Wireless, battery-free brain stimulator and method of making

Abstract

The application provides a wireless and battery-free brain nerve stimulator and a preparation method. The brain nerve stimulator can be driven by a mobile phone loudspeaker, and a resonator designed can effectively amplify a piezoelectric signal. The brain nerve stimulator comprises two parts: a base provided with implantable nerve stimulation electrodes and a resonant cavity device connected through magnetic coupling. The design scheme of the brain nerve stimulator provides a general method for inhibiting epilepsy. The brain nerve stimulator can be extended to target brain deep layers or surface areas and peripheral nervous systems. A stimulation mode can be wirelessly transmitted and controlled. It is proved by electroencephalogram recording of free-moving mice that the wireless nerve stimulator can effectively relieve seizure events of the epileptic mice in vivo.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of brain nerve stimulation, in particular to a wireless and battery-free brain nerve stimulator and a preparation method thereof. BACKGROUND

[0002] Epilepsy is a common and devastating neurological disease. The treatment strategies for epilepsy are divided into three categories: drug treatment, epilepsy surgery and alternative treatment strategies (such as neural stimulation). As a forward-looking approach, in vivo neural stimulation is a new clinical treatment for the treatment of neuropsychiatric diseases, especially for drug-resistant patients. Among them, 30% to 40% of patients with epilepsy have drug resistance, and it has been found that electrical stimulation of the hippocampal dentate gyrus region (DGH) can inhibit seizures and save lives.

[0003] At present, the neural stimulation technology is difficult to meet the requirement of treating epilepsy anytime and anywhere. The treatment of large neural stimulation instruments in hospitals may miss the valuable opportunity for timely treatment, because the seizures are usually unpredictable. The existing portable neural stimulation device is to permanently implant a special wire or lead into a specific area of the brain, and the lead sends the current / voltage in the battery to the specific area of the brain to respond to the changes in the rhythm, frequency or amplitude of the brain electrical signals related to seizures, and to reduce the symptoms of epilepsy. However, the complications and failures of such implanted devices can be caused by lead breakage / device failure / battery disconnection / displacement, and can cause various adverse symptoms. At the same time, although the new type of epilepsy treatment instrument (CN216091870U) and epilepsy treatment cap (CN2315950Y) can achieve effective treatment, but its own versatility is poor, the volume is large, the operation is complex, and it is very inconvenient to use. It is difficult to improve the compliance of patient treatment, and affects the normal daily life of patients. Another neural electrical stimulation system based on radio technology is also used for epilepsy treatment (CN109646796A). However, the magnetic field generated by the radio system may cause unnecessary other additional potential risks to normal tissues / skin absorption and nervous system diseases.

[0004] Here, we invented a cell phone ringtone activated brain nerve stimulator for brain nerve stimulation. It has been proved that neural stimulation through the hippocampal dentate gyrus region (DGH) can effectively inhibit seizures in mice. The brain nerve stimulator realizes the conversion of cell phone ringtone sound energy into neural stimulation signal without the need of complex energy management and data processing devices. Our work has the advantages of convenient operation, low cost and long-term working neural stimulation, which can promote the development of portable clinical treatment of neuropsychiatric diseases. Therefore, we invented a new type of wireless and battery-free brain nerve stimulator for the treatment of drug-resistant nervous system diseases (epilepsy). SUMMARY

[0005] In view of the problems in the prior art, the application provides a novel portable nerve stimulation device (wireless and battery-free minimally invasive brain nerve stimulator). The wireless and battery-free minimally invasive brain nerve stimulator can convert mobile phone audio into a nerve stimulation signal for inhibiting epilepsy; the brain nerve stimulator with a connectable / detachable resonant cavity device can effectively collect piezoelectric energy to perform nerve stimulation; the passive brain nerve stimulator does not need external battery power supply at all, and the wireless and battery-free brain nerve stimulator can save the trouble of frequent battery replacement and the limitation of wired connection.

[0006] The wireless and battery-free brain nerve stimulator sequentially comprises a resonant cavity device and a base; the resonant cavity device comprises a resonant cavity upper part, a piezoelectric sheet, a signal modulation circuit, a resonant cavity lower part and a first magnetic column; the base comprises a flexible frame, a second magnetic column and an electric stimulation electrode; the resonant cavity upper part is used for converging sound energy; the piezoelectric sheet is used for converting sound energy into electric energy; the signal modulation circuit is used for converting electric energy into a nerve stimulation signal; the resonant cavity lower part is used for placing a circuit; the first magnetic column cooperates with the second magnetic column and is used for realizing electrical and physical connection of the resonant cavity device and the base; the flexible frame has biocompatibility and can be worn on the head; and the electric stimulation electrode is implanted in a specific brain area to perform nerve stimulation.

