Nanotubes, Nanoshells, what are the consequences?
Carbon nanotubes and metal nanoshells
Nanotechnology, and particularly the manufacture of nanoparticles in custom forms are charging ahead with a vengeance but, says Dr. Mae-Wan Ho of the Institute of Science in Society, our understanding of possible adverse health and environmental effects is not keeping pace.
Carbon nanotubes are manufactured in great quantities and are expected to be used in quantities of hundreds of thousands of tons within the next 5 to 10 years, but if the particles become airborne, they may be destructive to our lungs on inhalation, similar to asbestos fibers, which had to be eliminated from building materials and other uses because of increased lung cancer risk.
Metal nanoshells are a class of nanoparticles with tunable resonance to electromagnetic radiation. They consist of a spherical dielectric core nanoparticle, such as silica, surrounded by a thin metal shell, such as gold. Although there are potential medical applications, it seems like neither long term health effects nor environmental effects have so far been addressed.
Mae-Wan Ho urges caution and calls for a moratorium on research and development until proper safeguards are put in place.
See also:
Nanotech Materials Can Damage Your Brain
Nanotubes Highly Toxic
An entire molecular electronics industry is poised to take off, much of it on the back of carbon nanotubes. But new research is raising alarm. Nanotubes are highly damaging to the lungs of mice. Dr. Mae-Wan Ho calls for a moratorium until proper safeguards can be put in place.
Molecular electronics is making headlines. Much of it is based on single-wall carbon nanotubes, which have many other potential applications as strong, lightweight material in the aerospace and defence industries. Nanotubes are now manufactured in bulk. Dr. Smalley (Nobel laureate and a pioneer in carbon nanotube research) predicted that hundreds of thousands of tons of the stuff could be produced in 5 to 10 years and "in time, millions of tonnes of nanotubes will be produced worldwide every year". But enthusiasm for research and development has run way ahead of safety precaution.
Unprocessed nanotubes are very light, and could become airborne and potentially reach the lungs. Researchers in the Space and Life Sciences of NASA Johnson Space Center, Wyle Laboratories, and the Department of Pathology and Laboratory Medicine, University of Texas Medical School, in Houston, Texas, USA, investigated the toxicity of carbon nanotubes to the lungs, by introducing them into the trachea of mice under anaesthesia.
The results are alarming. Five of the mice treated with high dose of one kind of nanotubes died within 7 days. All nanotube products induced epitheliod granulomas – tumour-like nodules of bloated white blood cells in the lining of the lungs - and in some cases inflammation of the lungs at 7 days. These persisted and became more pronounced in animals that were sacrificed at 90days. The lungs of some animals also showed inflammation around the bronchi, and extensive necrosis (tissue death).
Carbon nanotubes, the researchers conclude, are "much more toxic than carbon black and can be more toxic than quartz, which is considered a serious occupational health hazard in chronic inhalation exposures."
The researchers had used nanotubes produced under different conditions containing different heavy metals. Samples of ‘raw’ and ‘purified’ nanotubes both contained iron, while a third nanotube product contained nickel and yttrium.
A suspension containing 0, 0.1 or 0.5 mg of carbon nanotubes was introduced into the trachea of the mice. As added controls, groups of mice were given a suspension of carbon black or of quartz. The mice were killed at 7days or 90days after the single treatment, in order to examine the lungs.
Nanotubes are neither water-soluble nor wettable, and all the products were extremely difficult to disperse; and ultrasound as well as heat-inactivated mouse serum had to be used.
Graphite – the most similar form of carbon to nanotubes - does not possess the electrical properties and fibrous structure of the nanotubes, and its permissible inhalation exposure limit set by the occupational safety and health administration (OSHA) is 15mg/m 3of total dust and 5mg/m 3for the ‘respirable’ (capable of being inhaled) fractions. It is well known that the geometry and surface chemistry of particulates can play an important role in causing lung toxicity.
All animals treated with 0.1mg per mouse of nickel-yttrium containing nanotubes showed no overt clinical signs. But 5 of 9 mice treated with 0.5mg died: 2/4 within the 7day group and 3/5 in the 90day group. All deaths occurred 4 to 7 days after receiving the nanotubes. Deaths generally preceded by lethargy, inactivity and body-weight losses. These symptoms were also seen in the high dose mice that survived. Mice in the 90day group lost 27% of their body weight by the first week. Symptoms in the two surviving mice disappeared after one week and the animals started to gain weight.
