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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- DC-Voltage reduction for electrokinetic particle trapping in PDMS-based microfluidics(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2020-11-29) Ramírez Murillo, Cinthia Janet; Pérez González, Víctor Hugo; 349700; Pérez González, Víctor Hugo; puelquio/mscuervo; Gallo Villanueva, Roberto Carlos; Trujillo de Santiago, Grissel; Escuela de Ingeniería y Ciencias; Campus MonterreyThe objective of this work is to reduce the voltage requirement for particle manipulation and trapping in an insulator-based microfluidic channel. Insulator-based microfluidic devices have been used in the past for particle analysis, separation, and concentration. Although some efforts have been successfully carried out to manipulate particles in microfluidic channels of this type, the electric fields required for particle movement and trapping are generally higher than 100 V cm-1, limiting the possibility of creating an integrated, portable device that is suitable for point-of-care applications. Starting with a two-post geometry for the insulating feature in our channel, we amplify the electric field at the center of the channel through dimensional optimization of the constriction and the post diameter, lowering the voltage required to be applied across the channel in order to achieve particle displacement and trapping. The present work includes the fabrication and experimental trapping results obtained in the channel designs produced after a modelling and optimization process to select the most efficient geometries to be created.
- Modelling and simulation of an insulator-based DEP microdevice(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2007-11-01) Collado Arredondo, Esther; Martinez Chapa, Sergio Omar; Lapizco Encinas, Blanca H.; Dieck Assad, Graciano; Lapizco Encinas, Blanca H.; Bouchereau Lara, Frantz; Programa de Graduados; División de Electrónica, Computación, Información y Comunicaciones; Campus MonterreyThe current work presents a finite element method (FEM) model of a microchannel for particle separation using dielectrophoresis (DEP). The model is based on the commercial software COMSOL and Matlab was used to postprocess the FEM results. The microchannel layout consists of an array of insulating cylindrical posts in the midsection of the microchannel, etched in glass. The microchannel was filled with a ionic solution whose pH and conductivity were fixed to known values, by adding NaOH and K2HPO4. A series of experiments had to be conducted. In each experiment, the microchannel was filled with the ionic solution, a sample of fluorescent microspheres was injected in the inlet, and a DC electric field was applied across the channel using Pt electrodes The experiments were recorded using a camera coupled to a microscope. The electrokinetic mobility, which depends on the pH and the conductivity, was estimated using the particle image velocimetry (PIV) method from the captured videos. The insulating posts in the microchannel produce a non-uniform electric field distribution, which in turn generates a dielectrophoretic (DEP) force on the submerged particles. The DEP force competes with the fluid drag force exerted on the particles. At a certain voltage value, particles are trapped. The FEM model used the estimated electrokinetic mobility to predict the trapping voltage and to calculate the particle trajectories. This research work is a preliminary step in characterizing the dielectrophoretic microchannel, whose final target is to be used for the concentration, separation and identification of biological cells.