Press Releases: Research Funded by Agencies Participating in the National Nanotechnology Initiative

Kombucha tea, a trendy fermented beverage, has inspired engineers at the U.S. Army's Institute for Soldier Nanotechnologies at MIT and Imperial College London to develop a new way to generate tough, functional materials with a mixture of bacteria and yeast similar to the kombucha mother used to ferment tea. These functional materials, which consist of a dense network of ribbon-like cellulose fibrils, each about 50 nanometers wide and up to 9 micrometers in length, can perform a variety of functions, such as sensing environmental pollutants, purifying water for soldiers in the field, and making smart packaging materials that can detect damage.

Two studies from researchers at Yale University answer some key questions about two-dimensional (2-D) materials. In one study, the researchers experimentally measured the precise doping effects of small molecules on 2-D materials—a first step toward tailoring molecules for modulating the electrical properties of 2-D materials. In the second study, the researchers looked at the effects of mechanical strain on the ordering of lithium in lithium-ion batteries and demonstrated how much the lithium atoms slow down.

Researchers at MIT and the U.S. Department of Energy’s Argonne National Laboratory have designed a new class of small molecules that spontaneously assemble into nanoribbons with unprecedented strength, retaining their structure outside of water. For the past couple of decades, scientists and engineers have been designing molecules that assemble themselves in water, with the goal of making nanostructures, primarily for biomedical applications such as drug delivery or tissue engineering. But these structures fall apart in the absence of water. These small molecules, however, retain their structure outside of water, which could inspire a broad range of applications.

Researchers from New York University, the College of Staten Island, and the U.S. Department of Energy’s Sandia National Laboratories have revealed how room-temperature phase transitions occur between atomically thin, 2-D hexagonal-phase boron nitride and cubic-phase boron nitride. The work involved application of pressure to atomically thin films of hexagonal-phase boron nitride with a number of atomic layers (from one to ten) by using an atomic force microscope (AFM). To test the extent of the phase transition from hexagonal to cubic crystalline structure, the AFM nanoscopic tip probe simultaneously applied pressure and measured the material’s elasticity.

Researchers at Washington University in St. Louis have developed a microneedle patch that can help detect small amounts of antibodies in interstitial fluid. The researchers used fluorescence nanolabels to detect protein biomarkers present in small amounts in interstitial fluid. The signal from the target biomarkers in samples was approximately 1,400 times brighter than that from conventional fluorescent labels.

By embedding carbon nanotubes in the fibers of a bandage, scientists at the University of Rhode Island have created a continuous, noninvasive way to detect and monitor an infection in a wound. The "smart bandage" can be monitored by a miniaturized wearable device, which wirelessly detects the signal from the carbon nanotubes in the bandage. The signal can then be transmitted to a smartphone-type device that automatically alerts the patient or a health care provider.

Scientists at the National Institute of Standards and Technology (NIST) have miniaturized the optical components required to cool atoms down to a few thousandths of a degree above absolute zero. Light is launched from an optical integrated circuit using a device called an extreme mode converter. The converter enlarges the narrow laser beam, which then strikes an ultrathin film known as a metasurface, which is studded with tiny nanopillars that act to further widen the laser beam. The dramatic widening allows the beam to interact with and cool a large collection of atoms. 

Researchers from Caltech, California State University, Northridge, and the National Institute for Materials Science in Tsukuba, Japan, have found that magic-angle twisted bilayer graphene has unexpected topological quantum phases. The researchers used scanning tunneling microscopy to directly image twisted bilayer graphene with atomic resolution and found that the strong interactions between electrons in twisted bilayer graphene enable the emergence of these topological phases without the need for a strong magnetic field. 

Typically, bioelectronics are created through a "top-down" approach, with the electronics already put together and made smaller to fit with a biological system. But researchers from the University of Chicago and Northwestern University have taken a "bottom-up" approach, in which small building blocks, called micelles, come together to form carbon-based bioelectronics. The small micelles come together to form very thin sheets that are nanoporous – covered with extremely tiny holes – and allow for more flexibility. 

When sheets of two-dimensional nanomaterials, such as graphene, are stacked on top of each other, tiny gaps form between the sheets that have a wide variety of potential uses. Now, a team of researchers from Brown University has found a way to orient those gaps, called nanochannels, in a way that makes them more useful for filtering water and other liquids of nanoscale contaminants.