Interference-Free Design Methodology for Paper-Based Digital Microfluidic Biochips

Paper-based digital microfluidic biochips (P-DMFBs) have recently attracted great attention for its low-cost, in-place, and fast fabrication. This technology is essential for agile bio-assay development and deployment. P-DMFBs print electrodes and associate control lines on paper to control droplets and complete bio-assays. However, P-DMFBs have following issues: 1) control line interference may cause unwanted droplet movements, 2) avoiding control interference degrades assay performance and routability, 3) single layer fabrication limits routability, and 4) expensive ink cost limits low-cost benefits of P-DMFBs. To solve above issues, this work proposes an interference-free design methodology to design P-DMFBs with fast assay speed, better routability, and compact printing area. The contributions are as follows: First, we categorize control interference into soft and hard. Second, we identify only soft interference happens and propose to remove soft control interference constraints. Third, we propose an interference-free design methodology. Finally, we propose a cost-efficient ILP-based fluidic design module. Experimental results show proposed method outperforms prior work [14] across all bio-assay benchmarks. Compared to previous work, our cost-optimized designs use only 47%~78% area, gain 3.6%~16.2% more routing resources, and achieve 0.97x~1.5x shorter assay completion time. Our performance-optimized designs can accelerate assay speed by 1.05x~1.65x using 81%~96% printed area.