Articles from September 2013



New Record Of Solar Hydrogen Efficiency

A research team of Ulsan National Institute of Science and Technology (UNIST), South Korea, developed a “wormlike” hematite photoanode that can convert sunlight and water to clean hydrogen energy with a record-breaking high efficiency of 5.3%. The previous record of solar hydrogen efficiency among stable oxide semiconductor photoanodes was 4.2% owned by the research group of Prof. Michael Graetzel at the Ecole Polytechnique de Lausanne (EPFL), Switzerland.

Solar water splitting is a renewable and sustainable energy production method because it can utilize sunlight, the most abundant energy source on earth, and water, the most abundant natural resource on earth. At the moment, low solar-to-hydrogen conversion efficiency is the most serious hurdle to overcome in the commercialization of this technology. The key to the solar water splitting technology is the semiconductor photocatalysts that absorb sunlight and split water to hydrogen and oxygen using the absorbed solar energy. Hematite, an iron oxide (the rust of iron, Fe2O3) absorbs an ample amount of sunlight. It has also excellent stability in water, a low price, and environmentally benign characteristics. Prof. Jae Sung Lee of UNIST led the joint research with Prof. Kazunari Domen’s group at the University of Tokyo, Japan, developing new anode material which has outstanding hydrogen production efficiency.

Pt-doped nanostructureThe efficiency of 10% is needed for practical application of solar water splitting technology. There is still long way to reach that level. Yet, our work has made an important milestone by exceeding 5% level, which has been a psychological barrier in this field,” said Prof. Lee. “It has also demonstrated that the carefully designed fabrication and modification strategies are effective to obtain highly efficient photocatalysts and hopefully could lead to our final goal of 10% solar-to-hydrogen efficiency in a near future.”

This research was published in Scientific Reports, a science journal published by the Nature Publishing Group.
Source: https://www.unist.ac.kr/
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http://www.nature.com/

How To Protect Vaccine And Provoke Immune Response

Many viruses and bacteria infect humans through mucosal surfaces, such as those in the lungs, gastrointestinal tract and reproductive tract. To help fight these pathogens, scientists are working on vaccines that can establish a front line of defense at mucosal surfaces. Vaccines can be delivered to the lungs via an aerosol spray, but the lungs often clear away the vaccine before it can provoke an immune response. To overcome that, MIT engineers have developed a new type of nanoparticle that protects the vaccine long enough to generate a strong immune response — not only in the lungs, but also in mucosal surfaces far from the vaccination site, such as the gastrointestinal and reproductive tracts.
Nanoparticle protects vaccine
This is a good example of a project where the same technology can be applied in cancer and in infectious disease. It’s a platform technology to deliver a vaccine of interest,” says Irvine, who is a member of MIT’s Koch Institute for Integrative Cancer Research and the Ragon Institute of Massachusetts General Hospital, MIT and Harvard University.

Irvine and colleagues describe the nanoparticle vaccine in the journal Science Translational Medicine.
Source: http://web.mit.edu/

DNA Nanocomputer From Graphene

Stanford chemical engineering professor Zhenan Bao have imagined a new generation of computer chips based not on silicon, but on graphene and DNA, the blueprint for life. Graphene, a sheet of carbon atoms arrayed in a honeycomb pattern, could be a better semiconductor than silicon.
graphene_DNA

To the right is a honeycomb of graphene atoms. To the left is a double strand of DNA. The white spheres represent copper ions integral to the chemical assembly process. The fire represents the heat that is an essential ingredient in the technique

