Tag Archives: University of Buffalo

A nanoparticle for a medical imaging machine that doesn’t exist yet

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Researchers at the University of Buffalo (New York state) have created a nanoparticle that can be detected by six imaging devices according to a Jan. 20, 2015 news item on ScienceDaily,

It’s technology so advanced that the machine capable of using it doesn’t yet exist.

Using two biocompatible parts, University at Buffalo researchers and their colleagues have designed a nanoparticle that can be detected by six medical imaging techniques:

• computed tomography (CT) scanning;

• positron emission tomography (PET) scanning;

• photoacoustic imaging;

• fluorescence imaging;

• upconversion imaging; and

• Cerenkov luminescence imaging.

The advantages are obvious should somebody, somewhere create a hexamodal (aka, multimodal, aka hypmodal) sensing device capable of exploiting the advantages of this nanoparticle as the researchers hope.

A Jan. 20, 2015 University of Buffalo news release (also on EurekAlert) by Charlotte Hsu, which originated the news item, describes the ideas underlying the research,

This kind of “hypermodal” imaging — if it came to fruition — would give doctors a much clearer picture of patients’ organs and tissues than a single method alone could provide. It could help medical professionals diagnose disease and identify the boundaries of tumors.

“This nanoparticle may open the door for new ‘hypermodal’ imaging systems that allow a lot of new information to be obtained using just one contrast agent,” says researcher Jonathan Lovell, PhD, UB assistant professor of biomedical engineering. “Once such systems are developed, a patient could theoretically go in for one scan with one machine instead of multiple scans with multiple machines.”

When Lovell and colleagues used the nanoparticles to examine the lymph nodes of mice, they found that CT and PET scans provided the deepest tissue penetration, while the photoacoustic imaging showed blood vessel details that the first two techniques missed.

Differences like these mean doctors can get a much clearer picture of what’s happening inside the body by merging the results of multiple modalities.

A machine capable of performing all six imaging techniques at once has not yet been invented, to Lovell’s knowledge, but he and his coauthors hope that discoveries like theirs will spur development of such technology.

The news release also offers a description of the nanoparticles,

The researchers designed the nanoparticles from two components: An “upconversion” core that glows blue when struck by near-infrared light, and an outer fabric of porphyrin-phospholipids (PoP) that wraps around the core.

Each part has unique characteristics that make it ideal for certain types of imaging.

The core, initially designed for upconversion imaging, is made from sodium, ytterbium, fluorine, yttrium and thulium. The ytterbium is dense in electrons — a property that facilitates detection by CT scans.

The PoP wrapper has biophotonic qualities that make it a great match for fluorescence and photoacoustic imagining. The PoP layer also is adept at attracting copper, which is used in PET and Cerenkov luminescence imaging.

“Combining these two biocompatible components into a single nanoparticle could give tomorrow’s doctors a powerful, new tool for medical imaging,” says Prasad, also a SUNY Distinguished Professor of chemistry, physics, medicine and electrical engineering at UB. “More studies would have to be done to determine whether the nanoparticle is safe to use for such purposes, but it does not contain toxic metals such as cadmium that are known to pose potential risks and found in some other nanoparticles.”

“Another advantage of this core/shell imaging contrast agent is that it could enable biomedical imaging at multiple scales, from single-molecule to cell imaging, as well as from vascular and organ imaging to whole-body bioimaging,” Chen adds. “These broad, potential capabilities are due to a plurality of optical, photoacoustic and radionuclide imaging abilities that the agent possesses.”

Lovell says the next step in the research is to explore additional uses for the technology.

For example, it might be possible to attach a targeting molecule to the PoP surface that would enable cancer cells to take up the particles, something that photoacoustic and fluorescence imaging can detect due to the properties of the smart PoP coating. This would enable doctors to better see where tumors begin and end, Lovell says.

