This Silicon Chip Grows DNA in Plain Water. It Could Rewrite How the World Stores Data.

3 min readHere’s what you’ll learn when you read this story:Creating synthetic DNA is essential for developing vaccines, advancing gene therapy, and building out biotechnologies like DNA storage, but the process is complicated and chemically intensive. A new study developed a method for developing 64 different DNA sequences in parallel using a silicon chip, finely-tuned electrodes, and a water-based process known as enzymatic DNA synthesis.Although it’s eco-friendly and a huge leap forward compared to previous enzymatic attempts, the technology still has a long way to go to reach the scale necessary for our modern medical needs.DNA—that all-important collection of nucleotides—is the blueprint for life as we know it, and scientists’ ability to replicate this immense power of nature has provided incredible breakthroughs in vaccines, gene therapy, cancer research, and other biotechnology applications, including DNA data storage. But while synthetic DNA plays a vital role in modern medicine, actually creating those crucial double helixes is far from simple.Today’s synthesis of DNA requires a process known as phosphoramidite chemistry that relies on hazardous solvents and specialized facilities, which can be inaccessible for some laboratories that lack the resources. Now, a new study published in the journal Nature Electronics and led by scientists at Harvard showcases a new method for synthesizing DNA that uses revolutionary tools. This new process relies on a gentler, more eco-friendly method of synthesis known as “enzymatic DNA synthesis” and primarily uses water instead of chemicals, mimicking more closely how living cells build DNA.Using a silicon chip capable of controlling electric currents across specific locations, the scientists successfully manufactured 64 different DNA sequences (complete with 39 nucleotides each) at the same time. This far exceeds previous enzymatic DNA synthesis approaches that could only reproduce a dozen sequences or so, and pushes the technology toward being a true alternative to phosphoramidite chemistry.“DNA data storage asks DNA synthesis to operate at a scale far beyond today’s needs,” Pohang University’s Woo-Bin Jung, a co-author of the study, said in a press statement. “That is why enzymatic synthesis in water can matter. If far more than 64 sequences can be synthesized in parallel, it could offer an environmentally friendly route toward writing DNA at a very large scale.”Initially, the chip wasn’t designed as a DNA-making machine. Instead, a Ph.D student in the Harvard lab of Donhee Ham—who is a senior author of the study—initially developed the chip to record electrical activity in a group of neurons. However, after redesigning some of the surface electrodes, the chip’s precise electrical control could also be used to corral the exact chemical conditions needed to reproduce DNA.“A defining feature of the chip was precision current injection, which we used to permeabilize neuronal membranes for intracellular access,” Ham said in a press statement. “At a certain point, we wondered whether that same current control could be redirected from cells to molecules, replacing the neuron-facing electrodes with ring-electrode pairs that could localize pH for DNA synthesis. It worked.”Of course, the use of DNA as a storage method requires a massive scaling of this technology, so naturally, the researchers wondered if they could place synthesis sites on the chip closer together and produce more DNA sequences simultaneously. The answer was both yes and no.The chip delivered on its promise of localized low pH, as Ham describes above, but the chemical process known as deprotection—which entails removal of temporary protective groups that shield reactive sites on nucleotides—faltered as intermediate molecules drifted to neighboring sites, reducing separation.“The limitation came from the deprotection chemistry, not from the silicon,” Harvard post-doctoral researcher Han Sae Jung, co-first author of the study, said in a press statement. “That leaves a clear next step for the field—develop a more direct acid-driven deprotection chemistry that can keep pace with the chip.”With synthetic DNA lying at the heart of many modern medical technologies, finding a way to create these important biotech tools sustainably is a dire necessity. With this new chip, scientists are one step closer to making that dream a reality.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.