Tag Archives: nanoparticles

Cheap Nano-Catalysts For Better Fuel Cells

Researchers at Daegu Gyeongbuk Institute of Science & Technology (DGIST) in Korea have developed nano-catalysts that can reduce the overall cost of clean energy fuel cells, according to a study published in the Journal of Applied Catalysis B: Environmental.

Polymer electrolyte membrane fuel cells (PEMFCs) transform the chemical energy produced during a reaction between hydrogen fuel and oxygen into electrical energy. While PEMFCs are a promising source of clean energy that is self-contained and mobile – much like the alkaline fuel cells used on the US Space Shuttle – they currently rely on expensive materials. Also, the substances used for catalysing these chemical reactions degrade, raising concerns about reusability and viability.

DGIST energy materials scientist Sangaraju Shanmugam and his team have developed active and durable catalysts for PEMFCs that can reduce the overall manufacturing costs. The catalysts were nitrogen-doped carbon nanorods with ceria and cobalt nanoparticles on their surfaces; essentially carbon nanorods containing nitrogen, cobalt and ceria. Ceria (CeO2), a combination of cerium and oxygen, is a cheap and environmentally friendly semiconducting material that has excellent oxygen reduction abilities.

The fibres were made using a technique known as electrospinning, in which a high voltage is applied to a liquid droplet, forming a charged liquid jet that then dries midflight into uniform, nanosized particles. The researchers’ analyses confirmed that the ceria and cobalt particles were uniformly distributed in the carbon nanorods and that the catalysts showed enhanced electricity-producing capacity.

The ceria-supported cobalt on nitrogen-doped carbon nanorod catalyst was found to be more active and durable than cobalt-only nitrogen-doped carbon nanorods and platinum/carbon. They were explored in two important types of chemical reactions for energy conversion and storage: oxygen reduction and oxygen evolution reactions.

The researchers conclude that ceria could be considered among the most promising materials for use with cobalt on nitrogen-doped carbon nanorods to produce stable catalysts with enhanced electrochemical activity in PEMFCs and related devices.

Source: https://www.dgist.ac.kr/

Better Treat Salmonella Than Face Cancer

An interdisciplinary team of three Virginia Tech faculty members affiliated with the Macromolecules Innovation Institute has created a drug delivery system that could radically expand cancer treatment options. The conventional cancer treatment method of injecting nanoparticle drugs into the bloodstream results in low efficacy. Due to the complexities of the human body, very few of those nanoparticles actually reach the cancer site, and once there, there’s limited delivery across the cancer tissue.

The new system created at Virginia Tech is known as Nanoscale Bacteria-Enabled Autonomous Drug Delivery System (NanoBEADS). Researchers have developed a process to chemically attach nanoparticles of anti-cancer drugs onto attenuated bacteria cells, which they have shown to be more effective than the passive delivery of injections at reaching cancer sites.

NanoBEADS has produced results in both in vitro (in tumor spheroids) and in vivo (in living mice) models showing up to 100-fold improvements in the distribution and retention of nanoparticles in cancerous tissues.This is a product of Bahareh Behkam, associate professor of mechanical engineering. Collaborators on this interdisciplinary team are Rick Davis, professor of chemical engineering, and Coy Allen, assistant professor of biomedical sciences and pathobiology in the Virginia-Maryland College of Veterinary Medicine.

You can make the most amazing drugs, but if you cannot deliver it where it needs to go, it cannot be very effective,” Behkam said. “By improving the delivery, you can enhance efficacy.

Humans have noticed, even as far back as Ancient Egypt, that cancer went into remission if the patient also contracted an infection like salmonella. Neither are ideal, but humans can treat salmonella infections more effectively than cancer.

In modern times, Allen said the idea of treating cancer with infections traces back to the late 1800s and has evolved into immunotherapy, in which doctors try to activate the immune system to attack cancerous cells. Of course, salmonella is harmful to humans, but a weakened version could in theory provide the benefits of immunotherapy without the harmful effects of salmonella infection. The concept is similar to humans receiving a weakened flu virus in a vaccine to build immunity.

The work, which combines expertise in mechanical engineering, biomedical engineering, chemical engineering, and veterinary medicine, was recently detailed in Advanced Science.

