Brain-computer interface microarray electrode capable of being applied to special silent communication

Abstract

The invention provides a brain-computer interface microarray electrode capable of being applied to special silent communication, the microarray electrode comprises a microneedle array structure, and a conductive coating layer is arranged on the surface of the microneedle array structure; the overall size of the microneedle array structure is smaller than or equal to 1 mm, the weight of the microneedle array structure is smaller than or equal to 0.5 g, and the array arrangement form of the microneedle array structure is selected from one of a cross shape, a square shape, a hexagon shape and a circle shape. The microneedles of the microneedle array structure are selected from one of a conical structure, a polygonal pyramid structure or a stepped structure; and the conductive coating layer is a PEDOT (poly (3, 4-ethylenedioxythiophene)): Tos conductive coating layer. The electrode can realize breakthrough design in miniaturization and portability. The weight of the microneedle is controlled within 0.5 g, the harsh requirements of hidden wearing and long-term carrying in special tasks can be met, and the microneedle is used for solving the problems in the prior art.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of brain-computer interface micro-needle electrode, and particularly relates to a brain-computer interface micro-array electrode applicable to special silent communication. BACKGROUND

[0002] Brain-computer interface technology is a technology for establishing a real-time communication and control system between the brain and external devices or the environment, and can realize direct interaction between the brain and external devices. Brain-computer interface technology involves multiple key research fields, which aim to solve problems at different levels and have made breakthroughs in recent years. First, signal sensing and acquisition, which mainly solves how to obtain brain signals, generally electrical signals generated by brain neurons, with high fidelity and stability. Second, device miniaturization and portability, which aims to improve user experience and expand application scenarios, making brain-computer interface devices more portable, easy to wear and use, so as to be widely used in daily life, medical treatment, military and other scenarios. In addition, there is brain signal encoding and decoding algorithm, which is committed to realizing accurate conversion of brain signals and external device control instructions.

[0003] Driven by technological innovation in the fields of sensing and acquisition, portable equipment, encoding and decoding algorithms, brain-computer interface has shown excellent application prospects in many fields. The most mature and core is the medical rehabilitation field, which plays a prominent role in motor function reconstruction and assistance, communication and expression, neurological disease diagnosis and monitoring, and rehabilitation training. Among them, the most typical is to bring new hope to paralyzed patients through brain-computer interface. Paralyzed patients can convert brain signals into control instructions and realize autonomous movement and daily activities with the help of external assistive devices such as intelligent wheelchairs and mechanical arms, thereby improving self-care ability and quality of life. The most advanced technology is often applied in the military field first, and brain-computer interface is no exception. In terms of improving soldiers' combat capabilities, brain-computer interface can realize real-time interaction between all-around battlefield information and soldiers' brains. For example, through brain-controlled weapons, soldiers can accurately and efficiently control unmanned equipment such as drones, and even realize one-man multi-control, greatly improving combat effectiveness. The silent communication function can enable soldiers to communicate silently in covert operations or harsh environments, avoiding exposure.

[0004] The premise of brain-computer interface technology is to establish a stable low impedance interface between the brain and the electrode to ensure the quality of the brain electrical signal. No matter what kind of electrode is used, the basic idea is to improve the quality of the EEG recorded signal while improving the comfort of the patient and minimizing the trauma to the patient. Therefore, the development of non-invasive electrodes or will become the key driving force for the next generation of BCI technology. The wet electrode, gel electrode, dry electrode and other traditional non-invasive brain-computer interfaces will inevitably produce motion noise, reduce signal quality, reduce the efficiency of brain-computer encoding and decoding, and cause problems such as poor accuracy of downstream task execution. The existing brain-computer interface electrodes have the following two disadvantages: first, the traditional electrode is large in size and heavy in weight, and the inertia during movement causes the electrode to displace and produce noise; second, the traditional electrode is deployed on the electrode cap and the like base, and uses a hard wire, which will inevitably produce noise during movement. The above two disadvantages become the key obstacles to the application of brain-computer interface electrodes in special silent communication. Therefore, the development of brain-computer electrodes with miniaturization, high anti-interference, motion robustness and wearing comfort is becoming the core research and development trend at this stage. SUMMARY

[0005] In view of the above-mentioned disadvantages of the prior art, the purpose of the present application is to provide a brain-computer interface microarray electrode applicable to special silent communication, which will achieve a breakthrough design in miniaturization and portability. The weight of the microneedle is controlled to be less than 0.5g, which can meet the strict requirements of hidden wearing and long-term carrying in special tasks, and is used to solve the problems in the prior art.

