BAFU - Dokumentation - Nanopartikel dringen auch ins Gehirn vor

BAFU - Dokumentation - Nanopartikel dringen auch ins Gehirn vor

Nanoparticles penetrate well into the brain

Synthetic nanoparticles can penetrate tissue and cells and spread throughout the body - even in the brain. Professor Peter Gehr of the University of Bern - an internationally renowned fabric specialist - is surprised that you can hardly take the potential health risks outside the science and management of knowledge.

Interview: Kaspar Meuli

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Peter Gehr is Professor of Histology - the study of the tissues - and anatomy at the University of Bern. He has made an international reputation as a researcher, so among other things, his work on the behavior of nanoparticles in the lung and to interact with cells. Peter Gehr directs the National Research Programme NRP 64 "Opportunities and Risks of Nanomaterials" of the Swiss National Science Foundation. The necessary work will start in December 2010.

© Stefan Bohrer

Power, the Swiss population worries about the health effects of nanoparticles?

Peter Gehr: No, because either people have no idea what it is about, or they see no problem in it. The possible hazards are also in politics hardly an issue.

Why this unconcern?

Nanotechnology and manufactured with appropriate processes nanoparticles fascinate and have already produced positive applications, such as new materials. Thus, for example with carbon nanotubes very robust and extremely light materials manufacture. This weighs a few pounds less bicycle frames.

On the other hand, there are alarming reports, such as on Chinese workers who are suffering from severe lung problems at work because of high concentrations of nanoparticles.

Meanwhile, it has been shown that the corresponding study has serious flaws. When the media took up the issue in December 2009, I thought, however, now the mood would tip. I assumed that we Nano researchers must justify ourselves, because people are seriously concerned. But the newspaper article sparked no greater debate, and the subject was silted up within days. People react at the moment just not to the at best questionable sides of the artificial nanoparticles.

Hold for a researcher to strong concerns with your back?

No, on the contrary. I declare anywhere where the danger lies - in discussions with politicians, in public lectures and panel discussions: If nanoparticles are not closely involved in any material, there is a risk that we inhale. Then they can go through the lungs into the bloodstream and spread throughout the body. We do not yet know what consequences this has for health. But the fact that particles enter our body is problematic. Outside of science and management but this is apparently not noted.

Lay people are probably confused by the contradictory assessments of the opportunities and risks of this technology.

For over a year I am also confused enormous. In animal studies, it can be shown that nanoparticles penetrate tissues and cells and can spread via the bloodstream throughout the body - even in the brain. However, we still do not know exactly how this happens. Among researchers is spoken recently about the fact that nanoparticles, which come into contact with our bodies, are covered by a protein layer. This occurs at the latest when they reach the surface active film which coats the entire inner surface of the lungs. We still know very little about this so-called coating of the particles. So it is unclear how it is going exactly whether the protein coat is changed during penetration into the cells and the importance this has for the functioning of the cells. Here is where I see the greatest uncertainty about the health risks associated with nanoparticles.

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Nanoparticles can penetrate tissue and cells, and spread via the blood throughout the body. The one with the scanning laser microscope at the Institute of Anatomy, University of Bern realized close-up of red blood cells showing green nanoparticles, which have penetrated into these cells.

© Barbara Rothen-Rutishauser, Institut d'anatomie de l'Université de Berne

What do you say to studies that suggest carbon nanotubes are as dangerous as asbestos?
Of asbestos fibers is known that they can lead to the outer surface of the lungs to cancerous changes. There was now animal experiments with synthetic carbon tubes that are structured similarly of its duration ago. In experiments in the abdominal cavity of mice led by the introduced particles actually tumor-like enlargements, which are considered pre-cancerous. On the other hand caused carbon tubes whose shape and size are not to be compared with asbestos fibers, no such changes.
This result is reassuring or there is cause for concern?
I have over carbon nanotubes fundamental concerns - regardless of their form. The idea of ​​having to breathe in nano-or micrometer-large tube scares me. From these scenarios, we are by the way not that far away. On a nanotechnology conference in Japan has recently introduced Pneus, where carbon nanotubes to impart increased resistance. Assume that all cars were with such tires on the road, we would actually be a problem. The rubber and enclosed therein nanoparticles are abraded, weather and the carbon tubes into the air. So this idea is not unrealistic.
Already, the air we breathe is so loaded with fine dust. These particles act differently on our health as industrially manufactured nanoparticles?
No, because the main problem with the penetration of solid particles in our bodies is their size. It is much more important than the form or type of material from which they are made, as we were able to demonstrate at our institute. So-called PM10 particles that contain many nanoparticles, are all subject to the same physical mechanism by inhalation. You are wetted and then moved to the depth against the lung tissue.
If particulate matter in this regard therefore equally dangerous as artificial nanoparticles?
This is practically the same thing!
How problematic is the detection of nanoparticles in the brain?
We could in my lab using modern microscopes show that nanoparticles overcome in the lungs, the air-blood barrier. Similarly, they can also pass via the blood-brain barrier into the brain tissue, such as research colleagues have demonstrated in animal experiments using radioactive substances. It is indeed to vanishingly small amounts, but those are thousands of nanoparticles that penetrate in this way to the brain.
Could this cause damage?
I know the work of a colleague, who grew up in Mexico City and then worked in the leading centers for environmental research in the United States. She has studied the brains of people who have died of Alzheimer's. This compared it with the brain tissue of a young man who had lived all his life on a heavily traveled street in Mexico City and then was killed in an accident. I'll never forget the amazing parallels between the brain recordings. So-called beta-amyloid plates - - which are considered as precursor of Alzheimer's disease In both cases, the same inflammatory changes of the brain showed. Very pointedly, one could conclude that air pollution leads to Alzheimer's.
Is that safe?
No, for the moment are the hypotheses. But it raises actually several researchers question whether the pollution could not be a cause of Alzheimer's. If this were the case, then in all likelihood by the inhalation of particles to enter the bloodstream and have overcome the blood-brain barrier.

Contact: magazin@bafu.admin.ch
Last updated on: 27/08/2010