Degradable fishbone structure flexible neural electrode and preparation method thereof

Abstract

The invention provides a degradable fishbone structure flexible neural electrode and a preparation method thereof. In the neural electrode, a degradable fishbone substrate layer is made of a degradable flexible composite material doped with a lubricant and an anti-inflammatory drug, and comprises a substrate and a plurality of rib structures; one side surface of the electrode flexible substrate layer is adhered to the fishbone base layer, and the other side surface of the electrode flexible substrate layer is provided with an electrode conductive metal layer; the conductive metal layer comprises a metal wire and electrode sites located at the end part of the metal wire, and the electrode sites are a stimulating electrode point and an acquisition electrode point; the electrode flexible packaging layer covers the conductive metal layer and exposes the electrode site area. On one hand, the fishbone-shaped structure is utilized to ensure that the electrode is stably implanted in vivo for a long time; on the other hand, the fishbone substrate layer is made of a degradable material, so that the substrate layer can be gradually degraded after being implanted for a long time, the probe can be taken out without damage, and meanwhile, a lubricant and an anti-inflammatory drug are doped in the material of the substrate layer, so that the implanting process and the taking-out process are easier.

Description

Technical Field

[0001] The present invention belongs to the field of biomedical technology, and in particular relates to a degradable fishbone structure flexible neural electrode and a method for preparing the flexible neural electrode. Background Art

[0002] As core components of brain-computer interface technology, neural probes have important applications in the diagnosis and treatment of various neurological diseases. With the development of flexible electronics, flexible neural probes with low modulus properties have gradually achieved mechanical compatibility with brain tissue, effectively reducing the risk of tissue damage during implantation. However, existing technologies lack systematic research on the safe removal of probes after long-term implantation, which has become a key bottleneck restricting their clinical translation and application.

[0003] The current technological development of neural probes presents three main directions: First, improving implant stability through structural optimization. For example, the platinum black-reinforced ultrathin probe developed by Z. Guo's team uses an anchoring structure to achieve precise implantation and has good biocompatibility. However, the mechanical interlocking effect between the anchoring structure and the newly formed glial cells will result in a large adhesion force when the probe is removed, and direct extraction can easily induce cortical laminar separation. Second, dynamic adaptation technology based on smart materials. For example, Wang S et al. developed a probe with a foldable fishbone structure design, which is inserted into brain tissue in a folded configuration to reduce tissue damage during implantation. However, it is difficult to ensure that tissue damage is reduced when the electrode is removed after long-term implantation, because the fishbone structure may undergo plastic deformation after long-term implantation and have a large rebound force when unfolded during removal. Third, the exploration of degradable material systems, such as the degradable brain electrode array with pressure sensing and its preparation method proposed in Chinese Patent 201811172002.3, in which the main electrode structure is made of degradable materials, but the non-degradability of the electrode array and pressure sensor will still remain in the body, affecting the survival of brain tissue.

[0004] Because long-term implantable electrodes need to better adhere to brain tissue and need to be firmly anchored to resist brain tissue micro-movements during long-term signal acquisition after implantation, existing implantable electrodes are often difficult to remove, which leads to the following two problems:

[0005] First, its anchoring structure is tightly interlocked with the growing brain tissue, and direct removal can easily cause tissue scratches or even fractures. This physical damage can also trigger an inflammatory response, leading to abnormal blood flow and immune cell aggregation, exacerbating nerve damage. While the nerve scars produced by injury repair provide isolation and protection, they can also hinder nerve regeneration because scar tissue can physically block the growth of nerve fibers and may release chemicals that inhibit nerve regeneration.

[0006] Second, an unremovable electrode, acting as a foreign body, will continue to irritate brain tissue, potentially triggering an immune response and forming a tissue coating on the electrode surface. This blurs the boundary between the electrode and tissue, making it difficult to accurately locate the interface during removal and increasing the risk of tissue damage during the removal process. Over time, the electrode may shift. If its position cannot be tracked, it could enter a cavity in the body, leading to serious consequences such as embolism. Summary of the Invention

[0007] The purpose of the present invention is to solve the problem of the existing technology that long-term implanted neural electrodes are difficult to remove from tissue without damage, and to provide a degradable fishbone structure flexible neural electrode and a method for preparing the flexible neural electrode. The flexible neural electrode is constructed with a degradable fishbone base layer, so that the probe can not only be firmly fixed in the tissue after implantation, meeting the needs of long-term collection; the main components of the base layer can gradually degrade over time, reducing the adverse effects of probe removal on the human body. In addition, by changing the material composition of the degradable fishbone base layer and adding lubricants and anti-inflammatory drugs, the probe can be removed with reduced removal resistance and inflammatory response, thereby greatly reducing tissue damage during the probe removal process.

