Articles from January 2017

How To Track Stem Cells In The Body

Rice University researchers have synthesized a new and greatly improved generation of contrast agents for tagging and real-time tracking of stem cells in the body. The agent combines ultrashort carbon nanotubes and bismuth clusters that show up on X-rays taken with computed tomography (CT) scanners. The stable compound performs more than eight times better than the first-generation material introduced in 2013, according to the researchers.

An improved compound of bismuth and carbon nanotubes called Bi4C@US-tubes, developed at Rice University could enhance the ability to track stem cells as they move through the body and target diseases

The primary application will be to track them in stem-cell therapies to see if the cells are attracted to the site of disease — for example, cancer — and in what concentration,” said Rice chemist Lon Wilson of the compound the researchers call Bi4C@US-tubes.

Magnetic resonance imaging is currently used for that purpose and it works quite well, but X-ray technology in the clinic is much more available,” he said. “It’s faster and cheaper, and it could facilitate preclinical studies to track stem cells in vivo.”

Bismuth is used in cosmetics, pigments and pharmaceuticals, notably as the active ingredient in pink bismuth (aka Pepto-Bismol), an antacid. For this application, bismuth nanoclusters developed by the lab of Rice chemist Kenton Whitmire, a co-author of the paper, are combined with carbon nanotubes chemically treated to shorten them to between 20 and 80 nanometers and add defects to their side walls. The nanoclusters, which make up about 20 percent of the compound, appear to strongly attach to the nanotubes via these defects.

When introduced into stem cells, the treated nanotubes become easy to spot, Wilson said. “It’s very interesting to see a cell culture that is opaque to X-rays. They’re not as dark as bone (which X-rays cannot penetrate), but they’re really dark when they’re loaded with these agents.”

The process developed by Wilson’s team and colleagues at CHI St. Luke’s Health-Baylor St. Luke’s Medical Center and Baylor College of Medicine is detailed this month in the American Chemical Society journal ACS Applied Materials and Interfaces.


‘Protective’ DNA strands are shorter in adults who had more infections as infants

New research indicates that people who had more infections as babies harbor a key marker of cellular aging as young adults: the protective stretches of DNA which “cap” the ends of their chromosomes are shorter than in adults who were healthier as infants.

TELOMERESThe 46 chromosomes of the human genome, with telomeres highlighted in white

These are important and surprising findings because — generally speaking — shorter chromosome ‘caps’ are associated with a higher burden of disease later in life,” said lead author Dan Eisenberg, an assistant professor of anthropology at the University of Washington.

The ‘caps’ Eisenberg and his co-authors measured are called telomeres. These are long stretches of DNA at the ends of our chromosomes, which protect our genes from damage or improper regulation. One Nobel Prize-winning scientist who studies telomeres has compared them to aglets — the plastic or metal sheath covering ends of shoelaces. When aglets wear down, the shoelace is exposed to fraying and degradation from environmental forces.

Like aglets, telomeres don’t last forever. In most of our cells, telomeres get shorter each time that cell divides. And when they get too short, the cell either quits dividing or dies.

That makes telomere length particularly important for the cells of our immune system, especially the white blood cells circulating in our bloodstream. When activated against a pathogen, white blood cells undergo rapid rounds of cell division to raise a defensive force against the infectious invader. But if telomeres in white blood cells are already too short, the body may struggle to mount an effective immune response.

Many studies — in laboratory animals and humans — have associated shorter telomeres with poor health outcomes, especially in adults,” said Eisenberg. But few studies have addressed whether or not events early in a person’s life might affect telomere length. To get at this question, Eisenberg turned to the Cebu Longitudinal Health and Nutrition Survey, which has tracked the health of over 3,000 infants born in 1983-1984 in Cebu City in the Philippines. Researchers collected detailed data every two months from mothers on the health and feeding habits of their babies up through age two. Mothers reported how often their babies had diarrhea — a sign of infection — as well as how often they breastfed their babies. As these babies grew up, scientists collected additional health data during follow-up surveys over the next 20 years. In 2005, 1,776 of these offspring donated a blood sample. By then, they were 21- or 22-year-old young adults.

