A large-scale magnetically controlled flexible brain-computer interface and a preparation method thereof

Abstract

The application discloses a large-scale magnetic control flexible brain-computer interface and a preparation method thereof, wherein the magnetic control flexible brain-computer interface comprises a printed circuit board, a flexible magnetic control electrode, a reference electrode and a polyvinylpyrrolidone rigid shell; the printed circuit board is connected with the flexible magnetic control electrode and the reference electrode respectively, and the polyvinylpyrrolidone rigid shell is wrapped outside the flexible magnetic control electrode; the flexible magnetic control electrode comprises an electrode inner core, an electrode magnetic head and an electrode shell, the electrode magnetic head is arranged at one end of the electrode inner core, and the electrode shell is wrapped outside the electrode inner core. The flexible magnetic control electrode and the polyvinylpyrrolidone rigid shell are adopted in the embodiment, electrode control can be realized, the signal acquisition range is enlarged, the damage to nerve tissues is reduced, and the application can be widely applied to the technical field of brain-computer interface.

Description

Technical Field

[0001] This invention relates to the field of brain-computer interface technology, and in particular to a large-scale magnetically controlled flexible brain-computer interface and its fabrication method. Background Technology

[0002] Currently, clinical monitoring of electroencephalograms (EEGs) is primarily achieved through brain-computer interfaces (BCIs) to monitor electrical signals in the cerebral cortex and generate EEGs. However, due to the poor spatial resolution of cortical EEGs and advancements in medicine and neurology, the demand for EEG signal acquisition has shifted towards deep brain EEG and the exploration of neural signal pathways and potential brain circuits across multiple brain regions. This makes research into implantable deep-brain BCIs an urgent priority. A BCI establishes a continuous, direct, and scalable pathway between the brain and an external device using electrophysiological detection. On one hand, it allows the acquisition of electrical signals that the external device can recognize and process for effective control; on the other hand, it can input feedback from the external device back to the brain, forming a closed loop for information exchange. However, traditional BCIs use rigid implantable electrodes, which are highly destructive to tissues when multiple electrodes are implanted, difficult to reposition after implantation, and have limited range of neuronal electrical signal acquisition. Summary of the Invention

[0003] In view of this, embodiments of the present invention provide a simple and practical large-scale magnetically controlled flexible brain-computer interface and its fabrication method.

[0004] On one hand, the present invention provides a large-scale magnetically controlled flexible brain-computer interface, including a printed circuit board, a flexible magnetically controlled electrode, a reference electrode, and a polyvinylpyrrolidone rigid shell; the printed circuit board is connected to the flexible magnetically controlled electrode and the reference electrode respectively, and the polyvinylpyrrolidone rigid shell is wrapped around the flexible magnetically controlled electrode; the flexible magnetically controlled electrode includes an electrode core, an electrode head, and an electrode shell, the electrode head is disposed at one end of the electrode core, and the electrode shell is wrapped around the electrode core.

[0005] Optionally, the magnetically controlled flexible brain-computer interface further includes a connector, which is soldered to the interface of the printed circuit board. The connector is used to connect the printed circuit board and the multi-channel signal acquisition system.

[0006] Optionally, the printed circuit board includes a first electrical contact and a second electrical contact, wherein the first electrical contact is used to connect the magnetized flexible electrode and the second electrical contact is used to connect the reference electrode.

[0007] Optionally, the electrode core is made of flexible metallic or non-metallic material, including at least one of platinum-iridium alloy wire and conductive polymer fiber.

[0008] Optionally, the electrode head is a magnetic microparticle material, including at least one of iron oxide spherical nanoparticles, neodymium iron boron microparticles, and iron cobalt nickel magnetic microparticles.

[0009] Optionally, the electrode housing comprises at least one of poly(L-lactic acid) and poly(glycolic acid) lactide.

[0010] On the other hand, embodiments of the present invention also disclose a method for fabricating a large-scale magnetically controlled flexible brain-computer interface, comprising:

[0011] Tubular molds are obtained by casting polymer fiber molds or metal wire molds using polydimethylsiloxane.

[0012] The electrode wire is passed through the tubular mold, and a mixture of epoxy resin and magnetic particles is injected into the tubular mold. After the mixture solidifies, an electrode core with an electrode head is obtained.

[0013] Poly-L-lactic acid is coated onto the electrode core with the electrode head to obtain a magnetically controlled flexible electrode.

