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Tag Archives: Carbon Nanotubes

Progress in the Commercialization of Graphene

European Plastics News posted an article on it’s site last week,("Graphene developers seek routes out of the lab"), focusing on challenges to and progress in the commercialization of graphene, specifically its "potential as a mutlifunctional reinforcement in composites".

Among the challenges the article raises are:

1) Entangling of 3D carbon nanotubes (CNTS) bundles

2) Individual graphite sheets restacking themselves

3) Handling of such shets during transportation to processing facilities

4) Reduction of costs of production and transportation

5) A need to develop standard operating procedures for potential health hazards

While these challenges may seem daunting, the success of three companies – Vorbeck Materials of Maryland,Cabot Corporation of Massachusetts, and Thomas Swan & Co., based in the United Kingdom – are highlighted.

The article also discusses the ongoing support of  the European Commission (EC) and the UK’s government of research in graphene and how to commercialize it.:

The European Commission is planning to channel €1bn over 10 years into co-ordinated graphene research and commercialisation. The UK government has announced it wants to spend another £50m (€60.7m) to keep the UK at the forefront of graphene research, with the University of Manchester set to host a national institute of graphene research. Commercialisation of graphene by this route could arrive by late 2012.

Converted in US dollars, the EC will be spending $1.278 billion and the UK $78.153 million.…

The NanoRelease Project

The January 23, 2012 issue of Bloomberg BNA’s Daily Environment Report carried an article (Repoduced with permission from Daily Environment Report, 13 DEN A-11, 1/23/2012. Copyright -2012 by the Bureau of National Affairs, Inc (800-372-1033 http://www/bna.com) "Government, Industry, advocacy Groups Work on Carbon Nanotube Release Measures" that focused on the work of the NanoRelease Project. As noted on its website, the NanoRelease Project’s purpose is to "foster the safe development of nanomaterials by supporting development of methods to understand the release of nanomaterials used in products."

Objectives:

  • Provide focus to broad policy debates by working through scenarios under which specific engineered nanomaterials might be released from products;

  • Examine the full life cycle of products that might act to release nanomaterials;

  • Catalogue and disseminate published and unpublished data and methods (that meet minimum criteria) used to evaluate release scenarios;
  • Develop “state of the science” reports about release measurement for the specific material types chosen that describe what is known and what research gaps exist; and
  • Enable improvements, standardization, and widespread use of methods by carrying out tests using reference nanomaterial-matrix and positive controls in a “round robin” or similar approach.

The NanoRelease Project is overseen by a Steering Committee composed of "Government officials, chemical manufacturers, and representives of labor and consumer advocacy groups." Among the members of the Steering Committee is John Monica, Jr, a partner in the DC office of Porter, Wright, Morris & Arthur LLP.

As the article notes, Carbon Nanotubes (CNTs) are currently incorporated into a …

New Nanoscale Carbon Website — CNT Report

Readers may be interested in learning about a new subscription website devoted to nanoscale carbon — CNT Report

CNT Report is dedicated to bringing its readers the most recent news concerning important issues affecting nanoscale carbon research, development, and commercialization.  CNT Report closely covers all forms of nanoscale carbon in development on the global stage, including CNTs, graphene, fullerenes, specialty fibers, and all else in-between.  CNT Report’s primary focus is on new scientific research developments, practical applications, finance, legal and regulatory issues, and general commercialization.   CNT Report publishes news in several broad categories including: Business, Commercialization,  Finance & Deals, Insurance, Intellectual Property, International Laws & Regulations, Policy, Standards, States, Science, Applications, Current Research, and Environmental, Health and Safety.

CNT Report also accepts press releases, research results, financial news, or any other news item related to nanoscale carbon which it then makes available to all of its subscribers.  CNT Report welcomes timely contributions from its readers and makes sure that their articles receive proper attribution and credit.

 …

EPA to Issue New Carbon Nanotube Significant New Use Rule

Here is an advance copy of a new multi-walled carbon nanotube significant new use rule being published tomorrow in the federal register.  It applies only to the specific carbon nanotubes that were the subject of PMN P-08-199, and binds anyone who intends to manufacture, import, or process the specific chemical substance.  It is largely consistent with past SNURs and Consent Orders for other CNTs.  For those wondering, "processors" and "processing" is broadly defined under TSCA.  It has been used in the past to include repackaging for commercial purposes, using the material in the manufacturing of new mixtures, and/or the production of articles using the substance.…

NIOSH Recommends Exposure Limit of 7 μg/m 3 for Carbon Nanotubes

This article originally appeared on the National Nanomanufacturing Network’s InterNano website. It is licensed under Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported.

