Co-optimization of droplet routing and pin assignment in disposable digital microfluidic biochips

Abstract

The number of independent input pins used to control the electrodes in digital microfluidic biochips is an important cost-driver in the emerging market place, especially for disposable PCB devices that are being developed for clinical and point-of-care diagnostics. However, most prior work on pin-constrained biochip design considers droplet routing and the assignment of pins to electrodes as independent problems. We propose aninteger linear programming (ILP)-based optimization method to solve the droplet-routing and the pin-mapping design problems concurrently. The proposed co-optimization method optimizes routing pathways, generates a single pin-assignment, and attempts to minimize the number of control pins. It also overcomes a major limitation of recent work on this problem---the method described in prior work can lead to infeasible designs due to the need to change the mapping of pins to electrodes dynamically during bioassay execution. The effectiveness of the proposed co-optimization method is demonstrated for a commercial biochip that is used to perform n-plex immunoassays, as well as an experimental chip for multiplexed in-vitro diagnostics.