Minimally invasive splaying microfiber electrode array and methods of fabricating and implanting the same

Patent metadata

Field	Value
Publication number	US-2017007824-A1
Application number	US-201414902734-A
Country	US
Kind code	A1
Filing date	Jul 7, 2014
Priority date	Jul 5, 2013
Publication date	Jan 12, 2017
Grant date	—

Abstract

An electrode array having a splayable bundle of fibers having heat-sharpened tips. A method of manufacturing an electrode array including heat-sharpening a tip of each of a plurality of fibers; and bundling the plurality of fibers. A method of implanting an electrode array into a subject, the electrode array having a bundle of fibers, the method including exposing a target in the subject for the electrode array; and inserting the bundle of fibers into the target, where forces holding the bundle of fibers together are released during the insertion thus resulting in splaying of the fibers. An electrical connection with the fibers can be formed by a conductive material, or in high-channel count designs formed by surface mounting two-dimensional amplifier arrays to a base of a fiber array.

First claim

1 . An electrode array comprising:
a bundle of individually addressable, insulated micro-fibers with uninsulated, exposed tips, wherein the bundle of micro-fibers splay apart upon implantation.

2 .- 45 . (canceled)

46 . The electrode array of claim 1 , wherein the micro-fibers comprise carbon.

47 . The electrode array of claim 1 , wherein the micro-fibers are held together by van der Waals forces, and splay apart upon implantation.

48 . The electrode array of claim 1 , wherein the micro-fibers comprise a conductive, memoryless material having material properties amenable to splaying during implantation.

49 . The electrode of claim 1 , wherein the exposed tips are sharpened by heating.

50 . The electrode of claim 1 , wherein the exposed tips are prepared by blunt cutting or by use of a focused ion beam.

51 . The electrode array of claim 1 , wherein the tips are heat-sharpened at an air-liquid interface.

52 . The electrode array of claim 1 comprising:
a micro-channel block comprising an opening extending through the block,
wherein the micro-fibers extend through the opening.

53 . The electrode array of claim 52 , wherein the block comprises plastic or another machineable material.

54 . The electrode array of claim 52 , wherein the block is formed by a 3D printing process.

55 . The electrode array of claim 52 , wherein the block comprises:
a main body; a pair of arms extending from the main body; and a funnel suspended by the pair of arms, wherein the micro-fibers pass through the funnel.

56 . The electrode array of claim 55 , wherein the funnel comprises an aperture having a diameter in a range from 100 microns to 500 microns.

57 . The electrode array of claim 1 , wherein each of the micro-fibers has a diameter of about 3-10 microns.

58 . The electrode array of claim 57 , wherein the diameter of each electrode is about 4.5 microns.

59 . The electrode array of claim 1 , wherein the insulated micro-fibers are insulated with parylene deposited on each of the micro-fibers at a thickness of about 1-3 microns.

60 . The electrode array of claim 52 , wherein the opening is filled with a conductive material to provide electrical contact between the micro-fibers and an electrical connector.

61 . The electrode array of claim 1 , wherein the tips are heat-sharpened with a gas/oxygen torch.

62 . The electrode array of claim 61 , wherein the impedance of the heat-sharpened tips is in a range of 0.1-1.5 MΩ.

63 . The electrode array of claim 62 , wherein the average impedance is about 1.2 MΩ.

64 . The electrode array of claim 1 , wherein the bundle of micro-fibers has an overall diameter of about 26 microns for a 16-channel device, about 36 microns for a 32-channel device, and about 50 microns for a 64-channel device.

65 . The electrode array of claim 1 , wherein each of the micro-fibers has an exposed tip having a length in the range from 72 microns to 106 microns.

66 . The electrode array of claim 65 , wherein the length is about 89 microns.

67 . The electrode array of claim 1 , wherein the bundle of micro-fibers is adapted to splay during implantation into a subject.

68 . The electrode array of claim 1 , wherein the electrode array yields stable signals over a time period of greater than a week.

69 . The electrode array of claim 68 , wherein the time period is greater than a month.

70 . A method of manufacturing an electrode array comprising:
bundling a plurality of individually addressable, insulated micro-fibers; and exposing a tip of each of the plurality of insulated micro-fibers by heat-sharpening at an air-liquid interface to remove the insulation.

71 . The method of manufacturing an electrode array of claim 70 , wherein the micro-fibers comprise carbon.

72 . The method of manufacturing an electrode array of claim 70 , wherein the micro-fibers are held together by van der Waals forces, and splay apart upon implantation.

73 . The method of manufacturing an electrode array of claim 70 , wherein the micro-fibers comprise a conductive, memoryless material having material properties amenable to splaying during implant.

74 . The method of manufacturing an electrode array of claim 70 comprising:
lowering the electrode array into a liquid bath with tips of the plurality of fibers protruding above a surface of the liquid bath; and
passing a heating means over the surface of the liquid bath thus burning the plurality of fibers down to a surface of the liquid bath and forming an uninsulated, sharpened tip from each of the plurality of fibers.

75 . The method of manufacturing an electrode array of claim 70 comprising:
raising the electrode array from a liquid bath with the tips of the plurality of fibers initially pointing down into the liquid bath; and
bundling the plurality of fibers with surface tension acting on the plurality of fibers as the electrode array is removed from the liquid bath.

76 . The method of manufacturing an electrode array of claim 70 comprising:
filling the plurality of openings with a conductive material.

77 . The method of manufacturing an electrode array of claim 70 comprising:
forming a block comprising a plurality of openings through the block; and
threading each of the plurality of fibers through each of the plurality openings in the block.

78 . The method of manufacturing an electrode array of claim 77 comprising:
passing the plurality of fibers through a funnel suspended from a main body of the block in order to bundle the plurality of fibers.

79 . The method of manufacturing an electrode array of claim 74 , wherein micro-fibers of multiple lengths are prepared by holding the electrode array at an angle relative to a liquid surface during the heat-sharpening process.

80 . A method of implanting an electrode array into a subject, the electrode array comprising a splayable bundle of individually addressable, insulated micro-fibers with uninsulated, exposed tips, the method comprising:
exposing a target area in the subject for the electrode array; and inserting the bundle of micro-fibers into the target area, wherein forces holding the bundle of micro-fibers together are released during the insertion, resulting in micro-fibers splaying as they move into the target area.

81 . The method of claim 80 , wherein the micro-fibers comprise carbon.

82 . The method of claim 80 , wherein the micro-fibers are held together by van der Waals forces, and the van der Waals forces are released causing the micro-fibers to splay apart upon insertion.

83 . The method of claim 80 , wherein the micro-fibers comprise a conductive, memoryless material having material properties amenable to splaying during implant.

84 . The method of claim 80 , wherein the micro-fibers splay over a distance of about 300 μm at a depth of about 2 mm into the subject.

85 . The method of claim 80 , wherein a degree of splaying is increased by a lateral tension held in the micro-fibers during the inserting step.

86 . The method of claim 80 , wherein a degree of splaying is limited by pa

Assignees

• Univ Boston

Inventors

• Gardner Timothy James
• Liberti William
• Markowitz Jeffrey
• Guitchounts Grigori

Classifications

• A61B2562/0209

  Special features of electrodes classified in A61B5/24, A61B5/25, A61B5/283, A61B5/291, A61B5/296, A61B5/053 · CPC title

• A61B2562/125

  characterised by the manufacture of electrodes · CPC title

• A61N1/0529 Primary

  Electrodes for brain stimulation · CPC title

• A61N1/0551

  Spinal or peripheral nerve electrodes · CPC title

• A61N1/0534

  Electrodes for deep brain stimulation · CPC title