[0007] Preferably, the wireless and battery-free brain nerve stimulator is wirelessly powered by mobile phone audio, does not need external power supply or battery, and generates an electric signal for inhibiting epilepsy.

[0008] Preferably, the resonant cavity device and the base are connected to each other by a magnet.

[0009] Preferably, the signal modulation circuit processes electric energy converted by the mobile phone sound energy through the piezoelectric sheet into a corresponding nerve stimulation signal to achieve epilepsy inhibition.

[0010] Preferably, the resonant cavity upper part, the piezoelectric sheet, the signal modulation circuit and the resonant cavity lower part are integrated together and have a flexible biocompatible polydimethylsiloxane (PDMS) outer shell and an epoxy resin inner shell.

[0011] Preferably, the piezoelectric sheet comprises a lead zirconate titanate (PZT) thin film connected to the signal modulation circuit and can be driven by sound energy.

[0012] The application also relates to a preparation method of the wireless and battery-free brain nerve stimulator, comprising the following steps:

[0013] Step 1: The flexible outer shell of the resonant cavity device is manufactured from polydimethylsiloxane flexible material in a corresponding mold; the inner shell of the resonant cavity is made of epoxy resin hard glue material and covers the inside of the flexible outer shell.

[0014] Step 2, the piezoelectric sheet and signal modulation circuit are placed in the resonant cavity; the piezoelectric sheet is made of thin PZT film with Ag / Cu electrodes;

[0015] Step 3, the input end (Vin) of the flexible signal modulation circuit packaged by polydimethylsiloxane (PDMS) is connected to the piezoelectric sheet, and the output end (Vo) is connected to the cylindrical magnet at the bottom of the resonant cavity;

[0016] Step 4, the upper and lower parts of the resonant cavity are connected by adhesive;

[0017] Step 5, the base includes a flexible polydimethylsiloxane (PDMS) frame and a micron-level electric stimulation electrode; the flexible polydimethylsiloxane (PDMS) frame is manufactured in a mold; the stimulation electrode is made of two polytetrafluoroethylene insulated tungsten wires in a silicon tube;

[0018] Step 6, the flexible polydimethylsiloxane (PDMS) frame and the micron-level electric stimulation electrode are connected to the cylindrical magnet on the flexible base.

[0019] Preferably, the mold of the flexible polydimethylsiloxane (PDMS) frame is manufactured by 3D printing.

[0020] Preferably, the diameter of the silicon tube is 160-200 μm.

[0021] Preferably, the diameter of the polytetrafluoroethylene insulated tungsten wire is 60-80 μm.

[0022] The wireless battery-free brain nerve stimulator and the preparation method provided by the application have at least the following beneficial effects compared with the prior art:

[0023] (1) We combine the wireless nerve stimulator with in vivo electrophysiology to prove the therapeutic effect.

[0024] (2) The brain nerve stimulator based on the piezoelectric effect can be wirelessly operated by playing a ringtone on a mobile phone as energy and a selected nerve electric stimulation mode.

[0025] (3) The mobile phone ringtone can be directly converted into a nerve electric stimulation signal and sent to a specific brain area to participate in neural activity for treatment.

[0026] (4) By comparing the electroencephalogram and the corresponding time spectrum analysis during a seizure with and without nerve stimulation, it is proved that the acoustically driven brain nerve stimulator can effectively suppress seizures.

[0027] (5) After injecting the sea-alginic acid solution, the interictal large amplitude spike activity was observed from the high power electroencephalogram signal graph without providing the nerve stimulation. These results show that the epilepsy can be effectively induced after the sea-alginic acid solution delivery, and the electroencephalogram signal can obviously record the abnormal discharge activity of the brain during the seizure.

