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

Any application of ultrashort laser pulses in the visible spectrum needs to overcome a fundamental difficulty – red light travels faster than blue light through transparent materials like glass. So, when an ultrashort laser pulse passes through a glass lens, the tightly packed wavelengths of light separate, destroying the usefulness of the beam. This chromatic dispersion problem has plagued optical researchers for decades. Now, researchers at Harvard University have developed a silicon coating made of nanopillars that, when applied to the surface of a glass lens, can counteract the effects of chromatic dispersion.

Researchers at Northwestern University have developed a new injectable therapy that reverses paralysis and repairs tissue after severe spinal cord injuries. The researchers administered a single injection to tissues surrounding the spinal cords of paralyzed mice. Just four weeks later, the animals regained the ability to walk. A key part of this therapy is that bioactive signals are sent to trigger cells to repair and regenerate. Injected as a liquid, the therapy immediately gels into a complex network of nanofibers that mimic the extracellular matrix of the spinal cord.

Fluorescent "dots"—nanoparticles that can emit light—have a multitude of promising biomedical applications, from helping clinicians to better identify tumor margins to delivering a drug deep in the body. However, making such dots is usually a long and tedious process that uses harsh chemicals. Now, researchers from the University of Nebraska Medical Center have developed a fluorescent dot that not only is easier to make but also uses environmentally friendly materials.

U.S. and Chinese researchers have developed a modified textile that can keep skin cooler than materials made of cotton. The researchers dipped a standard piece of silk fabric into a liquid solution containing highly refractive inorganic oxide nanoparticles. These nanoparticles adhered to the silk fabric, allowing it to become evenly saturated throughout the material. They found that under peak sunlight conditions, the temperature under the material was approximately 3.5 degrees Celsius cooler than the ambient air temperature.

Researchers from the University of Illinois Urbana-Champaign and GlaxoSmithKline are using nanodiamonds to calibrate and assess the performance of high-powered microscopes. The stability and longevity of these particles ­­– which are a few nanometers to a few hundred nanometers in diameter ­­– allows their continuous reuse as a calibration tool, eliminating the labor-intensive preparation researchers typically undergo.

Researchers at the University of Chicago have found a new way to create and stabilize so-called “blue phase” liquid crystals, which are nanocrystals that have the properties of both liquids and crystals and can, in some cases, reflect visible light better than ordinary liquid crystals. Potential applications include display technologies that could be turned on and off with very small changes in size, temperature, or exposure to light, and sensors that can detect radiation within a certain wavelength. 

A team led by Georgia Tech researchers has discovered unexpectedly familiar behavior in an antiferroelectric material known as zirconium dioxide, or zirconia. They showed that as the microstructure of the material is reduced to a few nanometers in size, it behaves similarly to much better understood materials known as ferroelectrics. In the past few years, antiferroelectric materials have been increasingly studied for potential applications in modern computer memory devices.

Researchers have discovered familiar behavior in an antiferroelectric material. Prof. Nazanin Bassiri-Gharb, of Georgia Tech, who participated in this research, discusses the applications of SMART materials in a recent NNI podcast episode: https://youtu.be/PIjojolu7M8 

Researchers from the University of Illinois at Urbana-Champaign and Delft University of Technology have managed to scan a single protein. By slowly moving a linearized protein through a tiny nanopore, one amino acid at a time, the researchers were able to read off electric currents that relate to the information content of the protein. The new single-molecule peptide reader marks a breakthrough in protein identification, and opens the way toward single-molecule protein sequencing and cataloguing the proteins inside a single cell.

To build modern electrical circuits, researchers control silicon's current-conducting capabilities via doping. Silicon's 3D lattice, however, is too big for next-generation electronics, so researchers are experimenting with graphene, but the tried-and-true method for doping 3D silicon doesn’t work for 2D graphene. An interdisciplinary team of researchers led by Columbia University developed a technique to dope graphene via a charge-transfer layer made of low-impurity tungsten oxyselenide (TOS). This combination of high doping and high mobility gives graphene greater #electrical #conductivity than that of highly conductive #metals, such as copper and gold.