Evaluation of sensitivity of Extended Gate Field Effect Transistor -biosensor based on VO/GOx for glucose detection.

The sensing modified electrode was prepared using glucose oxidase immobilized onto vanadium pentoxide xerogel with glass/FTO as support electrode to evaluate the possibility to construct a VO/GOx Extended Gate Field Effect Transistor biosensor. Previously, our studies exhibited a sensitivity of VO of 58.1 mV/pH. The use of Nafion® onto VO/GOx caused a decrease of mass loss after several cycles compared to the modified electrode without Nafion® during the EQCM and cyclic voltammetrics studies. Electrical characterization of VO/GOx demonstrated a tendency to stability after 200 s as a function of applied current. In presence of glucose and in different pH, the current decreased when the glucose concentration increased due to the lower active sites of enzyme. After ten voltammetric cycles, the total charge tends to structural stability. In pH = 5.0, the modified electrode based on VO/GOx Extended Gate Field Effect Transistor presented more tendency to sensitivity in different concentration of glucose.