Small enough to care and big enough to deliver

Definition of Nanomaterials

Nanomaterials are natural or manufactured substances with 50% or more of particles in the number size distribution containing particle sizes between 1 to 100 nm in at least one dimension.

Nanomaterials contain constituent particles:

  • in an unbound state
  • as an aggregate
  • as an agglomerate

Definition of Nanoforms

A substance may have one or more different nanoforms, based on differences in size, shape, surface treatment and functionalization as well as specific surface area. These parameters may influence the toxicological or ecotoxicological profile, exposure as well as behavior in the environment. Therefore, all the nanoforms of a substance have to be reported in the registration dossier.

Methods for the Characterization of Nanomaterials and Nanoforms

  1. TEM (Transmission Electron Microscopy) and/or SEM (Scanning Electron Microscopy)
  2. PSD (Particle Size Distribution)
    - for solids: freefall shaft
    - for liquids: wet dispersion
    - for aerosols: pump systems and aerosols under pressure
  3. FTIR
  4. XRF or ICP-MS
  5. XRD: X-ray diffraction
    Characterization of amorphous Nanoforms including quantification by Rietveld method
  6. BET (Brunauer–Emmett–Teller)
    Determination of specific surface by gas adsorption
  7. Zeta Potential
  8. Moisture and water: gravimetric method for solids and/or with Karl-Fischer method for liquids
  9. NMR

Determination of Physical-chemical Properties

The following studies are recommended to describe Nanomaterials:

  1. Water solubility (OECD 105)
  2. Water solubility for silica with Tyndall effect
  3. Transformation – Dissolution Study for inorganic Nanomaterials (OECD 29)
  4. Dispersion Stability of Nanomaterials in Simulated Environmental Media (OECD 318)
  5. Particle Size Distribution (PSD), angular laser diffraction for solids, liquids and aerosols
  6. Density: bulk density, tapped density or skeletal density
  7. Dustiness: calculation based on PSD and bulk density
  8. Point of Zero Charge: physical state, when the electrical charge density on a surface is zero
  9. Hydroxy groups acc. SEARS
    Determination of Specific Surface Area of Colloidal Silica by titration with sodium hydroxide

Ecotoxicology

Due to the expected long-term effects of nanomaterials, it is recommended to conduct the studies as chronic studies and, if possible, under flow-through conditions:

  1. Aquatic plant studies: Lemna (OECD 221)
  2. Invertebrates studies: Daphnia (OECD 211)
  3. Fish studies (OECD 210, OECD 212, OECD 215)
  4. Earthworm studies (OECD 222)
  5. Chironomus studies (OECD 218 and OECD 219)

Genotoxicity/Mutagenicity

Since the Ames study (OECD 471) is not recommended for Nanomaterials, Genotoxicity/Mutagenicity shall be evaluated using one or more in vitro studies on mammalian cells:

  • OECD 473: In Vitro Mammalian Chromosome Aberration Test
  • OECD 487: In Vitro Mammalian Cell Micronucleus Test
  • OECD 490: In Vitro Mammalian Cell Gene Mutation Test: Mouse Lymphoma Assay
  • OECD 476: Hypoxanthine-guanine phosphoribosyl transferase Test: HPRT Test

Endocrine Properties

LAUS can support you with the following studies for the assessment of your substance:

  1. Estrogen or Androgen Receptor Binding Affinity (YES/YAS Assay)
  2. Fish Early Life Stage (ELS) Toxicity Test (OECD 210)
  3. Chironomid Toxicity Test (OECD 218-219)
  4. Daphnia magna Reproduction Test (OECD 211)
  5. Earthworm Reproduction Test (OECD 222)
  6. Sediment Water Lumbriculus Toxicity Test using Spiked Sediment (OECD 225)
  7. Sediment Water Chironomid Life Cycle Toxicity test (OECD 233)
Please contact us for a customized proposal for Sameness/Substance Identity or an appointment to discuss your test strategy.