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Gold Nanoparticles Might Make a Non-Toxic Treatment for Lymphoma

Gold in nanoparticle form is perhaps more precious than the macroscale variety when it comes to treating diseases. While the usual application areas for nanotechnology, such as electronics, are finding uses for gold nanoparticles, it is perhaps in the area of drug delivery and the detection and treatments of diseases such as cancer where they are destined to have their biggest impact.

Along these lines, researchers at Northwestern University have used gold nanoparticles to treat a common form of cancer, known as B-cell lymphoma—the most common type of non-Hodgkin lymphoma.

In research to be published in the journal Proceedings of the National Academy of Sciences, C. Shad Thaxton, M.D., and Leo I. Gordon, M.D. showed that they could trick B-cell lymphoma, which prefers to eat HDL (high-density lipoprotein) cholesterol—otherwise known as the “good cholesterol”—into eating gold nanoparticles instead of the HDL. Once the B-cell lymphoma cells start eating the gold nanoparticles (or artificial HDL particles), they get plugged up and can no longer feed on any more cholesterol. Deprived of their favorite food, the lymphoma cells essentially starve to death.

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When You Keep Nanotubes Short, They’re Not Like Asbestos

For at least the past five years, NGOs committed to seeing nanotechnology research stopped dead in its tracks have trotted out Ken Donaldson’s research at the University of Edinburgh to support their aims. Donaldson’s research indicated that multi-walled nanotubes (MWNTs) that are longer than 20 μm have a similar pathogenic effect to asbestos.

The writing was on the wall right from the beginning for any concern this research might have generated. The common sense question was: What if you kept the MWNTs short?

Richard Jones essentially raised this question on his blog at the time of Donaldson publishing his research in Nature Nanotechnology: “Not all carbon nanotubes are equal when it comes to their toxicity. Long nanotubes produce an asbestos-like response, while short nanotubes, and particulate graphene-like materials don’t produce this response.”

Five years later and we have experimental confirmation that the way to reduce the pathogenic risk from MWNTs is to keep them short. In research published in the journal Angewandte Chemie (“Asbestos-like Pathogenicity of Long Carbon Nanotubes Alleviated by Chemical Functionalization”), Professor Kostas Kostarelos at the University College London’s School of Pharmacy found that if you chemically functionalized MWNTs so they become shorter, then they are a safe and risk-free material.

“The apparent structural similarity between carbon nanotubes and asbestos fibres has generated serious concerns about their safety profile and has resulted in many unreasonable proposals of a halt in the use of these materials even in well-controlled and strictly regulated applications, such as biomedical ones,” said Kostarelos in a university press release. “What we show for the first time is that in order to design risk-free carbon nanotubes both chemical treatment and shortening are needed.”

This certainly doesn’t put the issue to rest. Not for the reasons that NGOs will likely employ—which will  be to ignore this most recent research—but because how can we be assured that MWNTs used in a material matrix do not exceed 20 μm in length? Further, what about the safety of the workers who handle the MWNTs before they are chemically functionalized (shortened)?

Sound scientific research is still needed and it will in all likelihood be pursued. Whether this will satisfy those who are well-versed in how to leverage preliminary studies into scare screeds remains to be seen. When more in-depth research finds that those preliminary studies were not as well founded as they made others believe, the fear mongers typically remain defiant in part through dismissing the latest research.

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Faster and Cheaper Process for Graphene in Li-ion Batteries

Over the last couple of years, research to improve lithium-ion (Li-ion) batteries have been turning to graphene, particularly after researchers at Northwestern University successfully sandwiched a layer of silicon between graphene sheets in the anodes of Li-ion batteries.

But most of the Li-ion battery work being done with graphene to date has depended on high-vacuum environments to create the layered material. Now Gurpreet Singh, a Kansas State University assistant professor of mechanical and nuclear engineering, is leading a team that's looking at faster and cheaper ways of synthesizing the material.

"We are exploring new methods for quick and cost-effective synthesis of two-dimensional materials for rechargeable battery applications," Singh said in a university press release.

The two-dimensional materials to which Singh refers includes not only graphene but also tungsten disulfide nanosheets. In his work with graphene, which was published in the journal Applied Materials & Interfaces (“Synthesis of Graphene Films by Rapid Heating and Quenching at Ambient Pressures and Their Electrochemical Characterization”),Singh’s team was able to create the graphene outside of a vacuum.

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Graphene Could Help Prevent Another Lance Armstrong

After a professional cycling career in which he claimed repeatedly to have never given a positive drug test, Lance Armstrong has reportedly confessed to using performance-enhancing drugs in achieving his Tour de France victories.