[0028] (6) Compared with the electroencephalogram signal waveform and power spectrum without the nerve stimulation, the strong ictal spike observed is less as the power decreases. These results show that the acoustically driven brain nerve stimulator can effectively suppress the seizure. BRIEF DESCRIPTION OF DRAWINGS

[0029] In the following, the present application will be described in more detail based on embodiments and with reference to the drawings. In which:

[0030] Figure 1 The schematic diagram of the brain nerve stimulator with flexible biocompatible package of the present application is shown;

[0031] Figure 2 The schematic diagram of the resonant cavity device and base connection of the present application is shown;

[0032] Figure 3 The principle diagram and physical details of the signal modulation circuit are shown;

[0033] Figure 4 The schematic diagram of the conversion of the acoustic energy signal into the piezoelectric signal and then into the nerve stimulation signal is shown;

[0034] Figure 5 The electroencephalogram signal and the corresponding time spectrum analysis during the seizure without the nerve stimulation are shown;

[0035] Figure 6 The electroencephalogram signal and the corresponding time spectrum analysis during the seizure with the brain nerve stimulator for nerve stimulation are shown. DETAILED DESCRIPTION

[0036] The present application will be further described in the following with reference to the drawings.

[0037] Reference Figure 1The present application provides a wireless and battery-free brain stimulator, mainly comprising two parts: a resonant cavity device and a base. The resonant cavity device further comprises a resonant cavity upper part 1 for converging acoustic energy; a piezoelectric sheet 2 for converting acoustic energy into electrical energy; a signal modulation circuit 3 for converting electrical energy into neural stimulation signals; a resonant cavity lower part 4 for placing the circuit; a pair of first magnetic columns 5 for realizing electrical and physical connection of the device and the base; a flexible frame 6 with biocompatibility, which can be worn on the head; a pair of second magnetic columns 7 for realizing electrical and physical connection of the device and the base; and a stimulation electrode 8 implanted in a specific brain area to perform neural stimulation. The resonant cavity device is integrated with a resonator, a piezoelectric sheet and a data processing unit. The designed resonant cavity device has a flexible biocompatible polydimethylsiloxane (PDMS) outer shell and an epoxy resin inner shell.

[0038] The piezoelectric sheet mainly comprises an extremely thin lead zirconate titanate piezoelectric ceramic (PZT) film (diameter: 8-9 mm; thickness: 100-150 microns) fixed with a copper sheet (diameter: 12.0-12.3 mm; thickness: 100-150 microns), which can be driven by the acoustic energy of a mobile phone ring. The piezoelectric sheet is connected to the data processing unit by a metal wire. The flexible custom integrated circuit with PDMS packaging serves as the data processing unit (diameter: 10-12 mm; thickness: 2.6-2.8 mm), and the bipolar piezoelectric signal is input into the circuit, and then the signal is strictly processed into the corresponding neural electrical stimulation signal. Two small magnets (diameter: 1.0-2.0 mm; height: 1.0-2.0 mm) are located at the bottom of the resonant cavity device for connection with the base.

[0039] The base is made of a flexible PDMS frame and micron-level neural electrical stimulation electrodes, which can be easily fixed on the skull through minimally invasive surgery.

[0040] The flexible PDMS frame contains two small magnets for connection with the resonant cavity device. A pair of polytetrafluoroethylene-coated tungsten wires (diameter: 60-80 microns) in a silicon tube (diameter: 160-200 microns) serve as the electrical stimulation electrodes and are connected to the magnets. The electrodes can be positioned and implanted in specific brain regions through surgical procedures.

[0041] As shown in Figure 2 The resonant cavity device and the base can be easily connected to each other by small magnets. The resonant cavity device can be quickly installed when it contacts the base due to the convenience of the installation / removal process (only need to be inserted). Only the base is left on the skin of the head during normal activities to avoid misoperation.

[0042] The brain nerve stimulator can be freely mounted / dismounted on the head of a mouse. The optimized design of the brain nerve stimulator is of great significance to the in-vivo nerve electrical stimulation system and minimally invasive surgical operation.

[0043] Figure 3 It is a schematic diagram and physical details of the signal modulation circuit. Figure 4 It is the conversion of acoustic energy signal into piezoelectric signal, and the signal input signal modulation circuit and then converted into electrical stimulation signal. The sinusoidal audio (6-7 kHz) is converted into a single-track square wave stimulation signal (100-130 Hz; pulse width 60-80 μs; 2.5-2.7 V; 0.25-0.27 mA).

[0044] The mobile phone audio can flexibly drive the stimulator to work in the customized working mode to provide the required treatment.

