Analyte sensors comprising hydrogel membranes
Generally, embodiments of the present disclosure relate to analyte determining methods and devices (e.g., electrochemical analyte monitoring systems) that have improved signal response and stability by inclusion of a coating including a hydrogel, a crosslinker, and a swelling modulator, where the coating is disposed proximate to a working electrode of in vivo and/or in vitro analyte sensors, e.g., continuous and/or automatic in vivo monitoring using analyte sensors and/or test strips. Also provided are systems and methods of using the, for example electrochemical, analyte sensors in analyte monitoring.
1. An electrode comprising:
a sensing layer;
a first membrane disposed over the sensing layer, wherein the first membrane is a flux limiting membrane; and
a second membrane disposed over the flux limiting membrane, wherein the second membrane is a biocompatible membrane which comprises a hydrogel, a crosslinker, and a swelling modulator comprising a 3-arm epoxide sufficient to decrease or eliminate an early signal attenuation effect by the electrode.
2. The electrode of claim 1 , wherein at least a portion of the electrode is adapted to be subcutaneously positioned in a subject.
3. The electrode of claim 1 , wherein the second membrane is configured to reduce the absorption of water as compared to a membrane in the absence of the swelling modulator.
4. The electrode of claim 1 , wherein the hydrogel comprises a heterocyclic nitrogen-containing polymer hydrogel.
5. The electrode of claim 4 , wherein the crosslinker comprises a 4-arm polyethylene glycol epoxide.
6. The electrode of claim 5 , wherein the 4-arm polyethylene glycol epoxide has a molecular weight of 1,000 to 20,000 Da.
7. The electrode of claim 1 , wherein the 3-arm epoxide comprises triglycidyl glycerol.
8. The electrode of claim 1 , wherein the hydrogel comprises a self-polymerizing hydrogel.
9. The electrode of claim 8 , wherein the self-polymerizing hydrogel comprises a polyethylene glycol hydrogel or a polyethylene glycol derivative hydrogel.
10. The electrode of claim 9 , wherein the self-polymerizing hydrogel comprises polyethylene glycol triacrylate.
11. The electrode of claim 8 , wherein the crosslinker comprises a 2-arm polyethylene glycol acrylate or a 4-arm polyethylene glycol acrylate.
12. The electrode of claim 11 , wherein the crosslinker has a molecular weight of 1,000 to 20,000 Da.
13. The electrode of claim 7 , wherein the self-polymerizing hydrogel comprises an activating agent and an initiator.
14. The electrode of claim 13 , wherein the activating agent comprises ferrous gluconate.
15. The electrode of claim 13 , wherein the initiator comprises hydrogen peroxide.
16. The electrode of claim 8 , wherein the self-polymerizing hydrogel is adapted to polymerize at room temperature.
17. The electrode of claim 1 , wherein the electrode is a glucose sensor and the sensing layer further comprises a glucose-responsive enzyme.
18. The electrode of claim 17 , wherein the sensing layer comprises a redox mediator.
19. The electrode of claim 18 , wherein the redox mediator comprises a ruthenium-containing complex or an osmium-containing complex.
20. The electrode of claim 18 , wherein the electrode is an in vivo or in vitro analyte sensor.
21. The electrode of claim 1 , wherein the crosslinker is covalently bonded to the swelling modulator.
22. The electrode of claim 21 , wherein the second membrane comprises a crosslinker having a molecular weight of 1,000 to 20,000 Da covalently bonded to a swelling modulator which does not comprise PEG.
23. The electrode of claim 1 , wherein the second membrane comprises more than one coating of the hydrogel, crosslinker and swelling modulator.
24. The electrode of claim 23 , wherein the second membrane comprises two coatings of the hydrogel, crosslinker and swelling modulator.