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

Researchers from Penn State, Purdue University, Intel Corporation (Santa Clara, CA), The Kurt J. Lesker Company (Jefferson Hills, PA), and National Yang Ming Chiao Tung University in Taiwan have developed a process to produce a "rust-resistant" coating with additional properties ideal for creating faster, more durable electronics. Traditional methods to protect two-dimensional (2D) semiconductor materials from rusting involve oxide-based coatings, but these processes often use water, which can accelerate the oxidation they aim to prevent. The team's approach was to use amorphous boron nitride as a coating material, which was evenly coated on the 2D materials by using a new two-step atomic layer deposition method.

Researchers from New York University have begun to explore exosomes, tiny membrane-bound vesicles, as promising tools for wound healing. These nanovesicles carry various biological materials – nucleic acids, proteins, and lipids – allowing them to mediate intercellular communication and influence processes such as tissue repair. By combining them with hydrogels, which are composed of networks of cross-linked polymers, the researchers showed that hydrogel-exosome combinations consistently lead to faster wound closure than either hydrogels or exosomes used alone.

Using a ventilator-on-a-chip developed at The Ohio State University, researchers have found that shear stress from the collapse and reopening of the air sacs is the most harmful type of damage. This miniature organ-on-a-chip model simulates lung injury during mechanical ventilation, said Samir Ghadiali, one of the scientists involved in this study. The ventilator-on-a chip’s measurement of real-time changes to cells was enabled by an innovative approach: growing human lung cells on a synthetic nanofiber membrane mimicking the complex lung matrix. This ventilator-on-a-chip is closer to the authentic ventilated lung microenvironment than any similar lung chip systems to date, the researchers said.

Researchers from the University of Texas at Dallas and Vanderbilt University have found that X-rays of the kidneys using gold nanoparticles as a contrast agent might be more accurate in detecting kidney disease than standard laboratory blood tests. Based on their study in mice, the researchers also realized that caution may be warranted in using renal-clearable nanomedicines to patients with compromised kidneys. For example, they found that in mice with severely injured kidneys, nanoparticle transport through the kidneys was slowed down significantly, a situation that caused the nanoparticles to stay in the kidneys longer.

A key step toward reusing carbon dioxide to make sustainable fuels is chaining carbon atoms together, and an artificial photosynthesis system developed at the University of Michigan can bind two of them into hydrocarbons. The system produces ethylene – a hydrocarbon typically used in plastics – with efficiency, yield, and longevity above other artificial photosynthesis systems. The device absorbs light through two kinds of semiconductors: a forest of gallium nitride nanowires, each just 50 nanometers wide, and the silicon base on which they were grown. The reaction transforming water and carbon dioxide into ethylene takes place on copper clusters that dot the nanowires.

Researchers have developed an innovative nanofibrous membrane to remove microplastics from drinking water. Water filters on the market today can remove some contaminants, but they’re not designed to capture microplastics. The filter membrane is made from polyvinyl alcohol fibers, which are polymers currently used in biomedical applications. The team chose the material because it is low-cost and is not toxic to humans, animals, or plants. “The idea is to design a filter that can be attached to a faucet so it can remove microplastic and lead at the same time from tap water,” said Maryam Salehi, one of the researchers involved in this study. 

Researchers from the U.S. Department of Energy's Pacific Northwest National Laboratory and Lawrence Berkeley National Laboratory; the University of Washington; North Carolina State University; and Xiamen University in China have achieved a uniform two-dimensional (2D) layer of silk protein fragments on graphene, a carbon-based material useful for its excellent electrical conductivity. This combination of materials—silk-on-graphene—could form a sensitive, tunable transistor highly desired by the microelectronics industry for wearable and implantable health sensors. The researchers also see potential for their use as a key component of memory transistors or “memristors,” in computing neural networks. Memristors allow computers to mimic how the human brain functions. 

Researchers at the University of Minnesota and the University of Arizona have provided new insights into how next-generation electronics break down or degrade over time. Using a sophisticated electron microscope, the researchers looked at the nanopillars within magnetic tunnel junctions – the building blocks for the non-volatile memory in smart watches and in-memory computing. The researchers ran a current through the device to see how it operates. As they increased the current, they were able to observe how the device degrades and eventually dies in real time. “What was unusual with this discovery is that we observed this burn out at a much lower temperature than what previous research thought was possible,” said Andre Mkhoyan, one of the scientists involved in this research.

Researchers from the University of Pennsylvania have demonstrated a new kind of nanopore platform that consists of two or more nanopores stacked just nanometers apart, allowing for more precise detection and control of DNA as it wiggles through. “With current platforms, when molecules like DNA are placed near the nanopores, it’s sort of like having spaghetti in a pot—tangled and difficult to work with, let alone guiding through one hole,” explains Dimitri Monos, one of the scientists involved in this study. “So, typically, researchers need to use proteins to capture, unwind, and straighten it, which, while effective, has many limitations. But with this new design, we’re essentially guiding molecules through two coupled nanopores in the material, providing a controlled, smoother passage of molecules.”

The National Institute for Occupational Safety and Health’s Nanotechnology Research Center (NTRC) is celebrating its 20-year anniversary! Over the years, researchers at the NTRC have studied the #toxicity of many engineered nanomaterials throughout their life cycles. The research has covered primary manufactured forms (such as carbon nanotubes, nanoscale titanium dioxide, and silver nanoparticles) and modified versions for specific applications (such as silica-coated iron oxide, heat-treated carbon nanotubes, and reduced graphene oxide). Early studies focused on the tiniest components of air pollution, known as ultrafine particles, which laid the foundation for ongoing research efforts to assess two types of nanoparticles found in workplaces: engineered nanomaterials (purposely created for various applications) and process-derived nanoparticles (unintentionally produced during industrial processes). Also, using samples from worker health effects studies, researchers developed toxicology studies to determine biomarkers of exposure and disease. Together, these studies offer valuable data for understanding workplace hazards and risks.