[0006] The technical scheme of the present application is:

[0007] In one aspect, the present application provides a brain-computer interface microarray electrode applicable to special silent communication, which comprises a microneedle array structure, and a conductive coating layer is arranged on the surface of the microneedle array structure; the overall size of the microneedle array structure is ≤1mm, and the weight is ≤0.5g; the array arrangement form of the microneedle array structure is selected from one of a cross shape, a square shape, a hexagonal shape or a circular shape; the microneedle of the microneedle array structure is selected from one of a conical structure, a multi-prism structure or a stepped structure; and the conductive coating layer is a PEDOT:Tos conductive coating layer.

[0008] In another aspect, the present application provides a preparation method of a brain-computer interface microarray electrode applicable to special silent communication, which comprises the following steps:

[0009] 1) mixing an iron p-toluenesulfonate solution with 3,4-ethylenedioxythiophene to prepare a conductive precursor solution;

[0010] 2) directly engraving the arrangement form of the microneedle array by using a two-photon lithography technology to obtain a microneedle array structure;

[0011] 3) The conductive precursor solution is uniformly coated onto the surface of the microneedles using vertical spin coating technology, followed by heat treatment to initiate a polymerization reaction. After the reaction, the microneedles are cleaned and dried to form a PEDOT:Tos conductive coating layer on the surface of the microneedles, thus obtaining a microarray electrode.

[0012] By adopting the aforementioned technical solution, the beneficial effects of the present invention are:

[0013] (1) Miniaturized structure design The overall size of the miniature non-invasive electrode is ≤1mm and the weight is ≤0.5g. It can be hidden in the gap between hair follicles and under hair on the human scalp, and has excellent concealment, meeting the wearing requirements in special silent communication scenarios.

[0014] (2) The electrode acquisition end of the microneedle array is equipped with a microneedle array structure. The tip size of the microneedle is precisely matched with the physical characteristics of the scalp stratum corneum. It can penetrate the scalp surface stratum corneum non-invasively, shorten the contact distance between the electrode and the subcutaneous active tissue, effectively reduce the contact resistance of the electrode-skin interface, and improve the efficiency of EEG signal acquisition.

[0015] (3) The stable attachment mechanism is based on the mechanical interlocking of the microneedle array with the skin texture around the hair follicle, combined with the adhesion characteristics of the flexible electrode substrate, to achieve stable fixation of the electrode on the scalp surface, avoiding the signal drift problem caused by the sliding of the traditional electrode on the body surface, and ensuring the stability of signal acquisition.

[0016] (4) The electrodes of the elastic serpentine wire connection structure are connected by an elastic serpentine wire. The serpentine wire has excellent tensile and bending resistance. When the human body moves violently or the head posture changes significantly, it can buffer the external force through its own deformation to prevent the electrodes from being displaced or falling off due to the pulling of the wire. At the same time, it suppresses the mechanical motion noise caused by the vibration and pulling of the wire and enhances the acquisition quality of the original EEG signal.

[0017] This invention achieves concealed wearing, stable fixation, and high-quality signal acquisition of EEG electrodes through the synergistic design of miniaturization, microneedle penetration, stable attachment, and anti-traction wires. It effectively solves the technical pain points of traditional non-invasive electrodes, such as high contact resistance, large motion noise, and poor concealment, and provides stable and reliable signal input support for special silent communication. Attached Figure Description

[0018] Figure 1 The diagram shows the fabrication process of the brain-computer interface microarray electrode that can be applied to special silent communication according to the present invention;

[0019] Figure 2 This diagram illustrates the technical roadmap for the brain-computer interface microarray electrodes of this invention, which can be applied to specialized silent communication. Detailed Implementation

[0020] The following describes in detail the embodiments of the brain-computer interface microarray electrodes that can be applied to special silent communication provided by the present invention.

[0021] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0022] Silent communication based on brain-computer interfaces refers to a communication method that encodes and transmits information directly through brain activity without producing sound, making obvious physical movements, or operating traditional electronic devices. Its core advantages are prominent, mainly revolving around "concealment" and "interference resistance," making it particularly suitable for highly sensitive, high-risk, or extreme environments. Its main advantages include: extreme concealment and low observability; excellent environmental adaptability and interference resistance; enhanced security and confidentiality; improved personnel efficiency and collaboration; and providing communication possibilities for special populations.

