For example, NIH’s Sally Tinkle has found that under certain conditions–if the skin is stretched a certain way or rubbed with enough force–nanoparticles can move below its top, dead layer. If the skin has cuts and abrasions or has been damaged in some other way, particles can get through to the layers underneath. “That’s well established,” says Tinkle. What happens once these particles reach the bloodstream is unclear. Some studies have found that smaller particles are cleared faster than larger ones and so are safer, but others suggest that once inside the body, nanoparticles travel through the blood, lodge in the lungs and brain, and accumulate over time, with effects that are still poorly understood.
Definitive answers to these toxicity questions may take some time to emerge. But given that nanoparticles behave differently from their larger counterparts, it makes sense to have a regulatory system that is able to recognize this size-dependent behavior. And it makes sense to provide regulatory oversight based on the unique chemistry of nanoparticles.
That kind of oversight might not be welcomed by the cosmetics industry, but without it, the entire promising field of nanotechnology could be in danger. If a safety problem is associated with a cosmetic product marketed for its nano ingredients (even if it doesn’t really have any), the public perception of nanotech could be affected more generally. In Germany, there’s already been one scare with a spurious nano product. In March 2006, after the “Magic Nano” spray bathroom cleaner was released, a number of people who had used it fell ill. Amid the confusion that followed, nobody, including the manufacturers, seemed to know exactly what was in the product. But the damage to nanotech’s reputation had been done. “What it really highlights is the confusion about what people actually mean by the terms,” says Maynard. “We need transparency in this whole area.”
In Bionova’s case, I’m still not sure whether the cream on my dresser contains any nanoparticles, and if it does, whether they will help or hurt me. Since the small dark-blue jar arrived, salespeople from the company have called me four times–ostensibly to check on whether I have any questions. During the first call, the sales rep told me that for the first few days of use, when the cream is opening up my pores and cleaning them out, “your skin is going to look aggravated. It’s going to look itchy; it’s going to look flaky.”
I’ve yet to do more than smell the cream, and I doubt I ever will, so I won’t know whether glowing skin would follow the flakiness, as the salesperson assured me. No matter how lovely the jar is or what lofty promises are made on behalf of its contents, the specter of tiny little nano-whatevers making their way through my body is enough to keep me away.
Apoorva Mandavilli is senior news editor at Nature Medicine.