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

Scientists from Rice University and Taif University (Taif, Saudi Arabia) have uncovered a property of ferroelectric two-dimensional materials that could be exploited as a feature in future devices. They have shown that because they bend in response to an electrical stimulus, single-layer ferroelectric materials can be controlled to act as a nanoscale switch or even a motor. "The novelty we found in this study is that there is a connection or coupling between the ferroelectric state and the bending or flexing of the material,” said Boris Yakobson, one of the authors of the study.

Researchers from the University of California Santa Cruz; the University of Manchester in the United Kingdom; and the International Center for Materials Nanoarchitectonics and National Institute for Materials Science in Tsukuba, Japan, have shown that trapped electrons traveling in circular loops at extreme speeds inside graphene quantum dots are highly sensitive to external magnetic fields and could be used as novel magnetic field sensors. Electrons in graphene (an atomically thin form of carbon) behave as if they were massless, and when these electrons are confined in a quantum dot, they travel at high velocity in circular loops around the edge of the dot. 

Researchers from Oregon State University and HP Inc. (Corvallis, Oregon) have developed a dual-purpose photocatalyst that purifies herbicide-tainted water while also producing hydrogen. Photocatalysts are materials that absorb light to reach a higher energy level and can use that energy to break down organic contaminants through oxidation. In this study, the researchers used titanium dioxide photocatalysts, which are derived from metal-organic frameworks – crystalline, porous materials with tunable structural properties and nanosized pores. 

Researchers from Stanford University and Pumpkinseed Technologies, Inc. (Palo Alto, CA) have developed an innovative method that could lead to faster, inexpensive, and more accurate microbial assays of virtually any fluid. The researchers modified an inkjet printer to print dots of blood that are two trillionths of a liter in volume – more than a billion times smaller than a raindrop. At that scale, the droplets are so small they may hold just a few dozen cells. The researchers infused the samples with gold nanorods that attach themselves to bacteria, if present. When laser light is shone on the tiny dots of blood, the gold nanorods act like antennas, drawing the laser light toward the bacteria and amplifying their signal some 1,500 times. 

Researchers from Mount Sinai Health System, Memorial Sloan Kettering Cancer Center, Nationwide Children’s Hospital/The Ohio State University, New York University Langone Medical Center, Weill Cornell Medicine, and Technion Israel Institute of Technology in Haifa, Israel, have developed a new drug delivery approach that uses nanoparticles to enable more effective and targeted delivery of anti-cancer drugs to treat brain tumors in children. To target their drug-loaded nanoparticles to the site of the disease – and not the normal brain regions – the researchers used a normal mechanism that the immune system uses to traffic white blood cells to sites of infection, inflammation, or tissue injury.  

The chemical environment of a tumor has a significant effect on how effective a particular treatment may be. For example, a low oxygen level in the tumor tissue impairs the effectiveness of radiation therapy. Now, a team of scientists from the University of Michigan, the University of Calabria (Rende, Italy), and the University of Padua (Padua, Italy) have demonstrated that an imaging system that uses special nanoparticles can provide a real-time, high-resolution chemical map that shows the distribution of chemicals of interest in a tumor. This imaging system could help clinicians make better recommendations on cancer therapy that is tailored to a particular patient.

One of the most expensive steps in manufacturing protein drugs – such as antibodies or insulin – is the purification step: isolating the protein from the bioreactor used to produce it. This step can account for up to half of the total cost of manufacturing a protein. In an effort to help reduce those costs, engineers at the Massachusetts Institute of Technology have devised a new way to perform this kind of purification. Their approach, which uses specialized nanoparticles to rapidly crystallize proteins, could help to make protein drugs more affordable and accessible, especially in developing countries.

Researchers from The Pennsylvania State University, the Weizmann Institute of Science in Rehovot, Israel, and the National Institute for Materials Science in Tsukuba, Japan, have developed a measurement technique to probe the proximity-induced superconductivity at the surface of a type of layered material called a heterostructure. Proximity-induced superconductivity is a mechanism to realize a topological superconductor, that is, a superconductor that holds its properties even after undergoing physical changes. The technique used by the researchers involves inserting a layer of graphene, which is a sheet of carbon atoms of one or two atoms thick, between a layer of a topological insulator material (bismuth antimony telluride) and a superconducting material layer (gallium).

Researchers at The University of Texas at Austin have partnered with Smart Material Solutions, Inc. (Raleigh, NC) to develop a new method to keep dust from sticking to surfaces. The result is the ability to make many types of materials dust-resistant, from spacecraft to solar panels to household windows. In experiments, the team changed the geometry of flat surfaces to create a tightly packed nanoscale network of pyramid-shaped structures. These sharp, angular structures make it difficult for dust particles to stick to the material, instead sticking to one another and rolling off the material via gravity.

Engineers at Caltech and the National Institute for Materials Science in Tsukuba, Japan, have discovered that when tungsten diselenide is placed on top of graphene bilayers, graphene's superconductivity is greatly improved. Notably, the superconducting critical temperature – that is, the warmest temperature at which the material can superconduct – is enhanced by a factor of 10. This finding provides new insight into the nature of superconductivity and suggests strategies for enhancing superconductivity in other related graphene-based materials.