Wisconsin Alumni Research Foundation

Analytical Instrumentation, Methods & Materials
Analytical Instrumentation Methods Materials
Improved Method of Pumping Fluid through a Microfluidic Device
WARF: P07126US

Inventors: David Beebe, Glenn Walker, Jay Warrick, Michael Toepke, Ivar Meyvantsson

The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in developing an improved passive pumping system for microfluidic devices.
Although there are several techniques for pumping fluid through the channels of microfluidic devices, almost all of these methods require expensive or complicated external equipment. UW-Madison researchers previously developed a simple and inexpensive passive pumping method, which is semi-autonomous and requires only minimal additional hardware. That method relies on differences in surface tension between input and output fluid droplets at the ports on either end of the microchannel to pump fluid through the device.
The Invention
UW-Madison researchers now have improved their passive pumping method. Like the previous method, this system is simple and inexpensive, requiring little additional equipment. Unlike the original microfluidic system, the improved version does not require an output drop. Instead, multiple input pumping drops are used.

In the original device, one of the ports had multiple pores, allowing a greater target area for robotic fluid systems. In the new design, a star-shaped entrance to the microchannel replaces the multiple pores, creating a more uniform fluid flow profile. In addition, the input port itself, rather than just the input droplet, is smaller in this new design, and a tapered port is used to ensure constant contact angle while the droplet shrinks or expands. This change ensures that driving pressure, which is related to contact angle, remains constant.

Geometry and patterning changes in the improved system also provide more versatile port-to-port interactions, including the manipulation of droplet movement to another channel. For example, fluid resistance in the first channel could be designed to create a timing mechanism for autonomous fluid replacement, such as biological waste removal, in a second channel.
  • Passive pumping of fluid through a microfluidic device
Key Benefits
  • Simple and inexpensive
  • Does not require an output droplet
  • Star shape entrance increases uniform flow profiles because droplets translate along an arm to the center of the star, unlike the multiple pore design, which may not have centered flow.
  • Increases flow velocity, while decreasing the volume of fluid needed
  • Enables the manipulation of flow direction
  • Could be used to create a mechanism for autonomous removal of biological waste or to send conditioned medium from one channel to the next
  • Does not require expensive or complicated external equipment
  • Works with many types of fluids, including water and fluid media containing cells and other biological components
  • Compatible with pre-existing robotic systems
  • Can be used to develop an improved microchannel plate that provides a direct, drop-in replacement for standard microtiter plates
Additional Information
For More Information About the Inventors
Related Intellectual Property
For current licensing status, please contact Jeanine Burmania at [javascript protected email address] or 608-960-9846