READE SuperSite Search

Type your search query in the input boxes to the right and hit the 'Enter' key.

Product Search


Services Search


Nanotechnology RSS News Feeds


Nano 'pin art': NIST arrays are step toward mass production of nanowires
Friday, 30 July 2010 16:31
NIST researchers grow nanowires made of semiconductors -- gallium nitride alloys -- by depositing atoms layer-by-layer on a silicon crystal under high vacuum. NIST has the unusual capability to produce these nanowires without using metal catalysts, thereby enhancing luminescence and reducing defects. NIST nanowires also have excellent mechanical quality factors.

 
Nanomaterial in novel home-air treatment counters hazards from toxic drywall
Friday, 30 July 2010 11:38
A nanomaterial originally developed to fight toxic waste is now helping reduce debilitating fumes in homes with corrosive drywall.

 
Graphene shows strange new behavior better suited for electronic devices
Thursday, 29 July 2010 15:00
Regarded as a possible replacement for silicon-based semiconductors, graphene, a sheet of pure carbon, has been discovered to have an uncommon and astonishing property that might make it better matched for future electronic devices.

 
'White graphene' to the rescue: Hexagonal boron nitride sheets may help graphene supplant silicon
Thursday, 29 July 2010 13:29
What researchers might call "white graphene" may be the perfect sidekick for the real thing as a new era unfolds in nanoscale electronics.

 
Nanotechnology for water purification
Thursday, 29 July 2010 07:20
Nanotechnology refers to a broad range of tools, techniques and applications that simply involve particles on the approximate size scale of a few to hundreds of nanometers in diameter. Particles of this size have some unique physicochemical and surface properties that lend themselves to novel uses. Indeed, advocates of nanotechnology suggest that this area of research could contribute to solutions for some of the major problems we face on the global scale such as ensuring a supply of safe drinking water for a growing population, as well as addressing issues in medicine, energy, and agriculture.

 
Nanomaterials poised for big impact in construction
Thursday, 29 July 2010 04:41
Nanomaterials are poised for widespread use in the construction industry, where they can offer significant advantages for a variety of applications ranging from making more durable concrete to self-cleaning windows. But widespread use in building materials comes with potential environmental and health risks when those materials are thrown away. Those are the conclusions of a new study published by Rice University engineering researchers this month in ACS Nano.

 
Super-sizing a cancer drug minimizes side effects
Wednesday, 28 July 2010 00:00
One of the first chemotherapy drugs given to patients diagnosed with cancer — especially lung, ovarian or breast cancer — is cisplatin, a platinum-containing compound that gums up tumor cells’ DNA. Cisplatin does a good job of killing those tumor cells, but it can also seriously damage the kidneys, which receive high doses of cisplatin because they filter the blood.

Now a team of scientists at the Harvard-MIT Division of Health Sciences and Technology (HST) has come up with a new way to package cisplatin into nanoparticles that are too big to enter the kidneys. The new compound could spare patients the usual side effects and allow doctors to administer higher doses of the drug, says Shiladitya Sengupta, leader of the research team.

“We could give so much more cisplatin than is now possible,” says Sengupta, an assistant professor of HST. “You could wipe out the tumor by carpet-bombing it.”

Tumors in mice treated with the new cisplatin nanoparticle shrank to half the size of those treated with traditional cisplatin, with minimal side effects. The findings were reported in the Proceedings of the National Academy of Sciences in June.

Beads on a string

Doctors began using cisplatin to treat cancer in the 1970s. Early on, doctors recognized that it harmed the kidneys, and cancer researchers began looking for alternatives. In the past few decades, the FDA has approved two less-toxic derivatives of cisplatin: carboplatin and oxaliplatin. However, those drugs don’t kill tumor cells as successfully as cisplatin.

Cisplatin’s effectiveness lies in how easily it releases its platinum molecule, freeing it to cross-link DNA strands, disrupting cell division and forcing the cell to undergo suicide. Carboplatin and oxaliplatin are less effective (but less toxic) than cisplatin because they hold on to their platinum atoms more tightly.

Sengupta and his colleagues took a new approach to making cisplatin safer: stringing cisplatin molecules together into a nanoparticle that is too large to get into the kidneys. (It has been shown that the kidneys cannot absorb particles larger than five nanometers — about 1/10,000th the diameter of a human hair).

