Toxic Nanoparticle Effects (IMAGE) University of California - San Diego Caption These PC12 cells were exposed to no (left), low (center), and high (right) concentrations of iron oxide nanoparticles in the presence of nerve growth factor, which normally stimulates these neuronal cells to form thread-like extensions called neurites. Credit UC San Diego Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.