Optoelectronic integrated microneedle array brain-computer interface device and its preparation method

Abstract

The present invention provides an optoelectronically integrated microneedle array brain-computer interface device and its preparation method, comprising: a microneedle array portion, a light stimulation portion, and a photoelectric lead; the microneedle array portion comprises a microneedle array formed by a plurality of microneedles, each of which has a through-hole within; the light stimulation portion is located within the through-hole; and the photoelectric lead is used to connect the microneedle array portion and the light stimulation portion to external devices. The present invention combines the microneedle array for electrical stimulation and recording with the light stimulation portion to achieve optoelectronic integration. This enables simultaneous photoelectric stimulation and electrical recording at a single point, accurately records light stimulation signals, and effectively improves the quality of recorded neural signals.

Description

Technical Field

[0001] The present invention relates to the technical field of bioelectrodes, and in particular to a photoelectrically integrated integrated microneedle array brain-computer interface device and a preparation method thereof. Background Art

[0002] Neural electrodes are devices that connect biological tissue to external devices. They operate by converting bioelectrical signals, carried by ions, into electronic signals, carried by electrons, thereby enabling the reception and processing of neural signals. Therefore, neural electrodes have long been a core component in the fields of bioelectronics and brain science. Brain science has been a hot topic in modern scientific research, exploring the mechanisms by which the human brain generates, transmits, and processes information. Brain-computer interface (BCI) devices, one type of neural electrode, serve as a channel between the brain and external devices, enabling recording and stimulation of brain neurons and the analysis of cortical electrical signals. Compared to non-implantable EEG electrodes, implantable EEG electrodes offer superior signal quality and spatial and temporal resolution, enabling more effective and precise treatment for patients with epilepsy, Parkinson's disease, depression, and some sequelae of neurological trauma. To minimize damage to brain tissue during implantation, the size of the electrodes must be minimized. The emergence of MEMS (Micro-Electro-Mechanical System) technology has significantly advanced the development of EEG electrodes. Currently, implantable brain-computer interface devices mainly have three structures: flexible substrate, planar multi-point electrode (represented by Michigan electrode) and microneedle array (represented by Utah electrode).

[0003] The microneedle array brain-computer interface (BCI) device was first proposed by Normann et al. in 1989 in the paper "A silicon-based electrode array for intracortical stimulation: structural and electrical properties." This electrode integrates 100 1.5 mm long needle-tip electrodes on a 4 mm × 4 mm substrate, demonstrating its potential for chronic implantation. Consequently, needle-tip microarray BCIs have garnered increasing attention, and extensive research has been conducted on electrode surface modification materials, electrode biopassivation layers, implant tissue damage, and signal transmission. Microneedle arrays hold a significant position in BCI devices due to their numerous channels, excellent mutual insulation, high temporal and spatial resolution, ability to effectively penetrate deep into tissue for single-cell stimulation and recording, high signal quality, and long-term implantability. Microneedle arrays are fabricated using MEMS technology, primarily made of low-resistance silicon, which provides them with excellent mechanical properties and biocompatibility.

[0004] The original function of brain-computer interface devices was to stimulate and record from neurons electrically. The emergence of optogenetics has greatly enriched the capabilities of EEG electrodes. Optogenetics uses light to trigger neural excitation or inhibition. It involves introducing light-sensitive proteins into neurons and leveraging the sensitivity of specific light-sensitive proteins to specific wavelengths of light to observe and study neural activity. The emergence of optogenetics has attracted considerable research interest and significantly promoted and enriched the development of EEG electrodes. In 2016, Boutte et al. published an article in Biomedical Microdevice titled "Maskless wafer-level microfabrication of optical penetrating neural arrays out of soda-lime glass: Utah Optrode Array," proposing and testing a soda-lime glass-based optical microneedle array electrode. This array, based on the Utah electrode, can only achieve large-area optical stimulation of all the needles and cannot provide precise, point-to-point stimulation.

