The respiratory activity of cultured cells can be electrochemically monitored using scanning electrochemical microscopy (SECM) with high spatial resolution. However, in SECM, the electrode takes a long time to scan, limiting simultaneous measurements with large biological samples such as cell spheroids. Therefore, for rapid electrochemical imaging, a novel strategy is needed. Herein, we report electrochemiluminescence (ECL) imaging of spheroid respiratory activity for the first time using sequential potential steps. L-012, a luminol analog, was used as an ECL luminophore, and H2O2, a sensitizer for ECL of L-012, was generated by the electrochemical reduction of dissolved O2. The ECL imaging visualized spheroid respiratory activity-evidenced by ECL suppression-corresponding to O2 distribution around the spheroids. This method enabled the time-lapse imaging of respiratory activity in multiple spheroids with good spatial resolution comparable to that of SECM. Our work provides a promising high-throughput imaging strategy for elucidating spheroid cellular dynamics.
Keywords: Electrochemiluminescence; Live-cell imaging; Luminol; Mesenchymal stem cell spheroid; Oxygen consumption.
Copyright © 2021 Elsevier B.V. All rights reserved.