Reactive oxygen species (ROS) are natural byproducts of the normal metabolism of oxygen and play important roles in cell signaling. However, during oxidative stress-related states, ROS levels can increase dramatically. The accumulation of ROS results in significant damage to cell structures. The role of oxidative stress in cardiovascular disease, diabetes, osteoporosis, stroke, inflammatory diseases, a number of neurodegenerative diseases and cancer has been well established. The ROS measurement will help to determine how oxidative stress modulates varied intracellular pathways. Amplite™ Fluorimetric ROS Assay Kit uses our unique ROS sensor to quantify ROS in live cells. Amplite™ ROS Red is cell-permeable. It generates the red fluorescence when it reacts with ROS. The kit is an optimized “mix and read” assay format. The Amplite™ Fluorimetric ROS Assay Kit provides a sensitive, one-step fluorimetric assay to detect intracellular ROS in live cells with 1-2 hours incubation. The assay can be performed in a convenient 96-well or 384-well microtiter-plate format and easily adapted to automation without a separation step. Its signal can be easily read using either a fluorescence microplate reader or a fluorescent microscope at Ex/Em = 520/605 nm. It can be used to either quantify the ROS activities or screen the ROS inhibitors.