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Ideally, the nanopore dimensions should be comparable to those of the analyte for the presence of the analyte to produce a measurable change in the ionic current amplitude above the noise level. Nanopores can be formed in several ways, with a wide range of pore diameters. Biological nanopores are formed by the self-assembly of either protein subunits, peptides or even DNA scaffolds in lipid bilayers or block copolymer membranes^1,3,6,17,18. They possess atomically precise dimensions controlled by biopolymer sequences, providing the ability to recognize biomolecules with constriction diameters of ~1–10 nm. Solid-state nanopores are crafted in thin inorganic or plastic membranes (for example, SiN_x), which allows the nanopores to have extended diameters of up to hundreds of nanometres, permitting the entry or analysis of large biomolecules and complexes. The tools for fabricating solid-state nanopores, which include electron/ion milling^4,5, laser-based optical etching^19,20 and the dielectric breakdown of ultrathin solid membranes^21,22, can be used to manipulate nanopore size at the nanometre scale, but allow only limited control over the surface structure at the atomic level in contrast to biological nanopores. The chemical modification and genetic engineering of biological nanopores, or the introduction of biomolecules to functionalize solid-state nanopores²³, can further enhance the interactions between a nanopore and analytes, improving the overall sensitivity and selectivity of the device^{2,17,24,25,26}. This feature allows nanopores to controllably capture, identify and transport a wide variety of molecules and ions from bulk solution.

Nanopore technology was initially developed for the practicable stochastic sensing of ions and small molecules^2,27,28. Subsequently, many developmental efforts were focused on DNA sequencing^1,7,8,9. Now, however, nanopore applications extend well beyond sequencing, as the methodology has been adapted to analyse molecular heterogeneities and stochastic processes in many different biochemical systems (Fig. 1). First, a key advantage of nanopores lies in their ability to successively capture many single molecules one after the other at a relatively high rate, which allows nanopores to explore large populations of molecules at the single-molecule level in reasonable timeframes. Second, nanopores essentially convert the structural and chemical properties of the analytes into a measurable ionic current signal, even achieving enantiomer discrimination²⁹. The technology can be used to report on multiple molecular features while circumventing the need for labelling chemistries, which may complicate the overall analysis process and affect the molecular structures. For example, nanopores can discriminate nearly 13 different amino acids in a label-free manner, including some with minute structural differences³⁰. An important aspect is the ability of nanopores to identify species³¹ that lack suitable labels for signal amplification or whose information is hidden in the noise of analytical devices. Consequently, nanopores may serve well in molecular diagnostic applications required for precision medicine, which achieves the identification of nucleic acid, protein or metabolite analytes and other biomarkers^{11,32,33,34,35}. Third, nanopores provide a well-defined scaffold for controllably designing and constructing biomimetic systems, which involve a complex network of biomolecular interactions. These nanopore systems track the binding dynamics of transported biomolecules as they interact with nanopore surfaces, hence serving as a platform for unravelling complex biological processes (for example, the transport properties of nuclear pore complexes)^36,37,38,39. Fourth, chemical groups can be spatially aligned within a protein nanopore, providing a confined chemical environment for site-selective or regioselective covalent chemistry. This strategy has been used to engineer protein nanoreactors to monitor bond-breaking and bond-making events^40,41.

Here we discuss the latest advances in nanopore technologies beyond DNA sequencing and the future trajectory of the field, as well as the opportunities and main challenges for the next decade. We specifically address the emerging nanopore methods for protein analysis and protein sequencing, single-molecule covalent chemistry, single-molecule analysis of clinical samples and insights into the use of biomimetic pores for analysing complex biological processes.

The new material is far superior to today’s non-stick options.

Researchers at Tufts University have developed a method for developing silk-based materials that refuse to stick to water and exhibit non-stick properties that surpass those of current non-stick surfaces, according to a press release by the institution published on Friday.

“The success we had with modifying silk to repel water extends our successes with chemically modifying silk for other functionalities—such as the ability to change color, conduct electrical charge, or persist or degrade in a biological environment,” said David Kaplan, Stern Family Professor of Engineering at Tufts.

Continue reading “Scientists break down silk to invent extremely efficient non-stick material” »

Skoltech scientists modeled the behavior of nanobubbles appearing in van der Waals heterostructures and the behavior of substances trapped inside the bubbles. In the future, the new model will help obtain equations of state for substances in nano-volumes, opening up new opportunities for the extraction of hydrocarbons from rock with large amounts of micro-and nanopores. The results of the study were published in the Journal of Chemical Physics.

The van der Waals nanostructures hold much promise for the study of tiniest samples with volumes from 1 cubic micron down to several cubic nanometers. These atomically thin layers of two-dimensional materials, such as graphene, hexagonal boron nitride (hBN) and dichalcogenides of transition metals, are held together by weak van der Waals interaction only. Inserting a sample between the layers separates the upper and bottom layers, making the upper layer lift to form a nanobubble. The resulting structure will then become available for transmission electron and atomic force microscopy, providing an insight into the structure of the substance inside the bubble.

The properties exhibited by substances inside the van der Waals nanobubbles are quite unusual. For example, water trapped inside a nanobubble displays a tenfold decrease in its dielectric constant and etches the diamond surface, something it would never do under normal conditions. Argon which typically exists in liquid form when in large quantities can become solid at the same pressure if trapped inside very small nanobubbles with a radius of less than 50 nanometers.

