A front-end structure of brain electrode and its application

Abstract

The present invention relates to the technical field of brain electrodes, and the present invention provides a front-end structure of a brain electrode and its application. The front-end structure of the brain electrode includes a brain electrode structure and a flexible connector, the brain electrode structure is used to collect signals from brain tissue, the brain tissue is far away from the parietal lobe, one end of the flexible connector is connected to the brain electrode structure, and the other end of the flexible connector is connected to a signal processing device; the length of the flexible connector is greater than or equal to a preset length, so that the flexible connector can approach the brain tissue through the nasal cavity, so that the brain electrode structure connected thereto can reach the deep brain area, and realize signal collection with less trauma to the area.

Description

Technical Field

[0001] The present invention relates to the technical field of brain electrodes, and in particular to a front end structure of a brain electrode and its application. Background Art

[0002] EEG monitoring has always played an irreplaceable role in the diagnosis and surgical positioning of brain diseases. In recent years, with the launch of the "Brain Project" worldwide, effective and high-quality EEG signal acquisition has become increasingly important, which will directly contribute to the decoding of brain functions and promote the development of a series of high-tech technologies based on this, such as brain-computer interfaces and neural regulation.

[0003] The method for collecting EEG signals mainly relies on brain electrodes. Currently, there are four types of brain electrodes that are widely used: 1) scalp EEG; 2) cortical EEG; 3) cortical microelectrode; 4) deep EEG. Each of these four electrodes has its own advantages, but also has its own application limitations. In general, the planar cortical electrode (ECoG) between the intracranial microelectrode and the scalp external EEG places the electrode on the surface of the cortex under the dura mater. Due to its small invasive damage, the ECoG collected from the surface of the cortex has a higher signal-to-noise ratio than EEG, a higher resolution (sub-micron level), and a larger signal acquisition frequency range. It contains information on the activity of cortical neuron groups and has broad application prospects in the diagnosis and monitoring of brain diseases and the performance improvement of brain-computer interface systems. ECoG acquisition can be considered to have achieved an ideal balance between signal fidelity and clinical practicality, so ECoG electrodes have been widely used in clinical practice.

[0004] But for now, these three types of brain electrodes can still only detect electrophysiological signals on the superficial surface of the cerebral cortex, and it is difficult to collect electrical signals from nuclei deep in the brain. Many important neuronal nuclei are located deep in the brain, such as the hypothalamic nuclei, which are known as the "heart of the brain". It is the center for regulating basic physiological activities of the human body and participates in regulating the autonomic nervous system, such as controlling water and salt metabolism, regulating body temperature, eating, sleep, reproduction, visceral activities, and emotions, etc. It affects the activities of the nervous system and multiple other physiological systems. It can be considered a bridge for communication between multiple physiological systems and an indispensable key link in the study of closed-loop brain neural pathways. However, the academic community has not yet reported on the detection of electrical signals in this area. Summary of the invention

[0005] The present invention aims to solve the technical problem that the brain electrode structure in the prior art is difficult to realize signal acquisition in deep brain areas.

[0006] In order to solve the above technical problems, the present application discloses a front-end structure of an electroencephalogram electrode, which comprises:

[0007] A brain electrode structure, the brain electrode structure is used to collect signals from brain tissue; the brain tissue is far away from the parietal lobe;

[0008] A flexible connector, one end of which is connected to the brain electrode structure, and the other end of which is connected to the signal processing device; the length of the flexible connector is greater than or equal to a preset length so that the flexible connector can approach the brain tissue through the nasal cavity.

[0009] Optionally, the brain electrode structure includes a first structure and a second structure, the second structure being provided with a recording electrode; the second structure includes N substructures; N is an integer greater than or equal to 2; there is a preset distance between adjacent substructures among the N substructures, so that the N substructures can gather toward the center of the first structure to form an arc surface; the N substructures are arranged around the edge of the first structure.

[0010] Optionally, a pad array is provided on the top of the first structure or on any one of the N substructures;

[0011] The pad array is connected to the pad structure of the external connection structure accordingly.

[0012] Optionally, the recording electrode and the pad array are located on the same plane;

[0013] Each of the remaining substructures of the N substructures includes a first substrate layer, an electrode wire layer, and a first insulating layer stacked in sequence;

[0014] The electrode wire layer includes wires and the recording electrode;

[0015] One end of the wire is connected to the recording electrode, and the other end of the wire is connected to a corresponding pad in the pad array;

[0016] The insulating layer is provided with an electrode hole for exposing the recording electrode.