The researchers have provided two images,

This transmission electron microscopy image shows the nanoparticles, which consist of a core that glows blue when struck by near-infrared light, and an outer fabric of porphyrin-phospholipids (PoP) that wraps around the core. Credit: Jonathan Lovell

This transmission electron microscopy image shows the nanoparticles, which consist of a core that glows blue when struck by near-infrared light, and an outer fabric of porphyrin-phospholipids (PoP) that wraps around the core.
Credit: Jonathan Lovell

University at Buffalo researchers and colleagues have designed a nanoparticle detectable by six medical imaging techniques. This illustration depicts the particles as they are struck by beams of energy and emit signals that can be detected by the six methods: CT and PET scanning, along with photoacoustic, fluorescence, upconversion and Cerenkov luminescence imaging. Credit: Jonathan Lovell

University at Buffalo researchers and colleagues have designed a nanoparticle detectable by six medical imaging techniques. This illustration depicts the particles as they are struck by beams of energy and emit signals that can be detected by the six methods: CT and PET scanning, along with photoacoustic, fluorescence, upconversion and Cerenkov luminescence imaging.
Credit: Jonathan Lovell

Here’s a link to and a citation for the paper,

Hexamodal Imaging with Porphyrin-Phospholipid-Coated Upconversion Nanoparticles by James Rieffel, Feng Chen, Jeesu Kim, Guanying Chen, Wei Shao, Shuai Shao, Upendra Chitgupi, Reinier Hernandez, Stephen A. Graves, Robert J. Nickles, Paras N. Prasad, Chulhong Kim, Weibo Cai, and Jonathan F. Lovell. Advanced Materials DOI: 10.1002/adma.201404739 Article first published online: 14 JAN 2015

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This article is behind a paywall.

Nanorobotic approach to studying how skin falls apart

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Scientists have combined robotic techniques with atomic force microscopy to achieve understanding of how skin falls apart at the nanoscale. From a Sept. 11, 2014 news item on Azonano,

University at Buffalo researchers and colleagues studying a rare, blistering disease have discovered new details of how autoantibodies destroy healthy cells in skin. This information provides new insights into autoimmune mechanisms in general and could help develop and screen treatments for patients suffering from all autoimmune diseases, estimated to affect 5-10 percent of the U.S. population.

…

“Our work represents a unique intersection between the fields of biology and engineering that allowed for entirely new investigational strategies applied to the study of clinical disease,” says Animesh A. Sinha, MD, PhD, Rita M. and Ralph T. Behling Professor and chair of the Department of Dermatology in the UB School of Medicine and Biomedical Sciences and senior author on the study.

A Sept. 9, 2014 University of Buffalo news release by Ellen Goldbaum (also on EurekAlert dated Sept. 10, 2014), which originated the news item, describes the condition and the research in more detail,

PV [Pemphigus Vulgaris] results in the often painful blistering of the skin and mucous membranes. Generally treated with corticosteroids and other immunosuppressive agents, the condition is life-threatening if untreated.

…

Sinha’s research team, in collaboration with scientists at Michigan State University, describe the use of atomic force microscopy (AFM), a technique originally developed to study nonbiological materials, to look at cell junctions and how they rupture, a process called acantholysis.

“It has been very difficult to study cell junctions, which maintain the skin’s barrier function by keeping cells attached to each other,” says Sinha. “These junctions, micron-sized spots on cell membranes, are very complex molecular structures. Their small size has made them resistant to detailed investigation.”

Sinha’s interest lies in determining what destroys those junctions in Pemphigus Vulgaris.

“We haven’t understood why some antibodies generated by the condition cause blisters and why other antibodies it generates do not,” says Sinha.

By studying the connections between skin cells using AFM and other techniques that probe cells at the nanoscale, Sinha and his colleagues report that pathogenic antibodies change structural and functional properties of skin cells in distinct ways.

“Our data suggest a new model for the action of autoantibodies in which there are two steps or ‘hits’ in the development of lesions,” says Sinha. “The first hit results in the initial separation of cells but only the pathogenic antibodies drive further intracellular changes that lead to the breaking of the cell junction and blistering.”

The researchers examined the cells using AFM, which requires minimal sample preparation and provides three-dimensional images of cell surfaces.

The AFM tip acts like a little probe, explains Sinha. When tapped against a cell, it sends back information regarding the cell’s mechanical properties, such as thickness, elasticity, viscosity and electrical potential.

“We combined existing and novel nanorobotic techniques with AFM, including a kind of nanodissection, where we physically detached cells from each other at certain points so that we could test what that did to their mechanical and biological functions,” Sinha adds.