In late November, the National Institute for Occupational Safety and Health (NIOSH) published a Current Intelligence Bulletin entitled "Occupational Exposure to Carbon Nanotubes and Nanofibers." The document is not an official "agency determination or policy," and was released solely by NIOSH for peer-review and comment. NIOSH’s carbon nanotube recommended exposure limit (CNT REL) is set at 7 μg/m 3 for these preliminary purposes.

The old saying that "a picture is worth a thousand words" is once again proved by the document’s cover image which is a remarkable "field emission micrograph of a multi-walled carbon nanotube…penetrating the pleura of the lung." The finely detailed image of a CNT penetrating a lung membrane should cause any reader to stop and closely consider the document’s recommendations.

The document begins by noting that while there are no scientific reports of "adverse health effects in workers producing or using carbon nanotubes…or carbon nanofibers," NIOSH is concerned because some studies have shown that the potential for worker exposure exists. Additionally, some in vivo studies have shown adverse reactions to carbon nanotubes in rodents — including pulmonary inflammation and fibrosis. Further, some in vitro and in vivo studies have led researchers to theorize that inhalation of certain carbon nanotubes in large doses may potentially cause asbestos-type exposure effects.

NIOSH explains that the scientific basis for its CNT REL is an extrapolation from subchronic in vivo toxicity studies …

Webinar: The Rise of MWNTs

On July 20, 2010, David Hwang of Lux Research gave a webinar entitled: "Lux Research Nanomaterials: The Rise of MWNTs: Oversupply Hides Real Opportunities."

Mr. Hwang’s presentation identified the top global producers of multi-walled carbon nanotubes (MWCNTs), explained why commercialization over the past 25 years has been relatively "anemic," and made some predictions for where the market is heading in the next decade. He explained that while total sales of MWCNTs were under $100 million for 2008, the market is predicted to grow to approximately 2389 tons by 2020.

Two major forces slowing past commercialization included (i) a "you first" mentality by which companies wanted to see others take the first successful steps towards commercialization before they joined the trend, and (ii) regulatory risks inherent in the development of any new technology — a commercialization bottleneck related to the potential environmental, health, and safety (EHS) impacts of certain carbon nanotubes.  (Regular readers will note that this is a recurring theme in our articles).

Mr. Hwang further explained that he believes the market for MWCNTs is currently in a transition phase, and that an oversupply will exist until 2017.  He commented that total sales in 2009 equaled $75 million and would increase to $513 million by 2020.   Mr. Hwang then covered four specific markets that are leading the commercialization for MWCNTs and provided 2009 versus 2020 material usage estimates:

 

  • Sporting goods: 4 tons (2009) versus 270 tons (2020)
  • Aerospace/defense: less than 1 ton (2009) versus 67 tons (2020)
  • Wind turbines: 130

Nanotubes in Space

Space, the final frontier.

Captains James T. Kirk and Jean-Luc Picard

One of the most significant challenges facing NASA in the development of the next generation of vehicle to replace the aging Space Shuttles and carry astronauts back to the Moon and the International Space Station (and beyond) is weight. The less a vehicle weighs, the more it can conserve on fuel. NASA is now looking into the possibility of using carbon nanotubes in the construction of the Orion Crew Exploration Vehicle and future spacecraft. By using carbon nanotubes, NASA estimates that the weight of Orion and other vessels could be reduced by up to 50%.

In order to achieve efficient and consistent production of carbon nanotubes at a reasonable cost, NASA has been working with the private sector, awarding Phase I and Phase II Small Business Innovation Research Contracts to SouthWest Nanotechnologies, Inc of Norman OK. Using these research contracts, SWeNT has been able to develop production methods that produce consistent high quality CNTs at lower cost. In turn, this has lead to increased business from other companies for CNTs to be used in a variety of products, including body and vehicle armor for use in Iraq and Afghanistan, where it replaces Kevlar.

Those readers who grew up watching and following the Apollo lunar missions and can still recall where they were and what they were doing when Neil Armstrong stepped onto the Moon’s surface, may also recall the wide range of spin-offs from government sponsored technology that made their way into …

Selected Short Subjects

Prize Winners

The Foresight Institute recently announced that Dr. Oscar Custance of the National Institute for Materials Science in Japan and Professors Yoshiaki Sugimoto and Masayuki Abe of Osaka University, are the co-winners of the Feynman Prize for Experimental Work in Nanotechnology. The Feynman Prize was named after Richard Feynman and are awarded to researchers whose work "has most advanced the field toward the achievement of Feynman’s vision for Nanotechnology". The prizes will be awarded in January 2010.

