Posts belonging to Category polymer



Nanoparticle Vaccine Against Cancer

Researchers from UT Southwestern Medical Center have developed a first-of-its-kind nanoparticle vaccine immunotherapy that targets several different cancer types.

The nanovaccine consists of tumor antigens tumor proteins that can be recognized by the immune system – inside a synthetic polymer nanoparticle. Nanoparticle vaccines deliver minuscule particulates that stimulate the immune system to mount an immune response. The goal is to help people’s own bodies fight cancer.


cancer-cells-

What is unique about our design is the simplicity of the single-polymer composition that can precisely deliver tumor antigens to immune cells while stimulating innate immunity. These actions result in safe and robust production of tumor-specific T cells that kill cancer cells,” said Dr. Jinming Gao, a Professor of Pharmacology and Otolaryngology in UT Southwestern’s Harold C. Simmons Comprehensive Cancer Center.

A study outlining this research, published online today in Nature Nanotechnology, reported that the nanovaccine had anti-tumor efficacy in multiple tumor types in mice.

The research was a collaboration between the laboratories of study senior authors Dr. Gao and Dr. Zhijian “James” Chen, Professor of Molecular Biology and Director of the Center for Inflammation Research. The Center was established in 2015 to study how the body senses infection and to develop approaches to exploit this knowledge to create new treatments for infection, immune disorders, and autoimmunity.

Source: http://www.utsouthwestern.edu/

Carbon Nanotubes Self-Assemble Into Tiny Transistors

Carbon nanotubes can be used to make very small electronic devices, but they are difficult to handle. University of Groningen (Netherlands) scientists, together with colleagues from the University of Wuppertal and IBM Zurich, have developed a method to select semiconducting nanotubes from a solution and make them self-assemble on a circuit of gold electrodes. The results look deceptively simple: a self-assembled transistor with nearly 100 percent purity and very high electron mobility. But it took ten years to get there. University of Groningen Professor of Photophysics and Optoelectronics Maria Antonietta Loi designed polymers which wrap themselves around specific carbon nanotubes in a solution of mixed tubes. Thiol side chains on the polymer bind the tubes to the gold electrodes, creating the resultant transistor.

polymer wrapped nanotube

In our previous work, we learned a lot about how polymers attach to specific carbon nanotubes, Loi explains. These nanotubes can be depicted as a rolled sheet of graphene, the two-dimensional form of carbon. ‘Depending on the way the sheets are rolled up, they have properties ranging from semiconductor to semi-metallic to metallic.’ Only the semiconductor tubes can be used to fabricate transistors, but the production process always results in a mixture.

We had the idea of using polymers with thiol side chains some time ago‘, says Loi. The idea was that as sulphur binds to metals, it will direct polymer-wrapped nanotubes towards gold electrodes. While Loi was working on the problem, IBM even patented the concept. ‘But there was a big problem in the IBM work: the polymers with thiols also attached to metallic nanotubes and included them in the transistors, which ruined them.’

Loi’s solution was to reduce the thiol content of the polymers, with the assistance of polymer chemists from the University of Wuppertal. ‘What we have now shown is that this concept of bottom-up assembly works: by using polymers with a low concentration of thiols, we can selectively bring semiconducting nanotubes from a solution onto a circuit.’ The sulphur-gold bond is strong, so the nanotubes are firmly fixed: enough even to stay there after sonication of the transistor in organic solvents.

Over the last years, we have created a library of polymers that select semiconducting nanotubes and developed a better understanding of how the structure and composition of the polymers influences which carbon nanotubes they select’, says Loi. The result is a cheap and scalable production method for nanotube electronics. So what is the future for this technology? Loi: ‘It is difficult to predict whether the industry will develop this idea, but we are working on improvements, and this will eventually bring the idea closer to the market.’

The results were published in the journal Advanced Materials on 5 April.
Source: http://www.rug.nl/
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3D Printing and Nanotechnology To Detect Toxic Liquids

Carbon nanotubes have made headlines in scientific journals for a long time, as has 3D printing. But when both combine with the right polymer, in this case a thermoplastic, something special occurs: electrical conductivity increases and makes it possible to monitor liquids in real time. This is a breakthrough for Polytechnique Montréal.

