A Droplet-Manipulation Method for Achieving High-Throughput in Cross-Referencing-Based Digital Microfluidic Biochips

Digital microfluidic biochips are revolutionizing high-throughput DNA, immunoassays, and clinical diagnostics. As high-throughput bioassays are mapped to digital microfluidic platforms, the need for design automation techniques for pin-constrained biochips is being increasingly felt. However, most prior work on biochips computer-aided design has assumed independent control of the underlying electrodes using a large number of (electrical) input pins. We propose a droplet-manipulation method based on a ldquocross-referencingrdquo addressing method that uses ldquorowrdquo and ldquocolumnsrdquo to access electrodes. By mapping the droplet-movement problem on a cross-referenced chip to the clique-partitioning problem from graph theory, the proposed method allows simultaneous movement of a large number of droplets on a microfluidic array. Concurrency is enhanced through the use of an efficient scheduling algorithm that determines the order in which groups of droplets are moved. The proposed design-automation method facilitates high-throughput applications on a pin-constrained biochip, and it is evaluated using random synthetic benchmarks and a set of multiplexed bioassays.