Fast Voltage Transients in Capacitive Silicon-to-Cell Stimulation
detected with a Luminescent Molecular Electronic Probe
Dieter Braun and Peter Fromherz
Physical Review Letters 86 (2001) 2905-2908
Abstract
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 µs. We assign
the short response to an electrical decoupling by a thin film
of electrolyte between oxide and membrane. The highpass filtering
of stimulation is a crucial constraint for the development of
silicon-to-neuron interfaces.
Fig. 2: Fluorescence and electrical response of
HEK293 cell stained with the dye BNBIQ. (a) Fluorescence
intensity. The circles mark two areas of the attached
membrane (JM) and of the free membrane (FM).
(b) Map of time constants t_J of the optical transients
after a positive voltage step applied to silicon. Red codes
for positive voltage transients across the membrane
(negative optical transients), blue for negative voltage
transients (positive optical transients).
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