Fast Voltage Transients in Capacitive Silicon-to-Cell Stimulation Detected with a Luminescent Molecular Electronic Probe

The capacitive stimulation of nerve cells from semiconductor chips is a prerequisite for the development of neuroelectronic devices. We report on the primary response of a cell membrane to a voltage step applied to oxidized silicon. It is observed with a luminescent voltage-sensitive dye. We find exponential voltage transients with a time constant of $1–5\mu \mathrm{s}$. We assign the short response to an electrical decoupling by a thin film of electrolyte between oxide and membrane. The high-pass filtering of stimulation is a crucial constraint for the development of silicon-to-neuron interfaces.