Those data were then combined with information about functional changes in cell behavior to develop a nanomechanical profile, or phenotype, for specific cellular states.

He also envisions that this kind of nanomechanical phenotyping should allow for the development of predictive models for cellular behavior for any kind of cell.

“Ultimately, in the case of autoimmunity, we should be able to use these techniques as a high-throughput assay to screen hundreds or thousands of compounds that might block the effects of autoantibodies and identify novel agents with therapeutic potential in given individuals,” says Sinha.  “Such strategies aim to advance us toward a new era of personalized medicine”.

I found some more information about the nanorobotics technique, mentioned in the news release, in the researchers’ paper (Note: A link has been removed),

Nanorobotic surgery

AFM-based nanorobotics enables accurate and convenient sample manipulation and drug delivery. This capability was used in the current study to control the AFM tip position over the intercellular junction area, and apply vertical indentation forces, so that bundles of intercellular adhesion structures can be dissected precisely with an accuracy of less than 100 nm in height. We used a tip sharp enough (2 nm in tip apex diameter) to penetrate the cell membrane and the intermediate filaments. It has been shown that intermediate filaments have extremely high tensile strength by in vitro AFM stretching [19]. Thus, the vertical force and moving speed of the AFM cantilever (0.06 N/m in vertical spring constant) was controlled at a vertical force of 5 nN at an indentation speed of 0.1 µm/s to guarantee the rupture of the filament and to partially dissect cell adhesion structures between two neighboring cells.

For those who want to know more, here’s a link to and a citation for the paper,

Nanorobotic Investigation Identifies Novel Visual, Structural and Functional Correlates of Autoimmune Pathology in a Blistering Skin Disease Model by Kristina Seiffert-Sinha, Ruiguo Yang, Carmen K. Fung, King W. Lai, Kevin C. Patterson, Aimee S. Payne, Ning Xi, Animesh A. Sinha. PLOSONE Published: September 08, 2014 DOI: 10.1371/journal.pone.0106895

This is an open access paper.

Cooling it—an application using carbon nanotubes and a theory that hotter leads to cooler

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The only thing these two news items have in common is their focus on cooling down electronic devices. Well, there’s also the fact that the work is being done at the nanoscale.

First, there’s a Jan. 23, 2014 news item on Azonano about a technique using carbon nanotubes to cool down microprocessors,

“Cool it!” That’s a prime directive for microprocessor chips and a promising new solution to meeting this imperative is in the offing. Researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have developed a “process friendly” technique that would enable the cooling of microprocessor chips through carbon nanotubes.

Frank Ogletree, a physicist with Berkeley Lab’s Materials Sciences Division, led a study in which organic molecules were used to form strong covalent bonds between carbon nanotubes and metal surfaces. This improved by six-fold the flow of heat from the metal to the carbon nanotubes, paving the way for faster, more efficient cooling of computer chips. The technique is done through gas vapor or liquid chemistry at low temperatures, making it suitable for the manufacturing of computer chips.

The Jan. 22, 2014 Berkeley Lab news release (also on EurekAlert), which originated the news item, describes the nature  of the problem in more detail,

Overheating is the bane of microprocessors. As transistors heat up, their performance can deteriorate to the point where they no longer function as transistors. With microprocessor chips becoming more densely packed and processing speeds continuing to increase, the overheating problem looms ever larger. The first challenge is to conduct heat out of the chip and onto the circuit board where fans and other techniques can be used for cooling. Carbon nanotubes have demonstrated exceptionally high thermal conductivity but their use for cooling microprocessor chips and other devices has been hampered by high thermal interface resistances in nanostructured systems.

“The thermal conductivity of carbon nanotubes exceeds that of diamond or any other natural material but because carbon nanotubes are so chemically stable, their chemical interactions with most other materials are relatively weak, which makes for  high thermal interface resistance,” Ogletree says. “Intel came to the Molecular Foundry wanting to improve the performance of carbon nanotubes in devices. Working with Nachiket Raravikar and Ravi Prasher, who were both Intel engineers when the project was initiated, we were able to increase and strengthen the contact between carbon nanotubes and the surfaces of other materials. This reduces thermal resistance and substantially improves heat transport efficiency.”