[0017] Optionally, the pad array is provided at the bottom of the first structure;

[0018] The recording electrode comprises a first recording electrode and a second recording electrode;

[0019] The first recording electrode is arranged on the top of the first structure;

[0020] Each of the N substructures includes a first substrate layer, a wire layer, a second substrate layer, a second recording electrode layer and a first insulating layer stacked in sequence;

[0021] The second substrate layer is provided with a first electrode hole, and the wire layer is connected to the second recording electrode of the second recording electrode layer through the first electrode hole;

[0022] A second electrode hole is provided on the first insulating layer, and the second electrode hole is used to expose the second recording electrode;

[0023] The first structure includes a third substrate layer, a fourth substrate layer, and a second insulating layer;

[0024] The third base layer is provided with a through hole array;

[0025] Each through hole in the through hole array is provided with a corresponding pad of the pad array;

[0026] The second insulating layer is provided with a third electrode hole, and the third electrode hole is used to expose the first recording electrode;

[0027] The third base layer is connected to the first base layer to form an integrated structure;

[0028] The fourth base layer is connected to the second base layer to form an integrated structure;

[0029] The first insulating layer and the second insulating layer are connected to form an integral structure.

[0030] Optionally, each of the N substructures includes a first substrate layer, a wire layer, a second substrate layer, a recording electrode layer and a first insulating layer stacked in sequence;

[0031] The second substrate layer is provided with a first electrode hole, and the wire layer is connected to the recording electrode of the recording electrode layer through the first electrode hole;

[0032] The insulating layer is provided with a second electrode hole, and the second electrode hole is used to expose the recording electrode;

[0033] The first base layer of any one of the N substructures is provided with a through hole array;

[0034] Each through hole in the through hole array is provided with a corresponding solder pad of the solder pad array.

[0035] Optionally, the shape of the second structure includes triangle, quadrilateral, pentagon or hexagon.

[0036] Optionally, the second structure includes M first substructures and NM second substructures; M is an integer greater than or equal to 1;

[0037] The M first substructures are arranged along the edge of the first structure and connected to the edge of the first structure;

[0038] The NM second substructures are arranged along the outer edges formed by the M first substructures, and each of the NM second substructures is connected to the corresponding first substructure.

[0039] On the other hand, the present application also discloses an application of the above-mentioned front-end structure of the brain electrode to collect brain signals from deep brain nuclei.

[0040] By adopting the above technical solution, the front-end structure of the brain electrode provided by the present application has the following beneficial effects:

[0041] The front-end structure of the brain electrode provided by the present application includes a brain electrode structure and a flexible connector. The brain electrode structure is used to collect signals from brain tissue, and the brain tissue is far away from the parietal lobe. One end of the flexible connector is connected to the brain electrode structure, and the other end of the flexible connector is connected to a signal processing device. The length of the flexible connector is greater than or equal to a preset length, so that the flexible connector can approach the brain tissue through the nasal cavity, thereby enabling the brain electrode structure connected thereto to reach the deep brain area and achieve signal collection with less trauma to the area. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 This is a schematic diagram of an optional brain electrode front end structure of the present application;

[0044] Figure 2 This is a schematic diagram of the location of the hypothalamic nuclei in the head;

[0045] Figure 3 A schematic diagram of the structure of the first optional brain electrode structure provided in this application;

[0046] Figure 4 A schematic diagram of the structure of a second optional brain electrode structure provided in this application;

[0047] Figure 5 A schematic diagram of the structure of a third optional brain electrode structure provided for this application;

[0048] Figure 6 A schematic diagram of the structure of a fourth optional brain electrode structure provided in this application;

[0049] Figure 7 A schematic diagram of the structure of a fifth optional brain electrode structure provided in this application;

[0050] Figure 8 The structure and stress distribution diagram of arc surfaces of different radii formed by the foldable brain electrode structure provided in this application;

[0051] Fig. 9 A flow chart for preparing an optional brain electrode structure for this application;

[0052] Fig.10 It is a structural schematic diagram of the arc mold.

