University of Maryland Engineers Open Door to Big New Library of Tiny Nanoparticles


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The development of bimetallic nanoparticles (i.e., tiny particles composed of two different metals that exhibit several new and improved properties) represents a novel area of research with a wide range of potential applications.

Now, a research team in the University of Maryland (UMD)’s Department of Materials Science and Engineering (MSE) has developed a new method for mixing metals generally known to be immiscible, or unmixable, at the nanoscale to create a new range of bimetallic materials.

Such a library will be useful for studying the role of these bimetallic particles in various reaction scenarios such as the transformation of carbon dioxide to fuel and chemicals.

The study, led by MSE Professor Liangbing Hu, was published in Science Advances on April 24, 2020. Chunpeng Yang, an MSE Research Associate, served as first author on the study.

“With this method, we can quickly develop different bimetallics using various elements, but with the same structure and morphology,” said Hu. “Then we can use them to screen catalytic materials for a reaction; such materials will not be limited by synthesizing difficulties.”

The complex nature of nanostructured bimetallic particles makes mixing such particles difficult, for a variety of reasons—including the chemical makeup of the metals, particle size, and how metals arrange themselves at the nanoscale—using conventional methods.

This new non-equilibrium synthesismethod exposes copper-based mixes to a thermal shock of approximately 1300 ̊ Celsius for .02 seconds and then rapidly cools them to room temperature. The goal of using such a short interval of thermal heat is to quickly trap, or ‘freeze,’ the high-temperature metal atoms at room temperature while maintaining their mixing state.

In doing so, the research team was able to prepare a collection of homogeneous copper-based alloys. Typically, copper only mixes with a few other metals, such as zinc and palladium—but by using this new method, the team broadened the miscible range to include copper with nickel, iron, and silver, as well.

“Using a scanning electron microscope (SEM) and transmission electron microscope (TEM), we were able to confirm the morphology – how the materials formed – and size of the resulting Cu-Ag [copper-silver] bimetallic nanoparticles,” Yang said.

This method will enable scientists to create more diverse nanoparticle systems, structures, and materials having applications in catalysis, biological applications, optical applications, and magnetic materials.

As a model system for rapid catalyst development, the team investigated copper-based alloys as catalysts for carbon monoxide reduction reactions, in collaboration with Feng Jiao, a professor in the Department of Chemical and Biomolecular Engineering at the University of Delaware.

The electro-catalysis of carbon monoxide reduction (COR) is an attractive platform, allowing scientists to use greenhouse gas and renewable electrical energy to produce fuels and chemicals.

“Copper is, thus far, the most promising monometallic electrocatalyst that drives carbon monoxide reduction to value-added chemicals,” said Jiao. “The ability to rapidly synthesize a wide variety of copper-based bimetallic nanoalloys with a uniform structure enables us to conduct fundamental studies on the structure-property relationship in COR and other catalyst systems.”

This non-equilibrium synthetic strategy can be extended to other bimetallic or metal oxide systems, too. Utilizing artificial intelligence-based machine learning, the method will make rapid catalyst screening and rational design possible.

For additional information:

Yang, C., et al. (24 April 2020). Overcoming Immiscibility Toward Bimetallic Catalyst Library, Science Advances. DOI: 10.1126/sciadv.aaz6844

Tiny Nanoparticles Offer Large Potential for Brain Cancer Treatment


tiny brain nanoparticles 1-tinynanopartFor patients with malignant brain tumors, the prognosis remains dismal. With the most aggressive treatments available, patients are usually only expected to live about 14 months after a diagnosis

This is because, chemotherapy, the most common form of treatment for cancer, is uniquely challenging for   patients. The delicate organ in our skulls is protected by a network of vessels and tissue called the blood-brain barrier that keeps most foreign substances out. Furthermore,  can cause significant damage to the rest of the body if they are not able to target the tumor in a pharmacologically significant dose.

These challenges have plagued scientists for years, but a team of researchers for Yale School of Medicine and Beijing Normal University just published a breakthrough study detailing a new method that offers a promise at treatment. The solution? Nanoparticles.

Nanoparticles, particles that are smaller than wavelengths of visible light and can only be seen under a special microscope, have the potential to pass through the blood-brain barrier. They can also carry drugs to targeted areas of the body, reducing the side effects on the rest of the body. But previous nanoparticles were very complex and not very efficient in penetrating in the brain.

This most recent paper, published in Nature Biomedical Engineering on March 30, 2020, describes a small carbon nanoparticle engineered by the two labs that could both deliver chemotherapy drugs across the blood-brain barrier and mark tumor cells with fluorescence in mice. What’s more, this nanoparticle is incredibly simple—made up of only one single compound.

