CoMUX: Combinatorial-coding-based high-performance microfluidic control multiplexer design

Flow-based microfluidic chips are one of the most promising platforms for biochemical experiments. Transportation channels and operation devices inside these chips are controlled by microvalves, which are driven by external pressure sources. As the complexity of experiments on these chips keeps increasing, control multiplexers (MUXes) become necessary for the actuation of the enormous number of valves. However, current binary-coding-based MUXes do not take full advantage of the coding capacity and suffer from the reliability problem caused by the high control channel density. In this work, we propose a novel MUX coding strategy, named Combinatorial Coding, along with an algorithm to synthesize combinatorialcoding- based MUXes (CoMUXes) of arbitrary sizes with the proven maximum coding capacity. Moreover, we develop a simplification method to reduce the number of valves and control channels in CoMUXes and thus improve their reliability. We compare CoMUX with the state-of-the-art MUXes under different control demands with up to 10 × 213 independent control channels. Experiments show that CoMUXes can reliably control more independent control channels with fewer resources. For example, when the number of the to-be-controlled control channels is up to 10 × 213, compared to a state-of-the-art MUX, the optimized CoMUX reduces the number of required flow channels by 44% and the number of valves by 90%.