(Funded by the U.S. Department of Energy and the U.S. Food and Drug Administration)
Scientists from the U.S. Food and Drug Administration, Northwestern University, and the Illinois Institute of Technology have found evidence that silver nanoparticles embedded in packaging used as an antimicrobial agent were able to seep into the dry food the packaging is meant to protect. The scientists created samples of silver nanoparticles and embedded them in polyethylene film wraps, which could hold various types of food items. They tested wheat flour, slices of cheese, ground rice, and spinach leaves. They found that the nanoparticles had made their way to all the foods, though to varying degrees. They found, for example, that there was far more contamination of the cheese than there was of the spinach leaves.

(Funded by the U.S. National Science Foundation)
Measuring temperature and humidity in a variety of crop-growing circumstances has prompted the development of numerous sensors, but ensuring these devices are effective while remaining environmentally friendly and cost-effective is a challenge. Now, researchers at Auburn University in Alabama have developed paper-based temperature and humidity sensors that are accurate and reliable, as well as eco-friendly. The researchers created the sensors by printing silver lines on four types of commercially available paper through a process called dry additive nanomanufacturing. The sensors successfully detected changes in relative humidity levels from 20% to 90% and temperature variations from 25°C to 50°C.

(Funded by the U.S. Department of Energy and the U.S. National Science Foundation)
University of Missouri scientists are unlocking the secrets of halide perovskites – a material that might bring us closer to energy-efficient optoelectronics. The scientists are studying the material at the nanoscale. At this level, the material is astonishingly efficient at converting sunlight into energy. To optimize the material for electronic applications, the scientists used a method called ice lithography, known for its ability to fabricate materials at the nanometer scale. This ultra-cool method allowed the team to create distinct properties for the material using an electron beam.

(Funded by the U.S. National Science Foundation, the U.S. Department of Defense, and the National Institutes of Health)
Researchers from Northwestern University, Duke University, and Cornell University have developed the first two-dimensional mechanically interlocked material. Looking like the interlocking links in chainmail, the nanoscale material exhibits exceptional flexibility and strength. With further work, this material holds promise for use in high-performance, light-weight body armor and other uses that demand lightweight, flexible, and tough materials. “We made a completely new polymer structure,” said William Dichtel, the study’s corresponding author. “It’s similar to chainmail in that it cannot easily rip because each of the mechanical bonds has a bit of freedom to slide around. If you pull it, it can dissipate the applied force in multiple directions. And if you want to rip it apart, you would have to break it in many, many different places.”

(Funded by the U.S. National Science Foundation)
Researchers from Case Western Reserve University, the University of Illinois Urbana-Champaign, Adamas Nanotechnologies (Raleigh, NC), the University of Luxembourg in Luxemburg, Umeå University in Sweden, and Aix Marseille University in France have found that boron-doped diamonds exhibit plasmons – waves of electrons that move when light hits them – allowing electric fields to be controlled and enhanced on a nanometer scale. Previously, boron-doped diamonds were known to conduct electricity and become superconductors, but not to have plasmonic properties. Plasmonic materials, which affect light at the nanoscale, have captivated humans for centuries. For example, the vibrant colors in medieval stained-glass windows result from metal nanoparticles embedded in the glass, and when light passes through, these nanoparticles generate plasmons that produce specific colors.