Welcome to the MINChar Initiative

by Andrew Maynard on November 8, 2009

The Minimum Information on Nanoparticle Characterization (MINChar) initiative aims to raise the quality of research surrounding the potential toxicity of nanomaterials, by supporting appropriate materials characterization.  Growing out of a workshop held in Washington DC in October 2008, it provides a forum for researchers and others involved in assessing the hazards of engineered nanomaterials to exchange information and share ideas on ensuring materials are characterized in a way that allows informed interpretation of data, and cross-comparison of results.

The key material characterization recommendations arising from the 2008 workshop can be found here.

Further information on MINChar can be found here.

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A Letter to the Editor published in the Journal of Food Science recently proposed a set of nine characterization parameters for studies on food and food-related nanomaterials.  The letter, from Jeffrey Card (Ashuren Health Sciences) and Bernadene Magnuson (Cantox Health Sciences International), cites the MinChar list as one of a number of sources.

From the letter:

We propose that a set of minimum parameters be determined and reported for nanomaterials that are used in experiments assessing various biological activities, including toxicity, regardless of the route of exposure that is being examined. This set includes the following 9 parameters:

  • agglomeration and/or aggregation
  • chemical composition
  • crystal structure/crystallinity
  • particle size/size distribution
  • purity
  • shape
  • surface area
  • surface charge
  • surface chemistry (including composition and reactivity)

The letter can be accessed at JFS Vol 74, Number 8.

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A recent editorial in the journal Nanotoxicology which addresses the dangers of indiscriminate generalizations on nanoparticle toxicity, has just been made freely available for a limited time.

In Nanoparticles – one word: A multiplicity of different hazards (Nanotoxicology Vol. 3, No. 4, Pages 263-264), 12 authors express their concern over “how the term “nanoparticles” is being somewhat indiscriminately used, especially in the titles of scientific papers and in statements to the press.”  They state:

No self-respecting researcher would dream of publishing results showing, for example, that quartz was a genotoxin under the title ‘Particles are genotoxic’. Generalizations like these are unhelpful and unscientific, and potentially dangerous in the wrong hands. Exactly the same applies for research into the toxicology and potential impacts of nanoparticles. Yet in 2009, papers are still appearing that explore the activity of a small range of nanoparticle types, yet uses the term ‘nanoparticle’ in its broadest sense in the title as though it was a generically useful term representing one class of hazard.

Responding in part to a recent paper that linked nanoparticles in the most general sense to seven very serious cases of occupational lung and pleural injury occurring in China (Song et al. 2009), the authors urge the author of papers to:

  1. Ensure that all descriptions of nanoparticle hazards recognize the intrinsic heterogeneity of the nanoparticle hazard and discuss the uncertainty of alleged causality;
  2. Ensure that there is a convincing and scientifically sustainable link between any nanoparticle exposure and any pathological outcomes putatively associated with that exposure; and
  3. Ensure that sufficient physical and chemical characterization data are provided on the nanoparticles in question to support valid data interpretation and comparison.

The full paper van be accessed at http://dx.doi.org/10.3109/17435390903337701

The paper’s authors are (in alphabetical order):

Dr Rob Aitken, SAFENANO, Institute of Occupational Medicine, Edinburgh, UK

Professor Paul Borm, Hogeschool Zuyd, Heerlen, The Netherlands

Professor Ken Donaldson, University of Edinburgh, Edinburgh, UK

Professor Gaku Ichihara, Nagoya University, Nagoya, Japan

Professor Steffen Loft, University of Copenhagen, Copenhagen, Denmark

Professor Francelyne Marano, Université Paris Diderot-Paris 7, Paris, France

Dr Andrew Maynard, Woodrow Wilson Centre, Washington DC, USA

Professor Günter Oberdörster, University of Rochester, Rochester, NY, USA

Dr Herman Stamm, European Commission Joint Research Centre, Ispra, Italy

Professor Vicki Stone, Edinburgh Napier University, Edinburgh, UK

Dr Lang Tran, Institute of Occupational Medicine, Edinburgh, UK

Professor Hakan Wallin, National Research Centre for the Working Environment, Copenhagen, Denmark

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On Tuesday November 17th, Travis Earles from the US Office of Science and Technology Policy (OSTP) emphasized strongly the Whitehouse’s support for developing and implementing good materials characterization practices in nanotoxicology studies.  Travis was speaking at the National Nanotechnology Initiative Human Health and Instrumentation Workshop.

The video of his presentation is available here, although you will need to register with the site to watch it (and currently it doesn’t seem to be viewable on a Mac).

I will try and post a transcript of the relevant sections of his presentation when it becomes available.

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Back in September, Darrell Boverhof and Ray David published a review article in Analytical and Bioanalytical Chemistry on nanomaterial characterization that draws on recommendations made on characterizationmatters.org.  The review is freely available online.

