Microfluidic devices for cell culturing and electrochemical sensing of hydrogen peroxide and nitrite

Integration of electrochemical detection (ED) in cell culture is an advantageous strategy to detect the secretions from cultured cells. This is especially interesting for unstable species since they are not diluted prior to detection, so the minute quantities of species secreted be detected and quantified. Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) are a group of compounds of special interest because of their critical role in physiological processes like cellular signalling and immunological activity. However, an overproduction may cause the so-called oxidative stress (OS) which is able to cause damage to lipids, proteins or DNA. These alterations promote pathophysiological conditions such as diabetes, cancer, Alzheimer’s and Parkinson’s disease. To study this phenomenon, hydrogen peroxide (H2O2) and nitrite (NO2-) were selected as indicators of ROS and RNS respectively for their stability and for being the stable end-products for each group. In this work, the ED of these compounds has been studied employing different electrode materials like Pt, carbon black (CB) and Prussian Blue. The microfluidic system coupled with ED was further employed to culture different cell lines and to follow their response in terms of H2O2 and NO2- concentrations released after treatment with LPS and Zymosan A.