Heated magnetic nanoparticles may be the future of eradicating cancer cells without harming healthy tissue, according to research from the University of Buffalo, USA. The nanoparticles strike tumours with significant heat under a low magnetic field.
Hao Zeng, Professor of Physics at Buffalo, said, ‘The main accomplishment of our work is the greatly enhanced heating performance of nanoparticles under low-field conditions suitable for clinical applications. The best heating power we obtained is close to the theoretical limit, greatly surpassing some of the best performing particles that other research teams have produced.’
Targeting technologies would first direct nanoparticles to tumours within the patient’s body. Exposure to an alternating magnetic field would prompt the particles’ magnetic orientation to flip back and forth hundreds of thousands of times a second, causing them to warm up as they absorb energy from the electromagnetic field and convert it to thermal energy.
Two particles have been tested – manganese-cobalt-ferrite and zinc ferrite. While the manganese particle reached maximum heating power under high magnetic fields, the biocompatible zinc ferrite was efficieny under an ultra-low field.
While this form of treatment, known as magnetic nanoparticle hyperthermia, is not new, the Buffalo-designed particles are able to generate heat several times faster than the current standard.
Rice University nanoscientists have demonstrated a new catalyst that can convert ammonia into hydrogen fuel at ambient pressure using only light energy, mainly due to a plasmonic effect that makes the catalyst more efficient.
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A study from Rice’s Laboratory for Nanophotonics (LANP) in this week’s issue of Science describes the new catalytic nanoparticles, which are made mostly of copper with trace amounts of ruthenium metal. Tests showed the catalyst benefited from a light-induced electronic process that significantly lowered the “activation barrier,” or minimum energy needed, for the ruthenium to break apart ammonia molecules.
The research comes as governments and industry are investing billions of dollars to develop infrastructure and markets for carbon-free liquid ammonia fuel that will not contribute to greenhouse warming. But the researchers say the plasmonic effect could have implications beyond the “ammonia economy.”
Improving the sensitivity of light sensors or the efficiency of solar cells requires fine-tuning of light capturing. KAUST researchers have used complex geometry to develop tiny shell-shaped coverings that can increase the efficiency and speed of photodetectors.
Many optical-cavity designs have been investigated to seek efficiencies of light: either by trapping the electromagnetic wave or by confining light to the active region of the device to increase absorption. Most employ simple micrometer- or nanometer-scale spheres in which the light propagates around in circles on the inside of the surface, known as a whispering gallery mode.
Former KAUST scientist Der-Hsien Lien, now a postdoctoral researcher at the University of California, Berkeley, and his colleagues from China, Australia and the U.S. demonstrate that a more complex geometry comprising convex nanoscale shells improves the performance of photodetectors by increasing the speed at which they operate and enabling them to detect light from all directions.
Surface effects play an important role in the operation of some devices, explains KAUST principal investigator, Jr-Hau He. Nanomaterials offer a way to improve performance because of their high surface-to-volume ratio. “However, although nanomaterials have greater sensitivity in light detection compared to the bulk, the light–matter interactions are weaker because they are thinner,” describes He. “To improve this, we design structures for trapping light.”
Printed electronics use standard printing techniques to manufacture electronic devices on different substrates like glass, plastic films, and paper. Interest in this area is growing because of the potential to create cheaper circuits more efficiently than conventional methods. A new study by researchers at Soonchunhyang University in South Korea, published in AIP Advances, provides insights into the processing of copper nanoparticle ink with green laser light.
Kye-Si Kwon and his colleagues previously worked with silver nanoparticle ink, but they turned to copper (derived from copper oxide) as a possible low-cost alternative. Metallic inks composed of nanoparticles hold an advantage over bulk metals because of their lower melting points. Although the melting point of copper is about 1,083 degrees Celsius in bulk, according to Kwon, copper nanoparticles can be brought to their melting point at just 150 to 500 C—through a process called sintering. Then, they can be merged and bound together.
Kwon’s group concentrates on photonic approaches for heating nanoparticles by the absorption of light. “A laser beam can be focused on a very small area, down to the micrometer level,” explained Kwon and doctorate student Md. Khalilur Rahman. Heat from the laser serves two main purposes: converting copper oxide into copper and promoting the conjoining of copper particles through melting.
Advanced nuclear magnetic resonance (NMR) techniques at the U.S. Department of Energy’s Ames Laboratory have revealed surprising details about the structure of a key group of materials in nanotechology, mesoporous silica nanoparticles (MSNs), and the placement of their active chemical sites.