[0005] Since both light stimulation and electrical stimulation have their unique advantages, effectively combining the two has become a hot topic in the field of brain electrodes. In terms of implantable or attached planar flexible brain-computer interfaces and silicon-based planar multi-point electrodes, there has been a lot of related work on optoelectronic integration, but in microneedle array brain-computer interface devices, there is currently no effective method to achieve optoelectronic integration. In a published invention patent application, Li Zhihong and others from Peking University proposed a microneedle electrode array device, which controls electrical stimulation or light stimulation by inserting the optode and electrode a second time through the processing of a template. However, the processing process of this type of microneedle array brain-computer interface device is cumbersome and difficult to manufacture, and the metal microneedles cannot be processed and formed in one go, so it is not an effective integration method. In summary, MEMS processing has not yet been achieved in the existing microneedle array brain-computer interface, and there is no optoelectronic integrated brain-computer interface device that performs photoelectric stimulation and electrical recording at the same point. Summary of the Invention

[0006] In response to the defects in the existing technology, the purpose of the present invention is to provide an optoelectronic integrated integrated microneedle array brain-computer interface device and its preparation method, which combines the microneedle array for electrical stimulation and recording with the light stimulation part, can realize photoelectric stimulation and electrical recording of a single point, can accurately record the light stimulation signal, and effectively improve the quality of recorded neural signals.

[0007] According to one aspect of the present invention, there is provided an optoelectronic integrated microneedle array brain-computer interface device, comprising: a microneedle array portion, a light stimulation portion, and optoelectronic leads;

[0008] The microneedle array portion includes a microneedle array formed by a plurality of microneedles, each microneedle having a through hole inside; the light stimulation portion is located in the through hole; and the photoelectric lead is used to connect the microneedle array portion and the light stimulation portion with external equipment.

[0009] Furthermore, the microneedle array portion further includes an insulating substrate, which is disposed below the microneedle array and through which the microneedles are connected to each other; the insulating substrate is a rigid substrate or a flexible substrate.

[0010] Furthermore, the microneedle includes a needle tip, a needle body and a needle base from top to bottom. A conductive layer is formed on the surface of the microneedle, and a biological passivation layer is formed on the outside of the conductive layer. The biological passivation layer covers the part except the needle tip, and the tip part of the needle tip exposes the conductive layer; a metal pad is provided on the lower surface of the needle base, and the metal pad is connected to the photoelectric lead.

[0011] Furthermore, the material of the microneedle is conductive metal, conductive metal oxide, conductive polymer or doped semiconductor material.

[0012] Furthermore, the light stimulation part is an optical fiber, which includes an optical fiber core, an optical fiber corroded part, an optical fiber uncorroded part and an optical fiber light-emitting end face. The optical fiber corroded part and the optical fiber uncorroded part are arranged in sequence to form an optical fiber body. The optical fiber core is arranged inside the optical fiber, and the optical fiber light-emitting end face is located at the end of the optical fiber corroded part. The optical fiber corroded part is inserted into the through hole, and the optical fiber light-emitting end face is exposed from the top of the through hole.

[0013] Furthermore, the depth of the light stimulation portion inserted into the through hole is adjustable, and the diameter of the light stimulation portion is determined according to the diameter of the through hole.

[0014] Furthermore, the light emitting end surface of the light stimulation part at the top end of the through hole is a plane or an inclined surface.

[0015] Furthermore, the photoelectric lead includes an electrical lead and an optical lead. The electrical lead is a metal lead connecting an external device and the needle bottom; the optical lead is the part of the light stimulation part that is not inserted into the microneedle, and the optical lead is connected to the external device.

[0016] According to another aspect of the present invention, a method for preparing the above-mentioned optoelectronic integrated integrated microneedle array brain-computer interface device is provided, comprising:

[0017] Providing a semiconductor material substrate, and forming a through hole inside the microneedle on the semiconductor material substrate by etching;

[0018] forming an insulating base between the microneedles between the through holes;

[0019] removing the semiconductor material substrate below the insulating base to form a plurality of prisms;

[0020] corroding the prisms to form needle tips at the tops of the prisms, thereby forming a microneedle array;

[0021] forming a metal pad below the microneedle, forming a conductive layer and a biopassivation layer on the surface of the microneedle in sequence, and then etching away the biopassivation layer on the needle tip to expose the conductive layer;

[0022] The light stimulation part is inserted into the through hole and fixed.

