Carbon nanotubes could be harmful for human health and for the environment

Mar 26, 2007 13:01 GMT  ·  By

Nanomaterials are regarded as a great hope for many medical fields, like fighting against tumors.

But as in the case of every new technology, the size, type, and dispersion of nanomaterials are not well understood in how they could impact human health and the environment.

Two new researchers at Rensselaer Polytechnic Institute have investigated this.

While carbon nanotubes inhibited growth in mammalian cells but they stimulated it in common bacteria.

The contradictory discoveries warn about the necessity of a better understanding on how these small particles could impact the environment or the human body.

The first research led by Assistant Professor of Biomedical Engineering Deanna M. Thompson focused on the impact of carbon nanotubes on the development of rat heart muscle cells, in order to assess how nanotubes affect mammalian (and ultimately human) cells, tissue and organs.

This research watched the impact of both clusters and finely dispersed bundles of nanotubes and other nanoparticulate impurities. The finely dispersed material, despite its low concentration, impeded animal cell growth more than larger nanotube clusters. Activated carbon (a nanoporous material) was found to present a lower impact on the cells than any type of nanotubes.

The second approach, led by Anurag Sharma, assistant professor of earth and environmental sciences, focused on bacterial growth (for the species Escherichia coli) in the presence of carbon nanotubes or on the impact of nanotubes on the environment on long term.

The nanotubes were found to enhance the bacterial growth but they also provoked sometimes a considerable elongation of the E. coli, which can be seen as a stress effect. This reaction was not seen with other carbon nanomaterials like activated carbon or C60 fullerenes (buckyballs). "It appears that in order to see a real environmental impact of nanomaterials, a significantly long duration study similar to ours is needed to get further insight into the physiology of biological interactions in general, and bacterial interactions in particular," said Pavan Raja a doctoral candidate in chemical and biological engineering who worked on both research teams.

These researches point to the fact that different nanomaterials could have a deep impact on human health and the environment. "These findings highlight the underlying need for further research to correlate in detail the different types of nanomaterials and their modes of interaction with biological systems, to promote safe and optimized applications of nanotechnology," said Raja.