NANOSTRUCTURING GOLD ELECTRODES FOR GLUCOSE DETECTION VIA ANODIZATION FOR ELECTROCHEMICAL BIOSENSORS

• Autor(a) principal: Sieira, Bárbara de Lima
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/163868
• topic: Nanostructured gold; Anodization; Crystallographic planes; Low potential non-enzymatic glucose sensing; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia dos Materiais

Continuous glucose monitors (CGMs) are indispensable devices for the detection and management of diabetes, a condition that significantly affects the lives of millions of patients. The early identification of diabetes plays a pivotal role in preserving patient well-being and curbing the escalating costs associated with treatment. Traditionally, glucose sensing methods have encountered limitations in terms of precision, sensitivity, and response time due to their reliance on enzymes as receptors. To tackle these challenges, researchers have shifted their focus toward the development of advanced non-enzymatic electrochemical glucose sensors. In this pursuit, the creation and utilization of an efficient electrode emerge as a critical element. Among various materials under consideration, gold electrodes have garnered considerable attention owing to their exceptional conductivity, stability, biocompatibility, and electrocatalytic capabilities for glucose in neutral pH conditions—vital prerequisites for continuous monitoring. Anodization, a controlled electrochemical oxidation process, presents a unique opportunity for tailoring the surface characteristics of gold electrodes. This enables the fine-tuning of sensitivity, selectivity toward glucose, and signal stability in media containing physiological chloride concentrations. By meticulously optimizing anodization parameters like applied potential, electrolyte concentration, and reaction time, one can engineer nanostructured gold surfaces with enhanced attributes. In this study, some differences in crystallographic orientations, morphology, and glucose sensing were detected. It highlights the influence of chloride ions on nanostructured electrodes, underscores the significance of a meticulously optimized cleaning protocol for reliable measurements, and underscores the role of crystallographic planes in sensitivity concerning the electrooxidation potential of glucose. Moreover, the versatility of this technique is showcased as it can be applied to roughened microelectrodes decreasing fourteen times the impedance of the initial value, opening up an expansive research domain. The anodized samples exhibit a good sensitivity ((30 ± 5) A/cm2 ∙ mM) to glucose at lower potentials (0.05 V) compared to unmodified gold electrodes ((41 ± 4) A/cm2 ∙ mM at 0.3 V). This innovation holds substantial promise for the development of energy-efficient, sensitive, and selective electrochemical sensors for glucose detection.