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

Researchers at the University of Pittsburgh have developed silk iron microparticles and magnetic iron oxide nanoparticles and then chemically bonded the silk microparticles with the nanoparticles. The microparticles were designed to deliver drugs to sites in the body, and the drugs were towed by the microparticles like a trailer is towed by a car. “You can think of it like towing cargo – we created the [micro]particles to carry drugs, and the nanoparticles are the tow hook,” said Mostafa Bedewy, associate professor at the University of Pittsburgh. Now that the researchers have found a way to magnetically guide the silk microparticles with the nanoparticles, the next step will be to load them with therapeutic cargo. This research opens the door to a wide range of future applications – from targeted cancer therapies to regenerative treatments for cardiovascular disease. 

Researchers from the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California, Los Angeles, have created a heat pump that consists of stacked layers of electrocaloric materials, which temporarily change temperature in response to an electric field. Six polymer film discs, each about an inch in diameter and coated with carbon nanotubes, serve as a heat pump, moving warmth from the layer closest to the heat source away to the outermost layer. The nanotubes function as conductors for the electric field that stimulates the material. A proof of concept lowered ambient temperatures by 16 degrees Fahrenheit within 30 seconds, and readings at the edge of the device dipped as low as 25 degrees Fahrenheit. 

For more than 100 years, scientists have used a method called crystallography to determine the atomic structure of materials, but this technique only works well when researchers have large, pure crystals. For a powder of nanocrystals, the method only hints at the unseen structure. Now, scientists at Columbia Engineering have created a machine learning algorithm that can observe the pattern produced by a powder of nanocrystals to infer their atomic structures. The scientists began with a dataset of 40,000 crystal structures and jumbled their atomic positions until they were indistinguishable from random placement. Then, they trained a deep neural network to connect these almost randomly placed nanocrystals with their associated X-ray diffraction patterns. Lastly, the algorithm was able to determine the atomic structure from nanocrystals of various shapes in the powder.

Scientists at Lawrence Berkeley National Laboratory (Berkeley Lab) and SLAC National Accelerator Laboratory have revealed the fundamental mechanisms that limit the performance of copper nanocatalysts – critical components in chemical reactions that transform carbon dioxide and water into valuable fuels and chemicals. Copper’s catalytic properties quickly degrade during these reactions, diminishing its performance over time. The researchers identified and observed two competing mechanisms that drive the copper nanoparticles that make up the nanocatalysts to the brink of degradation: nanoparticle migration and coalescence, in which smaller particles combine into larger ones, and Ostwald ripening, where larger particles grow at the expense of smaller particles. These findings suggest mitigation strategies to protect the copper nanocatalysts by limiting either mechanism. Part of the research was conducted at the Molecular Foundry, a DOE Office of Science national user facility at Berkeley Lab.

Historically, the vast majority of pharmaceutical drugs have been designed down to the atomic level, so that the specific location of each atom within the drug molecule determines how well it works and how safe it is. Now, Northwestern University and Mass General Brigham scientists argue that this precise structural control should be applied to optimize new nanomedicines. The scientists cite three examples of trailblazing structural nanomedicines: spherical nucleic acids (globular form of DNA that can easily enter cells and bind to targets), chemoflares (smart nanostructures that release chemotherapeutic drugs in response to cues in cancer cells) and megamolecules (precisely assembled protein structures that mimic antibodies). 

Researchers from the University of Michigan and the Biointerfaces Institute (Ann Arbor, MI), along with international collaborators, have created nanodiscs that can target cholesterol levels in glioblastoma multiforme, an aggressive form of brain cancer, by starving the cancer cells and increasing survival rates of treated mice. The nanodiscs delivered molecules that increase the number of pumps that can export cholesterol out of tumor cells, resulting in their death. When used in combination with radiation therapy, more than 60% of the mice survived when compared to the mice that only received radiation. The nanodisks also had molecules on their surfaces that activate the body’s immune system. As a result, immune cells not only attacked the tumor but also were able to attack any future tumors.

Engineers at the Massachusetts Institute of Technology have found a way to create a metamaterial that is both strong and stretchy. (A metamaterial is a synthetic material with microscopic structures that give it exceptional properties.) The key to the new material’s dual properties is a combination of stiff microscopic struts and a softer woven architecture. The researchers printed samples of the new metamaterial, each measuring in size from several square microns to several square millimeters. They put the material through a series of stress tests, in which they attached either end of the sample to a specialized nanomechanical press and measured the force it took to pull the material apart. They found their new material was able to stretch three times its own length. The researchers say the new design can be applied to other materials and create stretchy ceramics, glass, and metals. This work was performed, in part, through the use of MIT.nano’s facilities. 

In 2023, researchers at Caltech developed a smart bandage that can provide real-time data about chronic wounds and accelerate the healing process by applying medication or electrical fields to stimulate tissue growth. Now, the researchers have shown that an improved version of their bandage can continually sample fluid, which the body sends to wound sites as part of the inflammatory response. The bandage is composed of a flexible, biocompatible polymer strip that integrates a nanoengineered biomarker sensor array, which is disposable for hygiene and single-use applications. The system also includes a reusable printed circuit board that handles signal processing and wireless data transmission to a user interface, such as a smartphone.

Researchers from the University of Illinois Urbana-Champaign, Purdue University, and the Chan Zuckerberg Biohub Chicago have created DNA origami structures – which are made by folding DNA into nanoscale scaffolds – that can selectively deliver fluorescent imaging agents to pancreatic cancer cells without affecting normal cells. The team experimented with different sizes of tube- and tile-shaped DNA origami structures. They found that tube-shaped structures about 70 nanometers in length and 30 nanometers in diameter, as well as ones that are about 6 nanometers in length and 30 nanometers in diameter, experienced the greatest uptake by the pancreatic cancer tissue while not being absorbed by the surrounding, noncancerous tissue. Larger tube-shaped structures and all sizes of tile-shaped structures did not perform as well.

Researchers have long recognized that quantum communication systems would transmit quantum information better and be unaffected by certain forms of error if nonlinear optical processes were used. But past efforts at using such processes could not operate with the very low light levels required for quantum communication. Now, researchers at the University of Illinois Urbana-Champaign have improved the technology by basing the nonlinear process on an indium-gallium-phosphide nanophotonic platform. The result requires much less light and operates all the way down to single photons, the smallest units of light.