[0053] The following is a supplementary description of the attached drawings:

[0054] 1-brain electrode structure; 101-first structure; 102-electrode array; 2-flexible connector; 3-second structure; 31-substructure; 311-first substructure; 312-second substructure; 4-recording electrode; 41-first recording electrode; 42-second recording electrode; 5-first base layer; 6-wire layer; 7-second base layer; 71-first electrode hole; 8-second recording electrode layer; 9-first insulating layer; 91-second electrode hole; 10-third electrode hole; 11-silicon substrate; 12-sacrificial layer; 13-support layer; 14-pad array; 15-packaging layer; 16-insulating layer. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0056] The term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present application. In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may include one or more of the features explicitly or implicitly. Moreover, the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here.

[0057] For the purpose of the following detailed description, it should be understood that the present invention may adopt various alternative changes and step sequences, unless expressly specified to the contrary. In addition, except in any operating examples, or otherwise indicated, all numbers representing the amount of ingredients used in the specification and claims should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise indicated, the numerical parameters set forth in the following specification and the attached claims are approximate values ​​that vary according to the desired performance to be obtained by the present invention. At least it is not intended to limit the application of the doctrine of equivalents to the scope of the claims, and each numerical parameter should at least be interpreted according to the number of reported significant figures and by applying ordinary rounding techniques.

[0058] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0059] When a numerical range is disclosed herein, the above range is deemed to be continuous and includes the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all sub-ranges included therein. For example, a specified range from "1 to 10" should be deemed to include any and all sub-ranges between a minimum of 1 and a maximum of 10. Exemplary sub-ranges of ranges 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.

[0060] Using brain electrodes to collect signals from different brain tissue areas and studying the collected signals has become a hot topic, but the existing technology is still stagnant in studying the brain tissue near the top of the head. This is because if the existing deep brain stimulation / collection method (using craniotomy attachment) is used, it will inevitably cause damage to the brain tissue. Therefore, refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of an optional front-end structure of an EEG electrode in the present application. The front-end structure of the EEG electrode provided in the present application includes an EEG electrode structure 1 and a flexible connector 2. The EEG electrode structure 1 is used to collect signals from brain tissue, which is far away from the parietal lobe. One end of the flexible connector 2 is connected to the EEG electrode structure 1, and the other end of the flexible connector 2 is connected to a signal processing device. The length of the flexible connector 2 is greater than or equal to a preset length, so that the flexible connector 2 can approach the brain tissue through the nasal cavity, so that the EEG electrode structure 1 connected thereto can reach the deep brain area, and realize signal collection with less trauma to the area.

[0061] Optionally, the preset length includes but is not limited to 0.5, 0.6, 0.8 or 1 meter, and the preset length is at least greater than 0.5 meter.

[0062] In an optional embodiment, the front-end structure of the brain electrode can be applied to deep brain nuclei. The deep brain nuclei can be the hypothalamic nuclei, which are the center for regulating basic physiological activities of the human body and participate in regulating the autonomic nervous system, such as controlling water and salt metabolism, regulating body temperature, eating, sleep, reproduction, visceral activities and emotions, etc., affecting the activities of the nervous system and other multiple physiological systems. It can be considered as a bridge for communication between multiple physiological systems and an indispensable key link in the study of closed-loop brain neural pathways. However, the academic community has not yet reported on the detection of electrical signals in this area. See Figure 2 , Figure 2 This is a schematic diagram of the location of the hypothalamic nucleus on the head. The flexible electrode is implanted through the nasal cavity and placed at the hypothalamic nucleus at the base of the skull.

[0063] Optionally, the flexible connector 2 may be a flexible printed circuit board.

[0064] Optionally, the flexible printed circuit board and the brain electrode structure are connected by heat pressing using anisotropic conductive films.

[0065] Optionally, the above-mentioned brain electrode structure 1 can be a commonly used strip or flat plate structure, see Figure 3 , Figure 3 The schematic diagram of the structure of the first optional brain electrode structure provided in the present application. The entire brain electrode structure 1 is a flat plate structure, on which an electrode array 102 can be arranged in an array. However, for a curved surface with a relatively large curvature value, when the brain electrode of the planar structure is attached thereto, wrinkles are easily formed, resulting in application concentration there, reducing the reliability of the brain electrode; and the connection plate at the rear end of the brain electrode in the prior art is huge in area, which is difficult to meet the surgical plan for clinical implantation and is difficult to operate clinically. Therefore, in another optional embodiment, refer to Figure 4 , Figure 4A schematic diagram of the structure of the second optional brain electrode structure provided in the present application. The brain electrode structure 1 includes a first structure 101 and a second structure 3, and a recording electrode 4 is provided on the second structure 3; the second structure 3 includes N substructures 31; N is an integer greater than or equal to 2; there is a preset distance between adjacent substructures 31 in the N substructures 31, so that the N substructures 31 can gather toward the center of the first structure 101 to form an arc surface; the N substructures 31 are arranged around the edge of the first structure 101, because the brain electrode structure 1 can be set to fold into arc surfaces of different arcs as needed, it is convenient to adapt to brain tissues with different arc surfaces, and because the brain electrode structure 1 can be folded and gathered, it can be folded into a spherical shape before placing the electrode structure on the brain tissue, reducing the occupied space of the brain electrode structure 1, and when it is delivered to the designated brain tissue, it can be unfolded to form a structure of the required arc, with the characteristics of multiple detection channels and small wound surface, realizing flexible electrode minimally invasive deep brain detection, breaking through the bottleneck.

