A biological fusion type three-dimensional neural electrode

Abstract

The application discloses a kind of biological fusion type three-dimensional nerve electrode, including depth sensing unit and two parts of plane sensing unit.Local field potential and deep brain electrical complex signal can be acquired simultaneously in cortical surface, and it has good biocompatibility and compliance.The maximum length of plane sensing unit is 5-20mm, and the thickness is less than 100μm.To ensure the accuracy of the nerve electrode, the minimum diameter of the sensing circuit is less than or equal to 50μm, the diameter of the depth sensing unit is less than or equal to 75μm, and the implantation depth range is 2-5mm.The number of sensing channels in the plane sensing unit part is 16-50, and the number of sensing channels in the depth sensing unit part is 25-60.During the manufacturing process, microchannels and other coupling structures are reserved on the plane sensing unit, and the integrated manufacturing of the nerve electrode is realized by printing and assembling from bottom to top layer by layer.

Description

Technical Field

[0001] This invention belongs to the field of neural electrode technology, specifically relating to a biofusion-type three-dimensional neural electrode. Background Technology

[0002] Neuroscience is one of the most important areas of scientific research worldwide and a key battleground in global scientific competition. Implantable neural electrodes can acquire neural electrical signals and input commands to specific areas of the cerebral cortex, which is of great significance and application value for achieving the long-standing advanced goals of neuroscience, such as understanding, controlling, and developing the brain. Currently, implantable neural interfaces have shown great promise in the medical field, including deep brain stimulation for the treatment of neurological diseases, brain-controlled tools, and brain enhancement. Stable multidimensional neural interface technology can not only provide more precise means of decoding and regulating neural activity for a deeper understanding of the uniqueness of brain commands and for research on the diagnosis, treatment, and repair of brain diseases, but also help to achieve deep integration of modern equipment such as exoskeletons with the brain's nervous system, effectively restoring the limb control, sensory, and memory abilities of people with neurological injuries, thus possessing significant research and application value.

[0003] Implantable neural electrodes, in direct contact with nerve tissue, serve as a bridge for electrical signal exchange between the nerve tissue and external instruments. The electrodes function in two ways: first, by detecting and recording action potentials (spikes) generated by neural activity; and second, by applying input signals to target neural regions to electrically stimulate or inhibit neural activity. Currently, implantable neural electrodes can be mainly categorized into microfilament array electrodes, Utah electrodes, and Michigan electrodes. However, the development and application of neural electrodes face certain challenges, primarily manifested in the inherent contradiction between electrode miniaturization and conductivity; the contradiction between electrode flexibility and implantability; and the contradiction between electrode biocompatibility and electrical performance. Most existing electrodes only target signal acquisition and stimulation of a single region on the cortical surface or deep within the brain, failing to simultaneously acquire EEG signals across the entire three-dimensional range, including both surface field potentials and local action potentials. Therefore, constructing a biocompatible neural interface that can simultaneously acquire local field potentials in the cortical surface and complex signals from deep EEG, and promote the biofusion of cells and neural interfaces by inducing neuronal synaptic attachment and network formation, is an inevitable requirement in this field. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a biofusion-type three-dimensional neural electrode to address the shortcomings of the prior art, thereby solving the technical problem of synchronous recording of three-dimensional spatial EEG signals and realizing the function of simultaneously acquiring local field potentials of the cortical surface and complex signals of deep EEG.

[0005] The present invention adopts the following technical solution:

[0006] A biofusion-type three-dimensional neural electrode includes a planar sensing unit and multiple depth sensing units arranged on the planar sensing unit. The depth sensing units and the planar sensing units are coupled together to form a biofusion-type three-dimensional neural electrode, which can simultaneously acquire local field potentials of the cortical surface and complex signals of deep brain waves.

[0007] Specifically, the planar sensing unit has a rectangular, circular, or polygonal structure, and the minimum diameter of the sensing circuit is less than or equal to 50 μm.

