The International Organization of Standardization (ISO) defines a nanomaterial as a material with any external dimension measuring in the nanoscale, which is between 1–100 nm, or having any internal structure or surface structure in the nanoscale1.
Similarly, the ISO defines a nanoparticle as a nano-object that contains all three of its external dimensions measuring within this nanoscale1.
Nanomaterials are finding a wide variety of applications including next generation computer chips, improved insulating materials, low cost flat LED displays, elimination of pollutants, high energy density batteries, high power magnets, high activity sensors, aerospace components with enhanced performance characteristics, medical implants and much more2.
Based on the unique physicochemical properties of nanomaterials, they are classified into five different groups1. These groups include:
- Carbon-based materials, which can be either fullerenes, which have a spherical/ellipsoidal structure, or as graphene, that take the form of a tube or flake. The applications of this type of material can be found in electronics, films, coatings, etc.
- Metal based materials, which include quantum dots, metals and metal oxides such as gold, silver, platinum, titanium dioxide and copper oxide. These materials are used for their unique electromagnetic and optical properties.
- Dendrimers, which are nanoshaped branched polymers that are often used for drug delivery purposes.
- Self-assembled soft nanoparticles, which are formed by the self-assembly of individual molecules, which are also known as unimers.
- Composites, which include materials that are formed by the combination of nanoparticles with other materials or other nanomaterials that can enhance mechanical, thermal and barrier properties.1
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In 2009, the Federal Council of Switzerland authorized the Swiss National Science Foundation to carry out a five-year national research program (NRP 64) to analyze the opportunities and risks of nanomaterials with a budget of 12 million Swiss francs1,3.
In this initiative, twenty three research projects examined the opportunities and risks of nanomaterials that are involved in the various fields of biomedicine, environment, energy construction materials and food1,3.
These studies focused on the development, use, behavior and degradation of engineered nanomaterials in an effort to further the understanding of the potential benefits and undesirable effects of these materials1,3.
Nine of the 23 projects employed in this initiative focused on the application of nanomaterials for biomedical purposes such as for drug delivery purposes. An example of this application involves the use of nanomaterials in fighting viruses, as well as their use as immune modulators in a potential vaccine against asthma1,3.
Other promising projects derived from the NRP 64 include potential new drug therapy options that are based on nanoparticles that are capable of crossing the placental barrier, nanomagnets for the filtration of harmful metal substances from blood, nanomaterials based on nanocellulose or nanofibers that has the potential to be used as a bone or cartilage substituting material1,3.
The NRP 64 assessed the risk of nanomaterials by interpreting the potentially harmful mechanisms, the probability of exposure to such materials following environmental emissions, their potential persistence in the environment, their possible biological effects1,3.
The risk assessment of these nanomaterials was calculated as the product of hazard/toxicity and exposure time to the hazardous chemical1. While a majority of the 23 projects examined the inhalation toxicity of nanoparticles, two of them focused on the risk of toxicity associated with nanomaterials following their ingestion3.
Seven out of the 23 projects studied the fate of the engineered nanoparticles and how they spread along their life cycle to study the toxicity, degradability, stability and accumulation of nanomaterials within biological organisms, as well as in the environment1,3.
One of the most promising studies conducted in Switzerland determined that 95% of silver nanoparticles that are washed out from textiles end up in the sewage treatment plants, while the remaining 5% are deposited into the sewage sludge that is eventually incinerated3. Similarly, a measurement device that determines how the nanoparticles are accumulated in aquatic organisms was developed in another study3.
- "Engineered Nanomaterials: Impact & Safety Aspects." The Swiss National Science Foundation. Feb. 2017. Web. http://www.nrp64.ch/SiteCollectionDocuments/White-Paper-NFP64-E.pdf.
- Nanomaterials and Their Applications." AZoM.com. 11 June 2013. Web. http://www.azom.com/article.aspx?ArticleID=1066.
- "A Better Understanding of Nanomaterials." Phys.org. Web. https://phys.org/news/2017-04-nanomaterials.html.
- Image Credit: Shutterstock.com/Giroscience