Programmed cell death: autophagic cell death. Autophagy (self-eating) is a survival mechanism deployed by cells to cope with conditions of nutrient deprivation. However, unrestrained autophagy can result in genetically programmed cell death. Carbon nanotubes, PAMAMs, and iron oxide nanoparticles were reported to trigger autophagic cell death through the perturbation of the mTOR pathway, while gold nanoparticles may induce autophagy blockade through lysosomal impairment.