Nanoparticles, Asbestos of Our Time? (revised)

Researchers in Finland and the US studied how certain nanoparticles interact with cells. Results indicated that nanoparticles may alter cell structure, causing the cells to die. Currently, nanoparticles are widely used in cosmetics, electronics, optical devices, medicine, and in food packaging materials. Nanoparticles may well be the asbestos of the twenty first century: a considerable threat to people`s health.

Nanotubes were discovered accidentally in 2000 at Heidelberg University, in Germany. By nature they seem to be a means of cell to cell communication. They exist for very short periods of time, then vanish as the cells no longer need them.

Nanoparticles (also known as nanopowders, nanoclusters, nanotubes, or nanocrystals) are microscopic. They measure less than 100 nanometers in at least one dimension. A nanometer equals one billionth of a meter – one millionth of a millimeter.

Although we are used to substances having particular properties, those properties often change as the particle size approaches the nano level. Theories suggest that the change in properties is related to the percentage of atoms at the surface of the substance. These different properties are fascinating to scientists.

Not all changes are beneficial. For instance, iron, at the nano level, switches its polarity using energy gained from room temperature heat, thus they are not useful for data storage, as had been hoped. Some nanoparticles’ crystalline structure changes when they get wet. So numerous questions have been raised about their safety and suitability, especially for products destined for human contact

Scientists found ways to manufacture stable nano-sized particles in various forms. Given the transient nature of the body’s own nanotubes, the very stability of the synthetic particles may pose a threat.

A great deal of research looks into finding useful purposes for man made nanoparticles. However, very little is known of their health effects, especially their down side. Only a tiny allotment of research into nanoparticles focuses on their risks to health and safety. While the use of nanoparticles in consumer products increases, follow-up procedures and legislation lag behind. The European Union chemicals directive REACH does not even touch upon nanomaterials.

Research, presented in the nano journal `Small`, showed that cell cultures (colonies of a particular type of cell growing in a dish) are unaltered when exposed to fullerenes. The same cells do not react when exposed to gallic acid, an astringent component of tannins found in almost all plants. When present in the cell culture at the same time, however, fullerenes and gallic acid interact to form structures which bind to the cell’s surface causing cell death. The study did not focus on cancer cells.

Fullerenes are spherical, ellipsoid, or cylindrical nano-sized molecules of carbon atoms. They were named after Buckminster Fuller, creator of the geodesic dome. Fullerenes are produced by producing an eletrical arc through a vessel containing helium gas between two graphite rods. Ten percent of the resulting soot are these nanoparticles. The fullerene tubes and balls are extracted from the carbon soot by using an organic solvent called toluene. The U.S. Department of Energy is looking into using these fullerenes in the future. This study is one of the few cataloging the effects of these particles in the human body.

Researchers generated excitement in 2006, when the destructive nature of certain nanoparticles were found to destroy the cell membranes of cancer cells. In the culture used in the early experiments, healthy cells were effected, but less so than cancer cells. The researchers, in their excitement, suggested that these nanoparticles be used to enclose chemotherapy agents, thus target the cancer cells more directly.

The early study, however, only surveyed the nanoparticles in isolation, without the toxic chemicals enclosed in them. The current study casts a shadow on such use of nanoparticles. This study stands out in its investigation into nanoparticles’ unforseen interactions with other substances. Combining these particles which do not behave as we expect with the already dismal failure of chemotherapy seems like a recipe for disaster. The interaction of the man made nanoparticles with enclosed dangerous chemicals, not to mention with substances in the body’s environment, may present unexpected and fatal results.

The current research demonstrates how difficult it is to map out the health effects of nanoparticles. Since the number of possible combinations of nanoparticles and various biomolecules is immense, it is practically impossible to research them systematically. Even if a certain nanoparticle does not appear toxic, the interaction between this nanoparticle and other compounds in the human body may cause serious problems to cell functions. Further, combining nanoparticles with toxic substances poses even more serious questions. Be wary of products which tout the use of nanoparticles. This is yet another reason why consumers need to demand natural, organically grown ingredients in products.


References

http://www.eurekalert.org/pub_releases/2008-11/tuot-n111308.php

http://www.newscientist.com/article/mg20026821.400-tunnelling-nanotubes-lifes-secret-network.html?DCMP=OTC-rss&nsref=online-news

http://www.sciencedaily.com/articles/n/nanoparticle.htm

http://www.ch.ic.ac.uk/local/projects/unwin/Fullerenes.html

http://www.nanopharmaceuticals.org/files/Death_by_Nanoparticles_nanopharmaceuticals2.org_OCT_2006.pdf

http://nano.cancer.gov/news_center/nanotech_news_2006-10-16c.asp

E. Salonen, S. Lin, M. L. Reid, M. Allegood, X. Wang, A. M. Rao, I. Vattulainen, P.-C. Ke. Real-time translocation of fullerene reveals cell contraction. Small 4, 1986-1992 (2008)