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What's New in Nanotechnology?

November 06, 2015

Researchers at Washington University School of Medicine in St. Louis have developed a nanotherapy that is effective in treating mice with multiple myeloma, a cancer of bone marrow immune cells. From left are first author Deepti Sood Gupta, PhD, and co-senior authors Michael H. Tomasson, MD, and Gregory M. Lanza, MD, PhD. (Image Credit: Robert Boston/Washington University in St. Louis)

Researchers at Washington University School of Medicine in St. Louis have designed a nanoparticle-based therapy that is effective in treating mice with multiple myeloma, a cancer of immune cells in the bone marrow. Targeted specifically to the malignant cells, these nanoparticles protect their therapeutic cargo from degradation in the bloodstream and greatly enhance drug delivery into the cancer cells. These are longtime hurdles in the development of this class of potential cancer drugs.

The nanoparticles carry a drug compound that blocks a protein called Myc that is active in many types of cancer, including multiple myeloma. So-called Myc inhibitors are extremely potent in a petri dish. But when injected into the blood, they degrade immediately. Consequently, the prospect that Myc inhibitors could be a viable treatment in patients has been problematic because past research in animals has shown that the compounds degrade too quickly to have any effect against cancer.

The new study is the first to show that Myc inhibitors can be effective in animals with cancer, as long as the drugs have a vehicle to protect and deliver them into cancer cells. When injected into mice with multiple myeloma, the targeted nanoparticles carrying the Myc inhibitor increased survival to 52 days compared with 29 days for mice receiving nanoparticles not carrying the drug. The researchers also pointed out that the potent Myc inhibitor showed no survival benefit when injected by itself, without the nanoparticle.

Categories : University News
October 28, 2015

Scientists announced the first observation of a dynamic vortex Mott transition, which experimentally connects the worlds of quantum mechanics and classical physics and could shed light on the poorly understood world of non-equilibrium physics. (Image courtesy Valerii Vinokur/Science, Argonne National Lab Press Release)
An international team of researchers, including the MESA+ Institute for Nanotechnology at the University of Twente in The Netherlands and the U.S. Department of Energy’s Argonne National Laboratory, have announced the observation of a dynamic Mott transition in a superconductor. 
The discovery experimentally connects the worlds of classical and quantum mechanics and illuminates the mysterious nature of the Mott transition. It also could shed light on non-equilibrium physics, which is poorly understood but governs most of what occurs in our world. The finding may also represent a step towards more efficient electronics based on the Mott transition.
Since its foundations were laid in the early part of the 20th century, scientists have been trying to reconcile quantum mechanics with the rules of classical or Newtonian physics (like how you describe the path of an apple thrown into the air—or dropped from a tree). Physicists have made strides in linking the two approaches, but experiments that connect the two are still few and far between; physics phenomena are usually classified as either quantum or classical, but not both.
One system that unites the two is found in superconductors, certain materials that conduct electricity perfectly when cooled to very low temperatures. Magnetic fields penetrate the superconducting material in the form of tiny filaments called vortices, which control the electronic and magnetic properties of the materials.
These vortices display both classical and quantum properties, which led researchers to study them for access to one of the most enigmatic phenomena of modern condensed matter physics: the Mott insulator-to-metal transition.

October 21, 2015

Gold nanoparticles make better catalysts for CO2 recycling than bulk gold metal. Size is crucial though, since edges produce more desired results than corners (red points, above). Nanoparticles of 8 nm appear to have a better edge-to-corner ratio than 4 nm, 6 nm, or 10 nm nanoparticles.(Image Credit: Sun lab/Brown University)

It’s a 21st-century alchemist’s dream: turning Earth’s superabundance of carbon dioxide — a greenhouse gas — into fuel or useful industrial chemicals. Researchers from Brown have shown that finely tuned gold nanoparticles can do the job. The key is maximizing the particles’ long edges, which are the active sites for the reaction.

By tuning gold nanoparticles to just the right size, researchers from Brown University have developed a catalyst that selectively converts carbon dioxide (CO2) to carbon monoxide (CO), an active carbon molecule that can be used to make alternative fuels and commodity chemicals.

“Our study shows potential of carefully designed gold nanoparticles to recycle CO2 into useful forms of carbon,” said Shouheng Sun, professor of chemistry and one of the study’s senior authors. “The work we’ve done here is preliminary, but we think there’s great potential for this technology to be scaled up for commercial applications.”

Categories : University News
October 15, 2015

This shows a slab through the 3-D reconstruction of particle 1 along the vertical plane with tentative atomic positions indicated. ABC repeats of {111} planes are visible. (Image Credit Monash University)

Researchers have developed a new method to capture the 3D structures of nanocrystals. Scientists believe these tiny particles could be used to fight cancer, collect renewable energy and mitigate pollution.

Metallic nanoparticles are some of the smallest particles. Their dimensions are measured in nanometres, with each nanometre being one millionth of a milimetre. Until now, it has been difficult to know how they work, because they are so small their structure is impossible to see.

