Flexible stretchable stimulating electrode and preparation method thereof

Abstract

The invention relates to the technical field of biological interface sensing, in particular to a flexible stretchable stimulation electrode and a preparation method thereof, and the electrode comprises a substrate, a conductive layer, an electrode path packaging layer and a stimulation point packaging layer; the conductive layer is composed of a liquid metal electrode array arranged on the substrate; the conductive layer comprises an electrode wire area and an electrode stimulation end; the electrode channel packaging layer covers the electrode wire area. The packaging layer at the stimulation point covers the electrode stimulation end; the electrode path packaging layer is made of polydimethylsiloxane; and the packaging layer at the stimulation point is made of a polydimethylsiloxane-carbon fiber composite elastomer. The invention aims to provide a flexible stretchable stimulating electrode so as to solve the technical problems of mechanical mismatching, unstable biological interface, insufficient stimulating accuracy and the like in the long-term use process of the existing stimulating electrode.

Description

Technical Field

[0001] The present application relates to the field of biointerface sensing technology, and in particular to a flexible and stretchable stimulation electrode and a preparation method thereof. Background Art

[0002] With the rapid development of wearable medical electronics, electronic skin, neural interfaces, and intelligent rehabilitation technologies, flexible and stretchable stimulation electrodes, as key components in human-computer interfaces, have attracted widespread attention. These electrodes must not only achieve excellent fit and comfort on complex biological surfaces (such as skin, muscle, or neural tissue), but also maintain stable electrical stimulation performance and biocompatibility under mechanical deformation conditions such as dynamic stretching, bending, and torsion.

[0003] Although traditional rigid metal electrodes offer excellent electrical conductivity, their high mechanical rigidity and modulus mismatch with human tissue can easily lead to stimulation position deviation, signal instability, skin discomfort, and even micro-damage during long-term use, limiting their application in wearable and implantable neuromodulation. Therefore, the development of flexible, stretchable electrodes with good mechanical compliance, excellent electrical conductivity, and reliable electrical stimulation has become an important research direction in this field.

[0004] Existing skin stimulation electrode technology, when applied to the human skin surface or in flexible wearable devices, still has the following significant drawbacks, which seriously restrict its application in clinical rehabilitation, electrophysiological intervention, and wearable medical systems: (1) Large electrode size and limited spatial resolution: Traditional stimulation electrodes are usually designed with a larger area to reduce unit area impedance and enhance adhesion, but this results in a decrease in their spatial positioning ability and makes it impossible to achieve precise stimulation of specific muscle groups or nerve areas.

[0005] (2) The electrode structure is very rigid, non-stretchable, and has poor adaptability: Most existing electrodes are made of rigid conductive materials such as stainless steel, platinum, and iridium. They lack flexibility and elasticity, and there is a huge modulus difference between them and soft human tissues. During long-term use, they are likely to cause damage to surrounding tissues, thereby reducing the stability and comfort of stimulation.

[0006] (3) Insufficient precision of electrical stimulation makes it difficult to achieve efficient neural regulation: Due to uneven contact, unstable signal coupling, and diffusion of stimulation current caused by structural rigidity, existing electrodes have poor stimulation selectivity in multi-target or fine neural control, making it difficult to meet the demand for high-precision, personalized electrical stimulation solutions, limiting their application in high-demand scenarios such as precision rehabilitation treatment and functional reconstruction. Summary of the Invention

[0007] The embodiments of the present application provide a flexible and stretchable stimulation electrode and a preparation method thereof to solve technical problems such as mechanical mismatch, biointerface instability, and insufficient stimulation accuracy that exist in existing stimulation electrodes during long-term use.

[0008] To solve the above technical problems, in the first aspect, an embodiment of the present application provides a flexible and stretchable stimulation electrode, comprising: a substrate, a conductive layer, an electrode path packaging layer and a stimulation point packaging layer; the conductive layer is composed of a liquid metal electrode array arranged on the substrate; the conductive layer includes an electrode wire area and an electrode stimulation end; the electrode path packaging layer covers the electrode wire area; the stimulation point packaging layer covers the electrode stimulation end; the material of the electrode path packaging layer is polydimethylsiloxane; the material of the stimulation point packaging layer is polydimethylsiloxane-carbon fiber composite elastomer.