[0014] The magnetically controlled flexible electrode and the reference electrode are connected to a printed circuit board, and the magnetically controlled flexible electrode is coated with a polyvinylpyrrolidone solution. After the polyvinylpyrrolidone solution dries, a magnetically controlled flexible brain-computer interface is obtained.

[0015] Optionally, the step of passing the electrode wire through the tubular mold and injecting a mixture of epoxy resin and magnetic particles into the tubular mold, allowing the mixture to solidify to obtain an electrode core with an electrode head, includes:

[0016] The electrode wire is passed through the tubular mold to obtain the first mold;

[0017] A mixture containing epoxy resin and magnetic particles is injected into the first mold to obtain a second mold;

[0018] The second mold is magnetized in an axial parallel magnetic field. After the mixture solidifies, an electrode core with an electrode head is obtained.

[0019] Optionally, the step of coating the electrode core with the electrode head with poly-L-lactic acid to obtain a magnetically controlled flexible electrode includes:

[0020] Poly-L-lactic acid was melted using a thermoplastic method to obtain a poly-L-lactic acid melt.

[0021] The electrode core with the electrode head is pulled out from the poly-L-lactic acid melt, so that the poly-L-lactic acid coats the electrode core with the electrode head, thus obtaining a magnetically controlled flexible electrode.

[0022] Optionally, the polyvinylpyrrolidone solution is prepared using anhydrous ethanol as a solvent and 15% polyvinylpyrrolidone by mass / volume as a solute.

[0023] Compared with existing technologies, the present invention, employing the above technical solutions, has the following technical effects: An embodiment of the present invention provides a large-scale magnetically controlled flexible brain-computer interface, comprising a printed circuit board, flexible magnetically controlled electrodes, a reference electrode, and a rigid polyvinylpyrrolidone shell; the embodiment of the present invention uses flexible magnetically controlled electrodes, enabling precise control of the electrode position through a controllable magnetic field generator via the electrode magnetic head, and allowing for the acquisition of neuronal electrophysiological signals over a large area of ​​the brain; furthermore, the embodiment of the present invention, through the rigid polyvinylpyrrolidone shell, can degrade non-toxically after implantation of the magnetically controlled flexible electrodes, reducing damage to brain tissue after electrode implantation. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of a magnetically controlled flexible brain-computer interface structure according to an embodiment of the present invention;

[0026] Figure 2 This is a flowchart of a method for fabricating a magnetically controlled flexible brain-computer interface according to an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the present invention will be described below in conjunction with the explanation of terms.

[0028] Brain-computer interfaces (BCIs) refer to the direct connection established between the brain of a person or animal and an external device, enabling information exchange between the brain and the device. Sometimes called a "brain port" or "brain-computer fusion sensing," it is a direct connection pathway established between the brain (or a culture of brain cells) of a person or animal and an external device. In the case of a unidirectional BCI, the computer either receives commands from the brain or sends signals to the brain (e.g., video reconstruction), but cannot send and receive signals simultaneously. Bidirectional BCIs allow for bidirectional information exchange between the brain and external devices. BCIs include non-invasive, invasive, and semi-invasive types. Non-invasive BCIs primarily achieve this by monitoring electrical signals in the cerebral cortex to generate an electroencephalogram (EEG), but the spatial resolution of cortical EEG is poor. Semi-invasive BCIs mainly rely on electrocorticography (ECoG) for information analysis, but the signal strength and resolution obtained are weaker than invasive BCIs. Traditional invasive BCIs primarily use metal electrodes as the implanted interface, offering a high signal-to-noise ratio and a wide frequency range, making them less susceptible to motion artifacts and noise. However, to maintain a certain rigidity for successful implantation, these implants are generally large in size, making it difficult to achieve large-scale, multi-channel detection. Furthermore, the presence of free movement in the experimental subject can cause a mechanical mismatch between the rigid implant and the elastic modulus of brain tissue, leading to a series of inflammatory and rejection reactions, resulting in limited signal recording and restricting electrode applications. Despite significant progress in highly composite, flexible, and biocompatible neural electrodes over the past few decades, developing a seamless interface remains a major challenge. Although multi-handled probes have been developed to probe subcortical tissue activity, tissue damage caused by multiple implantation sites greatly limits their spatial coverage and neuroscience applications. The magnetically controlled flexible brain-computer interface proposed in this invention can map three-dimensional brain activity across distant regions deep within the brain while minimizing tissue damage.

