Stimulation of Ca(2+) signals in neurons by electrically coupled electrolyte-oxide-semiconductor capacitors

Electrolyte-oxide-semiconductor capacitors (EOSCs) are a class of microtransducers for extracellular electrical stimulation that have been successfully employed to activate voltage-dependent sodium channels at the neuronal soma to generate action potentials in vitro. In the present work, we report on their use to control Ca2+ signalling in cultured mammalian cells, including neurons. Evidence is provided that EOSC stimulation with voltage waveforms in the microsecond or nanosecond range activates two distinct Ca2+ pathways, either by triggering Ca2+ entry through the plasma membrane or its release from intracellular stores. Ca2+ signals were activated in non-neuronal and neuronal cell lines, CHO-K1 and SH-SY5Y. On this basis, stimulation was tailored to rat and bovine neurons to mimic physiological somatic Ca2+ transients evoked by glutamate. Being minimally invasive and easy to use, the new method represents a versatile complement to standard electrophysiology and imaging techniques for the investigation of Ca2+ signalling in dissociated primary neurons and cell lines.