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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- Simulation of a centrifugal microfluidic device for particle separation through acoustophoresis(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2021-08-02) Rubio Téllez, Montserrat; MARTINEZ CHAPA, SERGIO OMAR; 31803; Martínez Chapa, Sergio Omar; emipsanchez; Ray, Mallar; School of Engineering and Sciences; Campus Monterrey; Madadelahi, MasoudParticle and cell separation is a fundamental operation in biomedical research and clinical diagnostics. Circulating tumor cells (CTCs) separation is gaining interest because its detection and further study can help in early cancer diagnosis or provide guidance in chemotherapy treatment. Acoustophoresis in microfluidic devices has the potential to separate CTCs and rare cells from blood samples. This technology manipulates particles with acoustic waves and is a contact-free, label-free and highly sensitive technique. There has not been any experimental or computational study integrating acoustophoresis in centrifugal microfluidic platforms. This work presents the proof of concept of both principles for particle and cell separation, through the simulation of the device. A 3D FEM-based model was built in COMSOL for predicting the particles path. The geometry consisted first in a Surface Acoustic Wave based device with 2 pairs of IDTs located on top of a piezoelectric substrate, with a rectangular fluid channel with three inlets and three outlets. By applying boundary conditions, input parameters, and considering centrifugal, Coriolis, drag, lift and acoustic radiation forces; the particle’s paths are obtained. An attempt to validate the model with a previous experimental work was not successful since the acoustic pressure field was not generated correctly. However, the model was validated with a previous published simulation work of a non-centrifugal platform, and then used for computational demonstration of acoustophoretic separation of CTCs from white blood cells and red blood cells. A parametric analysis was performed to study the influence of five parameters on the efficiency of the device. Results showed that the recovery rate of CTCs at the center-outlet decreases when the angular velocity increases, when the distance to the axis of rotation increases, and when the distance between the IDTs and the channel increases. Recovery rate of CTCs at the center-outlet increases when voltage increases. Centrifugal platforms were found to be more sensitive to density variations. The model was modified to simulate a Bulk Acoustic Wave-based device and an attempt to validate it with a previous experimental work was done, however limitations were found. This work provides an understanding of the behavior of a centrifugal microfluidic platform with acoustophoresis and might be used as the initial reference for future computational work for correctly generating the acoustic pressure field and subsequently future experimental studies of particle and cell separation.
- Experimental and computational study of GelMA microgel generation and deformation using a microfluidic device(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2020-12-01) Taravatfard, Zahra; Martínez Chapa, Sergio Omar; qro /|bqrotbecerra/tolmquevedo; Ray, Mallar; School of Engineering and Sciences; Campus Monterrey; Madadelahi, MasoudGene editing is a technique through which DNA segments can be modified within the genome of a living organism. Despite the many potential applications, current gene editing techniques are still low-throughput and have several limitations. On one side, the conventional 2D cell culturing techniques suffer from low cell viability and proliferation. On the other side, transfection techniques commonly using exogenous materials lead to off-target effects in cells. Droplet-based microfluidic devices (DBMD) show great potential for gene editing. They allow precise single-cell manipulation, encapsulation and might eventually achieve high throughput. As an example, using a DBMD, cells encapsulated in GelMA microgels have kept viability and shown proliferation. Moreover, DBMD might play a key role in cell transfection. Particularly, mechanical squeeze of cells encapsulated in droplets and moving through a narrow channel favors the entrance of foreign materials into the cells. This thesis presents the design and implementation of droplet-based microfluidic systems for fabrication of monodisperse GelMA microgels. First, a DBMD was developed using three techniques of soft lithography, stereolithography, and cutter plotting and the comparison between the devices was conducted. Second, fabrication of both, solid-like as well as core-shell microgels with average size of 133.43±5 µm was demonstrated. It was shown the generated microgels have spherical morphology with pore size area of 23.28±6 um2. Finally, computer simulation was used to emulate microgel indentation (solid-like and core-shell) with or without cells; as well as the throughput of the designed confinement channel. From the indentation of particles, it was concluded that lower stiffnesses was obtained for core-shells in comparison to solid-like microgels. It is also shown that a 21% and 24 % deformation in microgels containing cells causes 30% and 40% deformation of encapsulated cells, respectively, vital in cells transfection-based confinement channel application. From computational fluid dynamics (CFD) model, we observed the enhancement of the throughput of the device by selecting a longer confinement length. It is expected these preliminary results presented in this thesis will motivate other works that eventually lead to the development of efficient droplet-based microfluidic devices for cell transfection.
