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

Abstract

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.

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.

Cheers,

Andrew

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.

]]> http://characterizationmatters.org/2009/11/08/welcome-to-the-minchar-initiative/feed/ 0 http://characterizationmatters.org/2009/03/19/update-contribiting-to-the-discussion/ http://characterizationmatters.org/2009/03/19/update-contribiting-to-the-discussion/#comments Thu, 19 Mar 2009 14:45:49 +0000 Andrew Maynard http://characterizationmatters.org/?p=261

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.

Cheers,

Andrew

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 discussions.

Comparison of possible parameters from ISO, OECD, NIST, Warheit and Ray. Excepted from the presentation.

]]> http://characterizationmatters.org/2008/12/11/criteria-for-selecting-minimum-characterization-parameters/feed/ 0 http://characterizationmatters.org/2008/12/02/workshop-attendees-at-the-oct-28-29-workshop/ http://characterizationmatters.org/2008/12/02/workshop-attendees-at-the-oct-28-29-workshop/#comments Tue, 02 Dec 2008 16:14:42 +0000 Andrew Maynard http://characterizationmatters.wordpress.com/?p=188

Attendees at the Oct 28-29 workshop, held in Washington DC, included:

Andrew Atkinson, Environment Canada
Barbara Beck, Gradient Corporation
Darrell Boverhof,Dow
Rick Canady, FDA
Shaun Clancy, ISO
Vicki Colvin, Rice University
Ray David, BASF
Britt Erickson, ACS
Gregory Fritz, EPA
Bill Gulledge, ACC
Mark Hoover, NIOSH
Fred Klaessig, Pennsylvania Bio Nano Systems, LLC
Steve Klaine, Clemson University
Kristen Kulinowski, Rice University
Daniel Chuantung Lin, EPA
Igor Linkov, US Army
Laurie Locascio, NIST
Chris Long, Gradient Corporation
Martha Marrapese, Keller and Heckman
Andrew Maynard, Project on Emerging Nanotechnologies
Jeff Morris, EPA/ORD
Vladimir Murashov, NIOSH
Anil Patri, NIH
Rick Pleus, ISO
Mike Postek, NIST
Ashutosh Riswadkar, Zurich North America
Aaron Roberts, University of North Texas
Steve Roberts, University of Florida
Nora Savage, EPA
Ralph Sturgeon, National Research Center
Canada Geoff Sunahara, National Research Center Canada
Clayton Teague, National Nanotechnology Coordination Office
Sally Tinkle, National Institute of Environmental Health Sciences (NIEHS)
Nigel Walker, National Institute of Environmental Health Sciences (NIEHS)
Angela R. Hight Walker, NIST
Karen Weinch, BASF
Mark Weisner, Duke University
Jim Willis, EPA

Welcome to the Minimum Information for Nanomaterial Characterization Initiative.

This is a community initiative to improve the level of materials characterization in nanotoxicology studies.  It aims to complement other activities by encouraging the adoption of a minimum set of physical and chemical material characterization parameters in nanotoxicology studies.

Development of an organized approach to documenting critical characterization parameters is also seen as being of benefit to related activities such as nano-manufacturing and materials science.

The recommended parameters, developed at a workshop held in Washington DC between Oct 28-29 2008, can be found here.

These are designed to complement recommendations from other groups that include ISO and OECD.  And as they are a minimum set of parameters, it is anticipated that they will at some point be superseded.

But in the meantime, it is hoped that their widespread adoption and use within the nanotoxicology community will encourage a culture of more robust physical and chemical nanomaterial characterization, that enables better research interpretation and comparison.

As this is a community initiative, it stands or falls by the buy-in it receives from within the nanotechnology community.  You can become associated with the initiative by signing up on the Join The Community page.

Thank you.

Lead organizers:

Darrell Boverhof, The Dow Chemical Company
Shaun Clancy, Evonik Industries
Vicki Colvin, ICON
Ray David, BASF Corporation
Mark Hoover, NIOSH
Steve Klaine, Clemson University
Andrew Maynard, Woodrow Wilson International Center for Scholars
Nigel Walker, National Institute of Environmental Health Sciences (NIEHS)
David Warheit, DuPont

Workshop Summary

A workshop was held at the Woodrow Wilson Center in Washington DC between Oct 28 – 29 2008, with two aims:

• To develop minimal material characterization recommendations for nano-toxicology studies; and
• To develop a plan of action for encouraging adoption of these recommendations by researchers, research managers and research publishers.

This is a draft summary of workshop findings:

Purpose

• To develop minimal material characterization recommendations for nano-toxicology studies; and
• To develop a plan of action for encouraging adoption of these recommendations by researchers, research managers and research publishers.

Intended Outcomes

• Raise the bar for nanomaterial toxicology research, including
  • Facilitating/encouraging appropriate materials characterization in nano-toxicity studies
  • Fostering a culture of good nanomaterial characterization
• Enable effective use of research/increase relevance and impact of research
• Complement the work of other organizations, esp. ISO and OECD
• Encourage study designs that enable dose-response to be evaluated against alternative metrics
• Foster interdisciplinary collaborations

Anticipated Product

General guidance on nanomaterial characterization for the nanotoxicology research community (A tool that can be used by people funding, conducting, evaluating and using research)

Target Audiences

• Research Sponsors (Establishing guidelines for material characterization)
• Researchers (Generating data)
• Research evaluators (Providing a level of quality control on the dissemination of data through their existing professional and institutional responsibilities—and indirectly having an impact on study design)
• Research users (Decision-makers evaluating quality of data)

Recommended Minimum Physical and Chemical Characterization Parameters
What does the material look like?

• Particle size/size distribution
• Agglomeration state/Aggregation
• Shape

What is the material made of?

• Overall composition (including chemical composition and crystal structure)
• Surface Composition
• Purity (including levels of impurities)

What factors affect how a material interacts with its surroundings?

• Surface Area
• Surface Chemistry, including reactivity, hydrophobicity
• Surface Charge

Overarching considerations

• Stability—how do material properties change with time (dynamic stability), storage, handling, preparation, delivery etc?  Include solubility, and the rate of material release through dissolution.
• Context/Media—how do material properties change in different media; i.e. from the bulk material to dispersions to material in various biological matrices? (“as administered” characterization is considered to be particularly important)
• Where possible, materials should be characterized sufficiently to interpret the response to the amount of material against a range of potentially relevant dose metrics, including mass, surface-area and number concentration.

Notes

This framework is designed to stimulate appropriate characterization, while complimenting more specific guidance from organizations such as ISO and OECD.

Highlighting a key set of parameters without specifying prescriptive approaches to characterizing them is intentional, as an approach to fostering a culture of effective characterization without stifling innovation, developing a set of recommendations that are more likely to be considered by relevant communities, and allowing these recommendations to support the adoption of more authoritative guidelines from other sources. Furthermore, the intentional omission of defined methods is meant to foster discussions between researchers in the biological sciences and the materials sciences, both of whom play a role in characterizing the effects of nanomaterials on biological systems.

It was a shared view that inter-laboratory comparison studies, known to be desirable, are infrequent due to issues surrounding funding and accepted laboratory protocols.

Reference should be made to internationally recognized terms and definitions (e.g. ISO TC229), and to federally-funded institutions capable of providing characterization services.

Next Steps

• Consider establishing an independent web-based resource outlining the motivation, conclusions and recommendations of the workshop
• Develop a system to enable practitioners/stakeholders to sign up in support of the recommendations
• Publish a high profile article on the recommendations, and a path toward more appropriate nanomaterial characterization in toxicology studies