Nanosicherheitsforschung – sind wir auf dem richtigen Weg?

Ein sehr kluger Bericht zur Nanosicherheit  12502_ftp

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Nanosafety Research

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Nanosafety research: The quest for the gold standard

Date:
October 29, 2014
Source:
Swiss Federal Laboratories for Materials Science and Technology (EMPA)
Summary:
Toxicologists have evaluated several thousand studies on the risks associated with nanoparticles and discovered no end of shortcomings: poorly prepared experiments and results that don’t carry any clout. Scientists are now developing new standards for such experiments within an international network.

Iron oxide nanoparticles on the surface of a cell.
Credit: EMPA

Empa toxicologist Harald Krug has lambasted his colleagues in the journal Angewandte Chemie. He evaluated several thousand studies on the risks associated with nanoparticles and discovered no end of shortcomings: poorly prepared experiments and results that don’t carry any clout. Instead of merely leveling criticism, however, Empa is also developing new standards for such experiments within an international network.

Researching the safety of nanoparticles is all the rage. Thousands of scientists worldwide are conducting research on the topic, examining the question of whether titanium dioxide nanoparticles from sun creams can get through the skin and into the body, whether carbon nanotubes from electronic products are as hazardous for the lungs as asbestos used to be or whether nanoparticles in food can get into the blood via the intestinal flora, for instance. Public interest is great, research funds are flowing — and the number of scientific projects is skyrocketing: between 1980 and 2010, a total of 5,000 projects were published, followed by another 5,000 in just the last three years. However, the amount of new knowledge has only increased marginally. After all, according to Krug the majority of the projects are poorly executed and all but useless for risk assessments.

How do nanoparticles get into the body?

Artificial nanoparticles measuring between one and 100 nanometers in size can theoretically enter the body in three ways: through the skin, via the lungs and via the digestive tract. Almost every study concludes that healthy, undamaged skin is an effective protective barrier against nanoparticles. When it comes to the route through the stomach and gut, however, the research community is at odds. But upon closer inspection the value of many alarmist reports is dubious — such as when nanoparticles made of soluble substances like zinc oxide or silver are being studied. Although the particles disintegrate and the ions drifting into the body are cytotoxic, this effect has nothing to do with the topic of nanoparticles but is merely linked to the toxicity of the (dissolved) substance and the ingested dose.

Laboratory animals die in vain — drastic overdoses and other errors

Krug also discovered that some researchers maltreat their laboratory animals with absurdly high amounts of nanoparticles. Chinese scientists, for instance, fed mice five grams of titanium oxide per kilogram of body weight, without detecting any effects. By way of comparison: half the amount of kitchen salt would already have killed the animals. A sloppy job is also being made of things in the study of lung exposure to nanoparticles: inhalation experiments are expensive and complex because a defined number of particles has to be swirled around in the air. Although it is easier to place the particles directly in the animal’s windpipe (“instillation”), some researchers overdo it to such an extent that the animals suffocate on the sheer mass of nanoparticles.

While others might well make do without animal testing and conduct in vitro experiments on cells, here, too, cell cultures are covered by layers of nanoparticles that are 500 nanometers thick, causing them to die from a lack of nutrients and oxygen alone — not from a real nano-effect. And even the most meticulous experiment is worthless if the particles used have not been characterized rigorously beforehand. Some researchers simply skip this preparatory work and use the particles “straight out of the box.” Such experiments are irreproducible, warns Krug.

The solution: inter-laboratory tests with standard materials

Empa is thus collaborating with research groups like EPFL’s Powder Technology Laboratory, with industrial partners and with Switzerland’s Federal Office of Public Health (FOPH) to find a solution to the problem: on 9 October the “NanoScreen” programme, one of the “CCMX Materials Challenges,” got underway, which is expected to yield a set of pre-validated methods for lab experiments over the next few years. It involves using test materials that have a closely defined particle size distribution, possess well-documented biological and chemical properties and can be altered in certain parameters — such as surface charge. “Thanks to these methods and test substances, international labs will be able to compare, verify and, if need be, improve their experiments,” explains Peter Wick, Head of Empa’s laboratory for Materials-Biology Interactions.

Instead of the all-too-familiar “fumbling around in the dark,” this would provide an opportunity for internationally coordinated research strategies to not only clarify the potential risks of new nanoparticles in retrospect but even be able to predict them. The Swiss scientists therefore coordinate their research activities with the National Institute of Standards and Technology (NIST) in the US, the European Commission’s Joint Research Center (JRC) and the Korean Institute of Standards and Science (KRISS).


Story Source:

The above story is based on materials provided by Swiss Federal Laboratories for Materials Science and Technology (EMPA). Note: Materials may be edited for content and length.


Journal Reference:

  1. Harald F. Krug. Nanosicherheitsforschung – sind wir auf dem richtigen Weg? Angewandte Chemie, 2014; DOI: 10.1002/ange.201403367

Cite This Page:

Swiss Federal Laboratories for Materials Science and Technology (EMPA). “Nanosafety research: The quest for the gold standard.” ScienceDaily. ScienceDaily, 29 October 2014. <www.sciencedaily.com/releases/2014/10/141029124553.htm>.
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A short course on image analysis for particle description

Initiated by a discussion about 2-D or eventually better 3-D image analysis for particle description I decided to post a copy of a course I gave on that theme to show the complexity of this question. Please have a look at the detailed presentation.

