Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551039
Pertenecen a esta colección Tesis y Trabajos de grado de las Maestrías correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
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- Application and evaluation of aptamers in the design of the biosensor for the capture of testosterone and/or its synthetic analogs in food supplements.(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2024) Medina Benítez, Ariadna; Antonio Pérez, Aurora; emimmayorquin; Aranda Barrandas, Maria Eugenia; School of Engineering and Sciences; Campus Estado de México; Torres Huerta, Ana LauraThe present project arises from the need to develop a detecting tool for the presence of testosterone and its synthetic analogs in food supplements. Testosterone and its synthetic analogs are part of the androgenic-anabolic steroids (AASs) that are also cataloged as prohibited substances for food supplements since they have several adverse effects. The presence of AASs poses a significant public health issue due to several factors. These include the lack of strict regulations, the rise in consumption of food supplements, and the challenges associated with current analytical methods for assessing supplement composition. In response to this growing problem, the project searches to develop a competitive detection tool with high affinity, real-time detection, and user-friendly operation. To achieve this, the development of a biosensor was proposed, focusing on its two main components: (1) the biorecognition element, utilizing aptamers for their ability to specifically recognize and capture small analytes, and (2) the transducer element, employing gold nanoparticles (AuNPs) for their chemical and optical properties, which enable them to attach to aptamers via thiol modification. For this study, eight aptamers (apT5, P4G13, TESS1, TESS2, TESS3, T4, T5.1, and T6) with previous reports of interaction with testosterone were evaluated to select the best candidate regarding the structural stability at different ionic concentrations and temperatures values, as well as best affinity and interaction characteristics with testosterone, androstenedione, and testosterone undecanoate. In silico analysis allows us to know the stability and behavior of each analyzed aptamer and evaluate the aptamer’s ability to interact with its target. On the other hand, an in vitro analysis tracks the changes in the folded and unfolded aptamer dimensions monitored by the Dynamic Light Scattering (DLS) technique and the structural changes using the Circular Dichroism (CD) technique, both under the previously in silico conditions. An intermediate step was to construct and characterize the size of the biosensing platform (aptamer-AuNPs) and the binding complex (aptamer-AuNPs-analyte) using the DLS technique. To analyze the affinity with the analytes we performed relative capture tests with testosterone and testosterone undecanoate. The results from the in silico approach were consistent with the experimental data gathered, exhibiting that the sequence size in bp, and aptamers native conformation, intervene in their affinity and biosensor functionality. The aptamers apT5, P4G13, and T4 were discarded as possible candidates because they did not show stability and optimal affinity in the in silico analysis. T5.1, and T6 proved to be functional aptamers because they showed good affinity but less stability, both in silico and in vitro, TESS2, and TESS3, showed optimal stability and affinity, however, TESS1 turned out to be the best candidates because of their stability and number of interactions, which translates into a greater affinity, compared to the rest.