Nanodeeltjes en
uw gezondheid?*
Italiaanse wetenschappers waarschuwen tegen de mogelijke nadelige gevolgen van het gebruik van nanodeeltjes waaronder koolstofnanobuizen. De toepassingsmogelijkheden zijn zo groot waardoor de techniek van nanodeeltjes snel op grote schaal toepassing zal gaan vinden, terwijl op nauwelijks nog gekeken wordt naar de mogelijk schadelijke gevolgen op lange termijn. Verschillende wetenschappers hebben al mogelijke problemen gesignaleerd. Zo zouden carbonnanodeeltjes dezelfde risico’s kunnen geven voor het menselijk lichaam als fijnstof en asbest. Belangrijk is het dus volgens de wetenschappers dat het onderzoek na de nadelige gevolgen geďntegreerd wordt in het ontwikkelingsproces.
Een nadelig affect van nanodeeltjes blijkt al uit de volgende Britse studie.
Metalen nanodeeltjes die uit botimplantaten lekken, blijken schadelijk voor het lichaam. De piepkleine deeltjes maken cellen kapot zonder ze binnen te dringen. Ze doen hun destructieve werk dus op afstand. Dat hebben Britse wetenschappers ontdekt. Botimplantaten zijn roestvrijstalen pinnen of staven om botten bij elkaar te houden. Ze zijn samengesteld uit kobalt en chroom. De implantaten kunnen een beetje giftig zijn. De wetenschappers vermoedden dat de giftigheid ontstaat doordat kleine metaaldeeltjes uit de pinnen of staven lekken. Ze plaatsten piepkleine kobalt-chroomdeeltjes in de buurt van een groepje menselijke cellen. Het DNA liep daardoor schade op. Ze ontdekten ook dat de metaaldeeltjes niet echt in contact kwamen met het celmateriaal, maar dat ze van enige afstand wel schade aanrichtten. Hoe dat precies in z'n werk gaat, is niet helemaal duidelijk. De wetenschappers vermoeden dat de onder invloed van de nanodeeltjes de cellen een overschot van een bepaald molecuul gaan produceren dat schade veroorzaakt aan het DNA. Een ding weten de wetenschappers nu wel zeker: metalen nanodeeltjes uit botimplantaten zijn niet goed voor het menselijk lichaam.
Researchers outline the long-term safety of carbon nanotubes in a journal
Italian scientists suggest that we need a much more detailed toxicological approach to hazard assessment before judgement regarding the long-term safety of carbon nanotubes can be made. They outline their results in the International Journal of Environment and Health.
Although nanotechnology is a relatively new field of research, already there are claims that its products could be harmful to human health and damaging to the environment. In particular, concerns have been raised about the safety of carbon nanotubes, minute hollow fibres of the carbon. Carbon nanotubes are just one group of materials being developed under the umbrella term of nanotechnology, which focuses on materials comprising particles between 1 and 100 nanometres in size. A nanometre is a billionth of a metre.
According to Enrico Bergamaschi of the Department of Clinical Medicine, at the University of Parma Medical School, carbon nanotubes are among the most promising nanomaterials, with potential in engineering, molecular electronics and as drug-delivery agents that could significantly reduce side-effects for countless medications.
In spite of their innovative properties, the small size of carbon nanotubes has led some observers to hypothesize that they may have similar detrimental effects to the sooty particles from vehicle exhausts known as PM10 particulates. Others suggest that toughness and fibrous nature of carbon nanotubes is reminiscent of asbestos fibres and follow the same fibre paradigm.
Bergamaschi and colleagues point out that carbon nanotubes are a recent invention only now finding commercial applications and so clinical and epidemiological evidence for any long-term effects they may have on human health are entirely lacking.
The researchers explain that, despite the occasionally exaggerated headlines seen in the media regarding research studies into the effects of nanotechnology, their novelty means that no one has yet established whether they represent a long-term health risk, or whether they can exacerbate certain pre-existing medical conditions.
"As more of these materials are produced, there is an urgent need to refine strategies to assess their possible effects on employees who represent the main exposed population, along with characterizing exposure, so that appropriate safety regulations can be put in place if needed," says Bergamaschi.
Accepted and standardised tests and models have been set up and are in place to allow for an evaluation of any new chemical or material against existing benchmarks and to categorise their associated risk level, the team explains. However, we don't know whether they also work for such a heterogeneous class of nanomaterials.
As such, researchers have already demonstrated acute toxic effects caused by inhalation of carbon nanotubes. Several teams have focused on the way these substances interact with our cells at the molecular level. Their small size and surface chemistry and reactivity are the most important factors affecting their biological interactions and toxicity as they could remain intact in the lung or, after systemic translocation, in other organs for extended periods. However, it is common to modify the surface of carbon nanotubes for specific applications by adding different chemical groups. On one hand this seems to reduce cytotoxicity, and increase their metabolic clearance, but on the other doesn't necessarily allow cells to break down such structures more readily.
Nevertheless, the Parma team, having reviewed all the available data, suggests that in order to meet an acceptable level of certainty regarding the safety or otherwise of carbon nanotubes, we should combine experimental, clinical and epidemiological evidence. They add that it is time to set up preventive measures as well as assess the need to implement periodic health examinations of employees exposed to carbon nanotubes.
http://www.unipr.it/
Nanoparticles can cause DNA damage across a cellular barrier
Gevdeep Bhabra1,10, Aman Sood1,10, Brenton Fisher1, Laura Cartwright2, Margaret Saunders2, William Howard Evans3, Annmarie Surprenant4, Gloria Lopez-Castejon4, Stephen Mann5, Sean A. Davis5, Lauren A. Hails5, Eileen Ingham6, Paul Verkade7, Jon Lane7, Kate Heesom8, Roger Newson9 & Charles Patrick Case1
Abstract
The increasing use of nanoparticles in medicine has raised concerns over their ability to gain access to privileged sites in the body. Here, we show that cobalt–chromium nanoparticles (29.5 6.3 nm in diameter) can damage human fibroblast cells across an intact cellular barrier without having to cross the barrier. The damage is mediated by a novel mechanism involving transmission of purine nucleotides (such as ATP) and intercellular signalling within the barrier through connexin gap junctions or hemichannels and pannexin channels. The outcome, which includes DNA damage without significant cell death, is different from that observed in cells subjected to direct exposure to nanoparticles. Our results suggest the importance of indirect effects when evaluating the safety of nanoparticles. The potential damage to tissues located behind cellular barriers needs to be considered when using nanoparticles for targeting diseased
states.
1. Bristol Implant Research Centre, Southmead Hospital, Bristol BS10 5NB, UK
2. Biophysics Research Unit, Department of Medical Physics & Bioengineering, Bristol Haematology & Oncology Centre, University Hospitals Bristol NHS Foundation Trust, Horfield Road, Bristol BS2 8ED, UK
3. Department of Medical Biochemistry and Immunology & Wales Heart Research Institute, Cardiff University, Cardiff CF14 4XN, Wales
4. Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
5. School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
6. Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
7. Department of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
8. School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK
9. Medical Statistics, National Heart and Lung Institute, Imperial College London SW7 2AZ, UK
10. These authors contributed equally to this work
(November
2009)