“The major problems we’ve solved is to improve the delivery efficiency and specificity of nanoparticles,” says Jiangbing Zhou, Ph.D., associate Professor of Neurosurgery and of Biomedical Engineering at Yale School of Medicine. “We created nanoparticles like building a missile. There’s usually a GPS on every missile to guide it into a specific location and we’re able to guide particles to penetrate the brain and find tumors.”

The GPS-like targeting occurs because the nanoparticles engineered to be recognized by a molecule called LAT1, which is present in the blood-brain  as well as many tumors, but not in most other normal organs. As a result, chemotherapy drugs can be loaded on the dots and target tumors while barely affecting the rest of the body. The nanoparticles gain entry to the brain because they’ve been engineered to look like amino acids, which are allowed past the  as nutrients.

The nanoparticles have wider implications than  delivery. They can be stimulated to emit a fluorescence, which helps surgeons locate tumor to remove with greater accuracy.

Still, there’s a long road ahead before this research can be applied in a clinical setting, says Dr. Zhou. “It takes a long time before the technology can be translated into clinical applications,” he says. “But this finding suggests a new direction for developing  for drug delivery to the brain by targeting LAT1 molecules.”


Explore further

Improving drug delivery for brain tumor treatment


More information: Shuhua Li et al. Targeted tumour theranostics in mice via carbon quantum dots structurally mimicking large amino acids, Nature Biomedical Engineering (2020). DOI: 10.1038/s41551-020-0540-y

Journal information: Nature Biomedical Engineering

MIT: Researchers Achieve Remote control of Hormone Release Using Magnetic Nanoparticles


Magnetic Nanoparticles 13-researchersa
MIT engineers have developed magnetic nanoparticles (shown in white squares) that can stimulate the adrenal gland to produce stress hormones such as adrenaline and cortisol. Credit: Massachusetts Institute of Technology

Abnormal levels of stress hormones such as adrenaline and cortisol are linked to a variety of mental health disorders, including depression and posttraumatic stress disorder (PTSD). MIT researchers have now devised a way to remotely control the release of these hormones from the adrenal gland, using magnetic nanoparticles.

This approach could help scientists to learn more about how  release influences mental health, and could eventually offer a new way to treat hormone-linked disorders, the researchers say.

“We’re looking how can we study and eventually treat stress disorders by modulating peripheral organ function, rather than doing something highly invasive in the central nervous system,” says Polina Anikeeva, an MIT professor of materials science and engineering and of brain and cognitive sciences.

To achieve control over hormone release, Dekel Rosenfeld, an MIT-Technion postdoc in Anikeeva’s group, has developed specialized  that can be injected into the adrenal gland. When exposed to a weak magnetic field, the particles heat up slightly, activating heat-responsive channels that trigger hormone release. This technique can be used to stimulate an organ deep in the body with minimal invasiveness.

Anikeeva and Alik Widge, an assistant professor of psychiatry at the University of Minnesota and a former research fellow at MIT’s Picower Institute for Learning and Memory, are the senior authors of the study. Rosenfeld is the lead author of the paper, which appears today in Science Advances.

Controlling hormones

Anikeeva’s lab has previously devised several novel magnetic nanomaterials, including particles that can release drugs at precise times in specific locations in the body.

In the new study, the research team wanted to explore the idea of treating disorders of the brain by manipulating organs that are outside the central nervous system but influence it through hormone release. One well-known example is the hypothalamic-pituitary-adrenal (HPA) axis, which regulates stress response in mammals. Hormones secreted by the , including cortisol and adrenaline, play important roles in depression, stress, and anxiety.

“Some disorders that we consider neurological may be treatable from the periphery, if we can learn to modulate those local circuits rather than going back to the global circuits in the ,” says Anikeeva, who is a member of MIT’s Research Laboratory of Electronics and McGovern Institute for Brain Research.

As a target to stimulate hormone release, the researchers decided on  that control the flow of calcium into adrenal cells. Those ion channels can be activated by a variety of stimuli, including heat. When calcium flows through the open channels into adrenal cells, the cells begin pumping out hormones. “If we want to modulate the release of those hormones, we need to be able to essentially modulate the influx of calcium into adrenal cells,” Rosenfeld says.

Unlike previous research in Anikeeva’s group, in this study magnetothermal stimulation was applied to modulate the function of cells without artificially introducing any genes.

To stimulate these heat-sensitive channels, which naturally occur in adrenal cells, the researchers designed nanoparticles made of magnetite, a type of iron oxide that forms tiny magnetic crystals about 1/5000 the thickness of a human hair. In rats, they found these particles could be injected directly into the adrenal glands and remain there for at least six months. When the rats were exposed to a weak magnetic field—about 50 millitesla, 100 times weaker than the fields used for magnetic resonance imaging (MRI)—the particles heated up by about 6 degrees Celsius, enough to trigger the calcium channels to open without damaging any surrounding tissue.

