Date of Award
Doctor of Philosophy
Importance: Diabetes is a common world-wide disease characterized by insulin resistance and as result there is an increased risk of cardiovascular disease and other metabolic abnormalities, that contribute to irreversible end-organ damage. The cause of diabetes is multifactorial and includes genetic, inflammatory and environmental factors plus lifestyle issues. Because in diabetes there are high levels of glucose and glycated hemoglobin, these molecules are used in clinical settings for the acute and chronic management of diabetic patients.
Objectives: a. To design and build an electrochemical biological sensor using the enzyme Glucose Oxidase (GOX) to detect glucose in biological fluids.
b. To design and build an electrochemical biological sensor using amino-phenyl-boronic acid (APBA) to detect glycated hemoglobin (HbA1c) in blood.
Methodology: The two types of electrodes were built using a similar carbon-coated cellulose matrix followed by a surface pretreatment (Pre-Anodization), and by the addition of cross-linking molecules in order to generate specific covalent bonds. Theses cross-linkers attach to anodized cellulose fibers by specific functional groups as carboxyl’s, generating avid binding sites for either GOX or APBA. The GOX transfers electrons to the matrix through its flavin adenine nucleotide (FAD) subunits as its oxidase’s glucose; the number of electrons transferred is proportional to the glucose concentration in the test solution. Due to the presence of catalase activity in the APBA-HbA1c complexes, and in the presence of H2O2, a proportional number of electrons to the number of bound glycated hemoglobin is transferred to the matrix.
Results: The specific covalent immobilization of GOX and cofactor APBA, was successfully achieved on carbon precoated cellulose matrix. The proposed use of zero-length cross-linkers create the indispensable molecular bindings sites for the functionality of theses disposable paper-carbon electrodes. The GOX-based sensor showed a high sensitivity (60.8723 A. mM-1cm-2) and specificity for the detection of glucose. This APBA-based sensor also showed in laboratory settings high specificity and sensitivity (208.9461 A mM-1cm-2).
Conclusions and Relevance: These new laboratories tested electrodes to detect glucose and HbA1c met FDA requirements and have a great potential to be used as new biosensors for the management of diabetes in clinical settings. Furthermore, these electrodes have the potential for clinical acceptance due to their manufacturing friendliness of portability, high sensitivity, high specificity and low costs.
Received from ProQuest
Henao-Pabon, Gilberto, "A Cellulose-Based Biological Sensor For The Quantitative Determination Of Glucose And Glycated Hemoglobin (HbA1C)" (2020). Open Access Theses & Dissertations. 2981.