A biological neuromodulation electrode and methods of making and using

Abstract

The application provides a biological nerve regulation electrode and a preparation and application method. A lead end of the electrode is fixedly connected with a lead resistance. The electrode comprises a metal wire and a biological compatible layer. The metal wire is arranged in an inner cavity of the electrode, and an outer surface of the metal wire is wrapped with the biological compatible layer. Ultrafine metal platinum and its alloy and the like are combined with a PI material to form a semi-flexible biological electrode, and multi-electrode contact stimulation can be realized. The electrode conductivity can be adjusted according to practical purposes, and the generation of local scars of nerve tissues is reduced. The PI has good insulation and solves biological rejection, and forms an electrode with good toughness together with the metal wire and the like. The preparation process technology is simple and easy to realize.

Description

Technical Field

[0001] This invention relates to the field of bioneuromodulation technology, and particularly to a bioneuromodulation electrode and its preparation and application methods. Background Technology

[0002] Biological neuromodulation involves using physical methods to stimulate or inhibit nerve cells and the nervous system to regulate and improve biological functions. Important invasive neuromodulation techniques include deep brain stimulation (DBS) and electrocorticography (ECoG) array stimulation. DBS and ECoG have shown significant therapeutic effects in medical applications and are also used in brain-computer interfaces and brain-computer communication. DBS stimulates brain regions, thereby activating neurons deep within the brain and regulating the brain's neural activity.

[0003] Invasive biological tissue neurostimulation electrodes are typically made of platinum or alloys of platinum and other metals. Metal electrodes are usually implanted surgically after opening the skull. Pure metal electrodes are highly rigid, and the long-term contact between the rigid electrode and the soft brain tissue can cause scarring, affecting the electrode's effectiveness.

[0004] The Utah Electrode Array (UEA) and Michigan Electrode are typical examples of array electrodes. The Utah Electrode array structure offers high spatiotemporal resolution, enabling the stimulation or recording of the firing activity of individual neurons. The Michigan Electrode features multiple electrode points on each electrode post; its three-dimensional structure provides higher integration and electrode contact density, allowing for the detection and stimulation of neuronal activity at different depths, achieving stereoscopic recording. Both the Michigan and Utah Electrodes are microneedle electrodes, making them relatively brittle and prone to breakage.

[0005] The development of electronic information technology has driven technological advancements in flexible polymer films and flexible circuits. Flexible electrode probes based on polymers such as polyimide (PI) and parylene-C have been developed. After implantation, these probes can move along with nerve cells and tissue fluid, reducing tissue damage and ensuring effective nerve cell stimulation for a longer period. However, flexible film electrode materials are primarily based on circuit board technologies, requiring multi-layer thin-film electrode fabrication processes, multiple photolithography steps, and complex manufacturing processes. Summary of the Invention

[0006] To address the problems in the prior art, this application proposes a biological neuromodulation electrode, which has the advantages of multi-electrode contact stimulation, adjustable electrode conductivity according to practical purposes, reduced local scarring of nerve tissue, good insulation and biological rejection, and good toughness.

[0007] The present invention discloses a biological neural modulation electrode, comprising an electrode, wherein the lead end of the electrode is fixedly connected to a lead resistor, the electrode comprising a metal wire and a biocompatible layer, the metal wire being disposed in the inner cavity of the electrode, and the outer surface of the metal wire being wrapped with the biocompatible layer.

[0008] In one embodiment, the electrode is made of platinum or its alloys combined with polyimide fibers. This embodiment provides the electrode with both toughness and conductivity, while also exhibiting biocompatibility.

[0009] In one embodiment, the biocompatible layer is made of polyimide. This embodiment facilitates the insulation of the electrodes.

[0010] In one embodiment, an electrode hole is provided on the side of the electrode near the electrode head. This embodiment facilitates the recording of neuronal activity at different depths.

[0011] In one embodiment, the electrode includes a needle-shaped electrode and a strip electrode, with an auxiliary hole provided at one end of the strip electrode near the electrode head. This embodiment facilitates the implantation of the auxiliary device.

[0012] In one embodiment, the spacing between the metal wires is 20 micrometers to 200 micrometers. This embodiment facilitates the improvement of the electrode's conductivity.

[0013] In one embodiment, the coating thickness of the biocompatible layer is 10 micrometers to 500 micrometers. This embodiment prevents leakage of the biocompatible layer.

[0014] This application also relates to a method for applying a biological neuromodulation electrode, which uses an electrode placement system to precisely insert and embed electrodes into nerve tissue; the electrode placement system is used to insert one or more electrodes into a single or combined implant to form a desired neural target.

