Formation of bilayers of amphipathic molecules
View Patent ↗A method of forming bilayers of amphipathic molecules uses droplets of aqueous solution in a hydrophobic medium such as oil. A layer of amphipathic molecules such as a lipid is formed around the surfaces of the droplets. This may be achieved by providing the lipid in the oil and leaving the droplets for a time sufficient to form the layer. The droplets are brought into contact with one another so that a bilayer of the amphipathic molecules is formed as an interface between the contacting droplets. The bilayers may be used for a wide range of studies. The technique has numerous advantages including providing a long lifetime for the bilayers, allowing study of small volumes and allowing the construction of chains and networks of droplets with bilayers in between to study complex systems.
1. A method of forming bilayers of amphipathic molecules, comprising:
forming a plurality of droplets of aqueous solution having a volume less than 1000 nL in a hydrophobic medium with a layer of amphipathic molecules around the surfaces of the droplets;
bringing droplets into contact with one another so that a bilayer of the amphipathic molecules is formed as an interface between contacting droplets.
2. A method according to claim 1 , wherein the plurality of droplets comprises more than two droplets which are brought into contact with one another in a chain or network.
3. A method according to claim 1 , wherein at least one of the droplets of aqueous solution contains a membrane protein capable of insertion into the bilayer of amphipathic molecules.
4. A method according to claim 3 , wherein the membrane protein is a channel or a pore.
5. A method according to claim 1 , further comprising taking measurements on the droplets to perform an experiment involving a process occurring at or through the bilayer of the amphipathic molecules.
6. A method according to claim 1 , further comprising bringing electrodes into electrical contact with the droplets when the droplets are in contact with one another and taking an electrical measurement using the electrodes.
7. A method according to claim 5 , wherein the electrodes are disposed inside a hydrogel and are brought into electrical contact with the droplets by disposing the hydrogel inside a droplet.
8. A method according to claim 1 , further comprising moving the droplets when the droplets are in contact with one another to vary the area of the bilayer of the amphipathic molecules.
9. A method according to claim 1 , wherein the step of bringing droplets into contact with one another is performed by disposing an anchor having a hydrophilic outer surface inside a droplet and moving the anchor to move the droplet to bring it into contact with a static droplet.
10. A method according to claim 1 , wherein the step of bringing droplets into contact with one another is performed by disposing a droplet on a support having a hydrophobic outer surface and moving a further droplet to bring it into contact with the droplet on the support.
11. A method according to claim 10 , wherein the support is annular.
12. A method according to claim 10 , wherein the support has an anchor having a hydrophilic outer surface and the droplet is disposed on the support with the anchor inside the droplet.
13. A method according to claim 12 , wherein the anchor is made of a hydrogel.
14. A method according to claim 1 , wherein the bilayer of the amphipathic molecules has a diameter in the range from 30 μm to 1000 μm.
15. A method according to claim 1 , wherein the hydrophobic medium is an oil.
16. A method according to claim 15 , wherein the oil is a hydrocarbon.
17. A method according to claim 1 , wherein the amphipathic molecules are lipid molecules.
18. A method according to claim 1 , further comprising separating droplets which have been brought into contact with one another.
19. A method according to claim 1 , wherein said step of forming a plurality of droplets of aqueous solution with a layer of amphipathic molecules around the surfaces of the droplets comprises:
(a) forming the droplets of aqueous solution in the hydrophobic medium;
(b) before or after step (a), providing the amphipathic molecules in the hydrophobic medium;
(c) after steps (a) and (b), leaving the droplets for a time sufficient for the layer of amphipathic molecules to form.
20. A method according to claim 1 , wherein said step of forming a plurality of droplets of aqueous solution with a layer of amphipathic molecules around the surfaces of the droplets comprises:
forming the plurality of droplets of aqueous solution in the hydrophobic medium from aqueous solution containing the amphipathic molecules and subsequently leaving the droplets for a time sufficient for the layer of amphipathic molecules to form.
21. A method according to claim 1 , wherein the step of bringing droplets into contact with one another consists of moving droplets to bring them into contact with one another.