[0029] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0030] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0031] In the description of this invention, "several" means one or more, "more than" means two or more, and "greater than," "less than," "exceeding," etc., are understood to exclude the stated number. The use of terms such as "first," "second," "third," etc., is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly specifying the number of indicated technical features or their sequential relationship.

[0032] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0033] Reference Figure 1 This invention provides a large-scale magnetically controlled flexible brain-computer interface, including a printed circuit board 1, a flexible magnetically controlled electrode 2, a reference electrode 3, and a polyvinylpyrrolidone rigid shell 4; the printed circuit board 1 is connected to the flexible magnetically controlled electrode 2 and the reference electrode 3 respectively, and the polyvinylpyrrolidone rigid shell 4 is wrapped around the flexible magnetically controlled electrode 2; the flexible magnetically controlled electrode 2 includes an electrode core 201, an electrode magnetic head 202, and an electrode shell 203, the electrode magnetic head 202 is disposed at one end of the electrode core 201, and the electrode shell 203 is wrapped around the electrode core 201.

[0034] In this embodiment of the invention, a flexible magnetically controlled electrode is employed, consisting of an electrode core, an electrode magnetic head, and a motor housing. This allows for precise control of the electrode via a controllable magnetic field generator. In this embodiment, the electrode magnetic head is modified with a magnetic nano-coating to be controlled by a magnetic field, thereby expanding the range of neuronal electrophysiological signal acquisition. Furthermore, this embodiment of the invention covers the flexible magnetically controlled electrode with a rigid polyvinylpyrrolidone (PVP) shell. The PVP rigid shell ensures the rigidity required during implantation and rapidly and non-toxically degrades after implantation, quickly restoring the electrode's flexibility to match the elastic modulus of brain tissue. This reduces damage to brain tissue after electrode implantation and facilitates magnetic field control.

[0035] As a further preferred embodiment, the magnetically controlled flexible brain-computer interface also includes a connector, which is soldered to the interface of the printed circuit board. The connector is used to connect the printed circuit board and the multi-channel signal acquisition system.

[0036] Reference Figure 1This embodiment of the magnetically controlled flexible brain-computer interface also includes a connector 5, which is soldered to an interface on the printed circuit board 1. The connector connects the printed circuit board and a multi-channel signal acquisition system, which acquires neural signals via magnetically controlled flexible electrodes. In this embodiment, a connector with a spacing of 1.27 mm is used. It is understood that this embodiment can select appropriate connectors to form the magnetically controlled flexible brain-computer interface according to the actual application scenario.

[0037] As a further preferred embodiment, the printed circuit board includes a first electrical contact and a second electrical contact, the first electrical contact being used to connect to the magnetized flexible electrode, and the second electrical contact being used to connect to the reference electrode.

[0038] In this embodiment of the invention, the printed circuit board is designed with nine electrical contacts. Eight of these contacts are first contacts, connected to the magnetically controlled flexible electrode prepared in this embodiment, serving as working electrodes for collecting local field potentials of neurons after implantation into brain tissue. The remaining contact is a second contact, connected to the magnetically controlled flexible electrode, serving as a reference electrode for electrophysiological signal acquisition. It is understood that the number of electrical contacts in this embodiment of the invention is not fixed and can be selected and determined according to actual needs.

[0039] As a further preferred embodiment, the electrode core is made of flexible metallic or non-metallic material, including at least one of platinum-iridium alloy wire and conductive polymer fiber.

[0040] As a further preferred embodiment, the electrode head is a magnetic microparticle material, including at least one of iron oxide spherical nanoparticles, neodymium iron boron microparticles, and iron cobalt nickel magnetic microparticles.

[0041] As a further preferred embodiment, the electrode housing comprises at least one of poly(L-lactic acid) and poly(glycolic acid) lactide.

[0042] Specifically, one embodiment of the present invention provides a large-scale magnetically controlled flexible brain-computer interface, comprising a header, a printed circuit board, flexible magnetically controlled electrodes, a reference electrode, and a rigid polyvinylpyrrolidone shell. The header uses a 1.27mm pitch header, and the printed circuit board is designed with nine electrical contacts, eight of which are first electrical contacts connected to the flexible magnetically controlled electrodes, and one is a second electrical contact connected to the reference electrode. The electrode core of the flexible magnetically controlled electrode is made of platinum-iridium alloy wire, the electrode head is made of iron oxide spherical nanoparticles, and the electrode shell is made of polylactic acid (PLA) prepared by thermoplastic method.

