Amperometric detection of glucose with glucose oxidase immobilized in layered double hydroxides

A novel cheap and simple amperometric biosensor, based on the immobilization of glucose oxidase (GOD) into anionic clay; layered double hydroxides (LDHs) [Zn-3-AL-Cl] is presented. GOD can be entrapped in the LDHs gel via electrostatic interaction. Amperometric detection of glucose with an unmediated sensor at 0.6 V (vs. SCE) results in a rapid response (5 s), a wide linear range of 0.001-12 mM, as well as good operational stability. The low detection limit was 0.1 mu M at 3 sigma. The apparent Michaelis-Menten constant (K-M(app)) is 4.4 mM. The general interferences that coexisted in blood serum do not affect glucose determination, except for uric acid. In addition, optimization of the biosensor construction and the effects of the applied potential on the amperometric response of the sensor were investigated and discussed herein.