NSF-supported researchers expand storage capabilities of DNA

Major step toward integrating biological molecules into solid-state electronics

Moore's law has tracked the expansion of information technologies since the early 1970s. However, in recent years, the continued scaling of transistor structures has stalled, while computing and memory requirements have expanded exponentially. Due to its unique capabilities, DNA has the potential to serve as a high-density, low-energy-cost information storage system. However, traditional DNA data storage relies on sequencing, a slow, labor-intensive process not compatible with electronic devices.

Researchers at Arizona State University's Biodesign Institute and their collaborators have made a breakthrough in addressing this issue and taken a step that could enable DNA to serve as a building block for next-generation electronics. In a new study, a team demonstrated that by precisely controlling how metal ions bind within a DNA molecule, DNA can function as a fully electronic, chip-integrated memory system that is directly compatible with conventional electronics.

The system works by exploiting a small defect in the DNA strand that acts as a binding site for specific metal ions. By inserting silver and mercury between bases in the DNA strand, the researchers created a memory system capable of the same functions as a typical electronic storage device.

Depending on the pH and the applied electrical voltage, different ions bind to the molecule, changing its electrical resistance and effectively toggling between three distinct states: +1, 0 and -1. This means a single DNA molecule could store more than one bit of information, unlike normal transistors that only switch between 0 and 1.

Carbon nanotubes were used as ultra-small electrodes to hold individual DNA molecules in place, allowing them to operate for hours or even days without degradation. The team demonstrated that the states can be electrically cycled 48 times and that each state can be read over hundreds of cycles without failures.

The project was funded by the U.S. National Science Foundation Growing Convergence Research program, which brings together scientists from different disciplines to tackle complex problems. Chemists, nanotechnologists and electronic engineers joined forces under grants from the NSF directorates for Mathematical and Physical Sciences, Engineering and the Office of Integrative Activities.

Being able to electronically control chemical reactions at the single-molecule level could also transform how researchers design nanoscale materials and smart systems. The concept has potential in areas such as organic chemistry, drug discovery and other areas.