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Monday 15 June 2009

RAPID ROUNDUP: Carbon nanotubes suppress the immune function (Nature Nanotechnology) - experts respond

Embargo lifted 3am AEST Monday 15 June 2009

New research shows how the inhalation of carbon nanotubes can suppress the immune function of mice. This finding highlights potential health concerns for those working with these materials. The study to be published on Monday in Nature Nanotechnology shows that inhalation of low levels of nanotubes causes activation and release of a signalling molecule from the lung that in turn produce a direct effect on the immune function of T cells — a class of white blood cells — in the spleen.

A fact sheet on carbon nanotubes is also available compliments of our colleagues at the UK Science Media Centre.

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Associate Professor Thomas Faunce is Director of the Globalization and Health Project and Associate Professor in the College of Law and Medical School at The Australian National University

“This paper suggests that inhalation of carbon nanotubes, as well as potentially causing a persistent inflammatory reaction resembling mesothelioma, at sufficient concentration may also produce a unique suppression of the systemic immune system. One needs to be cautious about overreacting to what is in many ways a preliminary finding but if this research is supported by subsequent studies it supports the case for specific exposure regulation applied to these nanoparticles.”

Prof Martina Stenzel is from the Centre for Advanced Macromolecular Design at the University of New South Wales

“I think what this article mainly shows is that we don't know enough about nanoparticles/nanotubes. With the introduction of nanoparticles in many areas of research including medical research it was thought to be the wholly grail to all our problems - nanoparticles for cancer treatment, for water treatment, for energy.....you name it. In the last few years, we have more and more voices emerging showing that there could be some toxic side effects. Fact is, we don't know enough about the nanoworld and much more research needs to be done to understand the
good and the bad effects of these little particles that have the size of a viruses - and yes, maybe we should treat nanoparticles at the moment more like a virus until we really know what the effects are.

However, after years of euphoria, we should not turn around and condemn nanoparticles. Nanoparticles have led to many promising results in our research labs. I am not too aware of other areas, but I am familiar with cancer treatment. Here we can use nanoparticles to sneak some cancer drugs into tumors. The nanoparticles are loaded with little anti-cancer drugs and these nanoparticles are not immediately detected by the body. Therefore, the efficacy of the treatment can be much higher. Cancer cells are very happy to take up nanoparticles and once they are inside the cell, they release their toxic cargo killing the cancer cell.

While this is a great concept, we can assume that nanoparticles may go into healthy cells, and the other problem we haven't answered yet is what will happen to the nanoparticles in the body once they have done their job. It seems that everything has two sides to it and we should alsways keep this in mind.

I think the paper is a nice addition to nanoresearch and shows that we should be careful with any new invention. It is not the first paper that looks into the toxicity of nanoparticles. However, we need to do more research in this area. From an application point of view, we also need to learn to balance between the great advantages nanoparticles can have with potential negative side effects.”

“Whilst this is an interesting immunological paper elucidating the cause of immune suppression by inhalation of carbon nanotubes in mice, I don't think that significant media attention is warranted. There are plenty of studies out there (some dating back more than 20 years) on the toxicology and immunology of inhaled dust particles produced (as a product or by-product) in plants to which workers might be exposed to. Examples range from wood-borne particles, metallic or polymeric dusts, many of those are on the nanoscale. I am not very familiar with the occupational health and safety regulations in these industries, but I am sure that there is personal protective equipment in place to effectively prevent inhalation of these particles by workers. The same is true for carbon nanotubes. I don't see any reason to be alarmed by these findings.”