The heat-sensitive  that they targeted, known as TRPV1, is found in many sensory neurons throughout the body, including . TRPV1 channels can be activated by capsaicin, the organic compound that gives chili peppers their heat, as well as by temperature. They are found across mammalian species, and belong to a family of many other channels that are also sensitive to heat.

This stimulation triggered a hormone rush—doubling cortisol production and boosting noradrenaline by about 25 percent. That led to a measurable increase in the animals’ heart rates.

Treating stress and pain

The researchers now plan to use this approach to study how hormone release affects PTSD and other disorders, and they say that eventually it could be adapted for treating such disorders. This method would offer a much less invasive alternative to potential treatments that involve implanting a medical device to electrically stimulate hormone release, which is not feasible in organs such as the adrenal glands that are soft and highly vascularized, the researchers say.

Another area where this strategy could hold promise is in the treatment of pain, because heat-sensitive ion channels are often found in pain receptors.

“Being able to modulate pain receptors with this technique potentially will allow us to study pain, control pain, and have some clinical applications in the future, which hopefully may offer an alternative to medications or implants for chronic pain,” Anikeeva says. With further investigation of the existence of TRPV1 in other organs, the technique can potentially be extended to other peripheral organs such as the digestive system and the pancreas.


Explore further

The myth behind adrenal fatigue


More information: Dekel Rosenfeld et al. Transgene-free remote magnetothermal regulation of adrenal hormones, Science Advances (2020). DOI: 10.1126/sciadv.aaz3734

Journal information: Science Advances

Active Ingredients-Coated Nanoparticles Could Destroy Cancer Cells


Coated Nano Particles 1 image3D architecture of the cell with different organelles: mitochondria (green), lysosomes (purple), multivesicular bodies (red), endoplasmic reticulum (cream). Image Credit: © Burcu Kepsutlu/HZB.

Nanoparticles have the ability to make their way easily into cells. For the first time, high-resolution 3D microscopy images from BESSY II offer new insights about their distribution and function.

Nanoparticles easily penetrate cells. How they are distributed there and what they do is shown for the first time by high-resolution 3D microscopy images on BESSY II. For example, certain nanoparticles accumulate preferentially in certain organelles of the cell. This can increase the energy turnover in the cell. “The cell looks like a marathon, obviously it takes energy to absorb such nanoparticles,” says lead author James McNally.

Today, nanoparticles are not only in cosmetic products, but everywhere, in the air, in water, in the soil and in food. Because they are so tiny, they easily penetrate cells in our body. This is also of interest for medical applications: Nanoparticles coated with active ingredients could be specifically introduced into cells, for example to destroy cancer cells. However, a lot has hardly been researched: for example, how nanoparticles are distributed in the cells, what they do there and how this effect depends on their size and coating.

Overview of the entire cell

A study at BESSY II has now brought new insights, where Prof. Gerd Schneider’s team can carry out X-ray microscopy images with soft, intensive X-rays. A group around the HZB biophysicist Dr. James McNally has used X-ray microscopy to examine cells with differently coated nanoparticles. The nanoparticles were exactly the same size, but coated with different active ingredients. “X-ray microscopy offers significantly better resolutions than light microscopy and a much better overview than electron microscopy,” emphasizes Schneider.

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The cell looks like it has just run a marathon, apparently, the cell requires energy to absorb such nanoparticles. – Dr James McNally, Study Lead Author and Biophysicist, Helmholtz-Zentrum Berlin

 

Energy storage is decreasing

“X-ray microscopy allows us to see the cell as a whole, so we were able to observe this peculiarity for the first time,” explains McNally. “We found that the uptake of nanoparticles increases the number of mitochondria and endosomes, while other organelles, namely lipid droplets and multivesicular bodies, decrease,” says Burcu Kepsutlu, who carried out the experiments for her doctorate.

 When we go on a starvation diet or run a marathon, we see similar changes in the cell – namely an increase in mitochondria and a decrease in lipid droplets,” says McNally. “Apparently it takes energy for the cell to absorb the nanoparticles, and it feels like after a marathon.”

Accumulation in organelles

For the first time, they received complete, three-dimensional, high-resolution images of the cells with the organelles contained therein, including lipid droplets, multivesicular bodies, mitochondria and endosomes. Lipid droplets act as energy stores in the cell, while mitochondria metabolize this energy. 

