New electrochemical sensor based on CoQ10 and cyclodextrin complexes for the detection of oxidative stress initiators

Abstract

The development of coenzyme Q10 (CoQ10) based electrochemical sensor for the detection of oxidative stress initiators is described for the first time. The sensor relies on CoQ10 redox properties. CoQ10 was immobilized at the surface of glassy carbon electrodes (GCE) in combination with cyclodextrins (CD), α-CD or β-CD, that ensure the formation of a well dispersed CoQ10 film. Nanostructured thin films of CoQ10 alone and in complexes with α-CD or β-CD at the electrode surface were characterized by scanning electron microscopy (SEM) and Fourier-transformed infrared spectroscopy (FTIR), enabling to identify the morphology of the films and the interactions between the CoQ10 and CD. Nafion® was used to ensure sensor stability. The optimization of the CoQ10 sensor configuration was made by assessing CoQ10 redox properties through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), correlated with the results obtained from SEM and FTIR characterization. Next, the sensor in the optimized configuration, GCE/α-CD + CoQ10/Nafion®, was applied for the detection of oxidant molecules, hydrogen peroxide and the superoxide radical, through the evaluation of the CoQ10 redox properties monitored by fixed potential chronoamperometry and square wave voltammetry (SWV).