A new dual-function electrical cell stimulation and recording apparatus (ECSARA) for simultaneously electrically stimulating cellular behavior within programmed stand-off electric fields (EFs) and monitoring cellular responses via AC electrical impedance spectroscopy (EIS) is reported. ECSARA is designed to have a footprint similar to that of a common 24-well cell culture plate within which each well is electrified via a pair of opposing planar titanium electrodes, within the cover (0.10 cm2) and base (0.50 cm2) of each well. Porous cell culture inserts established a 3-D milieu for bathing cells while keeping them away from unfavorable fields and forces in the vicinity of the electrodes. ECSARA was tested for its temporal stability, well-to-well variability, and responses in different media. EF modeling showed the field strength to be uniform in the subtending plane of the insert and the magnitude to be influenced by the porosity of the insert membrane. HUVECs were exposed to EF (162 mV/mm at 1.2 Hz) and monitored with standard viability Blue assay and EIS with equivalent circuit modeling. During the first 24 h, the viability (population) of EF-stimulated cells was smaller than non-stimulated control (0.8) but after 72 h they outnumbered the control (1.2) indicating that stimulation initially inhibited growth but resulted in eventual adaptive proliferation. EIS monitoring showed an increase in RCell of EF stimulated and control HUVECs after 54 h and 78 h, respectively. This was in accord with viability data that showed faster growth of EF-stimulated HUVECSs. Confluence was confirmed by VE-cadherin staining. The potential to explore the stimulatory influences of electric fields on cellular processes in tissue and regenerative engineering is now easily possible.
Keywords: EIS; Electric field; Electroculture; HUVECs; Proliferation.
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