Nanoparticles (NPs) are included in a variety of consumer products including cosmetics, food, and food packaging. They are also used in medical products for dermal and oral application and for inhalation. The thinness of the air–blood barrier, the large absorption area of the lung, and the relatively low inactivation by enzymes provide fast entry to the systemic blood circulation at high drug concentrations. In addition to intended uptake, exposure to airborne particles from the environment and to NPs released during the manufacturing process may occur. Cytotoxicity is routinely studied for 4–48 h of exposure, but NPs may accumulate in cells and can cause cellular effects after longer times. Both extent and consequences of cellular NP accumulation are currently largely unknown.
Part of the book: Nanomaterials