[0043] Reference Figure 2 This invention provides a method for fabricating a large-scale magnetically controlled flexible brain-computer interface, comprising:

[0044] S101. Use polydimethylsiloxane to cast polymer fiber molds or metal wire molds to obtain tubular molds;

[0045] S102. Pass the electrode wire through the tubular mold and inject a mixture of epoxy resin and magnetic particles into the tubular mold. After the mixture solidifies, an electrode core with an electrode head is obtained.

[0046] S103. Coating the electrode core with the electrode head with poly-L-lactic acid to obtain a magnetically controlled flexible electrode;

[0047] S104. Connect the magnetically controlled flexible electrode and the reference electrode to the printed circuit board respectively, and immerse the magnetically controlled flexible electrode in a polyvinylpyrrolidone solution. After the polyvinylpyrrolidone solution dries, a magnetically controlled flexible brain-computer interface is obtained.

[0048] In this embodiment of the invention, a tubular mold is first fabricated using high-toughness polymer fibers or metal wires as a mold and cast with polydimethylsiloxane (PDMS). Next, electrode wires are passed through the tubular mold, and a mixture pre-mixed with epoxy resin and magnetic particles is injected into the mold. After the epoxy resin solidifies, the tubular mold is slowly peeled off to obtain an electrode core with an electrode head. Then, poly(L-lactic acid) is used to coat the electrode core with the electrode head using a thermoplastic method, forming an electrode shell outside the core to prepare a magnetically controlled flexible electrode. Finally, the magnetically controlled flexible electrode and a reference electrode are connected to a printed circuit board, and the electrode is impregnated with a polyvinylpyrrolidone (PVP) solution. After the PPVD solution dries, a magnetically controlled flexible brain-computer interface is obtained. It is understood that this embodiment can also use a female connector soldered to the printed circuit board as an interface between the electrode and a multi-channel signal acquisition system.

[0049] Further, as a preferred embodiment, in step S102 above, the step of passing the electrode wire through the tubular mold and injecting a mixture of epoxy resin and magnetic particles into the tubular mold, and then allowing the mixture to solidify to obtain an electrode core with an electrode head, includes:

[0050] The electrode wire is passed through the tubular mold to obtain the first mold;

[0051] A mixture containing epoxy resin and magnetic particles is injected into the first mold to obtain a second mold;

[0052] The second mold is magnetized in an axial parallel magnetic field. After the mixture solidifies, an electrode core with an electrode head is obtained.

[0053] In this embodiment, a platinum-iridium alloy wire is used as the electrode wire, i.e., the electrode core. Specifically, this embodiment uses a high-toughness metal wire (tungsten wire, nickel-chromium wire) with a diameter of 100±1μm as a template. The template is cast using PDMS and cured at 70℃ for more than 4 hours. The metal wire is then extracted to obtain a PDMS cavity with an inner diameter of 100±1μm, thus preparing a tubular mold. It is conceivable that in this embodiment, the tubular template can be selectively cut to the same width for later use. Next, in this embodiment, the electrode wire is passed through the tubular mold to obtain the first mold. Then, in this embodiment, epoxy resin is pre-mixed, and 100nm diameter Fe3O4 spherical nanoparticles are mixed at 60%... V / V The mixture is mixed with epoxy resin in a specific ratio, and the mixture is injected into the first mold to prepare the second mold. Finally, in this embodiment, the second mold is magnetized in an axial parallel magnetic field using a pulsed magnetic field. After curing at room temperature, a platinum-iridium alloy wire with magnetic particles modified on its head is obtained, thus preparing the electrode core with an electrode head.

[0054] As a further preferred embodiment, in step S103 above, coating the electrode core with the electrode head with poly-L-lactic acid to obtain a magnetically controlled flexible electrode includes:

[0055] Poly-L-lactic acid was melted using a thermoplastic method to obtain a poly-L-lactic acid melt.

[0056] The electrode core with the electrode head is pulled out from the poly-L-lactic acid melt, so that the poly-L-lactic acid coats the electrode core with the electrode head, thus obtaining a magnetically controlled flexible electrode.

[0057] In this embodiment, polylactic acid (PLLA) is melted at 230°C using a thermoplastic method. The electrode wire is then uniformly pulled out of the molten PLLA, resulting in a uniform coating of the electrode wire with PLLA, thus preparing a magnetically controlled flexible electrode. This embodiment uses PLLA as the electrode shell, which provides some support for the electrode microfilaments and offers good biocompatibility after implantation into brain tissue.

