Three-dimensional polymer networks with channels situated therein
The disclosure provides three-dimensional crosslinked polymer networks comprising one or more channels extending from the surface and/or near the surface of the network into the interior of the network, arrays comprising the networks, processes for making the networks, and uses of the networks and arrays.
1. A three-dimensional network which:
(a) is composed of a water-swellable polymer formed by cross-linking water-soluble polymer chains;
(b) is cross-linked to the surface of a rigid substrate;
(c) comprises at least 5 channels that:
(i) are bounded by the water-soluble polymer chains; and
(ii) converge at a point in the interior of the network such that the lateral distance between the channels decreases from the surface of the water-swellable polymer toward the surface of the rigid substrate; and
(d) comprises probe molecules covalently attached to the water-soluble polymer chains.
2. The three-dimensional network of claim 1 , which comprises at least 10 channels that converge at a point in the interior of the network such that the lateral distance between the channels decreases from the surface of the water-swellable polymer toward the surface of the rigid substrate.
3. The three-dimensional network of claim 1 , wherein at least a majority of channels in the network extends into the interior of the water-swellable polymer from a point that is less than 10 microns from the surface of the water-swellable polymer or extends into the interior of the water-swellable polymer from a point on the surface of the water-swellable polymer.
4. The three-dimensional network of claim 3 , wherein at least a majority of channels in the network extends into the interior of the water-swellable polymer from a point that is less than 5 microns from the surface of the water-swellable polymer or extends into the interior of the water-swellable polymer from a point on the surface of the water-swellable polymer.
5. The three-dimensional network of claim 1 , wherein at least a majority of channels in the network has a length that is at least 10% of the largest dimension of the network.
6. The three-dimensional network of claim 5 , wherein at least a majority of channels in the network has a length that is at least 20% of the largest dimension of the network.
7. The three-dimensional network of claim 1 , wherein at least a majority of channels in the network have a minimum cross-section of at least 5 times the network's mesh size.
8. The three-dimensional network of claim 7 , wherein at least a majority of the channels have a minimum cross-section of 5 to 25 times the network's mesh size.
9. The three-dimensional network of claim 7 , wherein at least a majority of channels in the network have a minimum cross-section of at least 15 times the network's mesh size.
10. The three-dimensional network of claim 1 , wherein at least at least a majority of the channels have a length that is 15% to 25% of the largest dimension of the network.
11. The three-dimensional network of claim 1 , wherein the network has in its hydrated state a mesh size of 5 to 75 nm.
12. The three-dimensional network of claim 7 , wherein the network has in its hydrated state a mesh size of 5 to 75 nm.
13. The three-dimensional network of claim 8 , wherein the network has in its hydrated state a mesh size of 5 to 75 nm.
14. The three-dimensional network of claim 9 , wherein the network has in its hydrated state a mesh size of 5 to 75 nm.
15. The three-dimensional network of claim 1 , wherein at least a majority of probe molecules are in the interior of the water-swellable polymer.
16. The three-dimensional array of claim 1 , wherein at least a majority of probe molecules adjoin a channel.
17. An array comprising a plurality of three-dimensional networks according to claim 1 , each cross-linked to a separate location on the surface of the rigid substrate.
18. The array of claim 17 , comprising at least 8 three-dimensional networks.
19. The array of claim 17 , wherein the plurality of three-dimensional networks comprises one or more three-dimensional networks comprising labeled control probe molecules covalently attached to the polymer chains.
20. The array of claim 19 , wherein the labeled control probe molecules are fluorescently labeled.
21. The array of claim 17 which can be reused at least 10 times.
22. A process for making a three-dimensional network according to claim 1 , comprising the steps of:
(a) exposing a mixture positioned on the surface of a rigid substrate to needle-shaped crystal forming conditions, said mixture comprising (i) an aqueous salt solution which is optionally a monovalent cation salt solution, (ii) a water-soluble polymer, (iii) a cross-linker, and (iv) probe molecules, thereby forming a mixture containing one or more needle-shaped salt crystals;
(b) exposing the mixture containing one or more salt crystals to cross-linking conditions, thereby forming a cross-linked polymer network containing one or more needle-shaped salt crystals; and
(c) contacting the cross-linked polymer network containing one or more salt crystals with a solvent in which the one or more salt crystals are soluble, thereby dissolving the needle-shaped salt crystals and forming one or more channels in place of the salt crystals.
23. The process of claim 22 , wherein:
(a) the needle-shaped crystal salt forming conditions comprise:
(i) dehydrating the mixture; or
(ii) cooling the mixture; and/or
(b) wherein the solvent is a water-based buffer.
24. The process of claim 22 , further comprising, prior to step (a), a step of applying the mixture to a surface of a rigid substrate.
25. The process of claim 23 , wherein the needle-shaped crystal salt forming conditions comprise heating the mixture by contacting the mixture with a gas that has a temperature which is higher than the temperature of the mixture, exposing the mixture to a vacuum, and/or reducing the humidity of the atmosphere surrounding the mixture.
26. The process of claim 25 , wherein the needle-shaped crystal salt forming conditions comprise heating the mixture by contacting the mixture with a gas that has a temperature which is higher than the temperature of the mixture.
27. The process of claim 23 , wherein the needle-shaped crystal salt forming conditions comprise cooling the mixture by contacting the mixture with a gas that has a temperature which is lower than the temperature of the mixture.
28. The process of claim 24 , wherein the mixture is applied to the surface of a rigid substrate in a volume of 100 pl to 5 nl.
29. A process for making an array, comprising (a) creating a plurality of three-dimensional networks by the process of claim 22 at discrete spots on the surface of the same substrate, and (b) cross-linking the plurality of three-dimensional networks to the surface.