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Amazing Science: Material Science Postings

Amazing Science: Material Science Postings | Amazing Science | Scoop.it

Materials science, also known as materials engineering, is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This relatively new scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates elements of applied physics and chemistry. With significant media attention focused on nanoscience and nanotechnology in recent years, materials science is becoming more widely known as a specific and unique field of science and engineering.

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How to measure and control the temperature inside a living cell?

How to measure and control the temperature inside a living cell? | Amazing Science | Scoop.it

The familiar thermometer from a doctor’s office is slightly too big considering the average human skin cell is only 30 millionths of a meter wide. But the capability is significant; developing the right technology to gauge and control the internal temperatures of cells and other nanospaces might open the door to a number of defense and medical applications: better thermal management of electronics, monitoring the structural integrity of high-performance materials, cell-specific treatment of disease and new tools for medical research.

 

A team of researchers working on DARPA’s Quantum-Assisted Sensing and Readout (QuASAR) program recently demonstrated sub-degree temperature measurement and control at the nanometer scale inside living cells. To measure temperature, the researchers used imperfections engineered into diamond, known as nitrogen-vacancy (NV) color centers, as nanoscale thermometers. Each NV center can capture an electron, such that the center behaves like an isolated atom trapped in the solid diamond. Changes in temperature cause the lattice structure of the diamond to expand or contract, similar to the way the surface of a bridge does when exposed to hot or cold weather. These shifts in the lattice induce changes in the spin properties of the trapped atoms, which researchers measure using a laser-based technique. The result is that scientists can now monitor sub-degree variations over a large range of temperatures in both organic and inorganic systems at length scales as low as 200 nanometers. For a sense of scale, see: http://learn.genetics.utah.edu/content/begin/cells/scale/.

 

The diamond sensors are themselves only 100 nanometers in diameter. Each one contains multiple NV centers (the QuASAR team engineered 500 NV centers into each), and multiple sensors can be embedded in a single cell using nanowires. Given the extremely small size of the diamond sensors and their temperature sensitivity, researchers can accurately measure temperature within areas smaller than one percent of the total area of a cell.

 

The QuASAR team also demonstrated control and mapping of temperature gradients at the subcellular level by implanting gold nanoparticles into a human cell alongside the diamond sensors. The 100-nanometer-diameter nanoparticles were then heated using a separate laser. By varying the power of the heating laser and the concentration of gold nanoparticles, the researchers were able to modify and characterize (using the diamond sensors) the local thermal environment around the cell. In particular, they were able to verify that the heating was localized near the gold nanoparticles and that the cell did not experience an overall ambient rise in temperature.

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Transparent graphene-based display could enable contact lens computers

Transparent graphene-based display could enable contact lens computers | Amazing Science | Scoop.it

Augmented reality generated in the form of a contact lens, with embedded pixels, would have many advantages over a glasses-based design. Many companies are currently working on ways to build curved LCDs, or even flexible LCDs, that could be embedded into a contact. Unless you want a full-scale bionic vision implant which sends the data to the lens, a stand-alone LCD is not going to cut it. A group of researchers from the Ulsan National Institute of Science and Technology in Korea are now working on a solution to this this problem — the contact lens computer.


The Ulsan researchers had previously worked in an area seemingly unrelated to display technology. Their claim to fame was a graphene-based “nanoplatelet” material that was stable and conductive enough to act as a fuel cell cathode. These nanoplatelets could be separated into individual sheets by a process called ball milling. On larger scales, ball milling is typically used to uniformly grind powders with a small agitated ball bouncing around inside a closed vessel. Inside a mini ball mill, graphene can be mixed with various halogens, like chlorine or bromine, which then creep in between the graphene sheets to make a robust material.


The researchers were able to build miniature inorganic LEDs by connecting the graphene sheets together with silver nanowires into a hybrid structure. The flexible silver nanowires enabled the hybrid strucuture to maintain its high conductivity even when bent. The most important factor for using the hybrid graphene in a contact lens-based computer is its high transparency. Other transparent materials like indium tine oxide (ITO) become much less conductive when bent. When the hybrid LEDs were embedded into a regular soft contact and tested in a rabbit no ill effects were observed.


At this point the contact developed by the researchers is really just a single pixel display, but the goal of the effort is to build a device that can do everything that something like Google Glass can do. There are many forms a contact computer might take. Embedding all that hardware inside a transparent device is currently impossible. One shortcut might be to use a tether for power and communications, although that probably wouldn’t be too comfortable. Wireless options have already been developed, at least in crude form, and may ultimately be the way to go. Once the device is powered and connected, we might imagine some of the rudimentary essentials such a device might do. At a minimum, one task might be to maintain the display settings to locally to match the changing optics of the eye as they search for some stability in a detached and partially artificial world.


Via Kalani Kirk Hausman
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Graphene-based supercapacitors a step closer to commerical reality

Graphene-based supercapacitors a step closer to commerical reality | Amazing Science | Scoop.it

Graphene-based supercapacitors have already proven the equal of conventional supercapacitors – in the lab. But now researchers at Melbourne’s Monash University claim to have developed of a new scalable and cost-effective technique to engineer graphene-based supercapacitors that brings them a step closer to commercial development.

 

With their almost indefinite lifespan and ability to recharge in seconds, supercapacitors have tremendous energy-storage potential for everything from portable electronics, to electric vehicles and even large-scale renewable energy plants. But the drawback of existing supercapacitors has been their low energy density of around 5 to 8 Wh/liter, which means they either have to be exceedingly large or recharged frequently.

 

Professor Dan Li and his team at Monash University’s Department of Materials Engineering has created a graphene-based supercapacitor with an energy density of 60 Wh/liter, which is around 12 times higher than that of commercially available supercapacitors and in the same league as lead-acid batteries. The device also lasts as long as a conventional battery.

 

To maximize the energy density, the team created a compact electrode from an adaptive graphene gel film they had previously developed. To control the spacing between graphene sheets on the sub-nanometer scale, the team used liquid electrolytes, which are generally used as the conductor in conventional supercapacitors.

