New Designs of Electrochemical H2O2 Based Biosensors For Advanced Medical Diagnosis

Hydrogen peroxide (H2O2) is an important electroactive species, ubiquitous in biological fluids particularly as cytotoxic agents, generated from the response of antioxidants in enzymatic reactions. It is able to transport across cell membrane and also plays an important role as a second messenger in metabolic mechanisms. Therefore, an ability to quantify the level of H2O2 can be a great tool to assess certain health conditions occurring inside a human body. By a simple approach, an integrated electrochemical biosensor coupled with the hydrogen peroxide quantification can become a practical solution as a point of care device at home, which can be made commercially available worldwide. Not only is it affordable, the biosensor is extremely portable, less than a pocket size. With its own excellent performance, the biosensor is cable of carrying out clinical analysis anywhere; thereby changing the way people with diabetes live their lives. This study aims to strengthen this class of biosensors by promoting a new platform technology into (1) enhancement of catalytic performance by using bimetallic catalysts and (2) extension to a new application for advanced breast cancer diagnosis described as follows:(1)Enhancement of catalytic performance by using bimetallic catalystsMotivated by more improved efficiency in various fuel cell systems, the bimetallic approach has been shown to lead to electrochemical enhancement of platinum catalysts, which in turn are limited by poisoning and slow sluggish anodic reactions. In principle, biosensing systems have analytical behaviors similar to those of fuel cells and could be affected by poisoning and slow oxidation response in the same manner. Thus, incorporating bimetallic Pt catalysts into biosensors may alleviate this problem, thereby enhancing the sensing performance. This research described in Chapter 2 offered an improved design of catalysts based on various second metals: gold (Au), iridium (Ir), nickel (Ni), rhodium (Rh), ruthenium (Ru), and palladium (Pd), adding to the Pt system. Colloidal chemical synthesis route and three-dimensional nanoporous design were used to demonstrate different properties of Pt alloys. The modified electronic and geometric structures of these metal-pairs provided a profound impact for practical implementation and further advancement in detection of future health care technology. (2) Extension to a new application for advanced breast cancer diagnosisAnticipated for a similar process of monitoring blood glucose level for at home management, the research described in Chapter 3 attempts to demonstrate a new approach for breast cancer diagnosis by a potential biomarker, lysyl oxidase like 2 (LOXL2), on the developed electrochemical biosensor. The aberrant LOXL2 expression can be observed in poorly differentiated, high-grade tumors, and, predicted for the acquisition of chemo-resistance, recurrent phenotypes, and overall patient survival in breast cancer. Mechanistically, hydrogen peroxide was produced from the crosslinking activity of LOXL2 through a substrate, lysine, and catalytically oxidized on the developed electrochemical biosensor, capable of detecting LOXL2 in mouse blood, and in human serum and urine specimens of breast cancer patients. The detection method could lead to a minimal invasive detection for breast cancer at home management, potentially minimize an unnecessary chemotherapy treatment for patients.

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

• Janyasupab, Metini

Contributors dc:contributor

• Liu, Chung-Chiun

• Biomedical Research
• Engineering
• Chemical Engineering
• Biosensors
• Bimetallic Catalysts
• Breast Cancer
• H2O2 detection

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=case1364561528

OAI identifier oai:identifier

oai:etd.ohiolink.edu:case1364561528