Electroosmotic Dispensing

Electrohydrodynamic dispensing Electrokinetic injection Electroosmotic dispensing... 

An important component of many bio- or chemical lab-chips is the microfluidic dispenser, which employs electroosmotic flow to dispense minute quantities (e.g., 300 pico-liters) of samples for chemical and biomedical analysis. The precise control of the dispensed sample in microfluidic dispensers is key to the performance of these lab-on-a-chip devices. 

Because the electroosmotic flow field reaches steady state in milli-seconds, much shorter than the characteristic time scales of the sample loading and sample dispensing. Therefore, the electroosmotic flow here is approximated as steady state. Furthermore, we consider thin electrical double layer, and use the slip flow boundary condition to represent the electroosmotic flow. The liquid flow field can thus be described by the following non-dimensional momentum equation and the continuity equation. 

In the development of lab-on-a-chip technology, a key is to develop the ability to pump the liquids and transport sample/reagent molecules as well as biological cells in a microchannel network. This can be achieved by using the electroosmotic flow and electrophoresis. Mixing of different solutions and dispensing a specified amount of one solution from one microchannel into another microchannel are important to many microfluidic chips. There are extensive research works done in these areas [1]. Furthermore, precise control of temperature is often critical to on-chip biochemical reactions. In the following the PCR lab-on-a-chip, flow cytometer lab-on-a-chip and immunoassay lab-on-a-chip will be reviewed. 

Electrokinetic dispensing is a method using electroosmotic pumping to inject a small quantity of... 

Electrokinetic dispensing is a method using electroosmotic punqting to inject a small quantity of samples, the size and concentration of which can be controlled by manipulating applied electrical potential fields, modifying channel surfaces and changing channel dimensions. A simple cross-linked microchannel is commonly employed for electrokinetic dispensing. 

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