The iron-containing nanotubes (both raw and purified) did not cause deaths in the mice. Mild signs of inactivity, hypothermia, and occasionally shivering were most noticeable 8 to 12h after treatment with the raw nanotubes, and symptoms disappeared soon after this time. There were no body weight losses with the raw or purified iron-containing nanotubes.
Under the microscope, the lungs of dead animals in the high dose group showed large aggregates of particles in macrophages (large white blood cells that ‘eat’ foreign particles) in the alveolar space (air sac), some of the aggregates were also found in spaces between cells, forming granulomas (tumour-like nodules consisting of the bloated white blood cells). There were also signs of inflammation. Granulomas were not detected in mice given the low dose of the nickel-yttrium nanotubes. The lungs of mice given high dose of either raw or purified iron-containing nanotubes showed prominent granulomas at 7days. Most of these nodules were located beneath the bronchial epithelium (lining) and were present throughout the lung fields. Some appeared to extend into the bronchi as polyps (irregular growths) .
The granulomas consisted of macrophages laden with black particles, and had very few other white blood cells. Some of the lungs from mice given high doses of the nanotubes appeared grossly abnormal at 90 days. The lung lesions were generally more pronounced than those given the high dose at 7 days; some also had necrosis (tissue death), and extensive inflammation. Granulomas and other pulmonary lesions were also seen in some of the mice given the lose doses of nanotubes, but to a milder degree.
Heat inactivated serum did not produce any clinical signs, nor gross or microscopic lesions. The mice of the carbon black or quartz treated controls also did not show any clinical signs that could be attributed to treatment. Quartz at high dose (0.5 mg) induced an increase in the number of macrophages in the lungs, and some of these cells contained particles. Quartz also produced mild to moderate inflammation. The results for the 7day and 90day groups were generally similar. One mouse in the 7day group had a low-grade granuloma reaction; and the mice in the high dose 90day group had increased clusters of lymphocytes surrounding the bronchi (sign of inflammation).
Purified nanotubes contained only a small amount of metal (2% by weight). Insoluble iron and iron compounds are low in toxicity, so the results strongly indicate that the nanotubes themselves induced the granulomas. Another research group had found similar results previously in rats.
The deaths of 5 mice may have been caused by nickel and yttrium in the nanotube sample, as they did not occur in the other samples of nanotubes.
One of the major effect of nanotubes is that they moved rapidly through the walls of the air sacs, in contrast to carbon black. Nanotubes are totally insoluble and non-biodegradable fibres, and it is well known that the pathogenicity of a fibre in the lungs directly correlates with its persistence.
Graphite toxicity is known as graphite pneumoconiosis, characterized by granulomas, emphysema, tissue death and hardening of the blood vessels, among other symptoms, and has been long recognized in a large number of workers involved in mining and processing graphite. But theses nanotube samples did not contain graphite.
These results show that a single exposure is enough to trigger serious effects including deaths. No safety tests have yet been carried out, especially in the longer-term, on a range of other nanoparticles used, some of them in intended medical procedures. Civil society watchdogs such as the ETC Group have called for a moratorium on nanotechnology research and development.
The present findings certainly justify a moratorium on research involving nanotubes, if not all nanoparticles, until proper safeguards can be put in place, and safety tests carried out in the meantime.
Source
Lam CW, James JLt, McCluskey R and Hunter RL. ToxSci Advance Access published 26, 2003. Pulmonary toxicity of single-wall carbon nanotubes in mice 7 and 90 days after intratracheal instillation.
(from the ISIS website)
Metal Nanoshells, Cure or Curse?
Among the nanoparticles developed for use in medical and other applications are non-biodegradable metal nanoshells. Has enthusiasm to exploit their remarkable properties run too far ahead of safety considerations? Dr. Mae-Wan Ho reports.
