Paper Based Glucose Biosensor Using Graphene Modified with a Conducting Polymer and Gold Nanoparticles

In this work a novel approach was reported for glucose detection using disposable paper based electrodes consisting graphene modified with a conducting polymer, glucose oxidase (GOx) and gold nanoparticles. For the first time, a conducting polymer; poly(9,9-di-(2-ethylhexyl)-fluorenyl-2,7-diyl)-end capped with 2,5-diphenyl-1,2,4-oxadiazole (PFLO) was spread over graphene coated papers and used as a matrix for glucose detection. To finalize the desired biosensor, the enzyme GOx was immobilized with gold nanoparticles (AuNPs) via physical adsorption technique. Oxygen consumption was followed at −0.7 V vs Ag wire in a 50 mM, pH 6.0 phosphate buffer. The amperometric response of the GOx/graphene/PFLO/AuNPs-modified electrode was found to be linearly proportional to the glucose concentration. The fabricated biosensor revealed a high sensitivity for glucose in a linear range from 0.1 to 1.5 mM with a low detection limit of 0.081 mM at a signal-to-noise ratio of 3. K M App , I max , and sensitivity were calculated as 0.229 mM, 2.198 μA, and 7.357 μA/mM cm 2 , respectively. Finally, the constructed disposable biosensor was successfully utilized for the determination of glucose in commercial beverages.