Materials that are both strong and lightweight could improve everything from cars to body armor. The two qualities are usually mutually exclusive, though. Now, University of Connecticut researchers and colleagues from Columbia University and Brookhaven National Lab have developed an extraordinarily strong, lightweight material using unlikely building blocks: DNA and glass.
“For the given density, our material is the strongest known,” said UConn’s Seok-Woo Lee.
The team reports that by building a structure out of DNA and then coating it with glass, they have created a very strong material with very low density. Glass might seem a surprising choice, as it shatters easily. However, glass usually shatters because of a flaw — e.g., a crack, scratch, or missing atoms — in its structure. A flawless cubic centimeter of glass can withstand 10 tons of pressure.
It’s very difficult to create a large piece of glass without flaws. But the researchers knew how to make very small, flawless pieces. As long as glass is less than a micrometer thick, it’s almost always flawless. And since the density of glass is much lower than metals and ceramics, any structures made of flawless nano-sized glass should be strong and lightweight.
The team created a structure of self-assembling DNA. Almost like Magnatiles, pieces of DNA of specific lengths and chemistry snapped themselves together into a skeleton of the material. Imagine the frame of a house or building, but made of DNA.
They then coated the DNA with a very thin layer of glass-like material only a few hundred atoms thick. The glass only just coated the strands of DNA, leaving a large part of the material volume as empty space, much like the rooms within a house or building. The DNA skeleton reinforced the thin, flawless coating of glass making the material very strong, and the voids comprising most of the material’s volume made it lightweight.
As a result, glass nanolattice structures have four times higher strength but five times lower density than steel. “The ability to create designed 3D framework nanomaterials using DNA and mineralize them opens enormous opportunities for engineering mechanical properties. But much research work is still needed before we can employ it as a technology,” said Nanomaterials Scientist Oleg Gang.
The team is currently working with the same DNA structure but substituting even stronger carbide ceramics for glass. They have plans to experiment with different DNA structures to see which makes the material strongest. Future materials based on this same concept have great promise as energy-saving materials for vehicles and other devices that prioritize strength. Lee believes that DNA origami nanoarchitecture will open a new pathway to create lighter and stronger materials that we have never imagined before.
Here is an exclusive Tech Briefs interview — edited for length and clarity — with Lee.
Tech Briefs: Glass and DNA is an unusual combination. How did the pairing come about? What was the catalyst for your work?
Lee: My collaborators at Brookhaven National Lab are DNA experts. They developed the structure for another experiment; they are not interested in mechanical properties. Then one day we met — by chance — at Brookhaven National Lab, and I realized that they’re making an interesting DNA structure and they were able to coat with thin glass around the DNA. So, I immediately noticed that that must be great for mechanical property. Then I asked them to send me their sample, then we tested, and then we got an interesting mechanical behavior. So, we didn't have any hypothesis.
I’ve studied mechanical behavior of nanostructured material for more than 10 years. I knew that if you make anything very tiny — like a nanometer scale — the material becomes very strong. So, I knew that idea, and then by chance I met Brookhaven National Lab people who can make such a structure. Then we tested, and then we got the data.
Tech Briefs: What was the biggest technical challenge you faced throughout your work?
Lee: The material is very tiny. This is always the issue in nanotechnology. All these nanostructures have very good properties — the electronic property, mechanical property, optical properties. But they are all very tiny. So, it is a very good object for scientific study, but if you use it, you have to scale up. That is always the issue.
My collaborators use self-assembly techniques. Once you put the DNA into the water, then they self-assemble and become nice, beautiful structures. We think that it's partially successful because they can connect this nanoscale object, DNA, and then make micrometer scales.
But, if you really want to use this material for airplanes, buildings, or weapons, they must be at least a centimeter scale. So, it's very difficult to make steel a centimeter-scale size. Scaling up is the issue.
Tech Briefs: What are your next steps? Do you have any other future research on the horizon?
Lee: I’m looking for something similar. For example, this is the first paper and exploration. We confirmed that DNA nanostructures are very strong. The next step is scientific studies, two different ways: one is we can try to measure the mechanical property of different structures with the same material. Also, we can use the same structure with a different material. As I said, like glass and carbide and metal — you can see how they work. That is the DNA part.
And, also, I'm working with similar materials, what we call nanoporous material. And then recently we studied nanoporous carbon structure. It's classic carbon; it's more like a diamond — the carbon bonding is very strong bonding, but nanoporous. Then we found out the mechanical property is similar with this DNA structure. And that one is really good because we can build a centimeter-scale object.
Tech Briefs: Do you have any advice for researchers or engineers aiming to bring their ideas to fruition?
Lee: One of my recommendations is to scale up; scaling up is very important. A lot of the material scientists today are interested in science only. But if we really bring that science to technology, the scale up is very important. So, I think engineers and scientists should work together, and then just find the idea how to really use everything.