Single cell recordings with pairs of complementary transistors

Floating gate field-effect transistors (FETs) for the detection of extracellular signals from electrogenic cells were fabricated in a complementary metal oxide semiconductor process. Additional passivation layers protected the transistor gates from the electrolyte solution. To compare the signals from n- and p-FETs, two electronically separated, but locally adjacent transistors were combined to one measuring unit. The paired sensing area of this unit had the dimension of a single cell. Simultaneous recordings with n- and p-channel floating gate FETs from a single cell exhibited comparable amplitudes and identical time courses. The experiments indicate that both types of FETs express similar sensitivities.