[0023] However, it is worth noting that the development of brain-computer interface-based battlefield silent communication systems still faces many challenges and is some distance from practical battlefield application. These challenges manifest in three main aspects, and this project will focus its research on these three areas: 1. Regarding EEG signal sensing electrodes, traditional macroscopic electrodes such as wet electrodes, dry electrodes, and gel electrodes are relatively large and heavy. Due to inertia and the pull of the leads, they are prone to motion noise, which negatively impacts brain-computer encoding and decoding. 2. Regarding brain-computer encoding and decoding, although the SSVEP brain-computer interface paradigm can achieve the highest brain-computer information transmission rate, it relies on visual stimulation provided by devices such as displays, making wearable portability impossible. 3. Regarding distributed communication networks, brain-computer commands in "silent communication" still need to be transmitted via electromagnetic wave-based wireless communication. However, the battlefield environment lacks fixed infrastructure and is characterized by its variability, complexity, and high mobility.

[0024] Through extensive research and exploration, the inventors of this invention have developed a brain-computer interface microarray electrode applicable to special silent communication scenarios. This invention focuses on the core pain points of non-invasive electrodes in special silent communication scenarios, and systematically innovates from three dimensions: design and synthesis of highly conductive coating materials, optimization of microneedle array structure for dynamic bonding, and development of uniform coating process for conductive layer on microneedle surface, thus breaking through the performance bottleneck of traditional electrodes in all aspects. Regarding highly conductive coating materials, the shortcomings of traditional PEDOT:PSS materials in terms of insufficient conductivity are overcome. A highly conductive polymer, PEDOT:Tos, with a conductivity ≤900 S / cm, is selected. Through precise formulation of the precursor solution (e.g., a 20:1 volume ratio of 40 wt.% ferric p-toluenesulfonate solution to 3,4-ethylenedioxythiophene) and optimized heat treatment processes, a low-resistance, high-adhesion conductive coating is formed, laying the core foundation for reducing contact resistance. In terms of microneedle array structure optimization, not only is the overall electrode size strictly controlled to ≤1mm and the weight ≤0.5g, allowing it to be cleverly concealed within the hair follicle gap (adapting to the physiological characteristic of hair follicle spacing <1mm) and under the hair, but also through "mechanical interlocking + bio-adhesion"... A dual-design approach enhances stable adhesion: Structurally, the microneedle taper (e.g., 15°~25°, more specifically 19°), tip curvature (e.g., 2~5μm, more specifically 3μm), and array arrangement (e.g., hexagonal) are optimized to ensure tight embedding into the skin texture and physical bonding. Materially, a biocompatible adhesive functional layer is added to achieve a gentle yet firm bond with the epidermis, completely resolving the issue of displacement inherent in traditional electrodes. In terms of coating technology, an innovative vertical spin-coating technique, combined with an electrochemical deposition backup solution, overcomes the challenge of uniformly covering micron-level curved conductive layers, while simultaneously strengthening the interfacial adhesion between the conductive layer and the substrate, ensuring long-term use without detachment. Compared to traditional non-invasive electrodes, this effectively reduces contact resistance, improves battery life, and provides stable adhesion, hiding between hair follicles and under the hair. Connected by a flexible serpentine wire, it is not easily pulled or dragged, suppressing motion noise and enhancing the original signal quality. Based on these principles, this application was completed.

[0025] Brain-computer interface microarray electrodes applicable to specialized silent communication

[0026] The present invention provides a brain-computer interface microarray electrode that can be applied to special silent communication. The microarray electrode includes a microneedle array structure, and the surface of the microneedle array structure is provided with a conductive coating layer.

[0027] The microarray electrodes for brain-computer interfaces provided by this invention, applicable to specialized silent communication, feature an optimized microelectrode structure. The size of the microelectrodes, the number of microneedles, and the array arrangement all affect connection and signal stability. The microneedle array structure is designed based on the physiological characteristic of human hair follicle spacing ≤1mm. Appropriate microelectrode sizes and shapes are designed based on this dimension to avoid pressing on the hair and affecting wear, while ensuring a suitable shape allows the electrodes to be inserted into the tiny gaps between hair follicles. The overall size of the microneedle array structure is ≤1mm, for example, 0.01~1mm, 0.01~0.1mm, 0.1~0.5mm, 0.5~1mm, etc., where size refers to side length or diameter. The weight is ≤0.5g, for example, 0.01~0.5g, 0.01~0.1g, 0.1~0.5g, etc.

