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

Abstract

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.