J. Am. Chem. Soc. 133, 17564–17566 (2011)

Paper-based microfluidic devices can potentially serve as cheap and disposable tools for analytics and diagnostics. To create a three-dimensional system of liquid reservoirs and channels, however, several sheets of paper need to be patterned, stacked and aligned in a lengthy process. Hong Liu and Richard Crooks now report an origami-inspired scheme for the simple fabrication of microfluidic devices from a single folded piece of chromatography paper. Using photolithography, the researchers pattern channels, reservoirs and a frame on the paper. The frame then guides the folding and ensures that the elements of the microfluidic system are aligned before the paper is clamped between two metal plates with access holes. Using a five-layer design, the researchers demonstrate a simple colorimetric assay for glucose and bovine serum albumin, which allows them to detect the analytes separately on two different layers of the system. They suggest that their process could be used for the automated fabrication of paper-based microfluidic devices, and that more complex systems could be designed by increasing the number of folds.