Microstructured arrays for cortex interaction and related methods of manufacture and use

• US 20040082875A1
• Filed: 10/24/2002
• Published: 04/29/2004
• Est. Priority Date: 10/24/2002
• Status: Active Grant

• Current Assignee: Brown University, Massachusetts Institute of Technology
• Original Assignee: Brown University, Massachusetts Institute of Technology
• Inventors: Hunter, Ian W., Martel, Sylvain, Fofonoff, Timothy A., Donoghue, John Philip, Hatsopoulos, Nicholas George, Dyer, Robert J.
• Granted Patent: US 7,212,851 B2
• Time in Patent Office: Days
• US Class Current: 600/544
• CPC Class Codes: A61B 2562/125 characterised by the manufacture of electrodes
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• 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
• CPC Class Codes: Y10T 29/49 Method of mechanical manufacture

Abstract

A brain implant system consistent with embodiments of the present invention includes an electrode array having a plurality of electrodes for sensing neuron signals. A method for manufacturing the electrode array includes machining a piece of an electrically conductive substance to create a plurality of electrodes extending from a base member. Each electrode also has a corresponding base section. A nonconductive layer is provided around at least a portion of the base section of each electrode to support the plurality of electrodes. The base section of the electrodes are then cut to separate the base member from the plurality of electrodes supported by the nonconductive support layer. The present invention also includes a complete brain implant system using the above electrode array.

Claims

1. A method of manufacturing an electrode array comprising:

machining a work piece of an electrically conductive substance to create a plurality of electrodes extending from a base member, each electrode having a corresponding base section;

providing a nonconductive layer around at least a portion of the base sections of the plurality of electrodes; and

removing the base member from the plurality of electrodes such that the plurality of electrodes are supported by the nonconductive layer.

2. The method of claim 1, wherein machining the work piece further includes:

machining the work piece to form electrodes having a platform portion where the width of the electrode is enlarged.

3. The method of claim 1, wherein machining the work piece further includes:

machining the work piece to form electrodes having a stepped pyramidal shape in which the base section of each electrode has a larger width than a tip section of each electrode.

4. The method of claim 1, wherein machining the work piece further includes applying a wire EDM technique to create the plurality of electrodes.

5. The method of claim 1, wherein the electrically conductive substance comprises at least one of stainless steel and titanium.

6. The method of claim 1, wherein the electrically conductive substance comprises a titanium-aluminum-vanadium alloy.

7. The method of claim 1, further including:

applying a chemical etching process to the machined work piece to further create the plurality of electrodes.

8. The method of claim 7, wherein the chemical etching process comprises at least one of a hydrochloric and hydrofluoric acid bath to etch the surface of the plurality of electrodes.

9. The method of claim 1, further including:

depositing a conductive material at the tips of the electrodes.

10. The method of claim 9, wherein the conductive material is at least one of gold, platinum, and titanium nitride.

11. The method of claim 1, further including:

applying an insulating layer to the plurality of electrodes, wherein the insulating layer does not cover the tips of the electrodes.

12. The method of claim 1, wherein the plurality of electrodes are held together by the nonconductive layer.

13. The method of claim 1, wherein the nonconductive layer is composed of a flexible material.

14. The method of claim 1, wherein the nonconductive layer is comprises an epoxy.

15. The method of claim 1, wherein the nonconductive layer is comprises glass.

16. The method of claim 1, wherein the nonconductive layer comprises a wiring layer.

17. The method of claim 16, wherein the wiring layer further includes a nonconductive portion and a plurality of conductors supported by the nonconductive portion, where each conductor is for connecting to a respective one of the plurality of electrodes, and wherein the nonconductive portion supports the plurality of electrodes.

18. The method of claim 17, further including:

electrically connecting the respective removed base sections of the plurality of electrodes to the respective plurality of conductors of the wiring layer.

19. The method of claim 16, wherein the wiring layer further includes a plurality of openings for respectively receiving the plurality of electrodes, wherein providing the nonconductive layer further includes:

inserting the plurality of electrodes through the respective openings of the wiring layer until the base sections of each electrode are located at the respective openings of the wiring layer.

20. The method of claim 19, wherein the openings include electrical connections connecting to a respective conductor, and wherein each electrode is connected to the respective conductor when the electrode is inserted into the opening.

21. The method of claim 16, wherein the wiring layer is composed of a flexible material.

22. The method of claim 21, wherein the flexible material comprises at least one of polyimide, parylene, and silicone.

23. The method of claim 1, wherein removing the base section further includes removing the base section using a wire EDM technique.

24. The method of claim 1, further including:

applying an epoxy coating to the nonconductive layer and to at least one of the plurality of electrodes.

25. The method of claim 1, wherein the nonconductive layer further includes a plurality of openings for respectively receiving the plurality of electrodes, wherein providing the nonconductive layer further includes:

inserting the plurality of electrodes into the respective openings of the nonconductive layer, such that the plurality of electrodes are held together by the nonconductive layer.

