A new electrochemical aptasensor based on electrocatalytic property of graphene toward ascorbic acid oxidation

Based on the superior electrocatalytic property of graphene (GN) toward ascorbic acid (AA) oxidation, a new electrochemical aptasensor has been developed. Here, adenosine triphosphate (ATP) is used as the model to demonstrate the performance of the developed aptasensor. Briefly, GN is attached to the thiolated ATP binding aptamer (ABA) modified gold electrode through π-π stacking interaction, resulting in a significant oxidation signal of AA. In the presence of ATP, the formation of ATP-ABA complex leads to the release of GN from sensing interface, resulting in a sharp decrease of the oxidation peak current of AA and an obviously positive shift of the related peak potential. Taking both the change values of the peak current and peak potential of AA oxidation as the response signals, ATP can be detected sensitively. This is the first time to demonstrate the application of GN as the nanocatalyst in an amplified aptasensor. It can be expected that GN, as nanocatalyst, should become the very promising amplifying-elements in DNA-based electrochemical biosensors.