EP3057499A1 - Microélectrodes à base de diamant structuré pour des applications d'interfaçage neuronal - Google Patents
Microélectrodes à base de diamant structuré pour des applications d'interfaçage neuronalInfo
- Publication number
- EP3057499A1 EP3057499A1 EP14798989.1A EP14798989A EP3057499A1 EP 3057499 A1 EP3057499 A1 EP 3057499A1 EP 14798989 A EP14798989 A EP 14798989A EP 3057499 A1 EP3057499 A1 EP 3057499A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- layer
- diamond
- microelectrode
- tubes
- atoms
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
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- 238000004519 manufacturing process Methods 0.000 claims abstract description 34
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- 229910052751 metal Inorganic materials 0.000 claims description 37
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- 238000002161 passivation Methods 0.000 claims description 17
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- LOKCTEFSRHRXRJ-UHFFFAOYSA-I dipotassium trisodium dihydrogen phosphate hydrogen phosphate dichloride Chemical compound P(=O)(O)(O)[O-].[K+].P(=O)(O)([O-])[O-].[Na+].[Na+].[Cl-].[K+].[Cl-].[Na+] LOKCTEFSRHRXRJ-UHFFFAOYSA-I 0.000 description 2
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- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
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- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
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- HWLDNSXPUQTBOD-UHFFFAOYSA-N platinum-iridium alloy Chemical compound [Ir].[Pt] HWLDNSXPUQTBOD-UHFFFAOYSA-N 0.000 description 1
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- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
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Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/25—Bioelectric electrodes therefor
- A61B5/279—Bioelectric electrodes therefor specially adapted for particular uses
- A61B5/291—Bioelectric electrodes therefor specially adapted for particular uses for electroencephalography [EEG]
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N1/00—Electrotherapy; Circuits therefor
- A61N1/02—Details
- A61N1/04—Electrodes
- A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
- A61N1/0551—Spinal or peripheral nerve electrodes
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/12—Manufacturing methods specially adapted for producing sensors for in-vivo measurements
- A61B2562/125—Manufacturing methods specially adapted for producing sensors for in-vivo measurements characterised by the manufacture of electrodes
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/28—Electrolytic cell components
- G01N27/30—Electrodes, e.g. test electrodes; Half-cells
- G01N27/308—Electrodes, e.g. test electrodes; Half-cells at least partially made of carbon
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/28—Electrolytic cell components
- G01N27/30—Electrodes, e.g. test electrodes; Half-cells
- G01N27/327—Biochemical electrodes, e.g. electrical or mechanical details for in vitro measurements
- G01N27/3275—Sensing specific biomolecules, e.g. nucleic acid strands, based on an electrode surface reaction
- G01N27/3278—Sensing specific biomolecules, e.g. nucleic acid strands, based on an electrode surface reaction involving nanosized elements, e.g. nanogaps or nanoparticles
Definitions
- the present invention relates to microelectrodes and devices using these electrodes for neural interfacing applications as well as methods for making such electrodes and electrode devices.
- These electrodes can be used both for neurostimulation or for the recording of electrical signals called "Action Potentials" (PA).
- PA Electrosion Potentials
- one or more electrical pulses are transmitted from the electrode to the neuronal cells in contact with or near the electrode. This often involves activating a deficient neurophysiological function via an implantable medical device.
- Known examples of applications include cochlear implants, retinal implants, deep brain stimulation (Brain Stimulation), cortical implants.
- electrical signals (PA) propagating through a neural network in contact with or near the electrodes, are measured.
- the applications targeted here relate in particular to electrophysiological studies.
- the devices used in these applications are known as multi-electrode networks ME A (in English Multi Electrodes Arrays), and can study ex-vivo in the laboratory electrical activity of neurons.
- the electrodes used for neurostimulation must meet well-defined requirements.
- the material constituting the electrode must be biocompatible.
- the process of charge transfer must not generate tissue necrosis.
- the charge transfer must be done capacitively or by a reversible faradic transfer involving redox species present on the surface of the electrode. This faradic charge transfer must of course not generate toxic species, gas bubbles or a significant variation in pH.
- the charge injected from the electrode to the tissues must reach a density of typically several mC.cm -2 to be effective.
- the electrode must be robust for implantation in vivo. good mechanical strength and chemical inertness to resist aging in contact with tissue and must maintain its surface state after implantation.
- the electrodes must however have electrochemical properties close to those of the electrodes used for neurostimulation.
- they In the case of their use for neuronal recording, they must also have a low electrochemical impedance, typically less than 300 kOhms in order to obtain sufficiently large signal to noise level ratios.
- This impedance is strongly related to the diameter of the electrode.
- the evolution of these systems pushes the use of electrodes having smaller diameters in order to obtain a better spatial resolution of the neuronal activities.
- the reduction in diameter increases the impedance. To overcome this disadvantage, it is known to artificially increase the surface of the electrodes.
- a condition for obtaining both sufficiently large charge densities for stimulation and / or low enough impedances for recording is therefore to work with electrodes having a large interface capacitance.
- this charge density can be all the more important that the potential window of the electrode will be important. Indeed, the larger the potential window, the greater the load can be injected without dissociating the water present in the surrounding tissues.
- the electrode materials most frequently used for the envisaged applications such as platinum and Ptlr alloys, iridium oxide, tantalum / Ta 2 O 5 , titanium nitride and PEDOT have performances reported in the article by S. F Cogan, entitled “Neural Stimulation and Recordings Electrodes", Annu. Rev. Eng. 2008.10 / 275-309, and summarized in Table 1 below.
