What makes a cookie the delicious treat it is? Size? Shape? Ingredients?Amount of chocolate chips? Your treat might not even be called a
cookie, as the definition is dependent on where you live. After all, is an
oatmeal raisin cookie REALLY a cookie?
Same with nanoparticles: there are different shapes, sizes,
compositions, and definitions. Nanomaterials are complexly variable, so
a standard definition has been difficult to pin down. (See list for some
examples). Since they are so complex, nanomaterials can be classified
according to source, dimensions, chemical composition and potential
toxicity.² To put it succinctly: “nanoparticles” and “nanomaterials” are
terms, often used interchangeably, to describe a substance that is
manufactured and used at the nanoscale.
Scientists use the term nanoscale to refer to the tiny size of nanomaterials and nanoparticles. Nanoscale typically refers to the range of 1 to 100 nanometers (nm), often according to regulatory purposes. However, particles or bundles of particles larger than 100 nm are still “nano ” and should be treated as such. The EU and the ISO have very specific definitions in this regard while other bodies like the CDC have more ambiguous definitions ( 2,3,4) You can see the ambiguity of meaning sometimes in the way these institutions are approaching regulation of nanoparticles. 1 x 109 meters, a nanometer, is one-billionth of a meter. We know that can be hard to grasp if you don’t keep an eye on nanotechnology, so to give you an idea on the measure of the nanoscale we are talking about we did some fun math for comparisons:
If a chocolate chip is a nanoparticle then a 3 inch cookie would be as tall as 4 Mount Everest’s. We get that not everyone bakes, but everyone bathes! So, if a nanoparticle is the size of a bar of soap, then a bathtub would be the size of the earth.
Just like cookies can be cut or formed into different shapes, the shapes of nanomaterials are diverse: rods, wires, spheres, diamond-shapes, stars/flowers and more (1,12). The final shape of the nanomaterial depends on the ingredients (composition), temperature and the overall manufacturing process. Although nanomaterials are quite variable, nanoparticles do have the basic anatomy of core and a surface coating.
Core: One or more metals, with atoms in an ordered and uniform grid-like structure (lattice). Some NPs are not made out of metal but that’s a story for another day.
Surface Coating: These are layers of atoms or molecules made of various substances like metals, silica, or other molecules; the surface coating stabilizes the particle (passivation).
The combination of core composition, of surface coating composition, shape, and size dramaticallychange the behaviour of a nanomaterial in a living organism or for any technical purposes.
Now that you’ve learned a bit about nanomaterials, nanoparticles, nanoscale and the basic structure of a nanoparticle, get yourself a cookie. While you are treating yourself, go learn about our mission to measure nanomaterials for the good of all. “Mmmm cookie.”
1. Dolez, P. I. Nanomaterials Definitions, Classifications, and Applications. In Nanoengineering; Elsevier, 2015; pp 3–40.
https://doi.org/10.1016/B978-0-444-62747-6.00001-4.
2. ISO/TS 80004-2:2015(en), Nanotechnologies — Vocabulary — Part 2: Nano-objects https://www.iso.org/obp/ui/#iso:std:iso:ts:80004:-2:ed-1:v1:en (accessed Jul 7, 2020).
3. Part 1: Mech et al., The NanoDefine Methods Manual. Part 1: The NanoDefiner Framework and Tools, EUR 29876 EN, Publications Office of the European Union, Luxembourg, 2019, ISBN 978-92-76-11950-0, doi:10.2760/55181, JRC117501
4. Nanotechnology | NIOSH | CDC https://www.cdc.gov/niosh/topics/nanotech/default.html (accessed Jul 9, 2020).
5. Frequently Asked Questions: Nanotechnology | NIOSH | CDC https://www.cdc.gov/niosh/topics/nanotech/faq.html (accessed Jul 7, 2020).
6. OSHA Fact Sheet: Working Safely with Nanomaterials – OSHA 3634 | Occupational Safety and Health Administration
https://www.osha.gov/Publications/OSHA_FS-3634.html (accessed Jul 9, 2020).
7. Frequently Asked Questions | Nano https://www.nano.gov/nanotech-101/nanotechnology-facts (accessed Jul 14, 2020).
8. Guidance for Industry Considering Whether an FDA-Regulated Product Involves the Application of Nanotechnology. Biotechnology Law Report 2011, 30 (5),
613–616. https://doi.org/10.1089/blr.2011.9814.
9. Canada, H. Policy Statement on Health Canada’s Working Definition for Nanomaterial
https://www.canada.ca/en/health-canada/services/science-research/reports-publications/nanomaterial/policy-statement-health-canada-working-definition.html (accessed Jul 9, 2020).
10. Government of Canada, C. C. for O. H. and S. Nanotechnology – General : OSH Answers https://www.ccohs.ca/ (accessed Jul 14, 2020).
11 Lauterwasser, C. Small Sizes That Matter: Opportunities and Risks of Nanotechnologies Report in Co-Operation with the OECD International Futures Programme; OECD, Allianz Center for Technology.
12. Xia, Y.; Xiong, Y.; Lim, B.; Skrabalak, S. E. Shape-Controlled Synthesis of Metal Nanocrystals: Simple Chemistry Meets Complex Physics? Angew. Chem. Int. Ed. 2009, 48 (1), 60–103. https://doi.org/10.1002/anie.200802248.