 

Unlike conventional supercapacitors that are generally made of highly porous carbon with unnecessarily large pores and rely on a liquid electrolyte to transport the electrical charge, the liquid electrolyte in Li’s team’s supercapacitor plays a dual role of conducting electricity and also maintaining the minute space between the graphene sheets. This maximizes the density without compromising the supercapcitor’s porosity, they claim.

 

To create their compact electrode, the researchers used a technique similar to one used in traditional paper making, which they say makes the process cost-effective and easily scalable for industrial applications.

 

"We have created a macroscopic graphene material that is a step beyond what has been achieved previously. It is almost at the stage of moving from the lab to commercial development," Professor Li said.

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asysan's curator insight, May 13, 2015 8:54 AM
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Spray-Assisted Layer-By-Layer Functionalization of PRINT Built-To-Order Nanomedicine

Spray-Assisted Layer-By-Layer Functionalization of PRINT Built-To-Order Nanomedicine | Amazing Science | Scoop.it

A new coating technology developed at MIT, combined with a novel nanoparticle-manufacturing technology developed at the University of North Carolina at Chapel Hill, may offer scientists a way to quickly mass-produce tailored nanoparticles that are specially coated for specific applications, including medicines and electronics. 

Using this new combination of the two existing technologies, scientists can produce very small, uniform particles with customized layers of material that can carry drugs or other molecules to interact with their environment, or even target specific types of cells. 

Creating highly reproducible batches of precisely engineered, coated nanoparticles is important for the safe manufacture of drugs and obtaining regulatory approval, says Paula Hammond, the David H. Koch Professor in Chemical Engineering at MIT and a member of MIT’s Koch Institute for Integrative Cancer Research.

“Everyone’s excited about nanomedicine’s potential, and there are some systems that are making it out to market, but people are also concerned about how reproducible each batch is. That’s especially critical for applications such as cancer therapies,” Hammond says. “Fortunately, we have combined two technologies that are at the forefront of addressing these issues and that show great promise for the future of nanomanufacturing.”

 

Hammond’s lab previously developed a layer-by-layer deposition technique for coating nanoparticle surfaces with alternating layers of drugs, RNA, proteins or other molecules of interest. Those coatings can also be designed to protect nanoparticles from being destroyed by the body’s immune system before reaching their intended targets. 

“It’s a very versatile platform for incorporating therapeutics,” Hammond says. However, the layer-by-layer application processes commonly used today to coat nanoparticles take too long to be useful for rapid, large-scale manufacture: For each layer, the particles must be soaked in a solution of the coating material, then spun in a centrifuge to remove excess coating. Applying each layer takes about an hour.

In the new study, the MIT researchers used a spray-based technique, which allows them to apply each layer in just a few seconds. This technology was previously developed in the Hammond lab and is now being commercialized by Svaya Nanotechnologies. 

Hammond combined this approach with a nanoparticle-manufacturing technology known as the PRINT (Particle Replication In Non-wetting Templates) platform, which was developed in the DeSimone lab at UNC and is now being commercialized by Liquidia Technologies. Liquidia focuses on using the PRINT platform to create novel nanotechnology-based health-care products, vaccines and therapeutics.  

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Giant surfactants provide a versatile platform for sub-10-nm nanostructure engineering

Giant surfactants provide a versatile platform for sub-10-nm nanostructure engineering | Amazing Science | Scoop.it

The engineering of structures across different length scales is central to the design of novel materials with controlled macroscopic properties. A research team recently introduced a unique class of self-assembling materials, which are built upon shape- and volume-persistent molecular nanoparticles and other structural motifs, such as polymers, and can be viewed as a size-amplified version of the corresponding small-molecule counterparts. Among them, “giant surfactants” with precise molecular structures have been synthesized by “clicking” compact and polar molecular nanoparticles to flexible polymer tails of various composition and architecture at specific sites.


Capturing the structural features of small-molecule surfactants but possessing much larger sizes, giant surfactants bridge the gap between small-molecule surfactants and block copolymers and demonstrate a duality of both materials in terms of their self-assembly behaviors. The controlled structural variations of these giant surfactants through precision synthesis further reveal that their self-assemblies are remarkably sensitive to primary chemical structures, leading to highly diverse, thermodynamically stable nanostructures with feature sizes around 10 nm or smaller in the bulk, thin-film, and solution states, as dictated by the collective physical interactions and geometric constraints.


The results suggest that this class of materials provides a versatile platform for engineering nanostructures with sub-10-nm feature sizes. These findings are not only scientifically intriguing in understanding the chemical and physical principles of the self-assembly, but also technologically relevant, such as in nanopatterning technology and microelectronics.

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"Champion" nanostructures are able to produce hydrogen in the most environmentally friendly and cheap manner

"Champion" nanostructures are able to produce hydrogen in the most environmentally friendly and cheap manner | Amazing Science | Scoop.it
EPFL and Technion researchers have figured out the 'champion' nanostructures able to produce hydrogen in the most environmentally friendly and cheap manner, by simply using daylight.

 

In the quest for the production of renewable and clean energy, photoelectrochemical cells (PECs) constitute a sort of a Holy Grail. PECs are devices able of splitting water molecules into hydrogen and oxygen in a single operation, thanks to solar radiation. "As a matter of fact, we've already discovered this precious chalice, says Michael Grätzel, Director of the Laboratory of Photonics and Interfaces (LPI) at EPFL and inventor of dye-sensitized photoelectrochemical cells. Today we have just reached an important milestone on the path that will lead us forward to profitable industrial applications."

By using transmission electron microscopy (TEM) techniques, researchers were able to precisely characterize the movement of the electrons through the cauliflower-looking nanostructures forming the iron oxide particles, laid on electrodes during the manufacturing process. "These measures have helped us understand the reason why we get performance differences depending on the electrodes manufacturing process", says Grätzel.

