Tag Archives: gold nanoparticles

Cute, adorable roundworms help measure nanoparticle toxicity

Caption: Low-cost experiments to test the toxicity of nanomaterials focused on populations of roundworms. Rice University scientists were able to test 20 nanomaterials in a short time, and see their method as a way to determine which nanomaterials should undergo more extensive testing. Credit: Zhong Lab/Rice University

Caption: Low-cost experiments to test the toxicity of nanomaterials focused on populations of roundworms. Rice University scientists were able to test 20 nanomaterials in a short time, and see their method as a way to determine which nanomaterials should undergo more extensive testing.
Credit: Zhong Lab/Rice University

Until now, ‘cute’ and ‘adorable’ are not words I would have associated with worms of any kind or with Rice University, for that matter. It’s amazing what a single image can do, eh?

A Feb. 3, 2015 news item on Azonano describes how roundworms have been used in research investigating the toxicity of various kinds of nanoparticles,

The lowly roundworm is the star of an ambitious Rice University project to measure the toxicity of nanoparticles.

The low-cost, high-throughput study by Rice scientists Weiwei Zhong and Qilin Li measures the effects of many types of nanoparticles not only on individual organisms but also on entire populations.

A Feb. 2, 2015 Rice University news release (also on EurekAlert), which originated the news item, provides more details about the research,

The Rice researchers tested 20 types of nanoparticles and determined that five, including the carbon-60 molecules (“buckyballs”) discovered at Rice in 1985, showed little to no toxicity.

Others were moderately or highly toxic to Caenorhabditis elegans, several generations of which the researchers observed to see the particles’ effects on their health.

The results were published by the American Chemical Society journal Environmental Sciences and Technology. They are also available on the researchers’ open-source website.

“Nanoparticles are basically new materials, and we don’t know much about what they will do to human health and the health of the ecosystem,” said Li, an associate professor of civil and environmental engineering and of materials science and nanoengineering. “There have been a lot of publications showing certain nanomaterials are more toxic than others. So before we make more products that incorporate these nanomaterials, it’s important that we understand we’re not putting anything toxic into the environment or into consumer products.

“The question is, How much cost can we bear?” she said. “It’s a long and expensive process to do a thorough toxicological study of any chemical, not just nanomaterials.” She said that due to the large variety of nanomaterials being produced at high speed and at such a large scale, there is “an urgent need for high-throughput screening techniques to prioritize which to study more extensively.”

Rice’s pilot study proves it is possible to gather a lot of toxicity data at low cost, said Zhong, an assistant professor of biosciences, who has performed extensive studies on C. elegans, particularly on their gene networks. Materials alone for each assay, including the worms and the bacteria they consumed and the culture media, cost about 50 cents, she said.

The researchers used four assays to see how worms react to nanoparticles: fitness, movement, growth and lifespan. The most sensitive assay of toxicity was fitness. In this test, the researchers mixed the nanoparticles in solutions with the bacteria that worms consume. Measuring how much bacteria they ate over time served as a measure of the worms’ “fitness.”

“If the worms’ health is affected by the nanoparticles, they reproduce less and eat less,” Zhong said. “In the fitness assay, we monitor the worms for a week. That is long enough for us to monitor toxicity effects accumulated through three generations of worms.” C. elegans has a life cycle of about three days, and since each can produce many offspring, a population that started at 50 would number more than 10,000 after a week. Such a large number of tested animals also enabled the fitness assay to be highly sensitive.

The researchers’ “QuantWorm” system allowed fast monitoring of worm fitness, movement, growth and lifespan. In fact, monitoring the worms was probably the least time-intensive part of the project. Each nanomaterial required specific preparation to make sure it was soluble and could be delivered to the worms along with the bacteria. The chemical properties of each nanomaterial also needed to be characterized in detail.

The researchers studied a representative sampling of three classes of nanoparticles: metal, metal oxides and carbon-based. “We did not do polymeric nanoparticles because the type of polymers you can possibly have is endless,” Li explained.

They examined the toxicity of each nanoparticle at four concentrations. Their results showed C-60 fullerenes, fullerol (a fullerene derivative), titanium dioxide, titanium dioxide-decorated nanotubes and cerium dioxide were the least damaging to worm populations.

Their “fitness” assay confirmed dose-dependent toxicity for carbon black, single- and multiwalled carbon nanotubes, graphene, graphene oxide, gold nanoparticles and fumed silicon dioxide.

They also determined the degree to which surface chemistry affected the toxicity of some particles. While amine-functionalized multiwalled nanotubes proved highly toxic, hydroxylated nanotubes had the least toxicity, with significant differences in fitness, body length and lifespan.

A complete and interactive toxicity chart for all of the tested materials is available online.

Zhong said the method could prove its worth as a rapid way for drug or other companies to narrow the range of nanoparticles they wish to put through more expensive, dedicated toxicology testing.

“Next, we hope to add environmental variables to the assays, for example, to mimic ultraviolet exposure or river water conditions in the solution to see how they affect toxicity,” she said. “We also want to study the biological mechanism by which some particles are toxic to worms.”