[0028] The microarray electrodes for brain-computer interfaces provided by this invention, applicable to specialized silent communication, feature a microneedle array structure arranged in a cross, square, hexagonal, or circular pattern. For example, various microneedle array arrangements can be directly etched using Nano Scribe laser direct-write lithography.

[0029] Preferably, the microneedle array structure is arranged in a hexagonal pattern, which is adapted to the distribution characteristics of hair follicles. When worn, there is no pressure from hair, and the concealment meets the requirements of special silent communication scenarios.

[0030] The microneedles of the microneedle array structure are selected from one of the following: conical structure, multi-faceted pyramidal structure, or stepped structure. Wherein:

[0031] The taper of the conical structure is 15°~25°, and can be selected as 15°~20° or 20°~25°. The tip curvature is 2~5μm, and can be selected as 2~3μm or 3~5μm.

[0032] The multi-faceted pyramid structure is a 3-4 faceted pyramid with acute angles on the edges, such as 15° to 25°. The sharp angles reduce the puncture resistance by 30% compared to conical microneedles.

[0033] The stepped structure has an upper taper of 18°~20°, which can be selected as 18°~19° or 19°~20°. The lower taper is 24°~26°, which can be selected as 24°~25° or 25°~26°, to enhance dynamic adhesion stability.

[0034] This invention provides a microarray electrode for a brain-computer interface applicable to special silent communication, exploring the effect of different numbers of microneedles on connection stability. The microneedle array structure described in this invention contains 3 to 6 microneedles. The spacing between adjacent microneedles is 200 to 500 μm, optionally 200 to 300 μm or 300 to 500 μm. The aspect ratio of the microneedles is 2.8 to 3.2:1, optionally 2.8 to 3.0:1 or 3.0 to 3.2:1, preferably 3:1. The needle length is 200 to 300 μm, optionally 200 to 250 μm or 250 to 300 μm, allowing for non-invasive penetration of the scalp's stratum corneum.

[0035] The micro-array electrode for brain-computer interface that can be applied to special silent communication provided by the present invention is made of dental resin, wherein the dental resin includes TEGDMA (triethylene glycol dimethacrylate) and DUDMA (diurea dimethacrylate). In a specific embodiment, the mass ratio of TEGDMA to DUDMA is (7~9):(1~3), preferably 8:2.

[0036] Compared to traditional molding methods for microneedle fabrication, Nano Scribe laser direct-write lithography offers advantages such as better precision and resolution, simplified and rapid iteration processes, shorter development time, improved development efficiency, and greater freedom in processing complex structures. Regarding the parameter structure and material selection for the microneedles, this invention will consider factors such as the strength of human scalp skin tissue, comprehensively selecting suitable materials, such as dental resin, and optimizing parameters such as the sharpness and diameter of the microneedles. Simulated puncture experiments will be used to observe whether the microneedles can successfully puncture the skin surface, form a tight connection, and not break or bend during puncture and withdrawal. Simultaneously, microscopes and other equipment will be used to observe skin damage after microneedle puncture and assess the biocompatibility of the microneedles.

[0037] The geometry, array arrangement, size parameters, and material selection of microneedle structures are the core factors determining the signal acquisition quality, wearing stability, biocompatibility, and scene adaptability of brain-computer interface electrodes. Two-photon lithography technologies, such as Nanoscribe laser direct writing lithography, offer key technical support for the precise fabrication and performance optimization of multi-dimensional microneedle structures compared to traditional casting methods, thanks to their advantages such as nanoscale resolution, high degree of freedom in processing complex structures, short R&D cycle, and strong material compatibility.

[0038] This technology can flexibly realize geometric variations such as solid conical microneedles (taper 15°~25°, tip curvature 2~5μm), multi-faceted pyramidal microneedles, and stepped microneedles, as well as array arrangement designs such as hexagonal, cross-shaped, and ring-shaped microneedles to adapt to hair follicle distribution (spacing <1mm). It also supports the integrated processing of functional composite structures such as grooved microneedles and porous microneedles. It not only solves the problems of dimensional deviation, edge blurring, and limited processing of complex configurations that are easy to occur in the replication of micron-level fine structures by traditional molding, but also can accurately control key parameters such as the aspect ratio and array density of microneedles through rapid parameter iteration. This allows the microneedles to meet the signal acquisition requirements of non-invasive penetration of the scalp stratum corneum (contact impedance density as low as 0.03 kΩ·cm²) and enhance dynamic adhesion stability through the structure-material co-design of "mechanical interlocking + bio-adhesion". Combined with the elastic serpentine interconnector, it effectively suppresses motion artifacts (classification accuracy reaches 96.4%). This collaborative model of "structural design-technical implementation-performance adaptation" not only breaks through the limitations of traditional fabrication techniques on microneedle structure innovation, but also, through the balance between personalized customization and batch consistency, enables the electrodes to precisely meet the core requirements of "concealment, low impedance, and long-term stability" in special silent communication scenarios, providing an important guarantee for the performance leap of brain-computer interface electrodes.

