Electrochemical imaging using redox mediators for cell activity of three-dimensional cultured cells

摘要

Three-dimensional (3D) cultured cells are widely used for tissue engineering and drug screening. Therefore, a methodfor evaluating them is desired. Several kinds of tools have been developed. Among them, electrochemical approaches arereceiving considerable attention because of their great features, such as simplicity and highly sensitive detection.Especially, electrode array devices have been developed for electrochemical imaging of cell activity. In heelectrochemical imaging, cell activity is converted to current values at electrochemical sensors, and we obtain 2D imagesconsisting of the currents, which is called as electrochemical images. The electrochemical images are useful for chemicalmapping. We previously reported a CMOS-based amperometric device containing 400 sensors for electrochemicalimaging. The device was applied for electrochemical imaging of several kinds of cell activity. In this study, the devicewas applied for evaluating intracellular activity using redox mediators. To access intracellular compounds, hydrophobicmediators were used because the mediators can penetrate cell membranes. First, ferrocenemethanol (FMA) was used as ahydrophobic mediator and oxidation currents of FMA were measured. However, the detection was unsuitable forevaluating intracellular enzymes and/or redox compounds. Next, a double-mediator system of [Fe(CN)_6]~(3-) andmenadione was adapted for measuring intracellular sensing. The detection is deeply discussed in the oral presentation.Briefly, quinone oxidoreductase 1 (NQO1) activity was successfully detected. In the future, the detection system will beused for drug screening.