Here’s a citation for the paper and links to the paper and to the researchers’ website,

A multi-endpoint, high-throughput study of nanomaterial toxicity in Caenorhabditis elegans by Sang-Kyu Jung, Xiaolei Qu, Boanerges Aleman-Meza, Tianxiao Wang, Celeste Riepe, Zheng Liu, Qilin Li, and Weiwei Zhong. Environ. Sci. Technol., Just Accepted Manuscript DOI: 10.1021/es5056462 Publication Date (Web): January 22, 2015
Copyright © 2015 American Chemical Society

Nanomaterial effects on C. elegans

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This heat map indicates whether a measurement for the nanomaterial-exposed worms is higher (yellow), or lower (blue) than the control worms. Black indicates no effects from nanomaterial exposure.

Clicking on colored blocks to see detailed experimental data.

The published paper is open access but you need an American Chemical Society site registration to access it. The researchers’ site is open access.

Microplasm-generated gold nanoparticles and the heart

Scientists are hoping they’ve found a better way to detect early signs of a heart attack according to a Jan. 15, 2015 news item on Nanotechnology Now,

NYU [New York University] Polytechnic School of Engineering professors have been collaborating with researchers from Peking University on a new test strip that is demonstrating great potential for the early detection of certain heart attacks.

Kurt H. Becker, a professor in the Department of Applied Physics and the Department of Mechanical and Aerospace Engineering, and WeiDong Zhu, a research associate professor in the Department of Mechanical and Aerospace Engineering, are helping develop a new colloidal gold test strip for cardiac troponin I (cTn-I) detection. The new strip uses microplasma-generated gold nanoparticles (AuNPs) and shows much higher detection sensitivity than conventional test strips. The new cTn-I test is based on the specific immune-chemical reactions between antigen and antibody on immunochromatographic test strips using AuNPs.

A Jan. 14, 2015 NYU Polytechnic School of Engineering news release (also on EurekAlert but dated Jan. 15, 2015), which originated the news item, explains what makes these new test strips more sensitive (hint: microplasma-generated gold nanoparticles),

Compared to AuNPs produced by traditional chemical methods, the surfaces of the gold nanoparticles generated by the microplasma-induced liquid chemical process attract more antibodies, which results in significantly higher detection sensitivity.

cTn-I is a specific marker for myocardial infarction. The cTn-I level in patients experiencing cardiac infarction is several thousand times higher than in healthy people. The early detection of cTn-I is therefore a key factor of heart attack diagnosis and therapy.

The use of microplasmas to generate AuNP is yet another application of the microplasma technology developed by Becker and Zhu.  Microplasmas have been used successfully in dental applications (improved bonding, tooth whitening, root canal disinfection), biological decontamination (inactivation of microorganisms and biofilms), and disinfection and preservation of fresh fruits and vegetables.

The microplasma-assisted synthesis of AuNPs has great potential for other biomedical and therapeutic applications such as tumor detection, cancer imaging, drug delivery, and treatment of degenerative diseases such as Alzheimer’s.

The routine use of gold nanoparticles in therapy and disease detection in patients is still years away: longer for therapeutic applications and shorter for biosensors. The biggest hurdle to overcome is the fact that the synthesis of monodisperse, size-controlled gold nanoparticles, even using microplasmas, is still a costly, time-consuming, and labor-intensive process, which limits their use currently to small-scale clinical studies, Becker explained.

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

Microplasma-Assisted Synthesis of Colloidal Gold Nanoparticles and Their Use in the Detection of Cardiac Troponin I (cTn-I) by Ruixue Wang, Shasha Zuo, Dong Wu, Jue Zhang, Weidong Zhu, Kurt H. Becker, and Jing Fang. Plasma Processes and Polymers DOI: 10.1002/ppap.201400127 Article first published online: 11 DEC 2014

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This article is behind a paywall.

For anyone curious about the more common chemical methods of producing gold nanoparticles, there’s this video produced in Australia by TechNyou Education. There’s a specific technique described which I believe is one of the most commonly used and I think this can be generalized to other gold nanoparticle chemical production processes,

One more thing, this video runs over my 5 min. policy limit for videos. To do this, I battled my inclination to include something that I think is useful for understanding more about nanoparticles and my desire to make sure that my blog doesn’t get too bloated.

Of airborne nanomaterials, bacterial microbiomes, viral microbiomes, and paper sensors

There’s a Jan. 14, 2015 news item on Nanowerk from the Virginia Polytechnic Institute (Virginia Tech) which is largely a personal profile featuring some basic information (useful for those new to the topic) about airborne nanoparticles (Note: A link has been removed),

The Harvard educated undergraduate [Linsey Marr,  professor of civil and environmental engineering, Virginia Tech] who obtained her Ph.D. from University of California at Berkeley and trained as a postdoctoral researcher with a Nobel laureate of chemistry at MIT is now among a handful of researchers in the world who are addressing concerns about engineered nanomaterials in the atmosphere.

