Figure 1.

Concept for the microfluidic Jukebox: (a) Microfluidic chip as interfaced on the microscope. The yellow reflection shows the electrodes patterned around a flow focusing junction. The blue line in the middle is the 473 nm laser scattered by the PDMS. The corresponding optical setup is described as Supplementary Figure 1. (b) Detail on the fluidic and electrical connections at the flow focusing junction. Optical micrograph of the chip recorded using the high-speed camera in bright field for three values of applied voltage U (c,d,e). The voltage is applied on the chip between the downstream and upstream pairs of electrodes. Corresponding droplet fluorescence signal recorded through the sound card (f,g,h). Each peak corresponds to a droplet flowing through the laser. The signal is high-pass filtered by the sound card at 50 Hz leading to the base line modulation. The corresponding videos are available as Supplementary Materials.