Articles from July 2013

NanoWires Boost Bone Cells Growth By 80%

Researchers from The Ohio State University have found that bone cells grow and reproduce faster on a textured surface than they do on a smooth one—and they grow best when they can cling to a microscopic shag carpet made of tiny metal oxide wires. In tests, the wires boosted cell growth by nearly 80 percent compared to other surfaces, which suggests that the coating would help healthy bone form a strong bond with an implant faster.
Broken bones and joint replacements may someday heal faster, thanks to this unusual coating for medical implants under development. In tests, the wires boosted cell growth by nearly 80 percent compared to other surfaces, which suggests that the coating would help healthy bone form a strong bond with an implant faster.

Cells show signs of healthy growth in this transmission electron microscope image, taken 15 hours after the cells were placed on a titanium surface coated with a carpet of tiny nanowires. In the inset (upper left), filaments can be seen reaching out from cells to the surface, which indicates a strong connection.

What’s really exciting about this technique is that we don’t have to carve the nanowires from a solid piece of metal or alloy. We can grow them from scratch, by exploiting the physics and chemistry of the materials,” said Sheikh Akbar, professor of materials science and engineering at Ohio State. “That’s why we call our process ‘nanostructures by material design.’”

Finally, the engineers have developed an affordable technique for creating the wires, which they describe in a paper issue of the journal Ceramics International.

Novel Solar Cell Twice More Efficient

Nearly doubling the efficiency of a breakthrough photovoltaic cell they created last year, UCLA researchers have developed a two-layer, see-through solar film that could be placed on windows, sunroofs, smartphone displays and other surfaces to harvest energy from the sun. Researchers led by Yang Yang, the Carol and Lawrence E. Tannas, Jr., Professor of Engineering at the UCLA Henry Samueli School of Engineering and Applied Science, said the new cells could serve as a power-generating layer on windows and smartphone displays without compromising users’ ability to see through the surface. The cells can be produced so that they appear light gray, green or brown, and so can blend with the color and design features of buildings and surfaces.
The new device is composed of two thin polymer solar cells that collect sunlight and convert it to power. It’s more efficient than previous devices, the researchers say, because its two cells absorb more light than single-layer solar devices, because it uses light from a wider portion of the solar spectrum, and because it incorporates a layer of novel materials between the two cells to reduce energy loss.
transparent SolarCell
Using two solar cells with the new interfacial materials in between produces close to two times the energy we originally observed,” said Yang, who is also director of the Nano Renewable Energy Center at the California NanoSystems Institute at UCLA. “We anticipate this device will offer new directions for solar cells, including the creation of solar windows on homes and office buildings.”


Solar Cells at the Price of Pocketbooks

Engineers at the University of California, Berkeley, have developed an inexpensive new way to grow thin films of a material prized in the semiconductor and photovoltaic industries, an achievement that could bring high-end solar cells within reach of consumer pocketbooks.

solar-satelliteUC Berkeley engineers could help make high-end solar cells, currently used in satellites and other space and military applications, affordable for consumer markets.
Performance is everything in the solar cell industry, but performance at a reasonable cost is key,” said Javey, who is also a faculty scientist at the Lawrence Berkeley National Laboratory. “The techniques we are reporting here should be a game-changer for III-V solar cells, as well as for LEDs.”

Top of the line photovoltaics are made from a class of material known as III-V (pronounced “three-five”) compounds, known for their superior efficiency at converting light into power. However, the complex manufacturing requirements for III-V materials make them up to 10 times more expensive than silicon, limiting their use to military applications and NASA satellites, the researchers said.

The work, led by Ali Javey, UC Berkeley associate professor of electrical engineering and computer sciences, is described in a paper published in Scientific Reports, Nature’s open access journal.

Molecular Switch Turns Blood Clotting On, Off

Using gold nanoparticles, MIT researchers have devised a new way to turn blood clotting on and off. The particles, which are controlled by infrared laser light, could help doctors control blood clotting in patients undergoing surgery, or promote wound healing. Currently, the only way doctors can manage blood clotting is by administering blood thinners such as heparin. This reduces clotting, but there is no way to counteract the effects of heparin and other blood thinners.
blood cells
A colorized electron micrograph of red blood cells with gold nanorods (yellow dots) on their surfaces. The blue represents a fixing polymer

It’s like you have a light bulb, and you can turn it on with the switch just fine, but you can’t turn it off. You have to wait for it to burn out,” says Kimberly Hamad-Schifferli, a technical staff member at MIT Lincoln Laboratory and senior author of a paper describing the new particles, which can turn blood clotting off and then restore it when necessary.


