THE DESIGN OF SENSITIVE, SELECTIVE AND REPRODUCIBLE BIOSENSOR WITH ENZYME IMMOBILISATION FOR ANALYTICAL APPLICATIONS
Manihar Situmorang

Universitas Negeri Medan

Abstract

The design of sensitive, selective and reproducible biosensors with enzyme immobilisation for analytical application is reported. The study is aimed to develop a versatile and accurate analytical tool to be applicable for the determination of target analytes in real samples. The biosensor device is developed with employ immobilised enzyme as catalyic agent to convert target analytes to product that can be monitored electrochemically. Electrochemical biosensors, both in amperometric and potentiometric detection system have been prepared for different types of analytes. The strategy to immobilise ezyme in a matrix polymer is explained. Analytical performances of the the biosensors have been evaluated based on their detection sensitivity, linearity detection range, limit detection, selectivity, and stability. The enzyme electrode is prepared by immobilization of enzyme throughout polytyramine membrane film and attached tightly onto the surface of electrode. The working electrode was made via electropolymerization of monomer tyramine on an electrode surface from a mixed phosphate buffer/methanol solution containing enzyme at pH 6.0 followed by covalent attachment using EDC/NHS crosslinking agents. The precise control over the charge passed during deposition of the polytyramine polymer allows concomitant control over the thickness of the deposited enzyme layers onto the surface of the electrode. The reproducibility of the biosensors achieved is certainly due to the control of the thickness of the enzyme layer being limited by the resistance of the polytyramine film, and to the enzyme immobilization procedure on to the surface of the electrode. The biosensor showed good stability and to be applicable to determine analytes in real samples. Amperometric biosensor has been developed for the determination of various types of analytes such as glucose, sulfite, and uric acid. Potentiometric biosensor has also been developed with the same procedures for determination of analytes such as malic acid, cholesterol, and urea. The biosensor showed good stability and applicable to determine analyte in real samples.

Keywords: Electrochemical biosensor; Reproducible; Enzyme immobilisation; Potentiometric; Amperometric; Polytyramine matrix

Topic: Chemistry