Investigation of Electroosmotic Flow in Various Microfluidic Structures
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Date
2010-04
Authors
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Publisher
Vanderbilt University. Dept. of Physics and Astronomy
Abstract
Enclosed microfluidic devices provide excellent systems for the study of
biological processes such as cell-cell, paracrine, and autocrine signaling
systems. By minimizing the fluid volume within the chambers, microfluidic
devices diminish the dilution of secreted products which makes the detection
of the secreted products a more straightforward task. A major design problem
associated with the construction of microfluidic devices for biological
research is the need to provide well-controlled fluidic transportation for
cells, the nutrients that the cells need, and waste removal. Most precision
syringe pumps which can accurately provide low flow rates are expensive and
constitute a barrier to experiment design. Electroosmotic pumps could
potentially provide a valuable alternative as a low volume flow rate pumping
system for many types of microfluidic devices. We have developed a
poly(dimethylsiloxane) (PDMS) microfluidic device that incorporates both
electroosmotic flow and pressure driven flow. The device is designed to
increase the relative strength of the electroosmotic flow (EOF) component of
the total flow through the use of an array of small volume parallel pumping
channels which provide higher passive resistance to pressure driven flow
than a larger volume single-channel EOF pump. Using a novel microfluidic
instrumentation device which we call the "Micro Programmable Object
Navigation Gadget" (µ-PONG), we investigate how different properties and
geometries of the device affect the EOF rate. In addition, we demonstrate
that fluid flow driven by a small hydraulic pressure head can be completely
canceled by an user initiated EOF in the pumping channels which are
incorporated into a microfluidic device. The ability to modulate the flow
and to create "stop flow" conditions in microfluidic devices is also
important for biological research.
Description
Highest Honors in Physics
Keywords
Electrokinetic flow, Electroosmotic flow, Poiseuille flow, MEMS, Poly(dimethylsiloxane), Particle imaging