Femtomolar detection of Cu2+ ions in solution using super-Nernstian FET-sensor with a lipid monolayer as top-gate dielectric

[Display omitted] •A new Di-picolylamine-lipid sensitive layer for the detection of Cu2+ in solution.•Lowest limit of detection (10 fM) reported for small ions in solution.•First FET sensor using a lipid monolayer as ultra-thin top-gate dielectric showing a super-nernstian behavior.•Very high stability of sensor over measurements due to lipid layer blockage to ions trapping. The development of ions sensors with low limit of detection and high sensitivity and selectivity is required in many fields of application and still remains a challenge. We report on the first dual-gated field effect transistor sensor with an engineered lipid monolayer as top gate dielectric. The sensor was designed and fabricated for the specific detection of Cu2+ using the Di-2-picolylamine as recognition unit. The lipid monolayer was reticulated to achieve high mechanical and dielectric stability over device operation. The resulting sensor exhibits exceptional performances with a limit of detection at 10 femtomolar, with a linear dependency over 10 decades and a super-Nernstian sensitivity of ∼100 mV/decade. We also show that the lipid layer forms a good barrier to ions trapping, hence providing a high stability of the sensor over measurements.