FIG. 6.

Origami-inspired paper-based microfluidic devices. (a) 100 μm thick chromatography paper that has photolithographically patterned channels, reservoirs, and a folding frame. The channels are 900 μm wide while the reservoirs are 2.5 mm in diameter. (b) The top layer of the device after the paper is folded, depicting four inlet reservoirs in the center of the device. There are also four flanking circular features that are located within the 3D device but are visible due to the transparency of the paper. (c) The bottom layer of the folded device. (d) Aluminum housing that supports the 3D device. The four corners of the device were cut so the device could be clamped, as seen in (d). The four drilled holes on the top of the housing system are utilized to inject solutions. (e) The unfolded, nine-layer paper device after the injection of four 1.0 mM, aqueous, colored solutions through the four injection ports in the aluminum housing device. The four colored solutions (rhodamine 6G, red; erioglaucine, blue; tatrazine, yellow; and a mixture of erioglaucine and tatrazine, 1:10, green) traveled through their desired channels without mixing.¹²¹ Reproduced with permission from Liu et al., J. Am. Chem. Soc. 133(44), 17564–17566 (2011). Copyright 2011 American Chemical Society.