The analysis of the images showed: The nanoparticles accumulate preferentially in cell organelles and then change the number of certain organelles in favor of other organelles. These changes were almost independent of the respective coating of the nanoparticles. This suggests that different coatings could have similar effects.  Further studies with other types of nanoparticles and in particular other cell types must show whether this effect can be generalized.

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3D Image of the Cell and its Organelles

X-ray microscopy offers significantly better resolution than light microscopy, and a much better overview than electron microscopy. – Gerd Schneider, Professor, Helmholtz-Zentrum Berlin

The researchers acquired, for the first time, comprehensive, 3D, high-resolution images of the cells treated with the nanoparticles, where the organelles—including mitochondria, lipid droplets, endosomes, and multivesicular bodies—were contained within. Lipid droplets act as energy stores in the cell, while mitochondria metabolize this energy.

Accumulation of Nanoparticles

Investigation of the images revealed that the nanoparticles tend to build up preferentially within a subset of the cell organelles. Moreover, the nanoparticles alter the number of particular organelles at the cost of other organelles.

The variations in the numbers of organelles were identical irrespective of the nanoparticle coating. This shows that various different types of nanoparticle coatings may produce a similar effect. Further research with other cell types and with other nanoparticle coatings is necessary to assess how general this effect is.

Number of Lipid Droplets Decreases

X-ray microscopy allows us to see the cell as a whole, so we were able to observe this behavior for the first time,” McNally explained.

We found that the absorption of such nanoparticles increases the number of mitochondria and endosomes, while other organelles, namely lipid droplets and multivesicular bodies, decrease. – Burcu Kepsutlu, Researcher, Helmholtz-Zentrum Berlin

Kepsutlu performed the experiments for her doctorate.

 

ACS Nano (2020): Cells Subject Major Changes in the Quantity of Cytoplasmic Organelles after Uptake of Gold Nanoparticles with Biologically Relevant Surface Coatings, Burcu Kepsutlu, Virginia Wycisk, Katharina Achazi, Sergey Kapishnikov, Ana Joaquina Pérez-Berná, Peter Guttmann, Antje Cossmer , Eva Pereiro, Helge Ewers, Matthias Ballauff, Gerd Schneider, James G. McNally

DOI: 10.1021 / acsnano.9b09264

 

 

New Approach to Treating Lung Cancer with Inhaled Nanoparticles – Wake Forest University


Deep Breath download

A new technique for treating lung cancer by inhaling nanoparticles created at Wake Forest School of Medicine, part of Wake Forest Baptist Health, has been reported by researchers.

As part of the proof-of-concept study, Dawen Zhao, MD, PhD, associate professor of biomedical engineering at Wake Forest School of Medicine, made use of a mouse model to ascertain whether metastatic lung tumors responded to an inhalable nanoparticle-immunotherapy system in combination with the radiation therapy that is usually used for the treatment of lung cancer.

The study has been reported in the current issue of Nature Communications.

The second most common type of cancer is lung cancer, which is also the leading cause of cancer-related deaths among both men and women. More people die due to lung cancer compared to breast, colon, and prostate cancers combined. Immunotherapy looks promising, but at present, it works in less than 20% of patients suffering from lung cancer.

Considerable clinical evidence indicates that during diagnosis, the tumors of a majority of the patients are poorly infiltrated by immune cells. Such a “cold” immune environment in tumors inhibits the immune system of the body from identifying and destroying the tumor cells.

WATCH: “A Deep Breath Makes the Medicine Go Down”

QUT pharmaceutical scientist Dr. Nazrul Islam, from School of Clinical Sciences, said lung cancer was one of the most common cancers globally and one of the deadliest, being a leading cause of cancer deaths. Credit: Queensland University of Technology

 

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According to Zhao, the ability to overcome such an immunosuppressive tumor environment to work efficiently against the cancer is now an area of keen interest among the scientific community.

Earlier techniques include directly injecting immunomodulators into tumors to improve their immune response. But this technique is usually restricted to surface and tumors that can be easily accessed. Thus, it can be less effective if repeated injections are required to preserve immune response.

The goal of our research was to develop a novel means to convert cold tumors to hot, immune-responsive tumors. We wanted it to be non-invasive without needle injection, able to access multiple lung tumors at a time, and be safe for repeated use. We were hoping that this new approach would boost the body’s immune system to more effectively fight lung cancer.

Dawen Zhao, Associate Professor of Biomedical Engineering, Wake Forest School of Medicine

The nanoparticle-immunotherapy system developed by Zhao and his colleagues administered immunostimulants through inhalation to a mouse model of metastatic lung cancer. When the immunostimulant-loaded nanoparticle was deposited in the air sacs of the lungs, they were absorbed by one particular type of immune cells, known as antigen-presenting cells (APC).

