Single step modification of screen printed carbon electrode by composite layer based on polypyrrole, Prussian blue and glucose oxidase

Abstract

Screen printed carbon electrode (SPCE) has been extensively modified to glucose biosensor in order to provide a faster response and accurate measurement for diagnosis purpose such as blood glucose level measurement of diabetes patients. In this project, glucose biosensor was developed in a single step using screen printed carbon electrode with Prussian blue as the redox mediator, polypyrrole as the enzyme immobilization matrix and glucose oxidase as the enzyme. The modification was carried out based on electrodeposition and electropolymerization method by using DropSens μstat 200 at a voltage of 0.6 V for 200 s. Optimization of pyrrole concentration and glucose oxidase concentration was carried out using Design of Experiment, with respective optimum value of 19.01 mM and 261.57 U/mL. The SPCE modified with optimum parameters had a Michaelis-Menten constant of 53.86 mM and high stability of the modified electrode can be maintained for 9 consecutive days. Prussian blue successfully lowered the oxidation potential to 0.01 V hence preventing unwanted potential interferences, and polypyrrole that acted as enzyme immobilization matrix was able to immobilize glucose oxidase onto SPCE while enabling glucose oxidase to carry out its function.