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

Abstract

Abstract-This paper introduces a field-programmable pinconstrained 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.Index Terms-Digital microfluidic biochip (DMFB), PCB escape routing, pin-constrained DMFB.

An open-source compiler and PCB synthesis tool for digital microfluidic biochips

“…We report the number of PCB layers and the number of control pins required to realize each chip; as reported by Grissom et al [25], these two factors are the primary drivers for total chip cost, and the number of PCB layers plays a more significant role.…”

“…Reducing the number of control inputs reduces the two-dimensional area of the PCB, which in turn, reduces cost. Both application-specific [9,[33][34][35][36][37]40,41,56,76,79,80,[84][85][86] and general-purpose [20,25,46] pin assignments have been reported in the literature. Wire routing connects each control input to the one or more electrodes that it drives, and determines the number of PCB layers required to realize the chip; reducing the number of layers also reduces cost.…”

“…The data structure that represents assignment of control pins to electrodes in the array is an internal data structure that is "owned" by the architecture. The literature on pin-constrained DMFB design is vast, and includes: (1) pre-computed pin mappings that require specialized scheduling, placement, and routing algorithms [20,25,46]; (2) "pre-synthesis" array partitioning methods that update the pin-map during scheduling, placement, and routing [9,33,40,41,56,[84][85][86]; and (3) "post-synthesis" pin assignment algorithms that derive a pin-map (and, in some cases, a wire routing solution) starting with a fully-compiled assay [34,36,37,76,79,80,86]. Rather than extending the framework to include every possible ordering of tasks vis-à-vis pin assignment algorithms, we set up an initial direct addressing pinmap before scheduling.…”

“…We have also implemented several droplet routing algorithms that are specific to a general-purpose pin-map that we call a field-programmable pin-constrained DMFB (FPPC-DMFB) [20,25].…”

Improved experimental time of ultra‐large bioassays using a parallelised microfluidic biochip architecture/scheduling

“…The number of pins and PCB layers are a cost proxy, but cannot report the actual costs. We used [29] to estimate the cost of the mentioned architectures. To estimate the cost of PCB, we use advanced circuits online instant quote feature [30] based on the required parameters.…”