NANObits

A Battery Made With Paper

donpatent@gmail.com (donpatent) — Wed, 09 Dec 2009 15:03:00 +0000

Powerful paper. A scanning electron micrograph of uncoated paper fibers (above) and fibers with a carbon nanotube coating (inset).

CREDIT: ADAPTED FROM L. HU ET AL.,PNAS EARLY EDITION (DECEMBER 2009)

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Robert F. Service

ScienceNOW Daily News
8 December 2009

Paper has been getting beat by electronics for years. But it may be about to stage a comeback. Researchers are reporting that they've made batteries and other energy-storage devices by printing layers of carbon nanotube–based ink atop standard photocopy paper. The result is a highly conductive sheet that can carry a charge and be easily incorporated into a flexible battery. Because of paper's low cost, that could help lower the price of batteries used in electric vehicles, wind farms, and other renewable sources.

The idea of using paper to make a lightweight, flexible battery isn't new. Researchers led by Robert Linhardt, a chemist at Rensselaer Polytechnic Institute in Troy, New York, first explored the concept 2 years ago. They cast a thin film of cellulose--the same starting material used to make paper--and laid it over conductive carbon nanotubes. The hope was that the cellulose would serve as a sturdy structural material to hold the other components for making a battery, and it did. But the two layers remained independent and could split apart if flexed.

Yi Cui, a materials scientist at Stanford University in Palo Alto, California, had also been exploring using plastics and other types of thin layers as the structural supports for batteries and supercapacitors (which store energy as static charge, unlike batteries that undergo chemical reactions). But the plastic layers also didn't connect well with the conductive nanotubes placed on top. Conventional copy paper has a highly porous structure. So Cui and his colleagues wondered if that could serve as a good support for their nanotubes.

The researchers created an "ink" of carbon nanotubes suspended in water and an organic surfactant. They then heated the paper in an oven to drive off the water. The nanotubes bonded tightly to the paper fibers, creating a highly conductive sheet of paper that functions even when rolled up. The team then used these conductive sheets as components in both lithium-ion batteries and supercapacitors.

The paper batteries can store up to 7.5 Watt-hours per kilogram (Wh/jg), the team reported online this week in theProceedings of the National Academy of Sciences. That's not quite up to the level of lead acid batteries, which store roughly 30 Wh/kg. But because the cost of nanotubes is coming down, and because paper is cheap and durable, it could open the door to cheaper batteries for large-scale energy storage.

"It's quite innovative and an important contribution," says Linhardt. The fact that the nanotubes and paper fibers hold tight is critical, he adds, because it now enables engineers to make batteries in almost any shape. Paper's strength could also help battery makers reduce the thickness of the electrodes they use to make batteries, which in many cases are made thick to provide structural support for the batteries. And that reduced amount of electrode material could further reduce the battery's cost.

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Credit: Jack Hubbard/Standford News Service

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Magnetic microdiscs target and initiate cell death in tumors

donpatent@gmail.com (donpatent) — Fri, 04 Dec 2009 14:34:00 +0000

By ANN WANG
Issue date: 12/3/09

Scientists working at Argonne National Laboratory in Chicago and The University of Chicago have developed an effective method to target and kill cancer cells using tiny magnetic discs.

The microdiscs, only one micron in diameter, work by disrupting the outer membranes and initiating chemical pathways that lead to apoptosis, or cell death. In laboratory tests, the microdiscs destroyed up to 90 percent of cancer cells after being activated for only 10 minutes.

One major drawback of chemotherapy drugs, widely used to treat cancers, is that they cannot be targeted to tumor cells. These drugs affect the entire body and often cause painful side effects such as hair loss, nausea, fatigue and a weakened immune system.

For several decades, scientists have been trying to develop nanoparticles that can deliver drugs specifically to cancer cells. Although several such methods are now being tested in clinical trials, practical hurdles still remain.

Up until now, effective treatments required high concentrations of magnetic particles and high levels of power to activate them. Both could cause harmful side effects in patients.

The new research offers a potential solution to many of these problems. The team studied an aggressive brain cancer called glioblastoma multiforme. The surfaces of these cancer cells, called glioma cells, contain a much higher concentration of a protein called IL13 than normal cells do.

The microdiscs, each 60 nm wide and 1000 nm in diameter, were made of an iron and nickel alloy, then coated with a thin gold veneer. Gold is both nontoxic to living tissues and easy to modify with organic molecules. The gold-covered microdiscs were then coated with antibodies that would recognize and bind to the overexpressed protein on glioma cells.

Once introduced into the body, or in this case a cell culture, the antibodies guide the microdiscs to attach to the surface of the cancerous glioma cells, but not healthy cells. About 10 microdiscs attached to each cancer cell.

Because they are discs instead of particles, and much wider than they are thick, the microdiscs have a magnetic property known as a spin-vortex ground state, and they oscillate when an alternating current is applied.

The cell membrane consists of a fluid double layer of lipid molecules, more like the film that forms over a bowl of cold soup. This fluid membrane is easily disrupted by the twisting and turning motion of the microdiscs attached to its surface.

"The spin-vortex-mediated stimulus creates two dramatic effects: compromised integrity of the cellular membrane . . . and initiation of programmed cell death," said Elena Rozhkova, a research scientist at Argonne National Laboratory who worked on the study.

After they activated the microdiscs, the researchers noticed that most of the cancer cells looked like they were undergoing apoptosis, the controlled pathway towards death that normal cells are programmed to follow once they reach the end of their useful lives.

Cancer cells have developed mutations that allow them to escape cell cycle control and apoptosis. Instead of dying when they should, they divide and grow continuously, forming tumors.

However, the microdisc-treated glioma cells had fragmented DNA and nuclei, rounded shapes and irregular surface bulges (scientific term: blebs), all classic signs of cells undergoing apoptosis.

But the force the microdiscs exerted could not have caused such striking changes in the cells alone. In fact, the torque exerted by the microdiscs was less than one tenth of the torque needed even to break the outer membrane.

It was clear that the surface disruptions that the discs created were activating a signaling pathway inside the cell that led to apoptosis.

The researchers found that microdisc-treated cells had much higher concentrations of calcium than usual. Calcium plays a major role in many cell pathways and is known to be a key signaling molecule in apoptotic pathways.

Previous studies had also shown that even minor, temporary cell membrane disturbances can raise calcium levels within cells. It seems likely that the mechanical stimulus provided by the microdiscs is then amplified as a chemical signal inside the cell, leading the cell to begin apoptosis.

One key advancement in the team's research was that because of the material used to make the discs, a relatively low frequency and short treatment time was enough to kill most cancer cells. The relative mildness of the treatment may help decrease side effects in vivo.

"Using the unique 'soft' magnetic material allows application of a low-frequency field of a few tens of hertz applied for only ten minutes, [which] was sufficient to achieve approximately 90% cancer-cell destruction in vitro," Rozhkova said. "This is 10-100,000 times weaker magnetic field that it is used for superparamagnetic particles."

Although these new findings offer a promising new way that nanotechnology can be used to treat cancer, more work needs to be done before clinical trials can begin.

Source

Ref:

Ferromagnetic microdisks as carriers for biomedical applications

J. Appl. Phys. 105, 07B306 (2009); doi:10.1063/1.3061685

Published 5 March 2009
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ABSTRACT
REFERENCES (10)
CITING ARTICLES
E. A. Rozhkova,¹ V. Novosad,² D.-H. Kim,² J. Pearson,² R. Divan,¹ T. Rajh,¹ and S. D. Bader²
¹Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, USA
²Materials Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
Wereport the fabrication process, magnetic behavior, as well as thesurface modification of ferromagnetic microdisks suspended in aqueous solution. Theyposses unique properties such as high magnetization of saturation, zeroremanence due to spin vortex formation, intrinsic spin resonance atlow frequencies, and the capability of delivering various biomolecules atonce. Furthermore, because of their anisotropic shape, our magnetic particlesrotate under alternating magnetic fields of small amplitude. This canbe used to promote the idea of advanced therapies, whichinclude combined drug delivery and magnetomechanical cell destruction when targetingtumor cells. The approach enables us to fabricate suitable magneticcarriers with excellent size tolerances, and then release them fromthe wafer into solution, ready for surface modification and therapeuticuse. The particles have a magnetic core and are coveredwith few nanometers of gold on each side to providestability at ambient conditions as well as biocompatibility and selectiveadhesion functions. A successful attempt to bind thiolates, including SH-modifiedantibody, to the disk's surface was demonstrated. ©2009 American Institute of Physics
History: Presented 12 November 2008; received 13 October 2008; accepted 23 October 2008; published 5 March 2009
Permalink: http://link.aip.org/link/?JAPIAU/105/07B306/1

Conquering cancer with implants? Bioengineered vaccines and magnetic nanodiscs show promise

donpatent@gmail.com (donpatent) — Sun, 29 Nov 2009 21:12:00 +0000

Nov 29, 2009 01:01 PM in Health & Medicine | Post a comment

By Katherine Harmon

Rather than surgically removingtumors, what if doctors could simply implant new tools in our bodies to do the work internally? One team of researchers has been able to vanquish tumors in mice by implanting bioengineered disks filled with tumor-specific antigens, and another has developed magnetized nanodiscs to induce cancer cells destroy themselves.