[0045] The application provides a preparation method of a wireless battery-free brain nerve stimulator.

[0046] Step 1, preparation of the resonant cavity device. The rigid structure of the resonant cavity device is printed by a 3D printer for molding, and the flexible shell is made of polydimethylsiloxane flexible material in the corresponding mold, wherein the flexible shell can be replaced by other biocompatible flexible materials, such as silicone and the like.

[0047] Step 2, the inner shell of the resonant cavity is covered with epoxy resin hard glue material, which belongs to hard resin material.

[0048] Step 3, the piezoelectric sheet and the signal modulation circuit are placed in the resonant cavity. The piezoelectric sheet is made of thin PZT film with Ag / Cu electrode, wherein the Ag electrode can be replaced by Cu or Al electrode.

[0049] Step 4, for the customized signal modulation circuit (flexible circuit packaged by PDMS), the input (Vin) is connected to the piezoelectric sheet, and the output (Vo) is connected to the cylindrical magnet at the bottom of the resonant cavity.

[0050] Step 5, the upper and lower parts of the resonant cavity are connected with instant adhesive.

[0051] Step 6, preparation of the base. The base is made of flexible PDMS frame and micron-level electrical stimulation electrode.

[0052] Step 7, the rigid structure of the base is printed by a 3D printer for molding, and the flexible frame is made of polydimethylsiloxane in the corresponding mold.

[0053] Step 8, the stimulating electrodes are made of two polytetrafluoroethylene insulated tungsten wires (diameter: 60-80 μm) in a silicon tube (diameter: 160-200 μm), and the stimulating electrodes can also be made of other biocompatible metal materials. Next, they are connected to the cylindrical magnet on the flexible base.

[0054] Step 9, the size of the base and the length of the stimulating electrodes can be prepared according to the actual situation of the organism.

[0055] In this embodiment, the structure of the wireless battery-free brain nerve stimulator is shown in Figure 1 for partial implantation in the body to achieve nerve stimulation and epilepsy suppression.

[0056] The battery-free wireless minimally invasive brain nerve stimulator can be wirelessly powered by mobile phone audio, without the need for external power supply or battery, and the generated electrical signal is used to suppress epilepsy. The brain nerve stimulator with biocompatibility not only meets the power supply requirement, but also realizes power supply by converting mobile phone sound energy into electrical energy, without the need to configure a battery and a long power cable, simplifying the overall structure.

[0057] The installation / demounting process of the wireless battery-free brain nerve stimulator in this embodiment is shown in Figure 2 The resonant cavity device and the base can be easily connected to each other by a small magnet. Since the installation / demounting process is very convenient, the resonant cavity device can be quickly installed when it contacts the base. Only the base is left on the skin of the head during normal activities to prevent misoperation.

[0058] The signal modulation circuit in the wireless battery-free brain nerve stimulator in this embodiment is shown in Figure 3 The nerve stimulation signal modulated by the circuit is shown in Figure 4 The sound energy signal generated by the mobile phone is processed by the signal modulation circuit to become the corresponding nerve stimulation signal, which is used to achieve epilepsy suppression.

[0059] By using the present application, the battery-free wireless brain nerve stimulator is realized to suppress seizures in a mouse model of epilepsy.

[0060] (1) We combined the wireless nerve stimulator with in vivo electrophysiology to prove the therapeutic effect.

[0061] (2) The brain nerve stimulator based on the piezoelectric effect can be wirelessly operated by playing a ringtone on a mobile phone as an energy source and a selected nerve electrical stimulation mode.

[0062] (3) The mobile phone ringtone can be directly converted into a nerve electrical stimulation signal and sent to a specific brain area to participate in neural activity for treatment.

[0063] (5) Figures 5-6Acoustically driven brain neurostimulator can effectively suppress seizures. The electroencephalogram (EEG) signals and corresponding time-frequency power spectrum during seizures with and without neurostimulation.

[0064] (4) Figure 5 The EEG signals and corresponding time-frequency power spectrum without providing electrical stimulation are shown. After injecting the sea salt alginate solution, the interictal high amplitude spike activity was observed from the high power EEG signal plot without providing neurostimulation. These results indicate that the seizures can be effectively induced after the delivery of the sea salt alginate solution, and the abnormal discharge activity of the brain during seizures can be clearly recorded by the EEG signals.

