Parameter-resolved AC electrical stimulation links electrical system characteristics to early transcriptional...

Alternating-current electrical stimulation (AC-ES) may modulate stem-cell responses, but nominal stimulation settings do not define the electric-field exposure at the cell layer, limiting cross-study comparison. Sinusoidal AC-ES was applied to human adipose-derived stem cells (hASC) and human bone marrow-derived mesenchymal stem cells (hMSC-BM) using a validated in vitro framework that combines continuous electrical monitoring with experimentally parameterized, electrode-electrolyte-interface-informed finite-element simulations. The study was designed to relate physically characterized stimulation conditions to early molecular readouts. Electrical measurements revealed frequency-dependent system behavior, while simulations showed amplitude-dependent shifts in cell-layer exposure across defined electric-field ranges. At 20 Hz and 2 Vrms, where cell-layer exposure shifted from predominantly below 5 Vm^-1 towards the 5-15 Vm^-1 range, osteogenesis- and stress-associated gene expression changed. Higher amplitudes at 20 Hz reduced selected osteogenesis-associated transcripts in hASC, whereas hMSC-BM showed a comparatively stronger osteogenesis-associated response. Markers related to cell death, survival, and proliferation were selectively regulated, while metabolic activity remained comparable with unstimulated controls. Overall, this workflow identifies biologically compatible, parameter-defined AC-ES conditions and supports the rational selection of stimulation settings for subsequent experiments.