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VeilleNanos - Defining nanos

Defining nanos

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Defining the term “nanos” – When the size defines the object

By the AVICENN team – last modification in November 2024

Nanoparticles, nano-objects, nanomaterials: the terms referring to the nano world are multiple, complex, but not always interchangeable! It is important not to confuse them. While some refer to the physicochemical characteristics of nanos, others are regulatory definitions that change depending on the sector and country.

Some important concepts

Nanoparticle < Nano-object ≠ Nanomaterial

A distinction is made between a “nanomaterial” (which has different scientific and regulatory definitions) and a “nano-object”, a material with one, two or three* dimensions at the nanometric scale.

*When they have three nanometric dimensions, nano-objects are considered “nanoparticles”

Primary particle, agglomerate and aggregate

Nano-objects tend to group together to form larger sets called aggregates and agglomerates.

Several definitions for nanomaterials

Coexistence of different regulatory definitions

At the international level, several definitions of nanomaterials co-exist with different criteria (ISO, OECD, Scenihr, SCCP, European Regulations, ACC, etc.)1See more details in the following publications:
Comparative assessment of nanomaterial definitions and safety evaluation considerations, Boverhof DR et al, Regul Toxicol Pharmacol, 73(1):137-50, October 2015
Fact sheet on the definition of nanomaterials, CIEL, ECOS, Öko-Institut e.V., November 2014
– Annex 2 “Review of existing nanomaterial definitions” of the report Evaluation des risques liés aux nanomatériaux – Enjeux et mise à jour des connaissances, ANSES, April 2014 (put online on May 15, 2014)
. As an example:

  • The International Organization for Standardization ( ISO ) defines a nanomaterial2Cf. ISO/TS 80004-1, ISO, 2015 as “a material of which at least one external dimension is at the nanoscale or which has an internal or surface structure at the nanoscale” (the nanoscale being presented as “approximately” between 1 and 100 nm). It adopted the term NOAA to encompass all “Nano-Objects, their Agglomerates and Aggregates greater than 100 nm”.
  • The European Commission’s 2022 definition recommendation is not legally binding, but it is intended to be included, like the 2011 recommendation it replaces as a recommendation, but that is still in place in several regulations at the European level (REACH , Biocides and Medical devices) and French (mandatory declaration R-nano).
    It is more restrictive: unlike the ISO, it excludes internally structured nano- materials.
    While waiting for the finalization of a Joint European Research Center (JRC) guide for the 2022 recommendation, it is possible to refer to the guide published in 2020, “the NanoDefine Methods Manual“. In this document, the JRC provided terminological and methodological clarifications for determining whether or not a material falls within the 2011 definition. Its inclusion in the Novel Foods Regulation was rejected in April 2024 by the European Parliament.

What are the consequences?

The co-existence of different definitions complicates the work of producers / importers / distributors who must:

  • declare their nanomaterials to the health authorities, as is the case in France (r-nano register) and in other European countries as well and at the EU level (Reach)
  • label them differently depending on the sector of use (cosmetics, biocides, food).

Nevertheless, the problems related to the coexistence of different definitions ultimately concern mainly the ingredient suppliers. Indeed, when the characterization of the substances is done in a complete and adequate way upstream and transmitted correctly to the downstream stakeholders, these can use the definition appropriate to their sector and implement the necessary labeling and notification(s).

This situation could have been avoided if the project for a European register of nanomaterials with a harmonized definition at the Community level had not been hindered by the European Commission under pressure from industrial federations.

In the meantime, the temptation is great for many industrial groups to adopt avoidance strategies, with the use of nanomaterials whose size and distribution in number can flirt with the thresholds (with less than 50% of particles exceeding 100 nm for example) in order to escape the regulations while retaining the desired properties…

Elsewhere on the web

Any questions or comments? This information sheet compiled by AVICENN is intended to be completed and updated. Please feel free to contribute.

Upcoming Nano Agenda

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NAM to study epithelial perturbations in carbon nanomaterial-induced lung inflammation (EUROTOX, Online)
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  • Speaker: Carola Voss (Helmholtz Zentrum München)
  • Registration form

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Understanding Nanoscience (Paris Saclay University, Online)
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  • Public who has carried out two or more years of scientific studies at university, as well as professionals or the self-educated who want to discover, learn more or acquire specific knowledge in some area of nanoscience.
  • Organizer: Paris Saclay University
  • Course paln:
    • Theme 1: Introduction to nanoscience and nanotechnology – Let’s lay the foundations and discover the key concepts of this field.
    • Theme 2: How can you “see” and fabricate nano-objects? We will discover what tools are used to observe matter at these scales and what techniques the scientist can use to make objects that are only a few billionths of a meter in size.
    • Theme 3: Nanochemistry – From carbon to porous solids and nanoparticle synthesis; applications of the field.
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    • Theme 5: Nanobiology, Nanomedicine, Micro-nanofluidics – The study and manipulation of molecules; treating diseases with nanomedicine; the on-chip manipulation of liquids for medical diagnosis; applications of the field.
    • Theme 6: Nanoscience and Society: Are Nanotechnologies dangerous? Societal, health and environmental issues.
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Controlling the risks associated with nanomaterials (CEA, Online)
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  • E-learning program: awareness-raising for personnel who come into contact with nanomaterials during research, formulation, production, maintenance, cleaning, upkeep, etc., as well as safety coordinators or engineers, facility managers, heads of laboratories where nanoparticles are handled.
  • Organizers: INSTN Grenoble (CEA)
  • On the program:
    • 1 – Introduction, definition and characteristics of nanomaterials
    • 2 – Toxicity of nanomaterials: the state of knowledge
    • 3 – Metrology and characterization of nanomaterials
    • 4 – Prevention and protection against nanomaterials in the workplace
    • 5 – Quiz: assessment of learning outcomes
  • The 2-hour course can be viewed for one month from the date of registration.
  • Website: https://instn.cea.fr/…risques-lies-aux-nanomateriaux…

This sheet was originally created in April 2011


Notes and references

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