A precise flexible printed biosensor based on graphene ink decorated with N-doped graphene quantum dots

Abstract

The improvement of electrochemical properties of graphene compounds can be achieved by using graphene quantum dots (GQDs) due to their high electron mobility, catalytic property and size corresponding to the active site of the enzyme. In this study, we developed a third-generation enzymatic amperometric biosensor based on nitrogen-doped graphene quantum dots (N-GQDs) and printed graphene electrodes (PGE) for the highly sensitive and selective detection of glucose. The PGEs modified with N-GQDs showed a high potential for the precise and sensitive electrochemical detection of glucose. Due to the high electron mobility and electrical conductivity, excellent electrocatalytic activity, large surface area and size compatibility of PGE and N-GQDs with biomolecules, a high sensitivity of 40.76 mA.mM-1.cm-2 and LOD close to 0.098 mM were achieved. The high enzyme surface coverage measured at 3.33 × 10–7 mol.cm-2 further confirmed the excellent enzyme loading capacity and immobilization tendency of the biosensor. Moreover, the N-GQD-based electrochemical biosensors were found to be highly specific and selective even in complex media, especially human blood serum.