An official website of the United States government.
This online post from the U.S. Food and Drug Administration states that “[m]icroplastics and nanoplastics may be present in food, primarily from environmental contamination where foods are grown or raised,” but “[c]urrent scientific evidence does not demonstrate that levels of microplastics or nanoplastics detected in foods pose a risk to human health.”
Caltech engineers have built a metasurface patterned with tunable nanoscale antennas capable of reflecting an incoming beam of optical light to create many channels of different optical frequencies. The work points to a promising route for the development of not only a new type of wireless communication channel but also potentially new range-finding technologies and even a novel way to relay larger amounts of data to and from space. "With these metasurfaces, we've been able to show that one beam of light comes in, and multiple beams of light go out, each with different optical frequencies and going in different directions," says Harry Atwater, one of the engineers involved in this study. "It's acting like an entire array of communication channels. And we've found a way to do this for free-space signals rather than signals carried on an optical fiber."
Researchers from North Carolina State University, the Leibniz Institute of Polymer Research Dresden in Germany, Technische Universität Dresden in Germany, and Otto von Guericke University Magdeburg in Germany have embedded gold nanorods in hydrogels that can be processed through 3D printing to create structures that contract when exposed to light and expand when the light is removed. When the hydrogel structures are exposed to light, the embedded gold nanorods convert that light into heat. This causes the polymers in the hydrogel to contract, pushing water out of the hydrogel and shrinking the structure. When the light is removed, the polymers cool down and begin absorbing water again, which expands the hydrogel structure to its original dimensions. Because this expansion and contraction can be performed repeatedly, the 3D-printed structures can serve as remotely controlled actuators.
Researchers from the University of Maryland and the National Institute of Standards and Technology have engineered a seafood-waste material that removes chemical pesticides and herbicides from produce and extends shelf life. The material, made of a derivative of crab and shrimp shells, is designed to form a thin nanocrystal layer on the treated produce, removing chemical residues. The researchers used a smartphone app to check the chemical residue level. They found that this coating was effective in absorbing the chemical residues, enhanced the fruit's shelf life, and was easily rinsed off.
Researchers from Johns Hopkins University, the University of Texas Southwestern Medical Center, St. Jude Children's Research Hospital, and Harvard University have developed nanoparticles that can send gene treatment directly to various types of cells in bone marrow to correct mutations that cause sickle cell disease. The researchers used CRISPR/Cas and base gene-editing techniques in a mouse model of sickle cell disease to activate a form of hemoglobin and correct the sickle cell mutation.
Researchers from Vanderbilt University, Yale University, Northwestern University, and AstraZeneca have developed a set of nanoparticles that stimulate the immune system in mice to fight cancer and may eventually do the same in humans. The nanoparticles delivered a nucleic acid molecule that triggers an immune response that is normally used by the body to recognize foreign viruses to help the immune system mount a defense, according to the researchers.
Engineers at Johns Hopkins University have created a new optical tool that could improve cancer imaging. Their approach uses tiny nanoprobes that light up when they attach to aggressive cancer cells, helping clinicians distinguish between localized cancers and those that are metastatic and have the potential to spread throughout the body. The team found that unlike CT or MRI scans, the nanoprobes effectively and consistently bound to metastatic prostate cancer cells and differentiated between them and non-metastatic cells.
For the first time, researchers from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), Dartmouth College, Penn State, the University of California, Merced, and Université Catholique de Louvain in Belgium have demonstrated an approach that combines high-throughput computation and atomic-scale fabrication to engineer high-performance quantum defects. The researchers developed state-of-the-art, high-throughput computational methods to screen and accurately predict the properties of more than 750 defects in a two-dimensional material called tungsten disulfide. Then, working at the Molecular Foundry, a user facility at Berkeley Lab, the researchers developed and applied a technique that enables the creation of vacancies in tungsten disulfide and the insertion of cobalt atoms into these vacancies.
Researchers from the U.S. Department of Energy’s National Renewable Energy Laboratory have developed a trilayer of semiconductors to enable the dissociation of electron-hole pairs, also called excitons – a fundamental process for the performance of photovoltaic systems. The trilayer, which consists of single-walled carbon nanotubes sandwiched between two semiconductors, enables a photo-induced charge transfer cascade, in which electrons move in one direction, while holes move in the other direction. The trilayer architecture appears to facilitate ultrafast hole transfer and exciton dissociation, resulting in a long-lived charge separation.
Researchers from the University of Rochester have outlined a process for mapping heat transfer using luminescent nanoparticles. By applying highly doped upconverting nanoparticles to the surface of a device, the researchers were able to achieve super-high-resolution thermometry at the nanoscale level from up to 10 millimeters away. According to Andrea Pickel , one of the scientists involved in the study, this method could be used by manufacturers to improve a wide array of electrical components.