Eisenberg measured telomere length in cells from those blood samples. He then combined the data on adult telomere length with information about their health and feeding habits as babies. He found that babies with higher reported cases of diarrhea at 6 to 12 months also had the shortest telomeres as adults.

The findings have been published in the American Journal of Human Biology.


Understanding The Risks Of Nanotechnology

When radioactive materials were first introduced into society, it took a while before scientists understood the risks. The same is true of nanotechnology today, according to Dr Vladimir Baulin, from University Rovira i Virgili, in Tarragona, Spain, who together with colleagues has shown for the first time how nanoparticles can cross biological – or lipidmembranes in a paper published in the journal Science Advances
Nanotechnology is all around us, in building materials, in toothpaste and in cleaning products. Across Europe, hundreds of institutions are working together to look at how to monitor exposure, manage the risks and advise on what regulations may be needed under the EU’s NanoSafety Cluster.

nanoparticles effects on lipids

This is the first observation to show directly how tiny gold nanoparticles can cross a lipid bilayer (main part of a biological membrane). This process was quantified and the time of each step was estimated. The lipid membrane is the ultimate barrier protecting cells from the outside environment and if the nanoparticles can cross this barrier they may go into cells.’

‘Dr Jean-Baptiste Fleury (from Saarland University in Germany) designed a special set-up with two chambers separated by a lipid bilayer, which contained fluorescent lipids (fat molecules). Non-fluorescent nanoparticles were added to only one of the chambers. In this set-up, nanoparticles became visible only when they touched the fluorescent bilayer and exchanged lipids with it. If one sees the fluorescent nanoparticle in the second chamber, this means it was in contact with the bilayer and it crossed the bilayer from one chamber to another. This was the proof. In addition, the process of translocation was quantified and the time of the crossing was estimated as milliseconds.’

All biological objects, biomolecules, proteins that exist in living organisms evolved over billions of years to adapt to each other. Nanoparticles which are synthesised in the laboratory are thus considered by a living organism as something foreign. It is a big challenge to make them compatible and not toxic.’ ‘I would count the applications of nanoparticles as starting from the 1985 Nobel Prize for the discovery of fullerenes (molecules of hollow football-shaped carbon). This was the start of the nanoparticle boom.’

This is becoming urgent because nanoparticles and nanotechnology in general are entering our lives. Now it is possible to synthesise nanomaterials with precise control, fabricate nanostructures on surfaces and do precise tailoring of the properties of nanoparticles.

‘It is becoming quite urgent to understand the exact mechanisms of nanotoxicity and make a classification depending on the mechanism. Radioactivity or X-rays entered our lives the same way. It took time until researchers understood the mechanisms of action on living organisms and the regulations evolved with our understanding.’

gold nanoparticles cross the membrane

This is the first observation to show directly how tiny gold nanoparticles can cross a lipid bilayer.

An empirical test of toxicity is that you put nanoparticles into the cells and you see the cells are dead, but you don’t understand what has happened, this is empirical. This is a legitimate tool, but it is not enough to address toxicity. Instead, one could start from the properties of nanoparticles and think about classifying nano-objects based on their physical or chemical properties by trying to predict the effect of a given nanoparticle on a cell or tissue beforehand.

I understand, it may look too ambitious, since there are a lot of tiny details that are not considered at the moment in theoretical models or any classification. However, even if it may not be exact, it can give some guidance and it would be possible to make predictions on how nanoparticles and polymers interact with lipid membranes. For example, in this study we used theoretical modelling to suggest the size and surface properties of the nanoparticle that is able to cross the lipid membrane through a certain pathway and it was observed experimentally.’


Breakthrough In The BioMedical Industry

Polyhedral boranes, or clusters of boron atoms bound to hydrogen atoms, are transforming the biomedical industry. These manmade materials have become the basis for the creation of cancer therapies, enhanced drug delivery and new contrast agents needed for radioimaging and diagnosis. Now, a researcher at the University of Missouri has discovered an entirely new class of materials based on boranes that might have widespread potential applications, including improved diagnostic tools for cancer and other diseases as well as low-cost solar energy cells.

