NanoComputer

Nanowires — microscopic fibers that can be “grown” in the lab — are a hot research topic today, with a variety of potential applications including light-emitting diodes (LEDs) and sensors. Now, a team of MIT researchers has found a way of precisely controlling the width and composition of these tiny strands as they grow, making it possible to grow complex structures that are optimally designed for particular applications.

Nanowires fabricated using the new techniques developed by Silvija Gradečak and her team can have varying widths, profiles and composition along their lengths, as illustrated here, where different colors are used to indicate compositional variations. 

Silvija Gradečak, professor of materials science and engineering at the Massachusetts  Insitute of Technology, and her team,  were able to control and vary both the size and composition of individual wires as they grew. Nanowires are grown by using “seed” particles, metal nanoparticles that determine the size and composition of the nanowire. By adjusting the amount of gases used in growing the nanowires, Gradečak was  able to control the size and composition of the seed particles and, therefore, the nanowires as they grew. “We’re able to control both of these properties simultaneously,” she says.

The results are described in a new paper authored by Silvija Gradečak and her team, published in the journal Nano Letters.
Source: http://web.mit.edu/newsoffice/2012/controlled-nanowire-growth-0222.html

The development of polymer film loaded with antibodies that can capture tumor cells shows promise as a diagnostic tool. Cancer cells that break free from a tumor and circulate through the bloodstream spread cancer to other parts of the body. But this process, called metastasis, is extremely difficult to monitor because the circulating tumor cells (CTCs) can account for as few as one in every billion blood cells.

The polymer film forms nanodots: tiny bumps that can be functionalized with antibodies to grab passing cancer cells.

Scientists tested several types of tumor cells on films with various sizes and densities of nanodots, and used a microscope to observe how well they captured the cells. The most effective film, with nanodots measuring about 230 nanometers across and containing about 8 dots per square micrometer, captured roughly 240 breast-cancer cells per square millimeter of film

Research led by scientists at the RIKEN Advanced Science Institute in Wako – Japan, in collaboration with colleagues at the University of California, Los Angeles, and the Institute of Chemistry at the Chinese Academy of Sciences, Beijing, has produced a polymer film that can capture specific CTCs1. With further development, the system could help doctors to diagnose an advancing cancer and assess the effectiveness of treatments.

One month ago a research team from Switzerland has demonstrated a new way to block the spreading of metastasis in the human body.

http://www.nanocomputer.com/?p=1241

Source: http://www.rikenresearch.riken.jp/eng/research/6850

Simply by touching a small piece of Power Felt – a promising new thermoelectric device developed by scientists, Corey Hewitt (Ph.D. graduate student)  has converted his body heat into an electrical current. Comprised of tiny carbon nanotubes locked up in flexible plastic fibers and made to feel like fabric, Power Felt uses temperature differences – room temperature versus body temperature, for instance – to create a charge. The research team  is  from Wake Forest University, North Carolina, , Center for Nanotechnology and Molecular Materials..

“We waste a lot of energy in the form of heat. For example, recapturing a car’s energy waste could help improve fuel mileage and power the radio, air conditioning or navigation system,” Hewitt says. “Generally thermoelectrics are an underdeveloped technology for harvesting energy, yet there is so much opportunity.”

Cost has prevented thermoelectrics from being used more widely in consumer products. Standard thermoelectric devices use a much more efficient compound called bismuth telluride to turn heat into power in products including mobile refrigerators and CPU coolers, but it can cost $1,000 per kilogram. Like silicon, researchers liken its affordability to demand in volume and think someday Power Felt would cost only $1 to add to a cell phone cover.

Source: http://news.wfu.edu/2012/02/22/power-felt-gives-a-charge/

Dr William Parnell’s team from the  School of Mathematics at the University of Manchester, England, have been working on the theory of invisibility cloaks which, until recently, have been merely the subject of science fiction. In recent times, however, scientists have been getting close to achieving ‘cloaking’ in a variety of contexts. The work from the team at Manchester focuses on the theory of cloaking devices which could eventually help to protect buildings and structures from vibrations and natural disasters such as earthquakes.

According to the mathematician, “This research has shown that we really do have the potential to control the direction and speed of elastic waves. This is important because we want to guide such waves in many contexts, especially in nano-applications such as in electronics for example. 