Metal nanoshells are a class of nanoparticles with tunable resonance to electromagnetic radiation. They consist of a spherical dielectric core nanoparticle, such as silica, surrounded by a thin metal shell, such as gold.These particles possess a highly tunable plasmon resonance‚ whereby light of particular frequencies causes collective oscillations of conductive metal electrons at the nanoshell surface, thus greatly concentrating the intensity of the light. Whereas many bulk metals demonstrate plasmon resonance behaviour, they do so generally over a very small region of the visible spectrum.
In nanoshells, however, their plasmon resonance can readily be tuned to a wide range of specific frequencies, from the near ultra violet to the mid-infra-red, simply by controlling the relative thickness of the core and shell layers of the nanoparticle. This range spans the near infrared, a region where absorption in tissue is minimal and penetration is optimal.
To date, nanoshells have demonstrated their usefulness in many applications ranging from inhibition of photo-oxidation in photoluminescent polymer films to biosensing and light-triggered drug delivery.
One possible application is in removing diseased tissues without complicated surgery. Recently, lasers, microwaves, radio-frequency radiation, and focused ultrasound, have all been used to heat up and kill diseased tissues selectively without invasive surgical procedures. But these can still cause damage to intervening tissues.
Researchers in Rice University Texas USA thought that by tuning nanoshells to strongly absorb light in the near infrared, where optical transmission through tissue is optimal, nanoshells embedded in tissues can be used to deliver a therapeutic dose of heat to the tissues by moderately low levels of light applied outside the body.
In a paper just published in the PNAS (house journal of the US National Academy of Sciences), the research team reported that human breast carcinoma cells in culture incubated with nanoshells died when exposed to near infrared light (820nm, 35W/cm2) while control cells not containing nanoshells appeared unharmed.
Similarly, in live animals with solid tumours into which metal nanoshells were injected, exposure to near infrared light (820nm, 4W/cm2) caused the tumours to heat up by some 400C, while controls without nanoshells heated up by less than 100C. Cells in tissues heated above the thermal-damage threshold were killed, while control tissues appeared undamaged.
The gold surface of the nanoshell can also catalyse the self-assembly of polyethylene glycol, antibodies, or a variety of other agents. This offers the potential to target the nanoshells to specific diseased tissues.
But are the nanoshells safe? They are non-biodegradable and have enhanced catalytic capabilities. What happens to the nanoshells in the dead cells when they are cleared by the immune system? What effects do they have on the health of the patient in the long term? What are the wider environmental impacts when these nanoshells are discharged or released? None of these questions have been addressed.
It is clear that enthusiasm to exploit the remarkable properties of metal nanoshells and other nanoparticles have run far ahead of any safety concerns. It is time for responsible scientists to impose a moratorium on research and development until proper safeguards are put in place.
Source
Hirch LR, Stafford RJ, Bankson JA, Sershen SR, Rivera B, Price RE, Hazle JD, Halas NJ and West JL. Nanoshell-mediated near-infrared thermal therapy of tumors under magnetic resonance guidance. PNAS 2003, 100, 13549-54.
This article was found on the I-SIS website http://www.i-sis.org.uk/
To give both sides of the discussion around nanotech, here is an exchange of messages with someone who is closely involved:From: zeus
To: Undisclosed-Recipient
Sent: Monday, April 28, 2003
Subject: NANOTECHNOLOGYThere was a great deal about this in yesterday's Mail on Sunday (27/4/03). The front page headline 'Charles: 'Grey Goo' Threat to the World' says 'Prince Charles was last night on a collision course with Tony Blair after warning of the doomsday risks of a controversial new science.'
'Following his successful campaign on GM foods, the Prince has now called together Britain's leading experts after highlighting the dangers of scientists' 'playing God'.'
'In a move putting him in direct conflict with the Prime Minister, who backs the cutting-edge science of nanotechnology, the Prince will host a crisis summit of experts at his Highgrove home and has contacted leading opinion formers.'
'He fears the worst case scenario of what scientists call the 'grey goo' theory in which nanotechnology spinoffs would annihilate life on Earth.'
Zeus Information Service
Political News
for Alternative Health Practitioners
to subscribe contact info@zeusinfoservice.com
From: "Paul"
Subject: RE: NANOTECHNOLOGY
Date: Mon, 15 Mar 2004
The Prince Charles thing is ancient and I believe he's been pretty quiet since and has probably given the person who alerted him to the issue a few sharp words. Just as he followed the line of the ETC Group they suddenly changed theirs.
