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

Researchers at the University of Minnesota and the University of Arizona have provided new insights into how next-generation electronics break down or degrade over time. Using a sophisticated electron microscope, the researchers looked at the nanopillars within magnetic tunnel junctions – the building blocks for the non-volatile memory in smart watches and in-memory computing. The researchers ran a current through the device to see how it operates. As they increased the current, they were able to observe how the device degrades and eventually dies in real time. “What was unusual with this discovery is that we observed this burn out at a much lower temperature than what previous research thought was possible,” said Andre Mkhoyan, one of the scientists involved in this research.

Researchers from the University of Pennsylvania have demonstrated a new kind of nanopore platform that consists of two or more nanopores stacked just nanometers apart, allowing for more precise detection and control of DNA as it wiggles through. “With current platforms, when molecules like DNA are placed near the nanopores, it’s sort of like having spaghetti in a pot—tangled and difficult to work with, let alone guiding through one hole,” explains Dimitri Monos, one of the scientists involved in this study. “So, typically, researchers need to use proteins to capture, unwind, and straighten it, which, while effective, has many limitations. But with this new design, we’re essentially guiding molecules through two coupled nanopores in the material, providing a controlled, smoother passage of molecules.”

The National Institute for Occupational Safety and Health’s Nanotechnology Research Center (NTRC) is celebrating its 20-year anniversary! Over the years, researchers at the NTRC have studied the #toxicity of many engineered nanomaterials throughout their life cycles. The research has covered primary manufactured forms (such as carbon nanotubes, nanoscale titanium dioxide, and silver nanoparticles) and modified versions for specific applications (such as silica-coated iron oxide, heat-treated carbon nanotubes, and reduced graphene oxide). Early studies focused on the tiniest components of air pollution, known as ultrafine particles, which laid the foundation for ongoing research efforts to assess two types of nanoparticles found in workplaces: engineered nanomaterials (purposely created for various applications) and process-derived nanoparticles (unintentionally produced during industrial processes). Also, using samples from worker health effects studies, researchers developed toxicology studies to determine biomarkers of exposure and disease. Together, these studies offer valuable data for understanding workplace hazards and risks. 

Researchers at the University of Chicago Medicine Comprehensive Cancer Center have developed a nanomedicine that increases the penetration and accumulation of chemotherapy drugs in tumor tissues and effectively kills cancer cells in mice. The researchers looked at a particular pathway known as stimulator of interferon genes (STING), whose activation increases the leakiness of blood vessels near the tumor. They designed nanoparticles that encapsulates both STING activators and chemotherapy drugs and evaluated the antitumor effects of the therapy in multiple kinds of tumors in mice; they found large tumor growth inhibition and high cure rates.

Researchers from Duke University, the University of California, Los Angeles, the Icahn School of Medicine at Mount Sinai, and Harvard Medical School have developed a platform that uses sound waves as acoustic tweezers to sort viruses from other compounds in a liquid. The platform consists of a rectangular chip with a sample-loading inlet at one end and separate virus and waste outlets at the other end. Two acoustic beams were applied across the chip, perpendicular to the sample flow. Particles larger than 150 nanometers (nm) in diameter were trapped on the chip, particles smaller than 50 nm left through the waste outlet, and viruses of intermediate sizes (50 to 150 nm) were collected via the virus outlet.

A team of scientists from the U.S. Department of Energy's Oak Ridge National Laboratory and the University of Maine has identified and successfully demonstrated a new method to process a plant-based material, called nanocellulose, that reduced energy needs by a whopping 21%. The approach was discovered using molecular simulations that were run on the lab's supercomputers, followed by pilot testing and analysis. The method can significantly lower the production cost of nanocellulosic fiber and supports the development of a circular bioeconomy, in which renewable, biodegradable materials replace petroleum-based resources.

Researchers at the Massachusetts Institute of Technology have developed a new filtration material that might provide a nature-based solution to water contaminated by “forever chemicals,” or per- and poly-fluoroalkyl substances (PFAS). The filtration material, based on natural silk and cellulose, can remove a variety of these persistent chemicals, as well as heavy metals. The researchers devised a way of processing silk proteins into uniform nanoscale crystals, or “nanofibrils.” Then, they integrated cellulose into the silk-based fibrils, which formed a thin membrane that was highly effective at removing PFAS in lab tests.

Researchers at Stanford University have developed a new way to see organs within a body by rendering overlying tissues transparent to visible light. The counterintuitive process – a topical application of a common food dye – was reversible in tests with animal subjects and may ultimately apply to a wide range of medical diagnostics, from locating injuries to monitoring digestive disorders to identifying cancers. To conduct their research, the scientists used a tool called an ellipsometer at the Stanford Nano Shared Facilities – open access facilities that are part of the National Science Foundation-funded National Nanotechnology Coordinated Infrastructure (NNCI). “Open access to such instrumentation is foundational for making groundbreaking discoveries, as those instruments can be deployed in new ways to generate fundamental insights about scientific phenomena,” said NSF Program Officer Richard Nash, who oversees the NSF NNCI. 

A research team from Brown University has developed a new method for transferring the ions that mass spectrometers analyze, dramatically reducing sample loss so that nearly all of it remains intact. "Basically, it's a process where you're really spraying your sample all over the place to produce these ions and only get a tiny portion of them into the mass spectrometer's vacuum for analysis,” said Nicholas Drachman, a physics Ph.D. student who led the work. “Our approach skips all of that." The key is a nanotube the researchers developed that has an opening about 30 nanometers across. For comparison, the conventional needle used in electrospray has an opening of about 20 micrometers across. The new nanotube also has the unique ability to transfer ions that are dissolved in water directly into the vacuum of a mass spectrometer, rather than producing a spray of droplets that must be dried out to access the ions.

A team of researchers from Georgia Tech, Georgia State University, and Emory University has developed a therapy to target and kill dengue virus using the gene editing tool CRISPR-Cas13. The team used lipid nanoparticles that carried a custom-coded messenger RNA (mRNA) molecule. The mRNA encodes for a CRISPR protein that cuts viral RNA. When the encoded mRNA was delivered to infected cells, the cells used the mRNA instructions to build the CRISPR protein, which degraded the viral RNA within the cells. Thanks to this treatment, the team was able to treat dengue virus in mice.