Mark Lee Jr., an assistant professor of chemistry in the MU College of Arts and Science, discovered the new class of hybrid nanomolecules by combining boranes with carbon and hydrogen. Boranes are chemically stable and have been tested at extreme heat of up to 900 degrees Celsius or 1,652 degrees Fahrenheit. It is the thermodynamic stability these molecules exhibit that make them non-toxic and attractive to the biomedical, personal computer and alternative energy industries.
Polyhedral boranes

Despite their stability, we discovered that boranes react with aromatic hydrocarbons at mildly elevated temperatures, replacing many of the hydrogen atoms with rings of carbon,” Lee said. “Polyhedral boranes are incredibly inert, and it is their reaction with aromatic hydrocarbons like benzene that will make them more useful.”

Lee also showed that the attached hydrocarbons communicate with the borane core. “The result is that these new materials are highly fluorescent in solution,” Lee said. “Fluorescence can be used in applications such as bio-imaging agents and organic light-emitting diodes like those in phones or television screens. Solar cells and other alternative energy sources also use fluorescence, so there are many practical uses for these new materials.
The findings have been recently published in the international journal Angewandte Chemie.


First Driverless Electric Bus Line Opened In Paris

Shuttling their way to a greener city. Paris opening its first driverless buses to the public on Monday. Fully electric and fully autonomous, the ‘EZ 10‘ transports up to 10 passengers across the Seine between two main stations. The buses use laser sensors to analyse their surroundings on the road and for now they don’t have to share it with any other vehicles.


“Fewer people come on board, its slower, its electric, it doesn’t pollute and it can be stored away more easily but it will never replace a traditional bus“, says Jose Gomes, who has been driving buses here for 26 years. He’ll oversee the smooth operation of the autonomous bus.

The shuttles come as Paris faces high pollution levels. City mayor Anna Hidalgo wants to reduce the number of cars, while authorities crack down on traffic restrictions. It may be a short 130m stretch for the buses but for Paris, it’s a big step towards promoting cleaner transport.


Stem Cells Boost Bones Repair

A recent study, affiliated with UNIST (South Korea) has developed a new method of repairing injured bone using stem cells from human bone marrow and a carbon material with photocatalytic properties, which could lead to powerful treatments for skeletal system injuries, such as fractures or periodontal disease. In the study, the research team reported that the use of human bone marrow-derived mesenchymal stem cells (hBMSCs) has been tried successfully in fracture treatment due to their potential to regenerate bone in patients who have lost large areas of bone from either disease or trauma. Recently, many attempts have been made to enhance the function of stem cells using carbon nanotubes, graphenes, and nano-oxides.

Professor Kim and Professor Suh (UNIST) examined the C₃N₄sheets. They discovered that this material absorbs red light and then emits fluorescence, which can be used to speed up bone regeneration. Professor Suh conducted a biomedical application of this material. After two days of testing, the material showed no cytotoxicity, making it useful as biomaterials.

bone-repairUpper left) Chemical bonding and physical structure of C₃N₄4 sheets. (Lower left) In a liquid state, red light is transmitted at a maximum of 450nm and emitted at a wavelength of 635 nm. (Right) After 4 weeks of loading C₃N₄4 sheets into the skull-damaged mice, the skull was regenerated by more than 90%.

This research has opened up the possibility of developing a new medicine that effectively treats skeletal injuries, such as fractures and osteoporosis,” said Professor Young-Kyo Seo. “It will be a very useful tool for making artificial joints and teeth with the use of 3D printing. This is an important milestone in the analysis of biomechanical functions needed for the development of biomaterials, including adjuvants for hard tissues such as damaged bones and teeth.”

This research has been jointly conducted by Professor Youngkyo Seo of Life Sciences and Dr. Jitendra N. Tiwari of Chemistry in collaboration with Professor Kwang S. Kim of Natural Science, Professor Pann-Ghill Suh of Life Sciences, and seven other researchers from UNIST.  The results of the study has been published in the January issue of ACS Nano journal.


Reconfigurable Materials

Metamaterialsmaterials whose function is determined by structure, not composition — have been designed to bend light and sound, transform from soft to stiff, and even dampen seismic waves from earthquakes. But each of these functions requires a unique mechanical structure, making these materials great for specific tasks, but difficult to implement broadly. But what if a material could contain within its structure, multiple functions and easily and autonomously switch between them?

