This work integrates components from AC electrokinetics, microfluidics, and cell biology to produce tunable spatial chemical gradients in a...
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This work integrates components from AC electrokinetics, microfluidics, and cell biology to produce tunable spatial chemical gradients in a microfluidic device for studying directed cell migration. I explore a new type of Maxwell Wagner polarization for the injection of aqueous liquid across a liquid-liquid interface. The rate of injection is tunable and used to manipulate fluid much the same way dielectrophoresis is used on bioparticles; fluid can be injected into different streamlines and passed downstream to a gradient generator only when the electric field is active. The phenomenon is used to generate and control the concentration and direction of spatial chemical gradients. Finally, the controllable gradient is used to explore directed cell migration. In particular, the social amoeba Dictyostelium discoidium is shown to respond to an induced chemical gradient by migrating from low to high concentrations of cyclic 3’,5’-adenosine monophosphate (cAMP) only when the electric field is active. The end result is a new type of liquid-liquid polarization that can controllably inject fluid to create controllable microenvironments for biological studies.
