Development of electrochemical microsensors for the monitoring of mitochondrial activities

(Pt-Pt-Ag/AgCl) electrochemical microcell arrays were realized using silicon-based microtechnologies. Integrated working platinum ultra-microelectrodes (UME) were characterized compared to standard “polycrystalline platinum” for their electrochemical properties and well-controlled active surface. Nevertheless, further improvements were obtained using a "black platinum" electrodeposition process, allowing to reach a 12-15 fold active surface increase. These modified platinum UME arrays were studied for the detection of hydrogen peroxide (H₂O₂), evidencing a quasi-linear response (sensitivity: ~ 400 pA/μM) and an improved limit of detection (~ 40 nM). Finally, they were applied to the analysis within an oxygraphy chamber of mitochondrial production of H₂O₂. This first study paves the way for the detection of several biomarkers on an integrated microchip and therefore for multi-parametric monitoring of mitochondrial metabolism in physiological and pathological conditions.