High-speed on demand microfluidic droplet generation and manipulation
Methods and devices for the formation and/or merging of droplets in microfluidic systems are provided. In certain embodiments a microfluidic droplet merger component is provided that comprises a central channel comprising a plurality of elements disposed and spaced to create a plurality of lateral passages that drain a carrier fluid out of a fluid stream comprising droplets of a first fluid contained in the carrier fluid; and a deformable lateral membrane valve disposed to control the width of said center channel.
1. A microfluidic droplet merger component, said component comprising:
a central channel comprising a plurality of elements disposed on both sides of said central channel and spaced to create a plurality of lateral passages on both sides of said central channel that drain a carrier fluid out of a fluid stream comprising droplets of a first fluid contained in said carrier fluid; and
a deformable lateral membrane valve disposed to and configured to control the width of said central channel, wherein said lateral membrane valve is disposed downstream from said plurality of elements.
2. The droplet merger component of claim 1 , wherein the width of said central channel reduces as a function of distance downstream through said plurality of lateral passages.
3. The droplet merger component of claim 1 , wherein the width of said lateral passages is smaller than the width of said central channel at the same location and smaller than the average diameter of a droplet in the central channel.
4. The droplet merger component of claim 1 , wherein said plurality of elements comprise a micropillar array.
5. The droplet merger component of claim 4 , wherein said micropillar array comprises pairs of pillars that form lateral channels slanted in a downstream direction.
6. A device for the manipulation of microfluidic droplets, said device comprising a substrate carrying or comprising:
one or more droplet merger components according to claim 1 ; and
optionally one or more droplet generators.
7. The device of claim 6 , wherein said device further comprises a controller that controls the amount and timing of constriction of said membrane valve.
8. The device of claim 6 , wherein said device comprises at least two droplet generators, or at least 4 droplet generators.
9. The device of claim 8 , wherein a plurality of droplet generators are configured to share a common second microfluidic channel and to inject droplets into said common second microfluidic channel.
10. The device of claim 9 , wherein a droplet merger component is disposed to receive and merge droplets from said common second microfluidic channel.
11. A method of combining droplets in a microfluidic system, said method comprising providing a plurality of droplets flowing through a microfluidic channel into the central channel(s) of one or more droplet merger components according to claim 1 causing the merger of a plurality of droplets.
12. The method of claim 11 , wherein said method comprises varying the constriction created by said lateral membrane valve to control the timing of droplet merger and/or the number of merged droplets.