How To Detect Cancer In A Single Molecule

Just months after setting a record for detecting the smallest single virus in solution, researchers at the Polytechnic Institute of New York University (NYU-Poly) have announced a new breakthrough: They used a nano-enhanced version of their patented microcavity biosensor to detect a single cancer marker protein, which is one-sixth the size of the smallest virus, and even smaller molecules below the mass of all known markers. This achievement shatters the previous record, setting a new benchmark for the most sensitive limit of detection, and may significantly advance early disease diagnostics. Unlike current technology, which attaches a fluorescent molecule, or label, to the antigen to allow it to be seen, the new process detects the antigen without an interfering label.

breast-cancer-cell Label-Free Cancer Marker Detection

The implications of single protein detection are significant and may lay the foundation for improved medical therapeutics. Among other advances, Arnold and his colleagues posit that the ability to follow a signal in real time—to actually witness the detection of a single disease marker protein and track its movement—may yield new understanding of how proteins attach to antibodies.

Stephen Arnold, university professor of applied physics and member of the Othmer-Jacobs Department of Chemical and Biomolecular Engineering, published details of the achievement in Nano Letters, a publication of the American Chemical Society.


Multicolored Solar Panels

Until now, designers of buildings have no choice but to use black or bluish-gray colored solar panels. With the help of thin-film technologies, researchers have now been able to turn solar cells into colorful creations.
Covering a roof or a façade with standard solar cells to generate electricity will change a building’s original appearance – and not always for the better. At present only dark solar panels are widely available on the market.
But things are changing. The physicist Kevin Füchsel, project manager at the Fraunhofer Institute for Applied Optics and Precision Engineering IOF in Jena.- Germany – has been focusing for the last four years on nanostructured solar cells suitable for mass production as part of a junior research group funded by Germany’s Federal Ministry for Education and Research (BMBF). Together with a Fraunhofer team and scientists from the Friedrich-Schiller University in Jena, the group of optics specialists is looking for cost-effective techniques and manufacturing processes to increase both the efficiency of solar panels and the design flexibility they give architects and designers.
colorful solar panels

Not enough work has been done so far on combining photovoltaics and design elements to really do the term ‘customized photovoltaics’ justice,” says Kevin Füchsel. project manager at the Fraunhofer Institute for Applied Optics and Precision Engineering IOF in Jena.


Green Hydrogen Fuel For Electric Car

A protein found in the membranes of ancient microorganisms that live in desert salt flats could offer a new way of using sunlight to generate environmentally friendly hydrogen fuel, according to a new study by researchers at the U.S. Department of Energy’s Argonne National Laboratory. Argonne nanoscientist Elena Rozhkova and her colleagues combined a pigment called bacteriorhodopsin with semiconducting nanoparticles to create a system that uses light to spark a catalytic process that creates hydrogen fuel.

h-mobil car
Scientists have been aware of the potential of titanium dioxide nanoparticles for light-based reactions since the early 1970s, when Japanese researchers discovered that a titanium dioxide electrode exposed to bright ultraviolet light could split water molecules in a phenomenon that came to be known as the Honda-Fujishima effect.
Titanium dioxide alone reacts with ultraviolet light, but not with visible light, so we used biological photoreactive molecules as a building block to create a hybrid system that could use visible light efficiently,” Rozhkova said.


How To Fabricate Nano-Objects From Your Desktop

A new low-cost, high-resolution tool is primed to revolutionize how nanotechnology is produced from the desktop, according to a new study by Northwestern University researchers. Currently, most nanofabrication is done in multibillion-dollar centralized facilities called foundries. This is similar to printing documents in centralized printing shops. Consider, however, how the desktop printer revolutionized the transfer of information by allowing individuals to inexpensively print documents as needed. This paradigm shift is why there has been community-wide ambition in the field of nanoscience to create a desktop nanofabrication tool.

sand grain size car sand grain size car

With this breakthrough, we can construct very high-quality materials and devices, such as processing semiconductors over large areas, and we can do it with an instrument slightly larger than a printer,” said Chad A. Mirkin, senior author of the study and a world-renowned pioneer in the field of nanoscience.

