System for mixing fluids by coalescence of multiple emulsions

1. A method of sample analysis, comprising:

forming a first type and a second type of reagent droplets, wherein the first type has a first code and the second type has a second code to identify each type;

encapsulating the first and second types of reagent droplets in sample droplets; and

inducing fusion of the sample droplets with the encapsulated first and second types of reagent droplets to produce fused droplets each having the first code or the second code.

2. The method of claim 1 , wherein the first type and the second type of reagent droplets respectively contain a first pair of primers for amplification of a first nucleic acid target and a second pair of primers for amplification of a second nucleic acid target, and wherein the sample droplets contain nucleic acid.

3. The method of claim 1 , wherein each code is provided by at least one particle in each type of reagent droplet.

4. The method of claim 1 , wherein the step of inducing fusion includes a step of heating the first and second types of reagent droplets and the sample droplets after the step of encapsulating.

5. The method of claim 1 , wherein the step of inducing fusion includes a step of applying an electric field to the first and second types of reagent droplets and the sample droplets after the step of encapsulating.

6. The method of claim 2 , wherein the fused droplets contain a respective probe for each nucleic acid target and a thermostable polymerase, further comprising a step of thermally cycling the fused droplets after the step of inducing fusion.

7. The method of claim 6 , further comprising a step of collecting data from a label of each respective probe after the step of thermally cycling.

8. The method of claim 7 , wherein the step of collecting data includes a step of detecting fluorescence from the label of each respective probe present in a plurality of the fused droplets.

9. The method of claim 7 , further comprising a step of determining a concentration of each nucleic acid target using the collected data.

10. The method of claim 7 , wherein the step of collecting data includes a step of detecting test signals, further comprising (a) a step of detecting code signals from the fused droplets and (b) a step of utilizing the code signals to correlate test signals with the first and second types of reagent droplets.

11. The method of claim 10 , wherein the step of utilizing the code signals includes a step of correlating test signals with a presence of the first and second nucleic acid targets in the fused droplets.

12. A method of sample analysis, comprising:

obtaining an emulsion including a plurality of outer droplets disposed in a liquid carrier phase and each encapsulating at least one inner droplet, wherein the outer droplets are sample-containing droplets and the at least one inner droplet is at least one reagent-containing droplet or wherein the outer droplets are reagent-containing droplets and the at least one inner droplet is at least one sample-containing droplet; and

heating the emulsion to induce fusion of the outer droplets with the at least one inner droplet to form fused droplets that combine sample and reagent to create assay mixtures for performing an assay.

13. The method of claim 12 , wherein the step of heating creates an amplification mixture in fused droplets, wherein the amplification mixture includes primers for amplifying a nucleic acid target, a probe for the nucleic acid target, and a polymerase, and wherein the amplification mixture is capable of amplifying the nucleic acid target, if present, in the fused droplets.

14. The method of claim 13 , further comprising a step of collecting data from a label of the probe, and a step of determining a concentration of the nucleic acid target based on the collected data.

15. The method of claim 8 , wherein the step of detecting fluorescence includes a step of detecting fluorescence test signals, further comprising (a) a step of detecting code signals from the fused droplets and (b) a step of utilizing the code signals to correlate test signals with the first and second types of reagent droplets.