The news release then describes the proposed solution,

Sumanjeet Kaur, lead author of the Nature Communications paper and an expert on carbon nanotubes, with assistance from co-author and Molecular Foundry chemist Brett Helms, used reactive molecules to bridge the carbon nanotube/metal interface – aminopropyl-trialkoxy-silane (APS) for oxide-forming metals, and cysteamine for noble metals. First vertically aligned carbon nanotube arrays were grown on silicon wafers, and thin films of aluminum or gold were evaporated on glass microscope cover slips. The metal films were then “functionalized” and allowed to bond with the carbon nanotube arrays. Enhanced heat flow was confirmed using a characterization technique developed by Ogletree that allows for interface-specific measurements of heat transport.

“You can think of interface resistance in steady-state heat flow as being an extra amount of distance the heat has to flow through the material,” Kaur says. “With carbon nanotubes, thermal interface resistance adds something like 40 microns of distance on each side of the actual carbon nanotube layer. With our technique, we’re able to decrease the interface resistance so that the extra distance is around seven microns at each interface.”

Although the approach used by Ogletree, Kaur and their colleagues substantially strengthened the contact between a metal and individual carbon nanotubes within an array, a majority of the nanotubes within the array may still fail to connect with the metal. The Berkeley team is now developing a way to improve the density of carbon nanotube/metal contacts. Their technique should also be applicable to single and multi-layer graphene devices, which face the same cooling issues.

For anyone who’s never heard of the Molecular Foundry before (from the news release),

The Molecular Foundry is one of five DOE [Department of Energy] Nanoscale Science Research Centers (NSRCs), national user facilities for interdisciplinary research at the nanoscale, supported by the DOE Office of Science. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize, and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE’s Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos national laboratories.

My second item comes from the University of Buffalo (UB), located in the US. From a Jan. 21, 2014 University of Buffalo news release by Cory Nealon (also on EurekAlert),

Heat in electronic devices is generated by the movement of electrons through transistors, resistors and other elements of an electrical network. Depending on the network, there are a variety of ways, such as cooling fans and heat sinks, to prevent the circuits from overheating.

But as more integrated circuits and transistors are added to devices to boost their computing power, it’s becoming more difficult to keep those elements cool. Most nanoelectrics research centers are working to develop advanced materials that are capable of withstanding the extreme environment inside smartphones, laptops and other devices.

While advanced materials show tremendous potential, the UB research suggests there may still be room within the existing paradigm of electronic devices to continue developing more powerful computers.

To support their findings, the researchers fabricated nanoscale semiconductor devices in a state-of-the-art gallium arsenide crystal provided to UB by Sandia’s Reno [John L. Reno, Center for Integrated Nanotechnologies at Sandia National Laboratories]. The researchers then subjected the chip to a large voltage, squeezing an electrical current through the nanoconductors. This, in turn, increased the amount of heat circulating through the chip’s nanotransistor.

But instead of degrading the device, the nanotransistor spontaneously transformed itself into a quantum state that was protected from the effect of heating and provided a robust channel of electric current. To help explain, Bird [Jonathan Bird, UB professor of electrical engineering] offered an analogy to Niagara Falls.

“The water, or energy, comes from a source; in this case, the Great Lakes. It’s channeled into a narrow point (the Niagara River) and ultimately flows over Niagara Falls. At the bottom of waterfall is dissipated energy. But unlike the waterfall, this dissipated energy recirculates throughout the chip and changes how heat affects, or in this case doesn’t affect, the network’s operation.”

While this behavior may seem unusual, especially conceptualizing it in terms of water flowing over a waterfall, it is the direct result of the quantum mechanical nature of electronics when viewed on the nanoscale. The current is made up of electrons which spontaneously organize to form a narrow conducting filament through the nanoconductor. It is this filament that is so robust against the effects of heating.

“We’re not actually eliminating the heat, but we’ve managed to stop it from affecting the electrical network. In a way, this is an optimization of the current paradigm,” said Han [J. E. Han, UB Dept. of Physics], who developed the theoretical models which explain the findings.

What an interesting and counter-intuitive approach to managing the heat in our devices.

