Development and Applications of New Platforms for Electrochemical Sensors
Type of Degreedissertation
Chemistry and Biochemistry
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The primary goal of this dissertation is to develop electrochemical sensors based on novel platforms for applications in medical diagnostics, food safety, and environmental management. Attempts have been made to integrate recognition elements, including biological moecules and synthetic materials, with electrodes through various surface modification strategies, and achieve sensitive, selective, yet low-cost electrochemical sensors for protein quantitation and small molecule detection. Chapter 1 presents a detailed literature review on electrochemical sensors and two types of recognition elements most commonly applied: biological molecules and synthetic materials. Specifically, the properties of aptamers, antibodies, and molecularly imprinted polymers (MIPs), their applications in electrochemical sensing, and the current stage of research are discussed in detail. Furthermore, a brief insight into bipolar electrochemistry and the suitability of employing bipolar electrode in electrochemical analysis is introduced. Chapter 2 presents the development of an electrochemical proximity assay (ECPA). ECPA combines the proximity effect and the electrochemical method for detection of insulin. The detection principle and strategy for obtaining base-line level background are discussed. The model system, first generation of ECPA composed of aptamers, and the system with antibody-oligonucleotide conjugates are illustrated in depth. Chapter 3 describes a MIP-based electrochemical sensor for chiral molecule recognition. The synthesis of MIP particles, characterization, and their incorporation with glassy carbon electrodes by conventional coating method are presented. The results for detection of (+)-catechin and its comparison with results obtained using LC-MS are discussed. Chapter 4 presents a surface imprinting method for fabrication of MIP thin films on electronic transducers. This study employs the self-assembled monolayer technique and unique “click” chemistry for simple, yet efficient surface modification. Detailed fabrication process and applications of sensor in hydroquinone detection are provided. Chapter 5 deals with the development of an electrochemical oxygen sensor based on ECL quenching in a bipolar format. The principles of bipolar electrochemistry, bipolar device fabrication, and ECL quenching are presented. The validation of using ECL quenching as a direct reporter of dissolved O2 concentration is discussed. Chapter 6 summarizes the findings of research. The recommended future work of projects is stated.