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

When used as wearable medical devices, stretchy, flexible gas sensors can identify health conditions or issues by detecting oxygen or carbon dioxide levels in the breath or sweat, but manufacturing the devices, which are created using nanomaterials, can be a challenge. Now, Penn State University researchers have enhanced their gas sensor manufacturing process through an in situ laser-assisted manufacturing approach. In the process, a laser inscribes nanomaterials directly on top of a porous graphene foam substrate. The base material allows for the sensor to be stretchy and flexible when applied on the skin or an object.

Researchers at Drexel University have developed a thin film device, fabricated by spray coating, that can block electromagnetic radiation with the flip of a switch. The breakthrough, enabled by versatile two-dimensional materials called MXenes, could adjust the performance of electronic devices, strengthen wireless connections, and secure mobile communications against intrusion.

Researchers from the Massachusetts Institute of Technology; the University of Texas at Dallas; Washington University in St. Louis; the Institute for Basic Science in Pohang, South Korea; Sungkyunkwan University in Suwon-si, South Korea; Yonsei University in Seoul, South Korea; and ISAC Research Inc. in Daejeon, South Korea have developed a method that could enable chip manufacturers to fabricate ever-smaller transistors from 2D materials by growing them on existing wafers of silicon and other materials. With this method, the researchers fabricated a simple functional transistor from a type of 2D materials called transition-metal dichalcogenides, which are known to conduct electricity better than silicon at nanometer scales.

Researchers from the University of Pennsylvania, City University of New York, the University of Amsterdam in the Netherlands, and the AMOLF Institute’s Center for Nanophotonics in the Netherlands have created a nanostructured surface capable of solving equations using light. This discovery opens exciting new opportunities in the field of analog processing based on very thin nanostructured surfaces called metasurfaces. Optical analog processing refers to the use of light to perform analog computations, as opposed to traditional electronic methods which use electricity. 

There are many ways to initiate chemical reactions in liquids, but placing free electrons directly into liquid solutions is especially attractive for green chemistry because electrons in liquids, or solvated electrons, leave behind no side products after they react. Now, chemists at Rice University, Stanford University, and the University of Texas at Austin have uncovered the long-sought mechanism of a well-known but poorly understood process that produces solvated electrons via interactions between light and metal nanoparticles.

A collaborative team of researchers from Oregon Health and Science University and Oregon State University has developed an approach that uses lipid nanoparticles to deliver strands of messenger ribonucleic acid, or mRNA, inside the eye. The team demonstrated how the lipid nanoparticle delivery system targets light-sensitive cells in the eye, called photoreceptors, in both mice and nonhuman primates. The system’s nanoparticles are coated with a peptide that the researchers identified as being attracted to photoreceptors. “Improving the technologies used for gene therapy can provide more treatment options to prevent blindness,” says Renee Ryals, a scientist involved in this study. “Our study’s findings show that lipid nanoparticles could help us do just that.”

Liver fibrosis has remained challenging to treat using RNA therapies due to a lack of delivery systems for targeting activated liver-resident cells called fibroblasts. Both the solid fibroblast structure and the lack of specificity or affinity to target these fibroblasts have impeded current lipid nanoparticles from entering activated liver-resident fibroblasts, and thus they are unable to deliver RNA therapeutics. Now, researchers at the University of Pennsylvania have found a new way to synthesize ligand-tethered lipid nanoparticles, increasing their selectivity and allowing them to target liver fibroblasts. 

Chemists usually make materials by finding the best conditions to target a single product. For example, nanoparticles have been engineered to produce scratch-proof eyeglasses and transparent sunscreen. A research team at Penn State University has flipped this approach on its head by purposely using unoptimized conditions to produce many products at once. This approach allowed them to discover novel nanoparticles, which combine many different materials in various arrangements. They then analyzed these nanoparticles to develop new guidelines that allowed them to make high-yield samples of the most interesting types of new nanoparticles.

Chemists at the University of Oregon have found a way to make carbon-based molecules with a unique structural feature: interlocking rings. These linked-together molecules have interesting properties that can be “tuned” by changing their size and chemical makeup. For example, the researchers made three interlocked rings, as well as a rod-like structure with multiple rings that can slide up and down. The advance grew out of previous work on nanohoops, rings of carbon atoms that are a pared-back variation of long, skinny carbon nanotubes.

Scientists from Northwestern University, the University of Arizona, Washington University in St. Louis, and North Carolina State University have developed a wireless, battery-free implant capable of monitoring dopamine signals in the brain in real time in small animal models – an advance that could help improve our understanding of the role neurochemicals play in neurological disorders. The implant, which records dopamine activity in freely behaving subjects (without the need for bulky or prohibitive sensing equipment) includes a carbon nanotube-based sensor with sensitivities among the highest recorded so far.