FT-MUX: A Fault-Tolerant Microfluidic Multiplexer Design

Continuous-flow microfluidic chips are multilayered miniaturized platforms to manipulate small volumes of fluids with valves. There are two types of channels on a chip: flow channels for the reaction of fluids, and control channels for the actuation of valves. Multiplexers (MUXes) are essential microfluidic components for individually addressing many flow channels with few control channels. As the integration scale of microfluidic chips increases, the reliability of MUXes becomes a critical concern, as a single defective control channel in a MUX will affect a large part of the flow channels addressed by the MUX. This paper formally analyzes and identifies the design rules for a MUX to tolerate n defective control channels, and model the fault-tolerant MUX (FT-MUX) design problem as a binary constant weight code problem to minimize resource overheads. We demonstrate that FT-MUX improves resource efficiency by up to hundreds of times compared to the conventional fault-tolerant design method. Besides, given no less than 10 control channels, FT-MUX tolerates at least one defective control channel and addresses even more flow channels with equal or fewer resources than a standard MUX. The advantages become more significant as the integration scale increases.