WASHINGTON — They promised robots the size of blood cells, able to crawl through the body in search of disease. Featherweight aircraft parts stronger than steel. Solar-charged batteries better and cheaper than oil.
Those and other revolutionary products may yet emerge from nanotechnology, the nascent but quickly maturing field of molecular-scale engineering in which scientists are harnessing the power of the very small.
But for now, it turns out, people will have to settle for odor-eating shoe inserts, livelier golf balls, age-defying nano-nutritional supplements and — for those with a hankering for a really small treat — nanotech chocolate chewing gum.
Such are the products emerging at the intersection of exotic science and prosaic consumerism, as outlined in the first comprehensive inventory of nanoproducts, out today.
The report, compiled by the Project on Emerging Nanotechnologies at the Woodrow Wilson International Center for Scholars, indicates there are more than 200 nanotech-based products on store shelves today — more than double last year's government estimate.
The findings provide fodder for nanotechnology's boosters as well as its critics, with the former applauding the science's emerging economic success and the latter concerned that consumers are being exposed to potentially toxic materials before safety testing and regulatory reviews are complete.
Perhaps most surprising, the list contains several products meant to be eaten — a step up from the kind of exposure that has drawn attention to date, namely nanoparticle-laden cosmetics and sunscreens that some fear could cause harm if absorbed through the skin.
By the Wilson Center's own reckoning, the inventory is conservative. The research and policy group, which is part of the Smithsonian Institution and receives funding from the Pew Charitable Trust, searched the Web in English only for products that manufacturers declared are nano-based. A few were eliminated when it appeared that the prefix was being used more as a sales come-on than as a description of the product's molecular makeup.
Nanomaterials range in size from one to 100 nanometers — a nanometer being a billionth of a meter, or about one-80,000th the thickness of a human hair. Nanoparticles of various kinds are being incorporated in industrial and consumer products because even conventional materials exhibit novel properties when shaved to that size.
Silver, for example, is especially deadly to bacteria in nano form, which is why nanosilver can now be found in refrigerators, vacuum cleaners, shoe sole inserts and other products in need of antimicrobial attention or odor reduction.
Lotions containing nanoparticles of titanium dioxide shield ultraviolet rays but remain glamorously transparent, making them popular as sunscreens.
And nano-based computer chips and hard drives can cram more processing power and data into less space, which is why computers are among the more common places to find nano in the home.
Many products in the inventory (nanotechproject.org) make nano-based performance claims whose accuracy can be difficult to gauge.
Skis that have silicon oxide nanoparticles injected into microscopic voids are said to have greater flex and stability. Nanocapsules in a pain-relief cream supposedly get absorbed through the skin with less irritation. A golf ball with a nanoparticle core promises better response.
Reflecting marketers' natural attraction to already profitable sectors, many nanomanufacturers have focused on cosmetics. The Food and Drug Administration is sponsoring research to see if such products pose any health risks.
At least eight products in the inventory are meant to be eaten, including an Israeli brand of canola oil that contains "nano-sized self-assembled liquids" that are said to reduce cholesterol absorption; about a dozen kinds of nutritional supplements that make various claims of nano-related superiority; and "Choco'la" chocolate chewing gum containing unspecified "nanoscale crystals."
The precise nature of these and other nano-ingredients is unclear from their labels.
The inventory does not include products used in non-consumer applications, including hundreds in use in medical diagnostics and in chemical manufacturing processes.
Preliminary experiments have indicated that some nanomaterials can be toxic, while others have the potential to neutralize poisons and help clean up the environment. Regulatory agencies considering how to classify and handle the new materials have been hampered by companies' general reluctance to reveal details about their products.
The growing variety of nano-based consumer products "is what you'd hope for after a billion-dollar investment in this country," said Vicki Colvin, director of the Center for Biological and Environmental Nanotechnology at Rice University in Houston. But with regulators still not sure what to make of the new science, Colvin said, "these companies have a great responsibility right now to do the safety testing and, to the extent possible, make those findings public."
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