- Synthetic diamond that solves such a problem has also been considered as a potential electrode material for such applications. It is indeed a chemically and biologically inert material that is the current subject of many scientific research in the medical field and in particular that of implants and neuronal interrogation. So it seems very suitable for an implementation in vivo long term. It also has excellent electrochemical properties, in particular has a large potential window greater than 3 V in aqueous media potentially allowing a large charge injection without dissociation of the surrounding medium, high resistance to corrosion, as well as mechanical strength important compared to other materials used. These electrochemical properties also seem suitable for ex-vivo electrophysiological applications. Generally, diamond growth is on a substrate previously prepared to initiate growth by chemical vapor deposition in a plasma containing hydrogen and a carbon source.
- the diamond films obtained after growth generally have a columnar or nanocrystalline polycrystalline form depending on the growth conditions.
- the dopant used is generally boron which, from concentrations typically greater than 10 21 at.cm- 3, gives it a quasi-metallic conductivity with electrochemical properties that are generally the most efficient, ie boron-doped diamond or "BDD" diamond.
- BDD diamond electrode MEA devices have been proposed for applications of medical implants or microelectrode arrays for electrophysiology and are described in the article by P. Bergonzo, et al., Entitled “3d mechanically flexible diamond microelectrode arrays for eye implant applications: The medinas project" IRBM, 45 (32): 91-94, 201 1, and the article by Michael W. Varney et al. ., entitled “Polycrystalline-diamond MEMS biosensors including neural microelectrode-arrays", Biosensors, 1: 1 18-1 13, 201 1.
- BDD boron-doped polycrystalline diamond
- Phosphate Buffered Saline phosphate buffered saline
- the technical problem is to find a biocompatible microelectrode material that increases their interfacial capacity and reduces their electrochemical impedance when used for applications as mentioned above.
- the subject of the invention is a microelectrode for neural interfacing applications comprising a stack of a first substrate layer made of a first biocompatible material, a second layer of hooked material in a second material to initiate the growth of synthetic diamond crystals, and a third layer of a third electrically conductive material, comprising polycrystalline diamond doped with atoms comprised in the group consisting of boron atoms, nitrogen atoms and phosphorus atoms,
- the first, second and third layers having mutually parallel extension planes, characterized in that
- the third material is a textured material which comprises a compact, brush-shaped assembly of hollow or solid tubes, each consisting at least of a radially outer circumferential layer of doped polycrystalline diamond deposited radially by growth at high temperature , the tubes each having a first end attached to the second layer and a second free end, intended to be the active part of the electrode,
- the tubes being separated from each other by a void space at their first ends and projecting their second ends in a direction away from the first and second layers substantially normal to the extension plane of the second layer.
- the microelectrode comprises one or more of the following characteristics, taken alone or in combination:
- the tubes form a carpet in which all the tubes are substantially normal with respect to the plane of extension of the second layer and separated from one another regularly, or the tubes are grouped into bundles, separated from one another regularly and in which the second ends of the tubes of the same bundle approach or even touch;
- each tube has a length of between 500 nm and 50 ⁇ m, and each tube has a section having a substantially constant diameter along its entire length, or each tube has a variable section which decreases from its first end to its second end;
- the second material is a diamond hook material suitable for serving as diffusion barrier for a molten metal comprised in the assembly formed by nickel, cobalt, iron and alloys of nickel, iron, cobalt, and the like;
- first material is a biocompatible material capable of withstanding the growth conditions of the diamond, either electrically insulating, for example in the group formed by Si0 2 , Si 3 N 4 , quartz, glass, GaN, or electrically conductive, for example included in the group formed by Pt, Ptlr, Ti, TiN, TiPt alloys, diamond doped with boron;
- the second material is comprised of the group formed by titanium nitride TiN, undoped polycrystalline diamond, and polycrystalline diamond doped with atoms comprised in the group formed by boron atoms, the atoms of nitrogen and phosphorus atoms, preferably the boron doped polycrystalline diamond;
- the method comprises a fourth layer made of a fourth material consisting of doped polycrystalline diamond, the fourth layer covering the entire third layer at the base of the tubes forming the second material;
- the process comprises a fifth layer and a sixth layer
- the fifth layer being in a fifth metallic material, forming a plug of the electric current of the third layer through the second layer when the latter is electrically conductive and / or the fourth layer, the fifth layer being disposed on or above the first layer, either below the second layer when the latter is conducting, or in contact and at the periphery of the second and fourth layers independently of the electrical conductivity of the second layer, the fifth layer having a contact zone, forming a terminal electrical output of the microelectrode and deported from the third layer along the extension plane of the second layer,
- the sixth layer being a biocompatible layer of passivation of the fifth layer covering the whole of the fifth layer except for its contact zone forming the electrical output terminal of the microelectrode.
- the invention also relates to a multi-electrode network for neural interfacing applications comprising a plurality of at least two microelectrodes defined above, developed and etched on a common stack of layers in a distribution pattern on a surface plane.
- the invention also relates to a flexible implant for neural interfacing applications comprising:
- the invention also relates to a method for manufacturing a microelectrode for neural interfacing applications comprising the steps of
- a third step manufacture a third layer of a third electrically conductive material, comprising crystalline polycrystalline diamond doped by atoms comprised in the group consisting of boron atoms, nitrogen atoms and phosphorus atoms,
- the first, second and third layers having parallel extension planes, characterized in that
- the third material is a textured material which comprises a compact, brush-shaped assembly of hollow or solid tubes, each constituted at least by a radially outer peripheral layer, of doped polycrystalline diamond deposited radially by growth at high temperature, the tubes each having a first end attached to the second layer and a second free end, intended to be the active part of the electrode,
- the tubes being separated from each other by a void space at their first ends and projecting their second ends in a direction away from the first and second layers substantially normal to the extension plane of the second layer.