[0039] The present invention provides a brain-computer interface microarray electrode applicable to special silent communication, wherein the conductive coating layer is a PEDOT:Tos conductive coating layer, wherein PEDOT is poly(3,4-ethylenedioxythiophene) and Tos is p-toluenesulfonyl. PEDOT:Tos is a conductive polymer in which p-toluenesulfonate ions act as dopants and counterions, combining with the PEDOT backbone to form a conductive material. PEDOT:Tos material is superior to traditional PEDOT:PSS material in terms of conductivity and stability, and the preparation process is relatively simple.

[0040] In a specific embodiment, the PEDOT:Tos conductive coating layer is prepared by mixing 40 wt.% ferric p-toluenesulfonate solution with 3,4-ethylenedioxythiophene at a volume ratio of 20:1 to prepare a conductive precursor solution. This precursor solution is then uniformly coated onto the surface of a resin film. After coating, a heat treatment at 80°C for 5 minutes initiates a polymerization reaction, promoting the polymerization of PEDOT and Tos. Next, the film is washed sequentially with isopropanol and deionized water to remove unreacted precursor solution and byproducts. Finally, it is dried overnight at 80°C to form a robust PEDOT:Tos conductive coating layer.

[0041] The PEDOT:Tos conductive coating layer provided by this invention has a conductivity ≤900 S / cm, which can be selected as 100-900 S / cm, 100-600 S / cm, 600-900 S / cm, 600-700 S / cm, 700-900 S / cm, 700-800 S / cm, or 800-900 S / cm.

[0042] The brain-computer interface microarray electrode provided by this invention, which can be applied to special silent communication, has a cell survival rate of ≥95% in the conductive coating layer, and a conductivity stability fluctuation of ≤10% in an environment with a temperature of -10℃ to 45℃ and a humidity of 30% to 80%.

[0043] The micro-array electrode for brain-computer interface provided by this invention, which can be applied to special silent communication, adopts a dual fixation mechanism of "mechanical interlocking + bio-adhesion". The surface of the microneedles of the micro-needle array structure is modified with a biocompatible adhesive functional layer. A conductive coating layer is provided on the biocompatible adhesive functional layer, which forms a physical lock and interfacial adhesive bond with the skin texture around the hair follicle.

[0044] The brain-computer interface microarray electrode provided by this invention can be applied to special silent communication. It does not bend or break during puncture / removal, and there is no obvious damage to the skin tissue after puncture.

[0045] The microarray electrodes for brain-computer interfaces provided by this invention, which can be applied to special silent communication, are connected to adjacent microarray electrodes by an elastic serpentine interconnect. The elastic serpentine interconnect is made of polyimide / copper bilayer material, which can be stretched to 250% elongation and has no change in resistance after 10,000 cycles of tensile testing.

[0046] [Preparation method of brain-computer interface microarray electrodes applicable to specialized silent communication]

[0047] This invention also provides a method for fabricating a brain-computer interface microarray electrode applicable to special silent communication, combined with... Figure 1 and Figure 2 The preparation method includes the following steps:

[0048] 1) A conductive precursor solution was prepared by mixing ferric p-toluenesulfonate solution with 3,4-ethylenedioxythiophene.

[0049] 2) The arrangement of the microneedle array is directly etched using two-photon lithography to obtain the microneedle array structure;

[0050] 3) The conductive precursor solution is uniformly coated onto the surface of the microneedles using vertical spin coating technology, followed by heat treatment to initiate a polymerization reaction. After the reaction, the microneedles are cleaned and dried to form a PEDOT:Tos conductive coating layer on the surface of the microneedles, thus obtaining a microarray electrode.