Eco article 1:
Looked okay, factually, what I could get of it (I suspect the writer had read the white paper I wrote), but it looks like it gets truncated before it gets to anything opinion-like. An odd ending, otherwise.
Eco article 2:
The stuff about making new humans and such is something many, including myself, thought was ridiculous to include in a government document like the 'Convergence' one. All that sort of stuff is so speculative (e.g. downloading brains to computers, enhancing memory by re-engineering brain cells or plugging components into them) that it's pretty pointless to be arguing about it now. Like the science fiction of the thirties, some will come true, but the vast majority will just look silly many years on. Roco has a lot to answer for.
The drop down box on nanobot advances falsely suggests a great deal of progress. Work has hardly begun. They will happen one day, I believe, but will be no more scary than a factory robot. Ones that can copy themselves and spread are also theoretically possible (just as a virus is) but infinitely more difficult. Besides which, we've already got viruses - far more dangerous to start tinkering with them, as is happening already (as someone deeply involved in nanotech, it is this sort of genetic tinkering that keeps me awake at nights, and nanotech currently plays no part in it).
The points about whether the disadvantaged in the world will catch up or fall behind more as a result of a technology is applicable to all technologies and a question well worth asking. Nanotechnology is too diverse to apply it en bloc, it needs applying to all nanotechnologies in turn. Applying it to human enhancement is premature.
Eco article 3:
Reactionary and uninformed. The dangers of nanotech that aren't so speculative as to be science fiction are so far not looking like too much to worry about. However, a bit more worrying should have been done a bit earlier, but that's easy to say with hindsight. The myriad chemicals already being produced that have not been adequately tested should cause far more concern than nanoparticles.
The article makes the fundamental mistake of calling nanotechnology a single thing. It is a diverse collection of technologies. If someone tried to tell you that 'books' were bad, you would demand the clarification of which books.
The scenario about the way a new technology is introduced is palpably wrong for most technologies, although parts of it are probably true of quite a few technologies. The whole scenario points at definite areas for concern (e.g. signficant commercial investment before checking for adverse effects) but is far too glib to be generally useful. It annoys me when valuable points are misused like this - it diminishes their value for others.
Scientific ignorance: l'Oreal's nanosomes and nanoparticles are not even remotely the same thing. However, l'Oreal do also use nanoparticles in their products. As do many companies.
Drop Box: Moratorium on nanotech suggested. No one can even agree on a definition of nanotech. Even if you got people to do so then it would be an incredibly diverse set of technologies, many that could be considered with a high degree of confidence as risk-free, e.g. nanopattering catalytic surfaces or the use of thin films (nanoscale thickness) in the read/write heads of hard drives for the last decade. Now, suggest a moratorium on the release of nanoparticles and I'd say you're starting to approach something justifiable, although not workable, and probably an overreaction in the scale of things. Would you include carbon black that's been in car tyres for decades?
The article also fails to look at the opportunities that are presented by nanotech (and probably safe nanotechnologies too). These are many, my favourite being a breakthrough in solar energy, reducing costs by 5 to 20 times for the same efficiency. Five times would make it competitive with fossil fuels in large parts of the world. In India the competitive balance is hit sooner since they do not have much of a grid system. The consequences of these developments really excite me in terms of geopolitical balance and providing basic amenities and education to the poor. Will multinationals scupper those hopes? I doubt it, but I really wouldn't mind seeing people asking the question instead of suggesting a moratorium on nanotech. Hey, how about a moratorium on chemistry? Get real.
Oops, I made the decision some time ago not to wear away any more of my keyboard on such uninformed material unless it was to a particularly large audience. Basically, if you're going to try and criticise something or start telling everyone it's dangerous, please at least make some effort to understand what 'it' is first.
You guys know all about putting your energy in the right place. Thankfully, things seem to be moving towards sanity in nanotech.
Cheers to all,
Paul.