- the method of manufacturing a microelectrode comprises one or more of the following characteristics, taken alone or in combination:
- the manufacturing process comprises the steps of growing carbon nanotubes (CNTs) on and from the second layer, and then
- a sixth step depositing on the first layer (s) of undoped diamond with doped diamond-doped chemical vapor deposition by growing the doped diamond crystal until complete recovery of the carbon nanotubes and their partial etching or complete with radical hydrogen contained in the plasma;
- a fourth layer of doped polycrystalline diamond is also formed so as to cover the entire third layer at the base of the tubes forming the second material;
- the fourth step includes:
- a seventh thin-layer deposition step of a metal comprised in the group consisting of nickel, iron, cobalt, and their alloys, in particular FeNi, FeCoNi, preferably nickel on the second layer, and then
- the fifth step is implemented: or by a so-called "layer-by-layer” deposition consisting of successively depositing once or more times a layer of a positive or negative charge polyelectrolyte polymer followed by a layer of oppositely charged diamond nanoparticles, then immobilized on the carbon nanotubes by electrostatic attraction, the polymer being included in the group consisting of Poly- (daillyldimethylammonium chloride) (PDDAC), polystyrene sulfonate (PSS); or
- the sixth step is carried out by a microwave assisted chemical vapor deposition (PAVCD), or by radio wave plasma (RFCVD), or by hot filament of a gaseous mixture comprising methane, dihydrogen and trimethyl an atom comprised in the group consisting of boron atoms, nitrogen atoms and phosphorus atoms;
- PAVCD microwave assisted chemical vapor deposition
- RFCVD radio wave plasma
- hot filament of a gaseous mixture comprising methane, dihydrogen and trimethyl an atom comprised in the group consisting of boron atoms, nitrogen atoms and phosphorus atoms;
- the second material is comprised in the group formed by titanium nitride TiN, undoped polycrystalline diamond, and polycrystalline diamond doped with atoms comprised in the group consisting of boron atoms, nitrogen and phosphorus atoms, preferably boron doped polycrystalline diamond;
- the second material is doped polycrystalline diamond, and the second step is implemented first by spin coating undoped nano-diamond particles from an aqueous colloidal solution containing polyvinyl alcohol, then a plasma-assisted chemical vapor deposition containing methane, dihydrogen and trimethyl of the doping atom;
- the process comprises:
- a tenth step of deposition of a fifth layer structured by a photo-lithographic process, the fifth layer being in a fifth metallic material, forming a plug of the electric current of the third layer through the second layer when the latter is electrically conductive and / or the fourth layer, the fifth layer being disposed on the first layer, either below the second layer when the latter is conductive, or in contact and at the periphery of the second and fourth layers independently of the electrical conductivity of the second layer, the fifth layer having a contact zone, forming an electrical output terminal of the microelectrode and deported from the third layer along the extension plane of the first layer,
- the first material is a biocompatible material capable of withstanding the growth conditions of the diamond, either electrically insulating, for example comprised in the group consisting of SiO 2 , Si 3 N 4 , quartz, glass, GaN, or electrically conductive for example in the group consisting of Pt, Ptlr, Ti, TiN, TiPt alloys, diamond doped with boron.
- Figure 1 is a sectional view of a first embodiment of a microelectrode according to the invention
- Figure 2 is a sectional view of a second embodiment of a microelectrode according to the invention.
- Figure 3 is a view of the contacting of the microelectrode of Figure 1;
- Figure 4 is a view of the contacting of the microelectrode of Figure 2;
- Figures 5 and 6 are top views under a scanning electron microscope of the same forest of tubes of the active part of the microelectrodes of Figures 1 and 2 at different magnifications, respectively increasing,
- Figures 7, 8 and 9 are top views under a scanning electron microscope of the same forest of tubes of the active part of a third embodiment of a microelectrode according to the invention at different magnifications, respectively increasing ;
- Figure 10 is a general flow chart for manufacturing a microelectrode according to the invention, applicable to the manufacture of the microelectrodes of Figures 1-2 and 5-9;
- Figure 1 1 is a view of a first embodiment of a multi-electrode network of the invention through the different states of the network during its manufacture;
- Figure 12 is a view of a second embodiment of a multi-electrode network of the invention through the different states of the network during its manufacture;
- Figure 13 is a view of a third embodiment of a multi-electrode network of the invention through the various states of the network during its manufacture;
- Figure 14 is a view of a fourth embodiment of a multi-electrode network of the invention through the different states of the network during its manufacture.
- a microelectrode 2 configured for neural interfacing applications, comprises a first substrate layer 4 made of a first material, a second layer 6 hooked into a second material to initiate growth. synthetic diamond crystals, a third layer 8 of a third material, a fourth layer 10 of a fourth material, a fifth layer 12 of a fifth material, and a sixth layer 14 of a sixth material.
- the first, second, third layers 4, 6, 8 have mutually parallel extension planes.
- the fifth layer 12 is disposed here between the first layer and the second hook layer of the third layer.
- the fifth, second and third layers 12, 6, 8 share the same shape, here circular, as that of an active portion 16 of the microelectrode 2 intended to come into contact with the biological tissue.
- the fifth layer 12 forms a plug of the third layer 8 through the second layer 6.
- the fourth layer 10 has a contact zone 18, forming an electrical output terminal of the microelectrode 2 and remote from the third layer 8 along the extension plane 20 of the second layer 6.
- the sixth passivation layer 14 covers the entire fifth layer 12 with the exception of its contact zone 18 and its portion covered by the second layer 6.
- the first material is biocompatible and here electrically insulating.
- the first material is a material comprised in the group consisting of Si0 2 , Si 3 N 4 , quartz, glass, GaN, and generally any other biocompatible material capable of withstanding the growth conditions of the diamond.
