Posts belonging to Category Universities

Light-activated Neurons Restore Paralysed Muscles

A new way to artificially control muscles using light, with the potential to restore function to muscles paralysed by conditions such as motor neuron disease and spinal cord injury, has been developed by scientists at UCL and King’s College London.

The technique involves transplanting specially-designed motor neurons created from stem cells into injured nerve branches. These motor neurons are designed to react to pulses of blue light, allowing scientists to fine-tune muscle control by adjusting the intensity, duration and frequency of the light pulses.

In the study, published this week in Science, the team demonstrated the method in mice in which the nerves that supply muscles in the hind legs were injured. They showed that the transplanted stem cell-derived motor neurons grew along the injured nerves to connect successfully with the paralyzed muscles, which could then be controlled by pulses of blue light.
neurons activate paralysed muscles
Following the new procedure, we saw previously paralysed leg muscles start to function,” says Professor Linda Greensmith of the MRC Centre for Neuromuscular Diseases at UCL’s Institute of Neurology, who co-led the study. “This strategy has significant advantages over existing techniques that use electricity to stimulate nerves, which can be painful and often results in rapid muscle fatigue. Moreover, if the existing motor neurons are lost due to injury or disease, electrical stimulation of nerves is rendered useless as these too are lost.”.


How To Force Cancer Cells To Self-Destruct

Using magnetically controlled nanoparticles to force tumour cells to ‘self-destruct’ sounds like science fiction, but could be a future part of cancer treatment, according to research from Lund University in Sweden. The point of the new technique is that it is much more targeted than trying to kill cancer cells with techniques such as chemotherapy.
cancer cells forced to self-destruct
The clever thing about the technique is that we can target selected cells without harming surrounding tissue. There are many ways to kill cells, but this method is contained and remote-controlled”, said Professor Erik Renström.
Chemotherapy can also affect healthy cells in the body, and it therefore has serious side-effects. Radiotherapy can also affect healthy tissue around the tumour”. Our technique, on the other hand, is able to attack only the tumour cells”, added Enming Zhang, one of the first authors of the study.
The research group at Lund University is not the first to try and treat cancer using supermagnetic nanoparticles. However, previous attempts have focused on using the magnetic field to create heat that kills the cancer cells. The problem with this is that the heat can cause inflammation that risks harming surrounding, healthy tissue. The new method, on the other hand, in which the rotation of the magnetic nanoparticles can be controlled, only affects the tumour cells that the nanoparticles have entered.


Nano Paper-Filters Remove Virus

Researchers at the Division of Nanotechnology and Functional Materials, Uppsala University – Sweden – have developed a paper filter, which can remove virus particles with an efficiency matching that of the best industrial virus filters. The paper filter consists of 100 percent high purity cellulose nanofibers, directly derived from nature.

Virus particles are very peculiar objects- tiny (about thousand times thinner than a human hair) yet mighty. Viruses can only replicate in living cells but once the cells become infected the viruses can turn out to be extremely pathogenic. Viruses can actively cause diseases on their own or even transform healthy cells to malignant tumors.
nanofibers block viruses
The illustration shows the nanofibers in white and the virus in green
Viral contamination of biotechnological products is a serious challenge for production of therapeutic proteins and vaccines. Because of the small size, virus removal is a non-trivial task, and, therefore, inexpensive and robust virus removal filters are highly demanded’, says Albert Mihranyan, Associate Professor at the Division of Nanotechnology and Functional Materials, Uppsala University, who heads the study.

The research was carried out in collaboration with virologists from the Swedish University of Agricultural Sciences/Swedish National Veterinary Institute and is published in the Advanced Healthcare Materials journal.

Solar Cells Used As Lasers

A relatively new type of solar cell based on a perovskite material – named for scientist Lev Perovski, who first discovered materials with this structure in the Ural Mountains in the 19th century – was recently pioneered by an Oxford research team led by Professor Henry Snaith. Commercial silicon-based solar cells – such as those seen on the roofs of houses across the country – operate at about 20% efficiency for converting the Sun’s rays into electrical energy. It’s taken over 20 years to achieve that rate of efficiency. Latest research finds that the trailblazing ‘perovskite’ material used in solar cells can double up as a laser, strongly suggesting the astonishing efficiency levels already achieved in these cells is only part of the journey. Scientists have demonstrated potential uses for this material in telecommunications and for light emitting devices.