Bao and other researchers believe that ribbons of graphene, laid side-by-side, could create semiconductor circuits. Given the material’s tiny dimensions and favorable electrical properties, graphene nano ribbons could create very fast chips that run on very low power, she said. “However, as one might imagine, making something that is only one atom thick and 20 to 50 atoms wide is a significant challenge,” said co-researcher Sokolov. To handle this challenge, the Stanford team came up with the idea of using DNA as an assembly mechanism. Chemically, DNA molecules contain carbon atoms, the material that forms graphene. “Our DNA-based fabrication method is highly scalable, offers high resolution and low manufacturing cost,” said co-researcher Yap. “All these advantages make the method very attractive for industrial adoption.”
The findings have been pusblished in the journal Nature Communications.
Source: http://engineering.stanford.edu/

New Step Towards Massive Use Of Fuel Cells

Ulsan National Institute of Science and Technology (UNIST) -Korea -, Korea Institute of Energy Research (KIER), and Brookhaven National Laboratory, have discovered a new family of non-precious metal catalysts. These catalysts exhibit better performance than platinum in oxygen-reduction reaction (ORR) only with 10% of the production cost of a platinum catalyst.
The finding, described in Nature‘s Scientific Reports, provides an important step towards circumventing the biggest obstacle to widespread- commercialization of fuel cell technology.Fuel cells have various advantages compared to internal combustion engines or batteries, due to their high energy conversion efficiency and environmentally benign and quiet operation conditions. However, the high cost and instability of platinum catalysts for oxygen reduction reaction at the cathode have critically impeded the extensive application of polymer electrolyte fuel cells.

hydrogen-electric car

Currently the world is striving to look for another energy source for increased energy demand and environmental issue,” said Prof. Joo from UNIST. “The novel material developed by the UNIST research team would be a solution to commercialize the eco-friendly and cost-effective fuel cells.”

Our synthetic strategy for the non-precious metal catalysts included a multitude of advantages that would be favorable to PEFC applications” said Prof. Joo. “First, our synthetic method is amenable to simple and mild experimental conditions. Second, the synthesis of the M-OMPC catalysts could be readily scaled up to a few tens of grams in a single batch. Third, well-developed, hierarchical micro-mesoporosity would be advantageous for efficient transport of fuels and by-products. Finally, the M-OMPC catalysts showed very high surface areas, which could significantly increase the density of the catalytically active sites accessible to reactants.”

Source: http://www.unist.ac.kr/

SMILE!

A brighter, better, longer-lasting dental implant may soon be on its way to your dentist’s office. Dental implants are posts, usually made of titanium, that are surgically placed into the jawbone and topped with artificial teeth. More than dentures or bridges, implants mimic the look and feel of natural teeth. While most dental implants are successful, a small percentage fail and either fall out or must be removed. A scientist at Michigan Technological University wants to lower that rate to zero using nanotechnology.
smiling-girl
“Dental implants can greatly improve the lives of people who need them,” said Tolou Shokuhfar, an assistant professor of mechanical engineering. “But there are two main issues that concern dentists: infection and separation from the bone.

The mouth is a dirty place, so bacterial infections are a risk after implant surgery, and sometimes bone fails to heal securely around the device. Because jawbones are somewhat thin and delicate, replacing a failed implant can be difficult, not to mention expensive. Generally, dentists charge between $2,000 and $4,000 to install a single implant, and the procedure is rarely covered by insurance. Enter a nano-material that can battle infection, improve healing, and help dental implants last a lifetime: titanium dioxide nanotubes.

Source: http://www.eurekalert.org/
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http://www.mtu.edu/

Fingertip Potential to Boost Touchpad Technology

Our sense of touch is clearly more acute than many realize. A new study from the KTH Royal Institute of Technology – Sweden – demystifies the “unknown sense” with first-ever measurements of human tactile perception. People can detect nano-scale wrinkles while running their fingers upon a seemingly smooth surface. The findings could lead such advances as touch screens for the visually impaired and other products, says one of the researchers from KTH. This is the first time that scientists have quantified how people feel, in terms of a physical property. One of the authors, Mark Rutland, Professor of Surface Chemistry, says that the human finger can discriminate between surfaces patterned with ridges as small as 13 nanometres in amplitude and non-patterned surfaces.