- the third material electrically conductive, and constituting the active part of the microelectrode, is synthetic polycrystalline diamond, made electrically conductive by doping with atoms comprised in the group consisting of boron atoms, nitrogen atoms, and phosphorus atoms.
- the second material is boron-doped synthetic-crystalline diamond (BDD).
- the third material is also a textured material, i.e. having a structured surface, which comprises a compact brush-like assembly 22 of hollow or solid tubes 26 of nanometric to micrometric dimensions.
- the tubes 26 are each formed at least on a peripheral outer layer of poly-cristaline diamond, here doped with boron, and each have a first end 28, fixed to the second layer 6, and a second free end 30.
- the tubes 26 are separated from each other at their first ends 28 and project their second ends 30 in a direction of distance 32 from the first and second layers 4, 6, substantially vertical with respect to the extension plane 20 of the second layer 6.
- the tubes 26 form a carpet in which all the tubes are substantially vertical and separated from each other in a regular manner.
- Each tube 26 has substantially the same length, and each tube has a section having a substantially constant diameter along its entire length.
- the diamond material is chosen for the third material because it has excellent chemical inertness and high stability, as well as interesting electrochemical properties. In addition, studies show that it is bio-inert and therefore constitutes an excellent material for the realization of implantable devices.
- the second material is a material for hanging tubes 26 of the third material suitable for serving as diffusion barrier to a molten metal comprised in the assembly formed by nickel, cobalt, iron and nickel alloys, iron, cobalt .
- the second material is electrically conductive and constitutes a collector of the electric current supplied by the third layer.
- the second material when electrically conductive is titanium nitride TiN or polycrystalline diamond made electrically conductive by doping with atoms comprised in the group consisting of boron atoms, nitrogen atoms, and atoms. of phosphorus, and resulting from a conventional columnar growth from diamond grains on a smooth substrate.
- the second material is boron-doped synthetic (BDD) polycrystalline diamond derived from conventional growth on a smooth substrate.
- BDD boron-doped synthetic
- the fourth material is made of conductive doped polycrystalline diamond which covers the entire second layer at the base of the tubes forming the second material.
- the fifth material is generally one or more metals and is isolated from the electrolytic solution formed at the interface of the biological tissue by the electrically insulating sixth layer 14.
- the sixth material is a passivation material, biocompatible and electrically insulating.
- a second embodiment of the microelectrode 52 comprises the same elements as those described in the first embodiment of Figure 1 with the exception of the second layer 6 and the fifth layer 12, replaced by a different second and fifth layers, designated respectively by references 56 and 62.
- the second material of the second layer 56 is here undoped and electrically insulating polycrystalline diamond, resulting from a conventional columnar growth from diamond grains on a smooth substrate.
- the fifth metal layer 62 forms a plug of the electric current of the third layer 8 through the fourth layer 10 being disposed in contact and at the periphery of the second and fourth layers 56, 10.
- the presence of the fourth layer 10 is necessary because of the electrical conductivity defect of the second layer 56 whose functions are limited to the attachment of the tubes of the third material and the diffusion barrier to a molten metal, included in FIG. the assembly formed by nickel, cobalt, iron and alloys of nickel, iron, cobalt, and acting as a catalyst in a step of manufacturing the third material.
- the shapes seen from above of the sockets respectively formed by the fifth layers 12, 62 of the microelectrodes 2, 52 differ from each other in that the first fifth layer 12 in its current collection portion has the form of a solid disc, while the second fifth layer 52 has the shape of a ring matching and covering the contour of the second and fourth layers.
- microelectrodes 2, 52 according to the invention, described in FIGS. 1 and 2 advantageously differ from the other conventional electrodes known to those skilled in the art, for the following reasons:
- the microelectrodes 2, 52 retain a large potential window in aqueous media unlike other electrodes known to those skilled in the art, which allows to obtain significant charge densities without degrading the solvent in the environment of the electrode.
- the hybrid microelectrodes 2, 52 have a double-layer electrical capacitance typically ten to five hundred times greater than that of the conventional BDD electrodes, which allows both to increase the charge density with respect to a conventional diamond electrode and also to significantly reduce the impedance of the electrode, particularly high in the case of conventional doped diamond. (iii) Unlike conventional electrode materials used in targeted applications, microelectrodes 2, 52 are extremely robust and stable.
- microelectrodes 2, 52 composed in their active part only of inert carbon is expected to have a good acceptability of the tissues, in other words to be bio-inert, as has already been demonstrated in the case of classical unstructured doped diamond.
- the top views of the doped diamond tubes observed at different magnifications show a first arrangement of the tubes according to the first and second embodiments of FIGS. 1 and 2, ie embodiments in which the tubes 26 are substantially vertical and separated from each other in a regular manner.
- the tubes of the third layer designated respectively by the numerical reference 126 are grouped into “bundles” 128, called “bundles”, separated from each other in a regular manner and in which the second free ends 132 of the tubes 126 of the same bundle 128 approach or even touch.
- Each tube 126 has a variable section which decreases from its first end, attached to the third layer, to its second free end 132.
- the applications targeted by the invention generally consist in the use of MEA networks of microelectrodes as described above.
- the electrodes networked on the same substrate will be electrically contacted individually.
- a flexible implant for neural interfacing applications comprises an MEA network of at least two microelectrodes, developed and etched on a common layer stack in a distribution pattern on a flat surface, and an envelope matrix. .
- the matrix made of a flexible polymer material of small thickness and of two-dimensional main extension, comprises a single layer sheet, and for each microelectrode, a single and different layer with two layers enveloping the microelectrode leaving exposed the second ends of its tubes and its contact area.