[0023] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0024] 1. The present invention combines the microneedle array for electrical stimulation and recording with the light stimulation part to achieve optoelectronic integration, which can realize simultaneous photoelectric stimulation and electrical recording at a single point, accurately record the light stimulation signal, and effectively improve the quality of recorded neural signals.

[0025] 2. The present invention can effectively increase the integration of the device and reduce the size of the device by etching a through hole inside the microneedle to place the light stimulation part.

[0026] 3. The present invention can flexibly adjust the length, number and size of the microneedles according to the different cerebral cortical areas or nerve types of the subjects; the distance between the light-emitting point of the internal light stimulation part and the tip of the microneedle can be flexibly adjusted, which can detect the influence of the light source distance on the neuronal signal and reduce the influence of the photoelectric effect; the light-emitting surface of the internal light stimulation part can be adjusted in angle, which can also reduce the influence of light stimulation on electrical recordings; the insulating substrate can be made of rigid or flexible materials, which can adapt to the implantation requirements of different areas such as flat areas and grooves of the cerebral cortical tissue. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0028] Figure 1 Schematic diagram of the structure of an optoelectronically integrated microneedle array brain-computer interface device according to an embodiment of the present invention;

[0029] Figure 2 Schematic diagram of the structure of an optical fiber in an embodiment of the present invention;

[0030] Figure 3 is a schematic cross-sectional view of an optical fiber according to an embodiment of the present invention;

[0031] Figure 4 Schematic diagram of a process for preparing a device according to an embodiment of the present invention;

[0032] Figure 5 A schematic structural diagram of a device in another embodiment of the present invention;

[0033] Figure 6 Schematic diagram of the position of optical fibers in an embodiment of the present invention;

[0034] Figure 7 is a schematic cross-sectional view of an optical fiber according to an embodiment of the present invention;

[0035] Figure 8 Schematic diagram of the structure of the light-emitting end face of an optical fiber in an embodiment of the present invention;

[0036] Figure 9 Schematic diagram of the cross section of the light-emitting end face of the optical fiber in an embodiment of the present invention.

[0037] In the figure: 1 is the microneedle array part, 11 is the microneedle, 12 is the insulating base, 111 is the needle tip, 112 is the needle body, 113 is the needle bottom, 114 is the through hole, 2 is the light stimulation part, 21 is the optical fiber light output end face, 22 is the optical fiber corrosion part, 23 is the optical fiber uncorroded part, 24 is the optical fiber core, 3 is the photoelectric lead, 31 is the electrical lead, and 32 is the optical lead. DETAILED DESCRIPTION

[0038] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several variations and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0039] In the description of the embodiments of the present invention, it should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings 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 interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. The orientation and positional relationships indicated by the terms "upper", "lower", "top", "bottom", etc. are based on the orientation and positional relationships shown in the drawings, and are only used to facilitate the description of the present invention and its implementation methods, and do not indicate that the parts involved must have the specific orientation and position combination, and therefore cannot be understood as limiting the present invention.

[0040] The embodiment of the present invention provides an optoelectronic integrated microneedle array brain-computer interface device, referring to Figure 1 The device includes: a microneedle array part 1, a light stimulation part 2 and a photoelectric lead 3; the microneedle array part 1 includes a microneedle array formed by a plurality of microneedles 11, and the interior of the microneedle 11 has a through hole 114; the light stimulation part 2 is located in the through hole 114; the photoelectric lead 3 is used to connect the microneedle array part 1 and the light stimulation part 2 with external equipment.

[0041] The present invention combines a microneedle array 1 for electrical stimulation and recording with a photostimulation component 2, achieving optoelectronic integration. This minimizes the distance between photostimulation and electrical stimulation and recording, enabling simultaneous photoelectric stimulation and electrical recording at a single point, accurately recording the photostimulation signal, and effectively improving the quality of recorded neural signals. By etching through-holes 114 within the microneedles 11 to accommodate the photostimulation component 2, the device's integration level is increased and its size is reduced.

[0042] In some preferred embodiments, the microneedle array portion 1 further includes an insulating substrate 12, which is disposed below the microneedle array, and the microneedles 11 are connected to each other through the insulating substrate 12; the insulating substrate 12 is a rigid substrate or a flexible substrate, which can adapt to the implantation requirements of different areas such as flat areas and grooves of the cerebral cortex tissue.

