(Funded by the U.S. Department of Defense)
Researchers from The University of Texas at Dallas; Texas State University in San Marcos, TX; and Lintec of America in Plano, TX, as well as international collaborators, have invented a new, inexpensive method in which fibers are coiled to make springlike artificial muscles. What’s unique about this method is that it doesn’t make use of a mandrel – a spindle that serves to support or shape the artificial muscles. The mandrel-free fabrication process involves inserting twist into individual fibers, causing them to coil back on themselves, and then plying the twisted fibers to create springlike coils. The researchers used the mandrel-free method to make high-spring-index carbon nanotube yarns, which could be used to harvest mechanical energy or as self-powered strain sensors.

(Funded by the U.S. National Science Foundation)
In a Perspective article published in Nature Materials, two engineers at the Massachusetts Institute of Technology, Carlos Portela and James Surjadi, discuss key hurdles, opportunities, and future applications in the field of mechanical metamaterials. Metamaterials are artificially structured materials with properties not easily found in nature. With engineered three-dimensional geometries at the micro- and nanoscale, metamaterials achieve unique mechanical and physical properties with capabilities beyond those of conventional materials. Over the past decade, metamaterials have emerged as a promising way to address engineering challenges for which other existing materials have lacked success.

(Funded by the National Institutes of Health)
Researchers from the California NanoSystems Institute at the University of California, Los Angeles, have developed a sensor technology based on natural biochemical processes that can continuously and reliably measure multiple metabolites at once. The sensors are built onto electrodes made of tiny cylinders called single-wall carbon nanotubes. These electrodes use enzymes and other molecules to perform reactions that mirror the body’s metabolic processes. Depending on the target metabolite, the sensors either detect it directly or first convert it into a detectable form through a chain of intermediary enzymatic reactions. The team measured metabolites in sweat and saliva samples from patients receiving treatment for epilepsy and detected a gut bacteria-derived metabolite in the brain that could cause neurological disorders if it accumulates.

(Funded by the National Institutes of Health)
Researchers at the University of Pennsylvania have developed a new process that transports DNA into cells using lipid nanoparticles. Unlike messenger RNA (mRNA), DNA remains active in cells for months, or even years, and can be programmed to work only in targeted cells. But past attempts to use lipid nanoparticles to deliver DNA failed, because DNA can trigger severe immune reactions. The researchers discovered that by adding a natural anti-inflammatory molecule, called nitro-oleic acid, to the lipid nanoparticles, these immune reactions could be eliminated. With this advancement, treated cells produced intended therapeutic proteins for about six months from a single dose – much longer than the few hours seen with mRNA therapies.

(Funded by the U.S. Department of Energy)
Stacking single layers of sub-nanometer-thick semiconductor materials, known as transition metal dichalcogenides, can generate a moiré potential – a “seascape” of potential energy with regularly repeating peaks and valleys. These peaks and valleys were previously thought to be stationary, but now, researchers from the Molecular Foundry, a user facility at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory, and the University of California, Berkeley, along with international collaborators, have shown that the moiré potentials that emerge when transition metal dichalcogenides are stacked are constantly moving, even at low temperatures. Their discovery contributes to foundational knowledge in materials science and holds promise for advancing the stability of quantum technologies, because controlling moiré potentials could help mitigate decoherence in qubits and sensors. (Decoherence occurs when interference causes the quantum state and its information to be lost.)