Comparative Study of Single-, Few-, and Multi layered Graphene toward Enzyme Conjugation and Electrochemical Response

Graphene, with its exceptional mechanical, thermal, electrical, optical, and electronic properties may exist as single-, few-, or multilayered thin sheets. Though the number of layers may affect conductivity, its role toward enzyme immobilization and enzymatic biosensing applications is unknown. Herein, we report the electrochemical performance of electrodes of graphene comprising varying layers immobilized with the enzyme glucose oxidase for the detection of the model analyte glucose. It is interesting to note that these different-layered graphene exhibit an identical electrochemical performance and sensitivity toward the detection of glucose. In addition, all of these electrodes exhibited a similar percentage of electrode fouling after 60 cycles. Following this, we have then calculated the amount of enzyme bound to the electrode surface. Results indicated that single-, few-, and multilayered graphene electrodes immobilize a similar amount of glucose oxidase. Thus, together, these results demonstrate that the number of layers stacked within the graphene structure have no significant role in the enzyme conjugation and subsequent electrochemical response during the electroanalysis.