[0043] The rigid material and the flexible material serve to insulate the microneedles. In some preferred embodiments, the rigid material has better bonding strength with the microneedles. The material can be any one of glass, plastic and polymethyl methacrylate. Considering the processing technology and reliability, glass is more preferred. Glass has better physical compatibility with silicon after melting at high temperature. The flexible material can enable the microneedle array to meet the effective fitting requirements in the groove area of the brain. The material can be any one of polyparaxylene, polyimide and polydimethylsiloxane, all of which have good biocompatibility. Considering the good bonding strength and adjustability of the elastic modulus, polydimethylsiloxane is more preferred. Its hardness is easy to change and its viscosity is appropriate.

[0044] Each microneedle 11 of the microneedle array has a through-hole 114 for accommodating the internal light stimulation portion 2. In some preferred embodiments, the microneedles 11 include, from top to bottom, a needle tip 111, a needle body 112, and a needle base 113. A conductive layer is formed on the surface of the microneedle 11, and a biopassivation layer is formed on the outside of the conductive layer. The biopassivation layer covers the entire surface except the needle tip 111, with the tip of the needle tip 111 exposed from the conductive layer. The preparation method specifically comprises first covering the microneedle surface with a conductive layer, then depositing a biopassivation layer on the entire device, and then etching away the biopassivation layer on the needle tip to expose the conductive layer. A metal pad is provided on the lower surface of the needle base 113, which is connected to the photoelectric lead 3.

[0045] In some preferred embodiments, the conductive layer on the surface of the microneedle 11 is formed by depositing a layer of conductive material. The deposition method can be any one of evaporation, sputtering and electroplating. The conductive material must have good conductivity and biocompatibility. It can be any one of metals, conductive polymers and conductive metal oxides. In view of the batch process, conductive metal oxides such as iridium oxide are more preferred. The sputtering process is relatively convenient, the impedance is low and it is suitable for surface modification of brain-computer interface devices; the entire device except the needle tip 111 of the microneedle 11 is coated with a biopassivation layer. The biopassivation layer requires long-term stability and biocompatibility in the body. The material is a polymer material such as any one of polyimide film, polydimethylsiloxane film, amorphous silicon carbide and polyparaxylene film. Considering the chemical stability, polyparaxylene film is more preferred, which has good chemical corrosion resistance, biocompatibility and mature deposition process.

[0046] The back of the needle bottom 113 is sputtered with metal as a metal pad. The metal pad establishes a stable electrical path between the electrode and the external device. In order to make it have good conductivity and biocompatibility and facilitate wire bonding, the material of the metal pad is mainly conductive metal, preferably chromium / gold.

[0047] In some preferred embodiments, the material of the microneedle 11 is a conductive metal, a conductive metal oxide, a conductive polymer or a doped semiconductor material. In order to achieve batch miniaturization manufacturing, a low-resistance silicon wafer that is more compatible with MEMS technology is preferred.

[0048] In this embodiment, the length, diameter, internal through-hole size, number of microneedles and thickness of the insulating substrate 12 of the microneedles 11 are determined according to specific circumstances and are not specifically limited in this embodiment of the present invention.

[0049] It will be understood by those skilled in the art that when the number of the microneedles 11 is 1, since there is no need to connect the microneedles 11 , there is no need to provide the insulating substrate 12 .

[0050] The light stimulation part 2 includes an optical waveguide. The light stimulation part 2 can be any optical medium material or device. In some preferred embodiments, for example, Figure 2-3 The light stimulation part 2 is an optical fiber. The diameter of the optical fiber itself is fixed. In order to increase the integration, the front end of the optical fiber can be corroded and then manufactured. The optical fiber includes an optical fiber core 24, an optical fiber corroded part 22, an optical fiber uncorroded part 23 and an optical fiber light-emitting end face 21. The optical fiber corroded part 22 and the optical fiber uncorroded part 23 are arranged in sequence to form an optical fiber body. The optical fiber core 24 is arranged inside the optical fiber. The optical fiber light-emitting end face 21 is located at the end of the optical fiber corroded part 22. The optical fiber corroded part 22 is inserted into the through hole 114, and the optical fiber light-emitting end face 21 is exposed from the top of the through hole 114. It can be understood by those skilled in the art that when the diameter of the through hole 114 inside the microneedle 11 is larger than the diameter of the optical fiber itself, the optical fiber can be directly inserted without corrosion. The optical fiber corroded part 22 is the optical fiber itself.

