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Category: nanotechnology – Page 22

Structures of hantavirus glycoprotein tetramers

This surface protein complex for the Andes virus is a mushroom-shaped structure called a Gn-Gc tetramer. To map the 3D structures, the team first produced virus-like particles that mimic a real virus, but without the genome that makes a virus infectious. They then used a cryo-electron microscope—which shines an electron beam through a frozen sample and detects the shadows created by molecules—to reconstruct the three-dimensional structures of the Gn-Gc tetramers on the surface of the virus-like particles.

But there was a twist: To obtain extremely high-resolution structures, the researchers painstakingly identified and isolated shadows from only the tetramers that were pointing sidewise relative to the electron beam and ignored those pointing in other directions. This allowed them to borrow a reconstruction method typically used on individual proteins.

The resulting structures have an extremely high resolution of 2.3 angstroms, meaning details the size of just a couple of atoms were effectively captured. That’s enough to represent a transformational improvement over another team’s model of the tetramer from a few years ago, at a resolution of 12 angstroms, still tiny but large enough to produce some key inaccuracies – ones effectively corrected with the newer method and resulting structure.

These latest structures show the Gn-Gc tetramer in a particular state before it has infected a cell. For vaccines or antibody therapies to be most effective against a hantavirus, mimicking surface proteins at this pre-infection stage is essential. ScienceMission sciencenewshighlights.

Hantaviruses, transmitted from rodents to people, have a death rate approaching 40%. They’re found around the world, and because there are no approved vaccines or treatments, they’re among the pathogens of highest concern for future pandemics. They made news in the United States last year when Betsy Arakawa, the wife of actor Gene Hackman, died from a hantavirus infection in New Mexico in March.

New findings published in the journal Cell about the Andes virus, a hantavirus endemic to the southwestern U.S. and other parts of North and South America, represent a crucial first step towards much-needed vaccines and antibody therapies for this and other hantaviruses.

Continue reading “Structures of hantavirus glycoprotein tetramers” | >

Size-shifting nanoparticles successfully deliver mRNA medicine to the pancreas

In recent years, mRNA in lipid nanoparticles (mRNA–LNPs) has emerged as a promising strategy for treating numerous conditions, including COVID-19, various cancers and chronic genetic disorders. To date, this technology has not been successfully used for pancreatic diseases, but that could be about to change. In a paper published in Nature, scientists from China report the development of a new lipid nanoparticle drug-delivery system specifically designed for the pancreas.

Lipid nanoparticles are a special class of fat-based carriers that encapsulate and deliver nucleic acids such as messenger RNA into cells. Among the reasons they have not worked for the pancreas until now is that most LNPs naturally accumulate in the liver and spleen. That means the therapeutic molecules they carry can’t accumulate to high enough levels to be beneficial.

However, the research team realized that while the liver and spleen are wrapped in a dense, protective outer layer called a capsule, the pancreas is only covered by a thin layer of connective tissue. They wondered if these organ capsules act as a biological filter. If so, they could perhaps design nanoparticles large enough to be physically blocked by the walls of the spleen and liver, leaving the pancreas as the only place to go. They named this discovery the capsule-filter-mediated pancreatic-targeted (CAMP) mechanism.

Metasurface-based SLM could enhance AR, VR and LiDAR performance

Many cutting-edge technologies, ranging from augmented reality (AR) and virtual reality (VR) to LiDAR (light detection and ranging) systems, rely on components that enable the precise control of light. These components include so-called spatial light modulators (SLMs), systems that dynamically adjust the position of a light wave within its cycle (i.e., phase), as well as its amplitude or direction across several pixels.

Conventional SLMs rely on liquid crystals, materials in a state of matter at the intersection between solid and liquid. While these components are widely used, they typically struggle to reach the speed and pixel density required to create high-quality three-dimensional (3D) images known as holographs.

Researchers at Huazhong University of Science and Technology and other institutes recently developed a new metasurface, an ultrathin and nano-engineered surface, that could be used to produce dynamic and high-quality holographic images in real time, with a remarkable definition. The new metasurface, introduced in a paper published in Nature Nanotechnology, was used to create a SLM that could be used to enhance the performance of AR, VR, and LiDAR technology.

