Nanoparticulate materials in antiquity: The good, the bad and the ugly

Combustion products, including soots (black carbon, BC) and multiwall carbon nanotubes have existed in antiquity and soots or BC have been used in inks and paints dating to thousands of years. Other mineral nanoparticles such as TiO2, Fe2O3 and NiO have also found uses in ancient inks and paints as well. Silver or nanosilver has had antibacterial uses spanning several thousand years to the present. But many nanoparticles and nanoparticulate aggregates are toxic to humans or animals and some cause cancers. For example wood soot (complex aggregates of nanospherules of intercalated graphene fragments and PAHs) was identified with scrotum cancer in chimney sweeps in 1775. Chrysotile asbestos, a remarkably multifunctional nanofiber having thousands of uses over nearly 2000 years is toxic and causes mesothelioma and other cancers. TEM and SEM images of these nanoparticulate materials provide a microscopic context for the representative examples.