Photoformed silicone sensor membrane

1. A sensing device, comprising:

a sensing surface;

a matrix overlaying the sensing surface; and

a photoformed membrane overlaying at least a portion of the matrix,

wherein the photoformed membrane comprises a directly photoformed organosiloxane polymer comprising a silsesquioxane polymer that is substantially permeable to gaseous molecules and substantially impermeable to non-gaseous molecules and ions.

2. The sensing device of claim 1 , wherein the organosiloxane polymer comprises a beta-substituted silsesquioxane polymer.

3. The sensing device of claim 1 , wherein the organosiloxane polymer comprises a hydrosilsesquioxane polymer.

4. The sensing device of claim 1 , wherein a bound moiety is displaced by exposure to light to form the photoformed membrane.

5. The sensing device of claim 4 , wherein the light comprises one or more wavelengths falling in the range of about 200 nanometers to about 400 nanometers.

6. The sensing device of claim 1 , wherein the organosiloxane polymer is crosslinked by the action of a photoinitiator.

7. The sensing device of claim 1 , wherein the photoformed membrane completely encloses the matrix.

8. The sensing device of claim 1 , wherein the photoformed membrane is patterned to provide a substantially fixed geometric relationship with the matrix.

9. The sensing device of claim 1 , wherein the photoformed membrane is patterned to provide a substantially fixed geometric relationship with the matrix and the sensing surface.

10. The sensing device of claim 1 , wherein the sensing device is configured to detect one of oxygen, carbon dioxide, and water vapor.

11. The sensing device of claim 1 , wherein the sensing device is configured to detect at least one of glucose, lactate, creatinine, ascorbate, urate, and bilirubin.

12. The sensing device of claim 1 , wherein the ions are selected from the group consisting of chloride, potassium, sodium, calcium, proton and hydroxide.

13. The sensing device of claim 1 , wherein the sensing surface is selected from the group consisting of a metal electrode, a non-metal electrode and an optical wave guide.

14. The sensing device of claim 1 , wherein the sensing surface is selected from the group consisting of platinum, gold, iridium, silver, silver halide, silver chloride and carbon.

15. The sensing device of claim 1 , wherein the sensing surface is adapted for potentiometry or amperometry.

16. The sensing device of claim 1 , wherein the matrix is selected from the group consisting of polyvinyl alcohol, photoformed polyvinyl alcohol, gelatin, photoformed gelatin and nitrocellulose.

17. The sensing device of claim 1 , wherein the matrix includes a bioactive molecule.

18. The sensing device of claim 1 , wherein the matrix includes a bioactive molecule selected from the group consisting of glucose oxidase, lactate oxidase, bilirubin oxidase, ascorbate oxidase, carbonic anhydrase, sarcosine oxidase, creatinase and creatininase.

19. The sensing device of claim 1 , wherein the matrix includes a redox species.

20. The sensing device of claim 1 , wherein the matrix includes a redox species selected form the group the group consisting of quinhydrone, a ferrocene, ferrocyanide and ferricyanide.

21. The sensing device of claim 1 , wherein the matrix includes an ion species.

22. The sensing device of claim 1 , wherein the matrix includes chloride ions.

23. A reference electrode, comprising:

a silver-silver chloride sensing surface;

a matrix containing chloride ions overlaying the sensing surface; and

a directly photoformed membrane overlaying at least a portion of the matrix,

wherein the photoformed membrane comprises an organosiloxane polymer comprising a silsesquioxane polymer that is substantially permeable to water vapor and substantially impermeable to ions, and

wherein the photoformed membrane comprises at least one orifice configured to permit exchange of ions.

24. The reference electrode of claim 23 , wherein a bound moiety is displaced by exposure to light to form the photoformed membrane.

25. The reference electrode of claim 23 , wherein the organosiloxane polymer is crosslinked by the action of a photoinitiator.

26. The reference electrode of claim 23 , wherein the photoformed membrane substantially encloses the matrix.

27. The reference electrode of claim 23 , wherein the photoformed membrane is patterned to provide a substantially fixed geometric relationship with the matrix.

28. The reference electrode of claim 23 , wherein the photoformed membrane is patterned to provide a substantially fixed geometric relationship with the matrix and the sensing surface.

29. A method of making a sensing device having a photoformed, gas-permeable membrane that is substantially impermeable to non-gaseous molecules and ions, comprising the steps of:

a.) applying an organosiloxane polymer comprising a silsesquioxane polymer having a bound labile moiety to a matrix overlaying a sensing surface to form a layer;

b.) applying ultraviolet (UV) radiation to at least a portion of the layer to remove the labile moiety and to cause the organosiloxane polymer comprising a silsesquioxane polymer to form an adhered membrane overlaying at least a portion of the matrix; and

c.) exposing the layer to a developer to selectively remove the organosiloxane polymer comprising a silsesquioxane polymer not exposed to the UV radiation.

30. A method of making a sensing device having a photoformed, gas-permeable membrane that is substantially impermeable to non-gaseous molecules and ions, comprising the steps of:

a.) applying a silsesquioxane polymer to a matrix overlaying a sensing surface to form a layer;

b.) applying ultraviolet (UV) radiation to at least a portion of the layer to cause the silsesquioxane polymer to form an adhered membrane overlaying at least a portion of the matrix; and

c.) exposing the layer to a developer to selectively remove the silsesquioxane polymer not exposed to the UV radiation.