This week’s Sunday Times ran a story headlined “Safety fears over ‘nano’ anti-ageing cosmetics”. The story highlights the company L’Oreal, which, it says, is “marketing a range of skin treatments containing tiny nano- particles, despite concerns about their possible long-term effects on the human body “, and singles out the product Revitalift, which apparently contains “nanosomes” of pro-retinol A. The article quotes both the FDA and the Royal Society on potential unknown health effects, quoting the latter as saying “We don’t know whether these particles are taken down through the skin and what the long-term effects might be in the bloodstream.” There’s an important point that needs clarifying here.
We need to distinguish between manufactured nanoparticles, like the zinc oxide particles mentioned as being used in some sunscreens, and self-assembled nanostructures, like nanosomes, which are the major subject of the article. It’s the manufactured nanoparticles that have given rise to the health anxieties; nanosomes are quite different. Nanosomes are formed from soap like molecules which self-assemble into water into sheets. If you can persuade these sheets to curve round and make a closed surface you have a liposome; a bag in which you can trap useful molecules like the various vitamins and vitamin precursors that companies like L’Oreal like to put in their products (see here for L’Oreal’s own description of this technology). A nanosome is simply a small liposome. The idea is that these molecular delivery bags will both protect the active molecules and help them penetrate the skin. Should we worry that these nanoparticles will enter the human body and lead to long-term adverse effects? Probably not, because the molecules that make up the bag are identical to or very similar to naturally occuring lipids (in fact, the starting point for most liposomes is lecithin, a naturally occurring mixture of phospholipids that’s very commonly used as food emulsifier), and the structures they form are held together by rather weak forces. Liposomes have been much studied as possible drug delivery agents, and this research shows that most liposomes have a rather short life-time in the body. In fact, from the point of view of drug delivery, the lifetimes are rather too short and special tricks are needed – such as the so-called stealth lipsome technology – to prevent the body recognizing and destroying them.
I’m not sure where this piece has come from – it’s written, not by a science correspondent or an environment correspondent, but by the “Social Affairs” editor. I think “Social Affairs” is a rather pretentious categorisation for all those lifestyle pieces that Sunday newspapers are plagued by, and sure enough the “Style” supplement has a consumer review of non-surgical anti-ageing treatments. Perhaps someone in the lifestyle department saw the nano- word, dimly remembered that nanotechnology had been “derided by the Prince of Wales as ‘grey goo’ “, and saw the chance to get a serious story in the paper for a change.
Will the association of these cosmetics with scare stories about the dangers of nanotechnology be bad for their sales? Somehow I doubt it. Given the popularity of botox, it seems that a combination of outrageous expense and the suggestion of danger is exactly what sells an anti-ageing treatment.