For those who want more, here’s a link to and citation for the carbon nanotube paper,

Enhanced thermal transport at covalently functionalized carbon nanotube array interfaces by Sumanjeet Kaur, Nachiket Raravikar, Brett A. Helms, Ravi Prasher, & D. Frank Ogletree. Nature Communications 5, Article number: 3082 doi:10.1038/ncomms4082 Published 22 January 2014

This paper is behind a paywall.

Now here’s a link to and a citation for the ‘making it hotter to make it cooler’ paper,

Formation of a protected sub-band for conduction in quantum point contacts under extreme biasing by J. Lee, J. E. Han, S. Xiao, J. Song, J. L. Reno, & J. P. Bird. Nature Nanotechnology (2014) doi:10.1038/nnano.2013.297 Published online 19 January 2014

This paper is behind a paywall although there is an option to preview it for free via ReadCube Access.

Paranoids celebrate! New wireless technology in the body coming soon

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I have a paranoid neighbour who I’m hoping will never hear about this research—thankfully, she doesn’t read blogs—because the idea someone could be monitoring her bodily functions wirelessly would fit in beautifully and likely exacerbate her delusions.

According to the May 31, 2013 news item on ScienceDaily, the idea of creating a ‘body area’ network is not new, the technology the researchers at the University of Buffalo are developing features a new approach to this research,

The military has for decades used sonar for underwater communication.

Now, researchers at the University at Buffalo are developing a miniaturized version of the same technology to be applied inside the human body to treat diseases such as diabetes and heart failure in real time.

The advancement relies on sensors that use ultrasounds — the same inaudible sound waves used by the navy for sonar and doctors for sonograms — to wirelessly share information between medical devices implanted in or worn by people.

“This is a biomedical advancement that could revolutionize the way we care for people suffering from the major diseases of our time,” said Tommaso Melodia, PhD, UB associate professor of electrical engineering.

The University of Buffalo May 31, 2013 news release by Cory Nealon details the project and the approach to developing a ‘proof of concept’ for this theory about ultrasound and wireless communication within the body,

His [Melodia] research, “Towards Ultrasonic Networking for Implantable Biomedical Device,” is supported by a five-year, $449,000 National Science Foundation (NSF) CAREER grant. The CAREER award is the foundation’s most prestigious for young investigators.

Details of Melodia’s work can be found at: http://1.usa.gov/17y2njQ.

…

… most work has focused on linking sensors together via electromagnetic radio frequency waves – the same type used in cellular phones, GPS units and other common wireless devices.

Radio waves can be effective but they have drawbacks such as the heat they generate. Also, because radio waves propagate poorly through skin, muscle and other body tissue, they require relatively large amounts of energy, he said.

Ultrasounds may be a more efficient way to share information, Melodia said, because roughly 65 percent of the body is composed of water. This suggests that medical devices, such as a pacemaker and an instrument that measures blood oxygen levels, could communicate more effectively via ultrasounds compared to radio waves.

“Think of how the Navy uses sonar to communicate between submarines and detect enemy ships,” Melodia said. “It’s the same principle, only applied to ultrasonic sensors that are small enough to work together inside the human body and more effectively help treat diseases.”

Another example involves connecting blood glucose sensors with implantable insulin pumps. The sensors would monitor the blood and regulate, through the pumps, the dosage of insulin as needed in real time.

“We are really just scratching the surface of what’s possible. There are countless potential applications,” he said.

Melodia will use the NSF grant to do more modeling and conduct experiments with ultrasonic, wireless body sensor networks. The grant will support UB PhD student G. Enrico Santagati, who already has contributed significantly to the project, as well as UB undergraduate students.

The research will address issues such as how to:

  • design transmission schemes to accurately relay information between sensors without causing body tissue to overheat
  • design networking protocols specialized for intra-body sensors
  • how to model ultrasonic interference
  • accurately simulate ultrasonic networks
  • design the first existing reconfigurable testbed for experimental evaluation of ultrasonic networks.

Melodia is a member of the Signals, Communications and Networking Research Group in UB’s Department of Electrical Engineering in the School of Engineering and Applied Sciences. The group carries out research in: wireless communications and networking, cognitive radios, extreme environment (i.e., underwater, underground) communications, secure communications, data hiding, information theory and coding, adaptive signal processing, compressed sensing,  multimedia systems, magnetic resonance imaging and radar systems.

