If you have any problems related to the accessibility of any content (or if you want to request that a specific publication be accessible), please contact us at firstname.lastname@example.org.
Dielectrophoretic Cell Trapping for Media Exchange on a Microfluidic Algal Cultivator
AuthorWong, Johnson JhyRong
AdvisorGeiger, Emil J.
AltmetricsView Usage Statistics
Through COMSOL modeling and electrode design, positive dielectrophoretic (pDEP) cell trapping for media exchange has been demonstrated on live Chlamydomnas reinhardtii (C. reinhardtii)microalgae cells in regular growth medium in a PDMS-glass microfluidic MEMS device. Dielectrophoresis (DEP) is the force applied to dielectric particles in a non-uniform alternating current (AC) electric field. A DEP force toward the increasing electric field gradient is called positive. In literature pDEP trapping over large areas has been demonstrated with the use of low conductivity suspending media, while for higher conductivity suspending media, such as growth media, the pDEP force is reduced, and less likely to trap and hold microalgae against the hydrodynamic forces during media exchange. Media exchange allows for the removal of cellular waste and replenishment of nutrients. Multiphysics software, COMSOL, was used to model repeating structures suited for trapping of cells over an area of a microfluidic device. For single shell model, dielectrophoretic force on a homogenous sphere in a homogenous medium in an electric field is a function of the sphere radius, particle conductivity and permittivity, medium conductivity and permittivity, and the gradient of the electric field. By assuming the conductivities, permittivities, and the particle geometry remains constant, the gradient of the electric field is the determining factor for the strength of the pDEP force. Modeling the electric fields and the resulting electric field gradient of various interdigitated electrode configurations allowed for the optimization of an electrode structure’s area of higher electric field gradients. The completed microfluidic device consisted of a single channel and a wide growth chamber overlaid over patterned gold-chrome electrodes fabricated using soft lithography and photolithography. The pDEP trapping was successful in trapping C. reinhardtii for media exchange.