Researchers have created and programmed robots the size of a single molecule that can move independently across a nano-scale track, an advancement that could someday lead to molecular robots that can fix cells or assemble nanotechnology products.

The project was led by Milan N. Stojanovic, faculty member in the division of experimental therapeutics at Columbia University, who partnered with Erik Winfree, associate professor of computer science at California Institute of Technology, Hao Yan, professor of chemistry and biochemistry at Arizona State University and an expert in DNA nanotechnology and others.

The word ‘robot’ makes most people think of solid machines that use computer circuitry to perform defined jobs, such as vacuuming a carpet or welding together automobiles.

In recent years, scientists have worked to create robots that could also reliably perform useful tasks, but at a molecular level. This is, needless to say, not a simple endeavour, and it involves reprogramming DNA molecules to perform in specific ways.

“Can you instruct a biomolecule to move and function in a certain way? Researchers at the interface of computer science, chemistry, biology and engineering are attempting to do just that,” says Mitra Basu, programme director at National Science Foundation (NSF) responsible for the agency’s support to this research.

Recent molecular robotics work has produced so-called DNA walkers, or strings of reprogrammed DNA with ‘legs’ that enabled them to briefly walk.

Now this research team has shown these molecular robotic spiders can in fact move autonomously through a specially-created, two-dimensional landscape.

The spiders acted in rudimentary robotic ways, showing they are capable of starting motion, walking for awhile, turning and stopping.

Besides being incredibly small, about four nanometres in diameter, the walkers also move slowly, covering 100 nanometres in times ranging 30 minutes to a full hour by taking approximately 100 steps.

A nanometre is a billionth of a metre.

This is a significant improvement over previous DNA walkers that were capable of only about three steps, said a Columbia University release.

While the field of molecular robotics is still emerging, it is possible that these tiny creations may someday have important medical applications.

“This work one day may lead to effective control of chronic diseases such as diabetes or cancer,” Basu says.

These findings were outlined in the Thursday edition of Nature.