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

Researchers from the National Institute of Standards and Technology; Hyperfine Inc. in Guilford, CT; and the University of Florence in Italy have discovered that nanoparticles can boost image quality in low-field magnetic resonance imaging (MRI) scans. The researchers found that iron oxide nanoparticles outperformed traditional contrast agents, which are used in conventional MRI machines and are made of the element gadolinium. At low magnetic field strength, the nanoparticles provided good contrast using a concentration of only about one-ninth that of the gadolinium particles.

A new technology being pioneered at Caltech is allowing researchers from Caltech and Northrop Grumman Corporation to "evolve" optical devices and then print them out using a specialized type of 3D printer. These devices are made of so-called optical metamaterials that derive their properties from structures so small they are measured in nanometers, and they may allow cameras and sensors to detect and manipulate properties of light in ways not previously possible at small scales.

Researchers from the Nanotechnology and Advanced Spectroscopy Team at the U.S. Department of Energy’s Los Alamos National Laboratory and the Center for Nanoscale Materials at the U.S. Department of Energy’s Argonne National Laboratory have devised a new approach to developing semiconductor materials at tiny scales. The researchers incorporated magnetic dopants into specially engineered colloidal quantum dots – nanoscale-size semiconductor crystals – and were able to achieve effects that may power solar cell technology, photodetectors and applications that depend on light to drive chemical reactions.

Researchers at Drexel University have produced a titanium oxide nanofilament material that can harness sunlight to unlock the potential of titanium dioxide as a fuel source. The discovery offers an alternative to current methods, which generate greenhouse gas and require a great deal of energy. "Our titanium oxide one-dimensional nanofilaments #photocatalyst showed activity that is substantially higher – by an order of magnitude – than its commercial titanium oxide counterpart," said Hussein O. Badr, one of the scientists involved in this study. 

University of Texas at Dallas scientists have discovered a previously unknown "housekeeping" process in kidney cells that ejects unwanted content, resulting in cells that rejuvenate themselves and remain functioning and healthy. The scientists focused on gold nanoparticles, which are used as imaging agents, and investigated how they are filtered by the kidneys and cleared from the body through urine. "In the field of nanomedicine, we want to minimize accumulation of nanoparticles in the body as much as possible," said Jie Zheng, one of the scientists involved in this study. “We don't want them to get stuck in the kidneys, so it's very important to understand how nanoparticles are eliminated from the proximal tubules.”

Researchers at Washington University in St. Louis have pioneered a new technique that will enable higher-resolution imaging of very small objects, such as neurons. The technique uses ultrabright fluorescent markers, called plasmonic-fluors, that are constructed from a nanoparticle of gold wrapped in a silver shell, which is then covered with a layer of light-emitting markers, called fluorophores. Interactions between the gold-silver nanoparticle and the fluorophores causes the fluorophores to emit more photons than they normally would. As a result, the plasmonic-fluor is nearly four orders of magnitude brighter than the fluorescent markers would be on their own. 

Rice University scientists have used light-activated molecular machines to trigger intercellular calcium wave signals, revealing a powerful new strategy for controlling cellular activity. "Most of the drugs developed up to this point use chemical binding forces to drive a specific signaling cascade in the body," said Jacob Beckham, the lead author on the study. "This is the first demonstration that, instead of chemical force, you can use mechanical force – induced, in this case, by single-molecule nanomachines – to do the same thing, which opens up a whole new chapter in drug design."

Researchers at Columbia University have shown that tiny organic transistors enabled an implanted device to acquire and transmit neurophysiologic brain signals while simultaneously providing power to the implanted device. The researchers used advanced nanofabrication techniques to miniaturize and densify these transistors at sub-micrometer scales. The researchers also demonstrated that these implants can be made soft and conformable and can record and transmit high-resolution neural activity from both outside, on the surface of the brain, as well as inside, deep within the brain. 

Researchers at the Massachusetts Institute of Technology have created a technique that allows individual halide perovskite nanocrystals to be grown on-site where needed with precise control over location to within less than 50 nanometers. The researchers used this technique to create arrays of nanoscale light-emitting diodes (LEDs) – tiny crystals that emit light when electrically activated. Such arrays could have applications in optical communication and computing, lensless microscopes, new types of quantum light sources, and high-density, high-resolution displays for augmented and virtual reality.

Researchers from Oregon State University; Columbia University; the U.S. Department of Energy’s Pacific Northwest National Laboratory; and Chemspeed Technologies AG in Switzerland have demonstrated the potential of an inexpensive nanomaterial to scrub carbon dioxide from industrial emissions. The nanomaterial, known as a metal-organic framework, can intercept carbon dioxide molecules through adsorption as flue gases make their way through smokestacks. Unlike other metal-organic frameworks, this one works well in damp conditions and prefers carbon dioxide to nitrogen, which is important because nitrogen oxides are an ingredient in flue gases.