Systems and methods related to continuous flow droplet reaction

1. A system for detecting a biological sample, comprising:

a first injector and a second injector, wherein said first injector is configured to supply a first dispersed phase and said second injector is configured to supply a second dispersed phase;

a coalescer;

a reactor downstream of said coalescer and fluidly connected to said coalescer;

a detector; and

a controller operably connected to said first injector, said second injector and said detector, wherein said controller is configured to:

direct (i) said first dispersed phase from said first injector to said coalescer, and (ii) said second dispersed phase from said second injector to said coalescer, to yield a fluid comprising said first dispersed phase separated from said second dispersed phase by a partitioning fluid from a source, wherein said first dispersed phase or said second dispersed phase comprises said biological sample;

direct said fluid from said coalescer to said reactor downstream of said coalescer, which said fluid comprises a third dispersed phase comprising said biological sample;

in said reactor, subject said fluid to conditions sufficient to conduct a reaction on said biological sample; and

use said detector to detect said biological sample or derivative thereof.

2. The system of claim 1 , wherein said first injector or said second injector, or both, has a zero dead volume.

3. The system of claim 1 , wherein said first injector and said second injector are part of a housing, and wherein said housing is configured to move to separately bring said first injector and said second injector in fluid communication with said coalescer.

4. The system of claim 3 , wherein movement of said housing comprises rotation of said housing.

5. The system of claim 1 , wherein surfaces of said first injector or said second injector, or both, are fluorophilic.

6. The system of claim 3 , wherein surfaces of said housing are fluorophilic.

7. The system of claim 1 , wherein said partitioning fluid comprises a first continuous phase and a second continuous phase.

8. The system of claim 7 , wherein said first continuous phase, said second continuous phase, or both, comprises oil.

9. The system of claim 8 , wherein said oil is selected from fluorinated oil, silicone oil, hydrocarbon oil, or mineral oil.

10. The system of claim 7 , wherein said first continuous phase, said second continuous phase, or both, comprises a surfactant.

11. The system of claim 1 , wherein said first dispersed phase, said second dispersed phase, or both, further comprises a reagent.

12. The system of claim 1 , wherein said coalescer comprises an external source of energy.

13. The system of claim 12 , wherein said external source of energy comprises an electric field between two electrodes.

14. The system of claim 12 , wherein said external source of energy comprises a pressure source and a mechanical source.

15. The system of claim 1 , wherein said coalescer comprises a removable restriction.

16. The system of claim 15 , wherein said removable restriction comprises a gate valve, needle valve, ball valve, rotating pin, or sliding pin.

17. The system of claim 1 , wherein said controller is configured to specify at least one of a timing and volume of the first injector and the second injector.

18. The system of claim 1 , wherein said controller is configured to specify at least one of a duration and a timing of coalescing said first dispersed phase and said second dispersed phase.

19. The system of claim 1 , wherein said detector is an optical detector, wherein the optical detector is configured to detect a fluorescent signal.

20. The system of claim 1 , wherein said biological sample is a nucleic acid sample.