Advance in synthetic DNA production promises practical storage capability

A new advance in a method to synthetically produce DNA (deoxyribonucleic acid) brings us closer to using DNA to efficiently store the increasingly huge amount of information the world generates.

DNA, life's data storage system, has long been proposed as a potentially ideal archive for digital information because of its permanence and incredible density. But making it a practical alternative to data storage on chips, hard disks, or magnetic tape requires lowering the cost of producing synthetic DNA and reducing errors.

A team of researchers at the Harvard’s Wyss Institute for Biologically Inspired Engineering and Harvard Medical School has developed a way to synthesize DNA using enzymatic, instead of chemical, synthesis in a multiplexed (parallel production) manner. Their research was published on Oct. 16 in the journal Nature Communications.

The enzymatic synthesis method pioneered by the Wyss team to write DNA uses a special biological enzyme they developed, terminal deoxynucleotidyl transferase (TdT), combined with photolithography. Photolithography is a technique used in etching minute silicon chips by transferring a pattern from a mask or matrix to a photosensitive substrate material.

The Wyss team's innovative method uses pulsed ultraviolet light to control the activation and deactivation of cobalt ions in a fluid substrate containing TdT. Pulsing high energy photons allows TdT in the fluid substrate material to synthesize DNA in a controlled on/off manner. This enables the researchers to program the TdT to add one short strand of synthesized DNA code at a time.

Traditional coding uses a binary system, translating data into 0s and 1s. In a similar fashion, DNA coding uses the four DNA components A, C, G and T, and their transitions from one to another (such as A to C or G to T) to translate data into code.

This gives DNA the capability of encoding data in a form that is 1,000 times denser than today's most compact solid-state hard drive. The authors estimate that DNA can store "hundreds of petabytes per gram DNA." (1 petabyte equals 1 million gigabytes.)

Further, the Wyss Institute states, DNA storage is at least 300 times more durable than the best magnetic tapes. In addition, the coded DNA is easily reproducible in multiple copies.

The Wyss team tested their storage method using 12 DNA oligonucleotide sequences to store 110 bits of data of video game music.

One limitation is that DNA fragments produced using TdT are shorter than those created in the chemical synthesis method. The authors comment, however, that they believe using larger and denser arrays of their matrix pattern will allow them to scale up longer DNA oligonucleotide sequences with higher levels of multiplexing.

The Nature Communications paper concludes that although method limitations must be overcome: "Looking into the future, we believe that efforts to harness multiplexed enzymatic oligonucleotide synthesis in the context of important applications such as digital data storage will usher in a new era of scientific research and biotechnology."