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

Scientists from the Massachusetts Institute of Technology and the National Institute for Materials Science in Tsukuba, Japan, have discovered that electrons can form crystalline structures in materials composed of either four or five layers of graphene. (Graphene is a one-atom-thick layer of carbon atoms arranged in hexagons, which looks like a honeycomb structure.) Last year, the scientists reported that electrons became fractions of themselves upon applying a current to a material composed of rhombohedral pentalayer graphene and hexagonal boron nitride. This time, the scientists have shown that electrons can become fractions of themselves without a magnetic field. They also found that what they saw last time can be understood to emerge in an electron “liquid” phase, analogous to water, and what they have now observed can be interpreted as an electron “solid” phase that looks like the formation of electronic “ice.”

Researchers from the Molecular Foundry, a user facility at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory, Columbia University, and Universidad Autónoma de Madrid in Spain have developed a new optical computing material from photon-avalanching nanoparticles. This approach offers a path toward realizing smaller, faster components for next-generation computers by taking advantage of intrinsic optical bistability – a property that allows a material to use light to switch between two different states, such as glowing brightly or not at all. For decades, researchers have sought ways to make a computer that uses light instead of electricity. But in previous studies, optical bistability had almost exclusively been observed in bulk materials that were too big for a microchip and challenging to mass produce. Now, the researchers suggest that the new photon-avalanching nanoparticles could overcome these challenges in realizing optical bistability at the nanoscale.

Using an approach called DNA origami, scientists at Caltech have developed a technique that could lead to cheaper, reusable biomarker sensors for quickly detecting proteins in bodily fluids, eliminating the need to send samples out to lab centers for testing. DNA origami enables long strands of DNA to fold, through self-assembly, into molecular structures at the nanoscale. In this study, DNA origami was used to create a lilypad-like structure – a flat, circular surface about 100 nanometers in diameter, tethered by a DNA linker to a gold electrode. Both the lilypad and the electrode have short DNA strands available to bind with an analyte, a molecule of interest in solution – whether that be a molecule of DNA, a protein, or an antibody. 

Scientists from the University of Oklahoma and Northwestern University have shown that adding a crystalized molecular layer to quantum dots made of perovskite prevents them from darkening or blinking. Quantum dots, which are nanoparticles that have unique optical and electronic properties, usually fade out after 10–20 minutes of use. The crystal coverings developed in this study extend the continuous light emission of quantum dots to more than 12 hours with virtually no blinking. According to Yitong Dong, the scientist who led this study, these findings pave the way for the future design of quantum emitters – devices that emit single photons on demand, with applications in quantum computing. 

Researchers from the University of Connecticut; Harvard University; the Massachusetts Institute of Technology; RTX BBN Technologies in Arlington, VA; and the National Institute for Materials Science in Tsukuba, Japan, have discovered that electrons in twisted trilayer graphene behave unlike those described by Bardeen-Cooper-Schrieffer theory of paired electrons. However,  twisted trilayer graphene shares properties with high-temperature cuprates, in which electrons also pair up, but differently from traditional superconductors. Many previous studies in graphene are limited in describing superconductivity, because those experiments focus on the properties of single electrons rather than electron pairs, says Pavel Volkov, one of the researchers involved in this study. "What matters is that electrons form pairs, and somehow you want to probe the properties of those pairs to be able to study superconductivity,” he says.

Researchers at the University of Pennsylvania have demonstrated that ferumoxytol, an U.S. Food and Drug Administration-approved iron oxide nanoparticle formulation, greatly reduces infection in patients diagnosed with apical periodontitis. The researchers showed that topical applications of ferumoxytol in combination with hydrogen peroxide potently disrupt biofilms – dense, sticky communities of bacteria that attach to surfaces and cause infections. The researchers treated 44 patients with periapical periodontitis and found that patients who received ferumoxytol/hydrogen peroxide achieved a 99.9% reduction in bacterial counts without experiencing any adverse effects.

Researchers from Cedars-Sinai Cancer; Caltech; California State University, Northridge; and Technion-Israel Institute in Haifa, Israel, have designed nanobioparticles that can cross the protective blood–brain barrier and deliver therapy directly into cancerous tumor cells. The findings could help clinicians target brain tumors previously unreachable by chemotherapy. The investigators conducted experiments using a unique blood-brain barrier "organ chip." When investigators flowed the nanobioparticles through the blood vessel portion of the chip, they saw that it crossed over and accumulated in the brain matter. 

Researchers from the University of Pennsylvania, Rutgers University, and East China University of Science and Technology in Shanghai have shown that a combination of messenger RNA (mRNA) and a new lipid nanoparticle could help heal damaged lungs. The researchers matched up mRNA with just one unique lipid nanoparticle – ionizable amphiphilic Janus dendrimers – which are organ-specific. When it reaches the lung, the mRNA instructs the immune system to create transforming growth factor beta, a signaling molecule that is used to repair tissue. “This research marks the birth of a new mRNA delivery platform,” said 2023 Nobel laureate Drew Weissman, a co-author of the study. “While using other lipid nanoparticles works great to prevent infectious diseases, … this new platform does not have to be stored at such extremely cold temperatures and is even easier to produce.” 

Researchers from Baylor College of Medicine and Pennsylvania State University have discovered that Zika virus builds a series of tiny tubes, called tunneling nanotubes, that facilitate the transfer of viral particles to neighboring uninfected cells. The tiny conduits also provide a means to transport RNA, proteins and mitochondria, a cell’s main source of energy, from infected to neighboring cells. “Altogether, we show that Zika virus uses a tunneling strategy to covertly spread the infection in the placenta while hijacking mitochondria to augment its propagation and survival,” said Indira Mysorekar, one of the scientists involved in this study. “We propose that this strategy also protects the virus from the immune response.” 

Using the nanostructures and microstructures found on Morpho butterfly wings, scientists at the University of California San Diego have developed a simple and inexpensive way to analyze cancerous tissues. Fibrosis, the accumulation of fibrous tissue, is a key feature of many diseases, including cancer, and evaluating the extent of fibrosis in a biopsy sample can help determine whether a patient’s cancer is in an early or advanced stage. The researchers discovered that by placing a biopsy sample on top of a Morpho butterfly wing and viewing it under a standard microscope, they can assess whether a tumor’s structure indicates early- or late-stage cancer – without the need for stains or costly imaging machines.