World-first unpowered DNA computer sets speed record

Computing is a power-hungry resource in today’s world. By 2050, as much as 20% of the electricity consumed by the US commercial sector will be used to crunch numbers. Data centers alone will double their electricity demand within the next few years, making the need for more efficient systems a high priority.Our own bodies seem like a strange place to look for a solution, but nature has had billions of years to find ways to do a lot with very little. Which is why researchers from Maynooth University in Ireland have turned to the very chemistry of life to develop a novel kind of computer that runs without a constant supply of electricity.“Silicon-based computers use so much energy – 23% of Ireland’s electricity goes into computing and data storage,” says computer scientist and senior author Damien Woods. “We’ve been blinkered by only seeing one type of computer, but there are other examples around us, including our brain.”Virtually all computers we use today rely on switches called transistors, which encode data in the form of on and off states. Manipulating these states to carry out even the simplest of calculations requires a tiny electrical charge.As small as this current might be, it quickly adds up as countless transistors switch states billions of times per second.The four chemical units that make up strands of DNA also encode information that can serve as the basis of algorithmic calculations. Instead of switches, the act of computing takes the form of a competition between various sequences.DNA computing itself is nothing new. In the 1990s, University of Southern California computer scientist Leonard Adleman solved the famous traveling salesman problem using nothing more than strings of nucleotides and biochemistry. Ever since, researchers have found novel ways to program their chemical recipes to meet a range of computational needs.One remaining challenge is to make a DNA computer that is energetically favorable, stable, reliable, and doesn’t require intervening tweaks and top-ups to arrive at a result.Woods' team considered a slightly different approach, one that has more to do with the emerging science of DNA origami than it does the old-fashioned competition between simple strands.The process combines a nucleic acid “scaffold” with short segments of DNA in a warm saline solution. As the mixture cools, the lowest energy configuration appears, providing an answer to the problem.“The molecules interact, form a structure, and that structure is the answer,” says Woods. “One key innovation is that the system naturally finds that answer without needing continuous energy inputs.”To test their method, the team ran a handful of different programs, some involving calculations up to 100 bits in size.One of the fastest calculations – adding three and 10 – still took around 30 seconds. Hardly blinding by any means, crunching math slower than a grade school student on a hot Friday afternoon.But that also isn’t the point. DNA computing runs in parallel, cramming a high number of computations into a single drop.“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,” says the study’s joint first author, Abeer Eshra.Beyond calculations, DNA has a remarkable ability to reliably store huge amounts of data in a robust bank. A single gram can – in theory – hold hundreds of millions of gigabytes, allowing us to cram the growing library of data accumulating each year into your garage (with room to spare).Coupled with low-energy methods for storing and retrieving this data, and thermodynamically favorable ways of running specialized calculations, the future of computing is starting to look pleasantly cold and wet.This research was published in Nature.Source: Maynooth University