Other members of the group include professors Stella N. Batalama, Adly T. Fam, Dimitris A. Pados, Mehrdad Soumekh; associate professors Michael Langberg, Weifeng Su and Leslie Ying; and assistant professors Nicholas Mastronarde, Gesualdo Scutari, Zhi Sun, Josep M. Jornet.

I wonder if this technology, once the bugs have been ironed out, will be appealing to hypochondriacs.

Zimbabwe’s plans for nanotechnology-enabled drug treatments for tuberculosis and HIV/AIDS

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It’s a big gamble for a country that has a relatively small national budget but Zimbabwe is focusing a significant chunk of its science funding to nanotechnology-enabled drug treatments according to the Dec. 11, 2012 news article by Munyaradzi Makoni for scidev.net,

The Zimbabwean government has shown signs of embracing nanotechnology, earmarking it for extensive funding from the science ministry’s 2013 budget for new programmes.

According to Rungano Karimanzira, director of commercialisation of research and development at the ministry, 60 per cent of the new programme funding has been allocated to nanotechnology — a move announced with the unveiling of the national budget last month (16 November).

After years of political instability and international isolation, Zimbabwe now aims to revive science and use nanotechnology to research and produce drugs, particularly treatments for tuberculosis (TB) and HIV/AIDS.

Clive Mphambela’s Nov. 16, 2012 article for the Zimbabwe Independent (accessed Dec. 13, 2012 from The Zimbabwe Situation) describes the country’s 2013 budget and Zimbabwe’s economic situation,

FINANCE Minister Tendai Biti yesterday presented a paltry US$3,8 billion
“developmental budget”, describing it as the most difficult to construct in
the short life of the inclusive government.

…

Biti’s budget is smaller than South Africa’s retail chain supermarket group,
Pick n Pay whose average annual turnover is R55,3 billion (US$6,1 billion).

However, he said numerous downside risks, including potential political
instability, threatened his budget.

Biti said the multitude of challenges facing the economy required a
fundamental re-think of the state, economics and development in Zimbabwe.

“In this regard, the 2013 national budget seeks to offer leadership and
direction on the bold structural measures that must be taken to unleash
Zimbabwe’s growth potential in pursuit of the MTP’s [Medium Term Plan] vision of constructing a
modern democratic developmental state,” said Biti.

The Finance minister proposed a 15-point roadmap which would in the
short-term seek to reverse the current slow-down and refocus the economy on
a higher growth trajectory.

Even before the 2013 budget was announced, Zimbabwe’s national nanotechnology programme was making news (from the Makoni article),

The country’s first national nanotechnology programme was launched in October by science and technology development minister Heneri Dzinotyiwei during the opening of the Zimbabwe Nanotechnology Centre (ZINC) at the University of Zimbabwe in Harare.

Dzinotyiwei said the programme will focus on developing medicinal drugs, and will identify and undertake studies in nanomedicine geared towards bringing benefits to the entire country.

“We hope that we can ultimately dedicate around US$1 million to the nanotechnology programme,” he said.

ZINC and its nanomedicine-focused partnership with the University of Zimbabwe, the University of Buffalo and Chinhoyi University of Technology was mentioned here in a Sept. 24, 2012 posting.

More on quantum dots: a toxicity study; Merck action in Israel

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I have two items on quantum dots today. The first concerns a toxicity study performed on primates at the University of Buffalo (NY, USA). From the May 22, 2012 news item by Will Soutter for Azonano,

A multi-institute toxicity study on quantum dots in primates has discovered that these nanocrystals are safe for a period of one year.

This finding is encouraging for researchers and physicians looking for novel techniques to treat diseases such as cancer using nanomedicine. The organizations involved in the study included the University at Buffalo, Nanyang Technological University, ChangChun University of Science and Technology, and the Chinese PLA General Hospital.

On digging a little further, I found this information on the University of Buffalo website, from their May 21, 2012 news release,

— Tiny luminescent crystals called quantum dots hold great promise as tools for treating and detecting diseases like cancer.

— A pioneering study to gauge the toxicity of quantum dots in primates has found cadmium-selenide quantum dots to be safe over intervals of time ranging from three months to a year. The study is likely the first to test the safety of quantum dots in primates.

