The holy grail of pyrene-based surface ligands on the sensitivity of graphene-based field effect transistors

Graphene has witnessed intensive research interest due to its remarkabe charge mobility and the efforts in the use of graphene-based field effect transistors (GFET) for sensing of biological biomarkers is on the rise. Because of the high non-specific protein absorption on graphene, well-defined surface modification strategies have to be implemented to benefit from the excellent electronic transfer characteristics of GFET devices for the specific detection of biomarkers. Surprisingly, while pyrene-based ligands are the most widely used graphene surface anchors for sensing-related applications, no systematic investigation on the reaction conditions to be employed and influence of pyrene functionalities have been reported so far. As this is one of the essential step for the efficient receptor integration and sensitive sensing, by using GFET-based analysis of cardiac tropinin I (cTnI) as model compound we will show that an optimized pyrene-maleimide ligands incubation time on graphene of 2h gives the best sensing performance. This study will not only be a guideline for researchers interested in GFET biosensors but will hopefully also allow industrial GFET development in a faster path.