Numerous cancer vaccines have shown promise in animal models only to later fail to generate results in humans. But an implant-based approach may hold the key, according to a team of immunologists and bioengineers at Harvard University. They designed a tiny polymer disk saturated with dendritic cells and antigens specifically tuned to go after tumor cells. The results, published online November 25 in Science Translational Medicine, show "the power of applying engineering approaches to immunology," David Mooney, a professor of bioengineering ant Harvard's School of Engineering and Applied Sciences, said in a prepared statement.

The principal is the same as a vaccine: prompt the immune system to attack invading cells. However, unlike previously tested injected cancer vaccines, cells from the disk are less prone to die before they can get the job done.

The 8.5-millimeter biodegradable disk can be "inserted anywhere under the skin—much like the implantable contraceptives that can be placed in a woman's arm," Mooney said. "The implants activate an immune response that destroys tumor cells." When the disks were implanted in mice with melanoma, the treatment led to remission and longer lives in "a substantial portion of the population," the authors reported.

Another trick to zapping cancer cells may lie in nano-scale magnets. Previous studies have investigated the use of magnetic fields to kill cancer cells via hyperthermia, but they required a lot more power than the new method and proved to have some dangerous side effects.

A new study, published November 29 in Nature Materials, reports promise in a scaled-down version of this idea to tackle tumors. "Nanomagnetic materials offer exciting avenues for probing cell mechanics and…advancing cancer therapies," the paper authors wrote. Using nanodiscs (about 60 nanometers thick) made of iron and nickel, researchers based in the Argonne National Laboratory in Illinois and the University of Chicago Pritzker School of Medicine have created a so-called "magnetic vortex" in the magnetic alloy with the magnetic charge arranged in concentric circles. "Integration of magnetic materials with biological molecules and therapeutics creates hybrid materials with advanced properties," the authors noted in the paper.

By introducing an alternating magnetic field, researchers made the discs oscillate, thereby damaging the membranes of cancer cells in the lab and causing the cells to die. The researchers needed only a frequency of "a few tens of hertz applied for only 10 minutes" to "achieve cancer-cell destruction in vitro," they wrote. With this approach they rely on neither heat nor mechanical assault, but rather on the oscillation "which triggers the programmed cell-death pathway" via an ionic electrical signal, the authors explained. Thus, "the total energy necessary to accomplish cell death is minute."

While these innovative implant technologies are being tested in the lab, however, cancer continues to be one of the leading causes of death in the U.S. (second only to heart disease), killing more than half a million people last year.

Image of polymer matrix (next to dime for size comparison) courtesy of InCytu, Inc.

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Self-Taught Inventor Creates Homemade Electric Wheelchair

donpatent@gmail.com (donpatent) — Sun, 29 Nov 2009 00:01:00 +0000

Li Rongbiao, a 67 year old pensioner and inventor, is making headlines in China because of his handmade electric chairs. Also known as the Walking Chair, it is assembled from spare parts and consists of spare wheels that ease stairway access for wheelchairs.

Rongbiao started playing around with the idea of an affordable electric wheelchair when his wife ended up with a broken leg. It so happened that in this period, they faced a number of hassles, including difficulty accessing their fifth floor apartment.

That’s how this self-made inventer found himself buying computer books and looking for financing for his project.

However, the building of the chair took a bit of time since Rongbiao first had to handle all the basics. Thus, he taught himself computer designing for 6 months before spending the rest of the year constructing his dream chair.

As for funding, the innovator was so dedicated to this dream that he pooled all of his income into this project.

This included his savings, pension money as well as odd $70,000 he made from the sale of his apartment.

All this effort is not in vain as his Walking Chair is gaining popularity in China.

In fact, after he demonstrated his invention at one of the biggest disability shows in China, he has been receiving orders for the electric chair. And so, following his visit to this expo, interested parties have bought 30 of his Walking Chairs and there is still a backlog of more than 300 orders.

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Radical new technology could end drilling and filling misery at the dentist

donpatent@gmail.com (donpatent) — Fri, 27 Nov 2009 17:47:00 +0000

Scientists in Britain have developed a mouthwash that allows plaque-causing bacteria to be destroyed using nothing but a bright light, the light could possibly be attached to the head of a toothbrush.

The researchers say they have been experimenting with standard white light such as a conventional security light.

The new technology works in much the same way as some skin cancer treatments and may be available within three years for use at home.

According to the research team at Leeds Dental Institute a “repair solution” to help the body grow new enamel is also being developed which could do away with the need for “drilling and filling”.

The two projects are led by Professor Jennifer Kirkham, who believes they could make a big difference to dental care.

Professor Kirkham says the mouthwash which uses “photodynamic therapy” could help people who find it hard to use a toothbrush and could also be used to treat gum disease which is a major cause of tooth loss.

Antibacterial molecules in the mouthwash are absorbed only by plaque-causing bacteria, and activated when a bright light is shone into the mouth, killing them.

The technique is similar to that used in certain types of skin cancer, where the substance is painted on the target area, taken up by cancer cells, then exposed to light of a certain wavelength, which activates it to kill the cancer cell.

The researchers say though the molecule is considered to be safe for human consumption, full trials have yet to be completed.

Professor Kirkham says the team are looking for safe new ways to control plaque which do not rely on toothpaste as many who are disabled in some way or another are not able to brush effectively.

Researcher Dr Simon Wood says machines offering photodynamic therapy in dental clinics are already in use, but the aim was to find a way the mouthwash could be used at home.

The “repair solution” which is made from a protein which encourages the laying down of new enamel over microscopic holes in teeth, including those caused by acid produced by plaque bacteria.

The solution is painted on the teeth, it enters the holes and creates a scaffold, it then attracts the calcium needed to patch them.

Professor Kirkham says it could help people with early damage which could eventually lead to dental decay, or those who have tiny holes in their teeth which make consuming hot or cold food or drink painful.

The repair solution will not totally eliminate the need for the dentist’s drill as bigger cavities filled with decay would still have to be treated in the conventional manner.

It is hoped that trials will begin next year and a licence for wider use gained within five years.

November 27th, 2009

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Multiple sclerosis 'blood blockage theory' tested

donpatent@gmail.com (donpatent) — Fri, 27 Nov 2009 14:24:00 +0000

By Michelle Roberts
Health reporter, BBC News

The answer may lie with blood flow

US scientists are testing a radical new theory that multiple sclerosis (MS) is caused by blockages in the veins that drain the brain.

The University of Buffalo team were intrigued by the work of Italian researcher Dr Paolo Zamboni who claims 90% of MS is caused by narrowed veins.

He says the restricted drainage, visible on scans, injures the brain leading to MS.

He has already widened the blockages in a handful of patients.

The US team want to replicate his earlier work before treating patients.

Experts welcomed the research saying it was important to confirm the basic science before evaluating any therapy.

MS is a long-term inflammatory condition of the central nervous system which affects the transfer of messages from the nervous system to the rest of the body.

This is not something patients can expect as a treatment now. This is experimental work and is being tested

A spokeswoman for the MS Society

The Buffalo team, led by Dr Robert Zivadinov, plan to recruit 1,100 patients with MS and 600 other volunteers as controls who are either healthy or have neurological diseases other than MS.

Using Doppler ultrasound, they will scan the patients to see if they can find any blockages within the veins of the neck and brain.

If they can prove Dr Zamboni's theory of "chronic cerebrospinal venous insufficiency", they say it will change our understanding of MS.

Rewriting science

Margaret Paroski, who is chief medical officer at Kaleida Health, where the Buffalo researchers are based, said the work could overturn prevailing wisdom that the damage in MS is predominantly the result of abnormal immune responses.

"When I was in medical school, we thought peptic ulcer disease was due to stress. We now know that 80% of cases are due to a bacterial infection.

I found the evidence of narrowing - narrowing of the veins just in MS patients

Dr Zamboni

"Dr Zivadinov's work may lead to a whole different way of thinking about MS."

Dr Zamboni, of the University of Ferrara, believes the blockages are the cause rather than the consequence of MS and that they allow iron from the blood to leak into the brain tissue, where it causes damage.

He has performed procedures similar to angioplasty to unblock the veins and get the blood flowing normally again.

He claims this "liberation procedure" can alleviate many of the symptoms of MS and is due to publish his findings in the Journal of Vascular Surgery.

In an interview with CTV News in Canada he said: "I found the evidence of narrowing - narrowing of the veins just in MS patients.

"I'm fully convinced that this is very, very important for people."

Early days

Kevin Lipp, an MS patient from the US, has been symptom-free since being treated by Dr Zamboni.

He said: "It's only been 10 months. If nothing happens in the next two to three years, we'll know it's working."

The BBC has heard anecdotally of other surgeons in Europe testing out the same treatment.

The MS Society said more research was needed to see if this was an avenue that should be explored further.

"This is not something patients can expect as a treatment now. This is experimental work and is being tested. We need to know more about its safety and effectiveness."

Helen Yates, of the MS Resource Centre, said: "There is no doubt that this area warrants a great deal more study.

"This could represent a completely novel approach to MS research which, if proven to be relevant, could be a "sea change" in the understanding of the mechanisms involved in the condition."

