DNA is pretty remarkable stuff. As well as forming the basis for basically all life as we know it, it can also be used to make computers.
For several years now, research teams around the globe have been building these DNA computers to solve simple tasks - calculating square roots, or playing tic-tac-toe, for example. In all these cases, the circuits built are digital - special circuitry is used to convert the information into a sequence of 0s and 1s.
Now, however, a team of biologists at Duke University has created an circuit out of DNA that's analogue - meaning that it doesn't require conversion. The group created strands of synthetic DNA that, when mixed together in a test tube, can add, subtract and multiply as they form and break bonds.
The process is pretty slow compared to a traditional silicon computer - it can take hours to get a result out. "We can do some limited computing, but we can't even begin to think of competing with modern-day PCs or other conventional computing devices," said John Reif, who led the team.
But analogue DNA circuits can be way smaller than their silicon equivalent, and they also work in wet conditions. That means computing could take place in your bloodstream, or inside a cell. Plus, an analogue circuit uses fewer strands of DNA than digital ones do.
All this adds up to a system that could one day be able to operate within your body, keeping track of vital signs and taking measurements to diagnose or treat diseases. It could even detect the molecular signatures of particular types of cancer cells, and release substances that fight them.
"Even very simple DNA computing could still have huge impacts in medicine or science," Reif said.
The team's findings were published in the journal Synthetic Biology.