[0066] It should be noted that the above-mentioned brain electrode structure 1 can be Figure 3 The structure shown can also be Figure 4 The structure shown, when the brain electrode structure 1 is Figure 3 In the structure shown, in order to ensure that the brain electrode structure 1 can be delivered to the designated hypothalamic nucleus through the nasal cavity, the size of the brain electrode structure 1 needs to be adjusted.

[0067] Optionally, the above-mentioned brain electrode structure 1 can be used to collect brain signals from the hypothalamic nucleus after tumor removal. The cavity left after tumor removal (see Figure 2 ), so that the physiological electrical signals of the hypothalamic nuclei can be directly collected.

[0068] from Figure 2 It can be seen that although the shape and size of the cavity formed by the tumor are different, they are all dome-shaped as a whole, so the foldable brain electrode structure designed above can adapt to the cavity arch surface with different curvature radii, ensuring that the brain electrode structure 1 can be closely attached to the cavity surface. And the sphere-like unfolded plane outer contour provided by the present application can also be folded and spliced ​​to restore it to a small spherical surface (see below). Fig.10 ), thereby facilitating the shape fixation of the device and facilitating surgical implantation operations.

[0069] In a feasible embodiment, the shape of the second structure 3 includes a triangle, a quadrilateral, a pentagon or a hexagon. The shape of the first structure 101 is not limited, and can be the same as the second structure 3, or a circle or other special shapes.

[0070] In a possible embodiment, see Figure 5 , Figure 5This is a schematic diagram of the structure of the third optional brain electrode structure provided by the present application. The substructures 31 in the second structure 3 are arranged around the edge of the first structure 101. Of course, depending on the size of the arc surface to be covered, in order to make the brain electrode structure 1 cover as many arc surfaces as possible; see Figure 6 , Figure 6 This is a schematic diagram of the structure of the fourth optional brain electrode structure provided by the present application. The second structure 3 includes M first substructures 311 and NM second substructures 312, where M is an integer greater than or equal to 1, the M first substructures 311 are arranged along the edge of the first structure 101 and connected to the edge of the first structure 101, the NM second substructures 312 are arranged along the outer edge formed by the M first substructures 311, and each of the NM second substructures 312 is connected to the corresponding first substructure 311. Of course, in order to further increase the coverage area of ​​the electrode structure while reducing stress concentration at the bending point, the second structure 3 can be further divided into multi-layer substructures 31, that is, the second structure 3 can include M first substructures 311, L second substructures 312 and NML third substructures 31, wherein N is an integer greater than or equal to 3, L is an integer greater than or equal to 1, the first substructure 311 is a substructure 31 directly connected to the edge of the first structure 101, the second substructure 312 is a substructure 31 connected to the outer edge of the first substructure 311, and the third substructure 31 is a substructure 31 connected to the outer edge of the second substructure 312.

[0071] It should be noted that the outer edges of the first substructure 311 , the second substructure 312 and the third substructure 31 are edges away from the center of the first structure 101 .

[0072] Generally, the brain electrode structure 1 includes a connected recording electrode 4 and a pad array 14, wherein the recording electrode 4 is used to collect electroencephalographic signals, and the pad array 14 is used to connect to an external signal acquisition device. In a feasible embodiment, the recording electrode 4 and the pad array 14 are located on the same plane; each substructure 31 of the remaining substructures 31 of the N substructures 31 includes a first base layer 5, an electrode wire layer 6 and a first insulating layer 16 stacked in sequence, and the electrode wire layer 6 includes a wire and the recording electrode 4, one end of the wire is connected to the recording electrode 4, and the other end of the wire is connected to the corresponding pad in the pad array 14, and the first insulating layer 16 is provided with an electrode hole for exposing the recording electrode 4. Optionally, the pad array 14 can be arranged on the top of the first structure 101, or on the top of any one of the N substructures 31.