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute of Biologically Inspired Engineering at Harvard University have developed a general framework to design reconfigurable metamaterials. The design strategy is scale independent, meaning it can be applied to everything from meter-scale architectures to reconfigurable nano-scale systems such as photonic crystals, waveguides and metamaterials to guide heat.

In terms of reconfigurable metamaterials, the design space is incredibly large and so the challenge is to come up with smart strategies to explore it,” said Katia Bertoldi, John L. Loeb Associate Professor of the Natural Sciences at SEAS and senior author of the paper. “Through a collaboration with designers and mathematicians, we found a way to generalize these rules and quickly generate a lot of interesting designs.”

The research is published in Nature.

Device Doubles The Energy Conversion Of Solar Cells

Scientists from Japan are utilizing nanotechnology advancements to strengthen solar cellsSolar cells convert light into electricity using a bevy of sources, including light from the sun and the burning of natural resources such as oil and natural gas. However, the cells do not convert all light to power equally, which led to scientists attempting to find ways to produce more power. The flame of a gas burner will shift from red to blue as the heat increases because higher temperatures emit light at shorter wavelengths. Higher heat offers more energy, making short wavelengths an important target in the design of solar cells. Kyoto University‘s Takashi Asano, began using optical technologies to improve energy production.

device to double the power of solar cells

Current solar cells are not good at converting visible light to electrical power. The best efficiency is only around 20 percent,” Asano said in a statement. “The problem is that heat dissipates light of all wavelengths, but a solar cell will only work in a narrow range. To solve this, we built a new nano-sized semiconductor that narrows the wavelength bandwidth to concentrate the energy.

The researchers were able to use their nanoscale semiconductor to raise the energy conversion rate to at least 40 percent. Asano and researchers at the Susumu Noda lab had previously attempted to work with higher wavelengths. “Our first device worked at high wavelengths but to narrow output for visible light required a new strategy, which is why we shifted to intrinsic silicon in this current collaboration with Osaka Gas,” Asano said. Visible wavelengths are emitted at 1000 degrees Celsius but conveniently silicon has a melting temperature of over 1,400 degrees Celsius.

This concept was utilized by the scientists, who etched silicon plates to have a large number of identical and equidistantly-spaced rods, the height, radii and spacing of which was optimized for the target bandwidth. Susumu Noda, a professor at Kyoto University, explained the benefits of the advancement: “Our technology has two important benefits. First is energy efficiency: we can convert heat into electricity much more efficiently than before. Secondly is design:  we can now create much smaller and more robust transducers, which will be beneficial in a wide range of applications.”

The study was published in Science Advances.


New Material Ten Times Stronger Than Steel, Designed From Graphene

A team of researchers at MIT has designed one of the strongest lightweight materials known, by compressing and fusing flakes of graphene, a two-dimensional form of carbon. The new material, a sponge-like configuration with a density of just 5 percent, can have a strength 10 times that of steel. In its two-dimensional form, graphene is thought to be the strongest of all known materials. But researchers until now have had a hard time translating that two-dimensional strength into useful three-dimensional materials.

The new findings show that the crucial aspect of the new 3-D forms has more to do with their unusual geometrical configuration than with the material itself, which suggests that similar strong, lightweight materials could be made from a variety of materials by creating similar geometric features.

graphene material

The team was able to compress small flakes of graphene using a combination of heat and pressure. This process produced a strong, stable structure whose form resembles that of some corals and microscopic creatures called diatoms. These shapes, which have an enormous surface area in proportion to their volume, proved to be remarkably strong. “Once we created these 3-D structures, we wanted to see what’s the limit — what’s the strongest possible material we can produce,” says Zhao Qin, research scientist at MIT. To do that, they created a variety of 3-D models and then subjected them to various tests. In computational simulations, which mimic the loading conditions in the tensile and compression tests performed in a tensile loading machine, “one of our samples has 5 percent the density of steel, but 10 times the strength,” Qin says.
The findings have been reported in the journal Science Advances.


How To Fast Manufacture NanoRobots

A team of researchers led by Biomedical Engineering Professor Sam Sia at Columbia Engineering has developed a way to manufacture microscale machines from biomaterials that can safely be implanted in the body. Working with hydrogels, which are biocompatible materials that engineers have been studying for decades, Sia has invented a new technique that stacks the soft material in layers to make devices that have three-dimensional, freely moving parts. The study, published online January 4, 2017, in Science Robotics, demonstrates a fast manufacturing method Sia calls “implantable microelectromechanical systems” (iMEMS).