Nanomaterial characterization: considerations and needs for hazard assessment and safety evaluation

Darrell R. Boverhof (1) and Raymond M. David (2)

(1) Toxicology & Environmental Research and Consulting, The Dow Chemical Company, Midland, MI 48674, USA

(2) BASF Corporation, 100 Campus Dr, Florham Park, NJ 07932, USA

Received: 10 July 2009 Revised: 21 August 2009 Accepted: 23 August 2009 Published online: 15 September 2009


Nanotechnology is a rapidly emerging field of great interest and promise. As new materials are developed and commercialized, hazard information also needs to be generated to reassure regulators, workers, and consumers that these materials can be used safely. The biological properties of nanomaterials are closely tied to the physical characteristics, including size, shape, dissolution rate, agglomeration state, and surface chemistry, to name a few. Furthermore, these properties can be altered by the medium used to suspend or disperse these water-insoluble particles. However, the current toxicology literature lacks much of the characterization information that allows toxicologists and regulators to develop “rules of thumb” that could be used to assess potential hazards. To effectively develop these rules, toxicologists need to know the characteristics of the particle that interacts with the biological system. This void leaves the scientific community with no options other than to evaluate all materials for all potential hazards. Lack of characterization could also lead to different laboratories reporting discordant results on seemingly the same test material because of subtle differences in the particle or differences in the dispersion medium used that resulted in altered properties and toxicity of the particle. For these reasons, good characterization using a minimal characterization data set should accompany and be required of all scientific publications on nanomaterials.

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Welcome to the new-look Characterization Matters site

by Andrew Maynard on November 8, 2009

Characterization matters is undergoing a bit of a reorganization.  Along with a new (and hopefully more attractive and intuitive) layout, I’m taking the opportunity to reorganize the site and rethink how best to engage the community in using it and contributing to it.

Please keep an eye out for future updates, and feel fee to let me know how you would like to see the site improved.



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Update: Contribiting to the discussion

by Andrew Maynard on March 19, 2009

A few things have come up recently regarding the MINChar website that I thought were worth mentioning:

  • Some people would like to be listed as part of the MINChar Interest Group, but would rather not post a comment to that effect.  This is fine – if you fall into this category, please send me an email at andrew.maynard@2020science.org, and I’ll add you to the list.
  • It’s also been mentioned that email updates on additions to the website would be helpful.  I’m working on this – stay tuned.
  • Finally, I would love to see others post blogs on ideas, information, concerns that they feel would be interesting or useful regarding nanomaterial characterization.  If you would like to be a contributor, simply drop me an email and I will sign you up with an account.



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Something that it would be good to see this website used for is an exchange between instrument manufacturers and users – both to help people realize what is available (together with the abilities and limitations of devices), and to help manufacturers get a better handle on what researchers etc. are looking for.

Bob Carr from NanoSight has just posted a comment on their product for sizing nanoparticles in liquid suspensions – it would be great if other manufacturers felt free to share information, and users to share experiences.

I would add that Bob was reticent to post anything for fear of it sounding too much like a commercial – and only did so after asking whether I thought it was appropriate. Speaking to several people, it seemed that the information that could be gained from an informal dialogue with instrument manufacturers would most likely far outweigh any fears of inappropriate advertising. That said, it seems that some guidelines might be helpful for such a dialogue. These are my suggestions for guidelines – they are in no way binding, and are open to being modified, but hopefully will underpin useful exchange of information:

  1. Instrument manufacturers should feel free to post information on products and techniques that are relevant to nanomaterial characterization in toxicology studies, as long as the information is accurate, applicable, and useful to readers. Blatant advertising should be avoided.
  2. Manufacturers posting information should be prepared to field questions about their products and how to use them to obtain good data.
  3. Instrument users (and potential users) should be free to question manufacturers on their instruments and their use. However, unfounded and unhelpful criticism of instruments/manufacturers/suppliers is strongly discouraged.

If there’s enough interest in exchanging information here, I’ll look at setting up a separate page on this website for the dialogue.



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Chemical & Engineering News article on MINChar

December 15, 2008

This week’s issue of C&E News has a great article on the MINChar initiative by Britt Erickson. You can access the article here (Note: the article is from Volume 86, Number 50, pp. 25-26 (Dec 15 2008).  C&E News is a publication of the American Chemical Society.  This link is provided with the permission of […]

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Criteria for selecting minimum characterization parameters

December 11, 2008

At the October 28-29 workshop, a number of criteria and recommendations formed the basis of discussions on a minimum set of characterization parameters for nanotoxicology studies. This presentation (PDF, 284 KB) put together by Nigel Walker (National Institute of Environmental Health Sciences), Richard Pleus (Intertox Inc) and Richard Canady (FDA) provided a starting point for […]

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