Amine-tethered zeolite dielectric glucose sensing surface for monitoring gestational diabetes

Unlike traditional forms of diabetes, gestational diabetes develops during pregnancy as a result of physiological changes and can lead to significant health complications for both the mother and the fetus. In this study, a chemically tethered zeolite-modified interdigitated electrode (IDE) sensing surface was developed for the quantification of glucose. Zeolite nanoparticles were synthesized from thermal power plant fly ash using a sol-gel method and used for surface functionalization. Imaging of the extracted zeolite with FESEM and FETEM analyses revealed a spherical morphology with a size range of approximately 90 nm. EDX analysis confirmed the presence of major elements [Silica (6.24%), Alumina (5.4%) and Oxygen (48%)] in the synthesized zeolite. Zeolite was immobilized onto the IDE (interdigitated dielectrodes) fabricated by a wet-etching technique, followed by the immobilization of glucose oxidase (GOx) through the aldehyde ends of glutaraldehyde. The chemical surface created can detect glucose as low as 6 mg/dL with a linear regression [y = 0.766x - 0.9727; R² = 0.977], over a range of 6 to 200 mg/dL. Discrimination experiments with uric acid and ascorbic acid did not produce significant current responses, confirming the specificity of glucose detection. Further, glucose mixed with control molecules was detected without interference, indicating a good selectivity.