[0051] In some preferred embodiments, the depth of the light stimulation part 2 inserted into the through hole 114 is adjustable, and the diameter of the light stimulation part 2 is determined according to the diameter of the through hole 114. The diameter of the internal optical fiber can be changed by wet etching.

[0052] The light stimulation part 2 is inserted into the part of the microneedle 11. The length of the internal light stimulation part 2 can be changed according to actual needs. The length can be less than the length of the microneedle 11 or exceed the needle tip 111. The diameter of the internal light stimulation part 2 can be adjusted according to the diameter of the through hole 114.

[0053] In some preferred embodiments, the light-emitting end surface of the light stimulation portion 2 at the top of the through-hole 114, near the needle tip 111, is flat or inclined to change the direction of light propagation. If the light-emitting end surface is inclined, it can be produced by etching or grinding. The internal optical fiber and microneedle 11 can be fixed by gluing, using UV-curable glue or epoxy resin.

[0054] In some preferred embodiments, the photoelectric lead 3 includes an electrical lead 31 and an optical lead 32. The electrical lead 31 is a metal lead connecting an external device with the needle bottom 113. Specifically, the electrical lead 31 is connected to the metal pad by a wire bonding method; the optical lead 32 is the part of the light stimulation part 2 that is not inserted into the microneedle 11, and the optical lead 32 is connected to the external device.

[0055] The embodiments of the present invention can flexibly adjust the length, number and size of the microneedles according to the different cerebral cortical areas or nerve types of the subjects; the distance between the light-emitting point of the internal light stimulation part 2 and the tip of the microneedle can be flexibly adjusted, which can detect the influence of the light source distance on the neuronal signal and reduce the influence of the photoelectric effect; the light-emitting surface of the internal light stimulation part 2 can be adjusted in angle, which can also reduce the influence of light stimulation on electrical recording.

[0056] In order to improve the adaptability of brain-computer interface devices and meet the testing requirements of brain grooves or different depths of implanted nerves, the lengths of the microneedles 11 of the microneedle array part 1 can be different. In some other preferred embodiments, the lengths of the microneedles 11 are constructed to increase from short to long or increase proportionally from one end of the microneedle array part 1. For example, the lengths of the microneedles 11 can increase from short to long or increase proportionally from one end in the length direction or one end in the width direction of the microneedle array part 1. Figure 5 As shown, the length of the microneedles 11 increases from short to long, with an increase gradient of 0.1 mm. It should be noted that the length change gradient of the microneedles 11 is not limited to this preferred example, and can be increased proportionally or combined in any manner under the conditions allowed by the processing technology.

[0057] Similarly, in order to meet the testing requirements of different applications or depths in animal or clinical experiments, in other preferred embodiments, within the area of the microneedle array portion 1, the length of the microneedle 11 is constructed to be long in the middle and short around the four sides or short in the middle and long around the four sides.

[0058] In other embodiments, the depth of the optical fiber corrosion portion 22 inserted into the through hole 114 can be changed. Figure 6-7 The figure is a schematic diagram of the position and cross section of another preferred embodiment of the present invention. In the figure, the length of the optical fiber corrosion portion 22 is less than the length of the through hole 114. In experimental tests, the length of the optical fiber corrosion portion 22 can also be equal to or greater than the depth of the through hole 114. If Figure 1 and Figure 5 In the case of the microneedle array shown, the length relationship between the optical fiber corrosion portion 22 and the through hole 114 of each microneedle 11 can be arbitrarily changed according to the test environment. For example, when placed in different brain regions, the length relationship can be changed according to the specific groove shape.

