Physicists discover a new method to image ultrafast electron motions in atoms

This article from the Leibniz University in Hanover seemed very interesting to me, so I presented it in full.

Physicists discover a new method to image ultrafast electron motions in atoms

An international team led by researchers from the Cluster of Excellence PhoenixD at Leibniz University Hannover (Germany) imaged the fastest and tiniest details of the electron dynamics in atoms using light with wavelengths which were until now considered far too long for this task.

“The discovery will allow novel, much easier access to the smallest temporal and spatial scales in the atomic world,” says Dr. Ihar Babushkin, Theoretical Physicist and member of the Cluster of Excellence PhoenixD at Leibniz University Hannover (LUH).

How can I measure the flight path of a butterfly when the smallest scale on my ruler is as big as the Empire State Building? This question may sound grotesque because, normally, no one would probably want to measure such a small animal with a scale many times larger. This requires a tape measure whose unit of measurement is smaller than the butterfly. Such differences in size can be found also in the smallest particles: For example, the size of atoms is measured with the unit of Ångström. One Ångström corresponds to the ten-millionth part of a millimeter (10-10 meters).

If atoms are now measured with the aid of light, the wavelength of the light serves as the unit of measurement, the “division of the ruler”. Consequently, wavelengths in the Ångström range should be the most suitable for this task. These would be X-rays, and an observer would not be expected to see much or anything at all when observing the atom in visible light with a wavelength 3000 times longer.

These ratio rules apply not only to the observation of space, but also of time: For instance, in atomic physics, one of the fastest processes is the tunnelling of an electron away from the atom when the latter is placed in a very strong electric field. Ionization takes place at attosecond time scales (10-18 second), whereas the period of a single oscillation of visible light is around one femtosecond (10-15 second).

“To study processes like this, researchers use up to now much shorter light wavelengths or the electrons escaping the atoms. Both types of measurements have significant disadvantages – they are difficult to produce and handle. But we found a solution,” says Babushkin. His research was funded by the DFG (German Research Foundation) Priority Program 1840 (QUTIF), which was initiated and is coordinated by LUH.

A group of 21 scientists headed by members of the Cluster of Excellence PhoenixD has now discovered a new way to access the smallest atomic scales. With their research, they showed that clear signatures of electron dynamics are preserved in visible light; both on the time and space scales. Moreover, much longer wavelengths — down to the millimeter (terahertz) range — can be used. This means that it is possible to scale up the dynamics at the atomic level to the size of the known macroscopic world.

The journal Nature Physics («All-optical attoclock for imaging tunnelling wavepackets») published the discovery of the researchers.

In the course of ionization in strong fields, the electron leaves the atom and is accelerated. As any accelerated charged particle, electron radiates light. Since the ionization process is very short in time, the spectrum of this radiation is very broad and includes components in ultraviolet, visible and even terahertz ranges.

The key is to look at the polarization of this emitted light. The polarization is very sensitive to the smallest details of the electron dynamics. ”Measuring light polarization allows reconstructing many aspects of electron dynamics with excellent precision,” says Babushkin.

This new type of imaging opens broad perspectives: It promises experimental setups that are tens or even hundreds of times less expensive than before and thus affordable to many more researchers worldwide.

“Besides, this allows us to observe the electron dynamics in situations when neither light at short wavelengths nor electrons are available for detection, for instance, in the bulk of solids,” says Ayhan Demircan, theoretical Physicist and member of the Cluster of Excellence PhoenixD.

Finally, optical polarization measurements can be very precise, allowing thus scientists to measure the electron dynamics as accurate as never before. “In the future,” says Babushkin, “these findings will contribute to our understanding of the light-matter interaction at the edge of possible resolution both in time and space.

Source: Leibniz University Hannover

https://www.nanowerk.com/  March 11, 2022

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Nanotechnology could benefit smart cities

Nanotechnology-enabled materials and devices will play a major role in sectors such as electronics, communications, construction, and energy; all of which are key areas for the implementation of smart cities.

