What does the term “nano” mean?
Nanoparticles are particles with a size (height, width or length) of 1 to 100 nm (nanometers). To clarify the size: A nanometer is one millionth of a millimeter.
“Nano” is derived from the Greek term nanos and means dwarf. This refers to the small size of the particles.
What health risks do nanoparticles pose?
Nanotechnology is still in its infancy and much research work is still needed, so that a general risk assessment cannot (yet) be made.
Various factors come into play, such as whether the particles are firmly bound or whether they are present in free form. In addition, the hazard must be assessed on a substance-specific basis .
A major point of risk is absorption into the body. This can occur via the respiratory tract, for example. The problem: similar to A-dust and asbestos, nanoparticles (e.g. carbon nanoparticles) can penetrate the alveoli (pulmonary alveoli) and cause serious inflammation of the lung tissue.
Absorption can also occur through the gastrointestinal tract. Almost no studies are available on the consequences of this absorption. However, the particles can enter the bloodstream.
Nanoparticles are already widely used in numerous cosmetic products. An intact protective skin layer provides a solid barrier so that the particles cannot penetrate into deeper layers of the skin. However, if wounds are present or there is contact with the mucous membranes, entry can take place.
There is often a lack of appropriate test methods to define the effects on the body. As nanoparticles are much smaller than blood cells (8 micrometers) , they are transportable in the bloodstream. Therefore, transfer of the particles into the placenta during pregnancy cannot be ruled out.
Many unanswered questions remain about the effects of nanoparticles:
- Is there a risk of the substances being deposited in the body?
- What effects can this have on the fetus?
- Can degradation products occur and what effects do they have on the body?
- What influence do the particles have on the blood circulation and the cell system?
Occurrence of nanoparticles
Nanoparticles can occur naturally (combustion processes) or be produced synthetically . There are various methods for this: Gas phase synthesis or by the so-called sol-gel process or also by comminution processes.
Nanoparticles are used extensively in medicine, cosmetics, technology and surface coatings (e.g. for glasses: increased scratch resistance)
Nanotechnology is still in its infancy. As some materials change their properties as soon as they are reduced to nano size, this opens up an incredible amount of potential. For example, ceramics become flexible or other materials suddenly conduct electricity as nanoparticles. On the one hand, this is due to the enormous increase in surface area for the same total volume. On the other hand, nanoparticles react much faster and more violently (as there is a larger reaction surface) and such properties are to be used with the greatest possible benefit.
Use of nanoparticles
Where nanoparticles are already found, for example, are impregnation sprays or sun creams (titanium or zinc oxide). The protective effect lies in the surface structure. The coating potential is also utilized in other areas. For example, the use of nanoparticles can significantly reduce the amount of material used and thus save energy and material.
There are also many potential applications in medicine. For example, nanoparticles can be used to transport active ingredients in a more targeted manner, as they can pass through the blood-brain barrier, making therapies minimally invasive. It is also possible to use particles with an antimicrobial effect (e.g. silver) , which can curb the spread of germs.
Unanswered questions about the dangers of nanoparticles
Despite the research, some questions remain unanswered, particularly on the subject of potential hazards. Meanwhile, many studies refer to the impact on water bodies and aquatic organisms, as it is assumed that the increasing use of silver particles in everyday life (e.g. functional clothing) has led to an increase in silver in wastewater. The question remains as to what influence this has on the sewage sludge and the microorganisms required for wastewater treatment.
Another issue is the lifetime of the particles and what happens when they are used or decompose. What interaction with other (nano)materials is possible?
The labeling of products containing nanotechnology is not yet uniformly regulated; meanwhile, “nano” must be declared after the substance in question in the list of ingredients.
There is also still a lack of far-reaching regulations in the area of occupational safety. In many cases, they are comparable to dusts or fibers, but there is no OEL, for example.
Unintentional release must be avoided during production, as the particles spread very quickly and widely throughout the room.
Despite all the concerns, there remains a positive trend for the future of nanoparticles. Intensive research is being carried out to find solutions to issues such as hazardous substance measurement or the effects on the body.
Sources:
[1]: Source Featured image: © Kateryna Kon / 123RF.com
[2]: https://www.nanopartikel.info/
[3]: https://www.bund.net/themen/chemie/nanotechnologie/
[4]: https://www.umweltbundesamt.de/nanopartikel
[5]: https://www.chemie.de/lexikon/Nanoteilchen.html
[6]: https://www.test.de/Nanoteilchen-Das-sollten-Sie-wissen-4445980-0/
[7]: https://www.lungeninformationsdienst.de/forschung/nanopartikelforschung/nanopartikel-im-portraet/index.html
[8]: https://www.bghm.de/arbeitsschuetzer/fachinformationen/gefahrstoffe-und-biologische-arbeitsstoffe/nanopartikel-und-ultrafeine-partikel/
[9]: https://www.dguv.de/ifa/fachinfos/nanopartikel-am-arbeitsplatz/index.jsp
[10]: https://www.umweltbundesamt.de/sites/default/files/medien/publikation/long/3765.pdf