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

Putting 50 billion transistors into a microchip the size of a fingernail is a feat that requires manufacturing methods of nanometer-level precision. The process relies heavily on solvents that carry and deposit materials in each layer – solvents that can be difficult to handle and toxic to the environment. Now, researchers from Tufts University and Istituto Italiano di Tecnologia in Milan, Italy, have developed a nanomanufacturing approach that uses water as the primary solvent, making it more environmentally compatible and opening the door to the development of devices that combine inorganic and biological materials.

Researchers from the University of California San Diego have developed an innovative approach to multispectral photodetection by alternating layers of graphene and colloidal quantum dots. By carefully engineering the material stack, the researchers created photodetectors sensitive to different wavelength bands without additional optical components. The key innovation lies in using graphene monolayers as independent charge collectors at different depths within a quantum dot absorber layer.

Researchers from Penn State and the National Institute for Materials Science in Japan have created a switch that turns on and off the presence of “kink states” – electrical conduction pathways at the edge of semiconducting materials. By controlling the formation of the kink states, researchers can regulate the flow of electrons in a quantum system. Kink states exist in a quantum device built with a bilayer graphene, which comprises two layers of atomically thin carbon stacked together, in such a way that the atoms in one layer are misaligned to the atoms in the other. "The amazing thing about our devices is that we can make electrons moving in opposite directions not collide with one another … even though they share the same pathways," said Ke Huang, one of the scientists involved in this study.

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.