[0051] In the preparation method provided by this invention, step 1) involves mixing ferric p-toluenesulfonate solution with 3,4-ethylenedioxythiophene to prepare a conductive precursor solution. Specifically:

[0052] In step 1) of the present invention, the volume ratio of the iron p-toluenesulfonate solution to 3,4-ethylenedioxythiophene is 18~22:1, and can be selected as 18~20:1 or 20~22:1.

[0053] In step 1) of the present invention, the concentration of the ferric p-toluenesulfonate solution is 30-50 wt.%, and can be 30-40 wt.% or 40-50 wt.%.

[0054] In the preparation method provided by this invention, step 2) uses two-photon lithography to directly etch the arrangement of the microneedle array, thus obtaining the microneedle array structure. Specifically:

[0055] a: Two-photon 3D printing:

[0056] Manually applying photoresist (IP-S) to a substrate (such as glass or silicon wafer) to a thickness exceeding 500 micrometers; 3D printing;

[0057] b: Pour the resin (dental resin: TEGDMA and DUDMA) into the mold and UV mold (5~7W, 400~410nm, 3~7min):

[0058] c: High-precision laser cutting.

[0059] Two-photon lithography techniques can be, for example, Nano Scribe laser direct-write lithography.

[0060] In step 2) of this invention, personalized processing is achieved through two-photon lithography technology. The microneedle position and array parameters are customized according to the hair follicle distribution data of different populations, and the size consistency error of mass production is ≤±1%.

[0061] In the preparation method provided by this invention, step 3) involves uniformly coating the conductive precursor solution onto the surface of the microneedles using a vertical spin-coating technique, followed by heat treatment to initiate a polymerization reaction. After the reaction, the microneedles are cleaned and dried to form a PEDOT:Tos conductive coating layer, thus obtaining a microarray electrode. Specifically:

[0062] In step 3) of this invention, the vertical spin coating technology includes attaching a microneedle array to the side of the spin coating plate, dropping a conductive precursor solution onto the upper surface of the microneedles and then rotating to homogenize the solution, using centrifugation to make the upper surface of the microneedles uniformly covered with the solution, and then rotating the microneedle array structure 180° so that the lower surface faces upward, and repeating the operation. The amount of conductive precursor solution dropped in the two spin coatings is the same.

[0063] Furthermore, in the spin coating process, the rotation speed is 3900~4100rpm, which can be selected as 3900~4000rpm or 4000~4100rpm, and the spin coating time is 8~12 seconds, which can be selected as 8~10 seconds or 10~12 seconds.

[0064] In step 3) of this invention, during the vertical spin coating process, the error in the amount of precursor solution added is ≤ ±0.1 μL, ensuring the consistency of the coating thickness on the upper and lower surfaces of the microneedles.

[0065] In step 3) of the present invention, the temperature of the heat treatment is 60~100℃, which can be 60~80℃ or 80~100℃, and the heat treatment time is 3~7 minutes, which can be 3~5 minutes or 5~7 minutes.

[0066] In step 3) of this invention, the product is washed with isopropanol and deionized water in sequence.

[0067] In step 3) of this invention, the drying temperature is 60~100℃, which can be selected as 60~80℃ or 80~100℃, and the drying time is 24H.

[0068] In a specific embodiment, the conductive layer coating process adopts vertical spin coating technology, in which the microneedle array structure is fixed on the side of the spin coating plate, and spin coating is performed at 4000 rpm for 10 seconds. After being rotated 180°, the amount of precursor solution added is kept consistent and spin coating is repeated. After polymerization at 80°C and drying treatment, a uniform PEDOT:Tos conductive coating layer is formed.

[0069] The beneficial effects of the present invention will be further illustrated below with reference to the embodiments.

[0070] To make the inventive objectives, technical solutions, and beneficial effects of this invention clearer, the invention is further described in detail below with reference to embodiments. However, it should be understood that the embodiments of this invention are merely for illustrative purposes and not for limiting the invention, and the embodiments are not limited to those given in the specification. Unless otherwise specified, specific experimental or operational conditions in the embodiments were prepared under conventional conditions or according to the conditions recommended by the material supplier.

[0071] Furthermore, it should be understood that the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, does not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. It should also be understood that the combined connection relationship between one or more devices / apparatus mentioned in this invention does not preclude the existence of other devices / apparatus before or after the combined devices / apparatus, or the insertion of other devices / apparatus between these explicitly mentioned devices / apparatus, unless otherwise stated. Moreover, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or limiting the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0072] In the following embodiments, unless otherwise specified, all the raw materials of the present invention are commercially available or prepared according to conventional methods in the art.

