OECD Issues Final Report on Nanotechnology Meeting

The International Workshop on Documentary Standards for Measurement and Characterisation in Nanotechnologies was held February 26-28, 2008 at the National Institute of Standards and Technology, Gaithersburg (USA), in co-ordination with ISO, IEC, NIST and the OECD. The participants discussed the development, efficacy, harmonisation and uptake of documentary standards broadly relevant to the field of measurement and characterisation for nanotechnologies.

The final report of this meeting can be downloaded here

Summary of main conclusions and recommendations

1.1 In order to enhance the development, efficacy, harmonization and uptake of documentary standards broadly relevant to the field of measurement and characterization for nanotechnologies, there is a pressing need for:

• Greater communication and coordination within and between the various standards development organizations and with interested metrology institutes;
• The development of a centralized, maintained, searchable and freely accessible repository of information on existing standards and standardization projects in the field;
• The development and introduction of a freely accessible and searchable terminology and definitions database;
• Wider participation of stakeholders in identifying and verifying standards needs;
• Consideration of all available standardization instruments from Workshop Agreements through to full consensus standards and their equivalents in order to provide stakeholders with relevant documents in a timely manner;
• Urgent and detailed consideration of the instruments needed to address current concerns and challenges in investigating the implications for human health and environmental safety of manufactured nanomaterials.

1.2 Whilst recognizing the need for the development of standards-related techniques and protocols for characterization at the nanoscale, a clear need was also identified for good practice/guidance documents covering the suitability and limitations of measurement and characterization techniques for use with nanomaterials.

Such good practice/guidance documents should, inter alia, cover the following topics:

• Information needed when handling/using nanoparticles;
• Suites of measurement techniques that go together and the information the combined data set might provide (what measurement techniques are applicable and what are their limitations);
• Sample preparation for measurement, including consideration of dispersion and aggregation/agglomeration;
• Sample preparation for human and eco-toxicology testing;
• Stability considerations relevant to manufactured nanomaterials;
• Application and limitation of surface analysis to nanoparticles;
• The meaning of concentration in the context of nanoparticle dispersions, and how it should be expressed;
• Dose measurement and dosimetry for in vitro and in vivo human and eco-toxicology studies.

1.3 In the specific area of human health and toxicology, there is a need for greater dissemination, verification and validation of handling and testing protocols and related procedures by the broader community. In particular, there is a pressing need to 1 of 40 develop protocols for: pharmacokinetics – ADME (absorption, distribution, metabolism, excretion) and toxicology screening tests; particle characterization protocols that take into account the presence of biological coatings; methods to determine the stability of nanomaterials in biological matrices; and guidance documents for the preparation of suspensions of nanomaterials in various media, particularly biologically relevant fluids.

1.4 In the area of nanomaterials characterization, there is a need for clarity in the identification of measurands related to several materials properties, including those corresponding to endpoints addressed by the OECD Working Party on Manufactured Nanomaterials’ (WPMN) Sponsorship Programme for the Testing of Manufactured Nanomaterials. In this general area, there is perhaps a greater need for new measuring instruments and techniques than for new documentary standards, though the former, once developed, will need validation and verification and ultimately the preparation and delivery of standards covering the techniques and principles used. In the specific case of nanoparticles, it is not generally realized that particle size distribution is not a fundamental property of the material being studied, but a temporary state of dynamic equilibrium between dispersion and agglomeration in suspensions or aerosols. This, and numerous other differences between perception and reality, present tremendous challenges in such a high-profile subject area.