Maynooth Team Builds DNA Computer That Multiplies, Divides and Adds

Researchers at Maynooth University have built a DNA-based computer capable of multiplication, division, and addition, and has been described as one of the most complex and fastest molecular computers reported to date. The new molecular computer, described in Nature, uses interacting strands of DNA suspended in water rather than silicon chips, and needs no continuous electricity supply, only a small amount of heat to start the computation running.

The system points toward several future uses, including long-term data storage, more energy-efficient computation, and eventually molecular systems that could work inside living cells for purposes such as disease detection.

Damien Woods, who led the research, framed the appeal of moving beyond conventional hardware in terms of energy use: “Silicon-based computers use so much energy – 23% of Ireland’s electricity goes into computing and data storage. We’ve been blinkered by only seeing one type of computer, but there are other examples around us, including our brain.” Co-author Abeer Eshra, who carried out many of the experiments, explained how the scale of the reaction makes this possible: “A small droplet of liquid contains billions, and sometimes trillions, of DNA strands. These strands interact with one another to produce a result.”

To build the computer, the team combined a small drop of water and salt with short pieces of DNA and a longer DNA scaffold inside a test tube. Heating and then cooling this mixture allows the DNA to carry out a computation. “The molecules interact, form a structure and that structure is the answer,” Professor Woods said, adding: “One key innovation is that the system naturally finds that answer without needing continuous energy inputs.” 

The team ran ten programs on the system, including calculations involving 100 bits of information. Adding numbers in the range of roughly 11 million to 34 million took up to 14 hours to produce a result, while a simpler calculation, 10 plus 3, was completed in 30 seconds. The system also proved reusable, carrying out up to 25 different calculations in a row. As Dr. Eshra put it: “The reaction happens fast in the test tube, but not as fast as silicon, nor is it intended to be. But compared to other DNA computers, ours is the fastest.”

Professor Woods described the project as part of a wider search for alternative forms of computing, rather than a fixed roadmap: “This is blue skies science. We don’t know where the future is going to take us.”