A new glucose sensor based on encapsulated glucose oxidase within organically modified sol-gel glass

A non-mediated glucose biosensor is reported based on encapsulated glucose oxidase (GOD) within the composite sol-gel glass, which is prepared using o ptimum concentrations of 3-aminopropyltriethoxy silane, 2-(3, 4-epoxycycloh exyl)-ethyltrimethoxy silane, GOD dissolved in double distilled water and H Cl. A white, smooth film of sol-gel glass with controlled thickness is also prepared at the surface of a Pt disk electrode without GOD to study the el ectrochemistry of ferrocene monocarboxylic acid at the surface of the modif ied electrode. The electrochemistry of ferrocene monocarboxylic acid at com posite sol-gel glass electrode with varying thickness is reported. The GOD- immobilized film over the Pt disk surface shows a yellow colour. The new so l-gel glass in the absence and the presence of GOD is characterized by scan ning electron microscopy (SEM). The enzyme-immobilized film of different th ickness is made using varying concentrations of soluble sol-gel components applied to the well of the Pt disk electrode. The enzyme is cross-lined wit h the 3-aminopropyltriethoxysilane, one of the composite component of sol-g el glass using glyoxal at 4 degrees C for 4 h. The response of non-mediated enzyme sensor is studied based on cyclic voltammetry and amperometric meas urements. A typical amperometric response of the enzyme sensor having varyi ng thickness of the modified sol-gel glass film is reported. The variation of the response time as a function of the film thickness is reported. The s tability of cross-linked GOD to sol-gel glass is found to be more than a mo nth without loss of enzymatic activity when the enzyme sensor is stored at 4 degrees C. (C) 1999 Elsevier Science S.A. All rights reserved.