A pulsed source-sink fluid mixing device

Efficient fluid mixing can be achieved in a high-aspect-ratio volume by periodically pulsing an arrangement of source-sink pairs. In order to conserve fluid and promote mixing, the fluid extracted through a sink is subsequently injected through a source. We present an implementation of this approach that consists of a disposable chip with embedded microchannels and external fluidic control. When both the mixing chamber geometry and the source-sink arrangement are fixed, mixing is controlled by choosing [alpha], the fraction of the mixing chamber volume that is exchanged with each pulse. Experimental results in a rectangular chamber show that the value of [alpha] has a significant effect on mixing efficiency. This device shows promise for enhancing the performance of massively parallel sensing systems such as DNA microarrays. [1592] Index Terms--Chaotic advection, Hele-Shaw flow, microelectromechanical systems (MEMS), microfluidics, mixing.