Active intracellular transport of nanoparticles: opportunity or threat?

Active transport mechanisms, relying on motor proteins or polymerization of cytoskeletal filaments, play a central role in the uptake of nanoparticles by cells. While active transport can enhance the effectiveness of nanoparticle therapeutics, it also contributes to the toxicity of nanoparticles released to the environment. In work published in an article in this issue, Galya Orr and colleagues investigated the role of active transport in the interaction of different types of silica particles with alveolar epithelial cells, which are found on the inner surface of the lung.