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Tailor-Made HIV/AIDS Treatment Closer to Reality

donpatent@gmail.com (donpatent) — Thu, 26 Nov 2009 14:47:00 +0000

ScienceDaily (Nov. 26, 2009) — An innovative treatment for HIV patients developed by McGill University Health Centre researchers has passed its first clinical trial with flying colours. The new approach is an immunotherapy customized for each individual patient, and was developed by Dr. J-P. Routy from the Research Institute of the MUHC in collaboration with Dr. R. Sékaly from the Université de Montréal. "This is a vaccine made for the individual patient -- an "haute couture" therapy, instead of an off-the-rack treatment" said Dr Routy.

By "priming" the immune system, as with a vaccine, to fight the specific strain of HIV/AIDS infecting a given patient, the scientists believe they have developed a therapy that shows immense promise and could be an even more effective weapon against the virus than the anti-retroviral cocktails currently in use. The results of the first-stage clinical trials, which tested the therapy in conjunction with anti-retroviral drugs, were published recently in Clinical Immunology. Phase 2 of the clinical trial, which is nearly complete, is testing the therapy's efficacy on its own at 8 different sites in Canada.

The new therapy uses dendritic cells which are removed from each HIV-infected patient and subsequently multiplied in-vitro. Dendritic cells present material from invading viruses on their surface, allowing the rest of the immune system to identify and attack the invaders. "They are the "grand conductors" of the immune response," explains Dr Routy. "With them, you push the immune system, in all its functions, at the same time." In the current trial, dendritic cells were exposed to a sample of HIV RNA (ribonucleic acid) specific to the patient involved. This exposure encouraged the cells to develop defences specific to that viral strain. The modified cells -- called AGS-004 -- were then injected back into the patients.

Not only were there few reported side-effects from the AGS-004, but the researchers also measured increased levels of CD8-lymphocytes in the patients -- the "attack" cells of the human immune system that the treatment is intended to mobilize, thus confirming that the intervention was targeted and controlled.

By boosting the immune system in this way, Routy hopes to develop an HIV/AIDS treatment that will require fewer injections and less long-term toxicity for patients than antriretrovirals.

Dr. Jean-Pierre Routy is a practitioner in the Division of Hematology at the MUHC as well as a researcher in the Infection and Immunity Axis at the Research Institute of the MUHC. He is also an Associate Professor of Hematology at McGill University in addition to a senior clinical researcher with the Fonds de la Recherche en Santé du Québec (FRSQ).

This study was funded by a grant from the Canadian Network for Vaccines and Immunotherapeutics (CANVAC), the Canadian HIV Trials Network (CTN), the National Institutes of Health (NIH) and Argos Therapeutics.

This article was co-authored by Rafick-Pierre Sékaly, Université de Montréal, Mohamed-Rachid Boulassel of the McGill University Health Centre (MUHC), Bader Yassine-Diab and Oleg Yegorov of the Université de Montréal and Centre Hospitalier de l'Université de Montréal (CHUM), Lothar Finke, Don Healey, Renu Jain, Tamara Monesmith ,Charles Nicolette and Irina Tcherepanova of Argos Therapeutics, In, Durham, USA.

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Rectal cancer tumour destroyed by ultrasound

donpatent@gmail.com (donpatent) — Thu, 26 Nov 2009 14:26:00 +0000

Thursday, 26 November 2009

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Almost 38.000 patients suffer from rectal cancer per year in the UK

A patient with rectal cancer has become the first to have part of their tumour destroyed by ultrasound, say UK doctors.

A team of radiologists, surgeons and oncologists at Hammersmith Hospital in London used high intensity ultrasound to heat up and kill the cancer.

They say the technique will allow faster and more accurate targeting of tumours than conventional treatments.

Hammersmith Hospital will offer the treatment to advanced stage patients.

High intensity focused ultrasound (HIFU) is carried out under general anaesthetic.

The device can treat tumours up to about 40cc volume and can heat the tissue up to 90 degrees centigrade

First patient

The first patient to have the procedure has requested anonymity.

RECTAL CANCER

Almost 38,000 patients suffer from rectal cancer per year in the UK

Approximately a third of these cancers are within the rectum

Patients often suffer from tenesmus - a painful condition where they find it difficult to empty their bowels and need frequent trips to the toilet

They were given a low dose of heat at 70 degrees.

Doctors say they are planning to treat 50 more patients and they will closely monitor them to discover the most effective temperature at which to perform the procedure.

Unlike radiotherapy, HIFU, can be given to a patient a number of times with minimal risk of toxicity.

The study leader, Professor Paul Abel, from Imperial College Healthcare NHS Trust, said: "There is no incision made during the procedure, it's completely non-invasive, so recovery time will be quicker too.

"As this is the first time this procedure has ever been performed for rectal cancer, we need to study a wider group of patients to assess how effective the treatment is and whether it has the potential to be curative or to lengthen a patient's life."

A spokesman for the charity Beating Bowel Cancer said it welcomes "advances to improve the quality of patients' lives and relieve symptoms".

"As this is a world first, we look forward to further studies and results with more patients over a longer period."

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Turning heat to electricity

donpatent@gmail.com (donpatent) — Fri, 20 Nov 2009 21:06:00 +0000

David L. Chandler, MIT News Office

MIT research points to a much more efficient way of harvesting electrical power from what would otherwise be wasted heat.

In everything from computer processor chips to car engines to electric powerplants, the need to get rid of excess heat creates a major source of inefficiency. But new research points the way to a technology that might make it possible to harvest much of that wasted heat and turn it into usable electricity.

That kind of waste-energy harvesting might, for example, lead to cellphones with double the talk time, laptop computers that can operate twice as long before needing to be plugged in, or power plants that put out more electricity for a given amount of fuel, says Peter Hagelstein, co-author of a paper on the new concept appearing this month in the Journal of Applied Physics.

Hagelstein, an associate professor of electrical engineering at MIT, says existing solid-state devices to convert heat into electricity are not very efficient. The new research, carried out with graduate student Dennis Wu as part of his doctoral thesis, aimed to find how close realistic technology could come to achieving the theoretical limits for the efficiency of such conversion.

Theory says that such energy conversion can never exceed a specific value called the Carnot Limit, based on a 19th-century formula for determining the maximum efficiency that any device can achieve in converting heat into work. But current commercial thermoelectric devices only achieve about one-tenth of that limit, Hagelstein says. In experiments involving a different new technology, thermal diodes, Hagelstein worked with Yan Kucherov, now a consultant for the Naval Research Laboratory, and coworkers to demonstrate efficiency as high as 40 percent of the Carnot Limit. Moreover, the calculations show that this new kind of system could ultimately reach as much as 90 percent of that ceiling.

Hagelstein, Wu and others started from scratch rather than trying to improve the performance of existing devices. They carried out their analysis using a very simple system in which power was generated by a single quantum-dot device — a type of semiconductor in which the electrons and holes, which carry the electrical charges in the device, are very tightly confined in all three dimensions. By controlling all aspects of the device, they hoped to better understand how to design the ideal thermal-to-electric converter.

Hagelstein says that with present systems it’s possible to efficiently convert heat into electricity, but with very little power. It’s also possible to get plenty of electrical power — what is known as high-throughput power — from a less efficient, and therefore larger and more expensive system. “It’s a tradeoff. You either get high efficiency or high throughput,” says Hagelstein. But the team found that using their new system, it would be possible to get both at once, he says.

A key to the improved throughput was reducing the separation between the hot surface and the conversion device. A recent paper by MIT professor Gang Chen reported on an analysis showing that heat transfer could take place between very closely spaced surfaces at a rate that is orders of magnitude higher than predicted by theory. The new report takes that finding a step further, showing how the heat can not only be transferred, but converted into electricity so that it can be harnessed.

A company called MTPV Corp. (for Micron-gap Thermal Photo-Voltaics), founded by Robert DiMatteo SM ’96, MBA ‘06, is already working on the development of “a new technology closely related to the work described in this paper,” Hagelstein says.

DiMatteo says he hopes eventually to commercialize Hagelstein’s new idea. In the meantime, he says the technology now being developed by his company, which he expects to have on the market next year, could produce a tenfold improvement in throughput power over existing photovoltaic devices, while the further advance described in this new paper could make an additional tenfold or greater improvement possible. The work described in this paper “is potentially a major finding,” he says.

DiMatteo says that worldwide, about 60 percent of all the energy produced by burning fuels or generated in powerplants is wasted, mostly as excess heat, and that this technology could “make it possible to reclaim a significant fraction of that wasted energy.”

When this work began around 2002, Hagelstein says, such devices “clearly could not be built. We started this as purely a theoretical exercise.” But developments since then have brought it much closer to reality.

While it may take a few years for the necessary technology for building affordable quantum-dot devices to reach commercialization, Hagelstein says, “there’s no reason, in principle, you couldn’t get another order of magnitude or more” improvement in throughput power, as well as an improvement in efficiency.

“There’s a gold mine in waste heat, if you could convert it,” he says. The first applications are likely to be in high-value systems such as computer chips, he says, but ultimately it could be useful in a wide variety of applications, including cars, planes and boats. “A lot of heat is generated to go places, and a lot is lost. If you could recover that, your transportation technology is going to work better.”

