Silicone surfactants for emulsion assays
System, including methods and compositions, for making and using emulsions that include a silicone oil and a silicone surfactant. The emulsions may include aqueous droplets disposed in a continuous phase that includes a silicone oil and a silicone surfactant. The aqueous droplets may contain an analyte, optionally at partial occupancy, and/or a luminescent (e.g., photoluminescent) reporter. An assay of the analyte may be performed with the droplets. In some cases, signals may be detected from the droplets, and a characteristic of the analyte, such as an analyte level or activity, may be determined based on the signals.
1. A method of performing an assay, the method comprising:
(A) forming an emulsion including aqueous droplets dispersed in a continuous phase, the aqueous droplets containing an analyte, the continuous phase including a silicone oil and a silicone surfactant, the silicone surfactant having the formula
the formula
or the formula
wherein
each g is independently 5-200;
each h is independently 1-5;
each i is independently 1-5;
each j is independently 15-50;
each k is independently 2-100; and
(B) detecting a signal related to the analyte from the aqueous droplets.
2. The method of claim 1 , wherein only a subset of the aqueous droplets contains the analyte.
3. The method of claim 1 , wherein the analyte is a nucleic acid.
4. The method of claim 1 , wherein the step of detecting a signal includes a step of detecting light.
5. The method of claim 4 , wherein the aqueous droplets contain a luminescent reporter, and wherein the step of detecting light includes a step of detecting light from the luminescent reporter.
6. The method of claim 5 , wherein the luminescent reporter includes a dye-labeled probe.
7. The method of claim 5 , wherein the luminescent reporter includes an intercalating dye.
8. The method of claim 1 , further comprising a step of performing an enzyme-catalyzed reaction in the aqueous droplets.
9. The method of claim 1 , wherein the silicone oil includes octamethyl trisiloxane, cyclopentasiloxane, or a trimethylsiloxysilicate at a concentration of about 0.1% to 5%.
10. The method of claim 1 , wherein the silicone oil includes one or more of octamethyl trisiloxane and polydimethylsiloxane.
11. The method of claim 1 , wherein the silicone surfactant is present in the continuous phase at a concentration of about 0.1% to 10% by weight.