 

By comparing several electrodes, whose manufacturing method is now mastered, scientists were able to identify the "champion" structure. A 10x10 cm prototype has been produced and its effectiveness is in line with expectations. The next step will be the development of the industrial process to large-scale manufacturing. A European funding and the Swiss federal government could provide support for this last part.

 

Evidently, the long-term goal is to produce hydrogen – the fuel of the future – in an environmentally friendly and especially competitive way. For Michael Grätzel, "current methods, in which a conventional photovoltaic cell is coupled to an electrolyzer for producing hydrogen, cost 15 € per kilo at their cheapest. We're aiming at a € 5 charge per kilo".



Read more at: http://phys.org/news/2013-07-champion-nano-rust-solar-hydrogen.html#jCp

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By combining self-assembling DNA molecules with simple dye molecules, 3D DNA antenna harvests solar energy

By combining self-assembling DNA molecules with simple dye molecules, 3D DNA antenna harvests solar energy | Amazing Science | Scoop.it

Researchers at Chalmers have found an effective solution for collecting sunlight for artificial photosynthesis. By combining self-assembling DNA molecules with simple dye molecules, the researchers have created a system that resembles nature's own antenna system.

 

Artificial photosynthesis is one of the hot trends in energy research. A large number of the worlds' energy problems could be resolved if it were possible to recreate the ability plants have to transform solar energy into fuel. The Earth receives enough solar energy every hour to satisfy our energy needs for an entire year.

 

A research team at Chalmers University of Technology has made a nanotechnological breakthrough in the first step required for artificial photosynthesis. The team has demonstrated that it is possible to use self-assembling DNA molecules as scaffolding to create artificial systems that collect light. The results were recently published in the esteemed scientific Journal of the American Chemical Society. Scaffolding in plants and algae consists of a large number of proteins that organise chlorophyll molecules to ensure effective light collection. The system is complicated and would basically be impossible to construct artificially.

 

"It's all over if a bond breaks," says Jonas Hannestad, PhD of physical chemistry. "If DNA is used instead to organise the light-collecting molecules, the same precision is not achieved but a dynamic self-constructing system arises." With a system that builds itself, the researchers have begun to approach nature's method. If any of the light-collecting molecules break, it will be replaced with another one a second later. In this sense, it is a self-repairing system as opposed to if molecules had been put there by researchers with synthetic organic chemistry. The sun's light is moved to a reaction centre in plants and algae so they can synthesise sugars and other energy-rich molecules. "We can move energy to a reaction center, but we have not resolved how the reactions themselves are to take place there," says Bo Albinsson, professor of physical chemistry and head of the research team.

 

"This is actually the most difficult part of artificial photosynthesis. We have demonstrated that an antenna can easily be built. We have recreated that part of the miracle."

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Three-dimensional deep sub-diffraction optical beam lithography with 9 nm, useful for highly improved data storage

Three-dimensional deep sub-diffraction optical beam lithography with 9 nm, useful for highly improved data storage | Amazing Science | Scoop.it

The current nanofabrication techniques including electron beam lithography provide fabrication resolution in the nanometer range. The major limitation of these techniques is their incapability of arbitrary three-dimensional nanofabrication. This has stimulated the rapid development of far-field three-dimensional optical beam lithography where a laser beam is focused for maskless direct writing. However, the diffraction nature of light is a barrier for achieving nanometer feature and resolution in optical beam lithography. Here we report on three-dimensional optical beam lithography with 9 nm feature size and 52 nm two-line resolution in a newly developed two-photon absorption resin with high mechanical strength. The revealed dependence of the feature size and the two-line resolution confirms that they can reach deep sub-diffraction scale but are limited by the mechanical strength of the new resin. Our result has paved the way towards portable three-dimensional maskless laser direct writing with resolution fully comparable to electron beam lithography.

 

Compared with single-beam OBL, two-beam OBL utilizes a doughnut-shaped inhibition beam to inhibit the photopolymerization triggered by the writing beam at the doughnut ring, leading to reduced feature size and improved resolution. Although both focused writing and inhibition beams result in the spot size limited by diffraction, the fabricated feature size and resolution by two-beam OBL can break the limit defined by the diffraction spot size of the two focused beams. In fact, the smallest feature size and the highest resolution are limited by the mechanical strength of the solidified material, which can be far beyond the diffraction limit provided that an appropriate photoresin with high mechanical strength can be developed. But this breakthrough has not yet been achieved. Here, we demonstrate 3D deep sub-diffraction OBL with 9 nm (λ/42 for the wavelength of the inhibition beam) feature size and 52 nm (λ/7) two-line resolution in a resin that can efficiently harness two-photon polymerization (2PP) and single-photon inhibition.

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Hierarchically nanoporous frameworks of nanocrystalline metal oxides for exceptionally high CO2 adsorption

Hierarchically nanoporous frameworks of nanocrystalline metal oxides for exceptionally high CO2 adsorption | Amazing Science | Scoop.it

Researchers from Ulsan National Institute of Science and Technology (UNIST), S. Korea, developed a novel, simple method to synthesize hierarchically nanoporous frameworks of nanocrystalline metal oxides such as magnesia and ceria by the thermal conversion of well-designed metal-organic frameworks (MOFs).

 

The novel material developed by the UNIST research team has exceptionally high CO2 adsorption capacity which could pave the way to save the Earth from CO2 pollution.

 

Nanoporous materials consist of organic or inorganic frameworks with a regular, porous structure. Because of their uniform pore sizes they have the property of letting only certain substances pass through, while blocking others. Nanoporous metal oxide materials are ubiquitous in materials science because of their numerous potential applications in various areas, including adsorption, catalysis, energy conversion and storage, optoelectronics, and drug delivery.

 

While synthetic strategies for the preparation of siliceous nanoporous materials are well-established, non-siliceous metal oxide-based nanoporous materials still present challenges.

 

A description of the new research was published (Web) on May 7 in the Journal of the American Chemical Society. (Title: Nanoporous Metal Oxides with Tunable and Nanocrystalline Frameworks via Conversion of Metal-Organic Frameworks) This article will be also highlighted in the Editor's Choice of the journal Science.