Source

United States Patent 7,390,962
Greiff , et al. June 24, 2008
Micron gap thermal photovoltaic device and method of making the same

Abstract
A method of making a micron gap thermal photovoltaic device wherein at least one standoff is formed on a photovoltaic substrate, a sacrificial layer is deposited on the photovoltaic substrate and about the standoff, an emitter is attached to the standoff and has a lower planar surface separated from the photovoltaic substrate by the sacrificial layer, and the sacrificial layer is removed to form a sub-micron gap between the photovoltaic substrate and the lower planar surface of the emitter.
Inventors: Greiff; Paul (Wayland, MA), DiMatteo; Robert Stephen (Belmont, MA)
Assignee: The Charles Stark Draper Laboratory, Inc. (Cambridge, MA)
Appl. No.: 10/443,414
Filed: May 22, 2003

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Liquid battery big enough for the electric grid?

donpatent@gmail.com (donpatent) — Fri, 20 Nov 2009 18:53:00 +0000

Professor Donald Sadoway’s research in energy storage could help speed the development of renewable energy.

David L. Chandler, MIT News Office

There’s one major drawback to most proposed renewable-energy sources: their variability. The sun doesn’t shine at night, the wind doesn’t always blow, and tides, waves and currents fluctuate. That’s why many researchers have been pursuing ways of storing the power generated by these sources so that it can be used when it’s needed.

So far, those solutions have tended to be too expensive, limited to only certain areas, or difficult to scale up sufficiently to meet the demands. Many researchers are struggling to overcome these limitations, but MIT professor Donald Sadoway has come up with an innovative approach that has garnered significant interest — and some major funding.

The idea is to build an entirely new kind of battery, whose key components would be kept at high temperature so that they would stay entirely in liquid form. The experimental devices currently being tested in Sadoway’s lab work in a way that’s never been attempted in batteries before.

This month, the newly established federal agency ARPA-E (Advanced Research Projects Agency, Energy) announced its first 37 energy-research grants out of a pool of 3,600 applications, and Sadoway’s project to develop utility-scale batteries received one of the largest sums — almost $7 million over five years. And within a few days of the ARPA-E announcement, the French oil company Total — the world’s fifth-largest — announced a $4 million, five-year joint venture with MIT to develop a smaller-scale version of the same technology, suitable for use in individual homes or other buildings.

Because the technology is being patented and could lead to very large-scale commercialization, Sadoway will not discuss the details of the materials being used. But both Sadoway and ARPA-E say the battery is based on low-cost, domestically available liquid metals that have the potential to shatter the cost barrier to large-scale energy storage as part of the nation's energy grid. In announcing its funding of Sadoway’s work, ARPA-E said the battery technology “could revolutionize the way electricity is used and produced on the grid, enabling round-the-clock power from America's wind and solar power resources, increasing the stability of the grid, and making blackouts a thing of the past.”

Andrew Chung, a principal at Lightspeed Venture Partners in Menlo Park, Calif., which has no equity stake in Sadoway’s project at this point, says that “grid-scale storage is an area that’s set to explode in the next decade or so,” and is one that his company is following closely. The liquid battery concept Sadoway is developing “is an exciting approach to solving the problem,” he says.

Big is beautiful

Most battery research, Sadoway says, has been aimed at improving storage for portable or mobile systems such as cellphones, computers and cars. The requirements for such systems, including very low weight and high safety, are very different from the needs of a grid-scale, fixed-location battery system. “What I did was completely ignore the conventional technology used for portable power,” he says. The different set of requirements for stationary systems “opens up a whole new range of possibilities.”

A large, utility-owned system “doesn’t have to be crash-worthy; it doesn’t have to be ‘idiot-proof’ because it won’t be in the hands of the consumer.” And while consumers are willing to pay high prices, pound-for-pound, for the small batteries used in high-value portable devices, the biggest constraint on utility-sized systems is cost. In order to compete with present fossil-fuel power systems, he says, “it has got to be cheap to build, cheap to maintain, last a long time with minimal maintenance, and store enormous amounts of energy.”

And so the new liquid batteries that Sadoway and his team, including graduate student David Bradwell, are designing use low-cost, abundant materials. The basic principle is to place three layers of liquid inside a container: Two different metal alloys, and one layer of a salt. The three materials are chosen so that they have different densities that allow them to separate naturally into three distinct layers, with the salt in the middle separating the two metal layers —like novelty drinks with different layers.

The energy is stored in the liquid metals that want to react with one another but can do so only by transferring ions — electrically charged atoms of one of the metals — across the electrolyte, which results in the flow of electric current out of the battery. When the battery is being charged, some ions migrate through the insulating salt layer to collect at one of the terminals. Then, when the power is being drained from the battery, those ions migrate back through the salt and collect at the opposite terminal.

The whole device is kept at a high temperature, around 700 degrees Celsius, so that the layers remain molten. In the small devices being tested in the lab, maintaining this temperature requires an outside heater, but Sadoway says that in the full-scale version, the electrical current being pumped into, or out of, the battery will be sufficient to maintain that temperature without any outside heat source.

While some previous battery technologies have used one liquid-metal component, this is the first design for an all-liquid battery system, Sadoway says. “Solid components in batteries are speed bumps. When you want ultra-high current, you don’t want any solids.”

Inspiration from aluminum

The initial inspiration for the idea came from thinking about a very different technology, Sadoway says: one of the biggest users of electrical energy, aluminum smelting plants. Sadoway realized that this was one of the few existing examples of a system that could sustain extremely high levels of electrical current over a sustained period of years at a time. “It’s an electrochemical process that runs at high temperatures, and at a current of hundreds of thousands of amps,” he says. In a sense, the new concept is like an aluminum plant running in reverse, producing power instead of consuming it.

Chung says that from the point of view of a venture capitalist, the research is particularly intriguing for several reasons. Not only does it offer the potential to significantly lower the cost and increase cycle life [the number of times it can be charged and discharged] of large-scale electricity storage, but it also suggests that the risk typically associated with an early stage research project may be lower because the system draws on decades of experience in the design and operation of aluminum production facilities. “That gives us added confidence that some of the targets around cost, scalability and safety have merit,” he says.

The team is now testing a number of different variations of the exact composition of the materials in the three layers, and of the design of the overall device. Sadoway says that thanks to initial funding through the Deshpande Center and the Chesonis Family Foundation, he and his team were able to develop the concept to the point of demonstrating a proof-of-principle at the laboratory scale. That, in turn, made it possible to get the large grants to develop the technology further.

“It’s an example of work that sprang from basic science, was developed to a pilot scale, and now is being scaled up to have a real transformational impact in the world,” says Ernest Moniz, director of the MIT Energy Initiative.

The laboratory tests have provided “some measure of confidence,” Sadoway says. But many more tests will be needed to “demonstrate that the idea is scalable to industrial size, at competitive cost.” But while he is very confident that it will all work, there are a lot of unknowns, he says, including how to design and build the necessary containers, electrical control systems, and connections.

“We’re talking about batteries of a size never seen before,” he says. And the system they develop has to include everything, including control systems and charger electronics on an unprecedented scale.

For Sadoway, the project is worth pursuing despite its daunting challenges, because the potential impact is so great. “I’m not doing this because I want another journal publication,” Sadoway says. “It’s about making a difference … It’s an opportunity to invent our way out of the energy problem.”

Source

Nanotube defects equal better energy and storage systems

donpatent@gmail.com (donpatent) — Thu, 19 Nov 2009 21:27:00 +0000

November 19, 2009

Mark Hoefer (left), a UCSD materials science grad student, and mechanical

engineering professor Prabhakar Bandaru have discovered that defects in carbon

nanotubes could lead to supercapacitors that could possibly be used for portable

electronic devices such as cell phones.

Carbon nanotubes could serve as supercapacitor electrodes with enhanced charge and energy storage capacity

(inset: a magnified view of a single carbon nanotube). Credit: UC San Diego

(PhysOrg.com) -- Most people would like to be able to charge their cell phones and other personal electronics quickly and not too often. A recent discovery made by UC San Diego engineers could lead to carbon nanotube-based supercapacitors that could do just this.

In recent research, published in Applied Physics Letters, Prabhakar Bandaru, a professor in the UCSD Department of Mechanical and Aerospace Engineering, along with graduate student Mark Hoefer, have found that artificially introduced defects in nanotubes can aid the development of supercapacitors.

"While batteries have large storage capacity, they take a long time to charge; while electrostatic capacitors can charge quickly but typically have limited capacity. However, supercapacitors/electrochemical capacitors incorporate the advantages of both," Bandaru said.

Carbon nanotubes (CNTs) have been generally hailed as one of the wonder materials of the 21st century and have been widely recognized as ushering in the nanotechnology revolution. They are cylindrical structures, with diameters of 1 to 100 nanometers, that have been suggested to have outstanding structural, chemical, and electrical, characteristics based on their atomically perfect structures with a large surface area-to-volume ratio. However, defects are inevitable in such a practical structure, an aspect that was first investigated by UCSD engineering graduate student Jeff Nichols and then substantially extended by Hoefer in Bandaru's lab.

"We first realized that defective CNTs could be used for energy storage when we were investigating their use as electrodes for chemical sensors," Hoefer said. "During our initial tests we noticed that we were able to create charged defects that could be used to increase CNT charge storage capabilities."

Specifically, defects on nanotubes create additional charge sites enhancing the stored charge. The researchers have also discovered methods which could increase or decrease the charge associated with the defects by bombarding the CNTs with argon or hydrogen.