Then cGAMP, an immunostimulant in the nanoparticle, was discharged within the cell, where the APC cell was activated by the stimulation of a specific immune pathway (STING). This is a crucial step in inducing systemic immune response.

The researchers also demonstrated that when the nanoparticle inhalation was combined with radiation applied onto a part of one lung, the result was the regression of tumors in both lungs and prolonged survival of the mice. Moreover, the researchers noted that it thoroughly removed lung tumors in a few of the mice.

The researchers then performed mechanistic studies and showed that the inhalation system transformed the initially cold tumors in both lungs to hot tumors desirable for powerful anti-cancer immunity.

The inhalable immunotherapy developed by Zhao offers various key benefits to earlier techniques—specifically the capability to access deep-rooted lung tumors, since the aerosol that carries the nanoparticulate was designed such that it reaches all portions of the lung—and the viability of repeated treatment by employing a non-irritating aerosol formulation.

It was demonstrated that the treatment was well-tolerated and safe without any adverse immune-related distress in the mice.

The Wake Forest School of Medicine scientists have filed a provisional patent application for their inhalable nanoparticle-immunotherapy system.

Source: https://www.wakehealth.edu/

 

 

 

 

 

 

 

Converting CO2 to Valuable Resources (ethanol and propanol) with the help of Nanoparticles


Ruhr CO2 1 2019_09_27_schuhmann_jacs_tk_01

An international research team has used nanoparticles to convert carbon dioxide into valuable raw materials. The team transferred this mechanism to metallic nanoparticles, also known as nanozymes. The chemists used carbon dioxide to produce ethanol and propanol, which are common raw materials for the chemical industry.

An international research team has used nanoparticles to convert carbon dioxide into valuable raw materials. Scientists at Ruhr-Universität Bochum in Germany and the University of New South Wales in Australia have adopted the principle from enzymes that produce complex molecules in multi-step reactions. The team transferred this mechanism to metallic nanoparticles, also known as nanozymes. The chemists used carbon dioxide to produce ethanol and propanol, which are common raw materials for the chemical industry.

The team led by Professor Wolfgang Schuhmann from the Center for Electrochemistry in Bochum and Professor Corina Andronescu from the University of Duisburg-Essen, together with the Australian team led by Professor Justin Gooding and Professor Richard Tilley, reported in the Journal of the American Chemical Society on 25 August 2019.

“Transferring the cascade reactions of the enzymes to catalytically active nanoparticles could be a decisive step in the design of catalysts,” says Wolfgang Schuhmann.

Ruhr U CO2 2 nanoparticles

Credit: CC0 Public Domain

Particle with two active centres

Enzymes have different active centres for cascade reactions, which are specialised in certain reaction steps. For example, a single enzyme can produce a complex product from a relatively simple starting material. In order to imitate this concept, the researchers synthesised a particle with a silver core surrounded by a porous layer of copper. The silver core serves as the first active centre, the copper layer as the second. Intermediate products formed at the silver core then react in the copper layer to form more complex molecules, which ultimately leave the particle.

In the present work, the German-Australian team showed that the electrochemical reduction of carbon dioxide can take place with the help of the nanozymes. Several reaction steps on the silver core and copper shell transform the starting material into ethanol or propanol.

“There are also other nanoparticles that can produce these products from CO2 without the cascade principle,” says Wolfgang Schuhmann. “However, they require considerably more energy.”

The researchers now want to further develop the concept of the cascade reaction in nanoparticles in order to be able to selectively produce even more valuable products such as ethylene or butanol.

Story Source:

Materials provided by Ruhr-University BochumNote: Content may be edited for style and length.


Journal Reference:

  1. Peter B. O’Mara, Patrick Wilde, Tania M. Benedetti, Corina Andronescu, Soshan Cheong, J. Justin Gooding, Richard D. Tilley, Wolfgang Schuhmann. Cascade Reactions in Nanozymes: Spatially Separated Active Sites inside Ag-Core–Porous-Cu-Shell Nanoparticles for Multistep Carbon Dioxide Reduction to Higher Organic MoleculesJournal of the American Chemical Society, 2019; 141 (36): 14093 DOI: 10.1021/jacs.9b07310

Magnetic Nanoparticles ease Removal of ‘microcontaminants’ from Wastewater


efficientremMany wastewater treatment plants do not completely remove chemical substances from wastewater. Credit: Symbol image: Shutterstock

Microcontaminants place a considerable burden on our water courses, but removing them from wastewater requires considerable technical resources. Now, ETH researchers have developed an approach that allows the efficient removal of these problematic substances.