This is a quote from an article by Michael Berger published on the Nanowerk website. Further materials of this article are taken from this above-mentioned article and seem to me very important.

A smart city is an infrastructure framework that addresses the growing urbanization challenges by embracing integrated and automated information and communication technologies to help optimize all city operations, help achieve sustainability goals and better quality of life for its citizens. The development of smart cities requires more efficient and less polluting transport systems, more habitable residential buildings that require less energy to operate, establishment of better

managed public services of all kinds (gas, water, electricity, waste disposal, etc.).

When it comes to nanotechnology and the development of new nanomaterials and nano devices that   smart cities can benefit from, there are several areas that immediately stand out:

Millimeter- wave technology for 5G networks for virtual city-wide networks

Nanomaterials to be used in the construction of smart buildings

Tiny sensors or even smart dust to enable city-wide IoT

Smart windows to regulate buildings' indoor climate

Efficient, smart lighting systems

Energy-generating smart roads

High storage capacity batteries and ultracapacitors with fast loading times for electric vehicles and battery storage of renewable energy.

Water purification and filtration.

Let's take a look at some of the major nanotechnologies at play:

 5G Networks                                                                                          

By providing higher data rates, increased traffic capacity, ultra-low latency, and high connection density, 5G offers opportunities for urban innovators striving to create smart city services.

In conjunction with the Internet of Things (IoT) and crowd management tools, 5G should enable transport operators to improve their response to overcrowding and deliver information to passengers on safer routes and vehicles.

Researchers have demonstrated how properties of graphene enable ultra-wide bandwidth communications coupled with low power consumption to radically change the way data is transmitted across the optical communications systems. This could make graphene-integrated devices the key ingredient in the evolution of 5G and the IoT.

Already, researchers have demonstrated wafer-scale production of graphene-based photonic devices, enabling automation and paving the way to large scale production.

There are already plans to use the sub-terahertz range as a working range in the sixth generation (6G) wireless technology, which is being prepared for active introduction in our lives from the early 2030s. Researchers have already developed magnetic nanopowders to be used in 6G reception devices.

Nanotechnology-enabled sensor technology

Data-collecting sensors embedded in all kinds of devices are at the core of IoT applications. Especially in demand are light-weight, thin, robust, and flexible sensors that can be seamlessly integrated onto any surface, which is difficult to realize in conventional electromechanical sensors.

Wireless sensors, whether electronic or photonic (light-based), can monitor such environmental factors as humidity, temperature and air pressure. One example of IoT-suitable sensing devices are fully integrated and packaged wireless sensors for environmental           monitoring applications that can be 3S printed.

Another example are graphene sensors embedded into RFIDs for wireless humidity sensing: By layering graphene oxide (a derivative of graphene) over graphene to create a flexible heterostructure the team have developed humidity sensors for remote sensing with the ability to connect to any wireless network.

Still a bit in the future is smart dust – imagine a cloud of sensors, each the size of a grain of sand or even smaller, blown aloft by hurricane winds and relaying data on the storm to weather stations below. Picture an invisible sensor network embedded into a smart city’s roads to monitor traffic, road surface damage and identify available parking spaces – all in real time. Or billions of nanosensors distributed over areas with fire hazards to detect a fire at its very beginning. Or envision programmable smart dust that triggers an alarm signal when invisible microcracks are detected in a turbine blade.

Nanomaterials to be used in building construction

Nanotechnology has a significant impact in the construction sector. Several applications have been developed for this specific sector to improve the durability and enhanced performance of construction

components, energy efficiency and safety of the buildings, facilitating the ease of maintenance and to provide increased living comfort.

Nanoparticles of TiO2, Al2O3 or ZnO are applied as a final coating on construction ceramics to bring this characteristic to the surfaces. TiO2 is being used for its ability to break down dirt or pollution when exposed to UV light and then allow it to be washed off by rainwater on surfaces like tiles, glass and sanitary ware. ZnO is used to have UV resistance in both coatings and paints. Nanosized Al2O3 particles are used to make surfaces scratch resistant. These surfaces also prevent / decelerate formation of bad smells, fungus and mould.