[0058] As a further preferred embodiment, the polyvinylpyrrolidone solution is prepared using anhydrous ethanol as a solvent and 15% polyvinylpyrrolidone by mass / volume as a solute.

[0059] In this embodiment, a PVP shell is coated onto the electrode array using a dip-coating method. After vacuum drying, it facilitates the implantation of flexible electrodes. The coated PVP (polyvinylpyrrolidone) solution uses anhydrous ethanol as the solvent and 15% PVP by volume as the solute. After being placed in a vacuum dryer at room temperature for 5 minutes, the solvent evaporates, resulting in a rigid PVP shell with high rigidity. This rigid PVP shell ensures the rigidity required for electrode implantation. Due to the water solubility of the PVP shell, it can rapidly and non-toxically degrade after the flexible electrode is implanted, restoring the electrode flexibility to match the elastic modulus of brain tissue in a short time, reducing damage to brain tissue after electrode implantation, and facilitating magnetic field manipulation. In some embodiments, the effects of magnetically controlled flexible electrodes in a magnetically controlled flexible brain-computer interface coated with a rigid PVP shell were simulated and compared. The experiment showed that the PVP-coated electrodes had sufficient rigidity to penetrate tissue. Furthermore, in some embodiments, a variety of coating materials were compared from multiple functional dimensions, including polyethylene glycol, silk fibroin and agarose hydrogel materials. In the experiment, it was found that PVP material has advantages such as moderate material cost, fast solvent evaporation and molding, high hardness, small coating thickness can be used as a shell layer to wrap the inner core of the electrode, and fast release motor speed.

[0060] Specifically, in the first embodiment of the present invention, a magnetically controlled flexible brain-computer interface is prepared by a large-scale magnetically controlled flexible brain-computer interface preparation method. Only a small window (the wound surface is about a circle with a radius of about 1 mm) large enough to accommodate the brain-computer interface of this embodiment needs to be made in the skull. The brain-computer interface with a PVP shell is implanted into the brain. The PVP shell dissolves rapidly after the device is implanted, releasing the flexible microfilament electrodes inside the shell. Under the control of an external magnetic field, the microfilament electrodes move in a controlled manner in the brain tissue, realizing the positioning of multiple microfilament electrodes in different brain regions after penetrating the brain tissue. Thus, local neuronal field potentials (LFP) in different regions of the deep brain can be collected at the same time. This can be used as a research tool to explore deep brain electroencephalography and neural signal pathways and potential brain circuits across multiple brain regions.

[0061] In the second embodiment of the present invention, the stretching process of the microelectrode head was first simulated in COMSOL Multiphysics 5.6 to quantitatively characterize the force exerted on the magnetically controlled microelectrode in the magnetic field. By calculating the force applied to the head at different displacements, the magnitude of the force was found to be linearly proportional to the displacement of the head, confirming compliance with Hooke's Law. The estimated magnetic force applied to the head during the manipulation process was approximately 1 μN, a force comparable to the contractile force of a single cell. Then, a low-melting-point agarose hydrogel with a concentration of 0.6% wt was used as an in vitro model of animal brain tissue to simulate the controlled motion of the magnetically controlled flexible brain-computer interface fabricated in this embodiment in a magnetic field. After implantation of the magnetically controlled flexible electrode, an external magnetic field was applied, and the motion of the magnetically controlled flexible electrode under the action of the magnetic field was observed. The electrode's movement speed, controlled stretching, controlled turning, and other motion characteristics were tested. With precise manipulation of the magnetic field, the electrode bundle can be successfully manipulated to perform precise movements such as point-to-point directional aggregation, dispersion, forward movement, and deflection in vitro. Finally, a fresh pig brain was used as an in vitro model of animal brain tissue to simulate the controlled movement of the magnetically controlled flexible brain-computer interface fabricated in this embodiment in a magnetic field. The magnetically controlled flexible electrode fabricated in this embodiment can achieve basic movements such as movement, stretching, and deflection of the magnetically controlled microelectrode in isolated brain tissue under the manipulation of an external magnetic field.