- the bilayer leaflets enveloping the microelectrodes are joined in one piece by the single layer sheet, with or without a through hole.
- a method of manufacturing a microelectrode 202 for neural interfacing applications as described above generally comprises a set of steps 204, 206, 208.
- a first substrate layer made of a first biocompatible material, is provided.
- the first material is a material, either electrically insulating included in the assembly formed by S1O2, Si 3 N 4 , quartz, glass, GaN, or electrically conductive included in the assembly formed by Pt, Ptlr, Ti , TiN, TiPt alloys, boron doped diamond, and generally any other biocompatible conductive material capable of withstanding the growth temperatures of the synthetic diamond.
- the first material is supposed to be an electrical insulator.
- a second layer of a second material is deposited to initiate the growth of synthetic diamond crystals.
- the second material is comprised of TiN titanium nitride, undoped polycrystalline diamond, polycrystalline diamond doped with atoms comprised in the atomic group of boron, nitrogen atoms and phosphorus atoms and derived from conventional growth on a smooth substrate.
- the second material is boron-doped (BDD) synthetic polycrystalline diamond derived from conventional growth on a smooth substrate.
- This classic unstructured diamond layer will have a dual function. First, it will serve as a diffusion barrier for a metal catalyst used for the growth of carbon nanotubes (CNTs). Secondly, during diamond growth on the NTCs, unstructured third layer diamond and diamond pushing on the NTCs will "fuse", thus promoting better bonding of the second structured layer to the substrate.
- CNTs carbon nanotubes
- a third layer of a third, electrically conductive material is fabricated.
- the third material consists of synthetic polycrystalline diamond, made electrically conductive by doping with atoms comprised in the group consisting of boron atoms, nitrogen atoms, and phosphorus atoms.
- the third material is boron-doped synthetic-crystalline diamond (BDD).
- the third material is a textured material that includes a compact, brush-like, hollow or solid tube of nanometric to micrometric dimensions.
- the tubes consist of doped polycrystalline diamond, here doped with boron, and each have a first end, attached to the second layer, and a second free end, intended to form the active part of the microelectrode.
- the tubes are separated from each other at their first ends and project their second ends in a direction away from the first and second layers, substantially vertical with respect to the extension plane of the first layer.
- the first, second, third layers are deposited so that their extension planes are mutually parallel.
- the third material is preferably manufactured using an original method of growing the diamond on a set of carbon nanotubes, sacrificial on at least part of their individual structure.
- the third step 208 comprises the successive execution of a fourth step 210, a fifth step 212 and a sixth step 214.
- the fourth step 210 consists in growing carbon NanoTubes (NTCs), sacrificial on at least part of their individual structure, on and from the second layer. Then in the fifth step 212, one or more first layers of undoped synthetic diamond nanoparticles are deposited on each of the carbon nanotubes (CNTs). Then, in the sixth step 214, by a doped diamond-doped plasma-assisted chemical vapor deposition method, is deposited on the first undoped diamond layer (s) by growing the doped diamond crystal to with complete recovery of the carbon nanotubes and the partial or complete etching of the latter by the radical hydrogen contained in the plasma.
- NTCs carbon NanoTubes
- the fourth step 210 comprises a seventh step 216, an eighth step 218 and a ninth step 220, executed successively.
- a thin layer of a catalyst metal comprised in the assembly formed by nickel, iron, cobalt, and their alloys, especially FeNi, FeCoNi, and preferably nickel (Ni), is deposited on the second layer to obtain droplets on the substrate of nanometric size.
- a catalyst metal is used to catalyze the growth of NTCs. Since the catalyst metal tends to diffuse into the substrate during annealing or during growth of NTCs, the second layer, deposited during the second step 206, acts as a diffusion barrier. As described above, a synthetic diamond layer is preferred because it further promotes adhesion of the third structured diamond layer.
- the eighth step 218 consists of annealing the thin-layer deposited catalyst metal in the seventh step 216 to obtain nanometric-sized drops of metal regularly distributed over the second layer in a pattern corresponding to the shape of the active part of the microelectrode. .
- the growth of the carbon nanotubes (CNTs) on and from the drops of the catalyst metal is carried out by a vapor deposition method. chemical (CVD).
- the length of the CNTs may vary typically from 500 nm to 5 micrometers, and will preferably be between 1 and 2 micrometers. These NTCs will be of single-sheet or multi-sheet types.
- the CNTs may be disoriented (spaghetti-shaped) or preferably vertically aligned on the substrate.
- the fifth step 212 during which undoped diamond nanoparticles are deposited in turn on the CNTs is carried out for example according to one of the following three methods.
- a "layer-by-layer” deposition is performed consisting of successively depositing a layer of a positive or negative charge polyelectrolyte polymer followed by a layer of oppositely charged diamond nanoparticles, then immobilized on the NTCs. by electrostatic attraction.
- the polymers commonly used for this stain are Poly- (diallyldimethylammonium chloride) (PDDAC) or Polystyrene sulfonate (PSS). This stack of layers can be repeated several times in order to increase the particle density on the NTCs.
- a deposit from an "inkjet" type printing system from a colloidal solution of undoped nanodiamond is carried out.
- the NCTs can retain their original geometric appearance or agglomerate to form bundles (called “bundles").
- the sixth step 214 is carried out by a microwave assisted chemical vapor deposition (PAVCD), or by radio wave plasma (RFCVD), or by hot filament of a gaseous mixture comprising methane, dihydrogen and trimethyl ether.
- PAVCD microwave assisted chemical vapor deposition
- RFCVD radio wave plasma
- hot filament of a gaseous mixture comprising methane, dihydrogen and trimethyl ether when boron is used, under suitable conditions known to those skilled in the art. Growth of diamond doped, preferably with boron at a concentration typically between 10 21 and 5.10 21 at.cm- 3 will be continued until complete recovery and partial or complete disappearance of the NTCs which will be largely etched by hydrogen radical present in the plasma.