The novel imaging method, developed by an international team from the US, Korea and Australia will allow researchers to investigate the 3D structure of these miniscule particles for the first time.

The research, published today in Science, was co-led by Associate Professor Hans Elmlund from the ARC Centre of Excellence in Advanced Molecular Imaging based at Monash University. The work, performed in collaboration with researchers from Princeton University, Boston University, and Harvard, reveals the details of the method and shows how it can be used to characterise the 3D structures of these miniscule particles for the first time.

The method is called “3D Structure Identification of Nanoparticles by Graphene Liquid Cell EM (SINGLE)” and it exceeds previous techniques by combining three recently developed components.

Categories : University News
October 07, 2015

Co-crystal structure of protein-DNA nanowires. The protein-DNA nanowire design is experimentally verified by X-ray crystallography.Credit: Yun (Kurt) Mou, Jiun-Yann Yu, Timothy M. Wannier, Chin-Lin Guo and Stephen L. Mayo/Caltech

The ability to custom design biological materials such as protein and DNA opens up technological possibilities that were unimaginable just a few decades ago. For example, synthetic structures made of DNA could one day be used to deliver cancer drugs directly to tumor cells, and customized proteins could be designed to specifically attack a certain kind of virus. Although researchers have already made such structures out of DNA or protein alone, a Caltech team recently created—for the first time—a synthetic structure made of both protein and DNA. Combining the two molecule types into one biomaterial opens the door to numerous applications.

Mou and his colleagues in the laboratory of Stephen Mayo, Bren Professor of Biology and Chemistry and the William K. Bowes Jr. Leadership Chair of Caltech's Division of Biology and Biological Engineering, began with a computer program to design the type of protein and DNA that would work best as part of their hybrid material. "Materials can be formed using just a trial-and-error method of combining things to see what results, but it's better and more efficient if you can first predict what the structure is like and then design a protein to form that kind of material," he says.

Categories : University News
September 28, 2015

Graphene, like the paper models, is strong but flexible, and can be stretched or pulled with forces comparable to those exerted by motor proteins. Image Credit: Joe Wilensky/Cornell Chronicle

The art of kirigami involves cutting paper into intricate designs, like snowflakes. Cornell physicists are kirigami artists, too, but their paper is only an atom thick, and could become some of the smallest machines the world has ever known.

A research collaboration led by Paul McEuen, the John A. Newman Professor of Physical Science and director of the Kavli Institute at Cornell for Nanoscale Science (KIC), is taking kirigami down to the nanoscale. Their template is graphene, single atom-thick sheets of hexagonally bonded carbon, famous for being ultra thin, ultra strong and a perfect electron conductor. The team demonstrated the application of kirigami on 10-micron sheets of graphene (a human hair is about 70 microns thick), which they can cut, fold, twist and bend, just like paper.

Graphene and other thin materials are extremely sticky at that scale, so the researchers used an old trick to make it easier to manipulate: They suspended it in water and added surfactants to make it slippery, like soapy water. They also made gold tab “handles” so they could grab the ends of the graphene shapes. Co-author Arthur Barnard, also a Cornell physics graduate student, figured out how to manipulate the graphene this way.

Categories : University News
September 21, 2015

Image Credit: Bilkent University UNAM

Memristors, resistors of which conductance is a function of the history of voltage applied to them, have attracted great attention in the present decade as potential components of memory and computing platforms. These long-forgotten device components were predicted over fifty years ago by Leon Chua, who described them as the fourth fundamental circuit element alongside resistors, capacitors and inductors – although the true origins of the memristor are even older than its name, as the term applies to such a broad range of electronic phenomena that the original observations of memristive behavior date over a century ago.

In the modern world, however, memristors are making a comeback: They are expected to play a major role in the development of novel computing platforms, particularly neuromorphic systems, where brain-like (cortical) computational schemes can be efficiently implemented using semiconductor technology. Recent reports on memristive switches demonstrate improvements in the uniformity and controllability of nanoionics-based memristors, though there is still a long way to go before memristors can compete with other circuit elements in forming neuromorphic systems with billions of synapses and millions of solid state neurons. On the other hand, Flash memory -another non-volatile memory technology- has reached very high densities and is readily compatible with CMOS technology, which makes it a particularly suitable model for the implementation of memristor-based applications.

In recent work at the National Nanotechnology Research Center at Bilkent University (Turkey), the Dâna group has demonstrated that junctionless flash memory cells can be operated like a memristor: The write and erase operations commonly performed through voltage pulses applied to the gate can be effected through the application of voltages through the source and drain terminals of the transistor. In fact, the equations that relate the transistor operation and charge/discharge of the floating gate show that the flash memory, when operated in this way, behaves nearly like an ideal memristor. The significance of the demonstration is that it connects the two non-volatile memory device families, the memristor and flash, and may facilitate future applications of flash memory devices in neuromorphic computing. Considering that the density of flash drives has improved to such an extent that multigigabit chips can be mass produced and have entered into virtually every cell-phone, flash technology already has the infrastructure that can enable the implemention of billions of synthetic synapses. Moreover, the flashristor mode -the new operation mode is referred to in the article- can be implemented with high uniformity and repeatability.