[0008] To achieve the above objectives, the technical solutions provided by the present invention are:

[0009] On the one hand, a degradable fishbone structure flexible neural electrode is provided, comprising a degradable fishbone base layer, an electrode flexible substrate layer, an electrode conductive metal layer and an electrode flexible packaging layer;

[0010] The degradable fishbone base layer is made of a degradable flexible composite material doped with a lubricant and an anti-inflammatory drug, and includes a base plate and a plurality of rib structures extending parallel to both sides of the base plate in the same plane as the base plate along the length direction of the base plate;

[0011] One side surface of the electrode flexible substrate layer in the thickness direction is adhered to the degradable fishbone base layer, and the other side surface is provided with an electrode conductive metal layer;

[0012] The electrode conductive metal layer includes a metal wire and electrode sites located at the ends of the metal wire, and the electrode sites are stimulation electrode sites and collection electrode sites;

[0013] The electrode flexible packaging layer covers the electrode conductive metal layer and exposes the electrode site area.

[0014] Furthermore, the degradable fishbone base layer is made of polylactic acid-glycolic acid copolymer or polycaprolactone mixed with lubricant and anti-inflammatory drug.

[0015] Furthermore, the lubricant in the material of the degradable fishbone base layer is selected from one or more of glycerin lubricant, silicone oil lubricant and water-soluble lubricant.

[0016] Furthermore, the anti-inflammatory drug in the material of the degradable fishbone basal layer is selected from one or both of dexamethasone and compound betamethasone.

[0017] Furthermore, the electrode flexible substrate layer is made of one or more of polyimide, parylene and silica gel.

[0018] Furthermore, the thickness of the degradable fishbone base layer is 1.5 microns, and the thickness of the electrode flexible substrate layer is 6 microns.

[0019] Furthermore, the stimulation electrode points are evenly arranged along the length direction of the electrode flexible substrate layer and located in the middle in the width direction of the electrode flexible substrate layer, and the collection electrode points are located on both sides of the stimulation electrode points in the width direction of the electrode flexible substrate layer.

[0020] On the other hand, a method for preparing the above-mentioned degradable fishbone structure flexible neural electrode is provided, comprising the following steps:

[0021] Step 1: Prepare a metal sacrificial layer on the carrier of the flexible neural electrode;

[0022] Step 2: preparing a degradable flexible composite material for the degradable fishbone base layer;

[0023] Step 3: forming a degradable fishbone base layer on the metal sacrificial layer using the prepared degradable flexible composite material;

[0024] Step 4: preparing an electrode flexible substrate layer on the formed degradable fishbone base layer;

[0025] Step 5: depositing metal on the surface of the electrode flexible substrate layer and etching to obtain an electrode conductive metal layer;

[0026] Step 6: preparing an electrode flexible packaging layer on the surface of the electrode conductive metal layer, and exposing the collection electrode point area and the stimulation electrode point area on the electrode flexible packaging layer;

[0027] Step 7: Remove the sacrificial layer and complete the release of the neural electrode.

[0028] Furthermore, step 2 includes the following steps: dissolving polylactic acid-glycolic acid copolymer microspheres in chloroform to prepare a material that can degrade the fishbone basal layer.

[0029] Furthermore, in step 3, the thermal peeling tape is laser etched to produce a convex mold, and a degradable fishbone base layer is formed on the convex mold; and after step 7, the fishbone base layer and the electrode flexible substrate layer of the electrode are etched to expose the side of the stimulation electrode point opposite to the electrode flexible packaging layer, thereby preparing a double-sided electrode probe.

[0030] The advantages of the present invention are:

[0031] 1. The degradable fishbone structure flexible neural electrode proposed in the present invention has an electrode flexible substrate layer, an electrode conductive metal layer and an electrode flexible packaging layer arranged on the fishbone base layer including a substrate and a rib structure. On the one hand, the fishbone structure is used to ensure that the electrode is firmly anchored after long-term implantation in the body, reducing the influence of brain tissue micro-movement on the electrode collection and stimulation functions; on the other hand, by using degradable materials for the fishbone base layer, the base layer can be gradually degraded after long-term implantation, eliminating the anchoring effect of the rib structure of the base layer, which is conducive to the complete and intact removal of the electrode probe, and can avoid the probe itself from breaking or remaining in the tissue. At the same time, the material of the fishbone base layer is doped with lubricants and anti-inflammatory drugs, which makes the probe implantation process and the removal process after long-term implantation easier, can reduce the removal resistance, alleviate physical damage to the tissue, and reduce tissue inflammatory response.

