Electrical Textile Valves for Paper Microfluidics

This paper describes electrically-activated fluidic valves that operate based on electrowetting through textiles. The valves are fabricated from electrically conductive, insulated, hydrophobic textiles, but the concept can be extended to other porous materials. When the valve is closed, the liquid cannot pass through the hydrophobic textile. Upon application of a potential (in the range of 100–1000 V) between the textile and the liquid, the valve opens and the liquid penetrates the textile. These valves actuate in less than 1 s, require low energy (≈27 µJ per actuation), and work with a variety of aqueous solutions, including those with low surface tension and those containing bioanalytes. They are bistable in function, and are, in a sense, the electrofluidic analog of thyristors. They can be integrated into paper microfluidic devices to make circuits that are capable of controlling liquid, including autonomous fluidic timers and fluidic logic.

Textile valves based on an electrowetting principle and their use in paper microfluidics are presented. These valves can be integrated into paper-based microfluidics monolithically, require no mechanically moving parts, are fast, require low energy, and work with a variety of aqueous solutions. Furthermore, such valves can be combined into self-regulating autonomous circuits and used for reagent addition in assays.

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