Electrochemical Response of Glucose Oxidase Adsorbed on Laser-Induced Graphene

Abstract

Carbon-based electrodes have demonstrated great promise as electrochemical transducers in the development of biosensors. More recently, laser-induced graphene (LIG), a graphene derivative, appears as a great candidate due to its superior electron transfer characteristics, high surface area and simplicity in its synthesis. The continuous interest in the development of cost-effective, more stable and reliable biosensors for glucose detection make them the most studied and explored within the academic and industry community. In this work, the electrochemistry of glucose oxidase (GOx) adsorbed on LIG electrodes is studied in detail. In addition to the well-known electroactivity of free flavin adenine dinucleotide (FAD), the cofactor of GOx, at the expected half-wave potential of −0.490 V vs. Ag/AgCl (1 M KCl), a new well-defined redox pair at 0.155 V is observed and shown to be related to LIG/GOx interaction. A systematic study was undertaken in order to understand the origin of this activity, including scan rate and pH dependence, along with glucose detection tests. Two protons and two electrons are involved in this reaction, which is shown to be sensitive to the concentration of glucose, restraining its origin to the electron transfer from FAD in the active site of GOx to the electrode via direct or mediated by quinone derivatives acting as mediators.

A Mediated Enzymatic Electrochemical Sensor Using Paper-Based Laser-Induced Graphene

“…As a comparison, the PaperLIG/GOx/Nafion (0.5%) biosensor was also prepared and measured in the PBS using the amperometric method under −90 mV ( Figure S5a ). Previously, it was reported that graphene material can facilitate the DET (direct electron transfer) of GOx, which might be employed to develop the third generation glucose biosensor [ 52 , 53 , 54 ]. As the co-enzyme of GOx, it was reported that the redox potential for FAD on the LIG electrode is around −485 mV [ 54 ].…”

“…Previously, it was reported that graphene material can facilitate the DET (direct electron transfer) of GOx, which might be employed to develop the third generation glucose biosensor [ 52 , 53 , 54 ]. As the co-enzyme of GOx, it was reported that the redox potential for FAD on the LIG electrode is around −485 mV [ 54 ]. As demonstrated in Figure S5 , no obvious current response could be observed, which indicated that under applied potential (−90 mV) the direct electron transfer from the enzyme to the electrode was not feasible and the usage of a mediator was necessary.…”

Fabrication of Enzyme-Free and Rapid Electrochemical Detection of Glucose Sensor Based on ZnO Rod and Ru Doped Carbon Nitride Modified Gold Transducer

“…From Figure 4 , the highest glucose oxidation peak current is obtained at pH 7.4. In addition, as the PBS solution pH (5 to 8.5) was gradually increased, the glucose oxidation peak potential was positively shifted, which indicates that protons are involved in the electrode processes [ 41 , 42 ]. These results indicate that pH of 7.4 results in higher glucose oxidation current, and it was used for further optimization studies.…”

Deciphering Highly Sensitive Non-Enzymatic Glucose Sensor Based on Nanoscale CuO/PEDOT-MoS2Electrodes in Chronoamperometry

“…39 The values of α of the system electrodes are estimated for the oxidation of glucose. The values of formal standard potential (E 0 / ) are estimated from the yintercept of the linearly fitted line of the peak potential (E p ) vs scan rate (ν) plot 40 (supplied in Fig. S3).…”