By Josh Perry, Editor
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Researchers at the Massachusetts Institute of Technology (MIT) in Cambridge, Mass. have not yet developed the suit worn in the Ant-Man movies, but they have created a fabrication technique that can precisely build any 3-D structure in a nanoscale version.

MIT engineers have devised a way to create 3-D nanoscale objects by patterning a larger structure with a laser and then shrinking it. (Daniel Oran/MIT)

According to a report from the school, the scientists have worked with a variety of materials, including metals, quantum dots, and DNA. They use a laser to pattern a polymer scaffold and attach the materials that they want before shrinking it to one thousandth of the volume of the original.

The researchers reversed the process of expansion microscopy, which was being used for high-resolution 3-D visualization of cells and tissues, and developed implosion fabrication.

“As they did for expansion microscopy, the researchers used a very absorbent material made of polyacrylate, commonly found in diapers, as the scaffold for their nanofabrication process,” the article explained. “The scaffold is bathed in a solution that contains molecules of fluorescein, which attach to the scaffold when they are activated by laser light.”

The fluorescein molecules are attached at specific points in the scaffold through two-photon microscopy. The molecules act as anchors for the other materials being added. The structure is shrunk by adding acid, which causes the polyacrylate gel to contract as much as 10-fold in each direction.

“This ability to shrink not only allows for increased resolution, but also makes it possible to assemble materials in a low-density scaffold,” the article said. “This enables easy access for modification, and later the material becomes a dense solid when it is shrunk.”

Currently, researchers can create objects around 1 cubic millimeter and a resolution of 50 nanometers. They are working on improving resolution by refining the process.

The research was recently published in Science. The abstract read:

“Lithographic nanofabrication is often limited to successive fabrication of two-dimensional (2D) layers. We present a strategy for the direct assembly of 3D nanomaterials consisting of metals, semiconductors, and biomolecules arranged in virtually any 3D geometry.

“We used hydrogels as scaffolds for volumetric deposition of materials at defined points in space. We then optically patterned these scaffolds in three dimensions, attached one or more functional materials, and then shrank and dehydrated them in a controlled way to achieve nanoscale feature sizes in a solid substrate.

“We demonstrate that our process, Implosion Fabrication (ImpFab), can directly write highly conductive, 3D silver nanostructures within an acrylic scaffold via volumetric silver deposition. Using ImpFab, we achieve resolutions in the tens of nanometers and complex, non–self-supporting 3D geometries of interest for optical metamaterials.”