MIT researchers invented a method of shrinking objects to the nanoscale.
The team can generate structures one-thousandth the volume of the original using a variety of materials, including metals, quantum dots, and DNA.
Existing techniques—like etching patterns onto a surface with light—work for 2D nanostructures, but not 3D. And while it’s possible to make 3D nanostructures, the process is slow, challenging, and restrictive.
So MIT professor Edward Boyden came up with a solution: By reversing a process for imaging brain tissue, he was able to pare down a relatively large object into something one-thousandth its original size—a process called “implosion fabrication.”
Using equipment many biology and materials science labs already have, researchers started by creating a scaffold out of polyacrylate (commonly found in diapers). They then soaked the frame in a solution of fluorescein molecules, which attach when activated by laser light.
“It’s a bit like film photography, according to co-author Daniel Oran, an MIT graduate student.
“A latent image is formed by exposing a sensitive material in a gel to light. Then, you can develop that latent image into a real image by attaching another material, silver, afterwards,” he explained. “In this way implosion fabrication can create all sorts of structures, including gradients, unconnected structures, and multi-material patterns.”
Once everything is in place, researchers douse the object with an acid, blocking negative charges in the polyacrylate, and forcing it to shrink.
“People have been trying to invent better equipment to make smaller nanomaterials for years, but we realized that if you just use existing systems and embed your materials in this gel, you can shrink them down to the nanoscale, without distorting the patterns,” co-author and grad student Samuel Rodriques, said in a statement.
The system, however, is not perfect.