Application Mapping and Control-system Design for Microfluidic Biochips with Distributed Channel Storage

Abstract

Continuous-flow microfluidic biochips have emerged as a potential low-cost and fast-responsive lab-on-chip platform. They have attracted much attention due to their capability of performing various biochemical applications concurrently and automatically within a coin-sized chip area. To improve execution efficiency and reduce fabrication cost, a distributed channel-storage architecture can be implemented in which the same channels can be switched between the roles of transportation and storage. Accordingly, fluid transportation, caching, and fetch can be performed simultaneously through different flow paths. Such a flow-path planning needs to be considered carefully in the mapping procedure from a biochemical application to a given biochip architecture. Moreover, all the on-chip valves should be actuated correctly and promptly to temporally block the fluid transportation in unwanted directions and seal the fluids in caching channels. Such an exact control of the valves needs to be considered systematically in control-system design to support the mapping scheme for bioassay execution. In this article, we formulate the practical mapping-control co-design problem for microfluidic biochips with distributed channel storage, considering application mapping, valve synchronization, and control-system design simultaneously, and present an efficient synthesis flow to solve this problem systematically. Given the protocol of a biochemical application and the corresponding chip layout in the flow layer, our goal is to map the biochemical application onto the chip with short execution time. Meanwhile, a practical control system considering the real valve-switching requirements can be constructed efficiently with low fabrication cost. Experimental results on multiple real-life bioassays and synthetic benchmarks demonstrate the effectiveness of the proposed design flow.