Basic construction materials cement, concrete and steel will also benefit from nanotechnology. Addition of nanoparticles will lead to stronger, more durable, self-healing, air purifying, fire resistant, easy to clean and quick compacting concrete. Some of the nanoparticles that could be used for these features are nano silica (silica fume), nanostructured metals, carbon nanotubes (CNTs) and carbon nanofibers (CNFs).

A bit more futuristic: With the addition of engineered nanomaterials that change the crystalline structure of concrete, imaginative architectural designs become  possible and buildings achieve new heights and forms. Steel reinforcements are a thing of the past as concrete structures have ample strength to support themselves, in shapes that make the Guggenheim Museum look tame. Engineered from the strongest, lightest nanomaterials, suspension bridges and other weight-bearing elements look more like spider webs than structures.

Already, researchers have demonstrated strengthening of concrete by infusing it with nanocrystals or by nanoengineering concrete with graphene, resulting in a new composite material that is more than

twice as strong and four times more water resistant than existing concretes.

Widespread use of engineered nanomaterials in the Smart City

Engineered nanomaterials are expected to be widely used in city environments. Carbon dioxide and other air pollutants are reduced as power plants, buildings, and vehicles use nanostructured membranes. Recycled water is purified with nano-enabled filtration and osmosis systems, for instance by using nanofiltration membranes to treat industrial wastewater from heavy metals, and these systems are available for individual households and new local urban water treatment systems.

Nanowerk, 2021

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3D nano-inks push industry boundaries

Nanocomposite ink using carbon nanotubes certainly pushes the boundaries of the industry. In this regard, the materials presented in this work are of great interest. I will cite the most interesting points from an article presented by  Michigan  Technological University.

Mechanical engineering researchers at Michigan Technological University have created a way to make nanocomposite polymer inks for 3D printing that use carbon nanotubes (CNTs), known for their high tensile strength and lightness. This revolutionary ink can replace epoxies, and understanding why their properties are so fantastic is the first step to mainstream use.

3D printing, also known as additive manufacturing, is more versatile and efficient than casting. It adds material with high precision, often complex geometries, with significantly less excess material that needs to be cut off. The addition of low-dimensional nanomaterials such as CNTs, graphene, metal nanoparticles, and quantum dots allows printed materials on a 3D printer to adapt to external influences, giving them properties such as electrical and thermal conductivity, magnetism, and electrochemical storage.

The exploration of the process, morphology, and properties of polymeric inks is the subject of an article recently published in the journal Additive Manufacturing by Parisa Pour Shahid Saeed Abadi, an engineer who explores the interface of materials, mechanics, and medicine, and graduate student Masoud Kasraie («Additive manufacturing of conductive and high-strength epoxy-nano clay-carbon nanotube composites»).

Abadi and Kasraie point out that before researchers can sprint off to the races using polymeric inks, they must first learn to walk. The first step is digging into the intersection of the macro scale (how our eyes see a material performing) and the nanoscale (what we can’t see, but know is occurring).

Abadi noted, that While polymer nanocomposites and 3D-printing products and services both have billion-dollar market values, nanomaterial 3D printing only has a market value of approximately $43 million.

For national prosperity and sustaining global leadership in manufacturing, the gap between the real-world applications of 3D printing and nanomaterials versus nanomaterial 3D printing needs to be closed,” Abadi said. “The gap exists due to lack of control of nanocomposite properties in the 3D-printing process  because we don’t fully understand the process-morphology-property relationship.”

The authors note many benefits of nanomaterial ink. They say that Moving beyond the science of nanocomposite ink, the material holds great promise because of its many functionalities. One advantage of 3D printing is near-complete control over the final product’s shape.

