While some visionaries extend the boundaries of human investigation and problem solving, others bring the world that’s already visible into a remarkable, new perspective. Ellen Silbergeld, PhD ’72, does both. An authority on the toxicology of lead and mercury, she is now leading a push to give the blooming field of nanotechnology more critical examination, before it’s too late.
Nanomaterials—often defined as smaller than a tenth of a micrometer in at least one dimension—are being rapidly integrated into everyday life. The large surface area of nanoparticles relative to their volume confers special properties. Nanotechnologies make fabrics stain-resistant, inhibit bacterial growth in food packaging and increase the clarity of cosmetics. They also hold the promise to revolutionize medicine, by penetrating cells and delivering drugs with a precision that was previously impossible.
“I am as capable of being intrigued by nanomaterials as anybody and I think that the promise is potentially very great,” she says. But having witnessed the trajectory of other hyped technologies such as leaded gasoline—which was trumpeted as a 'gift of God' at the time of its introduction and then, once its toxicity became apparent, took decades to remove from the market—Silbergeld, an EHS professor, argues for a more cautious approach, writing articles on the subject and chairing workshops to engage the attention of government as well as fellow scientists. “We’ve just had too much of a history of doing things where the promise was very great.”
Nanotechnologies raise a red flag because the deliberately engineered properties that make them so valuable could make them hazardous. A molecule designed to deliver a drug through a membrane, perhaps administered into the bloodstream, could pick up mercury from the circulation and deliver it instead to intracellular targets like DNA. (Silbergeld describes this as a “sorcerer’s apprentice” problem. The nanotechnology is like the story’s enchanted broom, which continues to draw water from a well even after the room is flooded.)
More careful scrutiny can only be good for nanotechnology in the long term, says Silbergeld, since the belated emergence of hazards would almost certainly undermine the public’s confidence in the technology.
But with an almost total lack of information on the effect of chronic exposure to nanomaterials, a change in course is overdue. “The most important step a responsible society can take is to come to an agreement about the knowledge that’s needed to make decisions about nanotechnology, be it in the private sector in terms of product development, in the public sector in terms of regulation and guidance, or in the public in terms of acceptability,” she says.
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