Bias-dependent admittance in hybrid bilayer membranes

Artificial bilayer membranes provide a platform for bioelectronic devices based on their structural, sensing, and transport functions. In this letter, we report on the impedance response of an engineered membrane with a lower leaflet of octadecanethiol on gold and an outer leaflet of dioleoylphosphatidylcholine with the monomeric channel protein gramicidin. This hybrid bilayer exhibits an electrical response analogous to a solid-state diode: the admittance is very low (<10 ^-7 Ω ^-1 cm ^-2) over a wide potential range but increases exponentially at negative potentials.