The researchers used a technique known as ‘implosion fabrication’ to shrink objects to nanoscale. (Image credit: MIT)
Researchers from MIT have developed a way to shrink complex 3D objects down to nanoscale sizes using hydrogel and a laser. Using a new technique known as ‘implosion fabrication,’ the researchers are able to create any 3D structure they want by using a laser to pattern a polymer scaffold. They can then attach hydrogel to the structure to shrink it down one-thousandth of its original size. Potential applications for this new technique include medicine, robotics, and optics, to name just a few.
Current fabrication techniques for creating nanostructures are limited in what can be accomplished. It’s possible to make 3D nano-objects by adding layers on top of one another, similar to 3D printing, however, it’s time-consuming and inefficient. Utilizing 3D printing outright limits what materials can be used- such as polymers and plastics, and even then, they can only generate self-supporting structures like solid pyramids or cubes, rather than hollow objects or complex shapes.
To get around those issues, the researchers decided to use a different fabrication method known as expansion microscopy- a process where a polymer network is introduced into tissue (or cellular) sample and then expanding it through chemical reactions, which makes them larger. Of course, they reversed this method by embedding an object within expanded hydrogels, then subjecting it to a laser, thus shrinking the hydrogel and the object within. Specifically, the researchers used a material made of polyacrylate as the scaffold, which is bathed in a solution containing fluorescein molecules that attach to the framework when hit with laser light.
To precisely target points deep within a structure, the researchers used two-photon microscopy to connect those fluorescein molecules at certain locations within the gel, which act as anchors for any number of materials.
According to MIT Professor of Neurotechnology Edward Boyden- “You attach the anchors where you want with light, and later you can attach whatever you want to the anchors. It could be a quantum dot, it could be a piece of DNA, it could be a gold nanoparticle.” He goes on to state, “There are all kinds of things you can do with this. Democratizing nanofabrication could open up frontiers we can’t yet imagine.”
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