[0015] This application also relates to a method for preparing a biological neural modulation electrode, comprising the following steps:

[0016] Step S1: In a clean environment, use a neutral solution to ultrasonically clean the electrode wire and then dry it with hot air;

[0017] Step S2: Use a spacing clamp to fix the electrode wire after hot air drying;

[0018] Step S3: Immerse the electrode wire in the polyimide extrusion drawing device;

[0019] Step S4: Fix the lead end of the electrode wire onto the winding mechanism;

[0020] Step S5: Heat the polyimide liquid to 350℃~450℃;

[0021] Step S6: Form a polyimide-encapsulated electrode by extrusion stretching;

[0022] Step S7: By cutting the electrode, the electrode lead end and the electrode head end are formed, and the electrode stimulation point is brought out.

[0023] In one embodiment, step S7 further includes forming a vertical three-dimensional contact point by laser drilling.

[0024] In one embodiment, step S7 further includes laser drilling in the flattened head as an auxiliary implant fixation method.

[0025] The above-mentioned technical features can be combined in various suitable ways or replaced by equivalent technical features, as long as the purpose of the present invention can be achieved.

[0026] The biological neuromodulation electrode provided by this invention has at least the following beneficial effects compared with the prior art:

[0027] 1. It has good insulation properties and can resolve biological rejection issues;

[0028] 2. Reduce the formation of local scars in nerve tissue;

[0029] 3. It has the ability to stimulate multiple electrode contacts;

[0030] 4. The electrode conductivity can be adjusted according to the intended use. Attached Figure Description

[0031] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0032] Figure 1 This shows a schematic diagram of the overall structure of a biological neuromodulation electrode according to the present invention;

[0033] Figure 2 This shows a schematic diagram of the overall structure of a biological neuromodulation electrode according to the present invention;

[0034] Figure 3 This shows a schematic diagram of the overall structure of a biological neuromodulation electrode according to the present invention;

[0035] Figure 4 This shows a schematic diagram of the overall structure of a biological neuromodulation electrode according to the present invention;

[0036] Figure 5 A schematic diagram of the fabrication process of a bio-neural modulation electrode according to the present invention is shown;

[0037] In the accompanying drawings, the same parts use the same reference numerals. The drawings are not to scale.

[0038] Figure label:

[0039] 1-Washing and drying device; 2-Spacing fixing clamp; 3-Heating device; 4-Polyimide pool; 5-Diameter measuring device; 10-Electrode; 11-Metal wire; 12-Biocompatible layer; 20-Electrode hole; 21-Auxiliary hole. Detailed Implementation

[0040] The invention will now be further described with reference to the accompanying drawings.

[0041] This invention provides a biological neuromodulation electrode, such as Figure 1 As shown, it includes an electrode 10, characterized in that the lead end of the electrode 10 is fixedly connected to a lead resistor, the electrode 10 includes a metal wire 11 and a biocompatible layer 12, the metal wire 11 is disposed in the inner cavity of the electrode 10, and the outer surface of the metal wire 11 is wrapped with the biocompatible layer 12.

[0042] In one embodiment, the electrode 10 is a combination of platinum and its alloys with polyimide fibers. Specifically, platinum is a silvery-white, lustrous metal with a melting point of 1772°C, a boiling point of 3827°C, and a density of 21.45 g / cm³ (20°C). It is relatively soft and has good ductility, thermal conductivity, and electrical conductivity. Its good ductility allows it to be drawn into very fine platinum wires and rolled into extremely thin platinum foils. This good ductility gives the electrode 10 a certain strength while allowing control over its diameter, which can be controlled between 5 and 15 micrometers. The small diameter reduces the risk of scarring caused by long-term interaction between the rigid electrode 10 and the soft brain tissue, thus improving the electrode's effectiveness. Its electrical conductivity allows the electrode 10 to detect and stimulate neuronal activity at different depths while the lead resistance is energized, thus achieving recording. The polyimide fibers provide good insulation and help prevent biological rejection, reducing damage to biological tissues and ensuring effective stimulation of nerve cells for a longer period.

[0043] In one embodiment, the biocompatible layer 12 is made of polyimide. Specifically, polyimide (PI) refers to a type of polymer containing an imide ring (-CO-N-CO-) in its main chain, and is one of the organic polymer materials with the best comprehensive performance. It has high temperature resistance up to 400℃ and a long-term operating temperature range of -200 to 300℃. Some types have no obvious melting point, high insulation performance, a dielectric constant of 4.0 at 103 Hz, and a dielectric loss of only 0.004 to 0.007, which can reduce the conductivity loss of electrode 10. Polyimide is an F to H class of insulation, preventing current loss from electrode 10 and improving the efficiency of electrode 10.

[0044] In one embodiment, an electrode hole 20 is provided on the side of the electrode 10 near the head of the electrode 10, which can be used to detect and stimulate the activity of neurons at different depths to achieve stereoscopic recording.