[0073] In another feasible embodiment, the recording electrode 4 and the pad array 14 can be located on opposite sides of the entire brain electrode structure 1, so that the side with the recording electrode 4 can be better attached to the brain tissue. Figure 7 , Figure 7 A schematic diagram of the structure of the fifth optional brain electrode structure provided by the present application. The pad array 14 can be arranged at the bottom of the first structure 101, the recording electrode 4 includes a first recording electrode 41 and a second recording electrode 42, the first recording electrode 41 is arranged on the top of the first structure 101, each substructure 31 of the N substructures 31 includes a first base layer 5, a wire layer 6, a second base layer 7, a second recording electrode layer 8 and a first insulating layer 16 stacked in sequence, the second base layer 7 is provided with a first electrode hole 71, the wire layer 6 is connected to the second recording electrode 42 of the second recording electrode layer 8 through the first electrode hole 71, the first insulating layer 16 is provided with a second electrode hole 91, The second electrode hole 91 is used to expose the second recording electrode 42. The first structure 101 includes a third base layer, a fourth base layer and a second insulating layer. The third base layer is provided with a through hole array. Each through hole in the through hole array is provided with a corresponding pad of the pad array 14. The second insulating layer is provided with a third electrode hole 10. The third electrode hole 10 is used to expose the first recording electrode 41. The third base layer is connected to the first base layer 5 to form an integrated structure. The fourth base layer is connected to the second base layer 7 to form an integrated structure. The first insulating layer 16 is connected to the second insulating layer to form an integrated structure.

[0074] It should be noted that a fourth electrode hole is provided on the fourth base layer, so that the wire layer 6 can be connected to the first recording electrode 41 through the fourth electrode hole.

[0075] Optionally, when the pad array 14 is located at the bottom of the overall structure, a fourth base layer can be provided between the wire layer 6 and the first recording electrode 41, so as to isolate the pad array from the first recording electrode 41, and avoid direct conduction between other pads on the pad array 14 and the first recording electrode 41, thereby short-circuiting the second recording electrode 42; and because the pad array is provided at the bottom, the corresponding top can also be provided with a recording electrode 4, so as to further effectively utilize the surface of the brain electrode and increase the number of channels for signal acquisition.

[0076] In a feasible embodiment, each of the N substructures 31 includes a first substrate layer 5, a wire layer 6, a second substrate layer 7, a recording electrode layer and a first insulating layer 16 stacked in sequence, a first electrode hole 71 is provided on the second substrate layer 7, and the wire layer 6 is connected to the recording electrode 4 of the recording electrode layer through the first electrode hole 71, and a second electrode hole 91 is provided on the insulating layer 16, and the second electrode hole 91 is used to expose the recording electrode 4, and the first substrate layer 5 of any substructure 31 of the N substructures 31 is provided with a through hole array, and each through hole in the through hole array is provided with a corresponding pad of the pad array 14. In other words, the pad array 14 is located on any substructure 31, and of course, the recording electrode 4 is provided on the first structure 101.

[0077] It should be noted that, although the recording electrodes 4 are not distinguished in the above description, it should be known that the number of recording electrodes 4 is the same as the number of pads in the pad array 14 and they are connected one-to-one, and a recording electrode 4 may be provided on each substructure 31.

[0078] Subsequently, the foldable brain electrode structure can be shaped using silk protein solution to form a ball, and after being implanted in the body and reaching the designated signal collection point, the protein can be dissolved in the body fluid environment to restore flexibility, making the brain electrode structure 1 highly flexible, foldable, and conformally adherent, with good operability, and capable of high-precision minimally invasive detection of electrical signals in deep brain nuclei.

[0079] By attaching the above-mentioned foldable brain electrode structure to curved surfaces of different curvatures, the flexible electrode device can be tightly attached to the curved surface using only the surface tension of water; the device can be folded into a ball under the action of external force, and the conductive performance of the device is not affected during this process. Figure 8 , Figure 8 The structure and stress distribution diagram of arc surfaces of different radii formed by the foldable brain electrode structure provided in this application. Figure 8 Figure a1 in the figure is a schematic diagram of the structure of the brain electrode structure 1 with a curved surface radius of 2.5 mm. Figure 8 Figure a2 in is the stress distribution diagram of Figure a1; Figure 8 Figure b1 in the figure is a schematic diagram of the structure of the brain electrode structure 1 with a curved surface radius of 5 mm. Figure 8 Figure b2 in is the stress distribution diagram of Figure b1; Figure 8 Figure c1 in the figure is a schematic diagram of the structure of the brain electrode structure 1 with a curved surface radius of 20 mm. Figure 8 Figure c2 is a stress distribution diagram of Figure c1; from this, it can be seen that the brain electrode structure 1 provided by the present application has less stress concentration, and as the radius of curvature increases, that is, the brain electrode structure 1 unfolds, the area of ​​high stress concentration of the structure gradually decreases.

