Design and application of a self-pumping microfluidic staggered herringbone mixer

The rapid mixing of reagents is critical to a wide range of chemical and biological reactions but is difficult to implement in microfluidic devices, particularly in capillary action/passive pumping devices or in point-of-need environments. Here, we develop a self-pumping asymmetric staggered herringbone mixer made from only laser-ablated glass and tape. This lab-on-a-chip platform is capable of rapid flow (0.14 mL min−1, 1 cm s−1) and fast mixing (< 10 s) without external forces or pumps and is amenable to the flow of non-aqueous solvents. Furthermore, the degree of mixing and flow rates are easily tunable through the length and depth of the herringbone grooves, and the thickness of the double-sided tape that defines the channel height, respectively. The device utility is demonstrated for chemical and biological assays through the reaction of Ni(II) and DMG in ethanol/water and the enzymatic reaction of o-dianisidine with peroxidase, respectively.