[0045] In one embodiment, the electrode 10 includes a needle-shaped electrode and a strip electrode. An auxiliary hole 21 is provided at one end of the strip electrode near the head of the electrode 10. Specifically, the auxiliary hole 21 can assist the implantation device in implantation, so that the electrode 10 has better adaptability.

[0046] In one embodiment, the spacing of the metal wires 11 is 20 micrometers to 200 micrometers. Specifically, the conductivity of the electrode 10 can be defined by the diameter of the metal wires 11. When using multiple electrode contacts, the spacing of the metal wires 11 is 20 micrometers, and the electrodes 10 with smaller diameters are used to prevent unstable conductivity between the electrodes 10. When the spacing of the metal wires 11 is 200 micrometers, the electrodes 10 with larger diameters are used, which can improve the conductivity of the electrodes 10. The conductivity can also be adjusted by the lead resistance. When using low conductivity, thinner metal wires 11 are used, and the lead resistance is reduced. When using high conductivity, metal wires 11 with larger diameters are used, and the lead resistance is increased. At the same time, metal wires 11 with larger diameters can carry higher conductivity.

[0047] In one embodiment, the coating thickness of the biocompatible layer 12 is 10 micrometers to 500 micrometers. Specifically, when the diameter of the metal wire 11 is 200 micrometers, the coating thickness of the biocompatible layer 12 is 500 micrometers to prevent leakage of the electrical conductivity of the metal wire 11. When the diameter of the metal wire 11 is 20 micrometers, the coating thickness of the biocompatible layer 12 is 10 micrometers, which can reduce the cost of use.

[0048] In one embodiment, a semi-flexible bioelectrode 10 is formed by combining ultrafine platinum and its alloys with PI fibers, and multi-electrode 10 contact stimulation can be achieved. The lead resistance can be adjusted according to the practical purpose. The conductivity of the electrode 10 can be adjusted by selectively using the diameter of the platinum and its alloys, etc. It can be formed into a needle-shaped electrode or a flat (strip-shaped) electrode. When performing deep implantation of the electrode 10 (DBS) (strip-shaped), a hole can be formed at the tip (implantation can be assisted by an implantation device).

[0049] In one embodiment, deep brain stimulation (DBS) stimulates brain regions, thereby activating neurons deep within the brain and regulating the activity state of brain nerves.

[0050] In one embodiment, when fabricating the ECoG array, this electrode 10 can be made into a needle shape.

[0051] In one embodiment, such as Figure 2As shown, electrode 10 can also be a flat electrode, with metal wires 11 arranged linearly and a biocompatible layer 12 wrapped around the outside of the metal wires 11.

[0052] In one embodiment, such as Figure 3 As shown, when the electrode 10 is a flat electrode, the metal wires 11 are arranged linearly, the metal wires 11 are wrapped with a biocompatible layer 12, and the head end of the metal wires 11 is provided with an electrode hole 20, which passes through the metal wires 11 and the biocompatible layer 12.

[0053] In one embodiment, such as Figure 4 As shown, when the electrode 10 is a flat electrode, the metal wires 11 are arranged linearly, the metal wires 11 are wrapped with a biocompatible layer 12, the head end of the metal wires 11 is provided with an electrode hole 20, the head end of the electrode 10 is provided with an auxiliary hole 21, and the auxiliary hole 21 passes through the metal wires 11 and the biocompatible layer 12.

[0054] In one embodiment, such as Figure 5 As shown, pure platinum wire is ultrasonically cleaned with neutral liquid, rinsed with pure water, and dried with hot air in the clean environment of cleaning and drying device 1. The wire is fixed in the spacing fixing clamp 2 (containing multiple wire electrodes). The wire is immersed in the PI extrusion drawing device. The wire is then guided to the rotary winding mechanism at the lead-out end. After being preheated by heating device 3, the wire is immersed in the PI liquid in polyimide pool 4 and heated to 350℃~450℃. Under the detection of diameter measuring device 5, the wire is extruded and drawn to form a PI-encapsulated electrode. It is then cut according to actual requirements to form head and tail lead-out electrode stimulation points (planar electrodes), or vertical longitudinal three-dimensional contacts are formed by laser drilling.

[0055] In one embodiment, an electrode placement system is used to precisely insert and embed the electrode 10 into neural tissue. The electrode placement system can be used to insert one or more electrodes into a single or combined implant to form a desired neural target. The term "implant" in this application can refer to a penetrating electrode array inserted and anchored in neural tissue, allowing the electrode position to be closer to the underlying neurons while limiting the migration of the implant relative to the neural tissue, as with non-penetrating extraneural implants. Therefore, a penetrating electrode array allows for specificity of stimulation, as individual electrode surfaces can target individual bundles and / or neural circuits. Activation of the opposite function can be avoided if appropriate groups of nerve fibers or circuits within a single bundle or specific neurons in the central nervous system are selectively targeted. The neural tissue targeted for insertion and electrode implantation can be any neural target, including but not limited to brain tissue (including cortical and / or deep brain structures), the spinal cord, and peripheral nerves. The electrode placement system utilizes oscillating vibrations within the ultrasonic frequency range to reduce the force required for insertion and implantation of the electrode array and to reduce pitting of the soft tissue being penetrated. The electrode placement system improves insertion success rates while reducing strain and trauma to the recipient's tissues.