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Sensing individual biomolecules with optical sensors inside nanoboxes

Sensing individual biomolecules with optical sensors inside nanoboxes | Amazing Science | Scoop.it

A single cell in our body is composed of thousands of millions of different biomolecules that work together in an extremely well-coordinated way. Likewise, many biological and biochemical reactions occur only if molecules are present at very high concentrations. Understanding how all these molecules interact with each other is key to advancing our knowledge in molecular and cell biology. This knowledge is of central and fundamental importance in the quest for the detection of the earliest stages of many human diseases. As such, one of ultimate goals in Life Sciences and Biotechnology is to observe how individual molecules work and interact with each other in these very crowded environments. Unfortunately, detecting one molecule amongst millions of neighbouring molecules has been technically impossible until now. The key to successfully detecting the single molecule lies in the conception and production of a working device that shrinks the observation region to a tiny size that is comparable to the size of the molecule itself, i.e. only a few nanometres.

 

Researchers at the Fresnel Institute in Marseille and ICFO-the Institute for Photonic Sciences in Barcelona report in Nature Nanotechnology the design and fabrication of the smallest optical device, capable of detecting and sensing individual biomolecules at concentrations that are similar to those found in the cellular context. The device called "antenna-in-a-box" consists on a tiny dimer antenna made out of two gold semi-spheres, separated from each other by a gap as small as 15nm. Light sent to this antenna is enormously amplified in the gap region where the actual detection of the biomolecule of interest occurs. Because amplification of the light is confined to the dimensions of the gap, only molecules present in this tiny region are detected. A second trick that the researchers used to make this device work was to embed the dimer antennas inside boxes also of nanometric dimensions. "The box screens out the unwanted "noise" of millions of other surrounding molecules, reducing the background and improving as a whole the detection of individual biomolecules.", explains Jerome Wenger from Fresnel Institute. When tested under different sample concentrations, this novel antenna-in-box device allowed for 1100-fold fluorescence brightness enhancement together with detection volumes down to 58 zeptoliters (1 zL = 10E-21L), i.e., the smallest observation volume in the world.

 

The antenna-in-a-box offers a highly efficient platform for performing a multitude of nanoscale biochemical assessments with single molecule sensitivity at physiological conditions. It could be used for ultrasensitive sensing of minute amounts of molecules, becoming an excellent early diagnosis device for biosensing of many disease markers. "It can also be used as an ultra-bright optical nanosource to illuminate molecular processes in living cells and ultimately visualize how individual biomolecules interact with each other. This brings us closer to the long awaited dream of biologists", concludes ICFO researcher Prof. Maria Garcia-Parajo.

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Marcus Taylor's curator insight, July 29, 2013 9:20 PM

This antenna-in-box is amazing stuff. I had never heard of a zeptoliter before. It will allow us to peer into cells and get feedback on treatments.

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Fine-tuning emission spectra from quantum dots by photon-correlation Fourier spectroscopy in solution

Fine-tuning emission spectra from quantum dots by photon-correlation Fourier spectroscopy in solution | Amazing Science | Scoop.it

New MIT analysis should enable development of improved color displays and biomedical monitoring systems. The new method — called photon-correlation Fourier spectroscopy in solution — makes it possible to extract single-particle spectral properties from a large group of particles. While it doesn’t tell you the spectral peak width of a specific particle, it does give you the average single-particle spectral width from billions of particles, revealing whether the individual particles produce pure colors or not.

In addition, the particles “are not isolated on a surface, but are in their natural environment, in a solution. With the traditional methods, there’s always a question: How much does the surface affect the results?

The method works by comparing pairs of photons emitted by individual particles. That doesn’t tell you the absolute color of any particular particle, but it does give a representative statistical measure of the whole collection of particles. It does this by illuminating the sample solution with a laser beam and detecting the emitted light at extremely short time scales. So while different particles are not differentiated in space, they can be differentiated in time, as they drift in and out of the narrow laser beam and are turned on by the beam.

By applying this method to the production of quantum dot nanocrystals, the MIT team can determine how well different methods of synthesizing the particles work.

“It was an open question whether the single-dot line widths were variable or not,” Cui says. Now, he and his colleagues can determine this for each variation in the fabrication process, and start to fine-tune the process to produce the most useful output for different applications.

In addition to computer displays, such particles have applications in biomedical research, where they are used as staining agents for different biochemicals. The more precise the colors of the particles are, the greater the number of different colored particles that can be used at once in a sample, each targeted to a different kind of biomolecule.

Using this method, the researchers were able to show that a widely used material for quantum dots, cadmium selenide, does indeed produce very pure colors. But, they found that other materials that could replace cadmium selenide or produce different colors, such as indium phosphide, can also have intrinsically very pure colors. Previously, this was an open question. 

Todd Krauss, a professor of chemistry at the University of Rochester who was not involved in this research, says the MIT team’s “approach is very clever and builds on what this group has done previously.” Measuring the line widths of individual particles is important, he says, in optimizing applications such as television displays and biological markers. He adds, “We should be able to make much better strides now that this technique is published, because of the ability to get single-particle line widths on many particles at once.”

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New crystals that glow in different colors may illuminate homes and offices as effectively as natural sunlight

New crystals that glow in different colors may illuminate homes and offices as effectively as natural sunlight | Amazing Science | Scoop.it

Minuscule crystals that glow different colors may be the missing ingredient for white LED lighting that illuminates homes and offices as effectively as natural sunlight.

 

Light-emitting diodes, better known as LEDs, offer substantial energy savings over incandescent and fluorescent lights and are easily produced in single colors such as red or green commonly used in traffic lights or children's toys. Developing an LED that emits a broad spectrum of warm white light on par with sunlight has proven tricky, however. LEDs, which produce light by passing electrons through a semiconductor material, often are coupled with materials called phosphors that glow when excited by radiation from the LED.