In our , we all use a multitude of chemical substances, including cosmetics, medications, contraceptive pills, plant fertilisers and detergents—all of which help to make our lives easier. However, the use of such products has an adverse effect on the environment, because many of them cannot be fully removed from wastewater at today’s treatment plants. As , they ultimately end up in the environment, where they place a burden on fauna and flora in our water courses.

As part of a revision of the Waters Protection Act, parliament therefore decided in 2014 to fit an additional purification stage to selected water treatment plants by 2040 with a view to removing microcontaminants. Although the funding for this has in principle been secured, the project presents a challenge for plant operators because it is only possible to remove the critical substances using complex procedures, which are typically based on ozone, activated carbon or light.

Nanoparticles aid degradation

Now, researchers at ETH Zurich’s Institute of Robotics and Intelligent Systems have developed an elegant approach that could allow these substances to be removed more easily. Using multiferroic , they have succeeded in inducing the decomposition of chemical residues in contaminated water. Here, the nanoparticles are not directly involved in the chemical reaction but rather act as a catalyst, speeding up the conversion of the substances into harmless compounds.

“Nanoparticles such as these are already used as a catalyst in  in numerous areas of industry,” explains Salvador Pané, who has played a key role in advancing this research in his capacity as Senior Scientist. “Now, we’ve managed to show that they can also be useful for wastewater purification.”

Efficient removal of problem substances
Based on the example of various organic pigments, such as those used in the textile industry, the researchers are able to demonstrate the effectiveness of their approach. Picture left before treatment, right after treatment. Credit: ETH Zurich / Fajer Mushtaq

An 80 percent reduction

For their experiments, the researchers used aqueous solutions containing trace quantities of five common medications. The experiments confirmed that the nanoparticles can reduce the concentration of these substances in water by at least 80 percent. Fajer Mushtaq, a doctoral student in the group, underlines the importance of these results: “These  also included two compounds that can’t be removed using the conventional ozone-based method.”

“Remarkably, we’re able to precisely tune the catalytic output of the nanoparticles using magnetic fields,” explains Xiangzhong Chen, a postdoc who also participated in the project. The particles have a cobalt ferrite core surrounded by a bismuth ferrite shell. If an external alternating magnetic field is applied, some regions of the particle surface adopt positive electric charges, while others become negatively charged. These charges lead to the formation of reactive oxygen species in water, which break down the organic pollutants into harmless compounds. The magnetic nanoparticles can then be easily removed from water using , says Chen.

Positive responses from industry

The researchers believe that the new approach is a promising one, citing its easier technical implementation than that of ozone-based , for example. “The wastewater industry is very interested in our findings,” says Pané.

However, it will be some time before the method can be applied in practice, as it has been investigated only in the laboratory so far. At any rate, Mushtaq says that approval has already been given for a BRIDGE project jointly funded by the Swiss National Science Foundation and Innosuisse with a view to support the method’s transfer into practical applications. In addition, plans are already in place to establish a spin-off company, in which the researchers intend to develop their idea to market maturity.


Explore further

Chemists suggest a new method to synthesise titanium nanoparticles for water purification


More information: Fajer Mushtaq et al. Magnetoelectrically Driven Catalytic Degradation of Organics, Advanced Materials (2019). DOI: 10.1002/adma.201901378

Journal information: Advanced Materials
Provided by ETH Zurich

Platinum Nanoparticles Offer ‘Selective Treatment’ of Liver Cancer Cells


1-platinumnano
Non-oxidised platinum nanoparticles have virtually no toxic effect on normal cells (bottom left). Once inside liver cancer cells (top right), the platinum is oxidised, releasing its toxic effect. Credit: ETH Zurich / Helma Wennemers

Researchers at ETH Zurich recently demonstrated that platinum nanoparticles can be used to kill liver cancer cells with greater selectivity than existing cancer drugs.

In recent years, the number of targeted  has continued to rise. However, conventional chemotherapeutic agents still play an important role in cancer treatment. These include -based  that attack and kill . But these agents also damage healthy tissue and cause severe side effects. Researchers at ETH Zurich have now identified an approach that allows for a more selective cancer treatment with drugs of this kind.

Platinum can be cytotoxic when oxidised to platinum(II) and occurs in this form in conventional platinum-based chemotherapeutics. Non-oxidised platinum(0), however, is far less toxic to cells. Based on this knowledge, a team led by Helma Wennemers, Professor at the Laboratory of Organic Chemistry, and Michal Shoshan, a postdoc in her group, looked for a way to introduce platinum(0) into the , and only then for it to be oxidised to platinum(II). To this end, they used non-oxidised platinum nanoparticles, which first had to be stabilized with a peptide. They screened a library containing thousands of peptides to identify a peptide suitable for producing platinum nanoparticles (2.5 nanometres in diameter) that are stable for years.

