Synthesis of biochemical applications on digital microfluidic biochips with operation variability

Abstract—Microfluidic-based biochips are replacing the con-ventional biochemical analyzers, and are able to integrate on-chip all the necessary functions for biochemical analysis using microfluidics. The digital microfluidic biochips are based on the manipulation of liquids not as a continuous flow, but as discrete droplets. Researchers have presented approaches for the synthesis of digital microfluidic biochips, which, starting from a biochemical application and a given biochip architecture, determine the allocation, resource binding, scheduling and place-ment of the operations in the application. Existing approaches consider that on-chip operations, such as splitting a droplet of liquid, are perfect. However, these operations have variability margins, which can impact the correctness of the biochemical application. We consider that a split operation, which goes beyond specified variability bounds, is faulty. The fault is detected using on-chip volume sensors. We have proposed an abstract model for a biochemical application, consisting of a sequencing graph, which can capture all the fault scenarios in the application. Starting from this model, we have proposed a synthesis approach that, for a given chip area and number of sensors, can derive a fault-tolerant implementation. Two fault-tolerant scheduling techniques have been proposed and compared. We show that, by taking into account fault-occurrence information, we can derive better quality implementations, which leads to shorter application completion times, even in the case of faults. The proposed synthesis approach under operation variability has been evaluated using several benchmarks. I

A high-performance droplet router for digital microfluidic biochips

In this paper, we propose a high-performance droplet router for digital microfluidic biochip (DMFB) design. Due to re-cent advancements in bio-MEMS, the design complexity and the scale of a DMFB are expected to explode in near fu-ture, thus requiring strong support from CAD as in con-ventional VLSI design. Among multiple design stages of a DMFB, droplet routing which schedules the movement of each droplet in a time-multiplexed manner is a critical chal-lenge due to high complexity as well as large impacts on per-formance. Our algorithm first routes a droplet with higher bypassibility which less likely blocks the movement of the others. When multiple droplets form a deadlock, our algo-rithm resolves it by backing off some droplets for concession. A final compaction step further enhances timing as well as fault-tolerance by tuning each droplet movement greedily. Experimental results on hard benchmarks show that our al-gorithm achieves over 35x and 20x better routability with comparable timing and fault-tolerance than the popular pri-oritized A * search [2] and the state-of-the-art network-flow based algorithm [18], respectively