Toward the Ultimate Limit of Analyte Detection, in Graphene-Based Field-Effect Transistors

Abstract

The ultimate sensitivity of field-effect-transistor (FET)-based devices for ionic species detection is of great interest, given that such devices are capable of monitoring single-electron-level modulations. It is shown here, from both theoretical and experimental perspectives, that for such ultimate limits to be approached the thermodynamic as well as kinetic characteristics of the (FET surface)–(linker)–(ion-receptor) ensemble must be considered. The sensitivity was probed in terms of optimal packing of the ensemble, through a minimal charge state/capacitance point of view and atomic force microscopy. Through the fine-tuning of the linker and receptor interaction with the sensing surface, a record limit of detection as well as specificity in the femtomolar range, orders of magnitude better than previously obtained and in excellent accord with prediction, was observed.

Sensitivity-Enhancing Strategies of Graphene Field-Effect Transistor Biosensors for Biomarker Detection

“…For antibody-based GFET biosensors, sensitivity enhancement strategies include modifying the surface morphology of graphene to increase the Debye length, surface functionalization of graphene with multiple antibodies, increasing antibody density, controlling antibody orientation, and enriching target analytes to enhance antibody recognition efficiency. , …”