The research from the University of Bath about nanoparticles not penetrating the skin has drawn some interest. In addition to the mention here yesterday, in this Oct. 3, 2012 posting, there was this Oct. 2, 2012 posting by Dexter Johnson at the Nanoclast blog on the IEEE [Institute of Electrical and Electronics Engineers] website. I have excerpted the first and last paragraphs of Dexter’s posting as they neatly present the campaign to regulate the use of  nanoparticles in cosmetics and the means by which science progresses, i.e. this study is not definitive,

For at least the last several years, NGO’s like Friends of the Earth (FoE) have been leveraging preliminary studies that indicated that nanoparticles might pass right through our skin to call for a complete moratorium on the use of any nanomaterials in sunscreens and cosmetics.

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This latest UK research certainly won’t put this issue to rest. These experiments will need to be repeated and the results duplicated. That’s how science works. We should not be jumping to any conclusions that this research proves nanoparticles are absolutely safe any more than we should be jumping to the conclusion that they are a risk. Science cuts both ways.

Meanwhile a writer in Australia, Sarah Berry, takes a different approach in her Oct. 4, 2012 article for the Australian newspaper, the  Sydney Morning Herald,

“Breakthrough” claims by cosmetic companies aren’t all they’re cracked up to be, according to a new study.

Nanotechnology — the science of super-small particles — has featured in cosmetic formulations since the late ’80s. Brands claim the technology delivers the “deep-penetrating action” of vitamins and other “active ingredients”.

You may think you know what direction Berry is going to pursue but she swerves,

Dr Gregory Crocetti, a nanotechnology campaigner with Friends of the Earth Australia, was scathing of the study. “To conclude that nanoparticles do not penetrate human skin based on a short-term study using excised pig skin is highly irresponsible,” he said. “This is yet another example of short-term, in-vitro research that doesn’t reflect real-life conditions like skin flexing, and the fact that penetration enhancers are used in most cosmetics. There is an urgent need for more long-term studies that actually reflect realistic conditions.”

Professor Brian Gulson, from Macquarie University in NSW, was was similarly critical. The geochemist’s own study, from 2010 and in conjunction with CSIRO [Australia’s national science agency, the Commonwealth Scientific and Industrial Research Organization], found that small amounts of zinc particles in sunscreen “can pass through the protective layers of skin exposed to the sun in a real-life environment and be detected in blood and urine”.

Of the latest study he said: “Even though they used a sophisticated method of laser scanning confocal microscopy, their results only reinforced earlier studies [and had] no relevance to ‘real life’, especially to cosmetics, because they used polystyrene nanoparticles, and because they used excised (that is, ‘dead’) pig’s skin.”

I missed the fact that this study was an in vitro test, which is always less convincing than in vivo testing. In my Nov. 29, 2011 posting about some research into nano zinc oxide I mentioned in vitro vs. in vivo testing and Brian Gulson’s research,

I was able to access the study and while I’m not an expert by any means I did note that the study was ‘in vitro’, in this case, the cells were on slides when they were being studied. It’s impossible to draw hard and fast conclusions about what will happen in a body (human or otherwise) since there are other systems at work which are not present on a slide.

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… here’s what Brian Gulson had to say about nano zinc oxide concentrations in his work and about a shortcoming in his study (from an Australian Broadcasting Corporation [ABC] Feb. 25, 2010 interviewwith Ashley Hall,

BRIAN GULSON: I guess the critical thing was that we didn’t find large amounts of it getting through the skin. The sunscreens contain 18 to 20 per cent zinc oxide usually and ours was about 20 per zinc. So that’s an awful lot of zinc you’re putting on the skin but we found tiny amounts in the blood of that tracer that we used.

ASHLEY HALL: So is it a significant amount?

BRIAN GULSON: No, no it’s really not.

ASHLEY HALL: But Brian Gulson is warning people who use a lot of sunscreen over an extended period that they could be at risk of having elevated levels of zinc.

BRIAN GULSON: Maybe with young children where you’re applying it seven days a week, it could be an issue but I’m more than happy to continue applying it to my grandchildren.

ASHLEY HALL: This study doesn’t shed any light on the question of whether the nano-particles themselves played a part in the zinc absorption.

BRIAN GULSON: That was the most critical thing. This isotope technique cannot tell whether or not it’s a zinc oxide nano-particle that got through skin or whether it’s just zinc that was dissolved up in contact with the skin and then forms zinc ions or so-called soluble ions. So that’s one major deficiency of our study.

Of course, I have a question about Gulson’s conclusion  that very little of the nano zinc oxide was penetrating the skin based on blood and urine samples taken over the course of the study. Is it possible that after penetrating the skin it was stored in the cells  instead of being eliminated?

It seems it’s not yet time to press the panic button since more research is needed for scientists to refine their understanding of nano zinc oxide and possible health effects from its use.

What I found most interesting in Berry’s article was the advice from the Friends of the Earth,

The contradictory claims about sunscreen can make it hard to know what to do this summer. Friends of the Earth Australia advise people to continue to be sun safe — seeking shade, wearing protective clothing, a hat and sunglasses and using broad spectrum SPF 30+ sunscreen.

This is a huge change in tone for that organization, which until now has been relentless in its anti nanosunscreen stance. Here they advise using a sunscreen and they don’t qualify it as they would usually by saying you should avoid nanosunscreens. I guess after the debacle earlier this year (mentioned in this Feb. 9, 2012 posting titled: Unintended consequences: Australians not using sunscreens to avoid nanoparticles?), they have reconsidered the intensity of their campaign.

For anyone interested in some of the history of the Friends of the Earth’s campaign and the NGO (non governemental organization) which went against the prevailing sentiment against nanosunscreen, I suggest reading Dexter’s posting in full and for those interested in the response from Australian scientists about this latest research, do read Berry’s article.