[0009] In some exemplary embodiments, the liquid metal electrode array is composed of ultrasonically treated gallium-based liquid metal microsphere particles.

[0010] In some exemplary embodiments, the electrode path packaging layer covers the electrode lead area while exposing the electrode stimulation end, thereby preventing body fluids from corroding the lead and improving biocompatibility; the thickness of the electrode path packaging layer is 50-100 μm.

[0011] In some exemplary embodiments, the thickness of the electrode is 0.1 mm to 0.3 mm and has a certain degree of stretchability.

[0012] In some exemplary embodiments, the material of the substrate is polydimethylsiloxane.

[0013] In the second aspect, an embodiment of the present application also provides a method for preparing a flexible and stretchable stimulation electrode, comprising the following steps: providing a substrate; forming a conductive layer on the substrate; the conductive layer is composed of a liquid metal electrode array; the conductive layer includes an electrode wire area and an electrode stimulation end; the electrode wire area and the electrode stimulation end of the conductive layer are respectively encapsulated to form an electrode path encapsulation layer and a stimulation point encapsulation layer; the material of the electrode path encapsulation layer is polydimethylsiloxane; the material of the stimulation point encapsulation layer is polydimethylsiloxane-carbon fiber composite elastomer.

[0014] In some exemplary embodiments, forming a conductive layer on a substrate includes: preparing liquid metal micro-nanoparticle ink; printing an electrode pattern on a PET film using screen printing; and transferring the electrode pattern from the PET film to the substrate using a transfer method using the liquid metal micro-nanoparticle ink.

[0015] In some exemplary embodiments, the electrode wire area of ​​the conductive layer is encapsulated to form an electrode path encapsulation layer, including: using a glue spreader to prepare a 50μm~100μm thick polydimethylsiloxane film, and covering the electrode stimulation point and the rear-end wiring with the polydimethylsiloxane film; then using the glue spreader to spin-coat a 50μm thick layer of polydimethylsiloxane on the electrode surface as an encapsulation layer, and the spin coating speed parameter is set to 600 rpm / 60 s. After the spin coating is completed, the thin film covering the electrode stimulation point is peeled off, and the electrode is placed in a 60°C oven to dry for 2 hours. After the polydimethylsiloxane is cured, the electrode path encapsulation layer is formed.

[0016] In some exemplary embodiments, the electrode stimulation end is encapsulated to form an encapsulation layer at the stimulation point, including: using a planetary mixer to mix and remove bubbles with a mass fraction of 15% carbon fiber and polydimethylsiloxane, and adding a curing agent after mixing evenly to obtain an uncured polydimethylsiloxane-carbon fiber composite elastomer; according to the size of the encapsulation layer at the desired stimulation point, a UV laser marking machine is used to make a mask, and the uncured composite elastomer material is evenly covered on the surface of the electrode stimulation point by a scraping method; after the scraping is completed, the electrode is placed in a 60°C oven and dried for 2 hours to form an encapsulation layer at the stimulation point.

[0017] In some exemplary embodiments, the mass ratio of polydimethylsiloxane to the curing agent is 15:1.

[0018] The technical solution provided by the embodiments of the present application has at least the following advantages: An embodiment of the present application provides a flexible and stretchable stimulation electrode and a preparation method thereof, wherein the electrode comprises: a substrate, a conductive layer, an electrode path encapsulation layer, and a stimulation point encapsulation layer; the conductive layer is composed of a liquid metal electrode array arranged on the substrate; the conductive layer includes an electrode wire area and an electrode stimulation end; the electrode path encapsulation layer covers the electrode wire area; the stimulation point encapsulation layer covers the electrode stimulation end; the material of the electrode path encapsulation layer is polydimethylsiloxane; the material of the stimulation point encapsulation layer is polydimethylsiloxane-carbon fiber composite elastomer.