Solarcells used as LasersPerovskite solar cells, the source of huge excitement in the research community, already lie just a fraction behind commercial silicon, having reached a remarkable 17% efficiency after a mere two years of research – transforming prospects for cheap large-area solar energy generation.
Now, researchers from Professor Sir Richard Friend’s group at Cambridge’s Cavendish Laboratory – working with Snaith’s Oxford group – have demonstrated that perovskite cells excel not just at absorbing light but also at emitting it. The new findings, recently published online in the Journal of Physical Chemistry Letters, show that these ‘wonder cells’ can also produce cheap lasers. By sandwiching a thin layer of the lead halide perovskite between two mirrors, the team produced an optically driven laser which proves these cells “show very efficient luminescence” – with up to 70% of absorbed light re-emitted.


A Step Towards Invisibility

Controlling and bending light around an object so it appears invisible to the naked eye is the theory behind fictional invisibility cloaks. It may seem easy in Hollywood movies, but is hard to create in real life because no material in nature has the properties necessary to bend light in such a way. Scientists have managed to create artificial nanostructures that can do the job, called metamaterials. But the challenge has been making enough of the material to turn science fiction into a practical reality. The work of Debashis Chanda at the University of Central Florida (UCF), however, may have just cracked that barrier. The cover story in the March edition of the journal Advanced Optical Materials, explains how Chanda and fellow optical and nanotech experts were able to develop a larger swath of multilayer 3-D metamaterial operating in the visible spectral range. They accomplished this feat by using nanotransfer printing, which can potentially be engineered to modify surrounding refractive index needed for controlling propagation of light.

Such large-area fabrication of metamaterials following a simple printing technique will enable realization of novel devices based on engineered optical responses at the nanoscale,” said Chanda, an assistant professor at UCF.

Stealth aricraft
By improving the technique, the team hopes to be able to create larger pieces of the material with engineered optical properties, which would make it practical to produce for real-life device applications. For example, the team could develop large-area metamaterial absorbers, which would enable fighter jets to remain invisible from detection systems.


How To Measure Risks From Nanomaterials In Contact With Cells

Scientists at the Center for Nanotechnology and Nanotoxicology at Harvard School of Public Health (HSPH) have discovered a fast, simple, and inexpensive method to measure the effective density of engineered nanoparticles in physiological fluids, thereby making it possible to accurately determine the amount of nanomaterials that come into contact with cells and tissue in culture. The new discovery will have a major impact on the hazard assessment of engineered nanoparticles, enabling risk assessors to perform accurate hazard rankings of nanomaterials using cellular systems. Furthermore, by measuring the composition of nanomaterial agglomerates in physiologic fluids, it will allow scientists to design more effective nano-based drug delivery systems for nanomedicine applications.
nanohazardThousands of consumer products containing engineered nanoparticles — microscopic particles found in everyday items from cosmetics and clothing to building materials — enter the market every year. Concerns about possible environmental health and safety issues of these nano-enabled products continue to grow with scientists struggling to come up with fast, cheap, and easy-to-use cellular screening systems to determine possible hazards of vast libraries of engineered nanomaterials. However, determining how much exposure to engineered nanoparticles could be unsafe for humans requires precise knowledge of the amount (dose) of nanomaterials interacting with cells and tissues such as lungs and skin

The biggest challenge we have in assessing possible health effects associated with nano exposures is deciding when something is hazardous and when it is not, based on the dose level. At low levels, the risks are probably miniscule,” said senior author Philip Demokritou, associate professor of aerosol physics in the Department of Environmental Health at HSPH. “The question is: At what dose level does nano-exposure become problematic? The same question applies to nano-based drugs when we test their efficiency using cellular systems. How much of the administered nano-drug will come in contact with cells and tissue? This will determine the effective dose needed for a given cellular response,” Demokritou said.


Cheap Batteries Last 3 Times Longer, Recharge in 10 minutes

Researchers at the University of Southernn California (USC) have developed a new lithium-ion battery design that uses porous silicon nanoparticles in place of the traditional graphite anodes to provide superior performance.

The new batteries — which could be used in anything from cellphones to hybrid cars — hold three times as much energy as comparable graphite-based designs and recharge within 10 minutes. The design, currently under a provisional patent, could be commercially available within two to three years.
silicon nanoparticlesOn the left, a vial of the silicon nanoparticles; on the right, silicon nanoparticles viewed under magnification
It’s an exciting research. It opens the door for the design of the next generation lithium-ion batteries,” said Chongwu Zhou, professor at the USC Viterbi School of Engineering, who led the team that developed the battery.

