Electrochemical Detection of H2O2 for Real-Time Monitoring of Oxidative Stress

Today, the high incidence rate of fatal accidents and occupational diseases in industries is alarming. The use of safety devices and periodic health checks for workers certainly reduce the associated risks, but they are unable to monitor their condition in real-time. In recent years, the research aims to develop electrochemical sensors as an alternative to time-consuming and expensive traditional diagnostic techniques. Moreover, electrochemical sensors are generally flexible and they can be miniaturized, these properties allow their integration into wearable devices. [1] In this work, a low-cost electrochemical sensor was developed to be inserted into a mask for the detection of hydrogen peroxide in the exhaled breath in real-time. So this sensor could avoid the necessity to condensate the exhaled air for its traditional analyses [2]. In particular, hydrogen peroxide is the most used biomarker in monitoring oxidative stress due to its stability and ability to diffuse across the cell membrane. Oxidative stress occurs when the concentration of hydrogen peroxide in biological fluids increases; this condition is a risk factor for many diseases. Since oxidative stress is not associated with specific symptoms, it is important to monitor the concentration of hydrogen peroxide to prevent the onset of serious diseases or slow down their progression. [3] The low cost of this device is related to the fact that it is obtained from CDs at the end of life because their metallic layer, a thin film of silver, can be used for its electrochemical properties. In particular, the silver layer was peeled off the CD and a three electrodes configuration was given using a laser cutter [4]. Then, a graphite paste and an Ag/AgCl paste were applied to the counter and the reference electrode respectively, while the working electrode was modified with a Prussian Blue film in order to improve the electrochemical performance. In addition, a chitosan layer was electrodeposited to facilitate the wettability of the sensor in presence of a humid atmosphere such as that given by exhaled air. Electrochemical tests were carried out in liquid and in aerosol solutions with different concentrations of hydrogen peroxide. The obtained results showed that the current density was proportional to the concentration of hydrogen peroxide, so the sensor can quantify this analyte.