[0080] Optionally, the brain electrode structure 1 disclosed in the present application can be applied to the detection of a wide range of EEG signals in neuroscience research and signal collection related to cutting-edge technology and artificial intelligence due to its foldability. It is designed for deep brain nuclei of the hypothalamus, and its special contour design can conform to the curved surface; the slender signal transmission circuit board is matched with mature craniopharyngioma surgery; the flexible skull base electrode combined with silk protein solution can be temporarily shaped before implantation, and after being implanted in the body and reaching the designated signal collection point, the protein is dissolved in the body fluid environment to restore flexibility; it can achieve high-precision minimally invasive detection of electrical signals in deep brain nuclei.

[0081] See also Fig. 9 , Fig. 9 This is a flow chart of an optional preparation of a brain electrode structure of the present application. In another aspect, the present application also discloses a method for preparing a brain electrode structure 1, which comprises:

[0082] 1) Provide a silicon substrate 11, such as Fig. 9 As shown in Figure (a).

[0083] 2) Prepare a sacrificial layer 12 on the silicon substrate 11, such as Fig. 9 As shown in Figure (b).

[0084] Optionally, the material of the sacrificial layer 12 includes aluminum, and the thickness ranges from 8000 to 10000 angstroms; optionally, the thickness of the sacrificial layer 12 is 1 micron.

[0085] 3) A support layer 13 is prepared on the sacrificial layer 12 .

[0086] Optionally, step 3) may be specifically described as: a flexible material layer may be formed on the sacrificial layer 12 by a spin coating process, and the flexible material layer may be patterned to form the support layer 13 .

[0087] Optionally, the flexible material layer comprises polyimide.

[0088] Optionally, after the above-mentioned flexible material layer is spin-coated, it is also required to be cured at a preset temperature.

[0089] Optionally, the curing temperature is 200 degrees Celsius.

[0090] 4) The conductor layer 6 and the recording electrode layer are formed on the support layer 13 in sequence.

[0091] Optionally, the preparation process may be different depending on the structural design. Figure 4 or Figure 5The structure of the substrate 13 can be specifically represented as follows: patterning a through hole array on the support layer 13; sputtering to form a pad array 14 at the through hole array; and then sequentially forming a wire layer 6 and a recording electrode layer. The wire layer 6 is a wire connecting the recording electrode 4 and the bottom pad array 14.

[0092] Optionally, the wire layer 6 and the recording electrode layer may be formed by a magnetron sputtering process.

[0093] Optionally, if prepared as Figure 6 The structure shown in FIG. 1 is a structure in which the support layer 13 is determined as the support layer 13. Then, step 4) can be represented as: patterning a through hole array on the layer, and sputtering to form a pad array 14 (such as Fig. 9 ), and sputtering forms a conductor layer 6 (as shown in FIG. Fig. 9 A flexible material layer is formed on the conductor layer 6 by a spin coating process, and the flexible material layer is patterned to obtain a packaging layer 15, and a second electrode hole 91 is formed on the packaging layer 15 (as shown in FIG. Fig. 9 As shown in FIG. (f) in FIG. 1 , a recording electrode layer is sputtered on the packaging layer 15; the wire layer 6 is connected to the recording electrode layer through the second electrode hole 91 (as shown in FIG. Fig. 9 as shown in Figure (g) in the figure).

[0094] Optionally, the material of the pad array 14 includes Cr / Au / Cr or Cr / Ni / Au / Cr, wherein the thickness of the sputtered Au layer ranges from 350 to 5000 angstroms, the thickness of the sputtered Ni layer ranges from 1000 to 1500 angstroms, and the thickness of the sputtered Cr layer ranges from 300 to 500 angstroms.

[0095] Optionally, the thickness of the support layer 13 is 2-3 micrometers.

[0096] Optionally, the thickness of the encapsulation layer 15 is in the range of 1 to 2 micrometers, and the curing temperature is in the range of 240 to 260 degrees Celsius.

