Scientists turn DNA into a memory device that uses 100x less power

The challenge has been finding a way to make biological DNA function effectively alongside electronic materials. Penn State researchers have now developed an approach designed to overcome that incompatibility.

The work, published in Advanced Functional Materials and the subject of a patent application, relies on two key components. One is synthetic DNA, made from commercially available, chemically engineered molecules arranged into short genetic sequences tailored for specific electronic requirements. The other is crystalline perovskite, a semiconductor already used in technologies including solar cells, lasers and data storage devices.

"Biology and electronics are different domains," said Kavya S. Keremane, co-corresponding author and postdoctoral researcher in materials science and engineering at Penn State. "Bridging these two fields required developing an entirely new materials platform that allows them to function seamlessly together. By combining the information storage capabilities of DNA with the exceptional electronic properties of perovskite semiconductors, we created a bio-hybrid system that fundamentally changes how low-power memory devices can be designed."

Building a Low Power Memory Device

Using these materials, the team created a memory resistor, known as a "memristor," that operates with very little energy. Unlike ordinary resistors, which maintain a set resistance to electrical current in devices ranging from cell phones to space shuttles and lose their stored information when power disappears, memristors can preserve a record of previous electrical activity. They can remember the direction in which current previously flowed even after the power source is removed.

That ability allows information to be stored and processed in the same place, resembling the way neurons function in the brain. Such an arrangement could support more simultaneous and sophisticated forms of data processing. According to the researchers, however, practical commercial systems would still require enough storage capacity and electrical power to become costly and inefficient without DNA's ability to pack enormous amounts of information into a very small space while consuming little energy.

"As the demand for artificial intelligence (AI) grows, we need a new strategy for low-power, high-storage devices," said Bed Poudel, co-corresponding author and research professor of materials science and engineering at Penn State.

Poudel said AI and other emerging technologies are expected to depend increasingly on neuromorphic computing, which is designed to operate more like the human brain. Such systems can evaluate multiple inputs at once while making decisions informed by previous experiences and future priorities.

"Usually, it takes more power to store more information. Our device, however, consumes 100 times less power and the storage capacity is higher than traditional storage devices, like flash drives."

Engineering DNA to Conduct Electricity

To construct the device, the researchers added silver nanoparticles to a layer of customized DNA sequences -- specially designed to be of certain compositions and lengths -- that was integrated with thin films of perovskite.

This technique, called "doping," involves introducing a small amount of another material to produce specific properties. In this case, adding the silver nanoparticles allowed the DNA to conduct electricity while also helping its molecular units line up in a more orderly arrangement.

Synthetic DNA offered another important advantage over natural DNA. Unlike natural DNA -- long, entangled strands that behave like wet spaghetti when handled -- short and rigid pieces of synthetic DNA can be arranged with much greater precision at extremely small scales.

According to co-author Neela H. Yennawar, research professor and director of the Penn State Huck Institutes of the Life Sciences' Biomolecular Interactions Core Facility, molecularly engineered DNA can provide structural organization, adjustable electrical conductivity and functional control that natural DNA cannot achieve when incorporated into thin films.

"We can computationally determine exactly which sequences we need and how long they should be, and then we can rationally design them with synthetic DNA," Yennawar said. "These structures can be systematically doped with silver and other ions and engineered to interface seamlessly with perovskites -- transforming DNA from a biological macromolecule into a programmable, multifunctional nanomaterials platform."

DNA and Perovskite Work Better Together

When combined, the silver-doped DNA and perovskite formed bio-hybrid pathways that directed the flow of electrical current through the device.

The researchers found that electrons moved reliably when they applied less than 0.1 volt -- for comparison, standard U.S. outlets have 120 volts -- and the device responded predictably when the direction of the current was changed.

The carefully designed DNA structures, combined with the perovskite, also helped make the device unusually stable. According to the team, it continued operating consistently at temperatures approaching 250 degrees Fahrenheit and remained functional at room temperature for more than six weeks, substantially exceeding the performance standards of existing perovskite-based memory storage devices.

The researchers also reported that the new system could perform the same memory function as comparable technologies while consuming only one-tenth as much power. That level of efficiency could make the approach especially attractive for future electronics designed to handle large amounts of information with lower energy demands.

"Using just the DNA or just perovskite alone did not produce near as robust a result as the combination," Keremane said. "It's this combination that enables a very high memory storage density that requires very little power."

A New Direction for Bio-Inspired Electronics

The team now plans to improve the technology further and explore additional uses for bio-inspired electronic systems.

"Nature has the solution -- we just have to find it and apply it," Poudel said. "This work of integrating DNA into electronics to do amazing things gives a glimpse into what is possible."

In addition to Keremane, Yennawar and Poudel, other Penn State co-authors include co-corresponding author Luyao Zheng, postdoctoral research in materials science and engineering; Haodong Wu, doctoral student in materials science and engineering; Jiamao Zheng, who was a master's student in materials science and engineering at the time of research and has since graduated from Penn State; Shashank Priya, who was a professor of materials science and engineering at the time of research; and Chiranth C. Ravi, who was a master's student in the Huck Institutes of the Life Sciences at the time of research and has since graduated from Penn State. Abhinav Gorthy and co-corresponding author Rashmi Jha, chemical engineering and materials science, University of Minnesota, also contributed.

The U.S. National Science Foundation, the National Institutes of Health, Penn State and the University of Minnesota supported this research.