[0032] 2. By using the degradable material polylactic acid-glycolic acid copolymer (PLGA) in the degradable fishbone base layer, the mass percentage ratio of lactide (LA) and glycolide (GA) can be controlled according to different usage requirements to change the degradation rate of the base layer. For example, when the ratio is 50:50, the complete degradation time is 1-2 months, and when the ratio is 75:25, the complete degradation time is 4-5 months, thereby improving the applicability of the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above and / or other features and advantages of the present invention will become more readily understood through the following description with reference to the accompanying drawings, which are not drawn to scale and in which some features are exaggerated or minimized to show details of particular components.

[0034] Figure 1 3D schematic diagram of a degradable fishbone structure flexible neural electrode according to an embodiment of the present invention;

[0035] Figure 2 yes Figure 1 A two-dimensional top view of the degradable fishbone structure flexible neural electrode, showing the distribution of stimulation and collection electrode points;

[0036] Figure 3 yes Figure 1 Schematic diagram of the cross section of the degradable fishbone structure flexible neural electrode in the width direction;

[0037] Figure 4 yes Figure 1 Flow chart of the preparation of degradable fishbone structure flexible neural electrodes;

[0038] Figure 5is a schematic cross-sectional view in the width direction of a degradable fishbone structure flexible neural electrode according to another embodiment of the present invention;

[0039] Figure 6 It is a schematic diagram of the implantation and removal process of the degradable fishbone structure flexible neural electrode of the present invention.

[0040] In the figure: 1-degradable fishbone base layer, 11-substrate, 12-rib structure; 2-electrode flexible substrate layer; 3-electrode conductive metal layer, 31-metal wire, 32-stimulation electrode point, 33-collection electrode point; 4-electrode flexible packaging layer. DETAILED DESCRIPTION

[0041] The present invention will be described in detail below with reference to the accompanying drawings by means of exemplary embodiments of the present invention. It should be noted that the following detailed description of the present invention is only for the purpose of illustration and is not intended to limit the present invention.

[0042] The present invention provides a degradable fishbone structure flexible neural electrode and a method for preparing the flexible neural electrode. The neural electrode probe utilizes a degradable fishbone structure and can be removed from the tissue intact while being firmly anchored in the tissue after implantation.

[0043] Reference Figure 1 The degradable fishbone structure flexible neural electrode, an exemplary embodiment of the present invention, comprises a degradable fishbone base layer 1, an electrode flexible substrate layer 2, an electrode conductive metal layer 3, and an electrode flexible encapsulation layer 4. The degradable fishbone base layer 1 stabilizes the electrode probe in tissue after implantation and partially degrades when the probe is removed, minimizing damage to the tissue during removal.

[0044] The degradable fishbone basal layer 1 comprises a base plate 11 and multiple rib structures 12 extending parallel to and in the same plane as the base plate 11 from both sides. The fishbone-shaped structure with ribs ensures stable anchoring of the electrode during long-term implantation in the body, reducing the impact of brain tissue micro-movements on the electrode's data collection and stimulation capabilities. In some embodiments, the thickness of the degradable fishbone basal layer 1 is 1.5 microns.

[0045] The degradable fishbone base layer 1 is made of a degradable flexible composite material doped with a lubricant and an anti-inflammatory drug, in particular, it is made of a PLGA copolymer doped with a lubricant and an anti-inflammatory drug, or it is made of a polycaprolactone (PCL) doped with a lubricant and an anti-inflammatory drug. The lubricant in the material of the degradable fishbone base layer 1 is selected from one or more of a glycerol lubricant, a silicone oil lubricant and a water-soluble lubricant. In addition, the anti-inflammatory drug can be selected from one or both of dexamethasone and compound betamethasone. The use of a degradable material for the fishbone base layer allows the base layer to gradually degrade after long-term implantation, thereby eliminating the anchoring effect of the base layer rib structure, which is conducive to the complete and intact removal of the electrode probe, and can prevent the probe itself from breaking or remaining in the tissue. At the same time, the material of the fishbone base layer is doped with a lubricant and an anti-inflammatory drug, making the probe implantation process and the removal process after long-term implantation easier, reducing the removal resistance, alleviating physical damage to the tissue, and reducing tissue inflammatory response.