[0065] (5) Figure 6 The EEG signals and corresponding time-frequency power spectrum with the brain neurostimulator working are shown. Compared with the EEG signal waveform and power spectrum without neurostimulation, fewer strong ictal spikes were observed as the power decreased. These results indicate that the acoustically driven brain neurostimulator can effectively suppress seizures.

[0066] (6) These EEG results confirm the therapeutic effect of our brain neurostimulator on epileptic mice.

[0067] The present application provides a battery-free wireless brain neurostimulator to suppress a mouse seizure model.

[0068] Step 1, for in vivo electrophysiology of free-moving animals, the EEG recording electrode, drug delivery cannula and neurostimulation electrode were implanted into the mouse brain;

[0069] Step 2, the recording electrode was made of a single polytetrafluoroethylene-coated insulated tungsten wire (diameter: 60-80 μm). Two screws were placed on the dura mater above the frontal lobe and cerebellum, which were used as reference and ground electrodes, respectively;

[0070] Step 3, the recording electrode was placed just below the dura mater with coordinates: Anteroposterior (AP) -1.0-2.0 mm, Mediolateral (ML) +1.0-2.0 mm, and Dorsoventral (DV) -1.0-2.0 mm;

[0071] Step 4, a drug delivery cannula (180-200 μm) was assembled near the recording electrode for infusion of sea salt alginate solution to induce seizures;

[0072] Step 5, the drug delivery cannula was aimed at the target brain region with coordinates: AP -2.0-2.1 mm, ML +1.0-2.0 mm, and DV -1.5-1.8 mm;

[0073] Step 6, All electrodes and cannulae were protected and fixed on the skull using dental cement.

[0074] Step 7, To induce acute seizure, 100-120 nL of kainic acid solution was injected through the cannula using a micro-syringe pump controller for 3-5 minutes (20-40 nL / min).

[0075] Step 8, Electrophysiological recordings were started about 5-10 minutes after drug infusion. Electrical stimulation was performed 5-10 minutes after the start of EEG recording.

[0076] Example 2:

[0077] Referring to Figure 5 The method for constructing an epilepsy inhibition model based on a wireless and battery-free brain nerve stimulator includes the following steps:

[0078] Through the cooperation of the brain nerve stimulator and the mobile phone, an epilepsy inhibition system based on the wireless and battery-free brain nerve stimulator is formed. For in vivo electrophysiology of free-moving animals, a brain electrical signal recording electrode, a drug delivery cannula, and a nerve stimulation electrode are implanted in the mouse brain.

[0079] The recording electrode is made of a single polytetrafluoroethylene-coated insulated tungsten wire (diameter: 60-80 μm), and can also be made of other biocompatible metal materials.

[0080] Two screws are placed on the skull above the frontal lobe and the cerebellum, which are used as reference and ground electrodes, respectively.

[0081] The recording electrode is placed just below the dura mater, with coordinates of Anteroposterior (AP) -1.0-2.0 mm, Mediolateral (ML) +1.0-2.0 mm, and Dorsoventral (DV) -1.0-2.0 mm.

[0082] A drug delivery cannula (180-200 μm) is assembled near the recording electrode for infusion of kainic acid solution to induce epilepsy. The drug delivery cannula is aimed at the target brain region, with coordinates of AP -2.0-2.1 mm, ML +1.0-2.0 mm, and DV -1.5-1.8 mm.

[0083] All electrodes and cannulae are protected and fixed on the skull using dental cement.

[0084] To induce acute seizure, 100-120 nL of kainic acid solution is injected through the cannula using a micro-syringe pump controller for 3-5 minutes (20-40 nL / min).

[0085] Electrophysiological recordings were started about 5-10 minutes after drug infusion. Electrical stimulation was performed 5-10 minutes after the start of EEG recordings. Through the comparison of EEG, the brain nerve stimulator achieved epilepsy suppression on the mouse model.

[0086] Conclusions:

[0087] We invented a battery-free wireless acoustic-driven brain nerve stimulator for epilepsy suppression. It was demonstrated that a cell phone speaker can drive the nerve stimulator, and a designed resonator can effectively converge acoustic energy to amplify the piezoelectric signal. The brain nerve stimulator consists of two parts: a base with implantable nerve stimulation electrodes and a pluggable resonator cavity device connected by magnetic coupling. The design of the brain nerve stimulator provides a general method for epilepsy suppression. The brain nerve stimulator can be extended to target deep brain or surface area and peripheral nervous system. The stimulation pattern can be wirelessly transmitted and controlled by audio. We demonstrated that the wireless nerve stimulator can effectively alleviate the seizure events of epileptic mice through the EEG recordings of freely moving mice.

