An electrical method to measure low-frequency collective and synchronized cell activity using extracellular electrodes

TLDR

The authors present an electrical method for measuring extracellular bioelectrical activity in vitro, aiming to capture slow, synchronized cellular events. The method relies on the Helmholtz capacitive double‑layer at the electrode surface, converting μV extracellular voltage fluctuations into a displacement current that is amplified by a capacitance‑dependent gain and further refined by low‑frequency current‑mode operation to suppress electrode noise. The technique was validated on zebrafish hearts and glioma cell cultures, demonstrating its capability to detect low‑frequency, synchronized bioelectrical events.

Abstract

An electrical method to measure extracellular bioelectrical activity in vitro is presented. This method exploits the Helmholtz capacitive double-layer established at the electrode surface. Small extracellular voltage variations in the order of μVs induce through the double-layer capacitor a displacement current that is measured. This current is then enhanced by a gain factor proportional to the electrode capacitance. In addition, when measurements are carried out at low frequencies in current mode the electrode contribution to the noise can be minimized. The performance of the electrodes and the method is demonstrated using zebrafish hearts and glioma cell cultures. We propose that this electrical method is an ideal tool to measure in vitro slow and temporally synchronized events that are often involved in long range intracellular signaling.