Microfluidic integration onto gold microelectrode and its effect on electrochemistry

Integrated microfluidic devices are used in many medical, biological, and other applications due to their characteristics such as small size, sensitivity, reduced amount of needed analyte, ease of use, and accuracy of results. However, it has been noted the results depend on many variables, the most important of which is the electroactive area of the working electrode. In this study, Square Wave Voltammetry (SWV), Cyclic Voltammetry (CV), and Differential Pulse Voltammetry (DPV) have been used for examining four devices with working electrodes with varying electroactive areas altered by changing the size of the integrated channels (50, 100, 250, and 500 µm). The dimensions of the channels are directly related to the surface area of the working electrode. This study aimed to comprehend the changes in electrochemical responses such as macroelectrode-to-microelectrode conversion, limiting currents, the effect of scan rate. Also, Scanning Electron Microscopy (SEM), and Atomic Force Microscopy(AFM) measurements were performed to analyze the nature of the electrode surface in terms of roughness and microstructure. The performance of the electrodes was determined by estimating the working areas for each electrode and conducting electrochemical and microscopic examinations for them. It was observed that when the effective area of the electrode becomes larger, the performance of the electrodes becomes better, and gives more accurate and definite results.