Array of microelectrodes for interfacing to neurons within fascicles

• US 9,662,229 B2
• Filed: 10/18/2016
• Issued: 05/30/2017
• Est. Priority Date: 02/06/2014
• Status: Active Grant

• Current Assignee: Charles Stark Draper Laboratory Incorporated
• Original Assignee: Charles Stark Draper Laboratory Incorporated
• Inventors: Achyuta, Anilkumar H., McLaughlin, Bryan
• Primary Examiner(s): FAIRCHILD, MALLIKA DIPAYAN
• Application Number:
  US15/296,738
• Publication Number:
  US 20170035582A1
• Time in Patent Office: 224 Days
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61F 2/5044 Designing or manufacturing processes
• CPC Class Codes: A61F 2/72 Bioelectric control, e.g. myoelectric
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/0558 Anchoring or fixation means therefor

Abstract

Methods and apparatus are disclosed for interfacing with nerve fibers, such as axons. Embodiments provide multiple micro-channels, into which individual fascicles of a nerve may be placed, one fascicle per micro-channel. Each micro-channel has an associated set of micro-wire electrodes that penetrate the fascicle in the micro-channel. The micro-wire electrodes are thinner than prior art photolithographed micro-electrode arrays. Consequently, more micro-wire electrodes may interface with a single fascicle, and each micro-wire electrode interfaces with fewer axons, than in the prior art. Multiple rows of micro-channels may be stacked to construct two-dimensional arrays of micro-channels. These embodiments thereby facilitate finer motor control in prosthetic devices, and more granular sensory feedback from prosthetic devices to central nervous systems, than is achievable in the prior art.

Claims

1. A method for fabricating an electrode array, the method comprising:

forming a bio-compatible dielectric substrate;

defining a plurality of parallel trenches in the substrate, each trench of the plurality of trenches having a longitudinal axis, an open top extending parallel to the longitudinal axis and a bottom and two parallel sides defined by the substrate and extending parallel to the longitudinal axis, each trench being at most 5 mm wide and at most 5 mm deep;

forming a bio-compatible dielectric lid having a top surface and an opposite bottom surface, the lid being attachable via the bottom surface to the substrate, such that when the lid is attached to the substrate, the lid covers each trench, such that each trench defines a hollow nerve capture volume bounded by the bottom and the two sides of the trench and by the bottom surface of the lid, the hollow nerve capture volume extending along the longitudinal axis of the trench;

forming a plurality of electrodes, each electrode of the plurality of electrodes being formed from bulk micro-wire, and each electrode of the plurality of electrodes having an electrically conductive portion at most 4 μ

m in diameter; and

driving the plurality of electrodes through the lid such that each electrode extends beyond the bottom surface of the lid, the plurality of electrodes being disposed about the lid such that, when the lid is attached to the substrate, at least ten electrodes of the plurality of electrodes extend into the nerve capture volume of each trench, wherein, prior to driving the plurality of electrodes through the lid, each electrode of the plurality of electrodes is distinct from the lid and distinct from the substrate.

2. A method according to claim 1, further comprising holding each electrode of the plurality of electrodes in place, relative to the lid, using friction between the lid and the electrode.

3. A method according to claim 1, further comprising performing a chemical modification to hold each electrode of the plurality of electrodes in place, relative to the lid.

4. A method according to claim 3, wherein performing the chemical modification comprises covalently bonding at least an outer sheath of each electrode of the plurality of electrodes to the lid.

5. A method according to claim 4, wherein covalently bonding comprises oxygen plasma bonding.

6. A method according to claim 3, wherein performing the chemical modification comprises using thiol chemistry.

7. A method for fabricating an electrode array, the method comprising:

forming a bio-compatible dielectric substrate;

defining a plurality of parallel trenches in the substrate, each trench of the plurality of trenches having a longitudinal axis, an open top extending parallel to the longitudinal axis and a bottom and two parallel sides defined by the substrate and extending parallel to the longitudinal axis, each trench being at most 5 mm wide and at most 5 mm deep;

forming a bio-compatible dielectric lid having a top surface and an opposite bottom surface, the lid being attachable via the bottom surface to the substrate, such that when the lid is attached to the substrate, the lid covers each trench, such that each trench defines a hollow nerve capture volume bounded by the bottom and the two sides of the trench and by the bottom surface of the lid, the hollow nerve capture volume extending along the longitudinal axis of the trench;

forming a plurality of electrodes, each electrode of the plurality of electrodes being formed from bulk micro-wire, and each electrode of the plurality of electrodes having an electrically conductive portion at most 4 μ

m in diameter;

driving the plurality of electrodes through the lid such that each electrode extends beyond the bottom surface of the lid, the plurality of electrodes being disposed about the lid such that, when the lid is attached to the substrate, at least ten electrodes of the plurality of electrodes extend into the nerve capture volume of each trench; and

holding each electrode of the plurality of electrodes in place, relative to the lid, using friction between the lid and the electrode.

8. A method according to claim 7, wherein, prior to driving the plurality of electrodes through the lid, each electrode of the plurality of electrodes is distinct from the lid and distinct from the substrate.

9. A method according to claim 7, further comprising performing a chemical modification to hold each electrode of the plurality of electrodes in place, relative to the lid.

10. A method according to claim 9, wherein performing the chemical modification comprises covalently bonding at least an outer sheath of each electrode of the plurality of electrodes to the lid.

11. A method according to claim 10, wherein covalently bonding comprises oxygen plasma bonding.

12. A method according to claim 9, wherein performing the chemical modification comprises using thiol chemistry.