Neuron adhesion on a silicon chip probed by an array of field-effect transistors

The interaction of an individual nerve cell with a surface of oxidized silicon is studied. ac voltages from 0.1 to 5000 Hz are applied to the neuron. The resulting voltage profiles in the cleft between cell membrane and surface are recorded by an array of sixteen field-effect transistors with open metal-free gate oxide. Using methods of the cable theory to describe the contact area (diameter around 35 mu m), we evaluate the width of the cleft (around 20 nm) and the conductance of the membrane, which is enhanced by an order of magnitude.