Extended Data Fig. 3: SCM volume scaling experiments.

a, Bright-field microscope images of devices fabricated in silicon (numbered 1-1 to 1-5) in which volume scaling experiments were performed. As discussed in Fig. 1d, the velocity of the self-coalescing flow decays more quickly in narrower than in wider SCMs. In order to maintain a quick decay of the self-coalescing flow velocity in wide SCMs, the leading barrier is simply shifted towards the area in which reagents are deposited. Amaranth is deposited at 100 ng mm⁻¹ (250-µm pitch). A spotting alignment mark is used to align the inkjet spotter head with the microfluidic chips for precise targeting of the deposition location. b, Bright-field microscope images showing the amaranth solution in the meandering channels, reconstituted in the SCMs shown in panel a. c, Time series of bright-field microscope images showing the reconstitution of amaranth in a 1-mm-wide SCM (Q_in = 500 nl min⁻¹). Typically, in wide SCMs (wider than 0.5 mm), lateral homogenization of the reconstituted reagent is complete at the narrow outlet of the SCM (as seen here), and can be enhanced, if necessary, by adding a Dean vortex mixer, a chaotic mixer, or a simple meandering channel. Larger volumes of solution with reconstituted reagents can also be achieved using an array of parallel SCMs. SCMs are easily scaled; however, making them longer decreases the maximum filling flow rate because the pressure at the inlet needs to be lower than the Laplace pressure over the CPL.