In practical terms, the result of this research, led by  Professor Daniel Therriault, looks like a cloth; but as soon as a liquid comes into contact with it, said cloth is able to identify its nature. In this case, it is ethanol, but it might have been another liquid. Such a process would be a terrific advantage to heavy industry, which uses countless toxic liquids.

carbon nanotubes

While deceptively simple, the recipe is so efficient that Professor Therriault protected it with a patent. In fact, a U.S. company is already looking at commercializing this material printable in 3D, which is highly conductive and has various potential applications. The first step: take a thermoplastic and, with a solvent, transform it into a solution so that it becomes a liquid. Second step: as a result of the porousness of this thermoplastic solution, carbon nanotubes can be incorporated into it like never before, somewhat like adding sugar into a cake mix. The result: a kind of black ink that’s fairly viscous and whose very high conductivity approximates that of some metals. Third step: this black ink, which is in fact a nanocomposite, can now move on to 3D printing. As soon as it comes out of the printing nozzle, the solvent evaporates and the ink solidifies. It takes the form of filaments slightly bigger than a hair. The manufacturing work can then begin.

Findings are described in the journal Small.

Source: http://www.polymtl.ca/

Nanotech Tatoo Maps Emotions

A new temporary “electronic tattoo” developed by Tel Aviv University that can measure the activity of muscle and nerve cells researchers is poised to revolutionize medicine, rehabilitation, and even business and marketing research. The tattoo consists of a carbon electrode, an adhesive surface that attaches to the skin, and a nanotechnology-based conductive polymer coating that enhances the electrode‘s performance. It records a strong, steady signal for hours on end without irritating the skin.

The electrode, developed by Prof. Yael Hanein, head of TAU‘s Center for Nanoscience and Nanotechnology, may improve the therapeutic restoration of damaged nerves and tissue — and may even lead to new insights into our emotional life. Prof. Hanein’s research was published last month in Scientific Reports and presented at an international nanomedicine program held at TAU. One major application of the new electrode is the mapping of emotion by monitoring facial expressions through electric signals received from facial muscles.

tattoo

The ability to identify and map people’s emotions has many potential uses,” said Prof. Hanein. “Advertisers, pollsters, media professionals, and others — all want to test people’s reactions to various products and situations. Today, with no accurate scientific tools available, they rely mostly on inevitably subjective questionnaires.

Researchers worldwide are trying to develop methods for mapping emotions by analyzing facial expressions, mostly via photos and smart software,” Prof. Hanein continued. “But our skin electrode provides a more direct and convenient solution.”

Source: https://www.aftau.org/

Nanoparticle Attacks Agressive Thyroid Cancer

Anaplastic thyroid cancer (ATC), the most aggressive form of thyroid cancer, has a mortality rate of nearly 100 percent and a median survival time of three to five months. One promising strategy for the treatment of these solid tumors and others is RNA interference (RNAi) nanotechnology, but delivering RNAi agents to the sites of tumors has proved challenging. Investigators at Brigham and Women’s Hospital, together with collaborators from Massachusetts General Hospital, have developed an innovative nanoplatform that allows them to effectively deliver RNAi agents to the sites of cancer and suppress tumor growth and reduce metastasis in preclinical models of ATC.

thyroid cancer

We call this a ‘theranostic’ platform because it brings a therapy and a diagnostic together in one functional nanoparticle,” said co-senior author Jinjun Shi, PhD, assistant professor of Anesthesia in the Anesthesia Department. “We expect this study to pave the way for the development of theranostic platforms for image-guided RNAi delivery to advanced cancers.”

RNAi, the discovery of which won the Nobel Prize in Physiology or Medicine 10 years ago, allows researchers to silence mutated genes, including those upon which cancers depend to grow and survive and metastasize. Many ATCs depend upon mutations in the commonly mutated cancer gene BRAF. By delivering RNAi agents that specifically target and silence this mutated gene, the investigators hoped to stop both the growth and the spread of ATC, which often metastasizes to the lungs and other organs.

When RNAi is delivered on its own, it is usually broken down by enzymes or filtered out by the kidneys before it reaches tumor cells. Even when RNAi agents make it as far as the tumor, they are often unable to penetrate or are rejected by the cancer cells. To overcome these barriers, the investigators used nanoparticles to deliver the RNAi molecules to ATC tumors. In addition, they coupled the nanoparticles with a near-infrared fluorescent polymer, which allowed them to see where the nanoparticles accumulated in a mouse model of ATC.

The results have appeared in the journal  Proceedings of the National Academy of Sciences.

Source: http://www.brighamandwomens.org/

Nanotechnologies Boost Electric Car Batteries

On a drizzly, gray morning in April, Yi Cui weaves his scarlet red Tesla in and out of Silicon Valley traffic. Cui, a materials scientist at Stanford University here, is headed to visit Amprius, a battery company he founded 6 years ago. It’s no coincidence that he is driving a battery-powered car, and that he has leased rather than bought it. In a few years, he says, he plans to upgrade to a new model, with a crucial improvement: “Hopefully our batteries will be in it.” Cui and Amprius are trying to take lithium–ion batteries—today’s best commercial technology—to the next level. They have plenty of company. Massive corporations such as Panasonic, Samsung, LG Chem, Apple, and Tesla are vying to make batteries smaller, lighter, and more powerful. But among these power players, Cui remains a pioneering force.
Unlike others who focus on tweaking the chemical composition of a battery’s electrodes or its charge-conducting electrolyte, Cui is marrying battery chemistry with nanotechnology. He is building intricately structured battery electrodes that can soak up and release charge-carrying ions in greater quantities, and faster, than standard electrodes can, without producing troublesome side reactions.

