An electrochemiluminescence aptasensing platform based on ferrocene-graphene nanosheets for simple and rapid detection of thrombin

• The biosensor takes advantage of the effective quenching pattern of ferrocene (Fc) to Ru(bpy)32+ via unique π–π interaction between nucleotides and ferrocene-graphene nanosheets (Fc-GNs).
• Fc-GNs not only shows an effective quenching to Ru(bpy)32+, but also provides a platform for the immobilization of Ru(bpy)32+ tagged thrombin binding aptamer (Ru-TBA) and simplifies the experimental design.
• The proposed method could be widely applied to the aptamer-based determination of a spectrum of targets with different types of aptamers to recognize their respective target molecules.

In this work, we tactfully constructed an electrochemiluminescence (ECL) aptasensing platform with ferrocene-graphene nanosheets (Fc-GNs) using the ferrocene (Fc) as quench unit to tris(2.2′-bipyridyl) ruthenium (II) [Ru(bpy)32+] and the Ru(bpy)32+ tagged thrombin binding aptamer (Ru-TBA) to recognize the thrombin molecules. Duing to the unique π-π interaction between nucleotides and graphene, the Ru-TBA could be preferentially adsorbed on the surface of ferrocene-graphene nanosheets with the signal generator into off-state. The conformational transformation of Ru-TBA leads to the desorption of Ru-TBA from Fc-GNs after the biosensing electrode incubating with the thrombin solution and the ECL “signal-on” was triggered. With the transformation of luminescence signal from “off” to “on”, the biosensor exhibited high sensitivity for the determination of thrombin with a detection limit of 0.21 nM. Particularly, the proposed method could be widely applied to the aptamer-based determination of other target analytes.

Schematic illustration of the ECL biosensor for thrombin detection.Figure optionsDownload as PowerPoint slide