|Image Credit: Illustration by Abigail Malate, American Institute of Physics|
Conventional nanostructure manufacturing techniques—ones that involve direct assembly or 3D printing—are directly limited by the precision of the machines. The new technique gets around this limitation by first creating a bigger structure inside of a gel, then shrinking the gel, which brings the structure down to one-thousandth the volume of the original.
This technique probably sounds familiar if you have ever played with Shrinky Dinks, the plastic sheets you can color and then shrink in the oven. Similar to how one can more easily fit many details in Shrinky Dink drawings before they are miniaturized, the researchers were able to more easily create delicate nanostructures by making much larger versions first. They built the structures inside of polyacrylate—a gel commonly found in diapers—and then used an acid to chemically shrink the whole thing to one-tenth of its original length in each of the three dimensions.
It is a reversed version of a recently developed technique known as expansion microscopy, in which biological samples are embedded in a gel that is then expanded, allowing researchers to discern details that were previously too small to be seen.
To test their methods, the researchers created silver wires, which retained their shape after shrinking. They also created another design that used the shrinking process itself to assemble a more complex structure. According to the researchers, the technique could be used to build nanostructures out of virtually anything, even “a piece of DNA.” They published their findings online Thursday in the journal Science.
—Yuen Yiu, Inside Science