[0008] Furthermore, the maximum length of the planar sensing unit is 5–20 mm, and the thickness is less than 100 μm.

[0009] Furthermore, the planar sensing unit comprises a three-layer structure, consisting of a rigid planar substrate, a soft planar biological substrate layer, and a biological encapsulation layer from bottom to top.

[0010] Furthermore, the soft planar biological substrate layer is provided with coupling grooves and conductive lines, and the biological encapsulation layer is provided with pre-electrode openings.

[0011] Specifically, the diameter of the depth sensing unit is less than or equal to 75 μm, and the implantation depth is 2–5 mm.

[0012] Furthermore, the depth sensing unit comprises a three-layer structure, consisting of a main electrode material, a conductive biological layer, and a variable modulus layer, from the inside out.

[0013] Specifically, the elastic modulus of the depth sensing unit is less than 100 kPa, and the elongation of the thin-film sensing unit of the planar sensing unit is greater than 20%.

[0014] Specifically, the depth sensing unit has 25 to 60 sensing channels, and the planar sensing unit has 16 to 50 sensing channels.

[0015] Specifically, the biofusion-type stereotactic neural electrode has an in vivo EEG signal detection rate of over 80%, a conductivity of 3 to 5 times that of the platinum metal electrode, and is continuously monitored for 60 days.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects:

[0017] A bio-integrated three-dimensional neural electrode, by coupling a depth electrode and a planar electrode, can simultaneously acquire local field potentials in the cortical surface and complex signals from deep EEG, solving the challenge of synchronous recording of EEG signals in three-dimensional space. This promises to provide a more reliable front-end information acquisition pathway for neural decoding and precise control. Furthermore, a novel approach is proposed: directly printing carbon-based sensing circuits onto a highly biocompatible and compliant hydrogel substrate to fabricate patch electrodes. This approach is expected to address the long-standing problem of silicon-based sensors gradually failing due to differences in bio / physical compatibility with brain tissue, enabling the free fabrication of purely flexible, bio-based sensing interface devices. In the depth sensing unit, a core-sheath structure for implantable probe electrodes is proposed. By encapsulating a micron-sized carbon-based core with an adjustable modulus and microstructure of biocamouflage layer, it aims to induce cortical neurons and synapses and reduce scarring effects caused by foreign body reactions in glial cells. The elastic modulus of the camouflage layer varies by more than two orders of magnitude, resolving the long-standing contradiction between the high stiffness required for implantation and high compliance during use.

[0018] Furthermore, the minimum diameter of the planar sensing unit circuit is less than or equal to 50 μm, enabling the realization of more recording sites within a smaller electrode plane. In addition, the thickness of the planar sensing unit is less than 100 μm, improving the adhesion between the electrode and the cerebral cortex after implantation.

[0019] Furthermore, the planar sensing unit comprises, from top to bottom, a rigid planar substrate, a soft planar biological substrate, and a biological encapsulation layer, which can satisfy both the good adhesion between the electrode and the cerebral cortex and good biocompatibility, and also facilitate subsequent encapsulation.

[0020] Furthermore, the planar sensing unit has coupling grooves and conductive lines on its soft planar biological substrate layer, and pre-electrode openings on its biological encapsulation layer. This facilitates coupling and assembly with the depth sensing unit.

[0021] Furthermore, the depth sensing unit has a diameter of less than or equal to 75 μm, which reduces the volume of the electrode, reduces the scarring effect after electrode implantation, and improves the lifespan of the electrode.

[0022] Furthermore, the main material of the depth sensing unit is a conductive material such as a metal or carbon-based material; the conductive biolayer is a biocompatible hydrogel layer doped with conductive materials; the variable modulus layer is a material with high modulus after solidification that can be rapidly degraded in brain tissue, such as polyethylene glycol or silk fibroin, which facilitates electrode implantation. The biolayer material, after degradation, directly contacts the brain tissue to ensure good biocompatibility of the electrode.