[0019] This application provides a flexible, stretchable stimulation electrode. This electrode uses PDMS as a substrate and gallium-based liquid metal as a conductive material. By encapsulating a layer of conductive elastic composite material on the stimulation point surface and then electrodepositing a layer of conductive polymer, it achieves excellent electrode performance. The electrode has an overall thickness of approximately 0.3 mm and exhibits a certain degree of stretchability, maintaining good stimulation efficiency even under large deformations. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] One or more embodiments are exemplarily described by the pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.

[0021] Figure 1 A schematic structural diagram of a flexible and stretchable stimulation electrode provided in one embodiment of the present application.

[0022] Figure 2 A schematic diagram of the impedance change of an electrode provided in an embodiment of the present application within a frequency range of 1-100 kHz.

[0023] Figure 3 This is a schematic diagram of the cyclic voltammetry (CV) characteristic curve of the electrode provided in an embodiment of the present application in the range of -1V to -1V. DETAILED DESCRIPTION

[0024] As can be seen from the background technology, traditional rigid metal electrodes have high mechanical rigidity and modulus mismatch with human tissue, which can easily lead to stimulation position deviation, signal instability or skin discomfort, and even cause micro-damage during long-term use, limiting their application in wearable and implantable neural regulation.

[0025] The related technology provides a liquid metal-based implantable soft neural electrode for deep brain stimulation, demonstrating an implantable soft macroscopic electrode made of biocompatible liquid metal for brain stimulation. These probes can be easily manufactured by simply filling liquid metal into a polymer tube, providing a direct method for manufacturing brain stimulation devices. They can be customized to different lengths and diameters and can also be used as recording microelectrodes. The electrode tip is treated with platinum nanoclusters, which achieves low impedance and efficient charge injection while preventing liquid metal from penetrating into brain tissue. In in vivo experiments in a rat model of neuropathic pain, the stability and effectiveness of these probes in simultaneous neural stimulation and recording were demonstrated.

[0026] Another related technology provides an ultra-high stretchable and dynamically deformable electronic device for monitoring organs in dynamic motion, and introduces a scalable manufacturing method for creating intrinsically stretchable and implantable electronic devices. These devices use liquid metal components with ultra-high stretchability of up to 400% tensile strain and excellent resistance to repeated deformation. The device architecture also shows long-term stability under physiological conditions, can achieve a close connection with internal organs, and has low interface impedance. The successful electrophysiological mapping of a rapidly beating heart demonstrated the potential of intrinsically stretchable electronic devices in a wide range of applications such as health monitoring, disease diagnosis, and medical treatment.

[0027] In applications such as neuromodulation, muscle function rehabilitation, and pain management, it is crucial to achieve efficient and safe electrical stimulation of the human body. When traditional rigid stimulation electrodes come into contact with skin or tissue, due to the significant modulus difference between mechanical rigidity and human tissue, they often lead to stimulation position offset, unstable electrical contact, and even tissue discomfort, especially in dynamic motion states. Therefore, this application aims to develop a new type of stretchable flexible stimulation electrode to achieve stable, accurate, and comfortable electrical stimulation output to specific areas of the human body. This application needs to solve the following key technical problems: (1) Develop stretchable flexible stimulation electrodes with high conductivity, high stretchability, and excellent biocompatibility to achieve stable electrical stimulation output under large strain conditions; (2) Construct a low-impedance, long-term adhered skin-electrode interface structure to reduce interface resistance and improve stimulation efficiency and safety.

[0028] To address the above technical issues, the present invention provides a flexible and stretchable stimulation electrode, comprising: a substrate, a conductive layer, an electrode path encapsulation layer, and a stimulation point encapsulation layer; the conductive layer is composed of a liquid metal electrode array disposed on the substrate; the conductive layer includes an electrode wire region and an electrode stimulation terminal; the electrode path encapsulation layer covers the electrode wire region; the stimulation point encapsulation layer covers the electrode stimulation terminal; the electrode path encapsulation layer is made of polydimethylsiloxane; and the stimulation point encapsulation layer is made of a polydimethylsiloxane-carbon fiber composite elastomer. The present invention provides a flexible and stretchable stimulation electrode and a method for preparing the same, to address technical issues with existing stimulation electrodes during long-term use, such as mechanical mismatch, biointerface instability, and insufficient stimulation accuracy.