Dr Elena Shevchenko, of the Argonne National Laboratory, has been selected by Technology Review as one of the top 35 innovators under the age of 35. Dr. Shevchenko was cited for her work developing nanocrystals that could be used in the production of more efficient solar cells, more powerful magnets and faster processing computers.

Carbon Nanotubes and Buses of the Future

Recently at American University in DC Sinautec Automotive Technologies of Arlington Virginia presented a "Zero Carbon Ultracapacitor Bus" to the public. The electric powered buses use a carbon nanotube enhanced ultracapacitor to store more electricity, decreasing the time for recharging and increasing the distance the bus can travel from one stop to another. Aside from being less expensive than diesel fueled buses, Dan Ye, the executive director of Sinautec, estimated that the use of such buses would reduce carbon emissions by 70%. the buses are a common sight in cities in the Peoples Republic of China and Sinautec Automotive Technologies is partnering with scientists at MIT and the Stella Group …

Fruit Flies And Carbon Nanotubes

Environmental Science And Technology recently published online an article, "Differential Toxicity of Carbon Nanotubes in Drosophila: Larval Dietary Uptake is Benign, but Adult Exposure Causes Locomotor Impairment and Mortality", by Xinyuan Liu and a team of scienticists from the Chemistry, Engineering, Ecology and Evolutionary Biology Departments and the Institute for Molecular and Nanoscale Innovation of Brown University, that examined reactions to exposure to carbon nanotubes (cnts) in the larval and adult stages of the common fruit fly.

The experiments showed that fruit fly larvae, exposed to cnts since the time of their hatching could absorb and sequester the cnts in their bodily tissues no no evident toxic side effects, even at concentrations of cnts that were four times greater than what they would have encountered in a "normal" environment.

Adult fruit flies, on the other hand, were not so fortunate when exposed to powdered forms of nanoparticles, with effects ranging from a loss of the ability to climb out of a test tube, due to the nanoparticles adhering to the fruit flies feet,  to death. At lower levels of concentration and exposure, nanoparticles were found to be transmitted to unexposed adult flies via fly-to-fly contact and grooming behaviors.

Noting that flies have acted as disease vectors throughout human history, the authors note that

In the environment, such transport and redeposition may bring nanoparticles into contract with humans or environmental receptors that would not otherwise be exposed.

As nanoindustries begin to expand and new factories built or old ones converted to …

EPA Issues Clarification Regarding Carbon Nanotube SNURs

Readers may interested in learning that EPA issued a clarification today regarding its single-walled and multi-walled carbon nanotube SNURs previously issued in June 2009. EPA’s announcement follows.  Stay tuned . . .

Good afternoon.  On June 24, 2009, the U.S. EPA issued final Significant New Use Rules (SNURs) under the Toxic Substances Control Act (TSCA) for 23 new chemicals, including two carbon nanotubes (nanoscale materials) (http://www.epa.gov/fedrgstr/EPA-TOX/2009/June/Day-24/t14780.pdf).  The SNURs will allow the commercialization of these specific carbon nanotubes under limited conditions to protect against unreasonable risks to human health and the environment.  

The SNURs require companies to notify EPA at least 90 days before manufacture, import, or processing of the specific carbon nanotubes for any activity not meeting the conditions specified in the rules at 40 C.F.R. 721.10155  and 40 C.F.R. 721.10156.

Upon reviewing the rules some stakeholders have asked EPA whether these SNURs apply to all variants of carbon nanotubes. This is not the case. These SNURs only apply to the specific carbon nanotubes that were the subject of the premanufacture notices (PMNs) submitted under Section 5 of TSCA and not to any other carbon nanotubes.  Other carbon nanotubes must be notified through EPA’s New Chemicals Program.   The U.S. EPA strongly encourages all manufacturers and importers of nanoscale materials that are intended for commercial use to consult with the Agency in advance of production or importation.