Tesla Model 3

“He’s taking the innovation of nanotechnology and using it to control chemistry,” says Wei Luo, a materials scientist and battery expert at the University of Maryland, College Park.
In a series of lab demonstrations, Cui has shown how his architectural approach to electrodes can domesticate a host of battery chemistries that have long tantalized researchers but remained problematic. Among them: lithium-ion batteries with electrodes of silicon instead of the standard graphite, batteries with an electrode made of bare lithium metal, and batteries relying on lithium-sulfur chemistry, which are potentially more powerful than any lithium-ion battery. The nanoscale architectures he is exploring include silicon nanowires that expand and contract as they absorb and shed lithium ions, and tiny egglike structures with carbon shells protecting lithium-rich silicon yolks.

Source: http://www.sciencemag.org/

Nano-Robots Enter Living Cells

Researchers have developed the world’s tiniest engine – just a few billionths of a metre in size – which uses light to power itself. The nanoscale engine, developed by researchers at the University of Cambridge, could form the basis of future nano-machines that can navigate in water, sense the environment around them, or even enter living cells to fight disease. The prototype device is made of tiny charged particles of gold, bound together with temperature-responsive polymers in the form of a gel. When the ‘nano-engine’ is heated to a certain temperature with a laser, it stores large amounts of elastic energy in a fraction of a second, as the polymer coatings expel all the water from the gel and collapse. This has the effect of forcing the gold nanoparticles to bind together into tight clusters. But when the device is cooled, the polymers take on water and expand, and the gold nanoparticles are strongly and quickly pushed apart, like a spring.

nano-motor

It’s like an explosion,” said Dr Tao Ding from Cambridge’s Cavendish Laboratory, and the paper’s first author. “We have hundreds of gold balls flying apart in a millionth of a second when water molecules inflate the polymers around them.
We know that light can heat up water to power steam engines,” said study co-author Dr Ventsislav Valev, now based at the University of Bath. “But now we can use light to power a piston engine at the nanoscale.”

The results are reported in the journal PNAS.

Source: http://www.cam.ac.uk/

Polymer Solar Cells, Low-Cost Alternative To Silicon

Polymer solar cells could be even cheaper and more reliable thanks to a breakthrough by researchers at Linköping University (Sweden) and the Chinese Academy of Sciences (CAS). This work is about avoiding costly and unstable fullerenes. In recent years, polymer solar cells have emerged as a low cost alternative to silicon solar cells. In order to obtain high efficiency, fullerenes are usually required in polymer solar cells to separate charge carriers. However, fullerenes are unstable under illumination, and form large crystals at high temperatures.

Now, a team of chemists led by Professor Jianhui Hou at the CAS has set a new world record for fullerene-free polymer solar cells by developing a unique combination of a polymer called PBDB-T and a small molecule called ITIC. With this combination, the sun’s energy is converted with an efficiency of 11%, a value that strikes most solar cells with fullerenes, and all without fullerenes. Feng Gao, together with his colleagues Olle Inganäs and Deping Qian at Linköping University, have characterized the loss spectroscopy of photovoltage (Voc), a key figure for solar cells, and proposed approaches to further improving the device performance.

fulleren160

We have demonstrated that it is possible to achieve high efficiency without using fullerene, and that such solar cells are also highly stable to heat. Because solar cells are working under constant solar radiation, good thermal stability is very important,” says Feng Gao, a physicist at the Department of Physics, Chemistry and Biology, Linköping University.

The combination of high efficiency and good thermal stability suggests that polymer solar cells, which can be easily manufactured using low-cost roll-to-roll printing technology, now come a step closer to commercialization,” says Feng Gao.
The results have been published in the journal Advanced Materials.

Source: http://liu.se/

Electronic Circuits Applied To Paper From A Pen

The electronics of the future will be printed. Flexible circuits can be produced inexpensively on foil or paper using printing processes and permit futuristic designs with curved diodes or input elements. This requires printable electronic materials that can be printed and retain a high level of conductivity during usage in spite of their curved surfaces. Some tried and tested materials include organic, conductive polymers and nanoparticles made of conductive oxides (TCOs). Research scientists at INMLeibniz-Institute for New Materials (Germany) have now combined the benefits of organic and inorganic electronic materials in a new type of hybrid inks. This allows electronic circuits to be applied to paper directly from a pen, for example. To create their hybrid inks, the research scientists coated nanoparticles made of metals with organic, conductive polymers and suspended them in mixtures of water and alcohol. These suspensions can be applied directly on paper or foil using a pen and they dry without any further processing to form electrical circuits.

ink to print electronics

Electrically conductive polymers are used in OLEDs, for example, which can also be manufactured on flexible substrates,” explains Tobias Kraus, Head of the research group Structure Formation at INM. “The combination of metal and nano-particles that we introduce here combines mechanical flexibility with the robustness of a metal and increases the electrical conductivity.”