— The authors say more research is needed to determine quantum dots’ long-term effect on health; elevated levels of cadmium from the quantum dots were found in the primates even after 90 days.

The research, which appeared on May 20 in Nature Nanotechnology online , is likely the first to test the safety of quantum dots in primates.

In the study, scientists found that four rhesus monkeys injected with cadmium-selenide quantum dots remained in normal health over 90 days. Blood and biochemical markers stayed in typical ranges, and major organs developed no abnormalities. The animals didn’t lose weight.

Two monkeys observed for an additional year also showed no signs of illness.

The first  results are hopeful but there are some concerns,

The new toxicity study — completed by the University at Buffalo, the Chinese PLA General Hospital, China’s ChangChun University of Science and Technology, and Singapore’s Nanyang Technological University — begins to address the concern of health professionals who worry that quantum dots may be dangerous to humans.

The authors caution, however, that more research is needed to determine the nanocrystals’ long-term effects in primates; most of the potentially toxic cadmium from the quantum dots stayed in the liver, spleen and kidneys of the animals studied over the 90-day period.

…

The cadmium build-up, in particular, is a serious concern that warrants further investigation, said Ken-Tye Yong, a Nanyang Technological University assistant professor who began working with Prasad [Paras N. Prasad] on the study as a postdoctoral researcher at UB.

Unusually, this article seems to be open access at Nature Nanotechnology,

A pilot study in non-human primates shows no adverse response to intravenous injection of quantum dots

Ling Ye, Ken-Tye Yong, Liwei Liu, Indrajit Roy, Rui Hu, Jing Zhu, Hongxing Cai, Wing-Cheung Law, Jianwei Liu, Kai Wang, Jing Liu, Yaqian Liu, Yazhuo Hu, Xihe Zhang, Mark T. Swihart, and Paras N. Prasad

Nature Nanotechnology (2012) doi:10.1038/nnano.2012.74

The acquisition of an Israeli quantum dot company by Merck is my second bit of quantum dot news, from the May 22, 2012 news item on Nanowerk,

Merck announced today that within the scope of a capital increase by the Israeli start-up company QLight Nanotech, it is acquiring an interest in the Jerusalem-based company. QLight Nanotech is a spin-off subsidiary of Yissum, the technology transfer company of the Hebrew University of Jerusalem. QLight Nanotech develops products for use in displays and energy-efficient light sources based on semiconductor nanoparticles known as quantum dots.

I understood that Merck was a pharmaceutical company so I was bit surprised to see this (from the May 22, 2012 news item on the Solid State Technology website)

“I am excited that our basic science discoveries on semiconductor nanocrystals are now being realized in innovative technological applications. The partnership with Merck, a world leader in materials for display applications, is a synergistic one allowing us at Qlight Nanotech to implement advanced chemicals manufacturing and applications’ know-how,” said the scientific founder of  QLight Nanotech, Professor Uri Banin of the Hebrew University of Jerusalem, who will continue to support the company as a shareholder and advisor alongside of Yissum.

In fact, Merck bills itself as a pharmaceuticals and a s chemicals company.

Rainbows, what are we going to do with them?

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The title is attention-getting initially then quickly leads to confusion for anyone not familiar with plasmonics, “Trapping a rainbow: Researchers slow broadband light waves with plasmonic structures.” I have to confess to being more interested in the use of the metaphor than I am in the science. However in deference to any readers who are more taken by the science, here’s more from the March 14, 2011 news item on Nanowerk,

A team of electrical engineers and chemists at Lehigh University have experimentally verified the “rainbow” trapping effect, demonstrating that plasmonic structures can slow down light waves over a broad range of wavelengths.

The idea that a rainbow of broadband light could be slowed down or stopped using plasmonic structures has only recently been predicted in theoretical studies of metamaterials. The Lehigh experiment employed focused ion beams to mill a series of increasingly deeper, nanosized grooves into a thin sheet of silver. By focusing light along this plasmonic structure, this series of grooves or nano-gratings slowed each wavelength of optical light, essentially capturing each individual color of the visible spectrum at different points along the grating. The findings hold promise for improved data storage, optical data processing, solar cells, bio sensors and other technologies.

