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

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. 

Researchers from Harvard University, Harvard Medical School, the Massachusetts Institute of Technology, the University of Iowa, and the University of Edinburgh in the United Kingdom have developed a platform to streamline the discovery and cost-effective manufacturing of nanosensors that can detect proteins, peptides, and small molecules by increasing their fluorescence up to 100-fold in less than a second. A key component of the platform is fluorogenic amino acids that can be encoded into target-binding small protein sequences. “Essentially, we retrofitted the protein synthesis process for the construction of binding-activated fluorescent nanosensors,” said Jonathan Rittichier, one of the researchers involved in this study.

In the 1970s, scientists began exploring ways to extend electronic frequency mixing into the terahertz range using diodes. While these early efforts showed promise, progress stalled for decades. Recently, however, advances in nanotechnology have reignited this area of research. Now, researchers at the Massachusetts Institute of Technology have developed an electronic frequency mixer for signal detection that operates beyond 0.350 petahertz using tiny nanoantennae. These nanoantennae can mix different frequencies of light, enabling analysis of signals oscillating orders of magnitude faster than the fastest signal accessible to conventional electronics.

Researchers from the University of California, Riverside, and the University of Minnesota have developed magnetic nanoparticles that ensure safe rewarming of frozen tissues for transplant and address the issue of uneven heating due to inhomogeneous nanoparticle distribution. The researchers immersed animal tissues in a solution containing magnetic nanoparticles and a cryoprotective substance, and the solution was subsequently frozen with liquid nitrogen. The researchers then applied an alternating magnetic field, which initiated the rapid rewarming of the tissues, followed by a horizontal static magnetic field, which realigned the nanoparticles, effectively tapping the brakes on heat production.

Researchers at the University of Pennsylvania have found that small extracellular vesicles are secreted by tumor cells and act as a "forcefield," blocking nanoparticle-based therapies aimed at targeting cancers. "A lot like the Death Star with its surrounding fleet of fighter ships and protective shields, solid tumors can use features like immune cells and vasculature to exert force, acting as a physical barrier to rebel forces (nanoparticles) coming in to deliver the payload that destroys it," said Michael Mitchell, one of the researchers involved in this study.