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Category: nanotechnology – Page 226

One of the most difficult challenges in treating the brain cancer glioblastoma is that few drugs can pass through the blood-brain barrier. Scientists at Cedars-Sinai in Los Angeles have developed a system to circumvent this hurdle—one that combines a powerful immuno-oncology drug with a polymer-based delivery vehicle that can cross the blood-brain barrier.

The researchers showed that this “nano-immunotherapy” treatment crossed the blood-brain barrier in mouse models of glioblastoma, and that it stopped tumor cells from multiplying. They published their findings in the journal Nature Communications.

The Cedars-Sinai team used the polymer scaffold to deliver two types of immune checkpoint inhibitors, blocking either CTLA-4 or PD-1. When injected into the bloodstream of mice, the drugs quickly infiltrated brain tumors, but not healthy brain tissue, the researchers reported.

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Movies featuring heroes with superpowers, such as flight, X-ray vision or extraordinary strength, are all the rage. But while these popular characters are mere flights of fancy, scientists have used nanoparticles to confer a real superpower on ordinary mice: the ability to see near-infrared light. Today, scientists report progress in making versions of these nanoparticles that could someday give built-in night vision to humans.

The researchers will present their results at the American Chemical Society (ACS) Fall 2019 National Meeting & Exposition.

“When we look at the universe, we see only ,” says Gang Han, Ph.D., the project’s principal investigator, who is presenting the work at the meeting. “But if we had near-infrared vision, we could see the universe in a whole new way. We might be able to do infrared astronomy with the , or have without bulky equipment.”

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A gene called Lipocalin 2 is a major culprit in triple-negative breast cancer, an aggressive form of the disease for which there are few effective, targeted treatments. A team of researchers at Boston Children’s Hospital has developed an innovative way to knock out the gene using the editing system CRISPR and has shown its potential for treating triple-negative breast tumors in mice.

But to make CRISPR work in breast tumors, the researchers had to figure out a way to deliver the technology into breast cancer cells without using a virus or something else that might cause off-target side effects. So they encapsulated it in nanoparticles and targeted it at ICAM-1, a molecule expressed on breast cancer cells.

The encapsulated CRISPR system knocked out Lipocalin 2 with 81% efficiency in tumor samples, and when injected into mouse models of triple-negative breast cancer, it slowed tumor growth by 77%. The researchers reported the results in the journal Proceedings of the National Academy of Sciences.

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It’s not like the one in your car, but a team of physicists at Trinity College Dublin have built what they claim is the world’s smallest engine. The engine is the size of a single calcium ion — about ten billion times smaller than an automobile engine.

Rather than powering your next road trip, the atomic engine could one day be used to lay the foundation for extraordinary, futuristic nanotechnologies.

Here’s how it works: the calcium ion holds an electrical charge, which makes it spin. This angular momentum is then used to convert heat from a laser beam into vibrations.

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A research team led by the University of California San Diego has discovered the root cause of why lithium metal batteries fail—bits of lithium metal deposits break off from the surface of the anode during discharging and are trapped as “dead” or inactive lithium that the battery can no longer access.

The discovery, published Aug. 21 in Nature, challenges the conventional belief that fail because of the growth of a layer, called the solid interphase (SEI), between the anode and the electrolyte. The researchers made their discovery by developing a technique to measure the amounts of inactive lithium species on the anode—a first in the field of battery research—and studying their micro- and nanostructures.

The findings could pave the way for bringing rechargeable lithium batteries from the lab to the market.

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Self-assembled materials are attractive for next-generation materials, but their potential to assemble at the nanoscale and form nanostructures (cylinders, lamellae etc.) remains challenging. In a recent report, Xundu Feng and colleagues at the interdisciplinary departments of chemical and environmental engineering, biomolecular engineering, chemistry and the center for advanced low-dimension materials in the U.S., France, Japan and China, proposed and demonstrated a new approach to prevent the existing challenges. In the study, they explored size-selective transport in the water-continuous medium of a nanostructured polymer template formed using a self-assembled lyotropic H1 (hexagonal cylindrical shaped) mesophase (a state of matter between liquid and solid). They optimized the mesophase composition to facilitate high-fidelity retention of the H1 structure on photoinduced crosslinking.

The resulting nanostructured polymer material was mechanically robust with internally and externally crosslinked nanofibrils surrounded by a continuous aqueous medium. The research team fabricated a with size selectivity at the 1 to 2 nm length scale and water permeabilities of ~10 liters m−2 hour−1 bar−1 μm. The membranes displayed excellent anti-microbial properties for practical use. The results are now published on Science Advances and represent a breakthrough for the potential use of self-assembled membrane-based nanofiltration in practical applications of water purification.

Membrane separation for filtration is widely used in diverse technical applications, including seawater desalination, gas separation, food processing, fuel cells and the emerging fields of sustainable power generation and distillation. During nanofiltration, dissolved or suspended solutes ranging from 1 to 10 nm in size can be removed. New nanofiltration membranes are of particular interest for low-cost treatment of wastewaters to remove organic contaminants including pesticides and metabolites of pharmaceutical drugs. State-of-the-art membranes presently suffer from a trade-off between permeability and selectivity where increased permeability can result in decreased selectivity and vice-versa. Since the trade-off originated from the intrinsic structural limits of conventional membranes, materials scientists have incorporated self-assembled materials as an attractive solution to realize highly selective separation without compromising permeability.

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Researchers have developed artificial ‘chameleon skin’ that changes color when exposed to light and could be used in applications such as active camouflage and large-scale dynamic displays.

The material, developed by researchers from the University of Cambridge, is made of tiny particles of gold coated in a polymer shell, and then squeezed into microdroplets of water in oil. When exposed to heat or , the particles stick together, changing the color of the material. The results are reported in the journal Advanced Optical Materials.

In nature, animals such as chameleons and cuttlefish are able to change color thanks to chromatophores: skin cells with contractile fibers that move pigments around. The pigments are spread out to show their color, or squeezed together to make the cell clear.

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Thin, flexible fibers made of carbon nanotubes have now proven able to bridge damaged heart tissues and deliver the electrical signals needed to keep those hearts beating.

Scientists at Texas Heart Institute (THI) report they have used those biocompatible fibers in studies that showed sewing them directly into damaged tissue can restore electrical function to hearts.

“Instead of shocking and defibrillating, we are actually correcting diseased conduction of the largest major pumping chamber of the by creating a bridge to bypass and conduct over a scarred area of a damaged heart,” said Dr. Mehdi Razavi, a cardiologist and director of Electrophysiology Clinical Research and Innovations at THI, who co-led the study with Rice chemical and biomolecular engineer Matteo Pasquali.

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At human scale, controlling temperature is a straightforward concept. Turtles sun themselves to keep warm. To cool a pie fresh from the oven, place it on a room-temperature countertop.

At the nanoscale—at distances less than 1/100th the width of the thinnest human hair—controlling temperature is much more difficult. Nanoscale distances are so small that objects easily become thermally coupled: If one object heats up to a certain temperature, so does its neighbor.

When scientists use a as that , there is an additional challenge: Thanks to heat diffusion, materials in the beam path heat up to approximately the same temperature, making it difficult to manipulate the thermal profiles of objects within the beam. Scientists have never been able to use light alone to actively shape and control thermal landscapes at the nanoscale.

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