Science & Technology, (Commonwealth Union) – Taking inspiration from the “Jurassic Park,” movie which saw use of DNA stored in amber to create dinosaurs, MIT researchers have created a glassy, amber-like polymer designed for the long-term storage of DNA, whether it be entire human genomes or digital files like photos.
Current DNA storage methods typically need freezing temperatures, which consume a significant amount of energy and are impractical in many regions. Unlike these methods, the new amber-like polymer can preserve DNA at room temperature, shielding the molecules from heat and water damage.
The researchers showed that this polymer could retain DNA sequences encoding the Jurassic Park theme music as well as an entire human genome. They also proved that the DNA could be easily extracted from the polymer without any harm.
James Banal, a former MIT postdoc indicated that freezing DNA is currently the primary preservation method, however it is costly and not scalable. He added that their new preservation technique could be a breakthrough technology for future digital information storage on DNA.
James Banal and Jeremiah Johnson, the A. Thomas Geurtin Professor of Chemistry at MIT, are the senior authors of this study, which was published recently in the Journal of the American Chemical Society. The lead authors are former MIT postdoc Elizabeth Prince and MIT postdoc Ho Fung Cheng.
Researchers of the study pointed out that DNA, a highly stable molecule, is ideal for storing vast amounts of information, including digital data. Digital storage systems represent text, images, and other information as sequences of 0s and 1s. This same information can be encoded in DNA using the four nucleotides that form the genetic code: A, T, G, and C. For instance, G and C could be used to signify 0, while A and T could represent 1.
They also pointed out that DNA provides a method for storing digital information at an extremely high density: in theory, a coffee cup filled with DNA could hold all the world’s data. Additionally, DNA is very stable and relatively simple to synthesize and sequence.
In 2021, Banal and his postdoctoral advisor, Mark Bathe, a professor of biological engineering at MIT, developed a method that could retain DNA in silica particles, which could be tagged to reveal the particles’ contents. This work led to the creation of a spinout company named Cache DNA.
One drawback of that storage system is that it takes many days to embed DNA into the silica particles. Moreover, extracting the DNA from the particles has the need for hydrofluoric acid, which can be dangerous for workers that handle the DNA.
To find alternative storage materials, Banal began collaborating with Johnson and his lab members. Their concept was to use a type of polymer known as a degradable thermoset, which consists of polymers that form a solid when heated. This material also consists of cleavable links that can be easily broken, this permits the polymer to degrade in a controlled manner.
“With these deconstructable thermosets, depending on what cleavable bonds we put into them, we can choose how we want to degrade them,” explained Johnson.
For this project, the researchers opted to create their thermoset polymer using styrene and a cross-linker. These components bring about that creation of an amber-like thermoset known as cross-linked polystyrene. This thermoset is highly hydrophobic, which helps to prevent moisture from penetrating and damaging the DNA. To make the thermoset degradable, the styrene monomers and cross-linkers are copolymerized with monomers called thionolactones, which can be broken down by treating them with a molecule called cysteamine.
Due to styrene’s hydrophobic nature, the researchers had to devise a method to incorporate DNA, a hydrophilic and negatively charged molecule, into the styrene.
They identified a combination of three monomers that could be polymerized to facilitate the interaction of DNA with styrene. Each monomer possesses unique properties that work together to extract the DNA from water and introduce it into the styrene. In this environment, the DNA forms spherical complexes, with the charged DNA at the center and hydrophobic groups forming an outer layer that interacts with the styrene. Upon heating, this solution solidifies into a glass-like block containing embedded DNA complexes.
“The idea is, why don’t we preserve the master record of life forever?” said Banal.