The group’s findings are also highlighted in the IEEE Spectrum website, which can be found at:

http://spectrum.ieee.org/tech-talk/computing/hardware/flashristors-getting-the-best-of-memristors-and-flash-memory

September 11, 2015

The image above illustrates how proteins (copper-colored coils) modified with polyhistidine-tags (green diamonds) can be attached to nanoparticles (red circle). Credit: Jonathan Lovell/University at Buffalo.

Fastening protein-based medical treatments to nanoparticles isn’t easy. With arduous chemistry, scientists can do it. But like a doomed marriage, the fragile binding that holds them together often separates. This problem, which has limited how doctors can use proteins to treat serious disease, may soon change. University at Buffalo researchers have discovered a way to easily and effectively fasten proteins to nanoparticles – essentially an arranged marriage – by simply mixing them together. While in its infancy, the model already has shown promise for developing an HIV vaccine and as a way to target cancer cells. “Scientists have been able to attach proteins to nanoparticles for a while now. But it’s a fairly difficult process that’s only effective in a controlled environment. Nobody has been able to devise a simple method that can work inside the body,” said Jonathan F. Lovell, PhD, UB assistant professor of biomedical engineering, who led the research. He added: “We have proven that you can easily attach proteins to nanoparticles and, like Velcro that doesn’t unstick, it stays together.” Additional authors include researchers from UB’s Department of Chemical and Biological Engineering and Department of Microbiology and Immunology. The teams’ results were exciting, with the new binding model acting like a homing missile to tumors. The targeted nanoparticles have the potential to improve cancer treatment by targeting specific cancer cells in lieu of releasing anti-cancer drugs everywhere in the body. Lovell plans to follow up the research with more rigorous testing of the vaccine and tumor-targeted technologies. Moving to human clinical trials is the ultimate goal.

Categories : University News
September 04, 2015

Zinc oxide nanowires return to shape slowly after being bent. That property, called anelasticity, suggests that nanowires might be good in applications that require absorption of shocks or vibrations. Image Credit: Brown University Zhu lab / NC State
Researchers from Brown University and North Carolina State University have found that nanowires made of zinc oxide are highly anelastic, meaning they return to shape slowly after being bent, rather that snapping right back. The findings add one more to the growing list of interesting properties found in nanoscale wires, tiny strands thousands of times thinner than a human hair. “What’s surprising here is the magnitude of the effect,” said Huajian Gao, the Walter H. Annenberg Professor of Engineering and a coauthor of a new paper describing the research. “Anelasticity is present but negligible in many macroscale materials, but becomes prominent at the nanoscale. We show an anelastic effect in nanowires that is four orders of magnitude larger than what is observed in even the most anelastic bulk materials.”
The findings are significant in part because anelastic materials are good absorbers of kinetic energy. These results suggest that nanowires could be useful in damping shocks and vibrations in a wide variety of applications.
“During the last decade, zinc oxide nanowire has been recognized as one of the most important nanomaterials with a broad range of applications such as mechanical energy harvesting, solar cells, sensors and actuators,” Gao said. “Our discovery of giant anelasticity and high energy dissipation in zinc oxide nanowires adds a new dimension to their functionality.” The experiments for the study were done in the lab of Yong Zhu, an associate professor of mechanical and aerospace engineering at NC State. Zhu and his colleagues used a delicate apparatus to bend nanowires under a scanning electron microscope. The work showed that, after the bending strain was released, the wires returned to about 80 percent of their original shape quickly. But they recovered the rest of their original shape much more slowly, over the course of up to 20 or 30 minutes. That is a far more prominent anelastic effect than is common at the macroscale.

Categories : University News
August 28, 2015

Graphene, like the paper models, is strong but flexible, and can be stretched or pulled with forces comparable to those exerted by motor proteins. Image Credit: Joe Wilensky/Cornell Chronicle, Cornell University

The art of kirigami involves cutting paper into intricate designs, like snowflakes. Cornell physicists are kirigami artists, too, but their paper is only an atom thick, and could become some of the smallest machines the world has ever known. A research collaboration led by Paul McEuen, the John A. Newman Professor of Physical Science and director of the Kavli Institute at Cornell for Nanoscale Science (KIC), is taking kirigami down to the nanoscale. Their template is graphene, single atom-thick sheets of hexagonally bonded carbon, famous for being ultra thin, ultra strong and a perfect electron conductor. They have demonstrated the application of kirigami on 10-micron sheets of graphene (a human hair is about 70 microns thick), which they can cut, fold, twist and bend, just like paper. Graphene and other thin materials are extremely sticky at that scale, so the researchers used an old trick to make it easier to manipulate: They suspended it in water and added surfactants to make it slippery, like soapy water. They also made gold tab “handles” so they could grab the ends of the graphene shapes. Arthur Barnard, also a Cornell physics graduate student, figured out how to manipulate the graphene this way.

Categories : University News

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