[0097] Optionally, the materials of the wire layer 6 and the recording electrode layer include Cr / Au, and for the wire layer 6, the thickness of the Cr / Au material ranges from 300 / 3500 angstroms to 500 / 5000 angstroms, and for the recording electrode layer, the thickness of the Cr / Au material ranges from 300 / 3000 angstroms to 500 / 5000 angstroms.

[0098] 5) forming an insulating layer 16 on the recording electrode layer, such as Fig. 9 As shown in Figure (h).

[0099] Optionally, the material of the insulating layer 16 is the same as that of the base layer, both of which are flexible materials.

[0100] Optionally, the thickness of the insulating layer 16 is in the range of 5 to 8 micrometers, and the temperature for curing the flexible material layer is in the range of 280 to 320 degrees Celsius.

[0101] 6) Patterning and etching the insulating layer 16 to form electrode holes; the electrode holes can expose the recording electrode 4 of the recording electrode layer, such as Fig. 9 As shown in Figure (i) in .

[0102] 7) Release the sacrificial layer 12 to obtain the brain electrode structure 1 (such as Fig. 9 As shown in FIG. (g), the electrode structure 1 includes a first structure 101 and a second structure 3, and the recording electrode 4 is provided on the second structure 3; the second structure 3 includes N substructures 31; N is an integer greater than or equal to 2; there is a preset distance between adjacent substructures 31 in the N substructures 31, so that the N substructures 31 can gather toward the center of the first structure 101 to form an arc surface; the N substructures 31 are arranged around the edge of the first structure 101, which can be referred to Figure 7 .

[0103] It should be noted that during the preparation process, a metal connection layer (such as Fig. 9 As shown in Figure (d) in the figure, a metal connection layer is also sputtered in the first electrode hole 71 connecting the wire layer 6 with the upper recording electrode 4. The metal connection layer can be Cr / Au, and the thickness of the Cr / Au material ranges from 300 / 3500 angstroms to 500 / 5000 angstroms.

[0104] In a feasible embodiment, after releasing the sacrificial layer 12 and obtaining the brain electrode structure, the method further includes:

[0105] 8) The brain electrode structure 1 is placed in the inner cavity of the arc-shaped mold.

[0106] Optional, see Fig.10 , Fig.10 Schematic diagram of the structure of the arc-shaped mold. The mold with spherical hollow grooves can be made using polydimethylsiloxane (PDMS).

[0107] The brain electrode structure 1 is assembled with the flexible circuit board at the rear end, and the assembled device is placed in the mold so that the brain electrode structure is completely attached to the inner wall of the spherical cavity.

[0108] 9) Pour the silk protein solution into the inner cavity.

[0109] Optionally, the silk protein solution can be prepared by the following method: the silkworm cocoons are boiled in a 0.02 mol / L Na2CO3 aqueous solution for 30 minutes, and then rinsed with distilled water 3 times (30 minutes each time) to remove Na2CO3 and sericin. After drying in air for about 12 hours, the degummed cocoons are dissolved in a 9.3 mol / L LiBr solution at 60°C for about 4 hours. The solution is dialyzed for 2 days using a Slide-A-Lyzer dialysis cassette (molecular weight cutoff, MWCO=3500, Pierce, USA). Subsequently, centrifugation is performed twice at 18000 rpm, each time for 20 minutes. By measuring the volume and final dry weight of the solution, it is determined that the final concentration of silk is about 6-7wt%.

[0110] Optionally, the concentration of the silk protein solution may also be in the range of 7 to 15 wt %. The concentration of the shaping solution only affects the length of time it takes for the flexible electrode to recover its flexibility after the dissolved protein is in the body fluid environment.

[0111] 10) After drying, take it out to obtain a folded and solidified brain electrode structure 1.

[0112] It should be noted that by pouring the above-mentioned silk protein solution into the mold and drying it in a clean room environment for 24 hours; after demolding, the front end brain electrode structure can be shaped into a small ball with a radius of about 4 mm (depending on the mold radius, the optional range is 3 to 5 mm).

[0113] The flexible skull base electrode made according to the above manufacturing process is attached to curved surfaces of different curvatures. The flexible electrode device can be tightly fitted to the curved surface simply by using the surface tension of water; the device can be folded into a ball under the action of external force, and the conductive performance of the device is not affected in this process.

