Background and Outcome
Nanomaterials and nanotechnology-enabled products have to be safe. It is imperative that they do not harm humans or the environment.
As more and more nanotechnology-enabled products enter the market, the importance of adequately assessing nanomaterial (NM) release, exposure, biokinetics, hazard and risk is now widely recognized. Given the large number of nanotechnology-enabled products entering the market, hazard and risk assessment of each and every single variant of nanomaterial is impracticable and undesirable for both economic reasons and the legal requirement to reduce animal testing.
To address this topic from a practical view the European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) established a Task Force on Nanomaterials (ECETOC Nano TF). The goal of the Task Force was to ensure that society can benefit from safe nanotechnology-enabled products by providing efficient safety assessments but requiring the least possible number of experimental animals.
The ‘grouping’ concept developed by the ECETOC Nano TF aims at making the hazard assessment of nanotechnology enabled products more efficient by using a grouping concept to bring together substances with similar toxicological profiles Currently while the topic of grouping of nanomaterials is addressed in different publications and some preliminary guidance is available in the context of substance-related legislation and occupational settings there are however no specific regulatory frameworks for grouping of nanomaterials. In an extensive review, the ECETOC Nano TF assessed all available concepts for the grouping of nanomaterials for human health risk assessment. Based upon this review, the ECETOC Nano TF proposes a functionality-driven Decision-making framework for grouping and testing nanomaterials (DF4nano) that aims to group nanomaterials by their specific mode-of-action. The value of the nanomaterial decision-making framework for hazard assessment has been substantiated by using it in case studies of 24 materials. The case studies confirmed the usefulness of DF4nano in that all materials with potential to be hazardous in vivo were recognized in the non-animal tiers of the DF4nano. The framework also proved to be efficient in sorting nanomaterials that
- could undergo hazard assessment without further testing,
- merit in-depth investigations
It also provides solid rationale for sub-grouping including specifying any needs for further information.
The ECETOC Nano TF has published the outcome of its work in three articles which have already been widely respected. These Open Access articles were printed in regular issues of Regulatory Toxicology and Pharmacology and were also captured in a special issue of the journal.
ECETOC believes this is the first comprehensive and pragmatic approach to the grouping and safety assessment of nanomaterials that has been presented to the scientific community. As with all innovative, new approaches the framework is expected to attract both praise and criticism some justified others unjustified. The ECETOC organisation that sponsored development of the framework has a history of tackling issues on the frontiers of scientific based risk assessment and regulation and as with all transparent and open science-based organisations is open to discussions on how to refine and enhance the approach and foster its application.
 ECETOC Workshop on Societal Aspects of Nanotechnology, 9 November 2005, Barcelona. Workshop Report No. 8, published by ECETOC, Brussels, October 2006.
 Arts J, Hadi M, Keene A, Kreiling R, Lyon D, Maier M, Michel K, Petry T, Sauer U, Warheit D, Wiench K, Landsiedel R. 2014.
A Critical Appraisal of Existing Concepts for the Grouping of Nanomaterials.
Regulatory Toxicology and Pharmacology 70(2):492-506 [Open Access]
 Arts J, Hadi M, Irfan MA, Keene AM, Kreiling R, Lyon D, Maier M, Michel K, Petry T, Sauer UG, Warheit D, Wiench K, Wohlleben W, Landsiedel R. 2015.
A decision-making framework for the grouping and testing of nanomaterials (DF4nanoGrouping).
Regulatory Toxicology and Pharmacology 71(2):S1-S27 [Open Access] Doi:10.1016/j.yrtph.2015.03.007
 Arts J, Irfan MA, Keene AM, Kreiling R, Lyon D, Maier M, Michel K, Neubauer N, Petry T, Sauer UG, Warheit D, Wiench K, Wohlleben W, Landsiedel R. 2015.
Case studies putting the decision-making framework for the grouping and testing of nanomaterials (DF4nanoGrouping) into practice.
Regulatory Toxicology and Pharmacology 76:234-261 [Open Access]
 Oomen, Agnes G., et al. “Grouping and read-across approaches for risk assessment of nanomaterials.” International journal of environmental research and public health 12.10 (2015): 13415-13434.
And Godwin, Hilary, et al. “Nanomaterial Categorization for Assessing Risk Potential To Facilitate Regulatory Decision-Making.” ACS nano 9.4 (2015): 3409-3417.