[0059] Figure 8-9 This is a structural diagram of the optical fiber light-emitting end face of another preferred embodiment of the present invention. In addition to the flat light-emitting end face, it can also be ground to a certain angle by a fiber optic angle grinder. Figure 8-9 As shown, the optical fiber light-emitting end face 21 is an inclined plane at 60 degrees to the optical fiber axis. The angled optical fiber light-emitting end face 21 can change the direction of light emission, thereby altering the effect of light stimulation on the electrode recording signal. The angle of the optical fiber light-emitting end face 21 can be arbitrarily changed. It should be noted that within the same needle-tip microelectrode array, the angle of the optical fiber light-emitting end face 21 is not restricted; different microneedles 11 can correspond to optical fiber light-emitting end faces 21 at different angles.

[0060] The embodiment of the present invention also provides a method for preparing the above-mentioned optoelectronic integrated integrated microneedle array brain-computer interface device, the method comprising:

[0061] Providing a semiconductor material substrate, and forming a through hole 114 inside the microneedle on the semiconductor material substrate by etching;

[0062] An insulating base 12 is formed between each microneedle between the through holes 114;

[0063] Removing the semiconductor material substrate below the insulating base 12 to form a plurality of prisms;

[0064] Eroding the prism to form a needle tip 111 at the top of the prism, thereby forming a microneedle array;

[0065] forming a metal pad below the microneedle, forming a conductive layer and a biopassivation layer on the surface of the microneedle in sequence, and then etching away the biopassivation layer on the needle tip 111 to expose the conductive layer;

[0066] The light stimulation part 2 is inserted into the through hole 114 and fixed.

[0067] Furthermore, after the light stimulation part 2 is inserted into the through hole 114 and fixed, and the light stimulation part 2 is exposed from the top of the through hole 114, it also includes: making a photoelectric lead 3, which is used to connect the microneedle array part 1 and the light stimulation part 2 with external equipment.

[0068] This embodiment of the present invention integrates a light stimulation component within the microneedle, allowing light stimulation and electrical recording to occur at the same point, improving measurement accuracy. The fabrication method for the device in this embodiment of the present invention is further described using a microneedle 11 with a length of 1.5 mm, a number of 100 needles, a needle body 112 with a diameter of 0.1 mm, an internal through-hole 114 with a diameter of 50 μm, and an insulating substrate 12 with a thickness of 0.12 mm as an example.

[0069] like Figure 4 As shown, first, a silicon wafer with a thickness of 2000um, a resistance of 0.01-0.05Ω-cm, and a crystal orientation of (100) was selected for processing. The silicon wafer was ultrasonically cleaned with acetone, isopropyl alcohol, and deionized water for ten minutes each to remove organic particles, dust, etc. on the surface of the wafer.

[0070] Step a: forming a through hole 114 inside the microneedle 11; etching through the silicon wafer using a deep silicon etching method, with an etching diameter of about 50 μm;

[0071] Step b: Deep silicon etching is used to create crisscrossing grooves approximately 0.12mm deep and 0.2mm wide. Glass powder is then dissolved in methanol to form a slurry, which is then filled into the grooves and solidified. The silicon wafer is then placed in a high-temperature heating furnace, which is first evacuated and then heated to 1100°C for 90 minutes. Finally, the glass powder is removed from the wafer's surface by grinding and polishing, ensuring a smooth and clean surface.

[0072] Step c: Use a deep silicon etch / dicing machine to etch / cut the silicon wafer below the glass powder groove to a width consistent with the width of the glass powder groove. At this time, the silicon wafer forms quadrangular prisms with internal through holes.

[0073] Step d: etching the silicon column; etching the silicon prism with a mixed solution of hydrofluoric acid and nitric acid to form a Figure 4 The needle tip shape is shown.

[0074] Step e: sputtering the electrode material on the surface of the needle tip 111, the metal layer on the lower surface of the needle base 113, and depositing a biopassivation layer; first, 30 nanometers of chromium and 300 nanometers of gold are sputtered in sequence on the lower surface of the needle base 113 as metal pads between the electrical lead 31 and the microneedle 11; then, using aluminum foil as a mask, a layer of iridium oxide film with a thickness of 200 nm is sputtered on the surface of the needle tip 111; then, a biopassivation layer of polyparaxylene film is deposited on the surface of the microneedle 11; finally, the biopassivation layer at the tip of the needle tip 111 is removed by dry etching to expose the electrode material.

[0075] Step f: etching the optical fiber; etching the tip of the optical fiber with a hydrofluoric acid solution, wherein the length of the etching portion is determined by the actual length of the internal through hole 114, and the etching time is determined by the diameter of the internal through hole 114.