 

"But it's hard to get one phosphor that makes the broad range of colors needed to replicate the sun," said John Budai, a scientist in ORNL's Materials Science and Technology division. "One approach to generating warm-white light is to hit a mixture of phosphors with ultraviolet radiation from an LED to stimulate many colors needed for white light."

 

Budai is working with a team of scientists from University of Georgia and Oak Ridge and Argonne national laboratories to understand a new group of crystals that might yield the right blend of colors for white LEDs as well as other uses. Zhengwei Pan's group at UGA grew the nanocrystals using europium oxide and aluminum oxide powders as the source materials because the rare-earth element europium is known to be a dopant, or additive, with good phosphorescent properties.

 

"What's amazing about these compounds is that they glow in lots of different colors—some are orange, purple, green or yellow," Budai said. "The next question became: why are they different colors? It turns out that the atomic structures are very different."

 

Budai has been studying the atomic structure of the materials using x-rays from Argonne's Advanced Photon Source. Two of the three types of crystal structures in the group of phosphors had never been seen before, which can probably be attributed to the crystals' small size, Budai said.

 

"Only the green ones were a known crystal structure," Budai said. "The other two, the yellow and blue, don't grow in big crystals; they only grow with these atomic arrangements in these tiny nanocrystals. That's why they have different photoluminescent properties."

 

X-ray diffraction analysis is helping Budai and his collaborators work out how the atoms are arranged in each of the different crystal types. The different-colored phosphors exhibit distinct diffraction patterns when they are hit with x-rays, enabling researchers to analyze the crystal structure.

"What that means in terms of how the electrons around the atoms interact to make light is much harder," Budai said. "We haven't completely solved that yet. That's the continuing research. We have a lot of clues, but we don't know everything."

 

The knowledge gained through their atomic-scale analysis is helping the research team improve the phosphorescent crystals. Different factors in the growth process—temperature, powder composition, and types of gas used—can change the final product. A fundamental understanding of all the parameters could help the team to perfect the recipe and improve the crystals' ability to convert energy into light.

 

Advancing the material's luminescence efficiency is key to making it useful for commercial LED products and other applications; the new nanocrystals may turn out to have other practical photonic uses beyond phosphors for LEDs. Their ability to act as miniature "light pipes" when the crystal quality is high enough could lend them to applications in fiber-optic technologies, Budai said.

 

"You can keep growing the crystals and measuring them, or you can understand why it's doing what it's doing, and figure out how to make it better. That's what we're doing—basic research. We have to figure out nature first."

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Vloasis's curator insight, June 6, 2013 8:20 AM

It's rather exciting to be living in a time when new forms of light are being invented!

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How Squid and Octopus Might Point the Way to Nanotechnology-based Stealth Coatings

How Squid and Octopus Might Point the Way to Nanotechnology-based Stealth Coatings | Amazing Science | Scoop.it

"For a long time, scientists have been fascinated by the dramatic changes in color used by marine creatures like squids and octopuses, but they never quite understood the mechanism responsible for this. Only recently they found out that a neurotransmitter, acetylcholine, sets in motion a cascade of events that culminate in the addition of phosphate groups to a family of unique proteins called reflectins. This process allows the proteins to condense, driving the animal's color-changing process. The latest findings revealed that there is a nanoscale mechanism behind cephalopods' ability to change color."


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Ruth Obadia's curator insight, August 13, 2013 6:40 AM

Watch this amazing video of a camouflaging octopus

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Mini Lisa: Nanotechnique creates smallest "Mona Lisa" ever - Image is 30 microns wide!

Mini Lisa: Nanotechnique creates smallest "Mona Lisa" ever - Image is 30 microns wide! | Amazing Science | Scoop.it

The world’s most famous painting has now been created on the world’s smallest canvas. Researchers at the Georgia Institute of Technology have “painted” the Mona Lisa on a substrate surface approximately 30 microns in width – or one-third the width of a human hair. The team’s creation, the “Mini Lisa,” demonstrates a technique that could potentially be used to achieve nanomanufacturing of devices because the team was able to vary the surface concentration of molecules on such short-length scales.

 

The image was created with an atomic force microscope and a process called ThermoChemical NanoLithography (TCNL). Going pixel by pixel, the Georgia Tech team positioned a heated cantilever at the substrate surface to create a series of confined nanoscale chemical reactions. By varying only the heat at each location, Ph.D. Candidate Keith Carroll controlled the number of new molecules that were created. The greater the heat, the greater the local concentration. More heat produced the lighter shades of gray, as seen on the Mini Lisa’s forehead and hands. Less heat produced the darker shades in her dress and hair seen when the molecular canvas is visualized using fluorescent dye. Each pixel is spaced by 125 nanometers.

 

“By tuning the temperature, our team manipulated chemical reactions to yield variations in the molecular concentrations on the nanoscale,” said Jennifer Curtis, an associate professor in the School of Physics and the study’s lead author. “The spatial confinement of these reactions provides the precision required to generate complex chemical images like the Mini Lisa.”

 

Production of chemical concentration gradients and variations on the sub-micrometer scale are difficult to achieve with other techniques, despite a wide range of applications the process could allow. The Georgia Tech TCNL research collaboration, which includes associate professor Elisa Riedo and Regents Professor Seth Marder, produced chemical gradients of amine groups, but expects that the process could be extended for use with other materials. 

 

“We envision TCNL will be capable of patterning gradients of other physical or chemical properties, such as conductivity of graphene,” Curtis said. “This technique should enable a wide range of previously inaccessible experiments and applications in fields as diverse as nanoelectronics, optoelectronics and bioengineering.”

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Scientists make lightweight wire from carbon that may rival copper

Scientists make lightweight wire from carbon that may rival copper | Amazing Science | Scoop.it

Ten times lighter than copper and 30 times stronger — scientists at Cambridge University are hoping carbon nanotubes will replace copper as a way to conduct electricity in the future.

 

Scientists have made a strong, lightweight wire from carbon that might eventually be a rival to copper if its ability to conduct electricity can be improved, Cambridge University said.