[0046] When the degradable fishbone base layer 1 uses the degradable material PLGA, the degradation rate of the base layer can be changed by controlling the mass percentage ratio of LA and GA according to different usage requirements. For example, when the ratio is 50:50, the complete degradation time is 1-2 months, and when the ratio is 75:25, the complete degradation time is 4-5 months, thereby improving the applicability of the electrode.

[0047] Compared to PLGA, PCL is a semi-crystalline polymer with excellent biocompatibility, biodegradability, and good drug permeability. However, it takes a long time for complete degradation in the body, requiring 2-4 years. Using this material instead of PLGA can significantly extend the implantation duration of neural probe electrodes, making it more suitable for longer-term implants. Furthermore, the advantage of using PCL instead of PLGA lies not only in its longer degradation time, but also in its lower glass transition temperature (approximately -60°C) and higher melting point (approximately 60°C), which makes PCL exhibit good flexibility and processability at physiological temperatures. Furthermore, PCL's high crystallinity and low melting point make it easy to mold at low temperatures while maintaining good mechanical properties. PCL has excellent biocompatibility and persists in the body, allowing cells to grow normally on its scaffold. PCL eventually degrades into carbon dioxide and water, reducing the inflammatory response and foreign body reaction that may be associated with long-term implants. The biodegradability of this material also means that it is gradually absorbed by the body after fulfilling its function, avoiding the risk and cost of secondary surgery to remove the implant that may be required with traditional materials.

[0048] One side surface of the electrode flexible substrate layer 2, along its thickness, is adhered to the degradable fishbone base layer 1, and the other side surface is provided with the electrode conductive metal layer 3. The thickness of the electrode flexible substrate layer 2 is 6 microns. The electrode flexible substrate layer 2 can be made of one or more of polyimide (PI), parylene, and silicone.

[0049] The electrode conductive metal layer 3 includes a metal wire 31 and electrode sites located at the end of the metal wire 31. The electrode sites are a stimulation electrode site 32 and a collection electrode site 33 for performing electrical stimulation and electrophysiological signal collection.

[0050] The electrode flexible packaging layer 4 covers the electrode conductive metal layer 3 and exposes the electrode site area.

[0051] Combine Figure 2 In a specific embodiment of the present invention, the stimulation electrode points 32 are evenly arranged along the length of the electrode flexible substrate layer 2 and located in the middle of the electrode flexible substrate layer 2 in the width direction. The collection electrode points 33 are located on both sides of the stimulation electrode points 32 in the width direction of the electrode flexible substrate layer 2. However, it should be understood that the arrangement of the stimulation electrode points 32 and the collection electrode points 33 is not limited to this, and other arrangements can be adopted as needed.

[0052] Combine Figure 3 In the embodiment shown, the stimulation electrode points 32 are exposed only on the side where the packaging layer is located. On the opposite side of the packaging layer, it is covered with the electrode flexible substrate layer and the degradable fishbone base layer. However, on the other side of the stimulation electrode points 32, the stimulation electrode points 32 may also be exposed, which will be referred to below. Figure 5 Detailed description.

[0053] Next, the preparation method of the degradable fishbone structure flexible neural electrode provided by the present invention is described. The preparation method comprises the following steps:

[0054] Step 1: Prepare a metal sacrificial layer on the carrier of the flexible neural electrode;

[0055] Step 2: preparing a degradable flexible composite material used for the degradable fishbone base layer 1;

[0056] Step 3: forming a degradable fishbone base layer 1 on the metal sacrificial layer using the prepared degradable flexible composite material;

[0057] Step 4: preparing an electrode flexible substrate layer 2 on the formed degradable fishbone base layer 1;

[0058] Step 5: depositing metal on the surface of the electrode flexible substrate layer 2 and etching to obtain the electrode conductive metal layer 3;

[0059] Step 6: preparing an electrode flexible packaging layer 4 on the surface of the electrode conductive metal layer 3, and exposing the collection electrode point 33 area and the stimulation electrode point 32 area on the electrode flexible packaging layer 4;

[0060] Step 7: Remove the sacrificial layer and complete the release of the neural electrode.