"It is important to control this process carefully as too many defects can deteriorate the electrical conductivity, which is the reason for the use of CNTs in the first place. Good conductivity helps in efficient charge transport and increases the power density of these devices," Bandaru added.

"At the very outset, it is interesting that CNTs, which are nominally considered perfect, could be useful with so many incorporated defects," he added.

The researchers think that the energy density and power density obtained through their work could be practically higher than existing capacitor configurations which suffer from problems associated with poor reliability, cost, and poor electrical characteristics.

Bandaru and Hoefer hope that their research could have major implications in the area of energy storage, a pertinent topic of today. "We hope that our research will spark future interest in utilizing CNTs as electrodes in charge storage devices with greater energy and power densities," Hoefer said.

While more research still needs to be done to figure out potential applications from this discovery, the engineers suggest that this research could lead to wide variety of commercial applications, and hope that more scientists and engineers will be compelled to work in this area, Bandaru said.

Meanwhile, Hoefer said this type of research will help fuel his future engineering career.

"It is remarkable how current tools and devices are becoming increasing more efficient and yet smaller due to discoveries made at the nanoscale," he said. "My time spent investigating CNTs and their potential uses at the Jacobs School will prepare me for my career, since future research will continue the trend of miniaturization while increasing efficiency."

More information: “Determination and enhancement of the capacitance contributions in carbon nanotube based electrode systems,” Applied Physics Letters. M. Hoefer and P.R. Bandaru.

Source: University of California - San Diego

Source

Nanotechnology Team Captures Tumor Cells in Bloodstream

donpatent@gmail.com (donpatent) — Wed, 18 Nov 2009 19:23:00 +0000

Vladimir Zharov's team of researchers has discovered a way to capture tumor cells in the bloodstream.

Nov. 17, 2009

A team led by University of Arkansas for Medical Sciences (UAMS) researchers on the cutting edge of nanotechnology has found a way to capture tumor cells in the bloodstream that could dramatically improve earlier cancer diagnosis and prevent deadly metastasis.

The discovery was published Nov. 15 in Nature Nanotechnology, a prestigious monthly print and online journal that provides a forum for leading research papers in all areas of nanoscience and nanotechnology. To read the abstract, click here.

Vladimir Zharov, director of the Phillips Classic Laser and Nanomedicine Laboratory at UAMS, said his team of researchers can inject a cocktail of magnetic and gold nanoparticles with a special biological coating into the bloodstream to target circulating tumor cells. A magnet attached to the skin above peripheral blood vessels can then capture the cells.

“By magnetically collecting most of the tumor cells from blood circulating in vessels throughout the whole body, this new method can potentially increase specificity and sensitivity up to 1,000 times compared to existing technology,” Zharov said.

Once the tumor cells are targeted and captured by the magnet, they can either be microsurgically removed from vessels for further genetic analysis or can be noninvasively eradicated directly in blood vessels by laser irradiation through the skin that is still safe for normal blood cells.

Zharov’s team, which has recently been awarded more than $3.7 million in clinical nanomedicine-related grants, includes Ekaterina Galanzha, M.D., Ph.D., an assistant professor in the UAMS Department of Otolaryngology; Evgeny Shashkov, Ph.D., a visiting scholar and laser physicist; Thomas Kelly, Ph.D., associate professor in the UAMS Department of Pathology; Jin-Woo Kim, Ph.D., a nano-biotechnologist at the University of Arkansas at Fayetteville; and Lily Yang, Ph.D., a biologist from Emory University.

A second related discovery by Zharov’s team was published in Cancer Research in October. It demonstrated that periodic laser irradiation of blood vessels decreases the level of circulating metastatic tumor cells more than 10 times and eventually led to an interruption of metastasis development in distant organs. To read the abstract, click here.

“Further study could determine whether these new cancer treatments are effective enough to be used alone or if they should be used in conjunction with conventional cancer therapy,” Zharov said.

The discovery highlighted in Cancer Research earned Zharov and his team a selection for Faculty of 1000 Biology, an award-winning Web site that highlights and evaluates the most interesting papers published in the biological sciences. Papers are selected based on the recommendations of more than 2000 of the world’s top researchers.

The new discoveries can also be applied for early detection of cancer recurrence and for real-time monitoring therapy efficiency involving the counting of circulating tumor cells.

“Most cancer deaths are the result of metastasis due to the spread of tumor cells from the primary tumor through the blood,” said James Suen, M.D., chairman of the UAMS Winthrop P. Rockefeller Cancer Institute’s Department of Otolaryngology, Head and Neck Surgery. “This revolutionary discovery introduced by Zharov’s team gives many patients hope in earlier cancer diagnosis and better treatment. The nanomedicine-based approach to read and treat whole blood in the body with nanotechnology seems to be universal, with further development holding the promise for the diagnosis and treatment of many diseases, including infections or cardiovascular disorders to prevent stroke and heart attack.”

UAMS is the state’s only comprehensive academic health center, with five colleges, a graduate school, a new 540,000-square-foot hospital, six centers of excellence and a statewide network of regional centers. UAMS has 2,775 students and 748 medical residents. Its centers of excellence include the Winthrop P. Rockefeller Cancer Institute, the Jackson T. Stephens Spine & Neurosciences Institute, the Myeloma Institute for Research and Therapy, the Harvey & Bernice Jones Eye Institute, the Psychiatric Research Institute and the Donald W. Reynolds Institute on Aging. It is the state’s largest public employer with more than 10,000 employees, including nearly 1,150 physicians who provide medical care to patients at UAMS, Arkansas Children’s Hospital, the VA Medical Center and UAMS’ Area Health Education Centers throughout the state. Visit www.uams.edu or www.uamshealth.com.

Source

Curry as Cure? Spicing Up the Effectiveness of a Potential Disease-Fighter

donpatent@gmail.com (donpatent) — Mon, 16 Nov 2009 16:30:00 +0000

ScienceDaily (Nov. 16, 2009) — Scientists are reporting development of a nano-size capsule that boosts the body's uptake of curcumin, an ingredient in yellow curry now being evaluated in clinical trials for treatment of several diseases.

Their study is in ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication.

Yellow curry contains curcumin, a promising disease-fighter. Scientists developed nano-sized capsules containing the curry ingredient in an effort to improve its absorption and effectiveness in the body. (Credit: Wikimedia Commons)

Koji Wada and colleagues note that curcumin is a potent antioxidant found in the spice, turmeric. Clinical trials are checking its safety and effectiveness for colon cancer, psoriasis, and Alzheimer's disease. However, digestive juice in the gastrointestinal tract quickly destroys curcumin so that little actually gets into the blood.

Scientists have known for years that encapsulating insulin and certain other drugs into structures called liposomes can boost absorption. The scientists prepared the liposomes encapsulating curcumin and fed them to laboratory rats.

Encapsulating more than quadrupled absorption of curcumin, and also boosted antioxidant levels in the blood. The encapsulating process could be an answer to the problem of increasing curcumin's absorption in the digestive environment of the gastrointestinal tract, they suggest.

Source

Remote-controlled nanocomposite for on-demand drug delivery inside the body

donpatent@gmail.com (donpatent) — Mon, 16 Nov 2009 16:02:00 +0000

Posted: November 16, 2009

(Nanowerk Spotlight) Quite a number of serious medical conditions, such as cancer, diabetes and chronic pain, require medications that cannot be taken orally, but must be dosed intermittently, on an as-needed basis, and over a long period of time. Researchers have been trying to develop drug delivery techniques with 'on-off switches' that would allow controlled release of drugs into the body. These methods use stimuli such as an implanted heat source or an implanted electronic chip to trigger the drug release from the implanted reservoir. So far, none of these methods can reliably perform all the needed actions: repeatedly turn dosing on and off, deliver consistent doses, and adjust doses according to each patient's need.
By combining magnetism with nanotechnology, researchers have now created a small implantable device that encapsulates the drug in a specially engineered membrane, embedded with magnetic iron oxide nanoparticles. The application of an external, alternating magnetic field heats the magnetic nanoparticles, causing the gels in the membrane to warm and temporarily collapse. This collapse opens up pores that allow the drug to pass through and into the body. When the magnetic field is turned off, the membranes cool and the gels re-expand, closing the pores and halting drug delivery. No implanted electronics are required.
"We have developed an implantable system that can provide on-demand, reproducible drug release whenever the patient – or other operator – wants, for as long as needed, and with the intensity that is desired, using a trigger that is external to the body – in this case an oscillating magnetic field," Daniel Kohane tells Nanowerk. "Most of the previously designed systems could only result in a single release event, or involved implanted triggering systems, or connectors to the outside world."
Kohane, an associate professor of anesthesiology at Harvard Medical School and a senior associate in critical care medicine at Children's Hospital Boston, and his team have reported their findings in a recent issue of Nano Letters ("A Magnetically Triggered Composite Membrane for On-Demand Drug Delivery").
Kohane explains that composite membrane-based drug delivery devices have the potential to greatly increase the flexibility of pharmacotherapy and improve the quality of patients' lives by providing repeated, long-term, on-demand drug delivery for a variety of medical applications, including the treatment of pain (local or systemic anesthetic delivery), local chemotherapy, and insulin delivery.
The membrane that Kohane's team developed consists of ethyl cellulose (the membrane support), superparamagnetic magnetite nanoparticles (the triggering entity), and thermosensitive poly(N-isopropylacrylamide) (PNIPAM)-based nanogels (the switching entity). Membranes were prepared by co-evaporation so that the nanogel and magnetite nanoparticles were entrapped in ethyl cellulose to form a presumably disordered network. To facilitate effective in vivo triggering, the nanogels were engineered to remain swollen (i.e., in the 'off' state) at body temperature.