[0062] In the third embodiment of this invention, a magnetically controlled flexible brain-computer interface (BCI) was used to collect neurophysiological signals from rats. Male Sprague-Dawley rats (7-8 weeks old, weighing 250-280g) were used in the animal experiments and housed in a room with a 12-hour light / dark cycle and free access to food and water. SD rats were anesthetized by intraperitoneal injection of urethane solution at a concentration of 0.2g / mL and fixed to a three-dimensional stereotaxic instrument. The rat's scalp was cut open, and connective tissue was bluntly dissected to fully expose the surface of the skull. A skull drill was used to slowly grind through the skull surface at a suitable location to create a small window area. The magnetically controlled flexible BCI of this invention was then implanted into the brain after vacuum drying. A magnetic field was used to precisely position the magnetically controlled flexible electrode to the target brain region and connect it to the NeuraLynx multichannel data acquisition system. After the rat's neurons recovered, the rat's brain neurophysiological signals were continuously recorded. The collected electrophysiological signals were imported into Spike 2 software for data analysis. Finally, the eight-channel EEG signals collected under rat anesthesia, along with detailed signals from one of the channels, were analyzed. The analysis results show that the magnetically controlled flexible brain-computer interface of this invention can detect the activity of regions of interest in the brain. It has the advantages of low signal interference between recording channels, good accuracy of electrical signal acquisition, stable electrical signal recording performance, and good stability of brain-computer interface. It can be used as a powerful tool in the field of neuroscience.

[0063] In the fourth embodiment of this invention, a magnetically controlled flexible brain-computer interface is used to collect neurophysiological signals of rats under regular drug stimulation. First, rats with perforated cranial window areas are prepared. The specific operation steps are the same as in the third embodiment. A magnetically controlled flexible brain-computer interface from this embodiment is combined with a micro-injection tube to create a neural platform capable of continuous drug delivery. The micro-injection tube is made using a glass capillary tube with an outer diameter of 1.5 mm and an inner diameter of 1.2 mm, fabricated using a thermo-stretching platform, with a tip outer diameter of approximately 25 μm. The micro-injection tube is connected to a micro-injector via a silicone tubing. Silicone oil or liquid paraffin is drawn up to fill the drug delivery line, and air is expelled. A 10 mM pentylenetetrazole (PTZ) solution is prepared using physiological saline as a solvent. Pentylenetetrazole is a commonly used drug for epilepsy modeling. Then, the micro-injector is connected to a micro-injection pump to draw up sufficient drug solution for later use. The micro-injection pump drug delivery program is set as follows: 5 μL per dose, 180 s interval, for a total of 8 doses. The electroencephalogram (EEG) signals of SD rats under drug stimulation were recorded, and the collected data were imported into Spike 2 software for analysis. The experiment revealed that under periodic drug stimulation, the rat EEG signals exhibited significant and regular changes. The waveforms of the electrical signals altered by PTZ stimulation were mostly spike waves, displaying clear characteristics of epileptic EEG. The results indicate that this invention provides a large-scale magnetically controlled flexible brain-computer interface capable of simultaneously recording data from distant brain regions, thereby enabling signal analysis of epileptic brains. In the future, higher-density electrode and optical or chemical interface locations can be explored within these spatially scalable magnetically controlled flexible electrodes to achieve larger recording or stimulation samples. This could lead to a leap forward in understanding brain circuits in inaccessible deep subcortical regions and contribute to the development of new treatments for various brain diseases, including epilepsy, Parkinson's disease, addiction, depression, and autism.

[0064] In summary, the embodiments of the present invention have the following advantages:

[0065] 1) This embodiment uses a magnetically controlled flexible electrode. Through the electrode core with magnetic particles, the electrode can be precisely controlled by a controllable magnetic field. The electrode shell is made of polylactic acid (PLA), which can provide a certain support for the electrode microfilaments and provide good biocompatibility after the electrode is implanted into the brain tissue.

[0066] 2) In this embodiment, a PVP coating is applied to the outside of the magnetically controlled flexible electrode to prepare a rigid and soluble PVP rigid shell. The PVP rigid shell enables rigid implantation and dissolves after implantation, thereby reducing the degree of damage to nerve tissue.

[0067] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order shown in the operation diagrams. For example, depending on the functions / operations involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flowcharts of this invention are provided by way of example to provide a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is altered and sub-operations described as part of a larger operation are executed independently.