MSNs are honeycombed with tiny (about 2-15 nm wide) three-dimensionally ordered tunnels or pores, and serve as supports for organic functional groups tailored to a wide range of needs. With possible applications in catalysis, chemical separations, biosensing, and drug delivery, MSNs are the focus of intense scientific research.
“Since the development of MSNs, people have been trying to control the way they function,” said Takeshi Kobayashi, an NMR scientist with the Division of Chemical and Biological Sciences at Ames Laboratory. “Research has explored doing this through modifying particle size and shape, pore size, and by deploying various organic functional groups on their surfaces to accomplish the desired chemical tasks. However, understanding of the results of these synthetic efforts can be very challenging.”
In a paper to be published in a forthcoming issue of Nano, a team of researchers from Henan University have investigated the flame retardant performance of epoxy resin using a boron nitride nanosheet decorated with cobalt ferrite nanoparticles.
Polymers are widely used in our daily lives due to good physical and chemical stability, corrosion resistance and other superior properties. However, most polymers, due to their organic nature, are inherently flammable which is a potential threat to the safety of human life and property. In order to avoid or reduce the flammability of polymers, it is a good strategy to add flame retardants to the polymers.
Among them, two-dimensional (2-D) layered inorganic nanomateirals (nanosheets), represented by graphene oxide,molybdenum disulfide, and boron nitride nanosheets (BNNS), exhibit excellent flame retardant performance due to their good physical barrier effects. However, the flame retardance is not enough in the use of such 2-D inorganic flame retardants alone, and in particular, the ability to suppress toxic gases and smoke is weak.
Researchers at the University of Michigan and Seoul National University of Science and Technology have devised a new method for manufacturing devices that require precisely sized and positioned micro- and nanoscale particles. The technique is suitable for a wide array of assembly of micro- and nanoscale objects, and useful for electronic devices, and biological applications.
“It’s very hard to regulate things in the microscopic and nano-scale. You want the particles to sit there, and they won’t,” said Jay Guo, project leader and professor of electrical engineering and computer science. “We found a way to sort and localize large quantities of particles, and we can do it in a very scalable fashion.”
With this ability, engineers would be able to more efficiently manufacture and assemble photonic crystals, filtration devices and biological assays, create more sensitive sensing devices, and much more.
Guo has been working in the area of nanomanufacturing for decades, beginning with his work on roll-to-roll nanoimprint lithography. He switched to the current methodology of nanopatterning relying only on a sliced silicon wafer because of its relative simplicity and speed.
Gold nanoparticles brighten the fluorescent dyes researchers use to highlight and study proteins, bacteria and other cells, but the nanoparticles also introduce an artifact that makes the dye appear removed from the target it’s illuminating.
Now, a University of Michigan team has determined how to account for the discrepancy between where the fluorescent dye appears to be and where its actual position is.
When researchers want to understand how proteins interact with each other, how bacteria function or how cells grow and divide, they often use fluorescent dyes. This microscopy approach can be further enhanced with nanoparticles. But an artifact introduced by the nanoparticles makes the dye appear in the microscope as far as 100 nanometers removed from the proteinor bacteria to which it is directly bound.
This “scooching effect” presents a problem: 100 nanometers may seem like an infinitesimal measurement, but if a protein is itself only a nanometer in length, a researcher might not be able to tell whether a protein is interacting with another protein or just gazing at it from the equivalent of the opposite end of a football field.
Nature keeps a few secrets. While plenty of structures with low symmetry are found in nature, scientists have been confined to high-symmetry designs when synthesizing colloidal crystals, a valuable type of nanomaterial used for chemical and biological sensing and optoelectronic devices.
Now, research from Northwestern University and the University of Michigan has drawn back the curtain, showing for the first time how low-symmetry colloidal crystals can be made—including one phase for which there is no known natural equivalent.
“We’ve discovered something fundamental about the system for making new materials,” said Northwestern’s Chad A. Mirkin. “This strategy for breaking symmetry rewrites the rules for material design and synthesis.”
The research was published today (Jan. 13) in the journal Nature Materials.
A collaboration led by scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory has observed an unexpected phenomenon in lithium-ion batteries – the most common type of battery used to power cell phones and electric cars. As a model battery generated electric current, the scientists witnessed the concentration of lithium inside individual nanoparticles reverse at a certain point, instead of constantly increasing. This discovery, which was published on January 12 in the journal Science Advances, is a major step toward improving the battery life of consumer electronics.
