Microelectrode Arrays for Electrophysiology of Astrocyte Lineage Cells

Astrocytes, a type of glial cell present in the central nervous system, play a crucial role in brain information processing together with neurons. These cells prominently exhibit Ca2+ excitations and are also characterised by electrophysiological activities that derive from voltage-gated ion channels on their membranes. However, there are few tools specifically optimised to detect their low-amplitude and low-frequency membrane oscillations from the extracellular environment, despite the intrinsic benefits these recordings provide for long-term recording and network studies. In this report, we developed an in vitro 64-channel microelectrode arrays (MEAs). To reduce impedance, our MEAs incorporate a larger electrode size (100 µm in diameter) compared to those designed for neurons and features a coating of PEDOT:PSS on a gold electrode. PEDOT:PSS offers notable biocompatibility and electrical properties. We cultured rat cortical astrocytes on this device and subsequently conducted electrophysiological recordings. The results demonstrated that the device could detect low-amplitude activities in the low-frequency range, which were absent in control recordings both without cells and after cell fixation. Moreover, leveraging the transparency of PEDOT:PSS, we carried out simultaneous recordings of calcium dynamics and electrophysiology in astrocytes and human glioblastoma cells, which are cancer cells that originate from astrocytes. The comparison of results from these two different cell types suggests that the frequency of calcium events in astrocyte lineage cells correlates with the signal intensity of electrophysiological recordings.