Real-time monitoring of insulin using a graphene aptameric nanosensor

We present a new approach for real-time, specific and sensitive detection of insulin using a graphene aptameric nanosensor. The nanosensor is configured as a graphene field effect transistor, where the graphene conducting channel was functionalized with a guanine-rich aptamer IGA3 that would form an anti-parallel G-quadruplex upon insulin binding. The aptamer conformational changes altered the electrical conductance of graphene by varying the carrier density of the graphene. The nanosensor allowed us to perform real-time, label-free and specific detection of insulin concentrations as low as 1 nM.