Update August 2004
From ETC Group - on the Royal Society Report on Nanotech
Thursday, 29 July 2004
www.etcgroup.org
UK Report: More Hits than Misses on Nanotech
After a year-long investigation, the United Kingdom's Royal Society and Royal Academy of Engineering released its final report today examining the health, safety, environmental, ethical and societal implications of nano-scale technologies. The report was commissioned by the UK government last June. The UK's Trade Union Congress today supported the Royal Society's report and called for strong regulations to prevent worker exposure to manufactured nanoparticles. "There have been plenty of red flags, but the dollar signs have blotted out the warnings signs," said Rory O'Neill, spokesman for the Trade Union Congress.
"The report is a good start toward addressing the potential negative health and environmental impacts of nano-scale technologies, particularly the use of nanoparticles," said Jim Thomas, European Programme Manager of the ETC Group based in Oxford. "Just one year ago Lord Sainsbury [UK Science Minister] said that nanotech was adequately covered by regulations - he was wrong. We welcome the Royal Society's precautionary language on the environment and strong recommendations on nanoparticles."
Today's report vindicates many of those, like ETC Group, who have expressed concerns about the dangers of nanotechnology for human health and the environment in the absence of regulatory oversight.
Importantly, the Royal Society considered many broader societal issues and seems to have listened carefully to the key questions raised by Prince Charles in his July 11 editorial on nanotechnology appearing in The Independent on Sunday - who controls nanotechnology and who will benefit from it?
"The report is undeniably impressive and constructive. It raises all the right questions, even though some of its answers are incomplete and uneven," notes Thomas. "While acknowledging the issues of ownership and control as fundamental, it fails to adequately address them. There is no discussion of nanotech monopolies or the implications of nanotech for the global South. And despite the UK's colossal controversy over agbiotech, the report fails to examine the impacts of nanotech on agriculture and food production."
The Royal Society's report also falls short in its assessment of the potential risks of nanobiotechnology. It naively puts the impacts of nanobiotech in the distant future (more than 10 years), and it starts with the premise that nanobiotech applications will not include the production and enhancement of biological material through genetic modification technologies. Considering genetic modification and nano-scale technologies as separate spheres of science allows the authors to dismiss self-replication as an irrelevant concern. "In reality, nanotech and biotech are already converging to create hybrid materials, machines and living organisms," asserts Thomas. "The report itself acknowledges hybrid bio-nano machines and recognizes converging technologies as a profound issue. The report's dismissal of the relevance of genetic modification to nanobiotechnology is contradictory."
Health, Safety & Environment: The Royal Society's report considered but rejected the need for a moratorium on nanotechnology, which the ETC Group called for two years ago, but it unambiguously concludes that uncertainties about the risks of manufactured nanoparticles "need to be addressed immediately" to safeguard workers and consumers. The Royal Society's decision to reject the call for a moratorium seems to be based more on politics than science in light of their bold recommendations:
* Ingredients in the form of nanoparticles should undergo full safety assessment (even if the substance has already been assessed in larger forms) before being commercialized. [De facto moratorium? What should be done about nanotech products already on the shelf?]
* The use of free manufactured nanoparticles (not fixed to or within a material) in environmental applications such as remediation should be prohibited until appropriate research has been undertaken.
* Chemicals in the forms of nanoparticles should be treated by regulators as new substances (thus acknowledging that properties of nanoscale particles may be different from the same chemical substance in larger forms).
* Factories and research laboratories should treat manufactured nanoparticles and nanotubes as if they are hazardous and seek to reduce or remove them from waste streams.* Industry should make public all relevant data related to safety assessments of manufactured nanoparticles, and demonstrate how they have taken into account that properties of nanoparticles may be different from larger forms.
* Consumer products containing manufactured nanoparticles should be labeled on ingredients lists.
* All relevant regulatory bodies in the UK should review whether existing regulations are appropriate to protect humans and the environment from potential nanotech hazards, and report on how regulatory gaps will be addressed.* With the support of the UK, the European Commission should review the adequacy of current regulations with respect to the introduction of nanoparticles into any consumer products.
Convergence: The report notes that the future convergence of nanotech with biotechnology, information and cognitive sciences could be used for "radical human enhancement" and that, if realized, would raise "profound ethical questions" regarding what we understand to be human, normal and abnormal. With input from Richard Light, Director of the Centre for Disability and Human Rights, and from Gregor Wolbring, Director of the Centre for Bioethics, Culture and Disability, the report points to the problematic nature of a "technical fix" to address "disability." Clearly, new technologies can't solve social injustices.
