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

Researchers led by biomedical engineers at Tufts University have invented a microfluidic chip containing cardiac cells that can mimic hypoxic conditions following a heart attack. The chip contains multiplexed arrays of electronic sensors placed outside and inside the cells. After reducing levels of oxygen in the fluid within the device, the sensors detect an initial period of accelerated beat rate, followed by a reduction in beat rate and eventually arrhythmia which mimics cardiac arrest. The biosensor technology used in the microfluidic chip combines multi-electrode arrays that can provide extracellular readouts of voltage patterns, with nanopillar probes that enter the membrane to take readouts of voltage levels within each cell.

Researchers in the cancer nanomedicine community debate whether use of nanoparticles can best deliver drug therapy to tumors passively – allowing the nanoparticles to diffuse into tumors and become held in place – or actively, by adding an anti-cancer molecule that would bind to specific cancer cell receptors and, in theory, keep the nanoparticles in the tumor longer. Now, researchers at the Johns Hopkins Kimmel Cancer Center have found that nanoparticles coated with trastuzumab, a drug sold under the name Herceptin that targets breast cancer cells, were better retained in tumors than plain nanoparticles. The researchers also found that immune cells exposed to nanoparticles induced an anti-cancer immune response by activating T cells, which invaded tumors and slowed tumor growth.

Researchers in the cancer nanomedicine community debate whether use of nanoparticles can best deliver drug therapy to tumors passively – allowing the nanoparticles to diffuse into tumors and become held in place – or actively, by adding an anti-cancer molecule that would bind to specific cancer cell receptors and, in theory, keep the nanoparticles in the tumor longer. Now, researchers at the Johns Hopkins Kimmel Cancer Center have found that nanoparticles coated with trastuzumab, a drug sold under the name Herceptin that targets breast cancer cells, were better retained in tumors than plain nanoparticles. The researchers also found that immune cells exposed to nanoparticles induced an anti-cancer immune response by activating T cells, which invaded tumors and slowed tumor growth.

Graphene-based biosensors could usher in an era of liquid biopsy, detecting DNA cancer markers circulating in a patient's blood or serum. But current designs need a lot of DNA. In a new study, researchers at the University of Illinois at Urbana-Champaign have found that crumpling graphene makes it more than 10,000 times more sensitive to DNA by creating electrical "hot spots."

Graphene-based biosensors could usher in an era of liquid biopsy, detecting DNA cancer markers circulating in a patient's blood or serum. But current designs need a lot of DNA. In a new study, researchers at the University of Illinois at Urbana-Champaign have found that crumpling graphene makes it more than 10,000 times more sensitive to DNA by creating electrical "hot spots."

Scientists have discovered a new method for creating hollow metallic nanostructures with regularly spaced and sized pores. They used advanced electron tomography to collect three-dimensional images at different stages of synthesis. The images allowed the scientists to track the transition from gold nanocubes, with sharp corners, to gold-silver alloy nanowrappers, with pores at their corners. The pores are large and regular enough to hold drug-carrying nanoparticles.

Scientists have discovered a new method for creating hollow metallic nanostructures with regularly spaced and sized pores. They used advanced electron tomography to collect three-dimensional images at different stages of synthesis. The images allowed the scientists to track the transition from gold nanocubes, with sharp corners, to gold-silver alloy nanowrappers, with pores at their corners. The pores are large and regular enough to hold drug-carrying nanoparticles.

Replacing precious metal catalysts with those based on more abundant metals such as iron would significantly decrease their cost. But iron catalysts, while highly efficient, tend to quickly deactivate. Creating structures with iron that are active enough to promote the reaction without becoming deactivated could open the door to using these catalysts in practical applications. Researchers at the U.S. Department of Energy’s Brookhaven National Laboratory found a structure that might be able to do just that. They prepared a thin layer of iron oxide nanoparticles on top of a gold surface and discovered that dislocation lines appearing on the iron oxide surface are very active and are not deactivated.

Replacing precious metal catalysts with those based on more abundant metals such as iron would significantly decrease their cost. But iron catalysts, while highly efficient, tend to quickly deactivate. Creating structures with iron that are active enough to promote the reaction without becoming deactivated could open the door to using these catalysts in practical applications. Researchers at the U.S. Department of Energy’s Brookhaven National Laboratory found a structure that might be able to do just that. They prepared a thin layer of iron oxide nanoparticles on top of a gold surface and discovered that dislocation lines appearing on the iron oxide surface are very active and are not deactivated.

Researchers at Duke University and Michigan State University have engineered a novel type of supercapacitor that remains fully functional even when stretched to eight times its original size. It does not exhibit any wear and tear from being stretched repeatedly and loses only a few percentage points of energy performance after 10,000 cycles of charging and discharging. To make the stretchable supercapacitors, the researchers first grew a carbon nanotube forest—a patch of millions of nanotubes just 15 nanometers in diameter and 20-30 micrometers in length—on top of a silicon wafer. The researchers then coated a thin layer of gold nanofilm on top of the carbon nanotube forest.