Oxidised inside the cell

Tests with cancer cell cultures revealed that the platinum(0) nanoparticles penetrate into cells. Once inside the specific environment of liver cancer cells, they become oxidised, triggering the cytotoxic effect of platinum(II).

Studies with ten different types of human cells also showed that the toxicity of the peptide-coated nanoparticles was highly selective to liver cancer cells. They have the same toxic effect as Sorafenib, the most common drug used to treat primary liver tumours today. However, the nanoparticles are more selective than Sorafenib and significantly more so than the well-known chemotherapeutic Cisplatin. It is therefore conceivable that the nanoparticles will have fewer side effects than conventional medication.

Joining forces with ETH Professor Detlef Günther and his research group, Wennemers and her team were able to determine the platinum content inside the cells and their nuclei using special mass spectrometry. They concluded that the platinum content in the nuclei of liver cancer cells was significantly higher than, for instance, in colorectal cancer . The authors believe that the platinum(II) ions – produced by oxidation of the  in the  – enter the nucleus, and there release their toxicity.

“We are still a very long and uncertain way away from a new drug, but the research introduced a new approach to improve the selectivity of drugs for certain types of  – by using a selective activation process specific to a given cell type,” Wennemers says. Future research will expand the chemical properties of the nanoparticles to allow for greater control over their biological effects.

 Explore further: Gold Nanoparticles Delivery Platinum Warheads to Tumors

More information: Michal S. Shoshan et al. Peptide-Coated Platinum Nanoparticles with Selective Toxicity against Liver Cancer Cells, Angewandte Chemie International Edition (2018). DOI: 10.1002/anie.201813149

Read more at: https://phys.org/news/2019-02-platinum-nanoparticles-treatment-liver-cancer.html#jCp

Super-stable antinomy carbon composite anodes to boost potassium-ion battery storage performance


id51930_1

Potassium-ion batteries (PIBs) have been considered as promising alternatives to lithium-ion batteries due to the rich natural abundance of potassium (K) and similar redox potential with Li+/Li.

However, due to the large K ion radius and slow reaction dynamics, the previously reported PIB anode materials (carbon-based materials, alloy-based anodes such as tin and antimony, metal oxides, etc.) suffer from a low capacity and fast capacity decay.
In order to achieve a high capacity and excellent cycle stability for K storage process, rational design of the electrode materials and proper selection of the electrolytes should be considered simultaneously.
Recently, two research teams led by Prof. Chunsheng Wang and Prof. Michael R. Zachariah from the University of Maryland, College Park, have designed and fabricated a novel antimony (Sb) carbon composite PIB anode via a facile and scalable electrospray-assisted strategy and found that this anode delivered super high specific capacities as well as cycling stability in a highly concentrated electrolyte (4M KTFSI/EC+DEC).
This work has been published in Energy and Environmental Science (“Super Stable Antimony-carbon composite anodes for potassium-ion batteries”).

 

id51930_1
Figure 1. Schematic illustration of electrospray-assisted strategy for fabricating antimony @carbon sphere network electrode materials. (© Royal Society of Chemistry)
We have successfully fabricated a novel antimony carbon composite with small Sb nanoparticles uniformly confined in the carbon sphere network (Sb@CSN) via a facile and scalable electrospray-assisted strategy.
Such a unique nanostructure can effectively mitigate the deleteriously mechanical damage from large volume changes and provide a highly conductive framework for fast electron transport during alloy/de-alloy cycling process.
Alongside the novel structural design of the anode material, formation of a robust solid-electrolyte-interphase (SEI) on the anode is crucially important to achieve its long-term cycling stability.
The formation of a robust SEI on the anode material is determined by both the surface chemistries of active electrode materials as well as electrolyte compositions such as salt anion types and concentrations.
Therefore, designing a proper electrolyte is extremely important for the anode to achieve a high cycling stability.
In our study, we have for the first time developed a stable and safe electrolyte of highly concentrated 4M KTFSI/EC+DEC for PIBs to promote the formation of a stable and robust KF-rich SEI layer on an Sb@CSN anode, which guarantees stable electrochemical alloy/de-alloy reaction dynamics during long-time cycling process.
Cycling performance of antimony carbon sphere network electrode materials
Figure 2. Cycling performance of antimony carbon sphere network electrode materials at 200mA/g current density in the highly concentrated electrolyte (4M KTFSI/EC+DEC). (© Royal Society of Chemistry)
In the optimized 4M KTFSI/EC+DEC electrolyte, the Sb@CSN composite delivers excellent reversible capacity of 551 mAh/g at 100 mA/g over 100 cycles with a capacity decay of 0.06% per cycle from the 10st to 100th cycling and 504 mAh/g even at 200 mA/g after 220 cycling. This demonstrates the best electrochemical performances with the highest capacity and longest cycle life when compared with all K-ion batteries anodes reported to date.
The electrochemical reaction mechanism was further revealed by density functional theory (DTF) calculation to support such excellent Potassium-storage properties.
Capacity comparison of Sb@CSN anode with previous reported anodes in potassium ion batteries
Figure 3. Capacity comparison of Sb@CSN anode with previous reported anodes in potassium ion batteries. (© Royal Society of Chemistry)
In conclusion, these outstanding performances should be attributed to the novel nanostructure of Sb nanoparticles uniformly encapsulated into conductive carbon network and the formation of a more stable and robust KF-rich SEI layer on Sb@CSN in the optimized 4M KTFSI electrolyte.
These encouraging results will significantly promote the deep understanding of the fundamental electrochemistry in Potassium-ion batteries as well as rational development of efficient electrolyte systems for next generation high-performance Potassium-ion batteries.
Yong Yang, Research Associate, Prof. Zachariah Research Group, Department of Chemical and Environmental Engineering, University of California, Riverside