If you have any questions, please contact:

Zofia Kosim (202-564-8733) or kosim.zofia@epa.gov Jim Alwood (202-564-8974) or alwood.jim@epa.gov ——————————————————————– David E. Giamporcaro …

EPA Issues Significant New Use Rules for Multi-Walled and Single-Walled Carbon Nanotubes

In the June 24, 2009 federal register, the U.S. Environmental Protection Agency (EPA) issued two proposed Significant New Use Rules (SNUR) under Section 5(a) of the Toxic Substances Control Act (TSCA) for multi-walled and single walled carbon nanotubes.  The SNURs followed up on the EPA’s prior September 2008 consent orders entered into with Thomas Swan & Co. Ltd. (Swan) for two of its Elicarb carbon nanotube products.

Under TSCA, the prior September 2008 consent orders were only binding on Swan.  "Consequently, after signing a Section 5(e) Consent Order, EPA generally promulgates a Significant New Use Rule (SNUR) that mimics the Consent Order to bind all other manufacturers and processors to the terms and conditions contained in the Consent Order.  The SNUR requires that manufacturers, importers and processors of certain substances notify EPA at least 90 days before beginning any activity that EPA has designated as a "significant new use. These new use designations are typically those activities prohibited by the Section 5(e) Consent Order."

Under the terms of the Septmeber 2008 consent orders which are incorporated into the new proposed SNURs, significant new uses of multi-walled and singled-walled carbon nanotubes are deemed to occur when employees do not “use gloves impervious to nanoscale particles and chemical protective clothing;” and/or fail to “use a NIOSH-approved full-face respirator with an N-100 cartridge while exposed by inhalation in the work area.”

Thus, the new proposed SNURs require these same conditions.

Manufacturers should also be aware that the EPA considers carbon nanotubes new chemical

Are Nanoparticles Released by Compounding or the Cutting of Nano-Composites?

Perhaps the most overlooked issue when examining potential nano-related environmental, health, and safety concerns is whether there is any true likelihood of exposure in reasonably foreseeable use scenarios.  While there should continue to be extensive toxicity testing for certain nanoscale materials, the most interesting research (from my perspective) relates to potential workplace and/or condumer exposure in realistic settings.  We examine two studies along these lines below.

C. Su-Jung et al., "Control of Airborne Nanoparticles Releases During Compounding of Polymer Nanocomposites," 3 Nano: Brief Reports and Reviews 4, 301 – 309 (2008).

This study was conducted by researchers at the National Science Foundation-funded Center for High-Rate Nanomanufacturing at the University of Massachusetts at Lowell.  The scientists examined potential nanoparticle release related to the twin-screw extruder compounding of polymer nanocomposites.  The test was conducted because "commercial compounding (mixing) of nanocomposites is typically achieved by feeding the nanoparticles and polymer into a twin-screw extruder, the airborne particles associated with nanoparticles reinforcing agents are of particular concern, as they can readily enter the body through inhalation."

The nanoparticles in question were nano aluminum oxide particles acquired from Nanophase Technologies in commercially available form.  The particles were spherical in shape and ranged from 27 to 53 nm in diameter.  They were also specifically "engineered to form agglomerates with a nominal size of 200 nm."

Regarding the test itself, the scientists fed 2.3kg of polymer pellets and 0.16 kg of nano-alumina particles into a twin-screw extruder for processing and then measured potential nanoparticle release through two measurement …

Carbon Nanotubes

The April issue of Environmental Health Perspectives carries a short article summarizing a seminar at the 2009 AAAS Annual Meeting titled "Driving Beyond Our Nano-Headlights?". In the summary, there is a brief reference to work done by Vanesa Sanchez, a graduate student at Brown University. The results of her experiment are rather alarming.

Ms. Sanchez work showed that

very low doses of CNTs . . . appeared to cause lesions known as granulomas similar to what occurs with asbestos fibers. Moreover, the CNTs formed a cage-like structure that . . .  might promote granuloma formation.

It is too bad that the summary didn’t give more space to a study that could have a profound effect on future nanomanufacturing facilities and possible future governmental regulation of the nano-industry.…

NIOSH Carbon Nanotube Data Request

In order to evaluate the possible health risks of occupational exposure to carbon nanotubes, the National Institute for Occupational Safety and Health (NIOSH) recently published a notice in the federal register requesting the submission of the following types of information from the public regarding carbon nanotubes:

  • Data from published and unpublished in vitro and in vivo toxicity studies;
  • Information regarding possible adverse health effects observed in workers exposed to carbon nanotubes;
  • Identification of workplaces using carbon nanotubes and information regarding potential exposure scenarios, exposure data, and exposure control measures used in such locations; and
  • Identification of products containing carbon nanotubes.