Stimulus-responsive membrane triggering in vitro: schema of the proposed mechanism of membrane function. (Reprinted with permission from American Chemical Society)
"When we subjected the magnetic nanoparticles embedded in the membrane to an external oscillating magnetic field, they heated inductively," explains Kohane. "The heat generated by magnetite induction heating was transferred to the adjacent thermosensitive nanogels, causing the nanogels to shrink and permit drug diffusion out of the device. When we turned off the magnetic field, the nanogels cooled, causing them to reswell, turning off the drug flow and refilling the membrane pores."
The researchers observed a 10- to 20-fold differential flux between the 'off' and 'on' states. Furthermore, multiple on-off cycles could be performed without significantly changing the permeability of the membrane in the off state.
The on-off action doesn't occur immediately but was much more rapid than that seen with bulk, interpenetrating hydrogel networks. The devices turned 'on' with only a 1-2 minute time lag after the solution temperature reached 40°C and turned 'off' with a 5-10 minute lag after the stimulus was switched off.
Kohane points out that reproducibility will clearly be a key consideration in devices of this type, especially with drugs with narrow therapeutic indices.
"We have shown excellent reproducibility over four magnetically induced cycles" he says. "The maximum number of cycles over which that reproducibility can be maintained remains to be determined, as does the number of cycles over which it needs to be maintained. The latter will depend to a large extent on the specific clinical indication and the expected duration of therapy. Some devices might only need to be triggered a few times, while others – e.g., for a chronic condition requiring treatment several times a day – might require reproducible triggering over thousands of cycles. This issue will be of great importance in the downstream development of the device. Indeed, the ultimate design of a clinical drug delivery device based on this membrane technology, including the specific materials of which it will be composed, is yet to be determined."
By Michael Berger. Copyright 2009 Nanowerk LLC

Source

Picking up night waves

donpatent@gmail.com (donpatent) — Tue, 10 Nov 2009 13:00:00 +0000

Published: 10 November 2009 07:00 AM
Source: The Engineer

Future solar cells could operate 24 hours a day by collecting radiation emitted from the Earth at night and turning it into energy.

So believe researchers at Manchester University's School of Electronic and Electrical Engineering, who are working on a new technology that would give solar cells the ability to collect light energy from multiple wavelengths.

The team has developed nano-diodes that detect terahertz waves lying at the far end of the infrared band, right before microwaves.

Project leader Aimin Song, a professor of nanoelectronics at Manchester University, said their nano-diode terahertz detector has a novel planar architecture and works at 1.5THz or 1,500GHz, the highest speed of electronic nano-devices to date.

He claimed that combining such a diode with an antenna would make it possible to collect energy from infrared waves and convert them into DC electricity.

Song said the technology would take advantage of the Earth's greenhouse effect.

'The Earth and the atmosphere absorb a lot of the sunlight,' he added. 'After absorption they slowly radiate this energy back but not in the visible light frequency range but in the infrared frequency band.'

Song said that the technology, which is known as rectenna because it combines a rectifier (diode) and antenna, has already been demonstrated to work for converting microwave energy into DC electricity with a claimed efficiency between 80 and 90 per cent. 'If we develop this rectenna technology for the infrared frequency band, we can develop solar cells that operate at night time,' he said. 'This rectenna concept could potentially offer solar cells 80-90 per cent efficiency.'

Manchester University recently began a one-year commercialisation programme for the technology and Song said a spin-out company could be formed within the first half of 2010.

'We hope at the end of this one-year programme to achieve the first prototype device to work at infrared frequencies,' he said. 'Our first prototype wouldn't work for visible sunlight, but it would work to harvest energy in the night.'

Manchester University is also involved in a three-year EU-funded project beginning in January that will attempt to develop nano-devices that can both detect and emit terahertz waves.

Siobhan Wagner

Source

Findings show nanomedicine promising for treating spinal cord injuries

donpatent@gmail.com (donpatent) — Mon, 09 Nov 2009 04:15:00 +0000

November 8, 2009
This image represents "copolymer micelles," tiny drug-delivery spheres that could be used in a new approach for repairing damaged nerve fibers in spinal cord injuries. The bottom graphs show data indicating damaged spinal cord tissue recovered its "action potential," or ability to transmit signals, after treatment with the micelles. (Purdue University's Weldon School of Biomedical Engineering)

Enlarge

(PhysOrg.com) -- Researchers at Purdue University have discovered a new approach for repairing damaged nerve fibers in spinal cord injuries using nano-spheres that could be injected into the blood shortly after an accident.

The synthetic "copolymer micelles" are drug-delivery spheres about 60 nanometers in diameter, or roughly 100 times smaller than the diameter of a red blood cell.

Researchers have been studying how to deliver drugs for cancer treatment and other therapies using these spheres. Medications might be harbored in the cores and ferried to diseased or damaged tissue.

Purdue researchers have now shown that the micelles themselves repair damaged axons, fibers that transmit electrical impulses in the spinal cord.

"That was a very surprising discovery," said Ji-Xin Cheng, an associate professor in the Weldon School of Biomedical Engineering and Department of Chemistry. "Micelles have been used for 30 years as drug-delivery vehicles in research, but no one has ever used them directly as a medicine." [NanoViricides uses polymer micelles as a viricide for H1N1, HIV and numerous other viruses!]

Findings are detailed in a research paper appearing Sunday (Nov. 8) in the journal Nature Nanotechnology. [ http://www.nature.com/nnano/journal/vaop/ncurrent/abs/nnano.2009.303.html ]

A critical feature of micelles is that they combine two types of polymers, one being hydrophobic and the other hydrophilic, meaning they are either unable or able to mix with water. The hydrophobic core can be loaded with drugs to treat disease.

The micelles might be used instead of more conventional "membrane sealing agents," including polyethylene glycol, which makes up the outer shell of the micelles. Because of the nanoscale size and the polyethylene glycol shell of the micelles, they are not quickly filtered by the kidney or captured by the liver, enabling them to remain in the bloodstream long enough to circulate to damaged tissues.

In research led by biomedical engineering doctoral student Yunzhou Shi, the micelles also were shown to be non-toxic at the concentrations required.

"With the micelles, you need only about 1/100,000th the concentration of regular polyethylene glycol," Cheng said.

Ongoing research at Purdue has shown the benefits of polyethylene glycol, or PEG, to treat animals with spinal cord injuries. The work is led by Richard Borgens, director of the Center for Paralysis Research and the Mari Hulman George Professor of Neurology in the School of Veterinary Medicine.

Findings have shown that PEG specifically targets damaged cells and seals the injured area, reducing further damage. It also helps restore cell function.

The new findings were made possible by the interdisciplinary nature of the work, which involves Borgens and other Purdue researchers, Cheng said. The collaboration included Borgens; Riyi Shi, an associate professor of biomedical engineering and basic medical sciences; and Kinam Park, Showalter Distinguished Professor of Biomedical Engineering and a professor of pharmaceutics.

Findings showed that cores made of particular materials work better than others at restoring function to damaged axons, which are slender extensions of nerve cells.

The research also showed that without the micelles treatment about 18 percent of axons recover in a segment of damaged spinal cord tested in a "double sucrose gap recording chamber." The micelles treatment boosted the axon recovery to about 60 percent. The researchers used the chamber to study how well micelles repaired damaged nerve cells by measuring the "compound action potential," or the ability of a spinal cord to transmit signals.

The experiment mimics what happens during a traumatic spinal cord injury. Findings showed that micelles might be used to repair axon membranes damaged by compression injuries, a common type of spine injury.

The researchers also tracked dyed micelles in rats, demonstrating that the nanoparticles were successfully delivered to injury sites. Findings also showed micelles-treated animals recovered the coordinated control of all four limbs, whereas animals treated with conventional polyethylene glycol did not.

Source: Purdue University

Source

Carbon Nanotube Sponges

donpatent@gmail.com (donpatent) — Fri, 06 Nov 2009 18:32:00 +0000

Scientists have invented a carbon-based sponge that can soak up organic pollutants, such as oils and solvents, from the surface of water. No water is absorbed and the sponge can then be wrung out and reused, like an ordinary household sponge. Absorbing up to 180 times its own weight in organic matter, the sponge is light and tough and has the potential to dramatically enhance oil spill cleanup.

Professors Anyuan Cao (Peking University) and Dehai Wu (Tsinghua University), who are publishing their breakthrough in Advanced Materials, say “the sponges have new properties that integrate the merits of fragile aerogels with their high surface area [the lowest density solid material known is an aerogel], and conventional soft materials with their robustness and flexibility.”

