The aptasensors consisted of a single layer graphene, with the surface of the graphene functionalized using an aptamer that binds specifically to Hg2þ ions. The sensing capability of the aptasensor was demonstrated by real-time responses and showed an unprecedented minimum detectable level (10 pM) and rapid response time of less than 1 second. Moreover, the aptasensor showed outstanding selectivity in mixed solutions containing eight other metal ions. On the basis of the sensing performances of aptasensor, the graphene aptasensor was applied to detect mercury ions in real world samples, leading to the outstanding mercury selectivity from mussels.
In addition, the aptasensor also had excellent mechanical stability and was highly flexible. From these results, liquid-ion gated FET-type graphene-based aptasensor can offer an advanced methodology for state-of-the art mercury analyzing devices and be broadly used for analytical real-sample applications.