Scientist Smackdown: Can Nanoparticles Damage Human DNA?

By Brett Israel | November 9, 2009 5:52 pm

nanoparticles-web“Nanoparticles can cause DNA damage across a cellular barrier.” That’s the title of a paper published in Nature Nanotechnology that inspired a number of ominous news headlines (two examples: Nanoparticles ‘can damage DNA‘ and Nanoparticles can damage DNA at a distance: study). The stories that followed basically sang the same tune—that nanoparticles can damage our cells’ genetic material even from a distance (a relatively short distance of four cells away). However, experts are speaking up in response to the media hype, and argue that this study should have never been covered in the news. This particular study has little relevance to human exposure risks, experts say, and it is deeply flawed in other ways [ScienceNOW Daily News]. At least one expert called the study “meaningless,” however other scientists were more diplomatic and have pointed to a number of interesting questions the study raises that are worth pursuing.

In the study, researchers exposed a thin “barrier” of four layers of cancer cells to cobalt-chromium ions or particles. Cells close to the nanoparticles experienced signs of mitochondrial damage. But even cells on the other side of the barrier suffered some DNA damage, the team found, despite the fact that there was no evidence that the metals themselves moved through the cells to the other side of the barrier [ScienceNOW Daily News]. Interesting indeed, but experts are pointing out that this set-up is not entirely relevant to humans, or any living organism for that matter.

The nanoparticles used in the study, cobalt-chromium particles, are not used in any medical treatments, but are used in larger pieces to make replacement hips. Hundreds of thousands of people receive cobalt-chromium implants every year, and there has been no evidence of ill effects reported [New Scientist]. Experts also point out that the experiment exposed cells to the nanoparticles at concentrations that were thousands of times higher than what would ever be seen in the body; remember the maxim that “the dose makes the poison.” Finally, the cells used to construct the barrier are human cancer cells (BeWo cells for the jargon-minded) that have been adapted to life in the petri dish, so they aren’t exactly like cells in the body.

Artificial set up or not, if the nanoparticles didn’t cross the barrier, then how was DNA damaged on the other side? The researchers suggested that the nanoparticles created a cascading chemical change. This is the part that is likely to whet the appetites of other scientists in the field. It looks like the nanoparticles set off a series of signals within the cells of the barrier, that ultimately led to the release of DNA-damaging [molecules] through two specific channels at the edge of the barrier [The Great Beyond]. When the researchers then blocked these channels in a subsequent experimentpoof!—the damage didn’t happen.

The researchers who conducted the experiments have responded to the criticism by saying that they only intended to study how the nanoparticles would interact with the physical barrier; they say they didn’t set out to conduct a realistic assessment of potential dangers posed by the particles. Hopefully, other research groups will set out to do just that. Scientists already suspect that nanoparticles can cause damage in some circumstances, and the need for more research is obvious.

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Image: Wikimedia Commons / Nandiyanto

CATEGORIZED UNDER: Feature, Physics & Math, Technology
  • Nick

    I’d like to point out that we already knew that cobalt and chromium were poisonous to humans. They are heavy metals. Tho desirable in trace amounts in our diet (heck cobalt is part of B12) in high enough doses it’s poisonous to humans, whether or not it’s in nanoparticle form.

  • Andrew Maynard

    “Science Smackdown?” Ouch!

    OK, so there’s been some disagreement about the relevance of this paper to human health, and the emphasis on nanoparticles causing harm in some news coverage. But the paper – and the coverage – isn’t entirely without merit. This is what I wrote in response to Bob Service’s piece which you quote above (and which in turn I am quoted in):

    “… I fear that my last quote implies – erroneously – criticism of Nature Nanotechnology for the way media coverage was handled on this paper. The point I was trying to make – and my apologies for bungling it – was that it’s a blurry line between diffusing controversy and creating controversy when handling research results that seem to have socially relevant implications.

    In this case, the paper seemed to have the ingredients of something that could raise concerns – the association of DNA damage with nanoparticles and cellular barriers. Rather than leave coverage to chance, the authors worked with the Science Media Center in the UK to ensure journalists had access to balanced, expert information on the study – in principle minimising the opportunities for uninformed speculation.