NIOSH notes that “[e]stimates of the number of workers potentially exposed to [carbon nanotubes] are unavailable due to limited exposure data and its relatively recent introduction into domestic commerce. The toxic nature of [single-walled carbon nanotubes] and [multi-walled carbon nanotubes] in humans is not known.”…

California Formally Requests Carbon Nanotube Information From Manufacturers

On January 22, 2009, California’s Department of Toxic Substances Control (DTSC) sent a formal request to several California manufacturers and/or importers of carbon nanotubes seeking information regarding analytical test methods, environmental fate and transport, and other relevant environmental, health, and safety information regarding carbon nanotubes.  The request was issued by DTSC under its authority granted under California’s Health and Safety Code 699, Sections 57018-57020.

DTSC asked manufacturers to answer the following questions:

What is the value chain for your company? For example, in what products are your carbon nanotubes used by others? In what quantities? Who are your major customers?

What sampling, detection and measurement methods are you using to monitor (detect and measure) the presence of your chemical in the workplace and the environment? Provide a full description of all required sampling, detection, measurement and verification methodologies. Provide full QA/QC protocol.

What is your knowledge about the current and projected presence of your chemical in the environment that results from manufacturing, distribution, use, and end-of-life disposal?

What is your knowledge about the safety of your chemical in terms of occupational safety, public health and the environment?

What methods are you using to protect workers in the research, development and manufacturing environment?

When released, does your material constitute a hazardous waste under California Health &Safety Code provisions? Are discarded off-spec materials a hazardous waste? Once discarded are the carbon nanotubes you produce a hazardous waste? What are your waste handling practices for carbon nanotubes?

Recipients have one year to supply the requested information.…

A Nano-Mesothelioma False Alarm

For those who are interested, below is the abstract of our new article published in the Fall edition of Nanotechnology Law & Business.   You can find the full edition here: www.nanolabweb.com

 

A Nano-Mesothelioma False Alarm

In May 2008, a scientific study (the “Poland Study”) was published in Nature Nanotechnology—which sparked a rash of popular media claims that like asbestos, exposure to carbon nanotubes may cause mesothelioma. In this article, a team led by lawyer John Monica evaluates the Poland Study in a potential litigation context to determine its significance, if any, in legally establishing that the inhalation of multiwalled carbon nanotubes (“MWCNTs”) causes mesothelioma. After first considering the reliability of the Poland Study’s design and execution, they conclude that it would not be admissible in a court of law because it fails Daubert standards. Specifically, they argue that: (i) the design and execution of the Poland Study are not generally accepted in the scientific community for the purposes offered; (ii) in order to reach the conclusion that inhalation of MWCNTs may cause mesothelioma, an expert would have to use the Poland Study in such a manner as to extrapolate from an accepted premise to an unfounded conclusion; and, (iii) the Study’s authors failed to adequately account for obvious alternative explanations (confounders), including surface chemistry, sample contamination, sample commingling, spontaneous formation of granulomas, and possible mouse colony infections.…

Carbon Nanotubes and TSCA Registrations

Today, US EPA issued a Federal Register notice stating the Toxic Substances Control Act (TSCA) registration requirements are "potentially applicable to carbon nanotubes."  EPA confirmed its position the CNTs are "chemical substances distinct from graphite or other allotropes of carbon listed on the TSCA inventory."  The bottom line is stated succinctly by EPA: "Many CNTs may therefore be new chemicals under TSCA Section 5."…

EPA Consent Order for Multi-Walled Carbon Nanotubes

Last month we reported on a press release by Thomas Swan & Co. Ltd. of the United Kingdom indicating the company had recently entered into a PMN consent order with the EPA under the Toxic Substances Control Act (“TSCA”) concerning one of its multi-walled carbon nanotube (MWCNT) products. Barring an unusual coincidence, it appears that EPA has recently published a redacted version of the Swan Consent order here.

The order makes it clear that the PMN was submitted pursuant to § 5(a)(1) of TSCA, and that it covers a MWCNT product. Additionally, the consent order places several requirements on the manufacturer. Specifically, the manufacturer is required to:

  1. Deliver 1 gram of the MWCNTs to EPA with a copy of MSDS for the product;
  2. Conduct “90 day inhalation toxicity study in rats with a post exposure; observation period of up to 3 months, including bronchoalveolar lavage fluid (“BALF”) analysis (OPPTS 870.3465 or OECD 413);
  3. Submit material characterization data within six months (see below);
  4. Ensure employees “use gloves impervious to nanoscale particles and chemical protective clothing;” and
  5. Ensure employees “use a NIOSH-approved full-face respirator with an N-100 cartridge while exposed by inhalation in the work area.”