Zhou worked with USC graduate students Mingyuan Ge, Jiepeng Rong, Xin Fang and Anyi Zhang, as well as Yunhao Lu of Zhejiang University in China. Their research was published in Nano Research in January.


Contact Lens To See During Night

The first room-temperature light detector that can sense the full infrared spectrum has the potential to put heat vision technology into a contact lens. Unlike comparable mid- and far-infrared detectors currently on the market, the detector developed by University of Michigan engineering researchers doesn’t need bulky cooling equipment to work. Infrared vision may be best known for spotting people and animals in the dark and heat leaks in houses, but it can also help doctors monitor blood flow, identify chemicals in the environment and allow art historians to see Paul Gauguin’s sketches under layers of paint. Graphene, a single layer of carbon atoms, could sense the whole infrared spectrum — plus visible and ultraviolet light. But until now, it hasn’t been viable for infrared detection because it can’t capture enough light to generate a detectable electrical signal. With one-atom thickness, it only absorbs about 2.3 percent of the light that hits it. If the light can’t produce an electrical signal, graphene can’t be used as a sensor.
To overcome that hurdle, Zhong and Ted Norris, the Gerard A. Mourou Professor of Electrical Engineering and Computer Science, worked with graduate students to design a new way of generating the electrical signal.

infra red night visionWe can make the entire design super-thin,” said Zhaohui Zhong, assistant professor of electrical and computer engineering. “It can be stacked on a contact lens or integrated with a cell phone.
The challenge for the current generation of graphene-based detectors is that their sensitivity is typically very poor.”It’s a hundred to a thousand times lower than what a commercial device would require.” “Our work pioneered a new way to detect light“. “We envision that people will be able to adopt this same mechanism in other material and device platforms” Zhong said.

The device is already smaller than a pinky nail and is easily scaled down. Zhong suggests arrays of them as infrared cameras.


Watch Nanoparticles Grow

Danish scientists from Arhus University – Netherlands – , led by Dr. Dipanka Saha, have observed the growth of nanoparticles live. To obtain this result, the team used the DESY’s X-ray light source PETRA III, a German Synchrotron. The study shows how tungsten oxide nanoparticles are forming from solution. These particles are used for example for smart windows, which become opaque at the flick of a switch, and they are also used in particular solar cells.

watch nanoparticles growLeft: Structure of the ammonium metatungstate dissolved in water on atomic length scale. The octahedra consisting of the tungsten ion in the centre and the six surrounding oxygen ions partly share corners and edges. Right: Structure of the nanoparticles in the ordered crystalline phase. The octahedra exclusively share corners

The team around lead author Dr. Dipankar Saha from Århus University present their observations in the scientific journal “Angewandte Chemie – International Edition“.

Flexible E-readers In Your Pocket

Engineers would love to create flexible electronic devices, such as e-readers that could be folded to fit into a pocket. One approach involves designing circuits based on electronic fibers known as carbon nanotubes (CNTs) instead of rigid silicon chips.

But reliability is essential. Most silicon chips are based on a type of circuit design that allows them to function flawlessly even when the device experiences power fluctuations. However, it is much more challenging to do so with CNT circuits.

But now a team at Stanford has developed a process to create flexible chips that can tolerate power fluctuations in much the same way as silicon circuitry.
bendable smartphone
This is the first time anyone has designed flexible CNT circuits that have both high immunity to electrical noise and low power consumption, ” said Zhenan Bao, a professor of chemical engineering at Stanford.

In principle, CNTs should be ideal for making flexible electronic circuitry. These ultra-thin carbon filaments have the physical strength to take the wear and tear of bending and the electrical conductivity to perform any electronic task.

But until this recent work from the Stanford team, flexible CNT circuits didn’t have the reliability and power-efficiency of rigid silicon chips.

Huiliang (Evan) Wang, a graduate student in Bao’s lab, and Peng Wei, a previous postdoctoral scholar in Bao’s lab, were the lead authors of the paper. Bao’s team also included Yi Cui, an associate professor of materials science at Stanford, and Hye Ryoung Lee, a graduate student in his lab.
The Bao Lab reported its findings in the Proceedings of the National Academy of Sciences.