Amperometric biosensor based on a nanoporous ZrO2 matrix

A biosensor was investigated based on the use of ZrO2 sol-gel matrix for enzyme immobilization in the mild condition. This bioceramic zirconia alcogel has been prepared by the novel alcohothermal route with a cheap inorganic salt Zr(NO3)(4).5H(2)O with several desirable features including a large surface area (about 460 m(2) g(-1)) as well as pore volume and a well-developed textural mesoporosity, and horseradish peroxidase was selected as a model enzyme. The results of transmission electron microscopy (TEM) and BET measurement of the substrate showed that the as-prepared zirconia matrix has an advantageous microenvironment and large surface area available for high enzyme loading. The parameters affecting both the entrapment of enzyme and the biosensor response were optimized. The resulting biosensor exhibited high sensitivity of 111 muA mM(-1) for hydrogen peroxide over a wide range of concentrations from 2.5 x 10(-7) to 1.5 x 10(-4) mol l(-1), quick response of less than 10 s and good stability over 3 months. (C) 2002 Elsevier Science B.V. All rights reserved.