Droplet generators.

<p>(a) The T-junction device was operated with the fluorescein flow rate at 1μl/min and the oil at (a1) 5μl/min and (a2) 20μl/min. (b) The flow-focusing device operates with the same flow rates. (b1-2) show the oil channels pinching off a droplet from the fluorescein channel. (c) Formed droplets are highly replicable and can be controlled by altering the oil flow rate from 2μl/min to 20μl/min.