[0073] Example 1

[0074] PEDOT: Tos conductive coating

[0075] A conductive precursor solution was prepared by mixing 40 wt.% ferric p-toluenesulfonate solution with 3,4-ethylenedioxythiophene at a volume ratio of 20:1. This solution was then uniformly coated onto the surface of a resin film. After coating, heat treatment at 80°C for 5 minutes initiated a polymerization reaction, promoting the polymerization of PEDOT and Tos. Subsequently, the film was washed sequentially with isopropanol and deionized water to remove unreacted precursor solution and byproducts. Finally, it was dried overnight at 80°C to form a robust PEDOT:Tos conductive coating.

[0076] After the materials are prepared, they need to be systematically tested.

[0077] For thickness measurement, an electron scanning microscope was used to measure the coating thickness. By measuring the thickness at different locations multiple times, the average thickness was calculated to evaluate the uniformity of the coating. Specific testing methods were performed according to GB / T 16594-2008.

[0078] Conductivity testing involves measuring the resistivity of a material to calculate its conductivity, and then conducting tests under different temperatures and humidity conditions to assess the stability of conductivity under varying conditions. Specific test methods are detailed in GB / T 41232.3-2023.

[0079] Impedance testing uses an impedance analyzer to measure the impedance values ​​of materials at different frequencies, plots impedance spectra, analyzes the impedance characteristics of the material at different frequencies, and evaluates its performance in signal transmission. Specific test methods are described in T / CAS976—2024.

[0080] The anti-detachment performance test involves fixing the prepared microelectrode material onto the surface of simulated skin, applying different tensile forces, observing whether the coating detaches, and recording the maximum tensile force that the coating can withstand to evaluate its anti-detachment performance. Specific test methods are detailed in T / GXDSL 007-2025.

[0081] Example 2

[0082] 1) A conductive precursor solution was prepared by mixing 40 wt.% ferric p-toluenesulfonate solution with 3,4-ethylenedioxythiophene at a volume ratio of 20:1.

[0083] 2) a: Nano Scribe direct printing: Manual spin coating of photoresist IP-S onto a substrate, with a coating thickness exceeding 500 micrometers; 3D printing;

[0084] b: Pour the resin (dental resin: TEGDMA to DUDMA mass ratio 8:2) into the mold and UV mold (6W, 405nm, 5min):

[0085] c: High-precision laser cutting.

[0086] 3) A vertical spin-coating technique is employed. The microneedle array structure is attached to the side of a spin-coating plate. A conductive precursor solution is dropped onto the surface of the microneedles, and then spin-coated at 4000 rpm for 10 seconds. Centrifugation is used to ensure the solution is evenly distributed on the microneedle surface. The microneedle array is then rotated 180° so that the bottom surface faces upwards, and this process is repeated to ensure that the amount of precursor solution added in each spin-coating is consistent. After both sides of the microneedles are coated with the precursor solution, they are heat-treated at 80°C for 5 minutes to promote the polymerization reaction between PEDOT and Tos. The microneedles are then washed sequentially with isopropanol and water to remove unreacted precursor solution and byproducts. Finally, they are dried overnight at 80°C to form a PEDOT:Tos conductive coating layer on the microneedle surface, resulting in the microarray electrode.

[0087] Strength test (measuring the compressive strength of the microneedles by applying pressure, etc.). Specific test methods refer to GB15811-2016.

[0088] Adhesion test (measures the adhesion force between the conductive material and the surface of the microneedle). Specific test methods are as per GB / T 5270-2024.

[0089] Stability testing (observing performance changes of the microneedle array under different environments). Specific testing methods are detailed in T / GXDSL 010-2025.

[0090] Impedance testing (similar to the impedance testing method used in material performance inspection). Specific testing methods are detailed in T / CAS976—2024.

[0091] Bending resistance test (apply bending force to the microneedles and observe their bending performance). Specific test methods refer to YY / T0899-2020.

[0092] Flexural strength test (apply flexural force to the microneedles and evaluate their flexural strength). Specific test methods are as per YY / T 0899-2020.

[0093] In the design of the microelectrode structure, taking into account the size of human hair follicles and combining various microneedle array arrangements and parameter optimizations, a balance between wearing comfort and signal stability can be effectively achieved. Mouse skin simulation experiments provide a reliable model for verifying the structural performance, while in-depth research on microneedle materials and parameters can ensure the safety and stability of microneedles when puncturing the skin, reducing the risk of use.