Nano-cage removes up to 98% of PFAS in tap water tests

Contamination of ground, surface and drinking water by perfluoroalkyl and polyfluoroalkyl substances (PFAS) affects millions of people worldwide. A promising new method developed by Flinders University scientists paves the way to help remove the most difficult-to-capture variants of these persistent pollutants from water.

The research team, led by Flinders ARC Research Fellow Dr. Witold Bloch, has discovered adsorbents that effectively capture PFAS, including short-chain forms that are especially difficult to remove using existing technologies.

The study, published in the Angewandte Chemie International Edition, showcases the use of a nano-sized molecular cage that acts as a highly selective “PFAS trap.”

Nanoparticles for Targeted Drug Delivery to Cancer Stem Cells: A Review of Recent Advances

Cancer stem cells (CSCs) are a subpopulation of cells that can initiate, self-renew, and sustain tumor growth. CSCs are responsible for tumor metastasis, recurrence, and drug resistance in cancer therapy. CSCs reside within a niche maintained by multiple unique factors in the microenvironment. These factors include hypoxia, excessive levels of angiogenesis, a change of mitochondrial activity from aerobic aspiration to aerobic glycolysis, an upregulated expression of CSC biomarkers and stem cell signaling, and an elevated synthesis of the cytochromes P450 family of enzymes responsible for drug clearance. Antibodies and ligands targeting the unique factors that maintain the niche are utilized for the delivery of anticancer therapeutics to CSCs. In this regard, nanomaterials, specifically nanoparticles (NPs), are extremely useful as carriers for the delivery of anticancer agents to CSCs.

Lipid nanoparticle GM-CSF replacement for autoimmune pulmonary alveolar proteinosis

One of the most-viewed PNAS articles in the last week is “Lipid nanoparticle GM-CSF replacement for autoimmune pulmonary alveolar proteinosis.” Explore the article here: https://ow.ly/QMWH50Yl87H

For more trending articles, visit https://ow.ly/pmKX50Yl87I.

Granulocyte–macrophage colony-stimulating factor (GM-CSF) deficiency drives autoimmune pulmonary alveolar proteinosis (aPAP), a disease characterized by impaired macrophage-mediated clearance of pulmonary surfactants. Clinical data suggest that inhaled recombinant GM-CSF reduces symptoms in aPAP patients, providing a rationale for mRNA-based GM-CSF replacement therapies. However, these require effective mRNA delivery after nebulization. Here, we report the iterative in vivo design of a lipid nanoparticle, named nebulized lung delivery 2 (NLD2), that efficiently delivers mRNA after nebulization. NLD2 carrying GM-CSF mRNA transfected alveolar macrophages in vivo, leading to interleukin-10 pathway activation and subsequent surfactant lipoprotein clearance. In a preclinical disease model of aPAP, GM-CSF mRNA delivery reduced surfactant protein thickness more than recombinant GM-CSF. These data support continued exploration of nebulized lipid nanoparticle therapies for aPAP.

When light ‘thinks’ like the brain: The connection between photons and artificial memory

An international study has revealed a surprising connection between quantum physics and the theoretical models underlying artificial intelligence. The study results from a collaboration between the Institute of Nanotechnology of the National Research Council (Cnr-Nanotec), the Italian Institute of Technology (IIT), and Sapienza University of Rome, together with international research institutions. The research paper was published recently in the journal Physical Review Letters.

Italian researchers show that identical photons propagating within optical circuits spontaneously behave like a Hopfield Network, one of the best-known mathematical models used to describe the associative memory mechanisms of the human brain.

“Instead of using traditional electronic chips, we exploited quantum interference —the phenomenon that occurs in photonic chips when particles of light overlap and interact with one another to encode and retrieve information,” explains Marco Leonetti, coordinator and corresponding author of the study, senior researcher at Cnr-Nanotec and affiliated with the Center for Life Nano-and Neuro-Science at the Italian Institute of Technology (IIT) in Rome. “In this system, photons are not merely carriers of data, but themselves become the ‘neurons’ of an associative memory.”

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