Amperometric Glucose-Sensing Electrodes with the Use of Modified Enzymes

Abstract

Two kinds of modified glucose oxidases (GOD's), a polyethylene glycol-modified GOD and a lipid-modified GOD were prepared and used in the construction of enzyme electrodes. The polymer-modified GOD and a mediator (ferrocene) were incorporated into carbon paste (CP) to prepare a ferrocene-mediated glucose-sensing electrode. The polymer-modified enzyme exhibited higher activity than native enzyme in the CP matrix, owing to the enhanced affinity toward the hydrophobic matrix resulting from the enzyme modification. The higher enzyme activity resulted in an enhanced electrode response to glucose. Another glucose-sensing electrode was prepared by using the water-insoluble, lipid-modified GOD: the modified enzyme was immobilized on the surface of a glassy carbon (GC) electrode with a thin Nafion coating. The lipid-modified GOD-based electrode showed high performance characteristics such as rapid response, high sensitivity and superior stability.