The Bigger Picture: The report recommends that the impacts of emerging technologies "be addressed with some urgency." Specifically, the Royal Society recommends the establishment of a multi-stakeholder group to look at new and emerging technologies and to identify and advise "at the earliest possible stage" where potential health, safety, environmental, social, ethical and regulatory issues may arise and how to address them. The group's work "should be made public so that all stakeholders can be encouraged to engage with the emerging issues." The report also recommends that the government initiate adequately funded public dialogue around the development of nanotechnologies."We are pleased to see that the Royal Society takes seriously the need to create a new body that has the mandate to assess the broader societal impacts of new technologies, similar to what we have called for at the intergovernmental level," said Pat Mooney, Executive Director of ETC Group. The ETC Group advocates for the establishment of a United Nations body, the International Convention on the Evaluation of New Technologies.
For further information:
Jim Thomas, ETC Group (UK) jim@etcgroup.org
Pat Mooney, ETC Group (Canada) etc@etcgroup.org
Silvia Ribeiro, ETC Group (Mexico) silvia@etcgroup.org
Hope Shand and Kathy Jo Wetter, ETC Group (USA)
kjo@etcgroup.org, hope@etcgroup.orgThe Royal Society's report, "Nanoscience and nanotechnologies: opportunities and uncertainties," is available on the Internet: http://www.nanotec.org.uk/finalReport.htm
The Trade Union Congress report, "Nanotechnology - the new asbestos," is available on the Internet: http://www.hazards.org/nanotech
For a basic introduction to nano-scale technologies and an analysis of their implications, see The Big Down, From Genomes to Atoms: Technologies Converging at the Nano-scale
http://www.etcgroup.org/upload/publication/171/01/thebigdown.pdf
For a critique of the strategy of converging technologies and an analysis of its implications,
see "The Little BANG Theory" http://www.etcgroup.org/en/node/55For an introduction to the issues surrounding the toxicity of engineered nanoparticles, see "No Small Matter!" and ETC Group's Occasional Paper "Size Matters!" for a more detailed analysis and a list of products containing nanoparticles.
http://www.etcgroup.org/upload/publication/165/01/occ.paper_nanosafety.pdf
For a short list of the most worrying scientific findings involving nano-scale technologies, see "Nano's Troubled Waters"
http://www.etcgroup.org/upload/publication/116/01/gt_troubledwater_april1.pdf
For a brief analysis of nanotech governance, see "26 Governments Tiptoe Toward Global Nano Governance" http://www.etcgroup.org/upload/publication/pdf_file/globalgovfinal.pdf
See also:
Do Nanoparticles in Food Pose a Health Risk?
Friends of the Earth (FoE) reports that none of the more than 100 food or food-related products it identified that contain nanoparticles—puny particles between 100 and one nanometers—bears a warning label or has undergone safety testing by government agencies."Products created using nanotechnology have entered the food chain," says report author Ian Illuminato, FoE's health and environment lobbyist. "Preliminary studies indicate there is a serious risk…. We should know that it's safe before we put it in our food."
Wired Magazine: The Incredible Shrinking Man
K. Eric Drexler was the godfather of nanotechnology. But the MIT prodigy who dreamed up molecular machines was shoved aside by big science - and now he's an industry outcast.
Probing the promise and perils of nanoparticles
New research raises questions about buckyballs and the environment
May 09, 2005 - In a challenge to conventional wisdom, scientists have found that buckyballs dissolve in water and could have a negative impact on soil bacteria. The findings raise new questions about how the nanoparticles might behave in the environment and how they should be regulated, according to a report scheduled to appear in the June 1 print issue of the American Chemical Society's peer-reviewed journal Environmental Science & Technology. ACS is the world's largest scientific society.
August 19, 2005: Nano coalition unveils environmental, health and safety database
October 2005: Combined Forces Of Physics And Medicine To Investigate Hidden Toxity
A physicist and a medical researcher at the University of Leicester have received a grant of £100,000 from the Engineering and Physical Sciences Research Council to look at possible toxic damage from inhaled nanoparticles used for a range of everyday purposes.
Nanotechnology: Big trouble in the mini-revolution?
