Living cells, like HEK 293 o astrocytes can grow on top of an organic semiconductor films. This establishes a photonic interface for communication with the living system that has important application in electrophysiology and neuroscience. Upon polymer photoexcitation, the cell can be excited by modification of the membrane properties. The bio organic interface that is established is a thin cleft of ionic solution separating the polymer film from the cell membrane. Ions in the buffer solution are in chemical equilibrium with charge carriers in the polymer. The whole polymer thickness (few hundred nm) is contaminated by the liquid. A complete characterization of the hybrid solid/liquid interface will be presented , based on optical and electrical techniques. Experiments of cell stimulation by polymer photoexcitation will be described for both astrocytes  and HEK 293 cells. We will show that local photoinduced heating is responsible for HEKL 293 membrane excitation.
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