News from the NNI Community - Research Advances Funded by Agencies Participating in the NNI

Researchers at the University of Chicago have developed a new way to guide light in one direction on a tiny scale. By coupling light confined in a nanophotonic waveguide with an atomically thin, two-dimensional semiconductor, the researchers exploited the properties of both the light and the material to guide photons in one direction. The resulting small, tunable on-chip photonic interface could lead to smaller photonic integrated circuits that would be integrated into computing systems and self-driving cars.

Scientists at Stanford University have developed the first non-invasive technique for controlling targeted brain circuits in behaving animals from a distance. By artificially outfitting specific neurons in the brains of mice with a heat-sensitive molecule, the scientists found that it was possible to stimulate the modified cells by shining infrared light through the skull and scalp from up to a meter away. The new technique also relies on nanoparticles that can be injected into targeted brain regions to absorb and amplify the infrared light that is going through the brain tissue.

Physicists at MIT and elsewhere have revealed direct evidence of electron correlations – effects from the interaction felt between two negatively charged electrons – in a two-dimensional material called ABC trilayer graphene. In ABC trilayer graphene, three graphene sheets are stacked at the same angle and slightly offset from each other, like layered slices of cheese. An ABC trilayer graphene is similar to the more well-studied magic-angle bilayer graphene, in that both materials involve layers of graphene. Graphene is made from a lattice of carbon atoms arranged in a hexagonal pattern, similar to chicken wire. 

Researchers from the University of California, Irvine; the U.S. Department of Energy’s Brookhaven National Laboratory and Lawrence Livermore National Laboratory; Tokyo University of Agriculture and Technology; Okayama University; and Oxford Instruments Asylum Research have taken a close look at the ultrahard teeth of plant-eating invertebrates, called gumboot chitons, that use their teeth to scrape and grind algal deposits from coastal rocks. The researchers had previously found that these teeth are constructed of highly aligned magnetic nanorods, which provide strength and resistance. This time, the researchers showed, for the first time in natural systems, that at the early stages of tooth development, a pre-assembled organic fibrous material, called chitin, guided the formation of these nanorods via a highly ordered, mesocrystalline iron oxide known as ferrihydrite.

Researchers from MIT (including the Institute for Soldier Nanotechnologies), the U.S. Army Research Institute of Environmental Medicine, the Rhode Island School of Design, Case Western Reserve University, and the University of Wisconsin-Madison have designed an acoustic fabric that incorporates fibers that work like a microphone, converting sound into mechanical vibrations and then into electrical signals. The active layer of the fiber – a composite consisting of a piezoelectric polymer loaded with piezoelectric barium titanate nanoparticles – produces an electrical signal when the fiber is bent or mechanically deformed, providing a means for the fabric to convert sound vibrations into electrical signals.

Researchers from North Carolina State University and the University at Buffalo have developed and demonstrated a "self-driving lab" that uses artificial intelligence and fluidic systems to advance our understanding of metal halide perovskite nanocrystals. These nanocrystals are an emerging class of semiconductor materials that could be used in printed photonic devices and energy technologies. For example, the nanocrystals are efficient optically active materials and are under consideration for use in next-generation light-emitting diodes (LEDs).

Researchers at the University of Central Florida have advanced NASA technologies to develop a power suit for an electric car that is as strong as steel, lighter than aluminum and helps boosts the vehicle’s power capacity. The suit is made of a layered carbon composite material that works as an energy-storing supercapacitor-battery hybrid device due to its unique design at the nanoscale level. To construct the material, the researchers created positively and negatively charged carbon fiber layers that are stacked and attached in an alternating pattern. Nanoscale graphene sheets attached on the carbon fiber layers allow for increased charge-storing ability, while metal oxides deposited on attached electrodes enhance voltage and provide higher energy density.

A team of chemists and biologists at the University of Chicago has developed a nanodevice that can locate immune cells present in solid cancerous tumors and enable them to activate other immune cells so they can attack the tumors. The immune cells targeted by such nanodevices are called tumor-associated macrophages. The nanodevices enable these immune cells to display molecular structures, called antigens, on their surface, which tells other immune cells, called T cells, to attack the tumors. In tests with mice, the use of the nanodevices resulted in tumor regression.

A team of scientists from the Carnegie Institution for Science, the University of Chicago, the U.S. Department of Energy’s Argonne National Laboratory, and the Donostia International Physics Center in Spain has developed a technique that predicts and guides the ordered creation of strong, yet flexible, diamond nanothreads, which are one-dimensional nanomaterials composed of carbon chains. This innovation should make it easier for scientists to synthesize diamond nanothreads.

Researchers at MIT and elsewhere have developed a new type of catalyst material, called a metal hydroxide-organic framework (MHOF), which is made of inexpensive and abundant components. The catalyst speeds up the electrochemical reaction that splits apart water molecules to produce oxygen, which is at the heart of multiple approaches aiming to produce alternative fuels for transportation. The researchers found that MHOFs can match or exceed the performance of conventional, more expensive catalysts; they also found that the number of accessible active on MHOFs is increased significantly by synthesizing them as ultrathin nanosheets.