A Low-Cost Field-Programmable Pin-Constrained Digital Microfluidic Biochip

This paper introduces a field-programmable pin-constrained digital microfluidic biochip (FPPC-DMFB), which offers general-purpose assay execution at a lower cost than general-purpose direct addressing DMFBs and highly optimized application-specific pin-constrained DMFBs. One of the key cost drivers for DMFBs is the number of printed circuit board (PCB) layers, onto which the device is mounted. We demonstrate a scalable single-layer PCB wiring scheme for several FPPC-DMFB variations, for PCB technology with orthogonal routing capacity of at least three; for PCB technology with orthogonal capacity of two, more PCB layers are required, but the FPPC-DMFB retains its cost advantage. These results offer new insights on the relationship between PCB layer count, pin count, and cost. Additionally, to reduce the execution time of assays on the FPPC-DMFB, we present efficient algorithms for droplet routing, with and without contamination removal via wash droplets.