Regarding the second requirement, the consent order also provides the manufacturer with an opportunity to submit toxicity testing data under the Agency’s new Nanoscale Material Stewardship Program as an alternative to the 90 day mouse inhalation test: “If, for example, a consortium of companies commit to testing a representative set of MWCNT for subchronic mammalian toxicity, …

Functionalize Carbon Nanotubes Deemed “Highly Biocompatible”

A February 2008 study published by six Stanford scientists examined the long term fate of intravenously injected carbon nanotubes in mice.   The scientists’ goal was to measure the circulation of SWCNTs in the bloodstream and to determine whether they accumulate in organs and/or tissues.  At the same time, the scientists also studied the effects of functionalizing SWCNTs with polymers.  They found that functionalizing the SWCNTs with polyethyleneglycol enabled full blood circulation in 1 day, yet there was little uptake by the liver and spleen.  Additionally, near complete clearance from main organs occurred in about two months through the excretion of urine and feces.  No toxic side effects were observed.   The authors further found that the SWCNTs became more biologically inert as they increased the number of functionalized polymer branches. 

The scientists concluded that this and other studies "provide a strong indication of the lack of toxicity of well functionalized SWNTs in mice before clearance from the body. In contrast to a previous study of nonfunctionalized pristine carbon nanotubes causing fiber toxicity to mice, our well functionalized SWNTs are highly biocompatible for in vivo applications."

Z. Liu, et al., "Circulation and long-term fate of functionalized, biocompatible single-walled carbon nanotubes in mice probed by Roman spectroscopy," PNAS, Vol. 105, No. 5 at 1410-1415 (February 5, 2008).  …

Media Rips Carbon Nanotubes

There have been a number of articles published since May 20 regarding a possible link between carbon nanotubes and the development of precursors of mesothelioma because of a recent letter published in Nature Nanotechnology.

C. Poland, et al., "Carbon nanotubes introduced into the abdominal cavity of mice show asbestos-like pathology in a pilot study," Nature Nanotechnology, May 20, 2008.

 …

New Genotoxicity Study on SWCNTs.

Eight scientists from NIOSH and two from Lockheed Martin recently published "Single-walled Carbon Nanotubes: Geno- and Cytotoxic Effects in Lung Fibroblast V79 Cells," in the Journal of Toxicology and Environmental Health, Part A, 70:2071-2079 (Dec. 15, 2007).  The authors claim the study is the first published research examining the potential genotoxic effects of cellular exposure to SWCNTs. The paper is summarized below.  …

Another MSDS Example for Multiwalled Carbon Nanotubes

For our readers who are interested, we are posting another MSDS from a producer of multiwalled carbon nanotubes.  We previously discussed the issue of what information nanomanufacturers are putting in their Material Safety Data Sheets here.

Plus, here is an added bonus MSDS from Cheaptubes where you can order various nanoparticles over the internet at discount prices.…

New Study On Detecting Carbon Nanotubes In Living Organisms

Researchers at Rice University successfully utilized a near-infrared flourescent imaging technique to detect individual carbon nanotubes in fruit flies.  The study, reported here and here, involved an experiment where the researchers fed fruit fly larvae a diet that contained carbon nanotubes.  The flies were then shot with a laser, which excited the nanotubes and allowed them to be viewed using a flourescent technique.   The good news is that the fruit flies apparently survived to adulthood just as well as fruit flies in the control group, and apparently weighed the same as the controls, too.  The study’s conclusions about the bioaccumulation of the nanotubes in the fruit flies are interesting:

When the researchers removed and examined tissues from the flies, they found the near-infrared microscope allowed them to see and identify individual nanotubes inside the tissue specimens. The highest concentration of nanotubes was found in the dorsal vessel, which is analogous to a main blood vessel in a mammal. Lesser concentrations were found in the brain, ventral nerve cord, salivary glands, trachea and fat. Based on their assays, the team estimates that only about one in 100 million nanotubes passed through the gut wall and became incorporated into the flies’ organs. 

I don’t know enough about the anatomy of a fruit fly to fully grasp the significance of these findings, but I find it hopeful that only a tiny fraction of the nanotubes accumulated in the flies’ organs, and also find it hopeful that the flies were apparently not harmed by the nanotubes’ presence.  One of the …

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