Chemists, materials scientists and nanoengineers at UC San Diego have created what may be the ultimate natural sunscreen. In a paper published in the American Chemical Society journal ACS Central Science , they report the development of nanoparticles that mimic the behavior of natural melanosomes, melanin-producing cell structures that protect our skin, eyes and other tissues from the harmful effects of ultraviolet radiation. "Basically, we succeeded in making a synthetic version of the nanoparticles that our skin uses to produce and store melanin and demonstrated in experiments in skin cells that they mimic the behavior of natural melanosomes," said Nathan Gianneschi, a professor of chemistry and biochemistry, materials science and engineering and nanoengineering at UC San Diego, who headed the team of researchers. The achievement has practical applications. "Defects in melanin production in humans can cause diseases such as vitiligo and albinism that lack effe...