Preparation of poly(diallyldimethylammonium chloride)-functionalized graphene and its applications for H2O2 and glucose sensing

• PDDA functionalized graphene sheet with well dispersibility and biocompatibility was prepared.
• The PDDA-G/GCE displayed remarkable electrocatalytic activity toward H2O2 reduction.
• Glucose oxidase is stably immobilized via a simple physical adsorption method.
• A biosensor of glucose with an excellent sensing capability is achieved.

In this study, poly(diallyldimethylammonium chloride) (PDDA) was selected as an electron acceptor for functionalizing graphene. The resultant PDDA functionalized graphene (PDDA-G) was characterized using TEM, UV–vis absorption spectrum, Raman spectrum and electrochemical method. The PDDA-G modified electrode displayed remarkable electrocatalytic activity toward H2O2 reduction and can be used as a nonenzymatic biosensor for H2O2 detection. Then negatively charged glucose oxidase (GOD) was immobilized onto the positively charged PDDA-G matrix driven by electrostatic interaction. This novel GOD/PDDA-G bionanocomposite can be used as a biosensor for the detection of glucose with a linear range from 0.02 to 1.8 mM and a detection limit of 8 μM. In this report, the biosensors are easy to prepare, have good stability, and will have potential applications in H2O2 and glucose sensing.

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