[0023] Furthermore, the elastic modulus of the depth sensing unit is less than 100 kPa, reducing the modulus difference between the electrode and brain tissue, and the elongation of the planar sensing unit is greater than 20%, which facilitates better adhesion of the electrode to the brain tissue after implantation.

[0024] In summary, the biofusion-type three-dimensional neural electrode of this invention can simultaneously acquire local field potentials on the surface of the cortex and complex signals from deep EEG. It also proposes a novel approach to fabricate patch electrodes by directly printing sensing circuits on a highly biocompatible and compliant hydrogel substrate. Furthermore, it proposes to establish a micron-level core wire-wrapped biocamouflage layer with adjustable modulus and microstructure to induce nerve cells and synapses in the cortex and reduce the scarring effect caused by foreign body reactions in glial cells.

[0025] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the depth sensing unit structure;

[0028] Figure 3 This is a schematic diagram of a planar sensing unit structure.

[0029] Among them: 1. Depth sensing unit; 101. Electrode body; 102. Conductive biological layer; 103. Variable modulus layer; 2. Planar sensing unit; 201. Planar substrate; 202. Conductive circuit; 203. Soft planar biological substrate layer; 204. Biological encapsulation layer; 205. Coupling groove; 206. Electrode opening. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "one side," "one end," and "one side," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0034] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0035] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0036] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0037] This invention provides a bio-integrated three-dimensional neural electrode, comprising a depth sensing unit and a planar sensing unit. It can simultaneously acquire local field potentials in the cortical surface and complex deep EEG signals, exhibiting good biocompatibility and compliance. The planar sensing unit has a maximum length of 5–20 mm and a thickness of less than 100 μm. To ensure the precision of the neural electrode, the minimum diameter of the sensing circuit is less than or equal to 50 μm. The depth sensing unit has a diameter less than or equal to 75 μm, with an implantation depth ranging from 2 to 5 mm. The planar sensing unit has 16–50 sensing channels, and the depth sensing unit has 25–60 sensing channels. During manufacturing, microchannels and other coupling structures are pre-defined on the planar sensing unit, and the neural electrode is integrated through bottom-up, layer-by-layer printing and assembly.

[0038] Please see Figure 1 The present invention discloses a biofusion-type three-dimensional neural electrode, comprising two parts: a depth sensing unit 1 and a planar sensing unit 2. Multiple depth sensing units 1 are spaced apart on the planar sensing unit 2. The depth sensing units 1 and the planar sensing units 2 are coupled to form a biofusion-type three-dimensional neural electrode, which can simultaneously acquire local field potentials of the cortical surface and complex signals of deep brain waves, and has good biocompatibility and compliance.

[0039] The planar sensing unit 2 is rectangular, circular, or polygonal, with a maximum length of 5–20 mm, a thickness of less than 100 μm, and a minimum diameter of 50 μm for the sensing circuit. The depth sensing unit 1 has a diameter of 75 μm or less and an implantation depth of 2–5 mm.

[0040] The planar sensing unit 2 has 16 to 50 sensing channels, and the depth sensing unit 1 has 25 to 60 sensing channels.

[0041] The thin-film sensing unit of the planar sensing unit 2 has an elongation greater than 20%; the elastic modulus of the depth sensing unit 1 is less than 100 kPa.

[0042] Please see Figure 2The depth sensing unit 1 includes a main electrode material 101, a conductive biological layer 102, and a variable modulus layer 103. The main electrode material 101 includes multiple main electrode materials 101, which are disposed within the variable modulus layer 103. The conductive biological layer 102 is disposed on the outside of each main electrode material 101.

[0043] The main electrode material 101 is a conductive material such as a metal or a carbon-based material;

[0044] The conductive biolayer 102 is a biocompatible hydrogel layer doped with a conductive material.

[0045] The variable modulus layer 103 is a material with a high modulus after solidification that can be rapidly degraded in the brain tissue region, such as polyethylene glycol and silk fibroin. Its function is to facilitate electrode implantation. The bio-layer material that comes into direct contact with the brain tissue after degradation is to ensure good biocompatibility of the electrode.

