Devices and methods using pore size modulation for detecting analytes in a fluid sample

1. A device comprising:

a polymeric separation medium that immobilizes one or more constituents of interest in the polymeric separation medium and has an increased pore size upon application of an applied stimulus,

wherein the polymeric separation medium comprises a non-labile crosslinker configured to crosslink the polymeric separation medium, and a labile crosslinker configured to crosslink the polymeric separation medium and de-crosslink upon application of the applied stimulus, wherein the labile crosslinker comprises N,N′-[(1-methylethylidene)bis(oxy-2,1-ethanediyl)]diacrylamide (DK),

wherein the polymeric separation medium comprises functional groups that covalently bond to one or more of the constituents of interest in the polymeric separation medium.

2. The device of claim 1 , wherein the molar ratio of the labile crosslinker to total crosslinker ranges from 0.5 to 0.99.

3. The device of claim 1 , wherein the polymeric separation medium has pore size that depends on total crosslinker content, % C, which is 15% C or less before application of the applied stimulus.

4. The device of claim 1 , wherein the polymeric separation medium has a pore size that depends on total crosslinker content, % C, which is 5% C or less after application of the applied stimulus.

5. The device of claim 1 , wherein the polymeric separation medium comprises a dissolvable polymer.

6. The device of claim 5 , wherein the dissolvable polymer comprises a thermoplastic polymer and a thermoset polymer.

7. The device of claim 6 , wherein the thermoplastic polymer comprises an agarose gel.

8. The device of claim 1 , wherein the polymeric separation medium comprises a swellable polymer.

9. The device of claim 1 , wherein the functional groups are light-activated functional groups.

10. The device of claim 1 , wherein the labile crosslinker is a moiety that forms bonds between monomers and/or polymers of the polymeric separation medium, wherein the bonds are disrupted upon application of the applied stimulus.

11. A system comprising: a device according to claim 1 ; and

a detector operatively coupled to the device.

12. A kit comprising: a device according claim 1 ; and

a packaging configured to contain the device.

13. The kit of claim 12 , further comprising instructions for using the device to detect an analyte in a fluid sample.

14. A method of detecting an analyte in a fluid sample, the method comprising:

introducing a fluid sample into a device comprising a polymeric separation medium that immobilizes one or more constituents of interest in the polymeric separation medium and has an increased pore size upon application of an applied stimulus, wherein the polymeric separation medium comprises a non-labile crosslinker configured to crosslink the polymeric separation medium, and a labile crosslinker configured to crosslink the polymeric separation medium and de-crosslink upon application of the applied stimulus, wherein the labile crosslinker comprises N,N′-[(1-methylethylidene)bis(oxy-2,1-ethanediyl)]diacrylamide (DK);

applying an electric field across the polymeric separation medium in a manner sufficient to separate components of the fluid sample in the polymeric separation medium to provide a separated sample;

contacting the polymeric separation medium with the applied stimulus, thereby causing the labile crosslinker to decrosslink and the separation medium to have an increased pore size; and

detecting the analyte in the separated sample.

15. The method of claim 14 , further comprising immobilizing the components in the polymeric separation medium.

16. The method of claim 14 , wherein the applied stimulus is an acid.

17. The method of claim 14 , wherein the detecting comprises labeling the analyte in the separated sample.

18. The method of claim 14 , further comprising contacting the separated sample components with one or more secondary reagents.

19. The method of claim 18 , wherein the contacting comprises use of one or more of diffusion, electrokinetic transport and hydrodynamic transport.

20. The method of claim 18 , wherein the one or more secondary reagents are selected from the group consisting of an affinity probe, a dye, an antibody, an enzyme, an enzyme substrate and a nucleic acid.

21. The method of claim 14 , wherein the labile crosslinker is a moiety that forms bonds between monomers and/or polymers of the polymeric separation medium, wherein the bonds are disrupted upon application of the applied stimulus.

22. The method of claim 14 , wherein the decrosslinking comprises cleavage of a covalent bond formed by the labile crosslinker.

23. The method of claim 14 , wherein the functional groups are light-activated functional groups.

24. The method of claim 23 , wherein the light-activated functional groups are activated by UV light.