Development of Electrochemical Biosensors for Potential Liver Disease Detections of ALT & AST and Application of Ionic Liquid into Biosensing-Modified Electrodes

This study focused on the biosensing detection of the biomarkers relevant to liver diseases: alanine aminotransferase (ALT) and aspartate aminotransferase (AST). The proposed biosensor technology provided a useful tool for potential clinical-screening of liver status.Iridium (Ir) nanoparticles possessed excellent electrocatalytic activity and its incorporation into the biosensor provided excellent detection of H2O2 oxidation which was oxidized at a low applied potential (+0.27 V versus the printed Ag/AgCl electrode). The biosensing detection of ALT or AST individually was achieved using the proposed iridium-carbon (Ir-C) biosensor based on the electrochemical measurement of the enzymatically-liberated H2O2. Serum-aminotransferase detection of ALT or AST was accomplished in a few minute. Therefore, any additional mediator or anti-interference membrane was not required.ALT and AST coexisted in a human blood. A glutamate biosensor with glutamate oxidase (GluOx) immobilization was desirable to the quantifications of both aminotransferase activities sequentially using a single biosensor design. The kinetic-controlled measurement was undertaken. In this approach, AST was measured accurately and ALT was detected only qualitatively.In another study, an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate [BMIM-BF4]) was employed to modify the electrode in this biosensor system. A PyOx/Chi-IL/Ir-C biosensor was developed immobilizing pyruvate oxidase (PyOx) into a modified matrix of chitosan (Chi)–ionic liquid (IL). A sensitive and selective detection on serum-ALT was performed. Incorporating BMIM-BF4 into the Chi-matrix yielded a benign environment and retained most activity of immobilized PyOx based on UV-vis adsorption characterizations. The synergistic efforts of Chi-IL matrix into Ir-C biosensor prolonged the shelf life of the PyOx/Chi-IL/Ir-C biosensor.A glucose Ir-C biosensor was developed immobilizing glucose oxidase (GOx) with various quantities of IL (BMIM-BF4), onto the glutaraldehyde (GA)-crosslinking chitosan (Chi) matrix. The effect of IL was investigated based on electrochemical and spectrophotometric performance of the glucose sensor. Oxygen effect on this IL modified electrode for glucose detection appeared to be negligible, using the reduction mode of H2O2 measurement. This glucose biosensor showed improved and attractive features on high sensitivity, high biological affinity (low KM), and long-time storage life.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Chemical Engineering

Grantor dc:publisher

Case Western Reserve University School of Graduate Studies

Year dc:date

2013

Author dc:creator

• Hsueh, Chang-Jung

Contributors dc:contributor

• Liu, Chung-Chiun

• Chemical Engineering
• Biomedical Research
• Materials Science
• Polymer Chemistry
• Electrochemical biosensor
• thick-film screen printing
• iridium nanoparticle
• aminotransferase
• chitosan
• ionic liquid

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=case1364989187

OAI identifier oai:identifier

oai:etd.ohiolink.edu:case1364989187