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

(Funded by the National Science Foundation, the U.S. Department of Energy, and the U.S. Department of Defense)

Researchers at Cornell University have shown that a single material system can toggle between two of the wildest states in condensed matter physics: the quantum anomalous Hall insulator and the two-dimensional topological insulator. The researchers stacked an ultrathin monolayer of molybdenum ditelluride on top of an ultrathin monolayer of tungsten diselenide, twisting them at a 180-degree angle. After applying a voltage, they observed the quantum anomalous Hall effect. The researchers also found that by simply tweaking the voltage, they could turn their semiconductor stack into a two-dimensional topological insulator.

(Funded by the U.S. Department of Energy, the National Science Foundation, and the U.S. Department of Defense)

Researchers from Northwestern University and the University of Michigan have shown, for the first time, how low-symmetry colloidal crystals can be made – including one phase for which there is no known natural equivalent. In this research, metal nanoparticles whose surfaces were coated with designer DNA were used to create the crystals. The DNA acted as an encodable bonding material, transforming them into what are called programmable atom equivalents.

(Funded by the National Science Foundation)

Scientists at the University of Oregon have made nanocrystals that are the smallest and most stable kind of metal-organic framework (MOF). Such nanocrystals could have a wide range of potential applications, from surface coatings that can store electric charge to filters that can remove contaminants from air or water. MOFs form via a series of chemical reactions that join metal ions with linker molecules. The scientists added a third ingredient: molecules that mimic the linkers but can only bind to something on one end. Like edge pieces on a jigsaw puzzle, they act like dead-ends for the growing MOF, ensuring it stays small.

(Funded by the U.S. Department of Defense)

Researchers at the University of Michigan and the University of Bath in the United Kingdom have shown that twisted nanoscale semiconductors can manipulate light in a new way. The photonic effect could help enable rapid development and screening of new antibiotics and other drugs through automation. It offers a new analysis tool for high-throughput screening, a method to analyze vast libraries of chemical compounds.

(Funded by the National Institutes of Health)

When injected into the bloodstream, unmodified nanoparticles are swarmed by elements of the immune system called complement proteins, triggering an inflammatory response and preventing the nanoparticles from reaching their therapeutic targets in the body. Now, researchers at the University of Pennsylvania have invented what may be the best method yet to address this issue: coating the nanoparticles with natural suppressors of complement proteins.

(Funded by the U.S. Department of Defense, the U.S. Department of Energy and the National Science Foundation)

Scientists from Brown University, Columbia University, Harvard University, and the National Institute for Materials Science in Japan have created a tunable, graphene-based platform that uses opposite charges—electrons and holes—to form quantum particle pairs under strong magnetic fields. The strength of the pairing can be varied along a continuum, which allows the scientists to test theoretical predictions about the origins of quantum condensates and how they might increase the temperature limits of superconductivity.

(Funded by the National Institutes of Health)

Standard chemotherapies may efficiently kill cancer cells, but they also pose significant risks to healthy cells, resulting in secondary illness and a diminished quality of life for patients. To prevent these risks, researchers led by Penn State have developed a new class of nanomaterials engineered to capture chemotherapy drugs before they interact with healthy tissue. The method is based on hairy cellulose nanocrystals – nanoparticles developed from the main component of plant cell walls and engineered to have large numbers of polymer chain "hairs," extending from each end.

(Funded in part by the U.S. Department of Energy and the National Science Foundation)

When sheets of graphene are stacked, electrons begin to interact not only with other electrons within a graphene sheet, but also with those in the adjacent sheet. Changing the angle of the sheets with respect to each other changes those interactions, giving rise to interesting quantum phenomena like superconductivity. Now, a research team from Brown University has shown that when two sheets of graphene are stacked together at a particular angle with respect to each other, the bilayer graphene becomes a powerful ferromagnet.

(Funded in part by the U.S. Department of Defense, the National Science Foundation, and the U.S. Department of Energy)

Although twisted sheets of double bilayer graphene have been studied extensively in the past few years, there are still pieces missing in the puzzle that is its phase diagram – the different undisturbed, ground states of the system. Now, an international team of researchers has found a new puzzle piece: an electronic nematic phase. A nematic phase occurs when particles in a material break an otherwise symmetrical structure and come to loosely orient with one another along the same axis. This phenomenon is the basis of the liquid-crystal display commonly used in televisions and computer monitors. 

(Funded by the National Science Foundation and the National Institutes of Health)

Researchers at Johns Hopkins Medicine have developed a color-coded test that quickly signals whether newly developed nanoparticles deliver their cargo into target cells. Historically, nanoparticles have a very low delivery rate to the cytosol, the inside compartment of cells, releasing only about 1%–2% of their contents. The new testing tool, engineered specifically to test nanoparticles, could advance the search for next-generation biological medicines.