26. The method of claim 25, further including:

prior to removing the plurality of electrodes from the base member, securing the plurality of electrodes to the nonconductive layer with an epoxy;

27. The method of claim 25, wherein the nonconductive layer is composed of a flexible material.

28. The method of claim 1, wherein the removing of the base member occurs before the nonconductive layer is provided around the base sections of the electrodes.

29. An electrode array, comprising:

a nonconductive layer;

an array of electrodes, each electrode having a base section and a tip section, wherein the base section of each electrode is inserted into the nonconductive layer, such that the electrodes are held together by the nonconductive layer; and

an electrical connection located on the base section of each electrode to communicate with the respective electrode.

30. The array of claim 29, wherein the nonconductive layer comprises a wiring layer.

31. The array of claim 30, wherein the wiring circuit further includes a nonconductive portion and a plurality of conductors supported by the nonconductive portion and for connecting to respective ones of the plurality of electrodes, and wherein the nonconductive portion supports the plurality of electrodes.

32. The array of claim 29, wherein the nonconductive layer is comprises an epoxy.

33. The array of claim 29, wherein the nonconductive layer is comprises glass.

34. The array of claim 29, wherein the nonconductive layer comprises a flexible material.

35. The array of claim 34, wherein the flexible material comprises at least one of polyimide, parylene, and silicone.

36. The array of claim 29, wherein the electrodes are arranged in a two-dimensional matrix pattern.

37. The array of claim 29, wherein the electrodes are arranged in a honeycomb-like hexagonal pattern.

38. The array of claim 29, wherein the distances between neighboring electrodes varies.

39. The array of claim 29, wherein the electrodes increase in length from one side of the array to another side of the array.

40. The array of claim 29, wherein the plurality of electrodes have varying lengths.

41. The array of claim 40, wherein a first electrode has a length different that than of its immediately neighboring electrodes.

42. The array of claim 40, wherein the lengths of the plurality of electrodes are random.

43. The array of claim 29, wherein the plurality of electrodes have varying widths.

44. The array of claim 43, wherein a first electrode has a width different than that of each of its immediately neighboring electrodes.

45. The array of claim 29, wherein the electrodes have a platform portion where the width of the electrode is enlarged.

46. The array of claim 45, wherein the nonconductive layer rests on the platform portion of each electrode after the base section of each electrode is inserted into the nonconductive section.

47. The array of claim 29, wherein the electrodes may apply an electrical stimulation signal.

48. The array of claim 29, wherein the electrodes may detect an electrical signal.

49. A brain implant system comprising:

an electrode configured to be inserted in a brain and for sensing electrical signals generated by brain neurons;

a flexible wiring circuit connected to the electrode and adapted to receive the neuron electrical signals sensed by the electrode; and

a processing unit for receiving the neuron electrical signals from the flexible wiring circuit, wherein the processing unit further includes;

a detection module for detecting the occurrence of a neuron spike in the received neuron electrical signals; and

a transmitter for transmitting data reflecting the occurrence of each detected neuron spike.

50. The system of claim 49, wherein the detection module further includes:

means for determining whether a received neuron electrical signal exceeds a threshold level; and

means for detecting the occurrence of a neuron spike when the threshold level is exceeded.

51. The system of claim 49, wherein the electrode is part of an electrode array of a plurality of electrodes, the processing unit further includes:

an analog-to-digital converter for converting neuron electrical signals, received from the plurality of electrodes, into digital neuron data and for multiplexing the digital neuron data; and

a buffer for storing the digital neuron data after the detection module detects a neuron spike.

52. The system of claim 49, further including:

a buffer for storing digital neuron data before the detection module detects a neuron spike, and wherein contents of the buffer are overwritten when a spike is not detected.

53. The system of claim 49, wherein the transmitter is a wireless transmitter.

54. A method for operating a brain implant system, comprising:

providing an electrode configured to be inserted in a brain and for sensing electrical signals generated by brain neurons;

receiving the neuron electrical signals sensed by the electrode over a flexible wiring;

receiving the neuron electrical signals from the flexible wiring and detecting the occurrence of a neuron spike in the received neuron electrical signals; and

transmitting data reflecting the occurrence of each detected neuron spike.

55. The method of claim 54, wherein the step of detecting the occurrence of a neuron spike further includes:

determining whether a received neuron electrical signal exceeds a threshold level; and

detecting the occurrence of a neuron spike when the threshold level is exceeded.

56. The method of claim 54, wherein the electrode is part of an electrode array of a plurality of electrodes, and wherein the step of receiving the neuron electrical signals from the flexible wiring further includes:

converting neuron electrical signals, received from the plurality of electrodes, into digital neuron data and multiplexing the digital neuron data; and

storing the digital neuron data after a neuron spike is detected.

57. The method of claim 54, further including:

storing digital neuron data in a buffer before the neuron spike is detected; and

overwriting contents of the buffer when a spike is not detected.

58. The method of claim 54, further including:

wirelessly transmitting the neuron spike data.