 

 

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Precision and resolution achievable using Sympatec’s NANOPHOX

By its cross correlation method (PCCS) NANOPHOX is able to eliminate scattering information that is not due to Brownian motion as e.g. multiple scatter, cuvette surface inhomogeneity  etc.. This results in the best possible raw data for evaluation.
In NANOPHOX the user has the choice between 2nd Cumulant, auto-NNLS
(an operator independent evaluation mode for validation tasks) and the expert-NNLS mode (with guided manual fit range seting).

Please read the details in this PDF

 

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Necessary sample size for counting

This is a translated excert of a chapter from famous Prof. Leschonski’s “Clausthaler Kurs”  describing the necessity of large numbers of particles to count for accurate sizing.

Random eror PDF

 

 

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NANO-Technology Chance and/or Risk

The fear of new unknown technologies is as old as progress itself and often leads to irrational suggestions for coping with it as shown in this image of protection against railway accidents from 1847. read more about it in detail: Reasonal risk evaluation needs deeper insight.

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An impressive and coherent course about risk evaluation. (Also applicable to nano particle risk evaluation!)

Just recently Toni Harrison on LinkedIn pointed to a very helpfull video regarding risk evaluation done by Peter Sandman.
This explains in a coherent way why nano danger pubications gain so much publicity, but also how they gain influence and what they mean whith respect to real danger.
http://www.youtube.com/watch?v=WU__jJzr_Hw
This clip is a brief excerpt (9:37) from a two-day seminar I gave in 2010 for the Rio Tinto mining company.  The excerpt explains my signature formula, “Risk = Hazard + Outrage” — which aims to capture the crucial truth that people focus more on how upsetting a risk is than on how dangerous it is.
A much longer clip explaining the ramifications of this formula is available on Vimeo at http://vimeo.com/18611416.  I’m posting this excerpt on YouTube almost as an advertisement.  I’d really rather people watched the longer version.
Links to all my clips from this Rio Tinto training (as well as other audio and video resources) can be found on my website at http://www.psandman.com/media.htm.  The Rio Tinto clips add up to a free online course on my approach to risk communication and especially to low-hazard high-outrage risk communication, which I call “outrage management.”     –Peter Sandman

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Deutscher Verband Nanotechnologie opens additional regional office in Hamburg

CAN opens regional branch office of Deutscher Verband Nanotechnologie e.V.

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Important NANO links

This is a list of the actually links regarding NANO in the web,
state of oct. 2011 .
Open the list view

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Measuring means comparing!

An attempt to screen the actual available particle sizing methods and instruments.

please click here to view the record

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Detailed scientific insight into nano concerned forces

The most complete compendium for nano behavior I could find is:

Intermolecular and surface forces”  by Jacob N. Israelachvili 
issued by Academic Press

 

This forms a reasonable scientific basis for all discussions on nano particles, their properties, interactions and enables deep insight into fundaments.

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Diskussion on Nano particles counting on LinkedIn

Just for some days there is an interesting discussion going on to: Nano particle counting

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Size- & Zeta-potential-measurement, you only get what you pay for!

You only get what you pay for! Are low budget instruments worth what you pay for it?

“Nano” is one of the most attractive and modern terms in research, industry and marketing.
Due to the excellent definition work of the ISO committee TC229 since August 2008 there is a precise determination what “Nano” really means (ISO/TS27687). Also development in this field, as well as increasing knowledge is growing daily at an accelerating speed. Continue reading

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Sample preparation of nano material for size determination

According to the valid definitions in ISO/TS 27687: August 2008 and the standardl particle definitions in accordance with ISO TC 24/SC 4, TC 146 and TC 209 there is a clear definition of nano particles respectively nano objects. Only for these nano objects, where one, two or three external dimensions are in the nanometer range below 100nm, the term nano particles should be used.
All coarser particles are submicron particles and should not be called nano particles anymore. The same is valid for so called nano structured material, which is aggregated from nano objects. Continue reading

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The use of Zeta-potential in Nano analytics

In relation with production and stabilization of Nano-objects there is very often the talk about observing/ setting the right Zeta-potential. Also a lot of actual analytical instruments promote Zeta-potential determination together with e.g. size determination.

Continue reading

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Particle-Size-Measuring in the NANOmeter-range

NANO is an in many cases even in technical literature incorrectly used term. The Technical Committee 229 of ISO is deserving thanks for an exact definition with respect to particle size measurement in August 2008. (ISO/TS27687).
According to this definition only NANO-objects should be called NANO-particles if its three coordinate dimensions are all within the NANO-range of about 1 nm to 100 nm.
Regrettably even today many scientific publications still use the NANO-term in very imprecise manners. One reason for this might be the difficulty to measure NANO-Particles sufficiently precise. Imprecise knowledge of dimensions often leads to inaccurate classification. Continue reading

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