[0114] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A front end structure of an electroencephalogram electrode, characterized in that: include: A brain electrode structure (1), the brain electrode structure (1) being used for collecting signals from brain tissue; the brain tissue being away from the parietal lobe; a flexible connector (2), one end of the flexible connector (2) being connected to the brain electrode structure (1), and the other end of the flexible connector (2) being connected to a signal processing device; the length of the flexible connector (2) being greater than or equal to a preset length, so that the flexible connector (2) can approach the brain tissue through the nasal cavity; The brain electrode structure (1) comprises a first structure (101) and a second structure (3), wherein the second structure (3) is provided with a recording electrode (4); the second structure (3) comprises N substructures (31); N is an integer greater than or equal to 2; there is a preset distance between adjacent substructures (31) in the N substructures (31), so that the N substructures (31) can gather toward the center of the first structure (101) to form an arc surface; the N substructures (31) are arranged around the edge of the first structure (101); Each of the N substructures is provided with a recording electrode (4); The brain electrode structure (1) is placed in a silk protein solution and folded to form a spherical structure; A pad array (14) is provided on the top of the first structure (101) or on any one of the N substructures (31); The pad array (14) is connected correspondingly to the pad structure of the external connection structure.

2. The front end structure of the brain electrode according to claim 1, characterized in that: The recording electrode (4) and the pad array (14) are located on the same plane; Each substructure (31) in the remaining substructures (31) of the N substructures (31) comprises a first base layer (5), a wire layer (6) and a first insulating layer (9) stacked in sequence; The wire layer (6) comprises wires and the recording electrodes (4); One end of the wire is connected to the recording electrode (4), and the other end of the wire is connected to a corresponding pad in the pad array (14); The first insulating layer (9) is provided with an electrode hole for exposing the recording electrode (4).

3. The front end structure of the brain electrode according to claim 1, characterized in that: The pad array (14) is provided at the bottom of the first structure (101); The recording electrode (4) comprises a first recording electrode (41) and a second recording electrode (42); The first recording electrode (41) is provided on the top of the first structure (101); Each of the N substructures (31) comprises a first substrate layer (5), a wire layer (6), a second substrate layer (7), a second recording electrode layer (8) and a first insulating layer (9) stacked in sequence; The second substrate layer (7) is provided with a first electrode hole (71), and the wire layer (6) is connected to the second recording electrode (42) of the second recording electrode layer (8) through the first electrode hole (71); A second electrode hole (91) is provided on the first insulating layer (9), and the second electrode hole (91) is used to expose the second recording electrode (42); The first structure (101) comprises a third base layer, a fourth base layer and a second insulating layer; The third base layer is provided with a through hole array; Each through hole in the through hole array is provided with a corresponding solder pad of the solder pad array (14); A third electrode hole (10) is provided on the second insulating layer, and the third electrode hole (10) is used to expose the first recording electrode (41); The third base layer is connected to the first base layer (5) to form an integrated structure; The fourth base layer and the second base layer (7) are connected to form an integral structure; The first insulating layer (9) and the second insulating layer are connected to form an integral structure.

4. The front end structure of the brain electrode according to claim 1, characterized in that: Each of the N substructures (31) comprises a first substrate layer (5), a wire layer (6), a second substrate layer (7), a recording electrode layer and a first insulating layer (9) stacked in sequence; The second substrate layer (7) is provided with a first electrode hole (71), and the wire layer (6) is connected to the recording electrode (4) of the recording electrode layer through the first electrode hole (71); A second electrode hole (91) is provided on the first insulating layer (9), and the second electrode hole (91) is used to expose the recording electrode (4); The first base layer (5) of any one of the N substructures (31) is provided with a through-hole array; Each through hole in the through hole array is provided with a corresponding solder pad of the solder pad array (14).

5. The front end structure of the brain electrode according to claim 1, characterized in that: The shape of the second structure (3) includes a triangle, a quadrilateral, a pentagon or a hexagon.

6. The front end structure of the brain electrode according to claim 1, characterized in that: The second structure (3) includes M first substructures (311) and NM second substructures (312); M is an integer greater than or equal to 1; The M first substructures (311) are arranged along the edge of the first structure (101) and connected to the edge of the first structure (101); The NM second substructures (312) are arranged along the outer edges formed by the M first substructures (311), and each second substructure (312) among the NM second substructures (312) is connected to the corresponding first substructure (311).

7. The front end structure of the brain electrode according to claim 1, characterized in that: The flexible connection includes a flexible circuit board.

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