A bi-layer digital microfluidic structure is introduced. The integrated design employs a two-dimensional structure with perpendicular linear electrode arrays controlling x- and y- directional actuation. The introduced structure is capable of electrowetting-based fluid control, and it is presented here as an implementation capable of electrical sensing of the state of fluids within the device. The state of conductive fluids within the bi-layer structure is sampled through differential measurements of conductance values between the x- and y-channels. It is shown here that the features of microdroplets within the device can be effectively mapped onto these differential conductance measurements. An electronic acquisition system is ultimately employed to sense these conductance states and extract the position and size of microdroplets within the device. The complete system is demonstrated here for both single microdroplet and multiple microdroplet implementations.

Date Published: 11 May 2009
PDF: 9 pages
Proc. SPIE 7318, Micro- and Nanotechnology Sensors, Systems, and Applications, 73181C (11 May 2009); doi: 10.1117/12.817215

Published in SPIE Proceedings Vol. 7318:
Micro- and Nanotechnology Sensors, Systems, and Applications
Thomas George; M. Saif Islam; Achyut K. Dutta, Editor(s)