Fast reconfigurable paper-based flow switch

  

This paper presents the development of a unique actuator device made from chromatography paper and incorporating folds. Upon selective wetting of the fold with an actuation fluid, either at the crest or trough, the tip of the actuator is raised or lowered, thereby engaging or breaking the fluid connection between channels. This reduces the response time to within two seconds from wetting and requires only four microliters of actuation fluid. Six switch configurations are implemented, including single-pole single-throw (normally OFF and normally ON) and single-pole double-throw (with single and double break). This technology is then used in an autonomous colorimetric assay that can detect glucose, protein, and nitrite in artificial saliva. Additionally, this work expands upon the origami concept in paper microfluidics by using multiple-fold geometries for the programmable switching of fluidic connections.

  

Kong, T., Flanigan, S., Weinstein, M., Kalwa, U., Legner, C., & Pandey, S. (2017). A fast, reconfigurable flow switch for paper microfluidics based on selective wetting of folded paper actuator strips. Lab on a Chip, 17(21), 3621–3633. https://doi.org/10.1039/C7LC00620A

https://pubs.rsc.org/en/content/articlelanding/2017/LC/C7LC00620A