Marr is part of the National Science Foundation’s Center for the Environmental Implications of Nanotechnology and her research group has characterized airborne nanoparticles at every point of their life cycle. This cycle includes production at a commercial manufacturing facility, use by consumers in the home, and disposal via incineration.

A Jan. 14, 2015 Virginia Tech news release, which originated the news item, quotes Marr on the current thinking about airborne nanoparticles,

“Results have shown that engineered nanomaterials released into the air are often aggregated with other particulate matter, such as combustion soot or ingredients in consumer spray products, and that the size of such aggregates may range from smaller than 10 nanometers to larger than 10 microns,” Marr revealed. She was referring to studies completed by research group members Marina Quadros Vance of Florianopolis, Brazil, a research scientist with the Virginia Tech Institute of Critical Technology and Applied Science, and Eric Vejerano, of Ligao, Philippines, a post-doctoral associate in civil and environmental engineering.

Size matters if these aggregates are inhaled.

Another concern is the reaction of a nanomaterial such as a fullerene with ozone at environmentally relevant concentration levels. Marr’s graduate student, Andrea Tiwari, of Mankato, Minnesota, said the resulting changes in fullerene could lead to enhanced toxicity.

The story then segues into airborne pathogens and viruses eventually honing in on virus microbiomes and bacterial microbiomes (from the news release),

Marr is a former Ironman triathlete who obviously has strong interests in what she is breathing into her own body. So it would be natural for her to expand her study of engineered nanoparticles traveling in the atmosphere to focus on airborne pathogens.

She did so by starting to consider the influenza virus as an airborne pollutant. She applied the same concepts and tools used for studying environmental contaminants and ambient aerosols to the examination of the virus.

She looked at viruses as “essentially self-assembled nanoparticles that are capable of self-replication.”

Her research team became the first to measure influenza virus concentrations in ambient air in a children’s day care center and on airplanes. When they conducted their studies, the Virginia Tech researchers collected samples from a waiting room of a health care center, two toddlers’ rooms and one babies’ area of a childcare center, as well as three cross-country flights between Roanoke, Virginia., and San Francisco. They collected 16 samples between Dec. 10, 2009 and Apr. 22, 2010.

“Half of the samples were confirmed to contain aerosolized influenza A viruses,” Marr said. The childcare samples were the most infected at 75 percent. Next, airplane samples reached 67 percent contamination, and health center numbers came in at 33 percent.

This study serves as a foundation for new work started about a year ago in her lab.

Marr collaborated with Aaron J. Prussin II, of Blacksburg, Virginia, and they successfully secured for him a postdoctoral fellowship from the Alfred P. Sloan Foundation to characterize the bacterial and viral microbiome — the ecological community of microorganisms — of the air in a daycare center.

They are now attempting to determine seasonal changes of both the viral microbiome and the bacterial microbiome in a daycare setting, and examine how changes in the microbiome are related to naturally occurring changes in the indoor environment.

“Little is known about the viral component of the microbiome and it is important because viruses are approximately 10 times more abundant than bacteria, and they help shape the bacterial community. Research suggests that viruses do have both beneficial and harmful interactions with bacteria,” Prussin said.

With Prussin and Marr working together they hope to verify their hypothesis that daycare centers harbor unique, dynamic microbiomes with plentiful bacteria and viruses. They are also looking at what seasonal changes might bring to a daycare setting.

They pointed to the effect of seasonal changes because in previous work, Marr, her former graduate student Wan Yang, of Shantou, China, and Elankumaran Subbiah, a virologist in the biomedical sciences and pathobiology department of the Virginia-Maryland College of Veterinary Medicine, measured the influenza A virus survival rate at various levels of humidity.

Their 2012 study presented for the first time the relationship between the influenza A virus viability in human mucus and humidity over a large range of relative humidities, from 17 percent to 100 percent. They found the viability of the virus was highest when the relative humidity was either close to 100 percent or below 50 percent. The results in human mucus may help explain influenza’s seasonality in different regions.

According to the news release Marr and her colleagues have developed a fast and cheap technology for detection of airborne pathogens (Note: A link has been removed),

With the urgent need to understand the dynamics of airborne pathogens, especially as one considers the threats of bioterrorism, pandemic influenza, and other emerging infectious diseases, Marr said “a breakthrough technology is required to enable rapid, low-cost detection of pathogens in air.”

Along with Subbiah and Peter Vikesland,  professor of civil and environmental engineering, they want to develop readily deployable, inexpensive, paper-based sensors for airborne pathogen detection.

In 2013 they received funding of almost $250,000 from Virginia Tech’s Institute for Critical Technology and Applied Science, a supporter of the clustering of research groups, to support their idea of creating paper-based sensors based on their various successes to date.

Marr explained the sensors “would use a sandwich approach. The bottom layer is paper containing specialized DNA that will immobilize the virus. The middle layer is the virus, which sticks to the specialized DNA on the bottom layer. The top layer is additional specialized DNA that sticks to the virus. This DNA is attached to gold nanoparticles that are easily detectable using a technique known as Raman microscopy.”

