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

Researchers from the U.S. Department of Energy’s Argonne National Laboratory and Fermi National Accelerator Laboratory, as well as Northern Illinois University have discovered that superconducting nanowire photon detectors, which are used for detecting photons (the fundamental particles of light) could potentially also function as highly accurate particle detectors, specifically for high-energy protons used as projectiles in particle accelerators. The ability to detect high-energy protons with superconducting nanowire photon detectors has never been reported before, and this discovery widens the scope of particle detection applications.

Researchers from Rutgers University, the New Jersey Institute of Technology, the Connecticut Agricultural Experiment Station in New Haven, CT, and the Environmental and Occupational Health Sciences Institute in Piscataway, NJ, have shown that microplastic and nanosplastic particles in soil and water can significantly increase how much toxic chemicals plants and human intestinal cells absorb. Using a cellular model of the human small intestine, the researchers found that nano-size plastic particles increased the absorption of arsenic by nearly six-fold compared with arsenic exposure alone. The same effect was seen with boscalid, a commonly used pesticide. Also, the researchers exposed lettuce plants to two sizes of polystyrene particles – 20 nanometers and 1,000 nanometers – along with arsenic and boscalid. They found the smaller particles had the biggest impact, increasing arsenic uptake into edible plant tissues nearly threefold compared to plants exposed to arsenic alone.

Researchers from Rice University, the University of California Berkeley, the University of Pennsylvania, and the Massachusetts Institute of Technology have shed light on how the extreme miniaturization of thin films affects the behavior of relaxor ferroelectrics — materials with noteworthy energy-conversion properties used in sensors, actuators, and nanoelectronics. The findings reveal that as the films shrink to dimensions comparable to internal polarization structures within the films, their fundamental properties can shift in unexpected ways. More specifically, when the films are shrunk down to a precise range of 25–30 nanometers, their ability to maintain their structure and functionality under varying conditions is significantly enhanced.

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.