Tag Archives: electronic memory

Nucleic acid-based memory storage

We’re running out of memory. To be more specific, there are two problems: the supply of silicon and a limit to how much silicon-based memory can store. An April 27, 2016 news item on Nanowerk announces a nucleic acid-based approach to solving the memory problem,

A group of Boise State [Boise State University in Idaho, US] researchers, led by associate professor of materials science and engineering and associate dean of the College of Innovation and Design Will Hughes, is working toward a better way to store digital information using nucleic acid memory (NAM).

An April 25, 2016 Boise State University news release, which originated the news item, expands on the theme of computer memory and provides more details about the approach,

It’s no secret that as a society we generate vast amounts of data each year. So much so that the 30 billion watts of electricity used annually by server farms today is roughly equivalent to the output of 30 nuclear power plants.

And the demand keeps growing. The global flash memory market is predicted to reach $30.2 billion this year, potentially growing to $80.3 billion by 2025. Experts estimate that by 2040, the demand for global memory will exceed the projected supply of silicon (the raw material used to store flash memory). Furthermore, electronic memory is rapidly approaching its fundamental size limits because of the difficulty in storing electrons in small dimensions.

Hughes, with post-doctoral researcher Reza Zadegan and colleagues Victor Zhirnov (Semiconductor Research Corporation), Gurtej Sandhun (Micron Technology Inc.) and George Church (Harvard University), is looking to DNA molecules to solve the problem. Nucleic acid — the “NA” in “DNA” — far surpasses electronic memory in retention time, according to the researchers, while also providing greater information density and energy of operation.

Their conclusions are outlined in an invited commentary in the prestigious journal Nature Materials published earlier this month.

“DNA is the data storage material of life in general,” said Hughes. “Because of its physical and chemical properties, it also may become the data storage material of our lives.” It may sound like science fiction, but Hughes will participate in an invitation-only workshop this month at the Intelligence Advanced Research Projects Activity (IARPA) Agency to envision a portable DNA hard drive that would have 500 Terabytes of searchable data – that’s about the the size of the Library of Congress Web Archive.

“When information bits are encoded into polymer strings, researchers and manufacturers can manage and manipulate physical, chemical and biological information with standard molecular biology techniques,” the paper [in Nature Materials?] states.

Cost-competitive technologies to read and write DNA could lead to real-world applications ranging from artificial chromosomes, digital hard drives and information-management systems, to a platform for watermarking and tracking genetic content or next-generation encryption tools that necessitate physical rather than electronic embodiment.

Here’s how it works. Current binary code uses 0’s and 1’s to represent bits of information. A computer program then accesses a specific decoder to turn the numbers back into usable data. With nucleic acid memory, 0’s and 1’s are replaced with the nucleotides A, T, C and G. Known as monomers, they are covalently bonded to form longer polymer chains, also known as information strings.

Because of DNA’s superior ability to store data, DNA can contain all the information in the world in a small box measuring 10 x 10 x 10 centimeters cubed. NAM could thus be used as a sustainable time capsule for massive, scientific, financial, governmental, historical, genealogical, personal and genetic records.

Better yet, DNA can store digital information for a very long time – thousands to millions of years. Currently, usable information has been extracted from DNA in bones that are 700,000 years old, making nucleic acid memory a promising archival material. And nucleic acid memory uses 100 million times less energy than storing data electronically in flash, and the data can live on for generations.

At Boise State, Hughes and Zadegan are examining DNA’s stability under extreme conditions. DNA strands are subjected to temperatures varying from negative 20 degrees Celsius to 100 degrees Celsius, and to a variety of UV exposures to see if they can still retain their information. What they’re finding is that much less information is lost with NAM than with the current state of the industry.

Here’s a link to and a citation for the Nature Materials paper,

Nucleic acid memory by Victor Zhirnov, Reza M. Zadegan, Gurtej S. Sandhu, George M. Church, & William L. Hughes. Nature Materials 15, 366–370 (2016)  doi:10.1038/nmat4594 Published online 23 March 2016

This paper is behind a paywall.