They key to their approach is that it combines high-tech with low-tech in the hopes of keeping the assay costs low. Their sampling method will use a bicycle pump, and low cost paper substrates. They hope that they will be able to incorporate smart-phone based signal transduction for the detection. Using this approach, they believe “even remote corners of the world” would be able to use the technique.

Vikesland previously received funding from the Gates Foundation to detect the polio virus via paper-based diagnostics. Polio is still found in countries on the continents of Asia and Africa.

I have previously mentioned Linsey Marr in an Oct. 18, 2013 post about the revival of the Nanotechnology Consumer Products Inventory (originally developed by the Project for Emerging Nanotechnologies) by academics at Virginia Tech and first mentioned CEINT in an Aug. 15, 2011 post about a special project featuring a mesocosm at Duke University (North Carolina).

Detecting Ochratoxin A in agricultural products with gold nanoparticles

Iranian researchers have developed a fast, inexpensive way to test for a cancer-causing toxicant found in some agricultural products. From a Jan. 5, 2015 news item on Nanowerk (Note: A link has been removed),

Researchers from Isfahan University of Technology used gold nanoparticles in the production of a detection kit to find cancerous toxicant in agricultural products (“Ultrasensitive and quantitative gold nanoparticle-based immunochromatographic assay for detection of ochratoxin A in agro-products”).

The use of the kit increases speed, sensitivity and ease of application.

A Jan. 5, 2015 Iran Nanotechnology Initiative Council (INIC) news release, which originated the news item, describes Ochratoxin A and the kit,

Humans and animals are always threatened by various toxicants naturally produced in different food products. Ochratoxin A is a type of toxicant that is produced by some types of fungi, which has been classified in human cancerous materials (Group B2) by the International Agency for Research on Cancer (IARC).

There are many methods to detect this toxicant, but in addition to high costs, these methods are time-consuming and require skillful and expert people to carry out the tests. The fact is that in many places where the detection of ochratoxin A is a necessity, there is no equipment and the detection process fails.

Increasing the detection speed, ease of application, and reducing costs are among the advantages of the method proposed by the researchers. Obtaining technical knowledge for the production of various detection kits based on this method for different materials is another achievement of the researchers.

In this research, a fast and ultra-sensitive detection kit has been produced based on immunochromatography method. To this end, test tapes have been designed and produced by using gold nanoparticles markers, and the results are obtained by placing the sample on the tape after 15 minutes. Gold nanoparticles create red color after combining with the toxicant and the color is visible by naked eye too.

Here’s a link to and a citation for the published research,

Ultrasensitive and quantitative gold nanoparticle-based immunochromatographic assay for detection of ochratoxin A in agro-products by Marjan Majdinasab, Mahmoud Sheikh-Zeinoddin, Sabihe Soleimanian-Zad, Peiwu Li, Qi Zhang, Xin Li, and Xiaoqian Tang. Journal of Chromatography B Volume 974, 1 January 2015, Pages 147–154. doi:10.1016/j.jchromb.2014.10.034

This paper is behind a paywall.

Gold nanoparticles as catalysts for clear water and hydrogen production

The research was published online May 2014 and in a July 2014 print version,  which seems a long time ago now but there’s a renewed interest in attracting attention for this work. A Dec. 17, 2014 news item on phys.org describes this proposed water purification technology from Singapore’s A*STAR (Agency for Science Technology and Research), Note: Links have been removed,

A new catalyst could have dramatic environmental benefits if it can live up to its potential, suggests research from Singapore. A*STAR researchers have produced a catalyst with gold-nanoparticle antennas that can improve water quality in daylight and also generate hydrogen as a green energy source.

This water purification technology was developed by He-Kuan Luo, Andy Hor and colleagues from the A*STAR Institute of Materials Research and Engineering (IMRE). “Any innovative and benign technology that can remove or destroy organic pollutants from water under ambient conditions is highly welcome,” explains Hor, who is executive director of the IMRE and also affiliated with the National University of Singapore.

A Dec. 17, 2014 A*STAR research highlight, which originated the news item, describes the photocatalytic process the research team developed and tested,

Photocatalytic materials harness sunlight to create electrical charges, which provide the energy needed to drive chemical reactions in molecules attached to the catalyst’s surface. In addition to decomposing harmful molecules in water, photocatalysts are used to split water into its components of oxygen and hydrogen; hydrogen can then be employed as a green energy source.

Hor and his team set out to improve an existing catalyst. Oxygen-based compounds such as strontium titanate (SrTiO3) look promising, as they are robust and stable materials and are suitable for use in water. One of the team’s innovations was to enhance its catalytic activity by adding small quantities of the metal lanthanum, which provides additional usable electrical charges.

Catalysts also need to capture a sufficient amount of sunlight to catalyze chemical reactions. So to enable the photocatalyst to harvest more light, the scientists attached gold nanoparticles to the lanthanum-doped SrTiO3 microspheres (see image). These gold nanoparticles are enriched with electrons and hence act as antennas, concentrating light to accelerate the catalytic reaction.