- the PACVD method generally consists in growing diamond grains of nanometric size (2-100 nm) on a substrate placed in a PACVD growth reactor. typically operating at 800-4000 watts in a gaseous mixture comprising at least one mixture of methane and dihydrogen with a suitable proportion. During growth the temperature of the substrate is commonly between 400 and 900 degrees Celsius.
- Diamond powder may be deposited on the substrate prior to the growth step, but there are also other possible surface treatments that can initiate diamond growth. During growth, the diamond grains will grow on the substrate in the CVD plasma until a continuous polycrystalline diamond film is obtained.
- a source of atoms included among a source of boron atoms, a source of nitrogen atoms, a source of phosphorus atoms is generally introduced into the plasma during growth, for example in the case of boron in the form of diborane or trimethylboron gas. The dissociated boron in the plasma will then be incorporated in the diamond crystal or substitute for a carbon atom in the crystal.
- An alternative of the invention will be to deposit this structured diamond layer on suitable supports to make electrodes for use in certain implantable medical devices.
- implantable electrode systems to date eg cochlear implants
- these electrodes may be, for example platinum discs, platinum iridium, etc.
- the structured diamond material, ie the third layer can be deposited on such media to increase mechanical performance, electrochemical, and biocompatibility before mounting in the implantable devices.
- the structured material obtained after diamond growth brings two important functions for the microelectrode: first of all it makes it possible to considerably increase the value of the electrical capacitance of the electrode, typically of a ratio ranging from 10 to 500. Moreover he increases the surface area of the electrode because unlike unstructured polycrystalline diamond, it has a roughness that contributes to reducing the total impedance of the electrode. Unlike other materials known to those skilled in the art, this material also has a large potential window, greater than or equal to 2.5 V in an aqueous medium, that is to say comparable to that of non-polycrystalline diamond. structure. It is also very chemically stable.
- the rough diamond in the form of a forest of diamond pillars constitutes the active part of the microelectrode.
- An electrical outlet serving as a connection between the active part of the microelectrode and an external terminal is required to be able to use the electrode correctly.
- the socket is placed either between the second layer and the substrate, or at the periphery of and in contact with the third layer and a fourth layer.
- the fourth layer is made necessary when the material of the second layer is an electrical insulator. It consists of doped polycrystalline diamond, made conductive and covers the entire third layer at the base of the tubes forming the third material.
- the material of the electrical outlet is generally made of one or more metals or metal alloy, usually gold or platinum deposited on a metal acting as a layer of hooked on the substrate, eg chromium or titanium .
- the electrical outlet is isolated from the electrolyte solution forming the interface with biological tissue, by a passivation layer made of a dielectric material such as silicon dioxide S1O2, silicon nitride Si 3 N 4, polymers such as SU8, Polyimide, Parylene.
- a passivation layer made of a dielectric material such as silicon dioxide S1O2, silicon nitride Si 3 N 4, polymers such as SU8, Polyimide, Parylene.
- the method 202 described in FIG. tenth step deposition of a fifth layer and an eleventh step of deposition of a passivation layer on the electrical outlet.
- a fifth layer structured by a photo-lithographic process into a fifth metal material, is deposited so as to form a plug of the electric current of the third layer through the second layer when the latter is electrically conductive and / or the fourth layer.
- the fifth layer is disposed on the first layer, either below the second layer when the latter is conducting, or independently of the electrical conductivity of the second layer in contact and at the periphery of the second and fourth layers.
- the fifth layer comprises a contact zone, forming an electrical output terminal of the microelectrode and offset from the third layer along the extension plane of the first layer.
- a sixth biocompatible passivation layer of the fifth layer is deposited so as to cover the entire fifth layer except for the contact area forming the electrical output terminal and the active surface of the fifth layer. 'electrode.
- a first advantage of the invention is that these hybrid electrodes retain a large potential window in aqueous media comparable to that of ordinary BDD diamond electrodes, unlike other electrodes known to those skilled in the art. This makes it possible to obtain high charge densities of the order of 0.1 mC.cm -2 to 5 mC.cm -2 (at 100 mV.s -1 ) without degrading the solvent in the environment of the electrode. .
- the electrode contrary this time to conventional electrodes BDD, the electrode has a double layer capacity typically greater than 200 pF.cm -2, that is to say, forty times greater than that of conventional BDD electrodes, which makes it possible to particular, to increase the charge density with respect to a diamond electrode.
- This high capacity coupled with a greater roughness and thus a larger surface area specificity of the electrode also contributes to significantly reduce the impedance of the electrode, particularly high in the case of unstructured diamond (poly-crystalline as output from growth reactor), by a factor of 15 to 100 according to the text ration.
- a first embodiment of a method of manufacturing a multi-electrode network MEA is described through different views each corresponding to a different phase of the state of the network in the manufacturing process.
- a silica-type glass substrate 302 referred to in English as “fused silica” is used for the manufacture of the MEA network.
- the electrodes are deposited on this electrically insulating substrate.
- Any other insulating substrate eg Si / SiO 2 or Si / Si 3 N 4, quartz, etc.
- good stability is meant a substrate that does not soften and / or deform under the effect of heat.
- nano powder On this substrate 302, a deposit of diamond particles 304 ("nano powder") of nanometric dimension is deposited.
- the nano diamond powder used will preferably be the so-called “detonation” powder, because of its small size (5 to 15 nanometers for the nano primary powder).
- the nano powder can also be obtained by grinding coarser diamond powder.
- the average diameter of interest of the nano diamond powder will typically be of the order of 1 to 100 nm.