Source:  Michigan Technological University

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World’s first fibre optic ultrasonic imaging probe for future nanoscale disease diagnostics

Scientists at the University of Nottingham have developed an ultrasonic imaging system, which can be deployed on the tip of a hair-thin optical fibre, and will be insertable into the human body to visualise cell abnormalities in 3D.

The new technology produces microscopic and nanoscopic resolution images that will one day help clinicians to examine cells inhabiting hard-to-reach parts of the body, such as the gastrointestinal tract, and offer more effective diagnoses for diseases ranging from gastric cancer to bacterial meningitis.

The high level of performance the technology delivers is currently only possible in state-of-the-art research labs with large, scientific instruments — whereas this compact system has the potential to bring it into clinical settings to improve patient care.

The Engineering and Physical Sciences Research Council (EPSRC) -funded innovation also reduces the need for conventional fluorescent labels — chemicals used to examine cell biology under a microscope — which can be harmful to human cells in large doses.

The findings are being reported in a new paper, entitled ‘Phonon imaging in 3D with a fibre probe’ published in the journal, Light: Science & Applications ("Phonon imaging in 3D with a fibre probe”)

Paper author, Salvatore La Cavera, an EPSRC Doctoral Prize Fellow from the University of Nottingham Optics and Photonics Research Group, said of the ultrasonic imaging system: “We believe its ability to measure the stiffness of a specimen, its bio-compatibility, and its endoscopic-potential, all while accessing the nanoscale, are what set it apart. These features set the technology up for future measurements inside the body; towards the ultimate goal of minimally invasive point-of-care diagnostics.”

Currently, at the prototype stage, the non-invasive imaging tool, described by the researchers as a “phonon probe”, is capable of being inserted into a standard optical endoscope, which is a thin tube with a powerful light and camera at the end that is navigated into the body to find,  analyse,  and operate on cancerous lesions, among many other diseases. Combining optical and phonon technologies could be advantageous; speeding up the clinical workflow process and reducing the number of invasive test procedures for patients.

3D mapping capabilities

Just as a physician might conduct a physical examination to feel for abnormal ‘stiffness’ in tissue under the skin that could indicate tumours, the phonon probe will take this ‘3D mapping’ concept to a cellular level.

By scanning the ultrasonic probe in space, it can reproduce a three-dimensional map of stiffness and spatial features of microscopic structures at, and below, the surface of a specimen (e.g. tissue); it does this with the power to image small objects like a large-scale microscope, and the contrast to differentiate objects like an ultrasonic probe.

“Techniques capable of measuring if a tumour cell is stiff have been realised with laboratory microscopes, but these powerful tools are cumbersome, immobile, and unadaptable to patient-facing clinical settings. Nanoscale ultrasonic technology in an endoscopic capacity is poised to make that leap,” adds Salvatore La Cavera.

The optical fibre imaging sensor has a diameter of 125 micrometres approximately the size a human hair. Читать запись полность. »

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Researchers found potential new nanoparticles to treat brain cancer

