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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- A CMOS cantilever platform using adsorption-induced surface stress and piezoresistive transduction for biosensing(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2012-12-01) Rendón Hernández, Adrián Abdalá; Rendón Hernández, Adrían Abdalá; 315444; Martínez Chapa, Sergio Omar; Dieck Assad, Graciano; Camacho León, Sergio; School of Engineering and Information Technologies Graduate Program; Campus MonterreyThis work proposes a biosensing platform based on a microcantilever operating in static mode. The microcantilever transforms the adsorption-induced surface stress into a deflection which is then transformed in an electrical signal by means of a piezoresistive element that is embedded in the structure. A non-destructive and independent-of-fabrication-processes method to characterize residual stress within composite micromachined beams has been proposed. The method was validated by comparing available experimental data and simulation results from fourteen microbeams obtaining an average of 27% absolute error concerning the maximum deflection of the structures. A multipysics model incorporating a suspended beam, a piezoresistor and a Wheatstone bridge has been created in Comsol and used to explore performance of different piezoresistor geometries. A serpentine piezoresistor compared favorably among different geometries and showed a sensibility of 116Ω/µm. Finally, several Bandgap references were designed to be used in conjunction with the Wheatstone bridge in order to get low sensibilities to temperature and voltage supply variations. The best reference showed sensibilities of 18 ppm/ ◦C and 3.2mV/V. This platform was entirely designed to be fabricated in a CMOS process, and is expected to be used in the future to detect and quantify different analytes for environmental monitoring, food industry and biomedicine.
- Desing and Implementation of a CMOS Interface for Non-Invasive Optical Biosensors-Edición Única(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2009-12-01) Eduardo Andrés Barredo Ochoa; Martínez Chapa, Sergio Omar; Dieck Assad, Graciano; Ávila Ortega, Alfonso; Tecnológico de Monterrey, Campus Monterrey; Acevedo Mascarua, JoaquínIn this thesis, I propose an optoelectronic interface as those required in non-invasive micro sensors. The interface was implemented on a 0.35u.m CMOS technology and consists of a photodiode to capture and transform light into a current, and an amplifier to convert this current into a voltage level. I have designed three different photodiodes. Because of their structures, they are called p+/nwell, n+/p-substrate, nwell/p-substrate photodiodes. Additionally, I have implemented the spatially modulated technique in order to increase the photodiodes bandwidth. The required ring to avoid interference and to protect the input pads had also been incorporated in the layout. I have reviewed mathematical approximations that describe the photocurrent in the frequency domain. These approximations could be used in later studies aimed to characterize photodiode. Finally, the amplifier consists on a current to voltage conversion, a bandwidth expansion module and a voltage amplifier. The amplifier has showed a transimpedance of 47 ^/mj[, a frequency bandwidth of 852MHz and a gain-bandwidth of 2GHz.
- Diseño de un Amplificador Operacional CMOS para la Adquisición de Señales de EEG-Edición Única(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2007-08-01) Díaz Torres, Carlos José; Martínez Chapa, Sergio Omar; Dieck Assad, Graciano; Avila Ortega, Alfonso; ITESM-Campus Monterrey; Dieck Assad, GracianoEn esta tesis se presenta el flujo de diseño completo de un circuito integrado, un op amp CMOS para la adquisición de señales de Electroencefalografía. El flujo de diseño empieza con la concepción del diseño, después le siguen los cálculos matemáticos, la captura esquemática, la etapa de simulación, y por ´ultimo el trazado (layout) y verificación. El diseño del op amp es un proceso reiterativo que requiere de muchos ajustes, para poder hacerlo más eficiente y rápido se implementó la metodología del proceso de diseño en una rutina de MATLAB. La etapa de simulación se llevó a cabo utilizando como plataforma experimental el paquete ICFlow de Mentor Graphics R y el HIT-Kit 3.7 de Austriamicrosystems. En la tesis se demuestra la relación directamente proporcional que existe entre las dimensiones de los transistores de la arquitectura electrónica seleccionada y la ganancia de lazo abierto de la misma. El diseño final, cumple con las reglas requeridas para su fabricación siguiendo el proceso de fabricación de 0.35µ de Austriamicrosystems.
- Experimental Research of the Polyamidoamine Dendrimer as a Coating Layer For Microfabricated Silicon Biosensors -Edición Única(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2007-08-01) Quiroga Contreras, José Alberto; Martínez Chapa, Sergio Omar; Valencia Gallegos, Jesús Ángel; Ávila Ortega, Alfonso; ITESM-Campus Monterrey; Dieck Assad, GracianoThis investigation was conducted towards the development of a sensor that can interact in a biological environment to detect a specific biochemical component. The motivation of this research came upon by the need to reduce the periodical bone marrow biopsies that follow treatment on patients with Leukemia; as well reducing the costs associated with the monitoring phase and improving the quality of life of patients. This biosensor could serve as an early-detection device that monitors the concentration of the Angiotensin Converting Enzyme (ACE) inside bone marrow, to send a wireless signal outside the body, indicating a high probability that the patient is entering relapse. In order to develop this type of biosensor, an active biolayer needs to be constructed on top of the sensing mechanism, to be able to “trap” the desired molecule to be detected. The proposed MicroElectroMechanical System (MEMS) to sense the ACE molecule is an array of microcantilevers connected to a microcircuit for data acquisition and analysis, along with radiofrequency transmission capabilities. This work focuses on creating a selective coating material that can interact with a biological medium and sense a specific molecule to measure its concentration. This research started with an exhaustive literature review to target specific problems such as: selecting the MEMS platform, the coupling agent, the coating material, as well as identifying a possible leukemia relapse biochemical indicator. Once the design parameters were established, an experimental phase was conducted. The first step was to functionalize the silicon structure with γ-aminopropyltriethoxysilane (γ-APS). Next, a series of iterative reactions were performed, alternating between a Michael addition and an amidation reaction, using methyl acrylate and ethylenediemine respectively to construct the poly(amidoamine) (PAMAM) dendrimer to be used as the coating layer. At the end of each reaction a sample was taken for analysis with Fourier transform infrared (FTIR) spectroscopy and with an atomic force microscope (AFM). Results show that the PAMAM dendrimer was successfully grown on top of the silicon wafers, but the attachment was not evenly distributed along the surface. A suggested improvement is to perform an oxidizing reaction to the silicon wafer prior to the γ-APS functionalization, in order increase the –OH groups and obtain a uniform attachment of the PAMAM dendrimer on the surface. This thesis concludes with a “future work” section that lays the groundwork to take the next steps in verifying the validity of the model. Among the suggested experiments, the use of ACE antibodies with fluorescent markers is highly recommended to quantify the amount of ACE molecules that are trapped by the PAMAM biolayer with an ACE inhibitor (Captopril) as the molecular sensor.