Direct Electrochemical Detection of Glucose on PEDOT Functionalized Screen-Printed Electrodes

This study reports a novel strategy to fabricate a third-generation glucose sensor on screen-printed carbon electrode (SPCE). The direct electron transfer (DET) between glucose oxidase (GOx) and SPCE was accomplished by immobilization of GOx in poly (3, 4-ethylenedioxythiophene) (PEDOT) functionalized electrodes. The use of PEDOT relaxed the requirement for the distance between the redox site of GOx, flavin adenine dinucleotide (FAD) cofactors, and the electrodes in the DET process due to its low ionization potential and good hole-injection ability. This strategy has not required the introduction of an additional mediated agent, and the response current of glucose consisted of DET current. The developed sensor demonstrated high electrochemical responses of glucose in human blood plasma with a wide linear range of 1-14 mM l⁻¹. The reproducibility of the sensor (electrodes) was also studied by sequential determinations of glucose under analogous parameters over time, showing no significant decrease in the faradic response. The construction of DET process with facile methods (3 steps of drop-coating), and simultaneously, the fundamental SPCE does not need any activation process, which makes large mass production of third-generation biosensing systems possible.