Nanotechnology could treat cancer or create clean energy. But what happens if nano-particles enter our bodies? Jimmy Lee Shreeve reports on the mounting fears
Health fears as hi-tech science hits the shops
May 2006 - EBEN HARRELL AND IAN JOHNSTON
"The technology and applications of nanoparticles are racing ahead and still we haven't actually put together a proper research programme into the effect of nanoparticles on the biological system." - Professor Anthony Seaton
Nano coalition unveils environmental, health and safety database
This environmental health and safety (EHS) database marks the first effort to integrate the vast and diverse scientific literature on the impacts of nanoparticles, which are tiny pieces of matter with dimensions measuring between 1 and 100 nanometers and containing between tens and thousands of atoms.
Understanding Potential Toxic Effects of Carbon-Based Nanomaterials
Various types of carbon-based nanomaterials, such as buckyballs and nanotubes, have shown promise as drug delivery tools and imaging agents, but reports of toxicity associated with some of these materials have raised questions about their ultimate utility in clinical oncology. Three recent reports in the literature provide new insights into why certain carbon-based nanomaterials are toxic to cells and others are not.
FDA Gets Mixed Advice on Nanotechnology
"We cannot assume what we know about bulk-size substances applies to the nanotechnology-size substances," Philippe Martin, of the European Commission, told the meeting. Martin cited the ring he wears: it's made of gold, is yellowish and inert. But take a gold nanoparticle one nanometer in size, and it turns both blue and mildly reactive. Bump the size up to three nanometers, and the gold turns a reddish hue and now acts like a catalyst.Kathy Jo Wetter, of the civil society organization ETC Group, told the FDA it was understaffed, underfunded and ill-equipped to deal with nanotechnology. Wetter said hundreds of nano products have already crept onto the market with little scrutiny. "Unfortunately, so far the U.S. government has acted as a cheerleader and not as a regulator," Wetter said.
Berkeley to Regulate Nanotechnology
The City Council is expected Tuesday to amend its hazardous materials law to compel researchers and manufacturers to report what nanotechnology materials they are working with and how they are handling the tiny particles."This actually is a groundbreaking ordinance," Berkeley Mayor Tom Bates said during the city's Dec. 5 meeting, when the issue received unanimous support during its preliminary introduction to the City Council. "The EPA and the federal government have basically not looked at nano particles."
Researchers probe health and safety impacts of nanotechnology
Powers said the health and environmental effects of common metals and materials are well-known. The question for the researchers is whether the effects change when the metals and materials take the form of nanoparticles – and whether these nanoparticles become more or less hazardous based on shape and size. "It's complicated," he said. "In many cases, we lack basic knowledge of the properties and the behavior of the particles themselves."
Widely used iron nanoparticles exhibit toxic effects on neuronal cells
Researchers at UC San Diego have discovered that iron-containing nanoparticles being tested for use in several biomedical applications can be toxic to nerve cells and interfere with the formation of their signal-transmitting extensions."Iron is an essential nutrient for mammals and most life forms and iron oxide nanoparticles were generally assumed to be safe," said Sungho Jin, a professor of materials science at UCSD and senior author of a paper to be published in Biomaterials. The paper is currently available on the journal's website. "However, there are recent reports that this type of nanoparticle can be toxic in some cell types, and our discovery of their nano-toxicity in yet another type of cell suggests that these particles may not be as safe as we had once thought."
Amid Nanotech's Dazzling Promise, Health Risks Grow
Halfway through, Trouiller became alarmed: Consuming the nano-titanium dioxide was damaging or destroying the animals' DNA and chromosomes. The biological havoc continued as she repeated the studies again and again.Nano-titanium dioxide is so pervasive that the Environmental Working Group says it has calculated that close to 10,000 over-the-counter products use it in one form or another. Other public health specialists put the number even higher. It's "in everything from medicine capsules and nutritional supplements, to food icing and additives, to skin creams, oils and toothpaste," Schiestl says. He adds that at least 2 million pounds of nanosized titanium dioxide are produced and used in the U.S. each year.
posted by Sepp Hasslberger on Saturday November 29 2003
updated on Friday December 10 2010URL of this article:
http://www.newmediaexplorer.org/sepp/2003/11/29/nanotubes_nanoshells_what_are_the_consequences.htm
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