A hair dye developed 2,000 years ago relied on nanotechnology to change the graying hair of people in ancient Greece and Rome into a youthful black color, scientists in France report.
Philippe Walter and colleagues studied a hair-dyeing recipe first described in Greco-Roman times, which is the basis of modern hair dyes that gradually darken gray or white hair.
Their research, published in the current (September) issue of the monthly ACS journal Nano Letters, found that the dye works by causing formation of nanocrystals of lead sulfide. That chemical compound forms inside hair shafts and colors hair black without damaging the hair.
The lead sulfide crystals look much like the lead sulfide quantum dots synthesized recently using techniques from materials science, they state.
"In contrast to modern nanotechnology, the dyeing process is characterized by basic chemistry methods and has been developed more than 2,000 years ago with low-cost natural products," the scientists report.
Materials provided by American Chemical Society. Note: Content may be edited for style and length.
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