[0061] Reference Figure 4 , the preparation method can be achieved by the following steps:

[0062] Step 1: Take a clean silicon wafer as the carrier of the neural probe electrode and sputter a layer of aluminum as a sacrificial layer with a thickness of 0.3 microns;

[0063] Step 2: Prepare a PLGA solution by dissolving PLGA pellets (LA:GA mass percentage of 65:35, number average molecular weight Mn of 6500) in chloroform. The mass proportion of PLGA in the solution is 20 wt%. The PLGA solution is spin-coated on the aluminum sacrificial layer prepared in step 1 at a speed of 3000 rpm for 60 seconds, and then annealed on a 160°C hot plate for 20 minutes to remove the solvent.

[0064] Step 3: As shown in Figure (a), a probe substrate is prepared by wet etching, i.e., a degradable fishbone base layer 1 with a thickness of 1.5 μm;

[0065] Step 4: As shown in Figure (b), a photosensitive PI (HD 4100) is spin-coated on the surface of the degradable fishbone base layer (3800 rpm, 30 s). The PI model used here and in the following steps is HD 4100. The sheet is placed in a muffle furnace for heat curing (nitrogen environment, 300°C, 1 h) to partially imidize the electrode base layer. Then, the electrode flexible substrate layer 2 is prepared by photolithography with a thickness of 6 μm.

[0066] Step 5: As shown in FIG. 5(c), a layer of chromium with a thickness of 20 nanometers is deposited on the surface of the electrode flexible substrate layer by sputtering, followed by a layer of gold with a thickness of 0.2 micrometers. The deposited gold surface is then wet-etched, followed by wet-etching the chromium surface, to form the electrode conductive metal layer 3.

[0067] Step 6: As shown in Figure (d), a layer of PI was spin-coated on the electrode conductive metal layer 3 (3800 rpm, 30 s), and the wafer was placed in a muffle furnace for thermal curing (nitrogen environment, 350°C, 1 h) to partially imidize the electrode base layer;

[0068] Step 7: As shown in FIG. 5( e ), a photolithography process is used to expose the probe collection electrode point area, pads, electrode outline and stimulation electrode point area on the PI to obtain an electrode flexible packaging layer 4 .

[0069] Step 8: Remove the sacrificial layer to complete the release of the neural probe. Specifically, immerse the entire device in a 0.3% dilute hydrochloric acid solution for 24 hours, remove the sacrificial layer, and then soak, rinse and dry it with deionized water to complete the release of the neural probe type electrode.

[0070] After 4-5 months of implantation, the neural probe-type electrode obtained by this process will have its degradable fishbone basal layer completely degraded in the body, eliminating the anchoring effect of the rib structure in the basal layer. With the gradual release of lubricants and anti-inflammatory drugs in the degradable fishbone basal layer, the removal of the probe will be easier, minimizing damage to the tissue during the removal process.

[0071] Now refer to Figure 5 , shows another exemplary embodiment of the degradable fishbone structure flexible neural electrode provided by the present invention. As mentioned above, in this embodiment, both sides of the stimulation electrode point 32 are exposed, thereby obtaining a double-sided electrode probe. The stimulation electrode point of this probe has a more excellent stimulation performance. Figure 4 The preparation process is basically the same, except that in step three, the heat-peelable tape is laser etched to make a convex mold, and then a degradable fishbone base layer is formed on the convex mold; and after step seven is completed, the reverse side of the probe is etched, that is, the fishbone base layer and the electrode flexible substrate layer are etched to expose the other side of the stimulation electrode point of the probe, thereby preparing a double-sided electrode probe.

[0072] Next, refer to Figure 6 The implantation and removal process of the degradable fishbone-structured flexible neural electrode provided by the present invention is described. The figure shows, from left to right: the probe is implanted in the tissue; the degradable fishbone basal layer gradually degrades, releasing the anti-inflammatory drug and lubricant; the degradable fishbone basal layer completely degrades, eliminating the anchoring effect of the rib structure, and the probe is non-destructively removed with the help of the anti-inflammatory drug and lubricant.

[0073] As described above, the degradable fishbone structure flexible neural electrode of the present invention is provided with an electrode flexible substrate layer, an electrode conductive metal layer and an electrode flexible packaging layer on the fishbone base layer including a substrate and a rib structure. On the one hand, the fishbone structure is utilized to ensure that the electrode is firmly anchored after long-term implantation in the body, thereby reducing the influence of brain tissue micro-movements on the electrode acquisition and stimulation functions; on the other hand, by using degradable materials for the fishbone base layer, the base layer can be gradually degraded after long-term implantation, eliminating the anchoring effect of the rib structure of the base layer, which is conducive to the complete and intact removal of the electrode probe, and can avoid the probe itself from breaking or remaining in the tissue. At the same time, the material of the fishbone base layer is doped with lubricants and anti-inflammatory drugs, which makes the probe implantation process and the removal process after long-term implantation easier, which can reduce the removal resistance, alleviate physical damage to the tissue, and reduce tissue inflammatory response.