The porous structure of the microspheres results in a large surface area, as it provides more binding space for organic molecules to dock to. A single gram of the material has a surface area of about 100 square meters. “The large surface area plays a critical role in achieving a good photocatalytic activity,” comments Luo.

To demonstrate the efficiency of these catalysts, the researchers studied how they decomposed the dye rhodamine B in water. Within four hours of exposure to visible light 92 per cent of the dye was gone, which is much faster than conventional catalysts that lack gold nanoparticles.

These microparticles can also be used for water splitting, says Luo. The team showed that the microparticles with gold nanoparticles performed better in water-splitting experiments than those without, further highlighting the versatility and effectiveness of these microspheres.

The researchers have provided an illustration of the process,

Improved photocatalyst microparticles containing gold nanoparticles can be used to purify water. © 2014 A*STAR Institute of Materials Research and Engineering

Improved photocatalyst microparticles containing gold nanoparticles can be used to purify water.
© 2014 A*STAR Institute of Materials Research and Engineering

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

Novel Au/La-SrTiO3 microspheres: Superimposed Effect of Gold Nanoparticles and Lanthanum Doping in Photocatalysis by Guannan Wang, Pei Wang, Dr. He-Kuan Luo, and Prof. T. S. Andy Hor. Chemistry – An Asian Journal Volume 9, Issue 7, pages 1854–1859, July 2014. Article first published online: 9 MAY 2014 DOI: 10.1002/asia.201402007

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This article is behind a paywall.

Gold nanorod instabilities

A Dec. 8, 2014 news item on Nanowerk focuses on research from Australia,

Researchers at Swinburne University of Technology [Melbourne, Australia]  have discovered an instability in gold nanoparticles that is critical for their application in future technology.

Gold nanorods are important building blocks for future applications in solar cells, cancer therapy and optical circuitry.

However their stability is under question due to their peculiar reshaping behaviour below melting points.

A Dec. 8, 2014 Swinburne University of Technology press release, which originated the news item, discusses melting points and shape instabilities in the context of this research,

A solid normally does not change its shape unless it reaches its melting point, or surface melting points. It is also known that the melting point for nanoparticles is suppressed due to their size.

PhD student Adam Taylor (now a postdoctoral researcher at Swinburne) said it came as a surprise that reshaping is observed well below these melting points. Until now, no one could explain this peculiar behaviour.

“In our work, we have discovered both theoretically and experimentally that the reshaping mechanism for nanoparticles below melting point is surface atom diffusion, rather than melting,” Mr Taylor said.

Surface atom diffusion is a process involving the motion of molecules at solid material surfaces that can generally be thought of in terms of particles jumping between adjacent adsorption sites on a surface.

“Surface atom diffusion always existed in bulk solids, but this is the first evidence that its effect is enhanced at the nano-size, dominating over the traditional theory of melting,” Associate Professor James Chon, who is supervising Mr Taylor’s research, said.

Mr Taylor said the more finely nanoparticles are shaped, the less stable they become.

“This is important, for example, for solar panel manufacturers as the more needle-like these nanoparticles are shaped the less stable they become. If you put these particles into a solar panel to concentrate light they may not last long in the sun before they degrade,” Mr Taylor said.

“This discovery will be crucial for future applications of gold nanorods, as people will need to reconsider their stability when applying them to solar cells, cancer therapeutic agents and optical circuitry.”

The researchers have provided an illustration of their work,

Courtesy Swinburne University of Technology

Courtesy Swinburne University of Technology

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

Below Melting Point Photothermal Reshaping of Single Gold Nanorods Driven by Surface Diffusion by Adam B. Taylor, Arif M. Siddiquee, and James W. M. Chon. ACS Nano, Article ASAP DOI: 10.1021/nn5055283 Publication Date (Web): November 18, 2014

Copyright © 2014 American Chemical Society

This paper is behind a paywall but should you be in Australia and eligible to attend, there’s another opportunity to learn more; Taylor will be presenting his work at the Australian Institute of Physics conference on December 10, 2014 in Canberra.

Nano and stem cell differentiation at Rutgers University (US)

A Nov. 14, 2014 news item on Azonano features a nanoparticle-based platform for differentiating stem cells,

Rutgers University Chemistry Associate Professor Ki-Bum Lee has developed patent-pending technology that may overcome one of the critical barriers to harnessing the full therapeutic potential of stem cells.

A Nov. 1, 2104 Rutgers University news release, which originated the news item, describes the challenge in more detail,

One of the major challenges facing researchers interested in regenerating cells and growing new tissue to treat debilitating injuries and diseases such as Parkinson’s disease, heart disease, and spinal cord trauma, is creating an easy, effective, and non-toxic methodology to control differentiation into specific cell lineages. Lee and colleagues at Rutgers and Kyoto University in Japan have invented a platform they call NanoScript, an important breakthrough for researchers in the area of gene expression. Gene expression is the way information encoded in a gene is used to direct the assembly of a protein molecule, which is integral to the process of tissue development through stem cell therapeutics.