His team designed a polymer that binds to cisplatin, arranging the molecules like beads on a string. The string then winds itself into a nanoparticle about 100 nanometers long — much too large to fit into the kidneys. However, the particles can still reach tumor cells because tumors are surrounded by “leaky” blood vessels, which have 500-nanometer pores.

Their first nanoparticle proved less effective than cisplatin, so they tweaked the polymer to make it hold a little less tightly to platinum, and ended up with a molecule with a tumor-killing power similar to cisplatin’s. However, because its side effects are minimal, the nanoparticle can be delivered in higher doses.

Daniela Dinulescu, an author of the paper and pathology instructor at Brigham and Women’s Hospital in Boston, showed that the nanoparticles outperformed cisplatin in mice engineered to develop ovarian cancer. The researchers also showed it to be effective against lung and breast tumor cells grown in the lab. Once the tumor cells die, the immune system clears platinum from the body.

The research was funded by the Department of Defense Breast Cancer Research Program and the National Institutes of Health.

It is difficult to develop and gain approval for new platinum-based compounds, says Nicholas Farrell, professor of inorganic chemistry at Virginia Commonwealth University, but he believes Sengupta’s new nanoparticles are promising. “If successful, the approach promises to maintain the status of cisplatin as one of the most useful drugs available to the clinician,” says Farrell.

The MIT researchers are now working on new variants of the nanoparticles that would be easier to manufacture. They are also making plans to test the nanoparticles in clinical trials, which Sengupta hopes will get underway within the next two years. The polymer used for the nanoparticle backbone is similar to malic acid, a natural product of cellular metabolism, so Sengupta is optimistic that it will prove safe in humans.

 
A new use for gold
Friday, 11 June 2010 00:00
Gold nanoparticles — tiny spheres of gold just a few billionths of a meter in diameter — have become useful tools in modern medicine. They’ve been incorporated into miniature drug-delivery systems to control blood clotting, and they’re also the main components of a device, now in clinical trials, that is designed to burn away malignant tumors.

However, one property of these particles stands in the way of many nanotechnological developments: They‘re sticky. Gold nanoparticles can be engineered to attract specific biomolecules, but they also stick to many other unintended particles — often making them inefficient at their designated task. 

MIT researchers have found a way to turn this drawback into an advantage. In a paper recently published in American Chemical Society Nano, Associate Professor Kimberly Hamad-Schifferli of the Departments of Biological Engineering and Mechanical Engineering and postdoc Sunho Park PhD ’09 of the Department of Mechanical Engineering reported that they could exploit nanoparticles’ stickiness to double the amount of protein produced during in vitro translation — an important tool that biologists use to safely produce a large quantity of protein for study outside of a living cell. 

During translation, groups of biomolecules come together to produce proteins from molecular templates called mRNA. In vitro translation harnesses these same biological components in a test tube (as opposed to in vivo translation, which occurs in live cells), and a man-made mRNA can be added to guarantee the production of a desired protein. For example, if a researcher wanted to study a protein that a cell would not naturally produce, or a mutated protein that would be harmful to the cell in vivo, he might use in vitro translation to create large quantities of that protein for observation and testing. But there’s a downside to in vitro translation: It is not as efficient as it could be. “You might get some protein one day, and none for the next two,” explains Hamad-Schifferli.

With funding from the Institute of Biomedical Imaging and Bioengineering, Hamad-Schifferli and her co-workers initially set out to design a system that would prevent translation. This process, known as translation inhibition, can stop the production of harmful proteins or help a researcher determine protein function by observing cell behavior when the protein has been removed. To accomplish this, Hamad-Schifferli attached DNA to gold nanoparticles, expecting that the large nanoparticle-DNA (NP-DNA) aggregates would block translation.

She was discouraged, however, to find that the NP-DNA did not decrease protein production as expected. In fact, she had some unsettling data suggesting that instead of inhibiting translation, the NP-DNA were boosting it. “That’s when we put on our engineering caps,” recalls Hamad-Schifferli. 

It turns out that the sticky nanoparticles bring the biomolecules needed for translation into close proximity, which helps speed the translation process. Additionally, the DNA part of the NP-DNA complex is designed to bind to a specific mRNA molecule, which will be translated into a specific protein. The binding must be tight enough to hold the mRNA in place for translation, but loose enough that the mRNA can also attach to the other molecules necessary for the process. Because the designed DNA molecule has a specific mRNA partner, that mRNA in a solution of many similar molecules can be enhanced without having to be isolated.