The study has been published in the journal Nature Communications.

Thinnest Light Absorber On Record Boosts Solar Cells Efficiency

Stanford University scientists have created the thinnest, most efficient absorber of visible light on record. The nanosize structure, thousands of times thinner than an ordinary sheet of paper, could lower the cost and improve the efficiency of solar cells, according to the scientists. Thinner solar cells require less material and therefore cost less. The challenge for researchers is to reduce the thickness of the cell without compromising its ability to absorb and convert sunlight into clean energy.

These four wafers contain the thinnest light-absorber ever built. The absorber layer consists of billions of gold nanodots. Each round dot has a volume equivalent to a flat particle of gold 1.6-nanometers thick.
Achieving complete absorption of visible light with a minimal amount of material is highly desirable for many applications, including solar energy conversion to fuel and electricity,” said Stacey Bent, a professor of chemical engineering at Stanford and a member of the research team. “Our results show that it is possible for an extremely thin layer of material to absorb almost 100 percent of incident light of a specific wavelength.

Results are published in the current online edition of the journal Nano Letters.

Cubesats, Super Powerful Tiny Satellites

A NASA engineer has achieved a milestone in his quest to advance an emerging super-black nanotechnology that promises to make spacecraft instruments more sensitive without enlarging their size.
A team led by John Hagopian, an optics engineer at NASA’s Goddard Space Flight Center in Greenbelt, Md., has demonstrated that it can grow a uniform layer of carbon nanotubes through the use of another emerging technology called atomic layer deposition or ALD. The marriage of the two technologies now means that NASA can grow nanotubes on three-dimensional components, such as complex baffles and tubes commonly used in optical instruments.

The significance of this is that we have new tools that can make NASA instruments more sensitive without making our telescopes bigger and bigger,” Hagopian said. “This demonstrates the power of nanoscale technology, which is particularly applicable to a new class of less-expensive tiny satellites called Cubesats that NASA is developing to reduce the cost of space missions.

Life Extension

Researchers at the University of Basel – Switzerland – have successfully developed artificial organelles that are able to support the reduction of toxic oxygen compounds. This opens up new ways in the development of novel drugs that can influence pathological states directly inside the cell. Free oxygen radicals are produced either as metabolic byproduct, or through environmental influences such as UV-rays and smog. Is the concentration of free radicals inside the organism elevated to the point where the antioxidant defense mechanism is overwhelmed, the result can be oxidative stress, which is associated with numerous diseases such as cancer of arthritis. The aggressive molecules are normally controlled by endogenous antioxidants. Within this process, organelles located inside the cell, so-called peroxisomes, play an important part, since they assist in regulating the concentration of free oxygen radicals.

artificial peroxisome
Prof. Cornelia Palivan and her research group at the University of Basel have successfully produced artificial peroxisomes that mimic the natural organelle. The researchers developed a cell organelle based on polymeric nanocapsules.

The results have been published in the Journal «Nano Letters».

RNA Molecules Deliver Drugs To Silence Cancerous Genes

Researchers at Sanford-Burnham Medical Research Institute have developed nanoparticles that appear to solve a big challenge in delivering the RNA molecules, called small interfering RNA, or siRNA, to the cells where they are needed. By synthesizing a nanoparticle that releases its siRNA cargo only after it enters targeted cells, Dr. Tariq M. Rana and colleagues showed in mice that they could deliver drugs that silenced the genes they wanted.


Our study describes a strategy to reduce toxic effects of nanoparticles, and deliver a cargo to its target,” said Dr. Rana, whose paper, “In Vivo Delivery of RNAi by Reducible Interfering Nanoparticles (iNOPs),” also included contributions from researchers at the University of Massachusetts Medical School and the University of California at San Diego. “We’ve found a way to release the siRNA compounds, so it can be more effective where it’s needed,” Dr. Rana said.