Emulsion compositions and methods of their use
Emulsion compositions are provided herein. Also provided herein are kits containing one or more emulsion compositions or components for making such emulsion compositions. Also provided herein are methods of using such emulsion compositions, such as for amplification of target nucleic acids in emulsion droplets.
1. An emulsion comprising water-in-oil emulsion droplets,
the droplets comprising:
water;
a plurality of cyclodextrin molecules; and
a plurality of amphiphilic polymer molecules, wherein individual amphiphilic polymer molecules of the plurality comprise a hydrophobic moiety and a hydrophilic moiety,
wherein at least a portion of the cyclodextrin molecules and the amphiphilic polymer molecules that form a thermally-reversible hydrogel that is in sol form at at least one temperature between 0-70° C., wherein the thermally-reversible hydrogel comprises a plurality of polypseudorotaxane complexes,
wherein a mass ratio of cyclodextrin molecules to amphiphilic polymer molecules in the droplets is from about 1:4 to about 4:1, and
wherein the droplets are present in a continuous oil phase, and wherein the emulsion lacks a cross-linkable protein that stabilizes the emulsion droplets.
2. The emulsion of claim 1 , wherein individual cyclodextrin molecules of the plurality are independently selected from the group consisting of:
an α-cyclodextrin, and a β-cyclodextrin; or
an α-cyclodextrin, and a γ-cyclodextrin; or
a β-cyclodextrin, and a γ-cyclodextrin.
3. The emulsion of claim 1 , wherein individual cyclodextrin molecules of the plurality are independently a compound of Formula I:
wherein:
each R1 is independently selected from the group consisting of a hydrophobic group, a sulfite, and H, where the hydrophobic group is selected from alkyl, alkenyl, alkynyl, haloalkyl, cycloalkyl, aryl, and any combination thereof, and the sulfite is a (C1-C6-alkyl or alkylene)-SO3- group; and
n is 6, 7, or 8.
4. The emulsion of claim 1 , wherein the amphiphilic polymer molecules comprise block co-polymers, wherein the block co-polymers comprise a hydrophilic block and a hydrophobic block.
5. The emulsion of claim 4 , wherein the block co-polymers are di-block co-polymers or tri-block co-polymers, or a combination thereof.
6. The emulsion of claim 5 , wherein the block co-polymers are di-block co-polymers comprising a polyethylene glycol (PEG) hydrophilic block and a hydrophobic block.
7. The emulsion of claim 5 , wherein the block co-polymers are di-block co-polymers comprising a hydrophilic block and a hydrophobic block comprising polypropylene glycol.
8. The emulsion of claim 5 , wherein the block co-polymers are tri-block co-polymers.
9. The emulsion of claim 8 , wherein the tri-block co-polymers are poloxamers.
10. The emulsion of claim 9 , wherein the poloxamers are poloxamer 188.
11. The emulsion of claim 1 , wherein the droplets further comprise a thermostable DNA-dependent DNA polymerase or an RNA-dependent DNA polymerase.
12. The emulsion of claim 1 , wherein the droplets further comprise nucleic acid.
13. The emulsion of claim 1 , wherein the droplets comprise a thermally reversible hydrogel.
14. The emulsion of claim 1 , wherein the droplets are present in a continuous fluorocarbon oil phase.
15. The emulsion of claim 14 , wherein the continuous fluorocarbon oil phase comprises a fluorous oil and a surfactant.
16. The emulsion of claim 15 , wherein the surfactant is a fluorosurfactant.
17. The emulsion of claim 16 , wherein the fluorosurfactant is a block co-polymer comprising a perfluorinated polyether block and a polyethylene glycol block.
18. A method of forming an emulsion according to claim 1 , the method comprising:
combining a continuous oil phase, an aqueous solution, a plurality of cyclodextrin molecules, and a plurality of amphiphilic polymer molecules, under conditions wherein at least a portion of the cyclodextrin molecules and the amphiphilic polymer molecules form a plurality of polypseudorotaxane complexes, thereby forming an emulsion comprising water-in-oil emulsion droplets.
19. A method of using an emulsion comprising a water-in-oil emulsion droplets, the method comprising:
providing the emulsion according to claim 1 ;
heating the droplets to a temperature of between about 50° C. to about 100° C.;
cooling the droplets to a temperature below about 50° C.; and
optionally repeating the heating and cooling between 1-50 times.
20. The emulsion of claim 1 , the droplets consisting of:
water;
the plurality of cyclodextrin molecules; and
the plurality of amphiphilic polymer molecules,
wherein at least a portion of the cyclodextrin molecules and the amphiphilic polymer molecules form a plurality of polypseudorotaxane complexes, and
optionally a thermostable DNA-dependent DNA polymerase, an RNA-dependent DNA polymerase, a nucleic acid, nucleotide triphosphates (NTPs), deoxyribonucleotide triphosphates (dNTPs), a buffer, a salt, a divalent cation, a fluorescent dye, a fluorescent dye-labeled nucleic acid or a combination thereof.