Microelectrode Array System With Integrated Reference Microelectrodes To Reduce Detected Electrical Noise And Improve Selectivity Of Activation

• US 20090283425A1
• Filed: 04/02/2009
• Published: 11/19/2009
• Est. Priority Date: 04/02/2008
• Status: Active Grant

• Current Assignee: University of Utah Research Foundation (State of Utah)
• Original Assignee: University of Utah Research Foundation (State of Utah)
• Inventors: Lloyd, Marcy, Normann, Richard A., Clark, Gregory Arthur, Warren, David J., Ledbetter, Noah M.
• Granted Patent: US 8,359,083 B2
• Time in Patent Office: Days
• US Class Current: 205/792
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/685 Microneedles

Abstract

A microelectrode array system used to sense physiological signals and stimulate physiological tissue to form signals is disclosed. The array includes a dielectric substrate and a two dimensional array of signal microelectrodes substantially perpendicular to and integrated on the dielectric substrate. At least one reference microelectrode is located adjacent to and integrated with the signal microelectrodes on the dielectric substrate. The reference microelectrodes are positioned on the dielectric substrate relative to the signal microelectrodes to enable a reduced level of electrical noise to be detected between the reference microelectrodes and the recording microelectrodes.

Claims

1. A microelectrode array system used to sense physiological signals and stimulate signals in a conductive complex physiological solution, comprising:

a dielectric substrate;

a two dimensional array of signal microelectrodes substantially perpendicular to and integrated on the dielectric substrate, wherein each signal microelectrode in the array has a predetermined height relative to the dielectric substrate; and

at least one reference microelectrode located adjacent to and integrated with the signal microelectrodes on the dielectric substrate, wherein the reference microelectrodes are positioned on the dielectric substrate relative to the signal microelectrodes to enable a reduced level of electrical noise to be detected between the reference microelectrodes and the signal microelectrodes.

2. The system of claim 1, wherein the signal microelectrodes are substantially coated with an insulative material to reduce the level of electrical noise received by the signal microelectrodes and have exposed tips configured to perform at least one of sensing the physiological signals and stimulating the signals in the conductive complex physiological solution.

3. The system of claim 2, wherein at least one of the reference microelectrodes are substantially free of the insulative material to enable the reference microelectrodes to have an impedance of substantially zero ohms.

4. The system of claim 1, wherein the plurality of reference microelectrodes are positioned on the dielectric substrate relative to the signal microelectrodes to provide electrical shielding to enable a reduced level of electromyogram signals detected between the signal microelectrodes and the reference microelectrodes.

5. The system of claim 1, wherein the plurality of reference microelectrodes are electrically connected in parallel to provide additional electrical shielding to the array of signal microelectrodes.

6. The system of claim 1, wherein the plurality of reference electrodes are positioned in a column adjacent the two dimensional array of signal microelectrodes to provide additional electrical shielding to the array of signal microelectrodes.

7. The system of claim 1, wherein the two dimensional array of signal microelectrodes includes rows of microelectrodes of varying height with respect to the dielectric substrate.

8. The system of claim 1, wherein the two dimensional array of signal microelectrodes includes rows of signal microelectrodes of progressively decreasing height with respect to the dielectric substrate.

9. The system of claim 8, wherein the plurality of reference microelectrodes are positioned in a column adjacent a shortest column of signal microelectrodes in the two dimensional array and the reference electrodes are substantially longer than the shortest row of signal electrodes.

10. The system of claim 9, wherein both the column of reference microelectrodes and the shortest column of signal microelectrodes, located adjacent to the column of reference microelectrodes, include a sleeve of insulative material, with the sleeve having a substantially equal height on each of the reference microelectrodes and the signal microelectrodes.

11. The system of claim 1, wherein the at least one reference microelectrode is coated with a conductive material to increase a conductivity of the reference microelectrode.

12. The system of claim 1, wherein the plurality of reference electrodes are positioned at outer corners of the two dimensional array of signal microelectrodes to provide additional electrical shielding to the array of signal microelectrodes.

13. The system of claim 1, wherein the plurality of reference microelectrodes are positioned sufficiently remote from an active stimulating electrode in the two dimensional array of signal microelectrodes to provide monopolar stimulation.

14. The system of claim 1, wherein at least one of the plurality of reference microelectrodes are positioned adjacent to an active stimulating electrode in the two dimensional array of signal microelectrodes to provide bipolar stimulation.

15. The system of claim 1, wherein the signal microelectrodes in the two dimensional array are individually electrically addressable.

16. The system of claim 15, wherein the signal microelectrodes are configured to provide selective deactivation by sending a neural signal from the signal microelectrodes to collide with and effectively cancel out an original, undesired nerve impulse.

17. A method of sensing physiological signals and stimulating signals in a complex physiological solution, comprising:

implanting an array of signal microelectrodes integrated on a dielectric substrate into a patient such that the signal microelectrodes are proximate to at least one of neural tissue and nerve tissue, said array having a plurality of reference microelectrodes integrated onto the dielectric substrate sufficient to enable a reduced level of electrical noise to be detected between the reference microelectrodes and the signal microelectrodes; and

performing at least one of sensing the physiological signals between at least one of the signal microelectrodes and at least one of the reference microelectrodes and stimulating the signals in the conductive complex physiological solution by injecting a current between the at least one signal microelectrode and the at least one reference microelectrode.

18. The method of claim 17, wherein the stimulating further comprises selectively deactivating a nerve signal by sending a neural signal from the signal microelectrodes to collide with and effectively cancel out an original, undesired nerve impulse.

19. The method of claim 17, wherein the stimulating further comprises providing monopolar stimulation by sending a signal from at least one of the signal microelectrodes located on a first side of the microelectrode array relative to a reference microelectrode located on a substantially opposite side of the microelectrode array.

20. The method of claim 17, wherein the stimulating includes at least one of bipolar and multipolar stimulation to enable various combinations of stimulation useful for focal stimulation and blocking and steering currents.