 

They said it was the first time that the super-strong carbon wires, spun in a tiny furnace that looks like a cotton candy machine with temperatures above 1,800 F, had been made "in a usable form" a millimeter thick.

 

Krzysztof Koziol of the University's department of materials science and metallurgy told Reuters in a telephone interview that commercial applications were still years away but that "our target is to beat copper".

 

Wire made in the laboratory from carbon nanotubes (CNTs) — microscopic hollow cylinders composed of carbon atoms — is 10 times lighter than copper and 30 times stronger, the university said in a statement.


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New stamp-sized microfluidic chip sorts cells through a technique known as cell rolling

New  stamp-sized microfluidic chip sorts cells through a technique known as cell rolling | Amazing Science | Scoop.it

Early in 2012, MIT scientists reported on the development of a postage stamp-sized microchip capable of sorting cells through a technique, known as cell rolling, that mimics a natural mechanism in the body. The device successfully separated leukemia cells from cell cultures — but could not extract cells directly from blood. 

Now the group has developed a new microchip that can quickly separate white blood cells from samples of whole blood, eliminating any preliminary processing steps — which can be difficult to integrate into point-of-care medical devices. The hope, the researchers say, is to integrate the microchip into a portable diagnostic device that may be used to directly analyze patient blood samples for signs of inflammatory disease such as sepsis — particularly in regions of developing countries where diagnostic lab equipment is not readily available.

 

In their experiments, the scientists pumped tiny volumes of blood through the microchip and recovered a highly pure stream of white blood cells, virtually devoid of other blood components such as platelets and red blood cells. What’s more, the team found that the sorted cells were undamaged and functional, potentially enabling clinicians not only to obtain a white blood cell count, but also to use the cells to perform further genetic or clinical tests. 

Rohit Karnik, an associate professor of mechanical engineering at MIT, says the key to recovering such pure, functional cells lies in the microchip’s adaption of the body’s natural process of cell rolling. 

“We believe that because we’re using a very biomimetic process, the cells are happier,” Karnik says. “It’s a more gentle process, and the cells are functionally viable.”

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H. Fai Poon's curator insight, October 17, 2013 12:56 AM

Now someone make it into a cell sorter please.

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Nanowires can lift liquids without any external power

Nanowires can lift liquids without any external power | Amazing Science | Scoop.it

Imagine if you could drink a glass of water just by inserting a solid wire into it and sucking on it as though it were a soda straw. It turns out that if you were tiny enough, that method would work just fine — and wouldn’t even require the suction to start.

New research carried out at MIT and elsewhere has demonstrated for the first time that when inserted into a pool of liquid, nanowires — wires that are only hundreds of nanometers (billionths of a meter) across — naturally draw the liquid upward in a thin film that coats the surface of the wire. The finding could have applications in microfluidic devices, biomedical research and inkjet printers.

The phenomenon had been predicted by theorists, but never observed because the process is too small to be seen by optical microscopes; electron microscopes need to operate in a vacuum, which would cause most liquids to evaporate almost instantly. To overcome this, the MIT team used an ionic liquid called DMPI-TFSI, which remains stable even in a powerful vacuum. Though the observations used this specific liquid, the results are believed to apply to most liquids, including water.

The results are published in the journal Nature Nanotechnology by a team of researchers led by Ju Li, an MIT professor of nuclear science and engineering and materials science and engineering, along with researchers at Sandia National Laboratories in New Mexico, the University of Pennsylvania, the University of Pittsburgh, and Zhejiang University in China.

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Belinda Suvaal's curator insight, July 30, 2013 4:58 AM

selfhealing wires?

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Self-replicating space probes can spread throughout Milky Way in less than 10 million years

Self-replicating space probes can spread throughout Milky Way in less than 10 million years | Amazing Science | Scoop.it

Researchers from Edinburgh University have said 'self replicating' robotic space probes from alien civilisations could already have arrived in our solar system.

 

The probes, which mathematicians Duncan Forgan and Arwen Nicholson referred to in their paper 'Slingshot Dynamics for Self Replicating Probes and the Effect on Exploration Timescales', could be so hi-tech that they're invisible to human beings, the researchers said.

 

The two mathematicians analysed the possibility that probes could travel through space in a study published in the Journal of Astrobiology.

 

The paper raises the question of whether alien races could have used the gravity of stars to “slingshot” probes in order to gain speed: a technique humans already use for probes, such as the Voyager. The Voyager space probe uses a 'slingshot' technique but uses planets rather than stars as the Scotland-based mathematicians suggest.

 

The researchers also analysed how a fleet of probes could 'self replicate' and build new versions of themselves from dust and gas while traveling through space.

 

Dr Forgan said: "The fact we haven't seen probes of this type makes it difficult to believe that probe building civilisations have existed in the Milky Way in the last few million years."

 

According to the researchers' calculations alien probes would only need to travel at one tenth of the speed of light in order to explore every part of our galaxy within 10 million years.

 

The scientists said: 'We can conclude that a fleet of self-replicating probes can indeed explore the Galaxy in a sufficiently short time...orders of magnitude less than the age of the Earth.'

 

The research chimes with that Jacob Haqq-Misra who in 2011 suggested that alien objects could already exist in our solar system without us knowing - because we haven't looked hard enough for them.

 

The new piece of research once again raises the so-called 'Fermi Paradox' about the search for alien life.

 

The paradox, suggested by physicists Enrico Fermi and Michael H. Hart, is the apparent contradiction between the high probability extraterrestrial civilizations' existence and the lack of contact with such civilizations.

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Shaky sensor: a cantilever covered with bacteria shakes up and down as bacteria metabolize on its surface

Shaky sensor: a cantilever covered with bacteria shakes up and down as bacteria metabolize on its surface | Amazing Science | Scoop.it

A patient admitted to a hospital with a serious bacterial infection may have only a few hours to live. Figuring out which antibiotic to administer, however, can take days. Doctors must grow the microbes in the presence of the drugs and see whether they reproduce. Rush the process, and they risk prescribing ineffective antibiotics, exposing the patient to unnecessary side effects, and spreading antibiotic resistance. Now, researchers have developed a microscopic "tuning fork" that detects tiny vibrations in bacteria. The device might one day allow physicians to tell the difference between live and dead microbes—and enable them to recognize effective and ineffective antibiotics within minutes.