[0076] Step g: Insert the corroded optical fiber into the internal through hole 114 and fix it with UV curing glue to finally form an optoelectronic integrated integrated microneedle array brain-computer interface device. The direction of the arrow in the figure indicates the direction of light propagation.

[0077] The device in the above-mentioned embodiment of the present invention combines the microneedle array for electrical stimulation and recording with the light stimulation part to realize optoelectronic integration, which can realize simultaneous photoelectric stimulation and electrical recording at a single point, accurately record the light stimulation signal, and effectively improve the quality of recorded neural signals; by etching through holes inside the microneedles to place the light stimulation part, the integration of the device can be effectively increased and the size of the device can be reduced.

[0078] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various modifications or variations within the scope of the claims without affecting the essence of the present invention. The above preferred features may be used in any combination as long as they do not conflict with each other.

Claims

1. An optoelectronic integrated microneedle array brain-computer interface device, characterized in that: include: Microneedle array part, light stimulation part and photoelectric leads; The microneedle array portion includes a microneedle array formed by a plurality of microneedles, each of the microneedles having a through hole therein; The light stimulation part is located in the through hole; the photoelectric lead is used to connect the microneedle array part and the light stimulation part with external equipment; The light stimulation part is an optical fiber, which includes an optical fiber core, an optical fiber corroded part, an optical fiber uncorroded part and an optical fiber light-emitting end face. The optical fiber corroded part and the optical fiber uncorroded part are arranged in sequence to form an optical fiber body. The optical fiber core is arranged inside the optical fiber, and the optical fiber light-emitting end face is located at the end of the optical fiber corroded part. The optical fiber corroded part is inserted into the through hole, and the optical fiber light-emitting end face is exposed from the top of the through hole.

2. The optoelectronic integrated microneedle array brain-computer interface device according to claim 1, characterized in that: The microneedle array portion further includes an insulating substrate, which is disposed below the microneedle array. The microneedles are connected to each other via the insulating substrate. The insulating substrate is a rigid substrate or a flexible substrate.

3. The optoelectronic integrated microneedle array brain-computer interface device according to claim 1, characterized in that: The microneedle includes a needle tip, a needle body and a needle base from top to bottom. A conductive layer is formed on the surface of the microneedle, and a biopassivation layer is formed on the outside of the conductive layer. The biopassivation layer covers the part except the needle tip, and the tip of the needle tip exposes the conductive layer; a metal pad is provided on the lower surface of the needle base, and the metal pad is connected to the photoelectric lead.

4. The optoelectronic integrated microneedle array brain-computer interface device according to claim 1, characterized in that: The material of the microneedle is conductive metal, conductive metal oxide, conductive polymer or doped semiconductor material.

5. The optoelectronic integrated microneedle array brain-computer interface device according to claim 1, characterized in that: The depth of the light stimulation part inserted into the through hole is adjustable, and the diameter of the light stimulation part is determined according to the diameter of the through hole.

6. The optoelectronic integrated microneedle array brain-computer interface device according to claim 1, characterized in that: The light emitting end surface of the light stimulation part at the top end of the through hole is a plane or an inclined surface.

7. The optoelectronic integrated microneedle array brain-computer interface device according to claim 3, characterized in that: The photoelectric lead includes an electrical lead and an optical lead. The electrical lead is a metal lead connecting an external device and the needle bottom; the optical lead is the portion of the light stimulation part that is not inserted into the microneedle, and the optical lead is connected to an external device.

8. A method for preparing the optoelectronic integrated microneedle array brain-computer interface device according to any one of claims 1 to 7, characterized in that: include: Providing a semiconductor material substrate, and forming a through hole inside the microneedle on the semiconductor material substrate by etching; forming an insulating base between the microneedles between the through holes; removing the semiconductor material substrate below the insulating base to form a plurality of prisms; corroding the prisms to form needle tips at the tops of the prisms, thereby forming a microneedle array; forming a metal pad below the microneedle, forming a conductive layer and a biopassivation layer on the surface of the microneedle in sequence, and then etching away the biopassivation layer on the needle tip to expose the conductive layer; The light stimulation part is inserted into the through hole and fixed.

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