Effect of self-assembled monolayers (SAMs) in binding glucose oxidase for electro-enzymatic glucose sensor with gold electrodes

In this paper, a new approach to improve long term stability of electro-enzymatic glucose sensors is presented. Self-assembled monolayers (SAMs) are employed for surface treatment of the gold electrodes to improve adhesion. Three types of functional alkylthiols, namely 11-amino-1-undecanethiol hydrochloride, 1-hexadecanethiol (1- hexadecanthiol) and 1,9-nonanedithiol, and bovine serum albumin (BSA) are investigated in our study. Alkylhiols are used for surface treatment of gold electrodes and BSA is mixed in enzyme (glucose oxidase) solution to realize the proposed sensors. Furthermore, gold is investigated as an electrode material. Both reference and active electrodes are fabricated using only gold. The current response of the modified sensors showed long term stability. However, the unmodified sensors showed very short term stability because glucose oxidase does not adhere well to the electrodes. The proposed modified sensors also show lower drift than the unmodified sensors without surface treatment and BSA.