The purpose of this protocol is to understand the propensity of nanomaterials to induce oxidative stress in the mitochondria. Induction of the oxidative stress is a common toxicity associated with nanoparticles. Generation of reactive oxygen species (ROS) and its control by antioxidant systems is a part of normal cellular metabolism [1]. The total oxidative stress generated in a cell is the result of combined oxidative stress from various organelles such as endoplasmic reticulum, lysosomes, mitochondria, and peroxisomes. Disturbance of redox homeostasis and accumulation of ROS damages cellular organelles and DNA, eventually leading to cell death [2]. Another consequence of excessive ROS generation is activation of stress-related pathways and release of pro-inflammatory cytokines [1]. Depending on the source of ROS, organelle-specific toxicity can also contribute to stress response.