“If you have a cell phone, you likely need to charge its battery every day, due to the limited capacity of the battery’s electrodes,” said Esther Takeuchi, a SUNY distinguished professor at Stony Brook University and a chief scientist in the Energy Sciences Directorate at Brookhaven Lab. “The findings in this study could help develop batteries that charge faster and last longer.”
Visualizing batteries on the nanoscale
Inside every lithium-ion battery are particles whose atoms are arranged in a lattice – a periodic structure with gaps between the atoms. When a lithium-ion battery supplies electricity, lithium ions flow into empty sites in the atomic lattice.
Berkeley Lab scientists show how tiny, metal-rich particles can be excited with a low-power laser for deep-tissue imaging
A research team has demonstrated how light-emitting nanoparticles, developed at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), can be used to see deep in living tissue.
The specially designed nanoparticles can be excited by ultralow-power laser light at near-infrared wavelengths considered safe for the human body. They absorb this light and then emit visible light that can be measured by standard imaging equipment.
The development and biological imaging application of these nanoparticles is detailed in a study published online Aug. 6 in Nature Communications.
Researchers hope to further develop these so-called alloyed upconverting nanoparticles, or aUCNPs, so that they can attach to specific components of cells to serve in an advanced imaging system to light up even single cancer cells, for example. Such a system may ultimately guide high-precision surgeries and radiation treatments, and help to erase even very tiny traces of cancer.
When you purchase anything from makeup to paint to sunscreen, chances are it contains engineered nanoparticles. These nanoscale materials have properties that are revolutionizing products—from medicine to agriculture to electronics. But eventually, those nanoparticles will reach natural environments. To use them safely and to their fullest potential, we need to know how they behave in real environments—and if that behavior leads to any unintended consequences.
Greg Lowry, professor of civil and environmental engineering at Carnegie Mellon University, studies how nanoparticles behave in and impact the environment. One way researchers have studied nanoparticle fate is by tracking gold nanoparticles—because they are stable and easy to find, or so researchers thought.
Recently, Lowry and Post-doctoral Researcher Astrid Avellan have made a breakthrough discovery: gold nanoparticles actually dissolve in freshwater environments, when they come into contact with mircroorganisms found on aquatic plants. During the dissolution process, gold ions are released, which will behave differently from the nanoparticles and could be toxic to some microorganisms. The study did not measure toxicity so this doesn’t mean gold nanoparticles are harmful—instead, by better understanding their behavior in biologically active environments, scientists can ultimately use this knowledge to design better nanomaterials. Their findings were published in Nature Nanotechnology.
Study: Pointed tips on aluminum ‘octopods’ increase catalytic reactivity.
Points matter when designing nanoparticles that drive important chemical reactions using the power of light.
Researchers at Rice University’s Laboratory for Nanophotonics (LANP) have long known that a nanoparticle’s shape affects how it interacts with light, and their latest study shows how shape affects a particle’s ability to use light to catalyze important chemical reactions.
In a comparative study, LANP graduate students Lin Yuan and Minhan Lou and their colleagues studied aluminum nanoparticles with identical optical properties but different shapes. The most rounded had 14 sides and 24 blunt points. Another was cube-shaped, with six sides and eight 90-degree corners. The third, which the team dubbed “octopod,” also had six sides, but each of its eight corners ended in a pointed tip.
Using straightforward chemistry and a mix-and-match, modular strategy, researchers have developed a simple approach that could produce over 65,000 different types of complex nanoparticles, each containing up to six different materials and eight segments, with interfaces that could be exploited in electrical or optical applications. These rod-shaped nanoparticles are about 55 nanometers long and 20 nanometers wide — by comparison a human hair is about 100,000 nanometers thick — and many are considered to be among the most complex ever made.
Technically, they already have. Nanoparticles are ultrafine units of matter that measure no more than 100 nanometers in length, width, or height. They have a part to play in fuel cells – and their potential replacement of combustion engines. Fuel cells produce electricity through a chemical reaction, and nanoparticles can serve as the catalysts that facilitate those reactions.
So we can all go home now, as that all makes perfect sense, right? Not quite.
These minuscule bits are particularly useful in industrial applications like fuel production, which require durable catalysts. Nanoparticles fit the bill because they have a relatively large surface-area-to-volume ratio, which means the reactions can happen faster (more surface to react) [source: Birch]. And because they’re so teeny tiny, you don’t have to use much.
But the nanoparticles currently in use aren’t the cheapest or the most durable. How is research changing that?