Source: https://vtnews.vt.edu/

Plastic Waste Desintegrates Into Nanoparticles

There is a considerable risk that plastic waste in the environment releases nano-sized particles known as nanoplastics, according to a new study from Lund University in Sweden. The researchers studied what happened when takeaway coffee cup lids, for example, were subjected to mechanical breakdown, in an effort to mimic the degradation that happens to plastic in the ocean.The majority of all marine debris is plastic. Calculations have shown that ten per cent of all plastic produced globally ends up in the sea. This plastic waste is subjected to both chemical and mechanical degradation. The sun’s UV rays contribute to the degradation, as do waves, which cause plastic waste to grind against stones on the water’s edge, against the sea floor or against other debris.

Is there a risk that this plastic waste disintegrates to the extent that nanoplastics are released? The research community is divided on whether the degradation process stops at slightly larger plastic fragmentsmicroplastics – or actually continues and creates even smaller particles. The researchers behind the study have now investigated this issue by subjecting plastic material to mechanical degradation under experimental conditions.

We have been able to show that the mechanical effect on the plastic causes the disintegration of plastic down to nano-sized plastic fragments,” says Tommy Cedervall, chemistry researcher at Lund University.

The emphasis of a number of other recent studies from the research community has been on microplastics and their increased distribution among organisms. There are now intense attempts to also identify nanoplastics in the environment. Last year, in an earlier study from Lund University, researchers showed that nano-sized plastic particles can enter the brains of fish and that this causes brain damage which probably disturbs fish behaviour.

It’s important to begin mapping what happens to disintegrated plastic in nature, concludes Tommy Cedervall.

Source: https://www.lunduniversity.lu.se/

Megalibrary To Boost Discovery of New Materials

Different eras of civilization are defined by the discovery of new materials, as new materials drive new capabilities. And yet, identifying the best material for a given application—catalysts, light-harvesting structures, biodiagnostic labels, pharmaceuticals and electronic devices—is traditionally a slow and daunting task. The options are nearly infinite, particularly at the nanoscale (a nanometer is one-billionth of a meter) where material propertiesoptical, structural, electrical, mechanical and chemical—can significantly change, even at a fixed composition.

A new study published this week in the Proceedings of the National Academy of Sciences (PNAS) supports the efficacy of a potentially revolutionary new tool developed at Northwestern University to rapidly test millions (even billions) of nanoparticles to determine the best for a specific use.

Laser-induced heating of nanoparticles on micropillars for carbon nanotube growth

When utilizing traditional methods to identify new materials, we have barely scratched the surface of what is possible,” said Northwestern’s Chad A. Mirkin, the study’s corresponding author and a world leader in nanotechnology research and its applications. “This research provides proof-of-concept—that this powerful approach to discovery science works.”

The novel tool utilizes a combinatorial library, or megalibrary, of nanoparticles in a very controlled way. (A combinatorial library is a collection of systematically varied structures encoded at specific sites on a surface). The libraries are created using Mirkin’s Polymer Pen Lithography (PPL) technique, which relies on arrays (sets of data elements) with hundreds of thousands of pyramidal tips to deposit individual polymerdots” of various sizes and composition, each loaded with different metal salts of interest, onto a surface. Once heated, these dots are reduced to metal atoms forming a single nanoparticle at fixed composition and size.

By going small, we create two advantages in high throughput materials discovery,” said Mirkin, the executive director of Northwestern’s International Institute for Nanotechnology (IIN). “First, we can pack millions of features into square-centimeter areas, creating a path for making the largest and most complex libraries, to date. Second, by working at the sub-100 nanometer-length scale, size can become a library parameter, and much of the action, for example, in the field of catalysis, is on this length scale.”

Source: https://news.northwestern.edu/

How To Manipulate And Move Cells With Light

Wits physicists demonstrate a new device for manipulating and moving tiny objects with light. When you shine a beam of light on your hand, you don’t feel much, except for a little bit of heat generated by the beam. When you shine that same light into a world that is measured on the nano– or micro scale, the light becomes a powerful manipulating tool that you can use to move objects around – trapped securely in the light.

Researchers from the Structured Light group from the School of Physics at the University of the Witwatersrand in Johannesburg, South Africa, have found a way to use the full beam of a laser light, to control and manipulate minute objects such as single cells in a human body, tiny particles in small volume chemistry, or working on future on-chip devices. While the specific technique, called holographic optical trapping and tweezing, is not new, the Wits Researchers found a way to optimally use the full force of the light – including vector light that was previously unavailable for this application. This forms the first vector holographic trap.

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Previously holographic traps were limited to particular classes of light (scalar light), so it is very exciting that we can reveal a holistic device that covers all classes of light, including replicating all previous trapping devices,” explains Professor Andrew Forbes, team leader of the collaboration and Distinguished Professor in the School of Physics where he heads up the Wits Structured Light Laboratory.