Windows-8-All-in-One-a
This means that, if your finger was the size of the Earth, you could feel the difference between houses from cars,” Rutland says. “That is one of the most enjoyable aspects of this research. We discovered that a human being can feel a bump corresponding to the size of a very large molecule.”

Source: http://www.kth.se/

Smart Windows Tune Sunlight And Heat

Researchers at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have designed a new material to make smart windows even smarter. The material is a thin coating of nanocrystals embedded in glass that can dynamically modify sunlight as it passes through a window. Unlike existing technologies, the coating provides selective control over visible light and heat-producing near-infrared (NIR) light, so windows can maximize both energy savings and occupant comfort in a wide range of climates.

nanocrystals of indium tin oxideNanocrystals of indium tin oxide (shown here in blue) embedded in a glassy matrix of niobium oxide (green) form a composite material that can switch between NIR-transmitting and NIR-blocking states with a small jolt of electricity. A synergistic interaction in the region where glassy matrix meets nanocrystal increases the potency of the electrochromic effect

In the US, we spend about a quarter of our total energy on lighting, heating and cooling our buildings,” says Delia Milliron, a chemist at Berkeley Lab’s Molecular Foundry who led this research. “When used as a window coating, our new material can have a major impact on building energy efficiency.”

source: http://newscenter.lbl.gov/

Inexpensive Hydrogen For Electric Car

Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have created a high-performing nanocatalyst with nanoparticles tolerant to carbon monoxide, a poisoning impurity in hydrogen derived from natural gas. The novel core-shell structure —< strong>ruthenium coated with platinum — resists damage from carbon monoxide as it drives the energetic reactions central to electric vehicle fuel cells and similar technologies. The quest to harness hydrogen as the clean-burning fuel of the future demands the perfect catalysts—nanoscale machines that enhance chemical reactions. Scientists must tweak atomic structures to achieve an optimum balance of reactivity, durability, and industrial-scale synthesis.

nanocrystals
These nanoparticles exhibit perfect atomic ordering in both the ruthenium and platinum, overcoming structural defects that previously crippled carbon monoxide-tolerant catalysts,” said study coauthor and Brookhaven Lab chemist Jia Wang. “Our highly scalable, ‘green’ synthesis method, as revealed by atomic-scale imaging techniques, opens new and exciting possibilities for catalysis and sustainability.”

The findings have been published in the online journal Nature Communications.
Source: http://www.bnl.gov/

Building A Nanoscope Like a LEGO

The world’s first low cost Atomic Force Microscope (AFM) or Nanoscope has been developed in Beijing – China – by a group of PhD students from UCL – United Kingdom -, Tsinghua University and Peking University – using Lego.

In the first event of its kind, LEGO2NANO brought together students, experienced makers and scientists to take on the challenge of building a cheap and effective AFM, a device able to probe objects only a millionth of a millimetre in size – far smaller than anything an optical microscope can observe.
Lego game AFM 2

Low-cost scientific instrumentation is not just useful in high-schools, it can be a huge enabler for hospitals and clinics in developing countries, too” notes Gabriel Aeppli, director of the London Centre for Nanotechnology at UCL, a key contributor to the event, “That’s why novel initiatives like LEGO2NANO are so important.”
Low-cost scientific instruments, using cheap consumer hardware and open-source software, are becoming increasingly popular: for example, many researchers now collect data using apps on mobile phones.
Designing these state-of-the-art and low cost technologies has become an objective of industry, academia and now also the maker community, groups of talented amateurs around the globe who like to develop DIY solutions.
It’s impressive to see the UCL students working closely with their Chinese counterparts. The event was not only interdisciplinary, it also crossed the boundary between science and maker cultures”, remarked Prof. Xiao Guo, Pro-Provost (China) of UCL.

