Electrode systems, devices and methods

• US 8,706,183 B2
• Filed: 06/30/2008
• Issued: 04/22/2014
• Est. Priority Date: 06/28/2007
• Status: Active Grant

• Current Assignee: University of Pittsburgh of The Commonwealth System of Higher Education
• Original Assignee: University of Pittsburgh of The Commonwealth System of Higher Education
• Inventors: Sun, Mingui, Cui, Xinyan, Alba, Nicolas Alexander
• Primary Examiner(s): Lucchesi, Nicholas
• Assistant Examiner(s): HOLLOWAY, IAN KNOBEL
• Application Number:
  US12/164,692
• Publication Number:
  US 20090005667A1
• Time in Patent Office: 2,122 Days
• Field of Search: 600/397, 600/365, 602/48
• US Class Current: 600/397
• CPC Class Codes: A61B 2562/0215 Silver or silver chloride containing
• CPC Class Codes: A61B 2562/0217 Electrolyte containing
• CPC Class Codes: A61B 2562/125 characterised by the manufacture of electrodes
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/259 using conductive adhesive means, e.g. gels
• CPC Class Codes: A61B 5/291 for electroencephalography [EEG]
• CPC Class Codes: A61B 5/296 for electromyography [EMG]
• CPC Class Codes: A61N 1/0408 Use-related aspects
• CPC Class Codes: A61N 1/0472 Structure-related aspects
• CPC Class Codes: A61N 1/0484 Garment electrodes worn by the patient
• CPC Class Codes: A61N 1/0492 Patch electrodes A61N1/0412, A61N1/0428 take precedence
• CPC Class Codes: A61N 1/0496 characterised by using specific chemical compositions, e.g. hydrogel compositions, adhesives

Abstract

An electrode system include a flowable and cohesive surface contact element comprising a hydrophilic polymer swollen with an electrolyte fluid, the contact element having a Q′ ratio of at least 5 as defined by the equation

$Q^{\prime }=\frac{W_W}{W_G}$
wherein W_G is the dry weight of the hydrophilic polymer and W_W is weight of water in the sample after absorption of the electrolyte fluid comprising water and an electrolyte salt. The surface contact element can consist essentially of the hydrophilic polymer swollen by the electrolyte fluid. Another electrode system includes a contact element including a crosslinked hydrophilic polymer matrix. The contact element has a Q′ ratio of at least 5 as defined by the equation

$Q^{\prime }=\frac{W_W}{W_G}.$
The contact elements can also have a Q′ ratio of at least 6, at least 7, at least 10 or even at least 11.

Claims

1. An electrode system comprising a flowable and cohesive surface contact element comprising a hydrophilic polymer swollen with an electrolyte fluid, the contact element having a Q′

ratio of at least 5 as defined by the equation

2. The electrode system of claim 1 wherein the contact element comprises individual particles of crosslinked hydrophilic polymer swollen with electrolyte fluid.

3. The electrode system of claim 2 wherein the contact element has a Q′

ratio of at least 6.

4. The electrode system of claim 2 wherein the contact element has a Q′

ratio of at least 7.

5. The electrode system of claim 2 wherein the contact element has a Q′

ratio of at least 10.

6. The electrode system of claim 5 wherein the contact element has a Q′

ratio of at least 1.5 after drying in air at 37°

C. for 6 hours.

7. The electrode system of claim 5 wherein the contact element has a Q′

ratio of at least 2.0 after drying in air at 37°

C. for 6 hours.

8. The electrode system of claim 5 wherein the contact element has a Q′

ratio of at least 4.0 after drying in air at 37°

C. for 6 hours.

9. The electrode system of claim 2 wherein the crosslinked hydrophilic polymer comprises polyacrylate or a derivative of polyacrylate.

10. The electrode system of claim 9 wherein the polyacrylate is sodium polyacrylate, potassium polyacrylate or lithium polyacrylate.

11. The electrode system of claim 2 wherein the electrolyte fluid further comprises a penetration enhancer.

12. The electrode system of claim 11 wherein the penetration enhancer comprises urea.

13. The electrode system of claim 2 further comprising a conductive electrode element in electrical connection with the contact element.

14. The electrode system of claim 9 further comprising a conductive electrode element in electrical connection with the contact element.

15. The electrode system of claim 14 wherein the conductive element is nonpolarizable.

16. The electrode system of claim 14 wherein the conductive element comprises a silver/silver chloride probe.

17. The electrode system of claim 14 wherein the conductive element comprises a conductive polymer.

18. The electrode system of claim 17 wherein the conductive element comprises a conductive substrate coated on at least a portion thereof with a conductive polymer.

19. The electrode system of claim 13 further comprising a holder formed of a conductive material in which the contact element is at least partially positioned.

20. An electrode system comprising a contact element comprising a crosslinked hydrophilic polymer matrix, such that the contact element has a Q′

ratio of at least 5 as defined by the equation

21. The electrode system of claim 20 wherein the conductive element comprises a conductive polymer.

22. The electrode system of claim 20 wherein the conductive element comprises a conductive substrate coated on at least a portion thereof with a conductive polymer.

23. The electrode system of claim 20 wherein the electrolyte solution further comprises a penetration enhancer.

24. The electrode system of claim 23 wherein penetration enhancer comprises urea.

25. The electrode system of claim 20 further comprising a flowable and cohesive intermediate contact element, the intermediate contact element having a Q′

ratio of at least 5.

26. The electrode system of claim 25 wherein the intermediate contact element comprises individual particles of crosslinked hydrophilic polymer in which an electrolyte fluid comprising water and an electrolyte salt has been absorbed.

27. The electrode system of claim 26 wherein the intermediate contact element has a Q′

ratio of at least 6.

28. The electrode system of claim 26 wherein the intermediate contact element has a Q′

ratio of at least 7.

29. The electrode system of claim 26 wherein the intermediate contact element has a Q′

ratio of at least 10.

30. The electrode system of claim 26 wherein the crosslinked hydrophilic polymer comprises polyacrylate or a derivative of polyacrylate.

31. The electrode system of claim 30 wherein the polyacrylate is sodium polyacrylate, potassium polyacrylate or lithium polyacrylate.

32. The electrode system of claim 26 wherein the electrolyte fluid further comprises a penetration enhancer.

33. The electrode system of claim 32 wherein the penetration enhancer comprises urea.