Love, hate, and the whole damn thing affect batteries, semiconductors, and electronic memory

A Jan. 24, 2013 news item on ScienceDaily features love triumphing over hate where tetracationic rings are concerned,

Northwestern University graduate student Jonathan Barnes had a hunch for creating an exotic new chemical compound, and his idea that the force of love is stronger than hate proved correct. He and his colleagues are the first to permanently interlock two identical tetracationic rings that normally are repelled by each other. Many experts had said it couldn’t be done.

On the surface, the rings hate each other because each carries four positive charges (making them tetracationic). But Barnes discovered by introducing radicals (unpaired electrons) onto the scene, the researchers could create a love-hate relationship in which love triumphs.

The Jan. 24, 2013 Northwestern University news release by Megan Fellman, which originated the news item, probes into the nature of the problem and its solution (Note: A link has been removed),

Unpaired electrons want to pair up and be stable, and it turns out the attraction of one ring’s single electrons to the other ring’s single electrons is stronger than the repelling forces.

The process links the rings not by a chemical bond but by a mechanical bond, which, once in place, cannot easily be torn asunder.

The study detailing this new class of stable organic radicals will be published Jan. 25 [2013] by the journal Science.

“It’s not that people have tried and failed to put these two rings together — they just didn’t think it was possible,” said Sir Fraser Stoddart, a senior author of the paper. “Now this molecule has been made. I cannot overemphasize Jonathan’s achievement — it is really outside the box. Now we are excited to see where this new chemistry leads us.”

The rings repel each other like the positive poles of two magnets. Barnes saw an opportunity where he thought he could tweak the chemistry by using radicals to overcome the hate between the two rings.

“We made these rings communicate and love each other under certain conditions, and once they were mechanically interlocked, the bond could not be broken,” Barnes said.

Barnes’ first strategy — adding electrons to temporarily reduce the charge and bring the two rings together — worked the first time he tried it. He, Stoddart and their colleagues started with a full ring and a half ring that they then closed up around the first ring (using some simple chemistry), creating the mechanical bond.

When the compound is oxidized and electrons lost, the strong positive forces come roaring back — “It’s hate on all the time,” Barnes said — but then it is too late for the rings to be parted. “That’s the beauty of this system,” he added.

Most organic radicals possess short lifetimes, but this unusual radical compound is stable in air and water. The compound tucks the electrons away inside the structure so they can’t react with anything in the environment. The tight mechanical bond endures despite the unfavorable electrostatic interactions.

The two interlocked rings house an immense amount of charge in a mere cubic nanometer of space. The compound, a homo[2]catenane, can adopt one of six oxidation states and can accept up to eight electrons in total.

“Anything that accepts this many electrons has possibilities for batteries,” Barnes said.

“Applications beckon,” Stoddart agreed. “Now we need to spend more time with materials scientists and people who make devices to see how this amazing compound can be used.”

For anyone interested in the details of the work, here’s a citation and link to the paper published in Science,

A Radically Configurable Six-State Compound by Jonathan C. Barnes, Albert C. Fahrenbach, Dennis Cao, Scott M. Dyar, Marco Frasconi, Marc A. Giesener, Diego Benítez, Ekaterina Tkatchouk, Oleksandr Chernyashevskyy, Weon Ho Shin, Hao Li, Srinivasan Sampath, Charlotte L. Stern, Amy A. Sarjeant, Karel J. Hartlieb, Zhichang Liu, Raanan Carmieli, Youssry Y. Botros, Jang Wook Choi, Alexandra M. Z. Slawin, John B. Ketterson, Michael R. Wasielewski, William A. Goddard III, J. Fraser Stoddart. Science 25 January 2013: Vol. 339 no. 6118 pp. 429-433 DOI: 10.1126/science.1228429

This is paper is behind a paywall.