Graphene quantum dot electrochemiluminescence increase by bio-generated H2O2 and its application in direct biosensing

In this study, a novel signal-increase electrochemiluminescence (ECL) biosensor has been developed for the detection of glucose based on graphene quantum dot/glucose oxidase (GQD/GO x ) on Ti foil. The proposed GQD with excellent ECL ability is synthesized through a green one-step strategy by the electrochemical reduction of graphene oxide quantum dot. Upon the addition of glucose, GO x can catalytically oxidize glucose and the direct electron transfer between the redox centre of GO x and the modified electrode also has been realized, which results in the bio-generated H 2 O 2 for ECL signal increase in GQD and realizes the direct ECL detection of glucose. The signal-increase ECL biosensor enables glucose detection with high sensitivity reaching 5 × 10 −6 mol l −1 in a wide linear range from 5 × 10 −6 to 1.5 × 10 −3 mol l −1 . Additionally, the fabrication process of such GQD-based ECL biosensor is also suitable to other biologically produced H 2 O 2 system, suggesting the possible applications in the sensitive detection of other biologically important targets (e.g. small molecules, protein, DNA and so on).