[0074] Finally, it should be noted that the features mentioned and / or illustrated in the above description of the exemplary embodiments of the present invention may be incorporated into one or more other embodiments in the same or similar manner, combined with features in other embodiments, or substituted for corresponding features in other implementations. The technical solutions obtained by such combination or substitution shall also be deemed to be included in the scope of protection of the present invention.

Claims

1. A degradable fishbone structure flexible neural electrode, characterized by: It includes a degradable fishbone base layer, an electrode flexible substrate layer, an electrode conductive metal layer and an electrode flexible packaging layer; The degradable fishbone base layer is made of a degradable flexible composite material doped with a lubricant and an anti-inflammatory drug, and includes a base plate and a plurality of rib structures extending parallel to both sides of the base plate in the same plane as the base plate along the length direction of the base plate; One side surface of the electrode flexible substrate layer in the thickness direction is adhered to the degradable fishbone base layer, and the other side surface is provided with the electrode conductive metal layer; The electrode conductive metal layer includes a metal wire and electrode sites located at the ends of the metal wire, wherein the electrode sites are stimulation electrode sites and collection electrode sites; The electrode flexible packaging layer covers the electrode conductive metal layer and exposes the electrode site area.

2. The degradable fishbone structure flexible neural electrode according to claim 1, characterized in that: The degradable fishbone base layer is made of polylactic acid-glycolic acid copolymer or polycaprolactone mixed with lubricant and anti-inflammatory drugs.

3. The degradable fishbone structure flexible neural electrode according to claim 1 or 2, characterized in that: The lubricant in the material of the degradable fishbone base layer is selected from one or more of glycerin lubricant, silicone oil lubricant and water-soluble lubricant.

4. The degradable fishbone structure flexible neural electrode according to claim 1 or 2, characterized in that: The anti-inflammatory drug in the material capable of degrading the fishbone basal layer is selected from one or both of dexamethasone and compound betamethasone.

5. The degradable fishbone structure flexible neural electrode according to claim 1 or 2, characterized in that: The electrode flexible substrate layer is made of one or more of polyimide, parylene and silica gel.

6. The degradable fishbone structure flexible neural electrode according to claim 1 or 2, characterized in that: The thickness of the degradable fishbone base layer is 1.5 microns, and the thickness of the electrode flexible substrate layer is 6 microns.

7. The degradable fishbone structure flexible neural electrode according to claim 1 or 2, characterized in that: The stimulation electrode points are evenly arranged along the length direction of the electrode flexible substrate layer and located in the middle in the width direction of the electrode flexible substrate layer. The collection electrode points are located on both sides of the stimulation electrode points in the width direction of the electrode flexible substrate layer.

8. A method for preparing a degradable fishbone structure flexible neural electrode according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: Prepare a metal sacrificial layer on the carrier of the flexible neural electrode; Step 2: preparing a degradable flexible composite material for the degradable fishbone base layer; Step 3: forming a degradable fishbone base layer on the metal sacrificial layer using the prepared degradable flexible composite material; Step 4: preparing an electrode flexible substrate layer on the formed degradable fishbone base layer; Step 5: depositing metal on the surface of the electrode flexible substrate layer and etching to obtain an electrode conductive metal layer; Step 6: preparing an electrode flexible packaging layer on the surface of the electrode conductive metal layer, and exposing the collection electrode point area and the stimulation electrode point area on the electrode flexible packaging layer; Step 7: Remove the sacrificial layer and complete the release of the neural electrode.

9. The preparation method according to claim 8, characterized in that Step 2 includes the following steps: dissolving polylactic acid-co-glycolic acid microspheres in chloroform to prepare a material capable of degrading the fishbone basal layer.

10. The preparation method according to claim 9, characterized in that In step 3, the thermal peeling tape is laser etched to produce a convex mold, and a degradable fishbone base layer is formed on the convex mold; and after step 7, the fishbone base layer and the electrode flexible substrate layer of the electrode are etched to expose the side of the stimulation electrode point opposite to the electrode flexible packaging layer, thereby preparing a double-sided electrode probe.

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