Surface Modification Strategies to Increase the Sensing Length in Electrolyte-Gated Graphene Field-Effect Transistors

Electrolyte-gated graphene-based field-effect transistors (GFETS) are emerging as unique sensing platforms that can offer real-time, cost-effective, and label-free detection of biomolecules with high specificity and selectivity, as well as the in situ monitoring of the dynamics of biorecognition events in real samples. However, operating in biological media still has the challenge of overcoming the screening limitations due to the short Debye length in physiological high-ionic strength conditions. In this regard, many strategies have been developed to extend the sensing length, including the modification of the graphene surface with polymers, lipids, or mesoporous materials. In this chapter, these strategies will be discussed as well as the mechanisms involved in the enhancement of the field-effect sensing signal.