Dielectrofóresis con estructuras aisladoras
Insulator–based dielectrophoresis
S. Ozuna–Chacón1, B.H. Lapizco–Encinas1*, M. Rito–Palomares2, E. Collado–Arredondo3 y S.O. Martínez–Chapa3
1 Departamento de Ingeniería Química y Centro de Biotecnología. Instituto Tecnológico y de Estudios Superiores de Monterrey, Campus Monterrey. Ave. Eugenio Garza Sada 2501 Sur, Monterrey, NL 64849, México. * Autor para la correspondencia: E–mail: blapizco@itesm.mx Tel. (81) 8158–2034,fax. (81) 8328–4250.
2 Departamento de Biotecnología e Ingeniería de Alimentos y Centro de Biotecnología. Instituto Tecnológico y de Estudios Superiores de Monterrey, Campus Monterrey. Ave. Eugenio Garza Sada 2501 Sur, Monterrey, NL 64849, México.
]]> 3 Departamento de Ingeniería Eléctrica. Instituto Tecnológico y de Estudios Superiores de Monterrey, Campus Monterrey. Ave. Eugenio Garza Sada 2501 Sur, Monterrey, NL 64849, México.
Recibido 5 de Abril 2007
Aceptado 28 de Septiembre 2007
Resumen
Existe en la actualidad un interés creciente en el desarrollo de laboratorios montados en un microdispositivo (lab–on–a–chip). Estos microsistemas portátiles realizan las funciones de un equipo de laboratorio convencional, con las ventajas de ser más rápidos y requerir menos muestra. Por este motivo las técnicas de separación aplicables en microescala están tomando cada vez mayor importancia. Entre estas técnicas se encuentra la dielectroforesis. La dielectroforesis es un mecanismo de transporte electrocinético, que ocurre en la presencia de un campo eléctrico no homogéneo. La dielectroforesis tiene un gran potencial para ser aplicada en la separación y concentración de biopartículas; ya que es una técnica no destructiva.
Con la dielectroforesis con estructuras aisladoras es posible atrapar y concentrar partículas dentro de microcanales, mediante la aplicación de un campo eléctrico. La magnitud de la fuerza dielectroforética depende de las condiciones de operación: geometría de las estructuras aisladoras, intensidad del campo eléctrico, concentración de las partículas, conductividad y pH del líquido de suspensión. El presente trabajo presenta un estudio paramétrico de la dielectroforesis producida con estructuras aisladoras con el fin de caracterizar el funcionamiento de un microdispositivo para dielectroforesis; y obtener las condiciones de operación óptimas que permitan concentrar y separar mezclas de partículas.
Palabras clave: dielectroforesis, electroforesis, electrocinética, flujo electroosmótico, microfluidica.
]]> Abstract
Recently there has been an increasing interest in the development of laboratories machined on microdevices (lab–on–a–chip). These portable microsystems would be able to accomplish the same tasks as conventional laboratory equipment, with the advantage of being faster and requiring a smaller sample volume. Thus, separation techniques on a microscale are acquiring a greater importance. Among these techniques, we can find the separation of particles by a dielectrophoretic force. Dielectrophoresis is an electrokinetic transport mechanism that occurs in the presence of a non–homogeneous electric field. Dielectrophoresis is a non–destructive technique with great potential for the separation and concentration of bioparticles.
Insulator–based dielectrophoresis makes it possible to trap and concentrate particles inside a microchannel by applying an electric field. The magnitude of the dielectrophoretic force depends on the operating conditions: insulating structures geometry, electric field intensity, particle concentration, conductivity and pH of the suspending buffer. This work presents a parametric study on insulator–based dielectrophoresis with the objected of characterizing the performance of a dielectrophoretic microdevice, and obtaining the optimal conditions for the concentration and separation of a mixture of particles.
Keywords: dielectrophoresis, electrophoresis, electrokinetics, electroosmotic flow, microfluidics.
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Agradecimientos
Los autores desean agradecer el apoyo económico de la Cátedra de Investigación del ITESM (CAT 005). Se agradece el apoyo a CONACYT en la modalidad de repatriación para la Dra. Lapizco Encinas. Los autores agradecen al M.C. Susheel Yadav y al Sr. Francisco Carmona por apoyo técnico con el equipo experimental.
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