Stem cells hold great promise for a wide range of medical therapeutics as they have the ability to grow tissue throughout the body. In many tissues, stem cells have an almost limitless ability to divide and replenish other cells, serving as an internal repair system.

Transcription factor (TF) proteins are master regulators of gene expression. TF proteins play a pivotal role in regulating stem cell differentiation. Although some have tried to make synthetic molecules that perform the functions of natural transcription factors, NanoScript is the first nanomaterial TF protein that can interact with endogenous DNA. …

“Our motivation was to develop a highly robust, efficient nanoparticle-based platform that can regulate gene expression and eventually stem cell differentiation,” said Lee, who leads a Rutgers research group primarily focused on developing and integrating nanotechnology with chemical biology to modulate signaling pathways in cancer and stem cells. “Because NanoScript is a functional replica of TF proteins and a tunable gene-regulating platform, it has great potential to do exactly that. The field of stem cell biology now has another platform to regulate differentiation while the field of nanotechnology has demonstrated for the first time that we can regulate gene expression at the transcriptional level.”

Here’s an image illustrating NanoScript and gold nanoparticles,

Courtesy Rutgers University

Courtesy Rutgers University

The news release goes on to describe the platform’s use of gold nanoparticles,

NanoScript was constructed by tethering functional peptides and small molecules called synthetic transcription factors, which mimic the individual TF domains, onto gold nanoparticles.

“NanoScript localizes within the nucleus and initiates transcription of a reporter plasmid by up to 30-fold,” said Sahishnu Patel, Rutgers Chemistry graduate student and co-author of the ACS Nano publication. “NanoScript can effectively transcribe targeted genes on endogenous DNA in a nonviral manner.”

Lee said the next step for his research is to study what happens to the gold nanoparticles after NanoScript is utilized, to ensure no toxic effects arise, and to ensure the effectiveness of NanoScript over long periods of time.

“Due to the unique tunable properties of NanoScript, we are highly confident this platform not only will serve as a desirable alternative to conventional gene-regulating methods,” Lee said, “but also has direct employment for applications involving gene manipulation such as stem cell differentiation, cancer therapy, and cellular reprogramming. Our research will continue to evaluate the long-term implications for the technology.”

Lee, originally from South Korea, joined the Rutgers faculty in 2008 and has earned many honors including the NIH Director’s New Innovator Award. Lee received his Ph.D. in Chemistry from Northwestern University where he studied with Professor Chad. A. Mirkin, a pioneer in the coupling of nanotechnology and biomolecules. Lee completed his postdoctoral training at The Scripps Research Institute with Professor Peter G. Schultz. Lee has served as a Visiting Scholar at both Princeton University and UCLA Medical School.

The primary interest of Lee’s group is to develop and integrate nanotechnologies and chemical functional genomics to modulate signaling pathways in mammalian cells towards specific cell lineages or behaviors. He has published more than 50 articles and filed for 17 corresponding patents.

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

NanoScript: A Nanoparticle-Based Artificial Transcription Factor for Effective Gene Regulation by Sahishnu Patel, Dongju Jung, Perry T. Yin, Peter Carlton, Makoto Yamamoto, Toshikazu Bando, Hiroshi Sugiyama, and Ki-Bum Lee. ACS Nano, 2014, 8 (9), pp 8959–8967 DOI: 10.1021/nn501589f Publication Date (Web): August 18, 2014
Copyright © 2014 American Chemical Society

This paper is behind a paywall.

Faster, cheaper, and just as good—nanoscale device for measuring cancer drug methotrexate

Lots of cancer drugs can be toxic if the dosage is too high for individual metabolisms, which can vary greatly in their ability to break drugs down. The University of Montréal (Université de Montréal) has announced a device that could help greatly in making the technology to determine toxicity in the bloodstream faster and cheaper according to an Oct. 27, 2014 news item on Nanowerk,

In less than a minute, a miniature device developed at the University of Montreal can measure a patient’s blood for methotrexate, a commonly used but potentially toxic cancer drug. Just as accurate and ten times less expensive than equipment currently used in hospitals, this nanoscale device has an optical system that can rapidly gauge the optimal dose of methotrexate a patient needs, while minimizing the drug’s adverse effects. The research was led by Jean-François Masson and Joelle Pelletier of the university’s Department of Chemistry.

An Oct. 27, 2014 University of Montréal news release, which originated the news item, provides more specifics about the cancer drug being monitored and the research that led to the new device,

Methotrexate has been used for many years to treat certain cancers, among other diseases, because of its ability to block the enzyme dihydrofolate reductase (DHFR). This enzyme is active in the synthesis of DNA precursors and thus promotes the proliferation of cancer cells. “While effective, methotrexate is also highly toxic and can damage the healthy cells of patients, hence the importance of closely monitoring the drug’s concentration in the serum of treated individuals to adjust the dosage,” Masson explained.

