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

Researchers from the U.S. Department of Energy’s Argonne National Laboratory and the University of Cambridge have unveiled the existence of an intriguing link between ferroelectric domain walls and electron interactions in a type of van der Waals 2D material. A domain wall is a boundary or interface separating regions inside a material that exhibit different orientations of ferroelectric polarization. The link discovered by the researchers gives rise to a new type of superconductivity that is unique to these 2D materials. "We showed that places like domain walls, typically associated with irregularities and potentially harmful for things like superconductivity, can indeed be helpful for superconductivity," said Gaurav Chaudhary and Ivar Martin, the two authors of this study.

Most cancers occur when there is an imbalance of cellular growth and inhibition, causing cells to grow rapidly and form tumors in the body. In the case of prostate cancer, no therapies exist to simultaneously correct tumor growth and restore tumor suppression. To restore this balance, researchers from Brigham and Women's Hospital, which is part of Harvard Medical School, have used lipid nanoparticles to deliver messenger RNA (mRNA) and small interfering RNA (siRNA) to human prostate cancer cells. This approach was successful in preclinical models, holding promise for suppressing tumor growth in patients. 

Researchers from Stanford University; the IBM T.J. Watson Research Center in Yorktown Heights, NY; the Korea Electronics Technology Institute in Seongnam-si, South Korea; and Ajou University in Suwon, South Korea, have shown that niobium phosphide can conduct electricity better than copper in films that are only a few atoms thick. Many researchers have been working to find better conductors for nanoscale electronics, but so far the best candidates have had extremely precise crystalline structures, which need to be formed at very high temperatures. The niobium phosphide films made in this study are the first examples of non-crystalline materials that become better conductors as they get thinner, and they can be created at lower temperatures. 

Researchers from Carnegie Mellon University have found a way to control the size and structure of active colloids while yielding more than 100 times the amount created by earlier fabrication methods. The team's active colloids are linked together using DNA nanostructures – an innovation that makes them flexible, agile, and responsive to signals in their environment. Typically, DNA nanotechnology can only be studied using expensive equipment. In this case, because the DNA is attached to the colloid particles, researchers can observe any nanoscale phenomenon – such as the DNA structures changing shape – in real time by observing changes in the colloid's movement under a microscope.

Researchers from the U.S. Department of Energy's SLAC National Accelerator Laboratory, Stanford University, and the University of California, Davis, have developed a new software tool that can provide more quantitative details about the structure of the active sites in single atom catalysts in much less time, compared to current methods. Normally, a catalyst uses an inert support to stabilize nanometer-sized clusters of metal atoms, or metal nanoparticles. To maximize the use of each metal atom, researchers also use single atom catalysts, where individual metal atoms are dispersed onto the support. In reality, catalysts usually have both single atoms and nanoparticles, and the new software tool determines the fractions of these two forms.

Scientists from Oregon State University; the Molecular Foundry at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory; Columbia University; and the Autonomous University of Madrid, Spain, have discovered luminescent nanocrystals that can be quickly toggled from light to dark and back again. "Normally, luminescent materials give off light when they are excited by a laser and remain dark when they are not," said Artiom Skripka, one of the scientists involved in this study. "In contrast, we were surprised to find that our nanocrystals live parallel lives. Under certain conditions, they show a peculiar behavior: They can be either bright or dark under exactly the same laser excitation wavelength and power." 

Researchers from Columbia University; the Molecular Foundry at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory; and the University of Utah have invented new nanoscale sensors of force. They are luminescent nanocrystals that can change intensity and/or color when you push or pull on them. These "all-optical" nanosensors are probed with light only and therefore allow for fully remote read-outs—no wires or connections are needed. The nanosensors have an operational range that spans more than four orders of magnitude in force – a much larger range than any previous optical nanosensor.

Bright, twisted light can be produced with technology similar to an Edison light bulb, researchers at the University of Michigan have shown. Usually photons from a blackbody source (which is in thermodynamic equilibrium with its environment) are randomly polarized – their waves may oscillate along any axis. The new study revealed that if the emitter was twisted at the micro or nanoscale, with the length of each twist similar to the wavelength of the emitted light, the blackbody radiation would be twisted, too. This discovery adds nuance to fundamental physics while offering a new avenue for robotic vision systems and other applications for light that traces out a helix in space.

Researchers from Georgia Tech, Emory University, and the University of California, Davis, have created a technique that could lead to new, less-invasive treatments for blood disorders and genetic diseases. "This would be an alternative to invasive hematopoietic stem cell therapies – we could just give you an IV drip," said James Dahlman, one of the researchers involved in this study. "It simplifies the process and reduces the risks to patients.” The procedure uses lipid nanoparticles that carry genetic instructions to hematopoietic stem cells, but unlike current therapies, in this procedure, the nanoparticles don’t have targeting ligands, and they can dodge the liver, which acts as the body's primary blood filter.

Engineers from the Massachusetts Institute of Technology; The University of Texas at Dallas; Sungkyunkwan University in Suwon-si, South Korea; and the Samsung Advanced Institute of Technology in Suwon, South Korea, have created a multilayered chip design that doesn’t require any silicon wafer substrates and works at temperatures low enough to preserve the underlying layer’s circuitry. The multilayered chip consists of alternating layers of two different transition metal dichalcogenides (a type of 2D material): molybdenum disulfide, a promising material candidate for fabricating n-type transistors; and tungsten diselenide, a material that has potential for being made into p-type transistors. Both p- and n-type transistors are the electronic building blocks for carrying out any logic operation. The method will double the density of a chip’s semiconducting elements, particularly metal-oxide semiconductor (CMOS), which is a basic building block of a modern logic circuitry.