New Generation of Electrochemical Sensors for Nitric Oxide;Ruthenium/Carbon-Based Nanostructures and Colloids as Electrocatalytic Platforms

Nitric oxide (NO) is an important intercellular messenger that acts in many tissues to regulate a diverse range of physiological and pathological processes. The physiologically implications of NO function are far from being completely understood. The multifaceted reactivity of NO prompted the need for accurate determination of the concentration of this molecule. However, it is difficult to detect nitric oxide, particularly in biological media and near live cells due to its short half-life, a result of its reactivity and the low levels of NO produced in vivo. As a result, the accurate and reliable detection of NO under varying experimental conditions has always posed a challenging task. The main goal was to develop ultra-sensitive electrocatalytic sensors for accurate quantification of NO. We report the fabrication and characterization of improved NO sensors based on electrocatalytic platforms such as ruthenium (colloids, nanoparticles, and nanotubes) and carbon (pastes and nanotubes), acting as catalytic sites for NO oxidation. These sensors are characterized using various surface analytical tools. The electrocatalytic oxidation of NO is assessed by cyclic voltammetry and amperometry both in solution phase and gas phase. Excellent sensitivity and linearity are observed for our modified electrodes towards NO quantification. Our new NO detection sensors also show superior limit of detection and selectivity against common interference species. Our NO sensors are tested for various applications including in the measurement of NO released from human umbilical vein endothelial cells (HUVECs