Until now, monitoring has been done in hospitals with a device using fluorescent bioassays to measure light polarization produced by a drug sample. “The operation of the current device is based on a cumbersome, expensive platform that requires experienced personnel because of the many samples that need to be manipulated,” Masson said.

Six years ago, Joelle Pelletier, a specialist of the DHFR enzyme, and Jean-François Masson, an expert in biomedical instrument design, investigated how to simplify the measurement of methotrexate concentration in patients.

Gold nanoparticles on the surface of the receptacle change the colour of the light detected by the instrument. The detected colour reflects the exact concentration of the drug in the blood sample. In the course of their research, they developed and manufactured a miniaturized device that works by surface plasmon resonance. Roughly, it measures the concentration of serum (or blood) methotrexate through gold nanoparticles on the surface of a receptacle. In “competing” with methotrexate to block the enzyme, the gold nanoparticles change the colour of the light detected by the instrument. And the colour of the light detected reflects the exact concentration of the drug in the blood sample.

The accuracy of the measurements taken by the new device were compared with those produced by equipment used at the Maisonneuve-Rosemont Hospital in Montreal. “Testing was conclusive: not only were the measurements as accurate, but our device took less than 60 seconds to produce results, compared to 30 minutes for current devices,” Masson said. Moreover, the comparative tests were performed by laboratory technicians who were not experienced with surface plasmon resonance and did not encounter major difficulties in operating the new equipment or obtaining the same conclusive results as Masson and his research team.

In addition to producing results in real time, the device designed by Masson is small and portable and requires little manipulation of samples. “In the near future, we can foresee the device in doctors’ offices or even at the bedside, where patients would receive individualized and optimal doses while minimizing the risk of complications,” Masson said. Another benefit, and a considerable one: “While traditional equipment requires an investment of around $100,000, the new mobile device would likely cost ten times less, around $10,000.”

For those who prefer to read the material in French here’s a link to ‘le 27 Octobre 2014 communiqué de nouvelles‘.

Here’s a prototype of the device,

Les nanoparticules d’or situées à la surface de la languette réceptrice modifient la couleur de la lumière détectée par l’instrument. La couleur captée reflète la concentration exacte du médicament contenu dans l’échantillon sanguin. Courtesy  Université de Montréal

Les nanoparticules d’or situées à la surface de la languette réceptrice modifient la couleur de la lumière détectée par l’instrument. La couleur captée reflète la concentration exacte du médicament contenu dans l’échantillon sanguin. Courtesy Université de Montréal

There is no indication as to when this might come to market, in English  or in French.

Gold nanorods and mucus

Mucus can kill. Most of us are lucky enough to produce mucus appropriate for our bodies’ needs but people who have cystic fibrosis and other kinds of lung disease suffer greatly from mucus that is too thick to pass easily through the body. An Oct. 9, 2014 Optical Society of America (OSA) news release (also on EurekAlert) ‘shines’ a light on the topic of mucus and viscosity,

Some people might consider mucus an icky bodily secretion best left wrapped in a tissue, but to a group of researchers from the University of North Carolina at Chapel Hill, snot is an endlessly fascinating subject. The team has developed a way to use gold nanoparticles and light to measure the stickiness of the slimy substance that lines our airways.  The new method could help doctors better monitor and treat lung diseases such as cystic fibrosis and chronic obstructive pulmonary disease.

“People who are suffering from certain lung diseases have thickened mucus,” explained Amy Oldenburg, a physicist at the University of North Carolina at Chapel Hill whose research focuses on biomedical imaging systems. “In healthy adults, hair-like cell appendages called cilia line the airways and pull mucus out of the lungs and into the throat. But if the mucus is too viscous it can become trapped in the lungs, making breathing more difficult and also failing to remove pathogens that can cause chronic infections.”

Doctors can prescribe mucus-thinning drugs, but have no good way to monitor how the drugs affect the viscosity of mucus at various spots inside the body. This is where Oldenburg and her colleagues’ work may help.

The researchers placed coated gold nanorods on the surface of mucus samples and then tracked the rods’ diffusion into the mucus by illuminating the samples with laser light and analyzing the way the light bounced off the nanoparticles. The slower the nanorods diffused, the thicker the mucus. The team found this imaging method worked even when the mucus was sliding over a layer of cells—an important finding since mucus inside the human body is usually in motion.

“The ability to monitor how well mucus-thinning treatments are working in real-time may allow us to determine better treatments and tailor them for the individual,” said Oldenburg.

It will likely take five to 10 more years before the team’s mucus measuring method is tested on human patients, Oldenburg said. Gold is non-toxic, but for safety reasons the researchers would want to ensure that the gold nanorods would eventually be cleared from a patient’s system.

“This is a great example of interdisciplinary work in which optical scientists can meet a specific need in the clinic,” said Nozomi Nishimura, of Cornell University … . “As these types of optical technologies continue to make their way into medical practice, it will both expand the market for the technology as well as improve patient care.”

The team is also working on several lines of ongoing study that will some day help bring their monitoring device to the clinic. They are developing delivery methods for the gold nanorods, studying how their imaging system might be adapted to enter a patient’s airways, and further investigating how mucus flow properties differ throughout the body.