What we have done is that we have demonstrated the first vector holographic optical trapping and tweezing system. The device allows micrometer sized particles, such as biological cells, to be captured and manipulated only with light.”

Source: https://www.wits.ac.za/

Cheap High-Performance Catalysts For Hydrogen Electric Car

The industry has been traditionally deploying platinum alloys as catalysts for oxygen reduction, which is for example essential in fuel cells or metal-air batteries. Expensive and rare, that metal imposes strict restrictions on manufacture. Researchers at Ruhr-Universität Bochum (RUB) and Max-Planck-Institut für Eisenforschung in Germany have discovered an alloy made up of five elements that is noble metal-free and as active as platinum.  The catalytic properties of non-noble elements and their alloys are usually rather poor. To the researchers’ surprise, one alloy made up of five almost equally balanced components offer much better properties. This is because of the so-called high entropy effect. It causes multinary alloys to maintain a simple crystal structure.

Through the interaction of different neighbouring elements, new active centres are formed that present entirely new properties and are therefore no longer bound to the limited properties of the individual elements,” explains Tobias Löffler, PhD student at the RUB Chair of Analytical ChemistryCenter for Electrochemical Sciences headed by Professor Wolfgang Schuhmann. “Our research has demonstrated that this alloy might be relevant for catalysis.”

Headed by Professor Christina Scheu, the research team at the Max-Planck-Institut für Eisenforschung analysed the generated nanoparticles using transmission electron microscopy. RUB chemists determined their catalytic activity and compared it with that of platinum nanoparticles. In the process, they identified a system made of up five elements where the high entropy effect results in catalytic activity for an oxygen reduction that is similar to that of platinum. By optimising the composition further, they successfully improved the overall activity.

These findings may have far-reaching consequences for electrocatalysis in general,” surmises Wolfgang Schuhmann. The researchers are hoping to adapt the properties for any required reactions by taking advantage of the almost infinite number of possible combinations of the elements and modifications of their composition. “Accordingly, the application will not necessarily be limited to oxygen reduction,” says Ludwig. The research team has already applied for a patent.

The results are published in the journal Advanced Energy Materials.

Source: http://news.rub.de/

Toxic Cocktails Of Harmful Nanoparticles

Nanoparticles, which are found in thousands of everyday products due to their unique properties, can form toxic cocktails harmful to our cells, a study has found. In a study published in the journal Nanotoxicology, scientists showed that 72 per cent of cells died after exposure to a cocktail of nano-silver and cadmium ionsNanoparticles are becoming increasingly widespread in our environment. For example, silver nanoparticles have an effective antibacterial effect and can be found in refrigerators, sports clothes, cosmetics, tooth brushes, and water filters.

There is a significant difference between how the cells react when exposed to nanosilver alone and when they are exposed to a cocktail of nanosilver and cadmium ions, which are naturally found everywhere around us on Earth, according to the researchers from University of Southern Denmark (SDU). In the study, 72 per cent of the cells died, when exposed to both nanosilver and cadmiun ions. When exposed to nanosilver only, 25 per cent died. When exposed to cadmium ions only, 12 per cent died researchers said.

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The study was conducted on human liver cancer cells. The study indicates, that we need to take cocktail effects into account when trying to ascertain their effect on our health, said Frank Kjeldsen, a professor at SDU.

Products with nano particles are being developed and manufactured every day, but in most countries there are no regulations, so there is no way of knowing what and how many nanoparticles are being released into the environment,” said Kjeldsen.

Source: https://www.sdu.dk/

Nanoparticles Destroy Dental Plaque, Prevent Tooth Decay

Combine a diet high in sugar with poor oral hygiene habits and dental cavities, or caries, will likely result. The sugar triggers the formation of an acidic biofilm, known as plaque, on the teeth, eroding the surface. Early childhood caries is a severe form of tooth decay that affects one in every four children in the United States and hundreds of millions more globally. It’s a particularly severe problem in underprivileged populations.

Treatment with a nanoparticle and hydrogen peroxide (right panel) left little in the way of bacteria (in blue) or the sticky biofilm matrix (in red), making the combination a potent force against dental plaque

In a study published in Nature Communications, researchers led by Hyun (Michel) Koo of the University of Pennsylvania School of Dental Medicine in collaboration with David Cormode of Penn’s Perelman School of Medicine and School of Engineering and Applied Science used FDA-approved nanoparticles to effectively disrupt biofilms and prevent tooth decay in both an experimental human-plaque-like biofilm and in an animal model that mimics early-childhood caries. The nanoparticles break apart dental plaque through a unique pH-activated antibiofilm mechanism.

