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Ti-MIL-125: A luminescent Metal Organic Framework for the Sensing of Glucose
Cisse, Fatoumata Nancy
Cisse, Fatoumata Nancy
Description
A Master of Science thesis in Biomedical Engineering by Fatoumata Nancy Cisse entitled, “Ti-MIL-125: A luminescent Metal Organic Framework for the Sensing of Glucose”, submitted in June 2024. Thesis advisor is Dr. Rana Sabouni. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).
Abstract
In 2021, approximately 537 million adults globally were reported to have diabetes. This chronic metabolic disease has reached global epidemic level, posing significant health concerns, leading to a rise of interest in the development of glucose-sensing devices. Previously developed glucose sensing systems were unreliable due constant fluctuations caused by their dependence on oxygen and/or the presence of easily degradable enzymes. This has resulted in the creation of enzyme free sensing devices nondependent on oxygen and using nanomaterials. Metal organic frameworks (MOFs) have attracted significant attention for glucose sensing due to their high surface area, low limit of detection, structural diversity, and high sensitivity. While glucose detection by MOFs can be either electrochemical or optical, this thesis specifically focuses on the optical nonenzymatic detection of glucose, where NH₂-MIL-125(Ti) is used as a fluorophore, in the label free detection of glucose, and the intensity of the fluorescence depend on glucose concentration. The sensing capabilities of NH₂-MIL-125(Ti) were assessed through a series of designed experiments aiming to investigate the effect of MOFs dosage, time, pH, and glucose concentration, on the detection performance. The optimal parameters for the experiment were found to be at pH 3.0, 25°C and with a 40 minute wait time. The experimental setup included the determination of the limit of detection. The structural characteristics of MOF were also studied using different characterization tests which confirmed NH₂-MIL-125(Ti) crystallinity, high temperature resistance and ability to trap glucose in its pores. The results also confirmed the stability of Ti-MIL-125 over time making it advantageous in the detection of glucose for diabetic patients. The limit of detection was found to be respectively 43.5 μM for glucose at pH 3.0, 79.8μM at pH 6.0, and 69.2μM for H₂O₂, a by-product in the conversion of glucose to gluconic acid, indicating NH₂-MIL-125(Ti) high sensitivity toward glucose and H₂O₂ and its potential as a glucose sensor in diabetic treatments. Finally, NH₂-MIL-125(Ti) mechanism of detection was found to be a turn on enhancement mechanism with a positive correlation between the fluorescence intensity and glucose concentration.