[0046] Each electrode bundle contains multiple electrode wires arranged at different depths. A conductive biological membrane coats the electrode wires at different depths, creating an effect that allows for the measurement of electrical signals at different dermal depths.

[0047] Please see Figure 3 The planar sensing unit 2 includes a rigid planar substrate 201, a soft planar biological substrate layer 203, a biological encapsulation layer 204, and conductive lines 202. The biological encapsulation layer 204 is disposed on the upper side of the soft planar biological substrate layer 203, and the rigid planar substrate 201 is disposed on the lower side of the soft planar biological substrate layer 203.

[0048] The material of the rigid planar substrate 201 is biodegradable.

[0049] The elastic modulus of the soft planar biological base layer 203 and the biological encapsulation layer 204 are matched with those of the cerebral cortex and have good biocompatibility, such as hydrogels and other types of materials.

[0050] The conductive circuit 202 is made of a material with good conductivity, such as metal or carbon-based material.

[0051] The soft planar biological substrate layer 203 is provided with a coupling groove 205 to facilitate the connection of the depth sensing unit 1 circuit; the biological encapsulation layer 204 has reserved electrode openings 206 that can expose the positions of the planar sensing unit 2 and the depth sensing unit 1.

[0052] The biofusion-type stereoscopic neural electrode of this invention has an in vivo EEG signal detection rate of over 80% and is continuously monitored for 60 days to meet the requirement of high biofusion.

[0053] In summary, this invention provides a biofusion-type three-dimensional neural electrode that enables the simultaneous acquisition of local field potentials in the cortical surface and complex signals from deep EEG, solving the problem of synchronous recording of EEG signals in three-dimensional space.

[0054] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A biofusion-type three-dimensional neural electrode, characterized in that, The device includes a planar sensing unit (2) and multiple depth sensing units (1) arranged on the planar sensing unit (2). The depth sensing unit (1) and the planar sensing unit (2) are coupled together to form a biofusion-type three-dimensional neural electrode, which can simultaneously acquire local field potentials of the cortical surface and complex signals of deep brain waves. The depth sensing unit (1) includes a three-layer structure, from the inside to the outside: the main electrode material (101), the conductive biological layer (102), and the variable modulus layer (103). The planar sensing unit (2) includes a three-layer structure, from the bottom to the top: a rigid planar substrate (201), a soft planar biological substrate layer (203), and a biological encapsulation layer (204). The soft planar biological substrate layer (203) is provided with a coupling groove (205) and a conductive line (202). The biological encapsulation layer (204) is pre-set with an electrode opening (206).

2. The biofusion-type three-dimensional neural electrode according to claim 1, characterized in that, The planar sensing unit (2) is a rectangular, circular or polygonal structure, and the minimum diameter of the sensing line is less than or equal to 50 μm.

3. The biofusion-type three-dimensional neural electrode according to claim 2, characterized in that, The maximum length of the planar sensing unit (2) is 5 to 20 mm and the thickness is less than 100 μm.

4. The biofusion-type three-dimensional neural electrode according to claim 1, characterized in that, The diameter of the depth sensing unit (1) is less than or equal to 75 μm, and the implantation depth is 2 to 5 mm.

5. The biofusion-type three-dimensional neural electrode according to claim 1, characterized in that, The elastic modulus of the depth sensing unit (1) is less than 100 kPa, and the elongation of the thin film sensing unit of the planar sensing unit (2) is greater than 20%.

6. The biofusion-type three-dimensional neural electrode according to claim 1, characterized in that, The depth sensing unit (1) has 25 to 60 sensing channels, and the planar sensing unit (2) has 16 to 50 sensing channels.

7. The biofusion-type stereoscopic neural electrode according to any one of claims 1 to 6, characterized in that, The detection rate of in vivo EEG signals using the biofusion-type stereoscopic neural electrode is greater than 80%, and it is continuously monitored for 60 days.

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