- the heart of the nano powder is composed of sp3 hybridized carbon.
- the nano diamond powder can be used raw, or after purification in the case of the detonation powder. Here we use nano powder of average diameter 20 nm obtained by grinding.
- diamond growth is initiated in a CVD growth reactor, in a plasma containing methane, hydrogen and trimethyl boron in appropriate proportions.
- the pressure in the growth chamber is between 20 and 40 m bar.
- the plasma is maintained from a microwave power source with a power of between 2 and 4 kW.
- the temperature of the substrate is between 600 and 800 degrees Celsius.
- a boron-doped diamond-shaped polycrystalline film 306 is then obtained with a thickness of typically between 100 nm and 1000 nm.
- a structured nickel deposit 308 is made by photolithography using the method known as "lift-off" known to those skilled in the art. These nickel structures define where the structured diamond electrodes will later be.
- This layer of nickel is then "dewaxed" by a heat treatment known to those skilled in the art in order to obtain nanometric structures of nickel 310 (droplets) which will be used to catalyze the growth of a forest of carbon nanotubes (NTCs). .
- the substrate is then placed in a carbon nanotube growth reactor.
- Vertically oriented nanotubes 312 are then manufactured by a method known to those skilled in the art.
- the carbon nanotubes have a length of about 2 micrometers.
- a nanodiamond layer 314 is deposited either on the entire substrate, by the "layer-by-layer” method described above, using PDDAC as hook polymer.
- a new boron-doped diamond growth is carried out under the same conditions as above until a diamond layer of typically 500 nm is obtained on the carbon nanotubes.
- the diamond structures 316 then in the definitive form of diamond pillar forest are protected by a metal mask or by a photoresist 318 again by a lithographic photo method known to those skilled in the art.
- the unprotected diamond layer is etched by a method of ionic etching RIE (Reactive Ion Etching) until complete disappearance of the unprotected diamond layer.
- the protective mask is removed by etching.
- a metal contact socket 320 is then made on the pads.
- the taking of contacts is made from a stack of Ti / Pt layers.
- Ti is used here to promote the adhesion of Pt on the substrate.
- These deposits will be structured by lithographic photo methods known to those skilled in the art.
- a metal ring will be deposited at the periphery of the diamond electrodes to leave the center of the diamond electrode bare.
- a so-called passivation layer 322 is finally deposited on the substrate leaving an uncoated area 324 on the microelectrode and on the contacts. It is this opening 324 that defines the active area of the electrode.
- a second embodiment of a method of manufacturing a multi-electrode network MEA is described through different views each corresponding to a different phase of the state of the network in the manufacturing process.
- a glass substrate 352 of "fused silica" type is once again used for the manufacture of the MEA network.
- the microelectrodes will be deposited on this electrically insulating substrate.
- any other insulating substrate eg Si / SiO 2 or Si / Si 3 N 4 , quartz, etc.
- any other insulating substrate eg Si / SiO 2 or Si / Si 3 N 4 , quartz, etc.
- a layer 354 of TiN is deposited locally at the future location of the microelectrodes.
- a layer of nickel 356 is then dewaxed by heat treatment to obtain nano drops 358 of nickel.
- NTCs 360 is carried out from the nano drops of nickel 356 on the layer 354 of TiN until a forest 362 of NTCs of lengths between 1 and 2 micrometers.
- these diamond nanoparticles 364 are deposited locally on the NTCs 362 forests using an ink jet printing technique.
- a growth of the diamond is initiated in a CVD growth reactor, in a plasma containing methane, hydrogen and trimethyl boron in appropriate proportions.
- the pressure in the growth chamber is between 20 and 40 mbar.
- the plasma is maintained from a microwave power source with a power of between 2 and 4 kW.
- the temperature of the substrate is between 600 and 800 degrees Celsius.
- a structured boron doped diamond polycrystalline film 366 is then obtained in place of the NTCs as in the preceding example.
- a plug of metal contacts 368 is then made on the pads 364 formed by the etched layer, called second layer in Figures 1 and 2.
- the contact 368 is made from a stack of Ti / Pt layers. Ti is used here to promote the adhesion of Pt on the substrate. These deposits will be structured by lithographic photo methods known to those skilled in the art. Here a metal ring will be deposited at the periphery of the diamond electrodes to leave the center of the diamond electrode bare.
- a so-called passivation layer 372 is finally deposited on the substrate 352 and the metal contact plug 368 leaving a zone 374 not covered on the electrode and the contact socket 372. It is this opening 374 which defines the active zone of the electrode.
- a third embodiment of a method of manufacturing a network of multiple electrodes is described through different views each corresponding to a different phase of the state of the network in the manufacturing process.
- a second hook layer 502 made of BDD, a metal contact plug 504 which supports high temperatures and passivation 506 is produced.
- the whole is encapsulated in a layer 508 of sacrificial metal which supports the temperature, does not catalyze not carbon nanotubes CNTs and does not promote growth CNTs.
- a "lift-off" of nickel is carried out, followed by the growth of the carbon nanotubes NTCs and a diamond deposition deposit BDD on the carbon nanotubes NTCs.
- the sacrificial metal is removed selectively, the opening of the passivation layer having been provided during the deposition of the passivation layer to clear the remote contact areas of the contact setting.
- FIG. 14 a fourth embodiment of a method for manufacturing a network of multiple electrodes forming an implant flexible, is described through different views each corresponding to a different phase of the state of the network in the manufacturing process.