U of Manchester – Nobel-prize Winning Chemistry for Clean Energy Breakthrough used to Reduce the cost of Fuel Cells used in Renewable Energy Vehicles – Reduce harmful emissions from ICE’s


nobelenergynanoparticlesCredit: CC0 Public Domain

Scientists have used a Nobel-prize winning chemistry technique on a mixture of metals to potentially reduce the cost of fuel cells used in electric cars and reduce harmful emissions from conventional vehicles.

The researchers have translated a biological , which won the 2017 Nobel Chemistry Prize, to reveal atomic scale chemistry in metal . These materials are one of the most effective catalysts for energy converting systems such as fuel cells. It is the first time this technique has been for this kind of research.

The particles have a complex star-shaped geometry and this new work shows that the edges and corners can have different chemistries which can now be tuned to reduce the cost of batteries and catalytic convertors.

The 2017 Nobel Prize in Chemistry was awarded to Joachim Frank, Richard Henderson and Jacques Dubochet for their role in pioneering the technique of single particle reconstruction. This electron microscopy technique has revealed the structures of a huge number of viruses and proteins but is not usually used for metals.

Now, a team at the University of Manchester, in collaboration with researchers at the University of Oxford and Macquarie University, have built upon the Nobel Prize winning technique to produce three dimensional elemental maps of metallic nanoparticles consisting of just a few thousand atoms.

Published in the journal Nano Letters, their research demonstrates that it is possible to map different elements at the nanometre scale in three dimensions, circumventing damage to the particles being studied.

Metal nanoparticles are the primary component in many catalysts, such as those used to convert toxic gases in car exhausts. Their effectiveness is highly dependent on their structure and chemistry, but because of their incredibly small structure,  are required in order to provide image them. However, most imaging is limited to 2-D projections.

“We have been investigating the use of tomography in the electron microscope to map elemental distributions in three dimensions for some time,” said Professor Sarah Haigh, from the School of Materials, University of Manchester. “We usually rotate the particle and take images from all directions, like a CT scan in a hospital, but these particles were damaging too quickly to enable a 3-D image to be built up. Biologists use a different approach for 3-D imaging and we decided to explore whether this could be used together with spectroscopic techniques to map the different elements inside the nanoparticles.”

“Like ‘single particle reconstruction’ the technique works by imaging many particles and assuming that they are all identical in structure, but arranged at different orientations relative to the electron beam. The images are then fed in to a computer algorithm which outputs a three dimensional reconstruction.”

In the present study the new 3-D chemical imaging method has been used to investigate platinum-nickel (Pt-Ni) metal nanoparticles.

Lead author, Yi-Chi Wang, also from the School of Materials, added: “Platinum based nanoparticles are one of the most effective and widely used catalytic materials in applications such as fuel cells and batteries. Our new insights about the 3-D local chemical distribution could help researchers to design better catalysts that are low-cost and high-efficiency.”

“We are aiming to automate our 3-D chemical reconstruction workflow in the future”, added author Dr. Thomas Slater.”We hope it can provide a fast and reliable method of imaging nanoparticle populations which is urgently needed to speed up optimisation of nanoparticle synthesis for wide ranging applications including biomedical sensing, light emitting diodes, and solar cells.”

 Explore further: Video: The 2017 Nobel Prize in Chemistry: Cryo-electron microscopy explained

More information: Yi-Chi Wang et al. Imaging Three-Dimensional Elemental Inhomogeneity in Pt–Ni Nanoparticles Using Spectroscopic Single Particle Reconstruction, Nano Letters (2019). DOI: 10.1021/acs.nanolett.8b03768