- 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.
- Diseño de microespejo CMOS de barrido resonante para sistemas endoscópicos de tomografía óptica(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2006-05-01) Camacho León, Sergio; CAMACHO LEON, SERGIO; 213140; Martínez Chapa, Sergio Omar; Elías Zúñiga, Alex; Gutiérrez Vega, Julio César; Programa de Graduados en Tecnologías de Información y Electrónica; Campus Monterrey; Garza Salazar, DavidEn este trabajo se presenta el diseño y la modelación de un microescaner de barrido resonante para sistemas de imagenología biomédica con énfasis en aplicaciones endoscópicas. El dispositivo óptico diseñado consiste en una lente de campo plano y un espejo microelectromecánico con 22,032 µm2 de superficie. El microespejo es impulsado por seis de actuadores térmicos bimorfos, cada uno con 200 µm de longitud y 18 µm de ancho. Los parámetros estructurales y geométricos del microespejo fueron diseñados para ser compatibles con las reglas de diseño de la tecnología CMOS de 0.6 µm. Las características de enfoque y exploración de este dispositivo permiten su aplicación en sistemas endoscópicos de tomografía óptica para realizar los barridos transversales del haz láser en el tejido biológico en estudio. Para modelar el microespejo se utilizó la teoría clásica de Euler-Bernoulli y se obtuvieron las ecuaciones matemáticas que determinan la dependencia de su comportamiento estático y dinámico con las dimensiones y las propiedades físicas de los materiales empleados en su fabricación. A partir de los modelos obtenidos, se optimizó el proceso de diseño de manera que es posible minimizar el consumo de potencia de los actuadores térmicos y se propuso utilizar el nodo estacionario del segundo modo de vibración como un eje de rotación adicional sin translación para incrementar el ángulo de deflexión y la velocidad de exploración. Los resultados obtenidos en los modelos analíticos, para la deformación termomecánica generada por el efecto Joule así como para los modos naturales de vibración, concuerdan con las simulaciones realizadas por métodos de elementos finitos y demuestran que el desempeño del microespejo es superior en comparación con otros diseños reportados en publicaciones previas.
- Development of a tunable and resealable porous membrane for organ-on-a-chip devices(Instituto Tecnológico y de Estudios Superiores de Monterrey) Corral Nájera, Kendra; MARTINEZ CHAPA, SERGIO OMAR; 31803; Martínez Chapa, Sergio Omar; tolmquevedo, emipsanchez; Gallo Villanueva, Roberto Carlos; School of Engineering and Sciences; Campus Monterrey; Aeinehvand, MohammadMahdiOrgan-on-a-chip platforms are a promising technology for research in biotechnology, tissue engineering and pharmaceutical fields. They enable the study of physiological processes, facilitating the development of new drugs and broadening the understanding of the effects of mechanical and chemical cues in different cell lines. A very crucial role in these devices is played by porous membranes, which separate chamber content while allowing substance exchange through micro or nano pores. Additionally, it is the membrane that supports the cell culture and may provide actuation. Available porous membranes however do not possess resealability nor tunability features. This thesis presents a comprehensive review of organ-on-a-chip applications and the role of porous membranes within them, as well as membrane actuation methods and fabrication techniques. It also demonstrates the development of novel tunable and resealable porous PDMS membranes of different thicknesses, fabricated using fast and inexpensive prototyping methods for their integration into microfluidic plastic chips. Membrane deformation and pore opening were studied as a function of liquid flow rate. Pore opening increased with higher flow rates, demonstrating the tunability of pore opening useful for toxicological or pharmacological applications that require controlled transfer of substances or particles between chambers. The proof-of-concept study of a tunable and resealable porous membrane presented in this thesis is expected to motivate future works in smart membranes embedded in organ-on-a-chip devices to increase the system’s representativity and better emulate organs in vitro.