The key to making such tiny devices in large quantities lies in a method the team developed for controlling the natural fracturing process of atomically-thin, brittle materials, directing the fracture lines so that they produce miniscule pockets of a predictable size and shape. Embedded inside these pockets are electronic circuits and materials that can collect, record, and output data.
The novel process, called “autoperforation,” is described in a paper published today in the journal Nature Materials, by MIT Professor Michael Strano, postdoc Pingwei Liu, graduate student Albert Liu, and eight others at MIT.
The system uses a two-dimensional form of carbon called graphene, which forms the outer structure of the tiny syncells. One layer of the material is laid down on a surface, then tiny dots of a polymer material, containing the electronics for the devices, are deposited by a sophisticated laboratory version of an inkjet printer. Then, a second layer of graphene is laid on top.
People think of graphene, an ultrathin but extremely strong material, as being “floppy,” but it is actually brittle, Strano explains. But rather than considering that brittleness a problem, the team figured out that it could be used to their advantage.
“We discovered that you can use the brittleness,” says Strano, who is the Carbon P. Dubbs Professor of Chemical Engineering at MIT. “It’s counterintuitive. Before this work, if you told me you could fracture a material to control its shape at the nanoscale, I would have been incredulous.”
But the new system does just that. It controls the fracturing process so that rather than generating random shards of material, like the remains of a broken window, it produces pieces of uniform shape and size. “What we discovered is that you can impose a strain field to cause the fracture to be guided, and you can use that for controlled fabrication,” Strano says.
When the top layer of graphene is placed over the array of polymer dots, which form round pillar shapes, the places where the graphene drapes over the round edges of the pillars form lines of high strain in the material. As Albert Liu describes it, “imagine a tablecloth falling slowly down onto the surface of a circular table. One can very easily visualize the developing circular strain toward the table edges, and that’s very much analogous to what happens when a flat sheet of graphene folds around these printed polymer pillars.”
As a result, the fractures are concentrated right along those boundaries, Strano says. “And then something pretty amazing happens: The graphene will completely fracture, but the fracture will be guided around the periphery of the pillar.” The result is a neat, round piece of graphene that looks as if it had been cleanly cut out by a microscopic hole punch.
Because there are two layers of graphene, above and below the polymer pillars, the two resulting disks adhere at their edges to form something like a tiny pita bread pocket, with the polymer sealed inside. “And the advantage here is that this is essentially a single step,” in contrast to many complex clean-room steps needed by other processes to try to make microscopic robotic devices, Strano says.
The researchers have also shown that other two-dimensional materials in addition to graphene, such as molybdenum disulfide and hexagonal boronitride, work just as well.
Image Credit: YouTube/MIT
News This Week
From CIO Applications: Although nanotechnology is depicted as genuinely recent human development, nature is in reality loaded with nanoscopic designs. They support the fundamental elements of an assortment of living things, from microorganisms to [...]
NASA has certified SpaceX’s Falcon 9 to launch the agency’s most important science missions, giving the agency new options that could result in lower costs. SpaceX said that the NASA Launch Services Program (LSP) [...]
NASA signed an agreement in September with a foundation to support initial studies of a privately funded mission to a potentially habitable moon of Saturn. The unfunded Space Act Agreement between NASA and the [...]
A small clinical trial using gold nanoparticles that act as tumor-seeking missiles on a mission to remove prostate cancer has begun at The University of Texas Health Science Center at Houston (UTHealth). It [...]
A small clinical trial using gold nanoparticles that act as tumor-seeking missiles on a mission to remove prostate cancer has begun at The University of Texas Health Science Center at Houston (UTHealth). It is [...]
Nanomedical Device and Systems Design: Challenges, Possibilities, Visions now available to rent on Kindle
To accommodate students who wish to read the book at an affordable cost, Nanomedical Device and Systems Design: Challenges, Possibilities, Visions by Frank Boehm (CEO NanoApps Medical Inc.) is available to rent on Kindle. This book benefits [...]
Researchers at the Mount Sinai School of Medicine have developed a new nanotechnology-based immunotherapy that promotes long-term transplant acceptance in an animal model. The development, which is described in the journal Immunity, could transform [...]
“It’s a bit like driving past a vineyard and looking out the window at the vineyard rows. Every now and then, you see no rows because you’re looking directly along a row,” said Nathaniel [...]
The use of nanoparticles and other nanoscale materials has been gathering a lot of significant interest in recent years and has even adapted into its own interdisciplinary field of science known as nanomedicine. Whilst [...]
Immune Aspects of Biopharmaceuticals and Nanomedicines 1st Edition Raj Bawa, Janos Szebeni, Thomas J Webster, Gerald F. Audette The enormous advances in the immunology of biotherapeutics and nanomedicines in the past two decades have [...]
Immune Aspects of Biopharmaceuticals and Nanomedicines Available from CRC Press 1st Edition Raj Bawa, Janos Szebeni, Thomas J Webster, Gerald F. Audette The enormous advances in the immunology of biotherapeutics and nanomedicines in the [...]
Researchers of the “Micro, Nano and Molecular Systems” Lab at the Max Planck Institute for Intelligent Systems in Stuttgart, together with an international team of scientists, developed propeller-shaped nanorobots that, for the first time, [...]
Nanotechnology experts from around the world, who use innovation in materials science to create advanced technologies and solutions for the environment, energy, and health sectors, will congregate in Newcastle Australia for the third International [...]
Geckos and many other animals have heads that are too small to triangulate the location of noises the way we do, with widely spaced ears. Instead, they have a tiny tunnel through their heads [...]