[0094] In summary, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0095] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A brain-computer interface microarray electrode applicable to special silent communication, characterized in that, The microarray electrode includes a microneedle array structure, and the surface of the microneedle array structure is provided with a conductive coating layer. The overall size of the microneedle array structure is ≤1mm, and the weight is ≤0.5g. The array arrangement of the microneedle array structure is selected from one of the following: cross, square, hexagon, or circle. The microneedles of the microneedle array structure are selected from one of the following: conical structure, multi-faceted pyramidal structure, or stepped structure. The conductive coating is a PEDOT:Tos conductive coating.

2. The brain-computer interface microarray electrode applicable to special silent communication according to claim 1, characterized in that, The microneedle array structure is arranged in a hexagonal pattern.

3. The brain-computer interface microarray electrode applicable to special silent communication according to claim 1, characterized in that, The microneedle array structure contains 3 to 6 microneedles, with a spacing of 200 to 500 μm between adjacent microneedles, a length-to-diameter ratio of 2.8 to 3.2:1, and a needle body length of 200 to 300 μm.

4. The brain-computer interface microarray electrode applicable to special silent communication according to claim 1, characterized in that, It also includes one or more of the following conditions: A1) The taper of the conical structure is 15°~25° and the needle tip curvature is 2~5μm; A2) The multi-faceted pyramidal structure is a 3- to 4-sided pyramid with acute-angled edges; A3) The stepped structure described above has an upper taper of 18°~20° and a lower taper of 24°~26°.

5. The brain-computer interface microarray electrode applicable to special silent communication according to claim 1, characterized in that, The conductivity of the PEDOT:Tos conductive coating is ≤900 S / cm.

6. The brain-computer interface microarray electrode applicable to special silent communication according to claim 1, characterized in that, The conductive coating has a cell survival rate of ≥95% and exhibits conductivity stability fluctuations of ≤10% under conditions of temperature -10℃ to 45℃ and humidity 30% to 80%.

7. The brain-computer interface microarray electrode applicable to special silent communication according to claim 1, characterized in that, The microneedle array structure has a biocompatible adhesive functional layer on its microneedle surface, and a conductive coating layer is provided on the biocompatible adhesive functional layer.

8. The brain-computer interface microarray electrode applicable to special silent communication according to claim 1, characterized in that, Adjacent microarray electrodes are connected by a flexible serpentine interconnect made of a polyimide / copper bilayer material.

9. The method for fabricating a brain-computer interface microarray electrode applicable to special silent communication according to any one of claims 1 to 8, characterized in that, The preparation method includes the following steps: 1) A conductive precursor solution was prepared by mixing ferric p-toluenesulfonate solution with 3,4-ethylenedioxythiophene. 2) The arrangement of the microneedle array is directly etched using two-photon lithography to obtain the microneedle array structure; 3) The conductive precursor solution is uniformly coated onto the surface of the microneedles using vertical spin coating technology, followed by heat treatment to initiate a polymerization reaction. After the reaction, the microneedles are cleaned and dried to form a PEDOT:Tos conductive coating layer on the surface of the microneedles, thus obtaining a microarray electrode.

10. The method for fabricating a brain-computer interface microarray electrode applicable to special silent communication according to claim 9, characterized in that, It also includes one or more of the following conditions: B1) In step 1), the volume ratio of the iron p-toluenesulfonate solution to 3,4-ethylenedioxythiophene is 18~22:1; B2) In step 1), the concentration of the ferric p-toluenesulfonate solution is 30~50 wt.%; In step 2) of B3), using Nano Scribe laser direct writing technology, the dimensional consistency error in mass production is ≤±1%; In step 3) of B4), the vertical spin coating technology includes attaching a microneedle array to the side of the spin coating plate, dropping a conductive precursor solution onto the upper surface of the microneedles and then rotating to homogenize the coating, then rotating the microneedle array structure 180° so that the lower surface faces upward, and repeating the operation. The amount of conductive precursor solution dropped in the two spin coatings is the same. In step 3) of B5, during the vertical spin coating process, the error in the amount of conductive precursor solution added is ≤ ±0.1 μL; In step 3) of B6, the temperature of the heat treatment is 60~100℃; the heat treatment time is 3~7 minutes. B7) In step 3), wash with isopropanol and deionized water in sequence; In step 3) of B8, the drying temperature is 60~100℃ and the drying time is 24 hours.

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