Current commercial absorbents for oil spill recovery and industrial use tend to be based on cellulose or polypropylene. These materials can absorb only up to 20 times their own weight and are impractical for large spills, where dispersants are used. Dispersants allow the oil to become diluted, but it remains in the water. Other materials based on porous oxide-based materials or other polymers can absorb up to twice as much pollutant per weight, but generally need to be heated to remove the organic material. High-temperature heating is not practical on small scales or on ships, and a clear advantage of a squeezable sponge is that the oil can be readily recovered and reused. For other applications including solvent cleanup, the sponges can be heated to remove the pollutant, without affecting the properties of the sponges.

Cao and Wu’s sponges are made from interconnected carbon nanotubes– tiny, strong and hollow cylinders of interconnected carbon atoms. In this instance the tubes are 30–50 nanometres across and tens to hundreds of micrometers long (a nanometre is 10–9 metres, or one millionth of a millimetre; a micrometre is 1000 times as long). The surface of the tubes is naturally hydrophobic (water-hating), therefore no further modification is needed for the sponges to repel water. At the same time, they love to absorb oil on their surface. As the sponges are over 99% porous or empty, they float on water and there is a lot of room for oil to be absorbed, leading to the extremely high capacity for retention – for example, 143 times the sponge’s weight for diesel oil and 175 for ethylene glycol.

Lateral thinking was the key to the scientists’ breakthrough. A major ambition among carbon nanotube researchers is to look for ways to make large lined-up arrays of the tubes. Cao and Wu, however, searched for a method that would make long tubes that were completely disordered. This randomness allows the tubes to slide past each other, allowing the sponge to be manually reduced in size by 95%, and bent or twisted without breaking. As the sponge is squeezed, any oil or solvent in the cavities and on the surface of the tubes is expelled. To gain the best effect, the sponges first have to be filled with solvent and then compressed gently in a process called densification, but after this they are extremely robust and can be used potentially thousands of times. They swell to recover their original dimensions when exposed to oil or solvent and “a small densified pellet of sponge can quickly remove a spreading diesel oil film with an area up to 800 times that of the sponge”, as illustrated in the accompanying figure. This effect occurs even if the sponge is placed at the edge of the spill.

Potential applications reach beyond oil spill recovery. According to Cao, “the nanotube sponges can be used as filters, membranes, or absorbents to remove bacteria or contaminants from liquid or gas. They could also be used as noise-absorption layers in houses, and soldiers might benefit by using these sponges in impact energy absorbing components while adding little weight. Thermally insulated clothing is also possible.” Large-scale production is currently being investigated.

A. Cao et al., Adv. Mater. ; DOI: 10.1002/adma.200902986

Source

Golden Nanocages Could Deliver Cancer Drugs to Tumors

donpatent@gmail.com (donpatent) — Tue, 03 Nov 2009 21:52:00 +0000

November 3rd, 2009 4:10 PM

Cancer treatment in the future could have dramatically reduced side effects if new nanotechnology research proves useful. Heat-sensitive nanoparticles might be able to deliver drugs to a targeted location in the body—to a tumor, say—and release them on cue, a sought-after goal of biomedical research.

One research team has developed nanoparticle cages that can be stuffed with tiny amounts of drugs that are only released on demand.

These “nanocages” are cubes of gold, with sides about 50-billionths of a meter long and holes at each corner.

They are easily made, using silver particles as a mold, and then coated with strands of a smart polymer. The polymer strands are normally extended and bushy and cover the holes in the cube. But when heated the strands collapse, leaving the holes open and allowing the drug inside to escape [The New York Times]. The researchers say they can engineer the nanocages to stick to tumors.

Doctors could release the packaged drugs whenever they want, just by zapping the cages inside the patient’s body with near-infrared light. Near-infrared wavelengths are not greatly absorbed by body tissues, so light from a near-infrared laser could penetrate a couple of inches inside the body, but they are absorbed by gold [The New York Times]. Researchers could design the cages to fall apart at just a few degrees above normal body temperature, so they only spill their contents where the heat is applied; they could also alter the drug’s rate of release by adjusting the laser’s intensity. The technology, described in the journal Nature Materials, could help cut down on the side effects of today’s treatments which are often caused by toxic drugs coursing through the body.

Source

Closest Look Ever at Graphene

donpatent@gmail.com (donpatent) — Sat, 31 Oct 2009 15:31:00 +0000

10/31/2009 2:15:29 AM
Closest Look Ever at Graphene: Stunning Images of Individual Carbon Atoms From TEAM 0.5 microscope

Source

Next-generation carbon nanotube microcapsules deliver 'chemicals on demand'

donpatent@gmail.com (donpatent) — Fri, 30 Oct 2009 18:25:00 +0000

Posted: October 28, 2009
Next-generation carbon nanotube microcapsules deliver 'chemicals on demand'
(Nanowerk News) Scientists in California are reporting development of a new generation of the microcapsules used in carbon-free copy paper, in which capsules burst and release ink with pressure from a pen. The new microcapsules burst when exposed to light, releasing their contents in ways that could have wide-ranging commercial uses from home and personal care to medicine. Their study appears in the Journal of the American Chemical Society, a weekly publication ("Chemicals On Demand with Phototriggerable Microcapsules").

A new generation of microcapsules, shown above, promise to deliver "chemicals on demand" for a wide range of uses, including medicine and personal care.
Jean Fréchet, Alex Zettl and colleagues note that liquid-filled microcapsules have many other uses, including self-healing plastics. Those plastics contain one group of microscapsules filled with monomer and another with a catalyst. When scratches rip open the capsules, the contents flow, mix, and form a seal. Microcapsules that burst open when exposed to light would have great advantages, the scientists say. Light could be focused to a pinpoint to kill cancer cells, for instance, or shined over an large area to print a pattern.
The new microcapsules consist of nylon spheres about the size of a grain of sand. They enclose a liquid chemical sprinkled with carbon nanotubes. The nanotubes convert laser light to heat that bursts the nylon capsule, releasing the chemical. Using such a system, doctors, for example, might inject microcapsules containing anti-cancer drugs to specific cells and make the capsules burst upon exposure to laser light, delivering their contents precisely where and when they are needed in the body.

Source: American Chemical Society

Source

Hard Rain: Pitt-led Researchers Create Nano-Particle Coating to Prevent Freezing Rain Buildup on Roads, Power Lines

donpatent@gmail.com (donpatent) — Fri, 30 Oct 2009 17:32:00 +0000

October 29, 2009
Contact: Morgan Kelly
412-624-4356 (office);
412-897-1400 (cell)
mekelly@pitt.edu

Hard Rain: Pitt-led Researchers Create Nano-Particle Coating to Prevent Freezing Rain Buildup on Roads, Power Lines

Inspired by water-resistant lotus leaves, the Pitt-developed solution repels freezing rain and provides the first evidence of anti-icing ability in superhydrophobic coatings, team reports in “Langmuir”

PITTSBURGH-Preventing the havoc wrought when freezing rain collects on roads, power lines, and aircrafts could be only a few nanometers away. A University of Pittsburgh-led team demonstrates in the Nov. 3 edition of “Langmuir” a nanoparticle-based coating developed in the lab of Di Gao, a chemical and petroleum engineering professor in Pitt's Swanson School of Engineering, that thwarts the buildup of ice on solid surfaces and can be easily applied.

The paper, by lead author and Pitt doctoral student Liangliang Cao, presents the first evidence of anti-icing properties for a burgeoning class of water repellants-including the Pitt coating-known as superhydrophobic coatings. These thin films mimic the rutted surface of lotus leaves by creating microscopic ridges that reduce the surface area to which water can adhere. But the authors note that because ice behaves differently than water, the ability to repulse water cannot be readily applied to ice inhibition. Cao's coauthors include Gao, Jianzhong Wu, a chemical engineering professor at the University of California at Riverside, and Andrew Jones and Vinod Sikka of Ross Technology Corporation of Leola, Pa.

The team found that superhydrophobic coatings must be specifically formulated to ward off ice buildup. Gao and his team created different batches made of a silicone resin-solution combined with nanoparticles of silica ranging in size from 20 nanometers to 20 micrometers, at the largest. They applied each variant to aluminum plates then exposed the plates to supercooled water (-20 degrees Celsius) to simulate freezing rain.

Cao writes in “Langmuir” that while each compound containing silica bits of 10-or-fewer micrometers deflected water, only those with silica pieces less than 50 nanometers in size completely prevented icing. The minute surface area of the smaller fragments means they make minimal contact with the water. Instead, the water mostly touches the air pockets between the particles and falls away without freezing. Though not all superhydrophobic coatings follow the Pitt recipe, the researchers conclude that every type will have a different particle-scale for repelling ice than for repelling water.

Gao tested the coating with 50-nanometer particles outdoors in freezing rain to determine its real-world potential. He painted one side of an aluminum plate and left the other side untreated. The treated side had very little ice, while the untreated side was completely covered. He produced similar results on a commercial satellite dish where the glossed half of the dish had no ice and the other half was encrusted.