While the notion of slowing light or trapping a rainbow sounds like ad speak, finding practical ways to control photons—the particles that makes up light— could significantly improve the capacity of data storage systems and speed the processing of optical data.

The research required the ability to engineer a metallic surface to produce nanoscale periodic gratings with varying groove depths. This alters the optical properties of the nanopatterned metallic surface, called Surface Dispersion Engineering. The broadband surface light waves are then trapped along this plasmonic metallic surface with each wavelength trapped at a different groove depth, resulting in a trapped rainbow of light.

You can get still more scientific detail in the item but I found a later posting, April 12, 2011 news item, also on Nanowerk, where the researcher Qiaoquiang Gan (pronounced “Chow-Chung” and “Gone”) gave this description for his work,

An electrical engineer at the University at Buffalo, who previously demonstrated experimentally the “rainbow trapping effect” [emphasis mine] — a phenomenon that could boost optical data storage and communications — is now working to capture all the colors of the rainbow.

In a paper published March 29 in the Proceedings of the National Academy of Sciences, Qiaoquiang Gan (pronounced “Chow-Chung” and “Gone”), PhD, an assistant professor of electrical engineering at the University at Buffalo’s School of Engineering and Applied Sciences, and his colleagues at Lehigh University, where he was a graduate student, described how they slowed broadband light waves using a type of material called nanoplasmonic structures.

Gan explains that the ultimate goal is to achieve a breakthrough in optical communications called multiplexed, multiwavelength communications, where optical data can potentially be tamed at different wavelengths, thus greatly increasing processing and transmission capacity.
…
“Light is usually very fast, but the structures I created can slow broadband light significantly,” says Gan. “It’s as though I can hold [emphasis mine] the light in my hand.”

I like the notion of ‘holding’ a rainbow better than ‘trapping’ one. (ETA April 18, 2011: The original sentence, now placed at the end of this posting, has been replaced with this: There’s a big difference between the two verbs, trapping and holding and each implies a difference relationship to the object. Which would you prefer, to be trapped or to be held? What does it mean to the one who does the trapping or the holding? Two difference relationships to the object and to the role of a scientist are implied.

It’s believed that the metaphors we use when describing science have a powerful impact on how science is viewed and practiced. One example I have at hand is a study by Kevin Dunbar mentioned in my Jan. 4, 2010 posting (scroll down) where he illustrates how scientists use metaphors to achieve scientific breakthroughs. Logically, if metaphors help us achieve breakthroughs, then they are quite capable of constraining us as well.

Meanwhile, this gives me an excuse to include this video of a Hawaiian singer, Israel Kamakawiwo’ole and his extraordinary version of Somewhere over the Rainbow. Happy Weekend!

The original (April 15, 2011) sentence:
It’s more gentle and implies a more humble attitude and I suspect it would ultimately prove more fruitful.

Nigeria and nanotechnology

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The March 6, 2011 news item on Nanowerk specifically concerns the development of nanomedicine facilities and teaching in Nigerian Universities,

The National Universities Commission (NUC) has signed a Memorandum of Understanding (MOU) with the Institute for Lasers, Photonics, and Biophotonics (ILPB), United States of America for the development of an international joint research centre for nanomedicine in some Nigerian universities.

According to details of the MOU, the first phase of the initiative is to implement the program at NUC-selected universities while the second phase will bring Nigerian researchers to train at ILPB and equipment distributed to Nigerian universities. The MOU postulates that by this time, there should be “global impact of research with widespread implementation of quantum dots and other nanoparticles in the fields of medical diagnosis and treatment.” The third stage, meant to take place five to 10 years from now, will be defined by major research focuses, sufficient funding, and effective personnel training and the centre is expected to become a first-class research center not only in Nigeria, but in the world.

The NUC appointed Paras Prasad, a professor of chemistry and medicine with the University of Buffalo (UB) and the executive director of the ILPB, as the head of the joint research center.

“The two major application areas are alternate energy and health care. We are applying this merge of photonics, of light wave energy, for application in the area of medicine called nanomedicine. The other, alternative energy focuses primarily on solar energy harvesting,” he said.

Despite the reference to alternative energy the primary focus, according to Folarin Erogbogbo, leader of the Nigerian group and research assistant professor in cancer nanotechnology, is nanomedicine.