In addition to enhancing in vitro translation, Hamad-Schifferli’s NP-DNA complexes may have other applications. According to Ming Zheng, a research chemist with the National Institute of Standards and Technology, they could be combined with carbon nanotubes — tiny, hollow cylinders that are incredibly strong for their size. They may ultimately be the cornerstone of transport systems that ferry drugs into cells or between cells. The stickiness of the NP-DNA might enhance the speed and accuracy of such a drug-delivery system.  

Although Hamad-Schifferli is confident that her discovery will make in vitro translation more reliable and efficient, she is not done. She hopes to tinker with her system to further enhance protein production in vitro, and see if the system can be applied to enhance translation in live cells. To help reach these goals, she must design and conduct experiments to determine which molecules are involved in the enhancement process, and how they interact. “The upside is that we’ve been lucky,” Hamad-Schifferli says, reflecting on her discovery. “The downside is that it will be difficult to tease out exactly how the system works.” 

 
Obama intends to nominate Suresh as next NSF director
Thursday, 03 June 2010 17:00
U.S. President Barack Obama announced Thursday that he intends to nominate Subra Suresh, dean of the MIT School of Engineering, to serve as the next director of the National Science Foundation. If confirmed by the U.S. Senate, Suresh, the Vannevar Bush Professor of Engineering at MIT, would be appointed to a six-year term as director.

“Through his invigorating leadership, Dean Suresh has led MIT's School of Engineering while pursuing his own remarkable research portfolio at the intersection of the life sciences and engineering,” said MIT Provost L. Rafael Reif. “In keeping with MIT's long tradition of national service, he will bring this same breadth of knowledge and vision to the National Science Foundation.”

The White House made its announcement about the president’s intention to nominate Suresh in a statement that also included news of the president’s intention to nominate Maura Connelly to be U.S. ambassador to Lebanon and Daniel B. Smith to be U.S. ambassador to Greece. “I am proud that such experienced and committed individuals have agreed to take on these important roles in my administration. I look forward to working with them in the coming months and years,” Obama said.

The NSF is a federal government agency that supports fundamental research and education in all the non-medical fields of science and engineering. With an annual budget of nearly $7 billion, the NSF funds approximately 20 percent of all federally supported basic research conducted by U.S. colleges and universities.

Trained as a mechanical engineer, Suresh has made dramatic contributions to a range of fields in engineering and science. He has expanded his research interests to encompass materials, nanotechnology and the life sciences, and has most recently done extensive work on the red blood cell and its nanobiomechanical properties as they influence a variety of diseases. Suresh has made significant advances and created a range of new experimental methodologies to unravel the inner workings of such diseases as malaria.

Suresh is the author of more than 220 research articles in international journals, coeditor of five books, and coinventor on more than 12 U.S. and international patents. More than 100 students, postdoctoral associates, and research scientists have trained in his research group, and many now occupy prominent positions in academia, industry and governments around the world. He is author or coauthor of several books, including Fatigue of Materials and Thin Film Materials — widely used in materials science and engineering.

Suresh has held joint faculty appointments in four MIT departments, and has served as dean of the School of Engineering since July 2007. During his tenure, the school has seen unprecedented growth in the diversity of its faculty. Approximately 45 new faculty members have joined the school since he became dean, and in 2009, for the first time in its history, the school hired more new women faculty than men.

“Subra is an outstanding engineering scientist,” said Marc Kastner, dean of MIT’s School of Science. “He has a very broad perspective on why science is important for its own sake — as well as for its applications.”

Suresh received his bachelor of technology degree from the Indian Institute of Technology, Madras, in 1977, his MS from Iowa State University in 1979 and his ScD from MIT in 1981. Following postdoctoral research from 1981 to 1983 at the University of California at Berkeley and the Lawrence Berkeley National Laboratory, he joined Brown University as an assistant professor of engineering in December 1983; he was promoted to full professor in July 1989. He joined MIT in 1993 as the R. P. Simmons Professor of Materials Science and Engineering.

