Digital Microfluidics

Optimal Strategies for Moving Droplets in Digital Microfluidic Systems

Team Members

Karl F. Böhringer


In digital microfluidic systems, analyte droplets (typically «1µl) are transported by electrowetting-on-insulator (EWOD) via an array of electrodes. While recent work has demonstrated mostly single droplets on small arrays, future commercial systems may simultaneously move many droplets on large arrays. This work introduces a broadly applicable approach to optimally control digital microfluidic systems; i.e., we present software that generates a sequence of control signals for moving one or many droplets from start to goal positions in the shortest number of steps, subject to constraints such as minimum separation between droplets, obstacles on the array surface, and limitations in the control circuitry.
Figure 1: Two droplets moving simultaneously on a 66 array while avoiding an obstacle (black cells). The two droplets start at cells (5,2) and (4,5), and require 8 steps to trade places.

The software can be downloaded here. Use of this software is permitted as long as

  1. it is used for academic research only
  2. the author is acknowledged in all resulting work
  3. modifications and extensions are made available to the author.

Caveat: this is work in progress and the sortware is currently neither implemented nor documented well!

Selected Publications

  • Karl F. Böhringer, "Towards Optimal Strategies for Moving Droplets in Digital Microfluidic Systems." IEEE International Conference on Robotics and Automation (ICRA), New Orleans, April 26 - May 1, 2004. Paper.
  • Karl F. Böhringer, "Optimal Strategies for Moving Droplets in Digital Microfluidic Systems." Seventh International Conference on Miniaturized Chemical and Biochemical Analysis Systems (MicroTAS'03), Squaw Valley, CA, October 5-9, 2003. Paper. Poster.

A complete list of our publications (many of them available online) can be found here.


  • National Science Foundation award CCR-0342632.

© Karl F. Böhringer, Department of Electrical Engineering, Box 352500, Seattle, WA 98195-2500, USA