A video available on Pitt's Web site shows an aluminum plate glazed with Gao's superhydrophobic coating (left) repelling the supercooled water. For the uncoated plate (right), the water freezes on contact and ice accumulates. The video can be accessed at www.pitt.edu/news2009/ice.html

Related links:Langmuir paper Gao video

Source

Nanoparticle Self-Lighting Photodynamic Therapy For Cancer Treatment

donpatent@gmail.com (donpatent) — Thu, 29 Oct 2009 15:28:00 +0000

Nanoparticle Self-Lighting Photodynamic Therapy For Cancer Treatment

Wei Chen^*

Department of Physics, University of Texas at Arlington, Arlington, TX 76019-0059

Photodynamic therapy (PDT) has been designated as a “promising new modality in the treatment of cancer” since the early 1980s. Light must be delivered in order to activate photodynamic therapy. Most photosensitizers have strong absorption in the ultraviolet (UV) – blue range, therefore, UV -blue light is needed for their activation. Unfortunately, UV-blue light has minimal penetration into tissue and its application for in vivo activation is a problem. To solve the problem and to enhance the PDT treatment for deep cancers, we introduce a new PDT system in which the light is generated by afterglow nanoparticles with attached photosensitizers. When the nanoparticle-photosensitizer conjugates are targeted to tumor, the light from afterglow nanoparticles will activate the photosensitizers for photodynamic therapy. Therefore, no external light is required for treatment. More importantly, it can be used to treat deep tumor such as breast cancer because the light source is attached to the photosensitizers and are delivered to the tumor cells all together. This new modality is refereed as Nanoparticle Self-Lighting Photodynamic Therapy (NSLPDT).

Key Words: Photodynamic Therapy, Cancer, Nanoparticles, Quantum Dots, Luminescence, Afterglow, Penetration, Radiation Therapy.

Corresponding Author: weichen@uta.edu

Source

Sonnemed Patent Filing

donpatent@gmail.com (donpatent) — Sat, 24 Oct 2009 13:42:00 +0000

(WO/2009/129321) COMPOUNDS AND METHODS FOR ACTIVATED THERAPY

Pub. No.:

WO/2009/129321

Publication Date: 22.10.2009
International Application No.: PCT/US2009/040688
International Filing Date: 15.04.2009

Applicants:
SONNEMED LLC [US/US]; 10 Mt. Vernon Street, #208 Winchester, MA 01890 (US) (All Except US).
LEWIS, Thomas [US/US]; (US) (US Only).
SZULWACH, Ann, M. [US/US]; (US) (US Only).

Inventors:
BURKE, Donald; .
LEWIS, Thomas; (US).

Title:
COMPOUNDS AND METHODS FOR ACTIVATED THERAPY

Abstract:
Provided herein are compounds for detection, diagnosis and treatment of target tissues or target compositions, including hyperproliferative tissues such as tumors, using sonodynamic and/or photodynamic methods. In particular, photosensitizer and/or sonosensitizer compounds that collect in hyperproliferative tissue are provided.

Description
[Snips]
The compounds of the invention are useful as sonosensitizers, photosensitizers and/or as dual acting sensitizers as therapeutic and diagnostic agents, for example for treatment of several cancer types such as, but not limited to, melanoma, prostate, brain, colon, ovarian, breast, skin, lung, esophagus and bladder cancers and other hormone-sensitive tumors, as well as for treatment of age-related macular degeneration, and for killing cells, viruses, fungi and bacteria in samples and living tissues as well known in the art of PDT and other sonosensitizer applications.
....

The invention further relates to a method of sonodynamic therapy, which comprises administering to an individual in need an effective amount of a compound of the invention, followed by local ultrasound. The compounds of the invention are also useful for photo- and sonodestruction of normal or malignant animal cells, as desired, as well as of microorganisms in culture, enabling selective photo- and sonodestruction of certain types of cells in culture or infective agents. Thus, the invention further provides the use of the compounds of the invention for in vivo, ex-vivo or in vitro killing of cells or infectious agents such as bacteria, viruses, parasites and fungi in a biological product, e.g. blood, which comprises treating the infected sample with the compound of the invention followed by ultrasound of the sample. Examples of such diseases or conditions include acne, Aids, viral hepatitis, diabetic retinopathy, infection with sars virus, coronary artery stenosis, carotid artery stenosis, intermittent claudication, or Asian (chicken) flu virus, or infections caused by intracellular infectious agents such as Clamidia, tox, ricetzia, rocky mountain spotted fever, q-fever, and others.

Source

Posted by donpatent at 2:24 PM

Growing Cartilage From Stem Cells

donpatent@gmail.com (donpatent) — Thu, 22 Oct 2009 21:38:00 +0000

Article Date: 22 Oct 2009 - 6:00 PDT

Damaged knee joints might one day be repaired with cartilage grown from stem cells in a laboratory, based on research by Professor Kyriacos Athanasiou, chair of the UC Davis Department of Biomedical Engineering and his colleagues.

Using adult stem cells from bone marrow and skin as well as human embryonic stem cells, Athanasiou and his group have already grown cartilage tissue in the lab. Now they are experimenting with various chemical and mechanical stimuli to improve its properties.

Cartilage is one of the very rare tissues that lacks the ability to heal itself. When damaged by injury or osteoarthritis, the effects can be long-lasting and devastating.

"If I cut a tiny line on articular cartilage (the cartilage that covers the surfaces of bones at joints), it will never be erased," Athanasiou said. "It's like writing on the moon. If I go back to look at it a year later, it will look exactly the same."

Work that Athanasiou's group began in the early 1990s at Rice University has resulted in the only FDA-approved products for treatment of small lesions on articular cartilage. (In total, Athanaisou's patents have resulted in 15 FDA-approved products.)

"This will be live, biological cartilage that will not only fill defects, but will potentially be able to resurface the entire surface of joints that have been destroyed by osteoarthritis," Athanasiou said. Currently, joint replacements using metal and plastic prosthetics are the only recourse for the one in five adults who will suffer major joint damage from osteoarthritis.

Source:
Andy Fell
University of California - Davis

Source

Nanomagnets Guide Stem Cells To Damaged Tissue

donpatent@gmail.com (donpatent) — Thu, 22 Oct 2009 21:18:00 +0000

ScienceDaily (Oct. 22, 2009)

Microscopic magnetic particles have been used to bring stem cells to sites of cardiovascular injury in a new method designed to increase the capacity of cells to repair damaged tissue, UCL scientists have announced.

The cross disciplinary research, published in The Journal of the American College of Cardiology: Cardiovascular Interventions, demonstrates a technique where endothelial progenitor cells – a type of stem cell shown to be important in vascular healing processes – have been magnetically tagged with a tiny iron-containing clinical agent, then successfully targeted to a site of arterial injury using a magnet positioned outside the body.

Following magnetic targeting, there was a five-fold increase in cell localisation at a site of vascular injury in rats. The team also demonstrated a six-fold increase in cell capture in an in vitro flow system (where microscopic particles are suspended in a stream of fluid and examined to see how they behave).

Although magnetic fields have been used to guide cellular therapies, this is the first time cells have been targeted using a method directly applicable to clinical practice. The technique uses an FDA (U.S. Food and Drug Administration) approved agent that is already used to monitor cells in humans using MRI (magnetic resonance imaging).

Dr Mark Lythgoe, UCL Centre for Advanced Biomedical Imaging, the senior author on the study, said: "Because the material we used in this method is already FDA approved we could see this technology being applied in human clinical trials within 3-5 years. It's feasible that heart attacks and other vascular injuries could eventually be treated using regular injections of magnetised stem cells. The technology could be adapted to localise cells in other organs and provide a useful tool for the systemic injection of all manner of cell therapies. And it's not just limited to cells – by focusing tagged antibodies or viruses using this method, cancerous tumours could be much more specifically targeted"

Panagiotis Kyrtatos, also from the UCL Centre for Advanced Biomedical Imaging and lead researcher of the study, added: "This research tackles one of the most critical challenges in the biomedical sciences today: ensuring the effective delivery and retention of cellular therapies to specific targets within the body.

"Cell therapies could greatly benefit from nano-magnetic techniques which concentrate cells where they are needed most. The nano-magnets not only assist with the targeting, but with the aid of MRI also allow us to observe how the cells behave once they're injected."

This work was supported by public and charitable funding from the UCL Institute of Child Health (Child Health Research Appeal Trust), The British Heart Foundation, the Alexander S. Onassis Public Benefit Foundation and the Biotechnology and Biological Sciences Research Council (BBSRC).

Journal reference:

Panagiotis G. Kyrtatos, Pauliina Lehtolainen, Manfred Junemann-Ramirez, Ana Garcia-Prieto, Anthony N. Price, John F. Martin, David G. Gadian, Quentin A. Pankhurst, Mark F. Lythgoe. Magnetic Tagging Increases Delivery of Circulating Progenitors in Vascular Injury. JACC Cardiovascular Interventions, 2009; 2 (8): 794 DOI: 10.1016/j.jcin.2009.05.014

Adapted from materials provided by University College London.

Source

History:	Presented 12 November 2008; received 13 October 2008; accepted 23 October 2008; published 5 March 2009
Permalink:	http://link.aip.org/link/?JAPIAU/105/07B306/1

United States Patent	7,390,962
Greiff , et al.	June 24, 2008

Inventors:	Greiff; Paul (Wayland, MA), DiMatteo; Robert Stephen (Belmont, MA)
Assignee:	The Charles Stark Draper Laboratory, Inc. (Cambridge, MA)
Appl. No.:	10/443,414
Filed:	May 22, 2003

Pub. No.:		WO/2009/129321		International Application No.:		PCT/US2009/040688
Publication Date:		22.10.2009		International Filing Date:		15.04.2009