Nanoparticles present in cosmetics, sunscreens, and other personal care products may be harmful to the environment, according to new research presented at the 237th National Meeting of the American Chemical Society.

Ohio scientists Cyndee Gruden, Ph.D., and Olga Mileyeva-Biebesheimer analyzed nano-titanium dioxide (nano-TiO2) particles that are added to products for their ability to block ultraviolet light in sunlight. Excess exposure can fuel premature aging of the skin, as well as  cause skin cancer.

Gruden, who works at the University of Toledo, said that while people bathe, particles are washed down the drain in homes and make their way toward municipal sewage treatment plants. Once there, they can enter lakes, rivers, and other water sources.

Examining the survival of Escherichia coli (E. coli) bacteria when exposed in laboratory cultures to various amounts of nano-TiO2, Gruden discovered large reductions in survival in samples exposed to small concentrations of the nanoparticles for less than an hour.

Gruden’s located damage from nanoparticles using fluorescence to identify the point at which the cell membrane in microbes undergoes damage. Once membranes are damaged, cells emit a faint red glow. Fluorescence allow scientists to obtain results faster, and perhaps with greater sensitivity, Gruden said, adding that the technique could facilitate scientific efforts to understand the threshold at which nanoparticles become toxic to microbes.

Researchers will now look ahead to perform studies that determine whether the same effects occur in the natural environment.

[Source: Medical News Today]