[0056] In one embodiment, the electrode placement system includes a vibration actuator, an insertion component control unit, a translation motor, and a target stabilization component. The electrode placement system can be a desktop unit or a handheld unit. The electrode placement system can be used to insert any neural implant, including but not limited to multi-channel, single-handle devices such as modular biomimetic N-type probes; electrode arrays having multiple penetrating elements; the implant can be a fixed array anchored to the skull, bone, or other rigid material surrounding the target neural tissue, a tethered array at the end of a flexible cable anchored elsewhere, or a completely floating array. It is embedded in the target neural tissue but not fixed to any other material and can "float" within the tissue. The implant penetrating elements can be made of any biocompatible material, such as, but not limited to, tungsten, silicon, and polymers. They can have any sharp angles or shapes, such as blunt, rounded, or angled. The implant can consist of materials that transmit light to or from neural tissue, such as penetrating elements containing optical fibers, or materials that transmit fluid to or from neural tissue, such as penetrating elements containing fluid channels or dialysis membranes. The primary cause of electrode failure over time is the stiffness mismatch between the target tissue and the neural implant. For example, rigid penetrating components can damage surrounding softer tissues during mechanical movement, which in turn triggers a response in the damaged tissue. Therefore, flexible and / or ultra-thin implants (such as carbon fiber) are ideal.

[0057] In one embodiment, the electrode placement system includes a vibration actuator configured to generate vibration or oscillation to reduce the insertion force of the penetrating electrode penetrating member. The electrode penetrating member may be made of microfilaments, silicon, carbon fiber, polyimide, or parylene-based material. The vibration actuator may be an ultrasonic actuator capable of generating vibrations in the 5-20m ultrasonic range. It can operate at a resonant frequency in the 20-30kHz range, and in at least one embodiment, it may preferably operate at a resonant frequency of 25kHz. The vibration displacement output can be controlled by increasing and decreasing the drive power supplied to the vibration actuator.

[0058] In one embodiment, the vibration actuator is capable of generating vibration, preferably an axially vibrating motor. For example, the vibration actuator may be a piezoelectric multilayer actuator with a resonant frequency of 25 kHz. In other embodiments, the vibration actuator may be a voice coil motor capable of generating lower frequency vibrations, such as in the range of about 100-200 Hz, and higher displacements, such as up to several hundred micrometers.

[0059] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A biological neural modulation electrode, characterized in that, The bio-neuromodulation electrode includes an electrode wire and a biocompatible layer. The electrode wire is disposed in the inner cavity of the bio-neuromodulation electrode and includes an electrode lead end and an electrode head end. The electrode lead end is fixedly connected to a lead resistor, and the outer surface of the electrode wire has a biocompatible layer. The bio-neuromodulation electrode is made of a combination of ultrafine platinum and polyimide fibers or a platinum alloy and polyimide fibers. The biocompatible layer is made of polyimide. An electrode hole is provided on the side of the electrode near the electrode head. The bio-neuromodulation electrode is needle-shaped or strip-shaped. An auxiliary hole is provided on the end of the strip-shaped electrode near the electrode head. There are multiple electrode wires, and the spacing between the electrode wires is 20 micrometers to 200 micrometers. The coating thickness of the biocompatible layer is 10 micrometers to 500 micrometers.

2. The biological neural modulation electrode according to claim 1, characterized in that, The bio-neuromodulation electrode is a flat electrode with linearly arranged electrode wires. The electrode wires are wrapped with a biocompatible layer, and electrode holes pass through the electrode wires and the biocompatible layer.

3. The method for preparing a biological neural modulation electrode according to claim 1, characterized in that, Includes the following steps: Step S1: In a clean environment, use a neutral solution to ultrasonically clean the electrode wire and then dry it with hot air; Step S2: Use a spacing clamp to fix the electrode wire after hot air drying; Step S3: Immerse the electrode wire in the polyimide extrusion drawing device; Step S4: Fix the lead end of the electrode wire onto the winding mechanism; Step S5: Heat the polyimide liquid to 350℃~450℃; Step S6: Form a polyimide-encapsulated electrode by extrusion stretching; Step S7: Electrode lead end and electrode head end are formed by electrode cutting to bring out the electrode stimulation point; Step S7 also includes forming a vertical three-dimensional contact point by laser drilling; Step S7 also includes laser drilling in the flat head as an auxiliary implantation fixation.

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