Electrochemical studies of biocatalytic anode of sulfonated graphene/ferritin/glucose oxidase layer-by-layer biocomposite films for mediated electron transfer

• The electrostatic layer by layer binding of sulfonated graphene SG(−), ferritin Frt(+) and GOx (−).
• Use of biocompatible ferritin as redox mediator.
• Electrocatalytic oxidation of glucose using GC-SG/Frt/GOx bioanode.
• Achieved an electrocatalytic current density of 50 ± 2 mA cm−2 at a scan rate of 100 mV s−1.

In this study, a bioanode was developed by using layer-by-layer (LBL) assembly of sulfonated graphene (SG)/ferritin (Frt)/glucose oxidase (GOx). The SG/Frt biocomposite was used as an electron transfer elevator and mediator, respectively. Glucose oxidase (GOx) from Aspergillus niger was applied as a glucose oxidation biocatalyst. The electrocatalytic oxidation of glucose using GOx modified electrode increases with an increase in the concentration of glucose in the range of 10–50 mM. The electrochemical measurements of the electrode was carried out by using cyclic voltammetry (CV) at different scan rates (20–100 mV s−1) in 30 mM of glucose solution prepared in 0.3 M potassium ferrocyanide (K4Fe(CN)6) and linear sweep voltammetry (LSV). A saturation current density of 50 ± 2 mA cm−2 at a scan rate of 100 mV s−1 for the oxidation of 30 Mm glucose is achieved.