17 November, 2008

Nanoparticles the Asbestos of Our Time?

Researchers in Finland and the US studied how carbon-based nanoparticles interact with cells. Results indicated that nanoparticles may alter cell structure, causing critical damage to cell functions. Nanoparticles may be the asbestos of the twenty first century: a considerable threat to people's health.

The research showed that healthy cell cultures are unaltered when exposed to fullerenes. The same cells are not impacted by exposure to gallic acid, an astringent component of tannins found in almost all plants.

When present in the cell culture at the same time, fullerenes and gallic acid interact to form structures which bind to the cell’s surface causing cell death. This property may be useful in cancer treatment, if such cells could be targeted to the exclusion of healthy cells. Some early studies indicated the hope of targeted delivery of chemotherapy drugs through nanoparticles. The study, however, only surveyed the nanoparticles without the chemical enclosed in it.

Research generated excitement in 2006, when the destructive nature of certain nanoparticles were fused, then found to destroy the cell membranes of cancer cells. In the culture, healthy cells were less effected by the destruction. The study suggested that these nanoparticles be used to enclose chemotherapy agents, thus target the cancer cells more directly.

The current research, however, demonstrates how difficult it is to map out the health effects of nanoparticles. 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.

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 or one millionth of a millimeter.

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 causing an arc between two graphite rods to burn in a helium atmosphere. 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. Currently, all sorts of nanoparticles are widely used in cosmetics, electronics, optical devices, medicine, and in food packaging materials. There are also significant amounts of nanoparticles in exhaust emissions.

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

Not all changes are beneficial. For instance, iron, at the nano level, switches its polarity using energy derived from room temperature heat, thus are not useful for data storage, as had been hoped. Their crystalline structure change when they get wet. So numerous questions have been raised about their safety and suitability, especially for products destined for human contact. This current study casts an even bigger shadow on the use of nanoparticles. This study stands out in its investigation into nanoparticles’ interactions with other substances.

A great deal of research looks into finding useful purposes for these nanoparticles. However, very little is known of their health effects. Only a tiny allotment of research into nanoparticles focuses on their health and safety risks. 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.

Since the number of possible combinations of nanoparticles and various biomolecules is immense, it is practically impossible to research them systematically.


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)

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