they bump into each other in the way that we want them to they don't let go, and through many cycles of this bumping into each other and sticking, eventually we end up with the desired shape – if we've programmed the structure of the molecules correctly."

Dietz, Shih and their colleague Shawn Douglas used this method to build tiny components that could, in principle, be assembled into more complex functional devices. A commentary accompanying their paper in the journal Science observes: "It is as if DNA has been subjected to the practice of yoga to display a variety of different postures at the nanoscale."

The structures are made from bundles of double-helix DNA strands. By altering the length, number and arrangement of strands, the scientists were able to construct several 3D shapes.

To make the bundle bend, for example, they added pairs of nucleotides – the basic building blocks of DNA – on one side of the bundle, making that side slightly longer, and deleted nucleotide pairs on the other. This allowed them to finely control the curvature of their structures.

This is the first time that scientists have created truly curved DNA nanostructures. Previously scientists have only managed to make straight or kinked structures.

Computer graphic of nanoscale toothed gears made from DNA (left) and electron micrographs of the actual nanostructures. Photograph: Science/AAAS

The next step was to put together a number of curved subunits to make more complex 3D structures, which the researchers designed with the help of a graphical software tool they developed specially for the task. Finally, they photographed the nanostructures using an electron microscope to confirm they had achieved the desired shapes.

Dietz is confident that DNA nanostructures will come into their own in a range of applications.

"In the short term, I would say that the immediate applications are in basic science research. Now we have a biomaterial that we can program at the nanoscale to address questions in biophysics or nanochemistry."

In the longer term, he envisages constructing medical devices "that could get into cells and might be capable of performing some job there".

Like any sensible scientist working at the cutting edge, he acknowledged there was some way to go. "We're still struggling with defects, but I'm optimistic that there are a lot of applications that we can use in the future."