With the increasing evidence of the involvement of oxidative stress in many diseases, interest in developing methods that can measure oxidative stress biomarkers in real time has continuously increased. Electrochemical methods and sensors are ideally suited for monitoring ROS and RNS with very high sensitivity and real-time resolution, crucial for quantifying these short-lived reactive species (RS) in situ. This chapter describes the development status of electrochemical methods, sensors, and biosensors for in vivo/in vitro monitoring of ROS/RNS and provides examples of measurement capabilities in pathophysiological conditions associated with oxidative stress for disease monitoring, pharmacological screening, and other relevant biomedical applications. Recently reported microelectrode designs and methodologies based on chemical and enzyme-based approaches as well as their advantages and limitations are discussed. Examples of possible imple-mentation and translation of this technology to evaluate oxidative stress in cellular, tissues, and whole animal models are also provided to demonstrate potential of this technology in biology and biomedical fields.