[0068] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0069] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0070] The above is a detailed description of the preferred embodiments of the present invention, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A large-scale magnetically controlled flexible brain-computer interface, characterized in that, The device includes a printed circuit board, a flexible magnetron-controlled electrode, a reference electrode, and a rigid polyvinylpyrrolidone (PVP) shell. The printed circuit board connects the flexible magnetron-controlled electrode and the reference electrode, and the rigid PPVP shell surrounds the flexible magnetron-controlled electrode. The flexible magnetron-controlled electrode includes an electrode core, an electrode head, and an electrode shell. The electrode head is located at one end of the electrode core, and the electrode shell surrounds the electrode core. The printed circuit board includes a first electrical contact and a second electrical contact. The first electrical contact is used to connect the magnetron-controlled flexible electrode, and the second electrical contact is used to connect the reference electrode. The polyvinylpyrrolidone rigid shell provides rigidity for the electrode during implantation and degrades non-toxically after implantation. The flexible magnetically controlled electrode is used to move in a controlled manner in brain tissue under the control of an external magnetic field, and to locate in different brain regions, thereby acquiring local neuronal field potentials in different areas of the deep brain at the same time; the electrode head is modified with a magnetic nano-coating to be controlled by the magnetic field, which can expand the acquisition range of neuronal electrophysiological signals; the magnetically controlled flexible brain-computer interface also includes a connector, which is soldered to the interface of the printed circuit board, and the connector is used to connect the printed circuit board and the multi-channel signal acquisition system.

2. The large-scale magnetically controlled flexible brain-computer interface according to claim 1, characterized in that, The electrode core is made of flexible metallic or non-metallic material, including at least one of platinum-iridium alloy wire and conductive polymer fiber.

3. The large-scale magnetically controlled flexible brain-computer interface according to claim 1, characterized in that, The electrode head is made of magnetic microparticle material, including at least one of iron oxide spherical nanoparticles, neodymium iron boron microparticles, and iron cobalt nickel magnetic microparticles.

4. The large-scale magnetically controlled flexible brain-computer interface according to claim 1, characterized in that, The electrode housing comprises at least one of poly(L-lactic acid) and poly(glycolic acid) lactide.

5. A method for fabricating a large-scale magnetically controlled flexible brain-computer interface, characterized in that, include: Tubular molds are obtained by casting polymer fiber molds or metal wire molds using polydimethylsiloxane. The electrode wire is passed through the tubular mold, and a mixture of epoxy resin and magnetic particles is injected into the tubular mold. After the mixture solidifies, an electrode core with an electrode head is obtained. Poly-L-lactic acid is coated onto the electrode core with the electrode head to obtain a magnetically controlled flexible electrode. The magnetically controlled flexible electrode and the reference electrode are respectively connected to a printed circuit board, and the magnetically controlled flexible electrode is coated with a polyvinylpyrrolidone solution. After the polyvinylpyrrolidone solution is dried, a magnetically controlled flexible brain-computer interface is obtained. The process of using polydimethylsiloxane to cast polymer fiber molds or metal wire molds to obtain tubular molds includes: Using a metal wire as a template, the template is cast with PDMS and cured at 70°C for more than 4 hours. The metal wire is then extracted to obtain a PDMS cavity with an inner diameter equal to the diameter of the metal wire, thus preparing a tubular mold. The process of passing the electrode wire through the tubular mold and injecting a mixture of epoxy resin and magnetic particles into the tubular mold, followed by solidification of the mixture to obtain an electrode core with an electrode head, includes: The electrode wire is passed through the tubular mold to obtain the first mold; A mixture containing epoxy resin and magnetic particles is injected into the first mold to obtain a second mold; The second mold is magnetized in an axial parallel magnetic field. After the mixture solidifies, an electrode core with an electrode head is obtained.

6. The method for fabricating a large-scale magnetically controlled flexible brain-computer interface according to claim 5, characterized in that, The process of coating the electrode core with the electrode head with poly-L-lactic acid to obtain a magnetically controlled flexible electrode includes: Poly-L-lactic acid was melted using a thermoplastic method to obtain a poly-L-lactic acid melt. The electrode core with the electrode head is pulled out from the poly-L-lactic acid melt, so that the poly-L-lactic acid coats the electrode core with the electrode head, thus obtaining a magnetically controlled flexible electrode.

7. The method for fabricating a large-scale magnetically controlled flexible brain-computer interface according to claim 5, characterized in that, The polyvinylpyrrolidone solution was prepared using anhydrous ethanol as solvent and 15% polyvinylpyrrolidone by mass / volume as solute.

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