Researchers reported a comprehensive investigation of a promising type of nanoparticle that could potentially be used for intractable brain cancers in combined therapy. The study, which was led by Dr Moeava Tehei and researchers from the University of Wollongong in combination with clinical partners, characterised and evaluated the properties of nanoparticles made from lanthanum manganite, that were doped with silver atoms. The investigators found that the nanoparticles had a potential clinical application for their synergistic effects to be used in combination with radiation treatment, hyperthermia (using heat to kill cancer cells) and their intrinsic toxicity to cancer cells. The research was published in Materials Science & Engineering C («First extensive study of silver-doped lanthanum manganite nanoparticles for inducing selective chemotherapy and radio-toxicity enhancement»). Nanoparticles are small enough to cross the blood-brain barrier that prohibits other therapies. In addition to a wide variety of other methods of analysis, studies of the magnetic properties were undertaken at ANSTO. The magnetic properties were important because they could be used to get the nanoparticles to the target cancer site and in magnetic hyperthermia treatment. Dr Kirrily Rule, a co-author on the paper, supervised investigations of magnetic and chemical changes to nanoparticles of silver-doped lanthanum manganite at two temperatures on the high-resolution powder diffractometer Echidna at ANSTO’s Australian Centre for Neutron Scattering. Although an expert in the magnetic behaviour of low-dimensional materials with quantum properties, Rule said she was excited by the opportunity to change focus and assist in medical physics-related research. The magnetic behaviour of the nanoparticles at two temperatures was important to the study because the magnetic properties of the silver-doped nanoparticles change at different transition temperatures. The magnetism measurements on Echidna were performed at 10 degrees Kelvin and 300 Kelvin. At about 300 degrees Kelvin, close to body temperature, the magnetic ordering stops. “There is a critical temperature region for hyperthermia treatment,” said Rule. The magnetisation results indicated that the nanomaterial was more likely to order ferromagnetically and that the ordering temperature when the magnetic moments aligned, was higher for a higher percentage of silver. “So, it appears that the silver was responsible for the higher transition temperatures of these nanoparticles,” said Rule. The most promising sample for hyperthermia and cancer toxicity was lanthanum manganite that was doped with a 10 per cent concentration of silver, as it retained a level of ferromagnetism at 300 degrees Kelvin. However, Dr Tehei said that the 5 per cent doping may turn out to be the most interesting when combined with radiation because of its selectivity and cancer toxicity. This suggested to the investigators that the temperature range for hyperthermia treatments could be manipulated by modifying the doping percentage. Importantly, the biological effects of the nanoparticles and doped nanoparticles were toxic to cancer cells but not the normal cells. The research helped elucidate how the doped nanoparticles were killing cancer cells by producing high levels of reactive oxidative stress. Source: ANSTO,  Nanowerk News,  Apr. 16, 2021

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Building mRNA vaccines for COVID19

Building mRNA vaccines for COVID-19
Coronaviruses invade cells through surface molecules called spike proteins (named for the fact that they physically jut out from the rest of the virus), which take on different shapes in different coronaviruses. The SARS-CoV-2 specific spike protein is therefore a crucial antigen – i.e. a substance that induces the immune system to produce antibodies against it – that can be exploited for vaccine design.
And this is how an mRNA vaccine against COVID-19 works: Once the virus genome is sequenced – that means it is available as a digital copy – researchers can design an mRNA sequence that encodes the blueprint for the virus spike protein. Once tested for efficacy and safety in clinical trials, the mRNA molecule can then be synthesized on an industrial scale in robotic factories.
This mRNA molecule is wrapped with a lipid nanoparticle envelope, which protects it from degradation, and then directly delivered into cells. There, ribosomes get to work and read the mRNA as just any other blueprint – only this time they synthesize the spike protein. The finished spike proteins are then attached to the surface of cells where they are recognized by the immune system, eventually triggering the desired immune response against the virus.In other words: Once you get your vaccine jab, the genetic instructions contained in the mRNA molecules are injected into the upper arm and the ribosomes in the muscle cells translate them to make a critical fragment of the viral protein directly inside your body. This 'preview' of what the real virus looks like gives the immune system time to design powerful antibodies that can neutralize the real virus if it ever gets in contact with it.The protein production inside the muscle cells initiated by the injected mRNA injection reaches peak levels for 24 to 48 hours and can last for a few more days. Thereafter, the mRNA molecules get disassembled by the body.

The revolutionary impact of mRNA technology

mRNA COVID-19 vaccines have demonstrated in a very convincing way that biotechnologies have entered the industrial age. What we are seeing here is nothing less than the rise of bio platforms that give us the ability to engineer bits of biology, such as mRNA, to create programmable medicines and vaccines.

More generally, if it is indeed possible that mRNA can be used to make the full set of proteins in life, then it becomes possible to treat an incredible broad range of human diseases. This is at the core of the industrialized platforms that Moderna, BioNTech and others are building.

