It's not quite the Ant-Man suit, but researchers have invented a way to shrink 3D objects of nearly any shape down to the nanoscale. They can also pattern the objects with a variety of useful materials, including metals, quantum dots, and DNA.
"It's a way of putting nearly any kind of material into a 3D pattern with nanoscale precision," says Edward Boyden, senior author of the research and associate professor of biological engineering and of brain and cognitive sciences at MIT.
Using the new technique, the researchers can create any shape and structure they want by patterning a polymer scaffold with a laser. After attaching other useful materials to the scaffold, they shrink it, generating structures one thousandth the volume of the original.
These tiny structures could have applications in many fields, from optics to medicine to robotics, the researchers say. The technique uses equipment that many biology and materials science labs already have, making it widely accessible for researchers who want to try it.
"There are all kinds of things you can do with this," Boyden says. "Democratizing nanofabrication could open up frontiers we can't yet imagine."
Existing techniques for creating nanostructures are limited in what they can accomplish. Etching patterns onto a surface with light can produce 2D nanostructures but doesn't work for 3D structures. It is possible to make 3D nanostructures by gradually adding layers on top of each other, but this process is slow and challenging. And, while methods exist that can directly 3D print nanoscale objects, they are restricted to specialized materials like polymers and plastics, which lack the functional properties necessary for many applications. Furthermore, they can only generate self-supporting structures. (The technique can yield a solid pyramid, for example, but not a linked chain or a hollow sphere.)
To overcome these limitations, Boyden and his students decided to adapt a technique that his lab developed a few years ago for high-resolution imaging of brain tissue. This technique, known as expansion microscopy, involves embedding tissue into a hydrogel and then expanding it, allowing for high resolution imaging with a regular microscope. Hundreds of research groups in biology and medicine are now using expansion microscopy, since it enables 3D visualization of cells and tissues with ordinary hardware.