    Whether the coverage that followed grasped the subtleties of the work is not clear – certainly, as Bob suggests, there was a tendency to focus on the DNA damage aspects of the study. Yet I do think that, handled differently, the coverage could have been far less informed.

    So back to my point – I do think that in drawing attention to potentially controversial papers there is a danger of fueling the controversy. But that is not an excuse not to actively encourage balanced and science-based coverage, rather than leaving it to chance. It may be dangerous – but sometimes it’s necessary.”

    I provide a more thorough assessment of the paper here: Sure, the paper looks a little flaky if you try and frame it as a warning about the possible dangers of nanoparticles. But as a study of how certain materials interact with certain cells, it has a lot to commend it – which is probably why the peer reviewers at Nature Nanotechnology recommended its publication.

    Either way, suggesting the paper should never have been covered in the news is a dark and dangerous path to take – who then decides what is fit for general consumption, and what should be held back for the intellectual elite? Give me transparency and controversy any day!

  • Thomas Prevenslik

    Science smackdown flies in the face of a decade of experimental evidence that nanoparticles (NPs) damage DNA. One would think that such an article that makes the ludicrous argument if NPs can kill cancer tumors they for some strange thinking cannot cause damage to the DNA – in itself should not have been publsihed.

    With regard to the point of cobalt not causing damage is not relevant because it is cobalt at the nanoscale that causes the EM radiation which damages the DNA.

    I have also commented on the Bristol work elsewhere. See:

    I agree with Andrew Maynard that Bristol work not only should have been published, but needs to be published.

  • Section 8

    Scientist Smack Down? Can anyone say NERD RAGE!?

  • Angie

    I would also be interested in results of experiments with other metals, such as calcium or those our tooth fillings consist of (amalgam). If you were ever forced to take metal supplements in your life, you would realise it does have a negative impact on your health. Therefore I am sure these results are relevant regarding human health. I appreciate the courage of those scientists, who dare to find out more about our lives.

  • Deb

    The statement in the article equating the health effects of large-sized, fixed cobalt-chromium particles with cobalt-chromium nanoparticles indicates that the author either does not understand the toxicity concerns associated with nanoparticles or is purposely trying to muddy the waters by misleading others.

  • Science is my Life

    The article and comment pertaining to nanoqed by Prevenslik, appears to be a cheap gimmick to advertise his own website. Seriously, inherent/sponaneous EM radiations (remember, the scientists at Bristol did not provide any radiation stimulus) from metallic particles causing DNA damage sounds a bit far fetched. His disappointing attempts to link distinct theories to justify his own ideas sounds like an hotch-potch attempt similar to Dan Brown’s DaVinci code. Would Mr Prevenslik then propose that we stop using stainless cutlery as their ‘virations’ or ‘irradiation’ would damage our DNA? His suggestion is a mere insult to Quantum physicists!

    @Deb: Orthopaedic Implants are big metallic objects inserted at a joint. When two metals rub against each other, they can produce wear particles. The properties of a bulk material can be different from the constituent wear/nanoparticles produced and hence their toxicity. The scientists attempt to try and understand this is quite an important task in nanotoxicology and they are not trying to muddy the waters.

  • Thomas Prevenslik

    The comment by “Science is my life” is identical to that in Science Blog to which I have already responded. See:

    What we have here are apologists for the nanoparticle industry that simply want to prolong the time until the US and the European Unions impose regulations on nanoparticles. Muddying waters is not the issue unless there are silver nanoparticles in the mud. The time for trying to understand an important task in nanotoxicology is past. There nowis sufficient experimental data to ban silver nanoparticle in baby food. Forget about muddy water.

  • Deb

    Science is my Life – thanks for the clarification – I better understand the point being made. Too many people out there, scientists included, are still trying to tie assessments of nanomaterial toxicity to bulk materials. Not that the relationship never exists, it’s just that we don’t have enough information to assume it does without evidence.

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