Office for Technology Commercialization

Unidirectional Microfluidic Channels

Technology #20170306

Questions about this technology? Ask a Technology Manager

Download Printable PDF

Image Gallery
Unidirectional FlowMicrofluidic ChannelCapillary Flow Flow Control
C. Daniel Frisbie, PhD
Distinguished McKnight University Professor Chemical Engineering and Materials Science
External Link (
Lorraine Francis, PhD
Professor, Chemical Engineering and Materials Science
External Link (
Managed By
Larry Micek
Technology Licensing Officer 612-624-9568
Patent Protection

Provisional Patent Application Filed
Files and Attachments
Non-confidential Summary [PDF]
Pinned Flow [MP4]
Unpinned Flow [MP4]

Microfluidic Diode Structure - Can Be Used for Pinning or Filling

View video:
Pinning Direction
Filling Direction

Controls Capillary Flow in Microfluidic Channels

A microfluidic channel structure limits capillary flow to one direction, offering an effective method to control capillary flow in microfluidic channels. This structure is very versatile since unidirectional flow is independent of liquid contact angle and surface tension. Connected small and large channels are designed so a fluid will not flow beyond the joint of the channels (it is pinned) when flowing from the smaller channel to the larger channel, but it flows from the larger channel to the smaller channel without pinning. The channel structure is fabricated by two photolithography cycles; first the smaller channel is etched, and then the larger channel is etched with an overlap on the smaller channel. This channel structure and fabrication process can be used to control fluid flow in microfluidic applications.

Flow Control at Low Contact Angles

Precise control of fluid flow in complicated microfluidic channels is required for microfluidic applications. While many ways to control fluid flow in a microfluidic device exist, easily fabricated, alternative ways to control fluid flow are desired. For example, while channel topography offers unidirectional capillary flow in microfluidic channels, it requires a high contact angle between the fluid and substrate. This novel structure facilitates fluid flow control at low contact angles and enables control of diverse fluids and substrates within complicated microfluidic channels.


  • Allows capillary flow in only one direction
  • Controls capillary flow in microfluidic channels
  • Adaptable to variety of fluids


  • Flexible, printable electronics (e.g., wearable electronics, lab on a chip, disposable electronics, etc.)
  • Microfluidic devices
  • Capillary lithography

Phase of Development - Working prototype

Interested in Licensing?
The University relies on industry partners to scale up technologies to large enough production capacity for commercial purposes. The license is available for this technology and would be for the sale, manufacture or use of products claimed by the issued patents. Please contact Larry Micek to share your business needs and technical interest in this microfluidic channel flow control technology and if you are interested in licensing the technology for further research and development.