[0088] While the application has been described with reference to particular embodiments, it will be understood that the examples are merely for illustration and that many modifications can be made by persons skilled in the art. Other arrangements can be utilized and other methods can be devised without departing from the spirit and scope of the application as defined by the appended claims. It will be understood that the features described with reference to separate embodiments can be used in combination with other features described herein. It will be further understood that features described in relation to one example can be used in other examples.

Claims

1. A wireless, battery-free brain nerve stimulator, characterized in that, The brain nerve stimulator comprises a resonant cavity device and a base in sequence; the resonant cavity device includes an upper resonant cavity, a piezoelectric sheet, a signal modulation circuit, a lower resonant cavity, and a first magnetic column; the base includes a flexible frame, a second magnetic column, and electrical stimulation electrodes; The upper part of the resonant cavity is used to focus acoustic energy; Piezoelectric elements are used to convert sound energy into electrical energy; Signal modulation circuits are used to convert electrical energy into neural stimulation signals, including rectifier circuits, trigger circuits, and open-loop widening modulation circuits; The lower part of the resonant cavity is used to house the circuitry. The first and second magnetic pillars work together to achieve electrical and physical connections between the resonant cavity devices and the base. The flexible frame is biocompatible and can be worn on the head; Electrical stimulation electrodes are implanted in specific brain regions to perform neural stimulation; The wireless, battery-free brain nerve stimulator is wirelessly powered via mobile phone audio, requiring no external power source or battery. The generated nerve stimulation signals are used to suppress epilepsy. The resonant cavity device and the base are connected to each other by magnets; The signal modulation circuit processes the electrical signal converted from the mobile phone's acoustic signal by the piezoelectric element into a corresponding nerve stimulation signal to achieve epilepsy suppression. The upper part of the resonant cavity, the piezoelectric element, the signal modulation circuit, and the lower part of the resonant cavity are integrated together to form a resonant cavity device, which has a flexible biocompatible polydimethylsiloxane outer shell and an epoxy resin inner shell.

2. The wireless, battery-free brain stimulator according to claim 1, characterized in that, The piezoelectric element comprises a lead zirconate titanate piezoelectric ceramic film, which is connected to a signal modulation circuit and can be driven by acoustic energy.

3. The method for preparing the wireless, battery-free brain nerve stimulator according to claim 1, characterized in that, Includes the following steps: Step 1: The flexible outer shell of the resonant cavity device is manufactured from polydimethylsiloxane flexible material in a corresponding mold; the inner shell of the resonant cavity is made of epoxy resin hard plastic material, which covers the inside of the flexible outer shell. Step 2: The piezoelectric element and signal modulation circuit are placed in the resonant cavity; the piezoelectric element is made of a lead zirconate titanate piezoelectric ceramic film with Ag / Cu electrodes; Step 3: The input terminal of the flexible signal modulation circuit encapsulated with polydimethylsiloxane is connected to the piezoelectric sheet, and the output terminal is connected to the cylindrical magnet at the bottom of the resonant cavity. Step 4: The upper and lower parts of the resonant cavity are connected with adhesive; Step 5: The base includes a flexible polydimethylsiloxane frame and a micron-sized electrical stimulation electrode; the flexible polydimethylsiloxane frame is manufactured in a mold; the stimulation electrode is made of two polytetrafluoroethylene insulated tungsten wires in a silicon tube; Step 6: The flexible polydimethylsiloxane framework and micron-sized electrostimulation electrodes are connected to a cylindrical magnet on a flexible base.

4. The method for preparing the wireless, battery-free brain nerve stimulator according to claim 3, characterized in that, The mold for the flexible polydimethylsiloxane framework was manufactured by 3D printing.

5. The method for preparing the wireless, battery-free brain nerve stimulator according to claim 3, characterized in that, The diameter of the silicon tube is 160~200µm.

6. The method for preparing the wireless, battery-free brain nerve stimulator according to claim 3, characterized in that, The diameter of the polytetrafluoroethylene insulated tungsten wire is 60~80µm.

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