 

"It's a brilliant method," provided subsequent investigations confirm the researchers' interpretation of their data, says Martin Hegner, a biophysicist at Trinity College Dublin who was not involved in the work.

 

The research involves tiny, flexible bars called cantilevers that vibrate up and down like the prongs of a tuning fork when they receive an input of energy. Cantilevers are an important part of atomic force microscopy, which is useful for making atomic scale resolutions of surfaces for use in nanotechnology or atomic physics research. In this technique, a minute needle attached to a cantilever moves across a surface, and the deflection of the cantilever gives information about how atoms are arranged on the surface. It can even be used to shunt atoms around. More recently, however, they have been used without the needle as tiny oscillators, allowing scientists to investigate matter directly attached to the cantilever.

 

Biophysicist Giovanni Longo and colleagues at the Swiss Federal Institute of Technology in Lausanne and the University of Lausanne in Switzerland immersed these cantilevers in a liquid bacterial growth medium and monitored their movement using a laser. They found that the bare cantilever moved very slightly as a result of the thermal movement of the liquid molecules in the medium. They then covered both sides of the cantilever with Escherichia coli bacteria, which can cause food poisoning, and immediately found that the oscillations became much more pronounced. The researchers believe that chemical processes that occur inside the bacteria as they metabolize energy are driving the oscillation. "What we see is that if you have some sort of a moving system on the cantilever, you are going to induce a movement on the cantilever itself," Longo explains. "Exactly what kind of metabolic movement we see is something that we are still studying."

 

To determine if the cantilevers could detect the impact of drugs, the team added ampicillin, an antibiotic that the cultured bacteria were sensitive to. 

 

The size of the cantilever's oscillations decreased almost 20-fold within 5 minutes, the researchers report. Fifteen minutes later, the scientists flushed the antibiotic out with fresh growth medium, but the movement of the cantilever did not increase again. This, the researchers say, suggests that the antibiotic had killed the bacteria. When they used an ampicillin-resistant strain of E. coli, however, they found that the oscillations initially decreased but returned to normal within about 15 minutes, indicating that the microbes had recovered.

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New system of 2D structures to guide plasmonic waves at ultrashort wavelength for improved information processing

New system of 2D structures to guide plasmonic waves at ultrashort wavelength for improved information processing | Amazing Science | Scoop.it

Researchers at MIT have proposed a new system that combines ferroelectric materials — the kind often used for data storage — with graphene, a two-dimensional form of carbon known for its exceptional electronic and mechanical properties. The resulting hybrid technology could eventually lead to computer and data-storage chips that pack more components in a given area and are faster and less power-hungry.

The new system works by controlling waves called surface plasmons. These waves are oscillations of electrons confined at interfaces between materials; in the new system the waves operate at terahertz frequencies. Such frequencies lie between those of far-infrared light and microwave radio transmissions, and are considered ideal for next-generation computing devices.


The team’s new system allows waves to be concentrated at much smaller length scales, which could lead to a tenfold gain in the density of components that could be placed in a given area of a chip, Fang says. 

The team’s initial proof-of-concept device uses a small piece of graphene sandwiched between two layers of the ferroelectric material to make simple, switchable plasmonic waveguides. This work used lithium niobate, but many other such materials could be used, the researchers say. 

Light can be confined in these waveguides down to one part in a few hundreds of the free-space wavelength, Jin says, which represents an order-of-magnitude improvement over any comparable waveguide system. “This opens up exciting areas for transmitting and processing optical signals,” he says.

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First 3D printed battery that is the size of a grain of sand and comparable to current commercial batteries

First 3D printed battery that is the size of a grain of sand and comparable to current commercial batteries | Amazing Science | Scoop.it

A research team from Harvard University and the University of Illinois at Urbana-Champaign has demonstrated the ability to 3D print a battery. 3D printing can now be used to print lithium-ion microbatteries the size of a grain of sand. The printed microbatteries could supply electricity to tiny devices in fields from medicine to communications, including many that have lingered on lab benches for lack of a battery small enough to fit the device, yet provide enough stored energy to power them. Novel application of 3D printing could enable the development of miniaturized medical implants, compact electronics, tiny robots, and more.

 

To make the microbatteries, a team based at Harvard University and the University of Illinois at Urbana-Champaign printed precisely interlaced stacks of tiny battery electrodes, each less than the width of a human hair.

“Not only did we demonstrate for the first time that we can 3D-print a battery; we demonstrated it in the most rigorous way,” said Jennifer A. Lewis, senior author of the study, who is also the Hansjörg Wyss Professor of Biologically Inspired Engineering at the Harvard School of Engineering and Applied Sciences (SEAS), and a Core Faculty Member of the Wyss Institute for Biologically Inspired Engineering at Harvard University. Lewis led the project in her prior position at the University of Illinois at Urbana-Champaign, in collaboration with co-author Shen Dillon, an Assistant Professor of Materials Science and Engineering there.

 

The scientists realized they could pack more energy if they could create stacks of tightly interlaced, ultrathin electrodes that were built out of plane. For this they turned to 3D printing. 3D printers follow instructions from three-dimensional computer drawings, depositing successive layers of material—inks—to build a physical object from the ground up, much like stacking a deck of cards one at a time. The technique is used in a range of fields, from producing crowns in dental labs to rapid prototyping of aerospace, automotive, and consumer goods. Lewis’ group has greatly expanded the capabilities of 3D printing. They have designed a broad range of functional inks—inks with useful chemical and electrical properties. And they have used those inks with their custom-built 3D printers to create precise structures with the electronic, optical, mechanical, or biologically relevant properties they want.

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Vloasis's curator insight, June 19, 2013 7:05 PM

The implication of batteries so small that they cannot be seen definitely has a god-factor ring to it.

