Publicação
Enzymatic electrochemical sensor based on laser-induced graphene (LIG) for glucose monitoring in urine
| Resumo: | Diabetes mellitus (DM), a chronic metabolic disease characterized by elevated glucose levels, affects 9.3% of adults aged 20 to 79 years. An estimated 59.7% increase in global prevalence is expected, making the development of a market for its rapid, accurate, non-invasive, and low-cost detection, indispensable. DM is categorized into type 1 DM (T1DM), type 2 DM (T2DM), and gestational DM (GDM), and its detection and monitoring can be carried out using different methodologies, with this work presenting a comprehensive analysis of these. In addition to the glucometer and urine strip test, research work is also presented, namely enzymatic biosensors, subdivided into three generations, and non-enzymatic biosensors. This thesis aims to present the development and optimization of laser-induced graphene (LIG)-based biosensors for glucose detection, using an electrochemical approach, and the optimization of a second-generation enzymatic biosensor. The LIG synthesis was performed using a laser inscription process on polyimide substrates and was subsequently characterized morphologically by scanning electron microscopy (SEM) and structurally by Raman spectroscopy and energy-dispersive X-ray spectroscopy (EDS). The electrode functionalization step was conducted by incorporating 1 drop of 0.1 M ferrocene, 1 drop of 100 mg/mL glucose oxidase enzyme (GOx), and 1 drop of Aquivion diluted 1:5 (v/v). The biosensor showed excellent performance at 0.4 V, with a sensitivity of 133.11 mA.mM-1.cm-2 and a limit of detection (LOD) of 0.80 mM. Tests were performed on synthetic and real urine, with the presence of the interfering substance uric acid, which demonstrated that the sensor is functional and capable of detecting glucose effectively. However, in the presence of the interfering substance, the sensor trend was followed using anodic currents at 0.25 V and the maximum of the cathodic peak. This thesis contributes to the advancement of the field of glucose biosensors as it offers a promising approach with significant potential in the implementation of rapid response diagnostics and ease of functionalization. |
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| Autores principais: | Roque, Joana Neves |
| Assunto: | Biosensor Glucose Diabetes mellitus Laser-induced graphene Cyclic voltammetry |
| Ano: | 2025 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso embargado |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | Diabetes mellitus (DM), a chronic metabolic disease characterized by elevated glucose levels, affects 9.3% of adults aged 20 to 79 years. An estimated 59.7% increase in global prevalence is expected, making the development of a market for its rapid, accurate, non-invasive, and low-cost detection, indispensable. DM is categorized into type 1 DM (T1DM), type 2 DM (T2DM), and gestational DM (GDM), and its detection and monitoring can be carried out using different methodologies, with this work presenting a comprehensive analysis of these. In addition to the glucometer and urine strip test, research work is also presented, namely enzymatic biosensors, subdivided into three generations, and non-enzymatic biosensors. This thesis aims to present the development and optimization of laser-induced graphene (LIG)-based biosensors for glucose detection, using an electrochemical approach, and the optimization of a second-generation enzymatic biosensor. The LIG synthesis was performed using a laser inscription process on polyimide substrates and was subsequently characterized morphologically by scanning electron microscopy (SEM) and structurally by Raman spectroscopy and energy-dispersive X-ray spectroscopy (EDS). The electrode functionalization step was conducted by incorporating 1 drop of 0.1 M ferrocene, 1 drop of 100 mg/mL glucose oxidase enzyme (GOx), and 1 drop of Aquivion diluted 1:5 (v/v). The biosensor showed excellent performance at 0.4 V, with a sensitivity of 133.11 mA.mM-1.cm-2 and a limit of detection (LOD) of 0.80 mM. Tests were performed on synthetic and real urine, with the presence of the interfering substance uric acid, which demonstrated that the sensor is functional and capable of detecting glucose effectively. However, in the presence of the interfering substance, the sensor trend was followed using anodic currents at 0.25 V and the maximum of the cathodic peak. This thesis contributes to the advancement of the field of glucose biosensors as it offers a promising approach with significant potential in the implementation of rapid response diagnostics and ease of functionalization. |
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