This work is being presented at:

The research team will present their work at The Optical Society’s (OSA) 98th Annual Meeting, Frontiers in Optics, being held Oct. 19-23 [2014] in Tucson, Arizona, USA.

Presentation FTu5F.2, “Imaging Gold Nanorod Diffusion in Mucus Using Polarization Sensitive OCT,” takes place Tuesday, Oct. 21 at 4:15 p.m. MST [Mountain Standard Time] in the Tucson Ballroom, Salon A at the JW Marriott Tucson Starr Pass Resort.

People with cystic fibrosis tend to have short lives (from the US National Library of Medicine MedLine Plus webpage on cystic fibrosis),

Most children with cystic fibrosis stay in good health until they reach adulthood. They are able to take part in most activities and attend school. Many young adults with cystic fibrosis finish college or find jobs.

Lung disease eventually worsens to the point where the person is disabled. Today, the average life span for people with CF who live to adulthood is about 37 years.

Death is most often caused by lung complications.

I hope this work proves helpful.

Fishnet of gold atoms improves solar cell performance

Apparently they’re calling the University of Western Ontario by a new name, Western University. Given the university’s location in what is generally acknowledged as central Canada or, sometimes, as eastern Canada, this seems like a geographically confusing approach not only in Canada but elsewhere too. After all, more than one country boasts a ‘west’.

A Sept. 26, 2014 news item on Nanowerk highlights new work on improving solar cell performance (Note: A link has been removed),

Scientists at Western University [Ontario, Canada] have discovered that a small molecule created with just 144 atoms of gold can increase solar cell performance by more than 10 per cent. These findings, published recently by the high-impact journal Nanoscale (“Tessellated gold nanostructures from Au144(SCH2CH2Ph)60 molecular precursors and their use in organic solar cell enhancement”), represent a game-changing innovation that holds the potential to take solar power mainstream and dramatically decrease the world’s dependence on traditional, resource-based sources of energy, says Giovanni Fanchini from Western’s Faculty of Science.

For those of us who remember ‘times tables’, the number 144 can have a special meaning as it is the last number (’12’ times ’12’ equals ‘144’) one was obliged to memorize. At least, that was true at my school in Vancouver, Canada but perhaps not elsewhere, eh?

Getting back to the ‘fishnet’, a Sept. 25, 2014 Western University news release, which originated the news item, expands the business possibilities for this work,

Fanchini, the Canada Research Chair in Carbon-based Nanomaterials and Nano-optoelectronics, says the new technology could easily be fast-tracked and integrated into prototypes of solar panels in one to two years and solar-powered phones in as little as five years.

“Every time you recharge your cell phone, you have to plug it in,” says Fanchini, an assistant professor in Western’s Department of Physics and Astronomy. “What if you could charge mobile devices like phones, tablets or laptops on the go? Not only would it be convenient, but the potential energy savings would be significant.”

The Western researchers have already started working with manufacturers of solar components to integrate their findings into existing solar cell technology and are excited about the potential.

“The Canadian business industry already has tremendous know-how in solar manufacturing,” says Fanchini. “Our invention is modular, an add-on to the existing production process, so we anticipate a working prototype very quickly.”

The news release then gives a few technical details,

Making nanoplasmonic enhancements, Fanchini and his team use “gold nanoclusters” as building blocks to create a flexible network of antennae on more traditional solar panels to attract an increase of light. While nanotechnology is the science of creating functional systems at the molecular level, nanoplasmonics investigates the interaction of light with and within these systems.

“Picture an extremely delicate fishnet of gold,” explains Fanchini explains, noting that the antennae are so miniscule they are unseen even with a conventional optical microscope. “The fishnet catches the light emitted by the sun and draws it into the active region of the solar cell.”

According to Fanchini, the spectrum of light reflected by gold is centered on the yellow colour and matches the light spectrum of the sun making it superior for such antennae as it greatly amplifies the amount of sunlight going directly into the device.

“Gold is very robust, resilient to oxidization and not easily damaged, making it the perfect material for long-term use,” says Fanchini. “And gold can also be recycled.”

It has been known for some time that larger gold nanoparticles enhance solar cell performance, but the Western team is getting results with “a ridiculously small amount” – approximately 10,000 times less than previous studies, which is 10,000 times less expensive too.

I hope to hear about a working prototype soon. Meanwhile, here’s a link to and a citation for the paper,

Tessellated gold nanostructures from Au144(SCH2CH2Ph)60 molecular precursors and their use in organic solar cell enhancement by Reg Bauld, Mahdi Hesari, Mark S. Workentin, and Giovanni Fanchini. Nanoscale, 2014,6, 7570-7575 DOI: 10.1039/C4NR01821D
First published online 06 May 2014

This paper is behind a paywall.

One final comment, it seems like a long lead time between publication of the paper and publicity. I wonder if the paper failed to get notice in May 2014, assuming there was a campaign at the time, or if this is considered a more optimal time period for getting noticed.