- diamond electrode bases 504 are made from a previously oxidized silicon substrate 502, diamond electrode bases 504 are made. A nickel deposit 506 is made on these bases 504 of electrodes and a nickel dewetting step is performed. The growth of the nanotubes 508 (NTCs) is achieved and these nanotubes 508 are coated with diamond nanoparticles. Boron doped diamond (BDD) growth is performed to cover all the nanotubes and sacrifice them. Then, a layer 510 of Cr / Au metal is deposited to define the tracks 512, the output terminals 514 and to make contact on the diamond electrodes 516, a single track and a single terminal being shown in FIG.
- NTCs nanotubes 508
- BDD Boron doped diamond
- nitride 518 for passivation is deposited on the substrate 502 and the engagement of the contacts 510, and opened locally to define the microelectrodes 516 and the output terminals 514. Then a polymer 520 is deposited on the front face 522 and opened locally to access the microelectrodes 516 and contact terminals or output 514. The front face 522 of the wafer is protected and an opening 524 on the rear face 526 is formed in the silicon substrate to the oxide layer 524. Then a second deposit 528 of polymer is performed on the rear face 526 open. It remains only to cut the shape of the implant, for example using a laser.
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Abstract
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FR1360074A FR3011727B1 (fr) | 2013-10-16 | 2013-10-16 | Microelectrodes a base de diamant structure pour des applications d'interfacage neuronale. |
PCT/IB2014/065305 WO2015056175A1 (fr) | 2013-10-16 | 2014-10-14 | Microélectrodes à base de diamant structuré pour des applications d'interfaçage neuronal |
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US10667709B2 (en) | 2016-05-27 | 2020-06-02 | Board Of Trustees Of Michigan State University | Hybrid diamond-polymer thin film sensors and fabrication method |
WO2019067748A1 (fr) * | 2017-09-27 | 2019-04-04 | Board Of Trustees Of Michigan State University | Microélectrode implantable tout diamant et procédé de fabrication |
FR3072565B1 (fr) | 2017-10-25 | 2019-10-11 | Chambre De Commerce Et D'industrie De Region Paris Ile De France | Implant souple en diamant |
CN108744268B (zh) * | 2018-03-29 | 2021-10-15 | 北京大学 | 柔性透明碳纳米管神经电极阵列在神经光电界面中的应用 |
US10898725B2 (en) * | 2018-11-26 | 2021-01-26 | International Business Machines Corporation | Integrated optogenetic device with light-emitting diodes and glass-like carbon electrodes |
CA3134573A1 (fr) | 2019-04-30 | 2020-11-05 | Sunil Bhalchandra BADWE | Charge d'alimentation en poudre alliee mecaniquement |
CA3153254A1 (fr) | 2019-11-18 | 2021-06-17 | 6K Inc. | Charges d'alimentation uniques pour poudres spheriques et leurs procedes de fabrication |
US11590568B2 (en) | 2019-12-19 | 2023-02-28 | 6K Inc. | Process for producing spheroidized powder from feedstock materials |
WO2021263273A1 (fr) | 2020-06-25 | 2021-12-30 | 6K Inc. | Structure d'alliage microcomposite |
CN116547068A (zh) | 2020-09-24 | 2023-08-04 | 6K有限公司 | 用于启动等离子体的系统、装置及方法 |
AU2021371051A1 (en) | 2020-10-30 | 2023-03-30 | 6K Inc. | Systems and methods for synthesis of spheroidized metal powders |
CN112670440B (zh) * | 2020-12-28 | 2022-09-16 | 海南大学 | 一种利用射流注射法制备微电极的方法 |
JP2024515034A (ja) | 2021-03-31 | 2024-04-04 | シックスケー インコーポレイテッド | 金属窒化物セラミックの積層造形のためのシステム及び方法 |
FR3131011A1 (fr) * | 2021-12-21 | 2023-06-23 | Thales | Fenetre optique recouverte d une electrode en diamant dope avec fonctionnalite active d elimination des salissures. |
US12040162B2 (en) | 2022-06-09 | 2024-07-16 | 6K Inc. | Plasma apparatus and methods for processing feed material utilizing an upstream swirl module and composite gas flows |
US12094688B2 (en) | 2022-08-25 | 2024-09-17 | 6K Inc. | Plasma apparatus and methods for processing feed material utilizing a powder ingress preventor (PIP) |
Family Cites Families (6)
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JP4982641B2 (ja) * | 2000-04-12 | 2012-07-25 | 株式会社林原 | 半導体層、これを用いる太陽電池、及びそれらの製造方法並びに用途 |
US7596415B2 (en) * | 2002-12-06 | 2009-09-29 | Medtronic, Inc. | Medical devices incorporating carbon nanotube material and methods of fabricating same |
DE602004023021D1 (de) * | 2003-03-03 | 2009-10-22 | Greatbatch Ltd | Beschichtungen mit geringer Polarisation für implantierbare Elektroden |
FR2933621B1 (fr) * | 2008-07-11 | 2010-09-10 | Commissariat Energie Atomique | Sonde implantable |
FR2960787B1 (fr) * | 2010-06-09 | 2012-07-27 | Commissariat Energie Atomique | Procede de fabrication d'un implant souple retinien intraoculaire a electrodes en diamant dope |
US9296183B2 (en) * | 2011-11-30 | 2016-03-29 | Corning Incorporated | Metal dewetting methods and articles produced thereby |
-
2013
- 2013-10-16 FR FR1360074A patent/FR3011727B1/fr active Active
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- 2014-10-14 EP EP14798989.1A patent/EP3057499A1/fr active Pending
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- 2014-10-14 AU AU2014335775A patent/AU2014335775A1/en not_active Abandoned
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AU2014335775A1 (en) | 2016-05-05 |
WO2015056175A1 (fr) | 2015-04-23 |
US20160287113A1 (en) | 2016-10-06 |
FR3011727A1 (fr) | 2015-04-17 |
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