Scientists Just Built a Computer Out of DNA—and It Runs Without Electricity

3 min readHere’s what you’ll learn when you read this story:• While DNA computers aren’t as fast as traditional silicon-based machines, they have multiple advantages in terms of energy efficiency, storage, and parallel processing.• A new study developed a DNA computer that uses the principle of “energetically favorable” states to perform calculations using just a little bit of heat.• In a single droplet of water, trillions of short DNA strands attach to a longer DNA scaffold, and the shape they form is the answer.The history of computing showcases incredible machines that come in all shapes and sizes. The Harvard Mark I, one of the earliest protocomputers built during World War II, weighed roughly five tons and contained 750,000 separate parts. In 2015, the University of Michigan revealed the “Micro Mote,” a one-millimeter-sized computer. Even the basic components that make up computers show a stunning amount of diversity.While most traditional computers today rely on silicon and transistors (so long, vacuum tubes), DNA computers take advantage of the very building blocks of life to make calculations. Now, a team of researchers at Maynooth University (MU) in Ireland has developed one of the fastest DNA computers to date. As they report in a new study published in the journal Nature, the machine uses billions or even trillions of DNA strands housed in a single drop of water.“The molecules interact, form a structure and that structure is the answer,” MU’s Damien Woods, senior author of the study, said in a press statement. “One key innovation is that the system naturally finds that answer without needing continuous energy inputs.”The ingredient list for this machine reads more like a biology experiment than an electronics catalog: water, salt, short DNA strands, and a longer DNA scaffold combine to form what’s called a Scaffolded DNA Computer (SDC). Instead of using continuous energy to perform a series of processing steps, the DNA computer relies on a nifty law of physics where the DNA strands react to form an “energetically favorable” state. The DNA scaffold acts as the computing substrate while shorter strands, or compute tiles, bind to the scaffold and eventually settle into a lowest-energy state with the fewest mismatched tiles, according to ZME Science.Testing their DNA computer across 700 calculations, ranging from simple multiplication to 8-bit parity detection, the scientists discovered that the system achieved a 95 percent success rate. Simple equations only took a couple dozen seconds to answer, while solving more complex problems could stretch out to several hours—but raw, single-operation speed isn’t a DNA computer’s strong suit.“The reaction happens fast in the test tube, but not as fast as silicon, nor is it intended to be,” MU’s Tristan Stérin, co-first author of the study, said in a press statement. “But compared to other DNA computers, ours is the fastest.”While DNA computers might never replace smartphones, laptops, and desktops that run our day-to-day lives, the platform holds huge advantages in terms of electrical usage, parallel processing, and storage. The new SDC requires only a little bit of heat to kick off calculations. And while individual DNA reactions are slow, parallelism makes greater speed possible at larger scales. Because trillions of strands can react simultaneously, DNA computers have long been projected to outpace conventional machines on highly parallel problems. A 2023 Nature study from Shanghai Jiao Tong University demonstrated DNA circuits supporting more than 100 billion unique configurations. DNA computers can also be data storage behemoths, since just one cubic centimeter of DNA can theoretically store a trillion CDs’ worth of information.For now, the new DNA computer shows that the basic building blocks of life have the capacity to redefine what computing can be.“This is blue skies science,” Woods said in a press statement. “We don’t know where the future is going to take us.”Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.