While his confession will likely raise a lot of questions, surely one has to be how could the drug tests have failed in detecting the illicit drugs? Great advances have been made in drug testing since Lance Armstrong won his first Tour de France in 1999. At that time, there was no test for EPO—the drug of choice of endurance athletes looking for an edge—but a test was developed in 2000. Nonetheless, Armstrong and many others who have recently confessed got away with it between 2000 and now despite the new tests.

Now drug testing may have a new ally in combating cheating in professional cycling and all professional sports. Researchers at the University of Manchester in the UK in cooperation with colleagues at Aix-Marseille University in France are reporting on an optical system—enabled by esoteric stuff such as metamaterials, plasmonics, and singular optics along with the wonder material graphene—to detect a single molecule of a drug in a few minutes.

The research, which is published in the journal Nature Materials (“Singular phase nano-optics in plasmonic metamaterials for label-free single-molecule detection”), is essentially a proof of concept for new sensing devices that exploit the field of singular optics, which operates on the phenomena of abrupt phase changes to light.

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Nanocoatings for Waterproofing Mobile Devices Continue to Make a Splash at CES

Last year’s edition of the Consumer Electronics Show saw the introduction of the waterproof mobile phone. This year’s iteration of CES marks waterproofed gadgets' sophomore year return, and for at least one company, the announcement of a new chemistry for the nanocoating that makes phones more waterproof than they were last year.

In a blog post last year, IEEE Spectrum editor Tekla Perry suggested that a patent battle might be brewing between HzO and Liquipel, makers of the coatings that keep water out. But that intellectual property fight doesn’t seem to have materialized. The patent concerns stemmed from both Liquipel’s and HzO’s relationship with a company called Zagg, which sells and markets protective casings for mobile devices. HzO approached Zagg to help it market its nanocoating product. Later, executives from Zagg left the company to form Liquipel, which raised some suspicions.

From my cynical perspective, I suspected that Liquipel’s recently announced new chemistry was motivated by these patent infringement concerns. But an industry insider informed me that Liquipel’s new chemistry was more likely to have been driven by improving product features than any concerns over patents.

Both Liquipel (Santa Ana, Ca.) and HzO (Draper, Utah) may have been driven to step their respective games up by two other rivals in the market: Neverwet, based in Leola, Pa., and P2i Ltd. of Abingdon, UK. (It should be noted that P2i also has a U.S. subsidiary in Savannah, Ga., P2i Inc.) Each of these four players is looking to grab market share by demonstrating to gadget makers that its nanocoating is better and that its waterproofing process costs less.

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Nanoparticle Enables World Record for Energy Storage in Batteries

With just one week under our belts in this New Year, we already have some world-record news in relation to lithium-ion (Li-ion) batteries and nanoparticles. Researchers at Stanford University and the SLAC National Accelerator Laboratory have developed a Li-ion battery in which its sulfur cathode was capable of storing five times more energy than is possible with today’s commercially available batteries.

The research—not surprisingly—was led by Stanford’s Yi Cui. What may be somewhat surprising is that Cui has focused his attention in this research on the cathode rather than the anode of the battery. Much of Cui’s most recent work has been on improving the anodes of Li-ion batteries through the use of nanostructured silicon. In this latest research, he has not only shifted his attention to the cathode, but also developed an entirely new material to do it.

The new material, which is described in the Jan. 8 edition of Nature Communications (“Sulphur–TiO2 yolk–shell nanoarchitecture with internal void space for long-cycle lithium–sulphur batteries”),  is a nanoparticle that is made up of an inner core of sulfur surrounded by an outer layer of porous titanium-oxide. The nanoparticles architecture resembles that of the yolk and shell of an egg.

This nanoparticle’s new architecture has broken down an obstacle to using sulfur in the cathode of Li-ion batteries that has persisted for around 20 years.

While it has been known that sulfur could store more lithium ions than other cathode materials, the combination of sulfur atoms with lithium ions resulted in a compound—though necessary for the cathode to operate—that kept dissolving and limited the storage capacity of the battery. Also, when the lithium ions went into the cathode, it would expand the size of the cathode by 80 percent. Attempts to employ protective coatings to correct the first problem of the compound dissolving just resulted in them cracking as soon the lithium ions expanded the cathode.

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Graphene Takes Aim at Treating Alzheimer’s and Cancer

When graphene was first introduced, it seemed everyone wanted to apply it to electronics, especially after carbon nanotubes were turning into such a disappointment in the field.  But graphene has a huge strike against it in electronics: it lacks a band gap. So everyone, including major electronics players like IBM and Samsung, looked for ways to give graphene a band gap.

While researchers were hard at work wrestling graphene into a role it didn’t seem to want to play, others were looking at what it might like to do. This led to work that looked at using graphene for applications ranging from rustproofing to photovoltaics.

