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

Researchers at the U.S. Department of Energy’s Sandia National Laboratories have combined earlier work on painless microneedles with nanoscale sensors to create a wearable sensor patch that can continuously monitor the levels of an antibiotic called vancomycin. Continuous monitoring is crucial for vancomycin, because there is a narrow range within which it effectively kills bacteria without harming the patient, said Alex Downs, one of the scientists involved in this study.

Caltech researchers have developed a wearable sensor that monitors estradiol by detecting its presence in sweat. Estradiol is a hormone that is necessary for the development of secondary sexual characteristics in women and regulates their reproductive cycles. The sensor is built on a flexible plastic membrane; has tiny etched passages for channeling small amounts of sweat into the sensor; and is made with inkjet-printed gold nanoparticles and titanium carbide films (known as MXenes) that give the sensor a large surface area and electrical conductivity to increase its sensitivity.

Researchers from the University of Illinois Urbana-Champaign and the University of California, Irvine, have discovered that the friction on a graphene surface can be dynamically tuned using external electric fields. Surfaces coated in graphene films generally exhibit very low friction, but the new results demonstrate that friction on graphene-coated surfaces can be "turned on" by exposing the surface to an electric field under the proper conditions. The system can then be switched back to lower friction without applying large electrical biases between the surfaces in contact.

Researchers at the National Institute of Standards and Technology are working on an ambitious project, called Thermal Magnetic Imaging and Control (Thermal MagIC), that measures the magnetic responses of nanometer-sized spheres embedded in the object whose temperature is being measured. Thermal MagIC consists of two systems working together. The first part consists of the sensors themselves: nanometer-sized spheres whose magnetic signals change with temperature. The second part is the instrument that excites the tiny spheres magnetically and then reads out their signal.

Engineers at the University of California, San Diego, have developed nanoparticles, fashioned from plant viruses, that can deliver pesticide molecules to soil depths that were previously unreachable. This advance could potentially help farmers effectively combat parasitic nematodes that plague the root zones of crops while minimizing costs, pesticide use, and environmental toxicity. "We're developing a precision farming approach where we're creating nanoparticles for targeted pesticide delivery," said Nicole Steinmetz, the scientist leading this research effort.

Researchers from the University of Illinois at Urbana-Champaign and the University of Nebraska─Lincoln have developed a method of "wiring up" graphene nanoribbons, a class of one-dimensional materials that are of interest in the scaling of microelectronic devices. Using a direct-write scanning tunneling microscopy-based process, the nanometer-scale metal contacts were fabricated on individual graphene nanoribbons and could control their electronic character. The researchers say that this is the first demonstration of making metal contacts to specific graphene nanoribbons with certainty.

Researchers from Vanderbilt University Medical Center; the University of California, San Francisco; and the U.S. Department of Energy’s Lawrence Livermore National Laboratory have developed a new type of filter for kidney dialysis machines that can clean the blood more efficiently and improve patient care. The new filter uses carbon nanotubes – tiny tubes formed by a sheet of carbon atoms bonded in a hexagonal honeycomb mesh structure – that have very small, smooth channels. These channels make it easier to remove toxins and waste from the blood without letting important proteins escape, which can be a problem with traditional filters.

Late last year, researchers from Caltech revealed that they had developed a new fabrication technique for printing microsized metal parts containing features about as thick as three or four sheets of paper. Now, the Caltech team, along with researchers from the Agency for Science, Technology, and Research in Singapore, have reinvented the technique to allow for printing objects that are 150 nanometers in size. In doing so, the researchers also discovered that these objects can be three-to-five-times stronger than similarly sized structures.

Penn State researchers have developed a novel ultrasound imaging technique to view immune cells, called macrophages, continuously in mammal tissue. The researchers introduced nanoemulsion droplets to macrophages, which internalized them. A nanoemulsion is a mixture of oil droplets that are a few nanometers in diameter each. Under ultrasound, the nanoemulsion droplets turned into gas bubbles that helped to distinguish macrophages from other neighboring cells. 

Researchers from Caltech have created a new kind of drug delivery system that, they say, may give doctors the ability to treat cancer in a more targeted way. The system uses drugs that are activated by ultrasound only where they are needed in the body. The researchers combined air-filled protein nanostructures (found in some bacteria) and mechanophores (molecules that undergo a chemical change when subjected to a physical force).