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

Scientists at Princeton University have, for the first time, successfully visualized the elusive Wigner crystal – a strange form of matter made only of electrons that assemble into a crystal-like formation of their own (without the need to coalesce around atoms). The scientists cooled the sample down to extremely low temperatures—just a fraction of a degree above absolute zero—and applied a magnetic field perpendicular to the sample, which created a two-dimensional electron gas system between two thin layers of graphene – a two-dimensional material made of carbon atoms. “Our work provides the first direct images of this crystal,” said Yen-Chen Tsui, one of the scientists involved in this study. “We proved the crystal is really there and we can see it.”

Researchers from the University of California, Berkeley, the U.S. Department of Energy’s Berkeley Lab, and the National Institute for Materials Science in Tsukuba, Japan, have taken the first atomic-resolution images and demonstrated electrical control of a chiral interface state – an exotic quantum phenomenon that could help researchers advance quantum computing and energy-efficient electronics. To prepare chiral interface states, the researchers worked at the Molecular Foundry, a user facility at Berkeley Lab, to fabricate a device called twisted monolayer-bilayer graphene, which is a stack of two atomically thin layers of graphene rotated precisely relative to one another.

Silver nanoparticles are highly sought-after products in the nanotechnology industry because of their antibacterial, antifungal, antiviral, electrical, and optical properties. Now, researchers from the U.S. Department of Agriculture (USDA)'s Agricultural Research Service and Oklahoma State University have revealed the ability of cotton gin waste – a byproduct from the process that separates fibers from the seeds of cotton – to synthesize and generate silver nanoparticles in the presence of silver ions. The researchers used a simple heat treatment of cotton gin waste materials in water containing silver ions that produced silver nanoparticles without the need for additional chemical agents.

Researchers from the University of California Santa Cruz have created a lab-on-a-chip diagnostic system that combines optofluidics and nanopore technology. To run the test, a sample of biofluid is mixed in a container with magnetic microbeads. The microbeads are designed with a matching RNA sequence of the disease for which the test is designed to detect. The microbeads are put into a silicon microfluidics chip, where they are caught in a light beam that pushes them against a wall that contains a nanopore. The researchers apply heat to the chip, which makes the RNA sequences come off the microbeads and get sucked into the nanopore, which detects that the virus RNA is present.

Researchers at the Massachusetts Institute of Technology have found that neutrons can be made to cling to nanoparticles called quantum dots, which are made up of tens of thousands of atomic nuclei, held there by the strong force. Until this new work, nobody thought that neutrons might actually stick to the materials they were probing. “The fact that [the neutrons] can be trapped by the materials, nobody seems to know about that,” said Ju Li, one of the scientists involved in this study. “We were surprised that this exists.”

Engineers from the University of Massachusetts Amherst, Florida Institute of Technology, and the U.S. Naval Research Laboratory have created ultraviolet (UV) rays-emitting glass that can reduce 98% of biofilm from growing on surfaces in underwater environments. Says lead study author Leila Alidokht, "As UV enters the glass, we scatter the UV from inside of the glass to the outside," using a coating made of light-scattering silica nanoparticles. "Contrary to an external UV irradiation technique, UV-emitting glass inhibits biofilm formation directly at the surface of interest – the surface itself serves as a UVC source," Alidokht adds.

A University at Buffalo–led research team has published research on overcoming traditional limitations for using nickel nanoparticle-based catalysts to turn climate-warming methane emissions into useful commercial products. Methane is a byproduct in many industries, including natural gas and crude oil production, livestock farming, landfilling, and coal mining. The researchers developed an aerosolized process that created catalysts in one step, allowing them to identify the highest-performing catalysts. The resulting spherical nanoshell catalyst dramatically outperformed conventional catalysts in converting methane and carbon dioxide into useful products. The technology also has potential applications in semiconductors, biotechnology, electrochemistry and other fields in need of new and improved materials.

Purdue University researchers have reported on their efforts to develop and validate poly (lactic-co-glycolic acid), or PLGA, nanoparticles modified with adenosine triphosphate, or ATP, to enhance immunotherapy effects against malignant tumors. They found that tumors grew slower in mice treated with paclitaxel ((a chemotherapy drug used to treat several types of cancers) ) enclosed within ATP-modified nanoparticles than in mice treated with paclitaxel in non-modified nanoparticles.

An international team of scientists has used the Advanced Light Source at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) to discover two new nanoscale calcium carbonate mineral phases on freshly deposited coral skeleton and nacre surfaces. These materials, which have been described and characterized only recently, have never been found in nature. These findings suggest that the biomineralization pathways used by marine animals are more complex and diverse than previously realized. This research provides insights on how marine life will respond to environmental changes such as more acidic oceans caused by climate change.

A Stanford University research team has used a 3D nanoprinting technique to produce Archimedean truncated tetrahedrons (ATTs). ATTs, micrometer-scale tetrahedrons with trimmed tips, have been theorized as having geometries that could produce phase-shifting materials, but are challenging to create in the real world. 3D printing could allow for precise control of particle shape and geometry to produce materials with novel physical properties.