It displays an intriguing enzyme-like property whereby the catalytic activity is dramatically enhanced at acidic pH but is ‘switched off’ at neutral pH conditions,” says Koo, professor in Penn Dental Medicine’s Department of Orthodontics. “The nanoparticles act as a peroxidase, activating hydrogen peroxide, a commonly used antiseptic, to generate free radicals that potently dismantle and kill biofilms in pathological acidic conditions but not at physiological pH, thus providing a targeted effect.”

Because the caries-causing plaque is highly acidic, the new therapy is able to precisely target areas of the teeth harboring pathogenic biofilms without harming the surrounding oral tissues or microbiota. The particular iron-containing nanoparticle used in the experiments, ferumoxytol, is already FDA-approved to treat iron-deficiency, a promising indication that a topical application of the same nanoparticle, used at several-hundred-fold lower concentration, would also be safe for human use.

Source: https://penntoday.upenn.edu/

Nano Packets Of Genetic Code Seed Cells Against Brain Cancer

In a “proof of concept” study, scientists at Johns Hopkins Medicine say they have successfully delivered nano-size packets of genetic code called microRNAs to treat human brain tumors implanted in mice. The contents of the super-small containers were designed to target cancer stem cells, a kind of cellularseed” that produces countless progeny and is a relentless barrier to ridding the brain of malignant cells.

Nanoparticles releasing microRNAs (light blue) inside a human brain cancer cell

Brain cancer is one of the most widely understood cancers in terms of its genetic makeup, but we have yet to develop a good treatment for it,” says John Laterra, MD, PhD, professor of neurology, oncology and neuroscience at the Johns Hopkins University School of Medicine and a research scientist at the Kennedy Krieger Institute. “The resilience of cancer stem cells and the blood-brain barrier are major hurdles.

Blood that enters the brain is filtered through a series of vessels that act as a protective barrier. But this blood-brain barrier blocks molecular medicines that have the potential to revolutionize brain cancer therapy by targeting cancer stem cells, says Laterra.

To modernize brain tumor treatments, we need tools and methods that bypass the blood-brain barrier,” says Jordan Green, PhD, professor of biomedical engineering, ophthalmology, oncology, neurosurgery, materials science and engineering and chemical and biomolecular engineering at the Johns Hopkins University School of Medicine. “We need technology to safely and effectively deliver sensitive genetic medicines directly to tumors without damaging normal tissue.

A case in point, Green says, is glioblastoma, the form of brain cancer that Arizona Sen. John McCain is battling, which often requires repeated surgeries. Doctors remove the brain tumor tissue that they can see, but the malignancy often returns quickly, says Laterra. Most patients with glioblastoma live less than two years after diagnosis.

Results of the experiments were published online in Nano Letters.

Source: https://engineering.jhu.edu/

Nanoparticles Fom Tea Leaves Destroy 80% Of Lung Cancer Cells

Nanoparticles derived from tea leaves inhibit the growth of lung cancer cells, destroying up to 80% of them, new research by a joint Swansea University (UK) and Indian team has shown. The team made the discovery while they were testing out a new method of producing a type of nanoparticle called quantum dots.  These are tiny particles which measure less than 10 nanometres.  A human hair is 40,000 nanometres thick.

Although nanoparticles are already used in healthcare, quantum dots have only recently attracted researchers’ attention.  Already they are showing promise for use in different applications, from computers and solar cells to tumour imaging and treating cancerQuantum dots can be made chemically, but this is complicated and expensive and has toxic side effects.  The Swansea-led research team were therefore exploring a non-toxic plant-based alternative method of producing the dots, using tea leaf extract.

Tea leaves contain a wide variety of compounds, including polyphenols, amino acids, vitamins and antioxidants.   The researchers mixed tea leaf extract with cadmium sulphate (CdSO4) and sodium sulphide (Na2S) and allowed the solution to incubate, a process which causes quantum dots to form.   They then applied the dots to lung cancer cells. Tea leaves are a simpler, cheaper and less toxic method of producing quantum dots, compared with using chemicals, confirming the results of other research in the field. Quantum dots produced from tea leaves inhibit the growth of lung cancer cells.  They penetrated into the nanopores of the cancer cells and destroyed up to 80% of them.  This was a brand new finding, and came as a surprise to the team.

The research, published in “Applied Nano Materials”, is a collaborative venture between Swansea University experts and colleagues from two Indian universities.

Source: http://www.swansea.ac.uk/