“If the theory can be scaled up to larger objects then it could be used to create cloaks to protect buildings and structures, or perhaps more realistically to protect very important specific parts of those structures.”, he added. This ‘invisibility’ could prove to be of great significance in safeguarding key structures such as nuclear power plants, electric pylons and government offices from destruction from natural or terrorist attacks.You can read old posts from nanocomputer.com, relating researches about 'invisble sounds' and objects.
http://www.nanocomputer.com/?p=1464
http://www.nanocomputer.com/?p=716
http://www.nanocomputer.com/?p=1168

Source: http://www.manchester.ac.uk/aboutus/news/display/?id=7968

A new, single-step of  fabricating microcapsules, which have potential commercial applications, in industries, including medicine, agriculture and diagnostics, have been developed by researchers at the University of Cambridge, England. The findings are published in the journal Science.
The ability to enclose materials in capsules between 10 and 100 micrometres in diameter, while accurately controlling both the capsule structure and the core contents, is a key concern in biology, chemistry, nanotechnology and materials science.

“This method provides several advantages over current methods as all of the components for the microcapsules are added at once and assemble instantaneously at room temperature,” said lead author Jing Zhang, a PhD student in Professor Abell’s research group. “A variety of ‘cargos’ can be efficiently loaded simultaneously during the formation of the microcapsules. The dynamic supramolecular interactions allow control over the porosity of the capsules and the timed release of their contents using stimuli such as light, pH and temperature.”

Source: http://www.cam.ac.uk/research/news/smart-microcapsules-in-a-single-step/

How to kill cancer cells? To be effective, the drug carrier system needs to be able to identify and reach its target, and it needs to be able to release its payload at the target at the right time, or over a longer period of time.

Xian-Zheng Zhang, the Director of the Key Laboratory of Biomedical Polymers of Ministry of Education and a professor in the Department of Chemistry at Wuhan University in China, said, ."It is of great importance to design intelligent drug carriers that can specifically respond to physiopathological signals and allow explosive release of the loaded drugs while entrapping the drugs efficiently during the process of blood circulation," 

" Zhang and his team have designed and fabricated a system that could effectively keep the drug entrapped in its carrier in the blood and normal tissues, but would allow explosive drug release under the right physiopathological stimuli – an acidic environment – once the drug carrier reaches the cancerous tissue.

Source: http://onlinelibrary.wiley.com/doi/10.1002/adfm.201102132/full.

In a paper published in Nature Communications, a team of engineers at Stanford describes how it has created tiny hollow spheres of photovoltaic nanocrystalline-silicon and harnessed physics to do for light what circular rooms do for sound. The results, say the engineers, could dramatically reduce materials usage and processing cost.

“Nanocrystalline-silicon is a great photovoltaic material. It has a high electrical efficiency and is durable in the harsh sun,” said Shanhui Fan, a professor of electrical engineering at Stanford and co-author of the paper. “Both have been challenges for other types of thin solar films.” The downfall of nanocrystalline-silicon, however, has been its relative poor absorption of light, which requires thick layering that takes a long time to manufacture. By depositing two or even three layers of nanoshells atop one another, the team teased the absorption of light  higher still. With a three-layer structure, they were able to achieve total absorption of 75% of light in certain important ranges of the solar spectrum.

Source: http://engineering.stanford.edu/news/nanoshell-whispering-galleries-improve-thin-solar-panels

 A new form of proteins discovered by researchers at The University of Texas at Austin could drastically improve treatments for cancer and other diseases. The protein formulation strategy, discovered by chemical engineering faculty members and students in the Cockrell School of Engineering, University of Texas,  is unprecedented and offers a new and universal approach to drug delivery — one that could revolutionize treatment of cancer, arthritis and infectious disease. 

“We believe this discovery of a new highly concentrated form of proteins — clusters of individual protein molecules — is a disruptive innovation that could transform how we fight diseases,” said Keith P. Johnston, a chemical engineering professor and member of the National Academy of Engineering. “It required integration of challenging contributions in fundamental science and engineering from three of our chemical engineering research groups.”

The research, led by Johnston, Chemical Engineering Professor Thomas Truskett and Assistant Professor Jennifer Maynard, was published online recently ahead of a print version to appear soon in the ACS Nano journal.

Source: http://www.utexas.edu/news/2012/02/01/nano_protein_clusters/