Essentially, an mRNA technology platform functions very much like an operating system on a computer. It is designed so that it can plug and play interchangeably with different programs. In this case, the 'program' or 'app' is the unique mRNA sequence that codes for a specific protein.

mRNA as the technological basis for therapeutics and vaccines is characterized by a great flexibility with respect to production and application. In essence, mRNA is an information-carrying molecule that can be industrialized – as opposed to traditional therapeutic molecules that have to be elaborately designed and synthesized from scratch for each application (i.e. medicine).

For starters, mRNA molecules are far simpler than proteins. mRNA is manufactured by chemical rather than biological synthesis, so it is much quicker than conventional vaccines to be redesigned, scaled up and mass-produced.

An excellent primer on the development of mRNA-vaccine technologies explains why: «Any protein can be encoded and expressed by mRNA, in principle enabling the development of prophylactic and therapeutic vaccines fighting diseases as diverse as infections and cancer as well as protein replacement therapies.»

And this is very the disruptive effect of the mRNA platform happens: If a therapy requires a certain protein to be encoded, only the sequence of the messenger RNA molecule needs to be changed, leaving its physicochemical characteristics largely unaffected. In the above computer analogy, that is like writing a new piece of software that runs on the same operating system.

The disruptive force of emerging bio platforms

This means that diverse products can be manufactured using the same established production

process – the same equipment, the same operators – without any adjustment and thereby saving massive amounts of time and money compared with other vaccine or therapeutics platforms. Читать запись полность. »

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Role of nanotechnology in the race to find a Covid-19 vaccine

Today I would like to acquaint readers of my blog with a summary of the data published on the site Nanowerk about the role of nanotechnology in the race for the Covid-19 vaccine.

Nicole Steinmetz, professor of nanoengineering at UC San Diego and corresponding author on the study, spoke with Nanowerk about the findings in this paper. Steinmetz believes “it is an exciting time for nanotechnology and nanoparticle delivery of nucleic acid-based vaccines and subunit vaccines are poised to make an impact.”

The COVID-19 pandemic has left the world reeling following its inception in Wuhan, China. While global efforts are being directed towards a vaccine, thus far none have passed the trial stage. Until humanity achieves herd immunity to this virus, either through exposure and infection or through inoculation, there can be little hope of our returning to our pre-COVID-19 life.

Fortunately, there are over two hundred academic laboratories and companies around the world searching for a vaccine, and the pace at which they are progressing is unprecedented. One nanotechnology formulation achieved clinical trials a month prior to other conventional approaches. However, due to the stiff regulatory requirements on vaccines to ensure safety, there remain various hurdles that companies must surmount in order to establish a viable vaccine.

Nanotechnological approaches have received a boost despite their lack of clinical trials. As an example, mRNA vaccines have been developing for thirty years but were not previously approved. Due to the adaptability of such technology, prior vaccine candidates can be repurposed using previously developed nanostructures.

Nanoparticles and viruses operate on the same scale, and thus there are various nanotechnological aides which are being used in the development of potential vaccines. Nanoparticles are capable of entering the cell through biological channels, and can deliver antigens there. Antigens are typically delivered via either lipid nanoparticles (LNPs), which encapsulate the antigens, or via other benign viruses including Ads.

Due to the scale of nanoparticles, they are capable of traveling in vivo differently than other molecules. The lymphatic system, which is critical in orchestrating immune responses, has typically proved challenging to access. However, with the advent of nanoparticles, previously inaccessible pathways have become accessible, with certain trial vaccines attempting to use these to transport antigens.

Besides delivering antigens themselves, nanoparticles can also be enlisted to provide adjuvants to cells. Adjuvants effectively catalyze the immune response, allowing the cell to more easily recognize and respond to antigens. Encapsulating both the antigen and adjuvant in the same envelope provides for better-targeted delivery and response from the cell.

The presence of adjuvants may also reduce the amount of antigen required to engender a response, and thus render a dose-sparing effect. This dose-sparing may drive the cost of immunization down, and render wide-spread inoculations more feasible. Without co-delivery of adjuvants and antigens, antigens are more likely to break down in the body. Читать запись полность. »

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