The developers will be demonstrating their results and the possibilities they offer at stand B46 in hall 2 at this year’s Hanover Trade Fair as part of the leading trade show Research & Technology which takes place from 25th to 29th April.

Source: http://www.leibniz-inm.de/

Artificial Molecules Revolutionize 3D Printing

Scientists at ETH Zurich and IBM Research Zurich have developed a new technique that enables for the first time the manufacture of complexly structured tiny objects joining together microspheres. The objects have a size of just a few micrometres and are produced in a modular fashion, making it possible to program their design in such a way that each component exhibits different physical properties. After fabrication, it is also very simple to bring the micro-objects into solution. This makes the new technique substantially different from micro 3D printing technology. With most of today’s micro 3D printing technologies, objects can only be manufactured if they consist of a single material, have a uniform structure and are attached to a surface during production.

3D printing process ETHArtificial molecules. The individual components are marked with different fluorescent dyes (molecule size: 2-7 micrometres; compilation of microscopic images)

To prepare the micro-objects, the ETH and IBM researchers use tiny spheres made from a polymer or silica as their building blocks, each with a diameter of approximately one micrometre and different physical properties. The scientists are able to control the particles and arrange them in the geometry and sequence they like.

The structures that are formed occupy an interesting niche in the size scale: they are much larger than your typical chemical or biochemical molecules, but much smaller than typical objects in the macroscopic world. “Depending on the perspective, it’s possible to speak of giant molecules or micro-objects,” says Lucio Isa, Professor for Interfaces, Soft matter and Assembly at ETH Zurich. He headed the research project together with Heiko Wolf, a scientist at IBM Research. “So far, no scientist has succeeded in fully controlling the sequence of individual components when producing artificial molecules on the micro scale,” says Isa.

Source: https://www.ethz.ch/

Transparent Wood Brightens Homes

When it comes to indoor lighting, nothing beats the sun’s rays streaming in through windows. Soon, that natural light could be shining through walls, too. Scientists from the KTH Royal Institute of Technology (Sweden) have developed transparent wood that could be used in building materials and could help home and building owners save money on their artificial lighting costs. Their material, reported in ACS’ journal Biomacromolecules, also could find application in solar cell windows.

transparent wood

Homeowners often search for ways to brighten up their living space. They opt for light-colored paints, mirrors and lots of lamps and ceiling lights. But if the walls themselves were transparent, this would reduce the need for artificial lighting — and the associated energy costs. Recent work on making transparent paper from wood has led to the potential for making similar but stronger materials. Lars Berglund and colleagues from KTH the wanted to pursue this possibility.

The researchers removed lignin from samples of commercial balsa wood. Lignin is a structural polymer in plants that blocks 80 to 95 percent of light from passing through. But the resulting material was still not transparent due to light scattering within it. To allow light to pass through the wood more directly, the researchers incorporated acrylic, often known as Plexiglass. The researchers could see through the resulting material, which was twice as strong as Plexiglass. Although the wood isn’t as crystal clear as glass, its haziness provides a possible advantage for solar cells. Specifically, because the material still traps some light, it could be used to boost the efficiency of these cells, the scientists note.

Source: http://www.acs.org/
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https://www.kth.se/

Flexible Skin Cloaks Objects, Avoids Radar

Iowa State University engineers have developed a new flexible, stretchable and  tunablemetaskin” that uses rows of small, liquid-metal devices to cloak an object from the sharp eyes of radar. The meta-skin takes its name from metamaterials, which are composites that have properties not found in nature and that can manipulate electromagnetic waves. By stretching and flexing the polymer meta-skin, it can be tuned to reduce the reflection of a wide range of radar frequencies.

The journal Scientific Reports recently reported the discovery online. Lead authors from Iowa State’s department of electrical and computer engineering are Liang Dong, associate professor; and Jiming Song, professor. Co-authors are Iowa State graduate students Siming Yang, Peng Liu and Qiugu Wang; and former Iowa State undergraduate Mingda Yang. The National Science Foundation and the China Scholarship Council have partially supported the project.

flexible skin

It is believed that the present meta-skin technology will find many applications in electromagnetic frequency tuning, shielding and scattering suppression,” the engineers wrote in their paper.

Source: http://www.news.iastate.edu/