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

A major challenge in self-powered wearable sensors for health care monitoring is distinguishing different signals when they occur at the same time. Now, researchers from Penn State and Hebei University of Technology in China have addressed this issue by developing a new type of flexible sensor that can accurately measure both temperature and physical strain simultaneously but separately, potentially enabling better wound healing monitoring. The sensor is made with laser-induced graphene, which forms when a laser heats certain carbon-rich materials in a way that converts their surface into a graphene structure. 

Physicists from the Massachusetts Institute of Technology, Harvard University, and the National Institute for Materials Science in Tsukuba, Japan, have directly measured superfluid stiffness for the first time in "magic-angle" graphene – materials that are made from two or more atomically thin sheets of graphene twisted with respect to each other at just the right angle. The twisted structure exhibits superconductivity, in which electrons pair up, rather than repelling each other as they do in everyday materials. These so-called Cooper pairs can form a superfluid, with the potential to move through a material as an effortless, friction-free current. "But even though Cooper pairs have no resistance, you have to apply some push, in the form of an electric field, to get the current to move," says Joel Wang, one of the scientists involved in this study. "Superfluid stiffness refers to how easy it is to get these particles to move, in order to drive superconductivity." 

Researchers from Northwestern University have defined a method to tailor a sponge that is coated with nanoparticles to specific Chicago pollutants and then to selectively release them. In its first iteration, the sponge platform was made of polyurethane and coated with a substance that attracted oil and repelled water. The newest version is a highly hydrophilic (water-loving) cellulose sponge coated with nanoparticles tailored to other pollutants. The scientists found that by lowering the pH, metals flush out of the sponge. Once copper and zinc are removed, the pH is then raised, at which point phosphate comes off the sponge. Even after five cycles of collecting and removing minerals, the sponge worked just as well, and the resulting water had untraceable amounts of pollutants.

Researchers from the University of California, Berkeley; the U.S. Department of Energy’s Lawrence Berkeley National Laboratory; and the University of Cambridge have developed a practical way to make hydrocarbons – molecules made of carbon and hydrogen – powered solely by the sun. The device combines a light absorbing “leaf” made from a high-efficiency solar cell material called perovskite, with a flower-shaped copper nanocatalyst, to convert carbon dioxide into useful molecules. Unlike most metal catalysts, which can only convert carbon dioxide into single-carbon molecules, the copper flowers enable the formation of more complex hydrocarbons with two carbon atoms, such as ethane and ethylene, which are key building blocks for liquid fuels, chemicals, and plastics.

Researchers from Caltech; the Beckman Research Institute at City of Hope in Duarte, CA; and the University of California, Los Angeles, have developed a technique for inkjet-printing arrays of special nanoparticles that enables the mass production of long-lasting wearable sweat sensors. These sensors could be used to monitor a variety of biomarkers – such as vitamins, hormones, metabolites, and medications – in real time, providing patients and their physicians with the ability to continually follow changes in the levels of those molecules. Wearable biosensors that incorporate the new nanoparticles have been successfully used to monitor metabolites in patients suffering from long COVID and the levels of chemotherapy drugs in cancer patients at City of Hope. "There are many chronic conditions and their biomarkers that these sensors now give us the possibility to monitor continuously and noninvasively," says Wei Gao, one of the researchers involved in this study.

Scientists from the University of Virginia, the University of Wisconsin-Madison, The Ohio State University, Northwestern University, the University of Tokyo, and the Sakakibara Heart Institute in Tokyo have developed a nanotechnology-based drug delivery system to save patients from repeated surgeries. The approach would allow surgeons to apply a paste of nanoparticles containing hydrogel on transplanted veins to prevent the formation of harmful blockages inside the veins. Not only did this innovation, dubbed "Pericelle," work at three months – when the applied drug supply ran out – but it continued to work at six months and was still working at nine months. The scientists can't fully explain the unexpectedly durable benefits, but they are excited about what it suggests for the potential of their technique. 

Researchers from the University at Buffalo; Central South University in Changsha, China; Shandong Normal University in Jinan, China; TU Wien in Vienna, Austria; the University of Salerno in Italy; and Sungkyunkwan University in Suwon, South Korea, have demonstrated that using thin two-dimensional (2D) materials, like the semiconductor molybdenum disulfide (MoS2), in combination with silicon can create highly efficient electronic devices with excellent control over how an electrical charge is injected and transported. The presence of the 2D material between the metal and silicon – despite the MoS2 being less than one nanometer thick – can change how electrical charges flow. “Our work investigates how emerging 2D materials can be integrated with existing silicon technology to enhance functionality and improve performance, paving the way for energy-efficient nanoelectronics,” says Huamin Li, the study’s lead author. 

Researchers from the University of California, Davis, have developed a new technique to trap clusters of platinum atoms in nanoscale islands. Previous work had shown that platinum arranged in clusters of a few atoms on a surface makes a better hydrogenation catalyst than either single platinum atoms or larger nanoparticles of platinum. But such small clusters tend to clump easily into larger particles, losing efficiency. So, the researchers decided to "trap" platinum clusters on a tiny island of cerium oxide supported on a silica surface and noticed that such clusters showed good catalytic activity in hydrogenation of ethylene.

A few years ago, researchers at Carnegie Mellon University made an intriguing discovery: adding a branch to the end of lipid nanoparticles' normally linear lipid tails dramatically improved messenger RNA (mRNA) delivery. Now, researchers at the University of Pennsylvania have tested branched lipids in a variety of experiments and found that these lipids reliably outperform even the lipid nanoparticles used by Moderna and Pfizer/BioNTech, the makers of the COVID-19 vaccines. The researchers hope the branched lipids will not only improve lipid nanoparticle delivery but also inspire a new approach to designing lipids, moving away from trial-and-error methods.

Researchers at Penn State have developed novel contrast agents that target two proteins implicated in osteoarthritis, a degenerative joint disease. By marking the proteins with the contrast agents, which comprise newly designed metal nanoprobes, the researchers can use advanced imaging, called photon-counting computed tomography, to simultaneously track separate biological processes in color, which, together, reveal more about the disease’s progression than a traditional scan. “This high-resolution … imaging approach could potentially be used to image multiple biological targets, thus enabling disease progression tracking over time,” said Dipanjan Pan, one of the scientists involved in this study. Read additional details about the research here: https://www.psu.edu/news/research/story/new-technique-allows-technicolor-imaging-degenerative-joint-disease.