Source: http://www.ucl.ac.uk

Smartphone Detects Single Virus

Aydogan Ozcan, a professor of electrical engineering and bioengineering at the UCLA Henry Samueli School of Engineering and Applied Science, and his team have created a portable smartphone attachment that can be used to perform sophisticated field testing to detect viruses and bacteria without the need for bulky and expensive microscopes and lab equipment. The device weighs less than half a pound.

cell-phone-vs-SEM

This cellphone-based imaging platform could be used for specific and sensitive detection of sub-wavelength objects, including bacteria and viruses and therefore could enable the practice of nanotechnology and biomedical testing in field settings and even in remote and resource-limited environments,” Ozcan said. “These results also constitute the first time that single nanoparticles and viruses have been detected using a cellphone-based, field-portable imaging system.”
Source: http://newsroom.ucla.edu/

Nano Diamonds To Fight Brain Tumor

Glioblastoma is the most common and lethal type of brain tumor. Despite treatment with surgery, radiation and chemotherapy, the median survival time for glioblastoma patients is less than one-and-a-half years. The tumors are notoriously difficult to treat, in part because chemotherapy drugs injected alone often are unable to penetrate the system of protective blood vessels that surround the brain, known as the blood–brain barrier. And those drugs that do cross the barrier do not stay concentrated in the tumor tissue long enough to be effective. Now Researchers at UCLA‘s Jonsson Comprehensive Cancer Center have developed an innovative drug-delivery system in which tiny particles called nanodiamonds are used to carry chemotherapy drugs directly into brain tumors. The new method was found to result in greater cancer-killing efficiency and fewer harmful side effects than existing treatments.
BrainTumor Nanodiamonds are carbon-based particles roughly 4 to 5 nanometers in diameter that can carry a broad range of drug compounds. And while tumor-cell proteins are able to eject most anticancer drugs that are injected into the cell before those drugs have time to work, they can’t get rid of the nanodiamonds. Thus, drug–nanodiamond combinations remain in the cells much longer without affecting the tissue surrounding the tumor
The research, published in the online journal Nanomedicine: Nanotechnology, Biology and Medicine, was a collaboration between Dean Ho of the UCLA School of Dentistry and colleagues from the Lurie Children’s Hospital of Chicago and Northwestern University‘s Feinberg School of Medicine
Source: http://newsroom.ucla.edu/

The World’s Thinnest Sheet of Glass Is Two Atoms Thick

Researchers at Cornell and Germany’s University of Ulm have created the world’s thinnest pane of glass, a step towards a nanocomputer. The glass, made of silicon and oxygen, formed accidentally when the scientists were making graphene, an atom-thick sheet of carbon, on copper-covered quartz. They believe an air leak caused the copper to react with the quartz, which is also made of silicon and oxygen, producing a glass layer with the graphene. The glass is a mere three atoms thick—the minimum thickness of silica glass—which makes it two-dimensional.

Direct Imaging of a Two-Dimensional Silica Glass on Graphene
Although this is the first time such a thin sheet of freestanding glass has been produced, the image, taken with an electron microscope, isn’t entirely new. The “pane” of glass, so impossibly thin that its individual silicon and oxygen atoms are clearly visible via electron microscopy, was identified in the lab of David A. Muller, professor of applied and engineering physics and director of the Kavli Institute at Cornell for Nanoscale Science.
The two-dimensional glass could find a use in transistors, by providing a defect-free, ultra-thin material that could improve the performance of processors in computers and smartphones.

The paper, “Direct Imaging of a Two-Dimensional Silica Glass on Graphene,” was published in Nano Letters on Jan. 23, 2012, with first authors Pinshane Huang, a Cornell graduate student, and Simon Kurash, a University of Ulm graduate student. It includes collaborators from the University of Ulm, Germany; the Max Planck institute for Solid State Research in Germany; University of Vienna; University of Helsinki; and Aalto University in Finland.

Source: http://pubs.acs.org/
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http://www.news.cornell.edu/