Fig. 6
From: Plasmonic imaging of living pancreatic beta-cell networks

Glucose modulation of MIN6 electrical behaviour assessed using MEA recordings. (a) Bright-field micrograph of the circular microelectrode array used for recordings, displaying the radial arrangement of electrodes and the central culture region where MIN6 cells were seeded. Scale bar = 1000 μm. (b) Impedance-based viability maps for three independent wells (W1-W3). Each heatmap shows the impedance magnitude measured at the electrode–cell interface, serving as a surrogate metric for cell coverage and viability. Higher impedance indicates greater cell attachment. The four rows depict: no glucose, 10 mM glucose, 2 μM nifedipine, and two days after nifedipine treatment, illustrating condition-dependent variations in cell viability and adherence. (c) Representative 100-s extracellular voltage traces recorded from the same MEA electrode under three conditions: glucose-free HBSS, HBSS supplemented with 10 mM glucose, and HBSS supplemented with 10 mM glucose plus 2 μM nifedipine. The traces, filtered with a standard 0–15 Hz band-pass, reveal condition-dependent variations in the amplitude of MIN6 electrical activity. (d) Frequency-resolved decomposition of the same electrode shown in (a). Glucose enhances electrical activity, while nifedipine suppresses it within the 1–15 Hz range.