Nested supramolecular capsules

1. A nested capsule comprising a first capsule held within a second capsule, and each of the first and second capsules has a shell that is a supramolecular cross-linked network, wherein

each shell is obtainable from the complexation of a composition comprising a host and one or more building blocks having suitable guest functionality, thereby to form a supramolecular cross-linked network, wherein the second capsule is not provided as a layer on the surface of the first capsule, and the supramolecular cross-linked network includes a non-covalent complex of the host and the one or more building blocks having suitable guest functionality.

2. The nested capsule according to claim 1 , wherein the host is selected from cucurbituril, cyclodextrin, calix[n]arene, and crown ether compounds, and the one or more building blocks having suitable guest functionality for the cucurbituril, cyclodextrin, calix[n]arene, and crown ether hosts.

3. The nested capsule according to claim 2 , wherein the host is a cucurbituril compound, and the one or more building blocks having suitable cucurbituril guest functionality.

4. The nested capsule according to claim 3 , wherein the host is CB[8].

5. The nested capsule according to claim 1 , wherein the shell of the first capsule is different to the shell of the second capsule.

6. The nested capsule according to claim 5 , wherein a building block present in the shell of the first capsule is not present in the shell of the second capsule.

7. The nested capsule according to claim 1 , wherein each capsule shell is obtainable from the complexation of (a) a composition comprising a host and (1) or (2); or (b) a composition comprising a plurality of covalently linked hosts and (1), (2) or (3), wherein:

(1) comprises a first building block covalently linked to a plurality of first guest molecules and a second building block covalently linked to a plurality of second guest molecules, wherein a first guest molecule and a second guest molecule together with the host are suitable for forming a ternary guest-host complex;

(2) comprises a first building block covalently linked to a plurality of first guest molecules and a plurality of second guest molecules, wherein a first and a second guest molecule together with the host are suitable for forming a ternary guest-host complex, optionally the composition further comprises a second building block covalently linked to one or more third guest molecules, one or more fourth guest molecules or both, wherein a third and a fourth molecule together with the host are suitable for forming a ternary guest-host complex, and/or the first and fourth molecules together with the host are suitable for forming a ternary guest-host complex, and/or the second and third molecules together with the host are suitable for forming a ternary guest-host complex;

(3) comprises a first building block covalently linked to a plurality of first guest molecules, wherein the first guest molecule together with the host are suitable for forming a binary guest-host complex.

8. The nested capsule according to claim 7 , wherein each capsule shell is obtainable from the complexation of a composition comprising a host and (1) or (2).

9. The nested capsule according to claim 1 , wherein one of the first and second capsules has a building block that is anionic, and the other of first and second capsules has a building block that is cationic.

10. The nested capsule according to claim 1 , wherein one of the first and second capsules has two anionic building blocks.

11. The nested capsule according to claim 1 , wherein one of the first and second capsules has two cationic building blocks.

12. The nested capsule according to claim 1 , wherein the each of the first and second capsules has a building block that is a polymeric molecule.

13. A nested capsule according to claim 1 , wherein the nested capsule holds an encapsulant.

14. The nested capsule according to claim 13 , wherein the first capsule holds a first encapsulant and the second capsule holds a second encapsulant.

15. The nested capsule according to claim 14 , wherein the first encapsulant is different to the second encapsulant.

16. The nested capsule according to claim 13 , wherein the nested capsule holds an encapsulant that is a biomolecule.

17. The nested capsule according to claim 16 , wherein the biomolecule has a detectable label.

18. A method of delivering an encapsulant to a location, the method comprising the steps of:

(i) providing a nested capsule according to claim 13 ;

(ii) delivering the nested capsule to a location; and

(iii) permitting release of the encapsulated encapsulant from the nested capsule at the location.

19. The method of claim 18 , wherein the encapsulant is held in the first capsule or the second capsule or both.

20. A method of delivering a plurality of encapsulants to one or more locations, the method comprising the steps of:

(i) providing a nested capsule according to claim 14 ;

(ii) delivering the nested capsule to a location;

(iii) permitting release of the second encapsulant from the second capsule at a first location; and

(iv) subsequently permitting release of the first encapsulant from the first capsule at the first location or a second location.

21. A method of delivering a plurality of encapsulants to a location, the method comprising the steps of:

(i) providing a nested capsule according to claim 14 ;

(ii) delivering the nested capsule to a location; and

(iii) permitting release of the second encapsulant from the second capsule at a first location and simultaneously permitting release of the first encapsulant from the first capsule, thereby to deliver the first and second encapsulants to the location.

22. A method of synthesis, the method comprising the steps of:

(i) providing a nested capsule according to claim 14 , wherein the first and second encapsulants are interactable;

(ii) permitting release of the first encapsulant from the first capsule into the second capsule, thereby to permit the first encapsulant to interact with the second encapsulant to yield a product; and

(iii) optionally permitting the release of the product from the second capsule.

23. A method for the preparation of a nested capsule according to claim 1 , the method comprising the steps of:

(i) providing a first capsule, wherein the first capsule has a shell that is a supramolecular cross-linked network;

(ii) encapsulating the first capsule within a shell of a second capsule, wherein the shell of the second capsule is a supramolecular cross-linked network, thereby to form a nested capsule.

24. A method for the preparation of a nested capsule according to claim 1 , the method comprising the steps of:

(i) providing a first droplet within a second droplet, wherein each of the first and second droplets has at its interface components suitable for forming a shell that is a supramolecular cross-linked network;

(ii) permitting the components of the first and the second droplet to form a supramolecular cross-linked network, thereby to form a nested capsule.

25. The nested capsule according to claim 1 , wherein each shell is a covalently cross-linked network, wherein the network is obtainable from the supramolecular cross-linked network by the ternary complexation of the composition comprising the host and one or more building blocks having suitable guest functionality, thereby to form the supramolecular cross-linked network, wherein the covalent cross-links are obtainable from the reaction of the guests held in the ternary complex.

26. A method of synthesising a nested capsule according to claim 1 , the method comprising the steps of:

(i) forming a first droplet of a first fluid in a continuous phase of a second fluid;

(ii) forming a second droplet of the second fluid in a continuous phase of a third fluid, wherein the second droplet contains the first droplet or a capsule obtained therefrom;

(iii) providing a first building block having guest functionality at the interface of the first fluid and the second fluid, and permitting the first building block to complex with a host at the interface;

(iv) providing a second building block having guest functionality at the interface of the second fluid and the third fluid, and permitting the first building block to complex with a host at the interface.