In molecules, the atoms vibrate with characteristic patterns and frequencies. Vibrations are therefore an important tool for studying molecules and molecular processes such as chemical reactions. Although scanning tunneling microscopes can be used to image individual molecules, their vibrations have so far been difficult to detect.

Physicists at Kiel University (Christian-Albrechts-Universität zu Kiel, CAU) have now invented a method with which the vibration signals can be amplified by up to a factor of 50. Furthermore, they increased the frequency resolution considerably. The new method will improve the understanding of interactions in molecular systems and further simulation methods. The research team has now published the results in the journal Physical Review Letters.

Continue reading “Physicists make molecular vibrations more detectable” »

Molecules of the rare metallic element niobium can be used as molecular building blocks to design electrochemical energy storage materials. Mark Rambaran, Department of Chemistry at Umeå University, presents in his thesis a method for producing solid materials from aqueous solutions containing nano-sized niobium molecules, called polyoxoniobates.

“These polyoxoniobates are water-soluble and can be synthesized in large volumes. They act as molecular building blocks, in the same way as when a child stacks Lego bricks,” Mark Rambaran says. “They can be used to make a wide range of materials, including supercapacitors that facilitate lithium-ion storage.”

Synthesis of polyoxoniobates can be done with microwave irradiation, because it is a rapid and efficient alternative to conventional hydrothermal methods, Mark Rambaran shows in his thesis.

There has been a lot of buzz about quantum computers and for good reason. The futuristic computers are designed to mimic what happens in nature at microscopic scales, which means they have the power to better understand the quantum realm and speed up the discovery of new materials, including pharmaceuticals, environmentally friendly chemicals, and more. However, experts say viable quantum computers are still a decade away or more. What are researchers to do in the meantime?

A new Caltech-led study in the journal Science describes how machine learning tools, run on classical computers, can be used to make predictions about quantum systems and thus help researchers solve some of the trickiest physics and chemistry problems. While this notion has been shown experimentally before, the new report is the first to mathematically prove that the method works.

“Quantum computers are ideal for many types of physics and materials science problems,” says lead author Hsin-Yuan (Robert) Huang, a graduate student working with John Preskill, the Richard P. Feynman Professor of Theoretical Physics and the Allen V. C. Davis and Lenabelle Davis Leadership Chair of the Institute for Quantum Science and Technology (IQIM). “But we aren’t quite there yet and have been surprised to learn that classical machine learning methods can be used in the meantime. Ultimately, this paper is about showing what humans can learn about the physical world.”

Strenuous cognitive work leads to an accumulation of glutamate in the prefrontal cortex, according to new research published in the journal Current Biology. The new findings suggest that mental fatigue is a neuropsychological mechanism that helps to avert the build up of potentially toxic byproducts of prolonged cognitive activity.

“Nobody knows what mental fatigue is, how it is generated and why we feel it,” said study author Antonius Wiehler, a member of the Motivation, Brain and Behavior Lab at Pitié Salpêtrière Hospital in Paris. “It has remained a mystery despite more than a century of scientific research. Machines can do cognitive tasks continuously without fatigue, the brain is different and we wanted to understand how and why. Mental fatigue has important consequences: for economic decisions, for management at work, for education at school, for clinical cure, etc.”

The researchers were particularly interested in the role of glutamate, an excitatory neurotransmitter that is involved in a variety of cognitive functions, including learning and memory. In addition, glutamate plays a role in controlling the strength of synaptic connections. Too much or too little glutamate can lead to neuronal dysfunction, so it is critical that this neurotransmitter is tightly regulated.

For Physics & Chemistry experiments for kids delivered to your door head to https://melscience.com/sBIs/ and use promo code DRBECKY50 for 50% off the first month of any subscription (valid until 22nd October 2022).

To find out whether you can see the partial solar eclipse on 25th October 2022 put in your location here: https://www.timeanddate.com/eclipse/map/2022-october-25

Continue reading “JWST observes Earendel — the most distant star known — 12.8 billion ly away | Night Sky News Sep ‘22” »

Small but mighty, lysosomes play a surprisingly important role in cells despite their diminutive size. Making up only 1–3% of the cell by volume, these small sacs are the cell’s recycling centers, home to enzymes that break down unneeded molecules into small pieces that can then be reassembled to form new ones. Lysosomal dysfunction can lead to a variety of neurodegenerative or other diseases, but without ways to better study the inner contents of lysosomes, the exact molecules involved in diseases—and therefore new drugs to target them—remain elusive.

A new method, reported in Nature on Sept. 21, allows scientists to determine all the molecules present in the lysosomes of any cell in mice. Studying the contents of these molecular recycling centers could help researchers learn how the improper degradation of cellular materials leads to certain diseases. Led by Stanford University’s Monther Abu-Remaileh, institute scholar at Sarafan ChEM-H, the study’s team also learned more about the cause for a currently untreatable neurodegenerative disease known as Batten disease, information that could lead to new therapies.

“Lysosomes are fascinating both fundamentally and clinically: they supply the rest of the cell with nutrients, but we don’t always know how and when they supply them, and they are the places where many diseases, especially those that affect the brain, start,” said Abu-Remaileh, who is an assistant professor of chemical engineering and of genetics.