Now the biomedical field is increasingly looking at graphene as a material for advancing therapeutics and diagnostics where its capabilities might be ideally suited. An article in the journal Advanced Materials ("New Horizons for Diagnostics and Therapeutic Applications of Graphene and Graphene Oxide") outlines some of the ways that graphene and its oxide are promising improved diagnostics and therapeutics for maladies ranging from Alzheimer’s to cancer.

Of course, some of the applications for graphene in the biomedical field are within areas that are at least tangential to those already mentioned, like electronic devices and transparent conductors. But graphene is also being looked at for drug and gene delivery applicationsphoto-therapy of cancer  and biosensors. In particular, researchers have been experimenting with combining graphene with near-Infrared (NIR) phototherapy and imaging.  There has been some progress in using graphene-enabled NIR photothermal therapy for cancer and Alzheimer's disease (AD).

While both pure graphene and graphene oxide have exhibited some toxicity to cell and animals, it has been found that coating the graphene with a biocompatible polymer results in no detectable toxicity in both cellular and animal testing.

Graphene’s application to this field is still in its infancy, however, early testing has shown promise that it could play an important role in future disease diagnostics and treatment.

Image:  Luis E. F. Foa Torres

Graphene Still Trying to Replace ITO in Organic Solar Cells

Almost two years ago, researchers at MIT were heralding graphene as a possible replacement for the expensive indium-tin-oxide used in electrodes for organic solar cells. They showed a way in which the entire solar cell could be flexible—including its electrodes—and transparent.

Not long after that, research at Rice University picked up on the use of graphene for replacing ITO, but aimed their work towards creating a thin film for touch-screen displays.

Now researchers at MIT are reporting on work that, like the Rice team, combines flexible sheets of graphene with a grid of metallic nanowires. In so doing, they turned their attention back to photovoltaics. The research (“Graphene Cathode-Based ZnO Nanowire Hybrid Solar Cells”) was published in the journal Nano Letters.

While this latest research is not the first time graphene was used a replacement for ITO—even at MIT—it does have the distinction of being a graphene-nanowire solar cell with a respectable energy conversion efficiency of 4.2 percent. While this may not sound like a world-beating number, it stands up well to that of ITO-based devices with similar architectures.

“We’ve demonstrated that devices based on graphene have a comparable efficiency to ITO,” says Silvija Gradečak, one of the MIT researchers involved in the project, in a press release. “We’re the first to demonstrate graphene-nanowire solar cells without sacrificing device performance.”

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Fundamental Photoconductivity Mechanisms of Graphene Revealed

A team from the IBM Nanoscale Science and Technology group has revealed some of the fundamental mechanisms of photoconductivity in graphene. In particular, the researchers demonstrated that the photoconductivity of graphene can be either positive or negative depending on its gate bias.

The research team includes Marcus Freitag, Tony Low, Fengnian Xia and Phaedon Avouris (who we interviewed on this blog for his work in creating a band gap in graphene). The group works out of IBM's T. J. Watson Research Lab, in Yorktown Heights, N.Y. and published their work (“Photoconductivity of graphene”) in the online version of Nature Photonics.

The impetus for their “classic photoconductivity experiment” was the appealing optoelectronic properties of graphene. It at once possesses high carrier mobility, zero bandgap, and electron-hole symmetry.

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Nanoparticle Coated Lens Converts Light into Sound for Precise Non-invasive Surgery

Remember how Leonard McCoy performed surgery in Star Trek? He would wave a device over the patient. The outer layers of the skin didn't need not be cut, even when operating on internal organs, and the precision of 23rd century instrument reached down to the level of individual cells.

Well, we already have a bit of that in the 21st. Research at the University of Michigan, led by Jay Gou, has developed a device that employs a carbon-nanotube-coated lens capable of converting light into tightly focused sound waves. The new ultrasound therapeutic tool that reaches new levels of precision—its high-amplitude sound waves are able to target an object with dimensions of 75 by 400 micrometers.

In the image to the right, you can see a150-µm hole that the researchers drilled into a confetti-sized artificial kidney stone.

"A major drawback of current strongly focused ultrasound technology is a bulky focal spot, which is on the order of several millimeters," says Hyoung Won Baac, who worked on the project as a doctoral student and is now a research fellow at Harvard Medical School, in a press release. "A few centimeters is typical. Therefore, it can be difficult to treat tissue objects in a high-precision manner, for targeting delicate vasculature, thin tissue layer and cellular texture. We can enhance the focal accuracy 100-fold."

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Nanoclast

IEEE Spectrum’s nanotechnology blog, featuring news and analysis about the development, applications, and future of science and technology at the nanoscale.

 
Editor
Dexter Johnson
Madrid, Spain
 
Contributor
Rachel Courtland
Associate Editor, IEEE Spectrum
New York, NY
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