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Graphene can be made magnetic and effect can be switched on and off, opening avenue to graphene electronics

Graphene can be made magnetic and effect can be switched on and off, opening avenue to graphene electronics | Amazing Science | Scoop.it

In a report published in Nature Communications, a University of Manchester team led by Dr Irina Grigorieva shows how to create elementary magnetic moments in graphene and then switch them on and off. 

This is the first time magnetism itself has been toggled, rather than the magnetization direction being reversed. Modern society is unimaginable without the use of magnetic materials. They have become an integral part of electronic gadgets where devices including hard disks, memory chips and sensors employ miniature magnetic components. Each micro-magnet allows a bit of information (‘0’ or ‘1’) to be stored as two magnetization directions (‘north’ and ‘south’). This area of electronics is called spintronics. 

Despite huge advances, a big disappointment of spintronics has so far been its inability to deliver active devices, in which switching between the north and south directions is done in a manner similar to that used in modern transistors. This situation may dramatically change due to the latest discovery. 
 
Graphene is a chicken wire made of carbon atoms. It is possible to remove some of these atoms which results in microscopic holes called vacancies. The Manchester scientists have shown that electrons condense around these holes into small electronic clouds, and each of them behaves like a microscopic magnet carrying one unit of magnetism, spin. 

Dr Grigorieva and her team have shown that the magnetic clouds can be controllably dissipated and then condensed back. 

She explains: “This breakthrough allows us to work towards transistor-like devices in which information is written down by switching graphene between its magnetic and non-magnetic states. These states can be read out either in the conventional manner by pushing an electric current through or, even better, by using a spin flow. Such transistors have been a holy grail of spintronics.”

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Reversible Male Contraception With Gold Nanorods

Reversible Male Contraception With Gold Nanorods | Amazing Science | Scoop.it

Gold nanorods injected into mice testes heat up when excited by a near-infrared laser, killing sperm cells and damaging sperm-generating cells. Stained cross-sections of testis tissue show the damage seven days after the treatment (right). As a comparison, tubules in a testis injected with saline solution remains intact, with sperm and sperm-generating cells filling the middle of the tubules (left). An average tubule is 200 µm wide.


Sun, Jun Wang, and their colleagues developed the new method based on the long-known fact that heating testis tissue kills sperm cells. To do the heating, they turned to rod-shaped gold nanoparticles, which absorb infrared light and convert it into heat. Other researchers are developing ways to use these particles to heat up and kill tumor cells.

 

Sun’s team envisioned heating up testis tissue to different temperatures for certain effects. They hypothesized that with a low heat, the nanorods would kill sperm cells but not sperm-producing cells, thus causing reversible contraception because the treatment would preserve the ability to produce sperm. But with a high heat, the particles would permanently damage sperm-producing cells, shutting down sperm production and leading to sterilization.

 

Compared to hormonal methods, Sun says, the nanorod technique would have few side effects because it does not disrupt other hormonal pathways in the body. Also, the method would be less invasive than a surgical procedure like vasectomy. While the approach could be developed for humans in the future, Sun says, it could be immediately applied to sterilize domestic animals.

 

As a test of the method, the researchers studied male mice in six groups. Animals in each group got a single testicular injection of one of three solutions: a saline solution, a 105 µM gold nanorod solution, or a 145 µM gold nanorod solution. The scientists then exposed the animals’ testes to near-infrared laser light at one of two power densities for about 10 minutes.

Using an infrared camera, the team found that the temperature of the mice’s testes hit between 37 and 45 °C, depending on the nanorod concentration and laser power. High concentrations and high powers lead to high temperatures. Normal mice testis tissue hovers around 29 °C.

 

As a fertility test, the researchers let the mice mate at seven and 60 days after treatment and calculated fertility as the percentage of pregnancies per total number of mated females. After seven days, mice that had experienced testes temperatures of 37 or 40 °C were 10% as fertile as untreated mice. Their fertility recovered to 50% at 60 days. Meanwhile, testes temperatures of 45 °C permanently sterilized the animals; all of their sperm-generating cells had died, and they produced no pups.


Diana L. Blithe, who runs a male contraception research program at the National Institute of Child Health and Human Development, says that to develop the method for people the team would need to ensure that the gold nanoparticles don’t migrate to other organs and that the laser irradiation is precisely targeted on the testes.

 

The method is appropriate for companion animals, says John K. Amory, a contraception researcher at the University of Washington, Seattle. But men may find it undesirable due to possible testicular pain during and after the injections. He says that long-term studies of the sterilization form of the technique will be important to ensure that the method is, in fact, permanent.


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Boise State Scoop's curator insight, October 12, 2014 7:21 PM

Article examines the use of injecting gold nanorods to inactivate sperm-generating cells.

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Inhalable chemo-carrying nanoparticles target lung cancer directly

Inhalable chemo-carrying nanoparticles target lung cancer directly | Amazing Science | Scoop.it

U.S. researchers have developed a novel lung cancer treatment that uses nanoparticles to deliver an inhaled form of chemotherapy.

 

The scientists from Oregon State University, Rutgers University in New Jersey and the Cancer Institute of New Jersey developed "nanostructured lipid nanocarriers" that find cancer cells in the lung, attach to them and deliver drugs locally. With the inhaled substance, the patient receives an unadulterated form of the cancer drug compared with conventional intravenous administration, which can accumulate in other organs such as the liver or kidneys with toxic effects.

 

What's more, the nanoparticle comes with a bundle of small interfering RNA, siRNA, which helps silence certain genes to make the cancer cells more vulnerable to the drugs. Overall, the study showed 83% of the drug reaching its target in the lungs as opposed to 23% with the traditional approach, according to the article published in the Journal of Controlled Release.

 

"A drug delivery system that can be inhaled is a much more efficient approach, targeting just the cancer cells as much as possible," said co-author Oleh Taratula. "Other chemotherapeutic approaches only tend to suppress tumors, but this system appears to eliminate it."

 

The team has applied for a patent for the delivery platform, but human clinical trials will have to await further testing.

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