Author: Cao, Jinglin
Title: Glucose microsensor based on GOD/Chitosan/PEGDA-modified interdigital microelectrode
Advisors: Zhang, A. Ping (EE)
Degree: M.Sc.
Year: 2020
Subject: Electrochemical sensor
Transducers, Biomedical
Blood glucose monitoring
Hong Kong Polytechnic University -- Dissertations
Department: Department of Electrical Engineering
Pages: xi, 68 pages : color illustrations
Language: English
Abstract: Diabetes is a frequently occurring and common disease worldwide, and the third most common disease after cardiovascular and cancer. In recent years, there has been an endless stream of glucose testing techniques and methods. Among these methods, glucose electrochemical sensors, which have the advantage of high selectivity, high sensitivity, and can be rapid response, have attracted a lot of attention.
Electrochemical enzyme biosensor is a sensor that combines electrochemical analysis methods with enzyme biotechnology. It not only has the specific catalytic properties of enzymes, but also has the advantages of sensitivity, rapidity, and easy operation of electrochemical sensors. The glucose electrochemical sensor uses glucose oxidase (GOD) to immobilize on the surface of the electrode as the identification element, and detect the glucose concentration by measuring the electrical signal.
In this thesis, a novel glucose sensor with hydrogels as the carrier of GOD has been successfully fabricated. The hydrogels are combined with GOD, chitosan and poly(ethylene glycol) diacrylate (PEGDA). In order to improve the signal-to-noise ratio of detection, the whole sensor is made into micro interdigital electrode. The sensing area of this sensor is around 0.54mm2, and the minimum electrode width is designed to be 11.5 micrometers. To reduce the potential of enzyme reaction and reduce the influence of oxygen, Prussian blue (PB) is selected to be the electron mediator. Cysteamine (CYS) modified gold surface is used as electrode substrate, to enhance the curing ability of the hydrogel on the gold electrode.
The test results show that the glucose sensor can produce different response signals to different concentrations of glucose, and the signal result is basically linear. Further analysis about this sensor shows that the detection range is 0.06-15.3mmol/L, sensitivity is 3.485μA mM−1 cm−2, with the response time is 40s. Further experiments show that the electrode width and gap of the interdigital electrode have an effect on the signal response and intensity, the smaller the electrode width, the higher the signal strength.
Rights: All rights reserved
Access: restricted access

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