By exploiting the unique mechanical properties of hydrogels, the researchers developed a “locking mechanism” for precise actuation and movement of freely moving parts, which can function as valves, manifolds, rotors, pumps, and drug delivery systems. They were able to tune the biomaterials within a wide range of mechanical and diffusive properties and to control them after implantation without a sustained power supply, such as a toxic battery. They then tested the payload delivery in a bone cancer model and found that the triggering of releases of doxorubicin from the device over 10 days showed high treatment efficacy and low toxicity, at 1/10th of the standard systemic chemotherapy dose.

implantable nanorobot

Overall, our iMEMS platform enables development of biocompatible implantable microdevices with a wide range of intricate moving components that can be wirelessly controlled on demand and solves issues of device powering and biocompatibility,” says Sia, also a member of the Data Science Institute. “We’re really excited about this because we’ve been able to connect the world of biomaterials with that of complex, elaborate medical devices.  Our platform has a large number of potential applications, including the drug delivery system demonstrated in our paper which is linked to providing tailored drug doses for precision medicine.”


Electric Motorbike Round-The-World Trip

80-day round-the-world trips aren’t new – but using an electric motorbike built from scratch by students on them certainly is. Eindhoven University of Technology (Netherlands) riders drove up to 500 kilometres a day on their self-constructed Storm Wave bike, relying entirely on battery power. Other students rode behind in a bus, with one change of driver and battery swap per day.

Storm electric motorcycleCLICK ON THE IMAGE TO ENJOY THE VIDEO

With a full pack you can ride 400 kilometres on one single charge. But during our tour we had to drive more, so we had to re-energise quickly. So we just took the empty ones out, replaced them with charged ones, and we could ride again,” says Bas Verkaik, Spokeperson for Storm Eindhoven.  Key to the Storm Wave is its unique modular system of 24 individual batteries. This helped ease navigation of difficult roads in countries like Turkmenistan and Uzbekhistan.

When we faced those bad roads we just took, for example half of the batteries out, we have a lighter motorcycle, lower centre of gravity, which makes it easier to handle,” comments Bas Verkaik. Storm Wave also contains a gearbox, unusual for an electric motorcycle, but allowing greater acceleration and efficiency at high speeds.

The misconceptions people have about electric vehicles is that either they’re slow or they don’t have enough power or they can’t drive fast or far enough. With our motorcycle it can go from zero to 100 (kilometres per hour) in under five seconds, and probably could go even faster if we changed some specs… I think it looks pretty nice. That’s also a misconception that people have, that electric vehicles have to be futuristic and they don’t like the design, but I’ve only heard good things about this motorcycle” , explains Storm Wave driver Yorick Heidema.

The 23 students returned home in November after receiving huge interest in cities they drove through. They say they’ve showed the world that long-distance electric vehicle travel isn’t just feasible, but cool too.


Nanoparticles Trigger Dormant Viruses In Lung Cells

Nanoparticles from combustion engines can activate viruses that are dormant in lung tissue cells. This is the result of a study by researchers of Helmholtz Zentrum München, a partner in the German Center for Lung Research (DZL), which has now been published in the journal ‘Particle and Fibre Toxicology‘.

To evade the immune system, some viruses hide in cells of their host and persist there. In medical terminology, this state is referred to as a latent infection. If the immune system becomes weakened or if certain conditions change, the viruses become active again, begin to proliferate and destroy the host cell. A team of scientists led by Dr. Tobias Stöger of the Institute of Lung Biology and Prof. Dr. Heiko Adler, deputy head of the research unit Lung Repair and Regeneration at Helmholtz Zentrum München, now report that nanoparticles can also trigger this process.

car engine nanoparticles

From previous model studies we already knew that the inhalation of nanoparticles has an inflammatory effect and alters the immune system,” said study leader Stöger. Together with his colleagues Heiko Adler and Prof. Dr. Philippe Schmitt-Kopplin, he showed that “an exposure to nanoparticles can reactivate latent herpes viruses in the lung.