Suresh is the recipient of the 2007 European Materials Medal, the highest honor conferred by the Federation of European Materials Societies, and the 2006 Acta Materialia Gold Medal. In 2006, Technology Review magazine selected Suresh's work on nanobiomechanics as one of the top 10 emerging technologies that “will have a significant impact on business, medicine or culture.” He has been elected to the U.S. National Academy of Engineering, the American Academy of Arts and Sciences, the Indian National Academy of Engineering, and the German National Academy of Sciences, the Indian Academy of Sciences and the Spanish Royal Academy of Sciences.


 
Liquid-solid interactions, as never before seen
Monday, 26 April 2010 00:00
Wettability — the degree to which a liquid either spreads out over a surface or forms into droplets — is crucial to a wide variety of processes. It influences, for example, how easily a car’s windshield fogs up, and also affects the functioning of advanced batteries and fuel-cell systems.

Until now, the only way to quantify this important characteristic of a material’s surface has been to measure the shapes of the droplets that form on it, and this method has very limited resolution. But a team of MIT researchers has found a way to obtain images that improves the resolution of such measurements by a factor of 10,000 or more, allowing for unprecedented precision in determining the details of the interactions between liquids and solid surfaces. In addition, the new method can be used to study curved, textured or complex solid surfaces, something that could not be done previously.

“This is something that was unthinkable before,” says Francesco Stellacci, the Paul M. Cook Career Development Associate Professor of Materials Science and Engineering at MIT, leader of the team that developed the new method. “It allows us to make a map of the wetting,” that is, a detailed view of exactly how the liquid interacts with the surface down to the level of individual molecules or atoms, as opposed to just the average interaction of the whole droplet.

The new method is described in a paper appearing on April 25 in the journal Nature Nanotechnology. The lead author is postdoctoral fellow Kislon Voïtchovsky, and the paper is coauthored by Stellacci and others at MIT, in England, and in Italy. Stellacci explains that the ability to get such detailed images is important for the study of such processes as catalysis, corrosion and the internal functioning of batteries and fuel cells, and many biological processes such as interactions between proteins.

For example, Voïtchovsky says, in biological research, “you may have a very inhomogeneous sample, with all sorts of reactions going on all over the place. Now we can identify certain specific areas that trigger a reaction.”

The method, developed with support from the Swiss National Science Foundation and the Packard Foundation, works by changing the programming that controls an Atomic Force Microscope (AFM). This device uses a sharp point mounted on a vibrating cantilever, which scans the surface of a sample and reacts to topology and the properties of the sample to provide highly detailed images. Stellacci and his team have varied a key imaging parameter: They cause the point to vibrate only a few nanometers (as opposed to tens to hundred of nanometers, which is typical).

“By doing so, you actually improve the resolution of the AFM,” Stellacci explains. The resulting resolution, fine enough to map the positions of individual atoms or molecules, is “unmatched before with commercial instruments,” he says. Such resolution had been achievable before with very expensive specialized AFMs, of which only a few exist in the world, but can now be equaled by the much more common commercial models, of which there are thousands. Stellacci and his colleagues think the improved resolution results from the way the vibrating tip causes the water to repeatedly push against the surface and dissipate its energy there, but this explanation remains to be tested and confirmed by other researchers.

With their demonstration of both a 10,000-fold improvement in resolution for the specific function of measuring the wetting of surfaces and a 20-fold improvement in overall resolution of the lower-cost AFM, Stellacci says it’s not clear which of these applications will end up having more impact.

Arvind Raman, a professor and university faculty scholar in mechanical engineering at Purdue University, agrees that these advances have significant potential. The method demonstrated by this team, which Raman was not involved in, “can routinely achieve atomic resolution on hard surfaces even with commercial AFM systems, and it provides great physical insight into the optimum conditions under which this can be achieved, both of which are very significant achievements,” he says. “I really think many in the AFM field will jump on this and try to use the technique.”

Raman adds that while the team’s interpretation of why the method works as it does offers “one possible mechanism behind the image formation, other plausible mechanisms also exist and will need to be studied in the future to confirm the finding.”

 
<< Start < Prev 1 2 3 4 5 6 7 8 9 10 Next > End >>

Page 5 of 283

Translate

English French German Italian Portuguese Spanish

Text Resize

Request a quote from READE Advanced Materials
READE Science and Technology Bookstore

Join Us On...

Join us on The Nanomaterials Society

Follow Us On...

Follow our updates on Twitter