[0029] The following detailed description of the various embodiments of the present application is provided in conjunction with the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in the various embodiments of the present application to facilitate a better understanding of the present application. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.

[0030] See Figure 1 The embodiment of the present application provides a flexible and stretchable stimulation electrode, including: a substrate 1, a conductive layer 2, an electrode path packaging layer 3 and a stimulation point packaging layer 4; the conductive layer 2 is composed of a liquid metal electrode array arranged on the substrate 1; the conductive layer 2 includes an electrode wire area and an electrode stimulation end; the electrode path packaging layer 3 covers the electrode wire area; the stimulation point packaging layer 4 covers the electrode stimulation end; the material of the electrode path packaging layer 3 is polydimethylsiloxane; the material of the stimulation point packaging layer 4 is polydimethylsiloxane-carbon fiber composite elastomer.

[0031] The purpose of this application is to provide a flexible, stretchable stimulation electrode to address technical issues such as mechanical mismatch, biointerface instability, and insufficient stimulation accuracy that exist with existing stimulation electrodes during long-term use. Traditional implantable electrodes often use metal wires or rigid electrode structures. These electrodes are prone to interfacial stress concentration in dynamic physiological environments (such as muscle contraction and organ movement), leading to tissue damage, inflammatory reactions, or electrode migration, thereby affecting stimulation effectiveness and biocompatibility, limiting their application in areas such as neural regulation, cardiac pacing, and spinal cord stimulation.

[0032] In some embodiments, the liquid metal electrode array is composed of ultrasonically treated gallium-based liquid metal microsphere particles.

[0033] In some embodiments, the electrode path packaging layer 3 covers the electrode wire area while exposing the electrode stimulation end to prevent body fluid from corroding the wire and improve biocompatibility; the thickness of the electrode path packaging layer 3 is 50-100 μm.

[0034] In some embodiments, the thickness of the electrode is 0.1 mm to 0.3 mm and has a certain degree of stretchability.

[0035] In some embodiments, the material of the substrate 1 is polydimethylsiloxane.

[0036] An embodiment of the present application also provides a method for preparing a flexible and stretchable stimulation electrode, comprising the following steps: providing a substrate; forming a conductive layer on the substrate; the conductive layer is composed of a liquid metal electrode array; the conductive layer includes an electrode wire area and an electrode stimulation end; the electrode wire area and the electrode stimulation end of the conductive layer are respectively encapsulated to form an electrode path encapsulation layer and a stimulation point encapsulation layer; the material of the electrode path encapsulation layer is polydimethylsiloxane; the material of the stimulation point encapsulation layer 4 is polydimethylsiloxane-carbon fiber composite elastomer.

[0037] In some embodiments, forming a conductive layer on a substrate includes: preparing liquid metal micro-nanoparticle ink; using screen printing to print an electrode pattern on a PET film; and using liquid metal micro-nanoparticle ink to transfer the electrode pattern from the PET film to the substrate by a transfer method.

[0038] In some embodiments, the electrode wire area of ​​the conductive layer is encapsulated to form an electrode path encapsulation layer, including: using a glue spreader to prepare a 50μm~100μm thick polydimethylsiloxane film, and covering the electrode stimulation point and the rear-end connection with the polydimethylsiloxane film; then using the glue spreader to spin-coat a 50μm thick layer of polydimethylsiloxane on the surface of the electrode as an encapsulation layer, and the spin coating speed parameter is set to 600 rpm / 60 s. After the spin coating is completed, the thin film covering the electrode stimulation point is peeled off, and the electrode is placed in a 60°C oven to dry for 2 hours. After the polydimethylsiloxane is cured, the electrode path encapsulation layer is formed.

[0039] In some embodiments, the electrode stimulation end is encapsulated to form an encapsulation layer at the stimulation point, including: using a planetary mixer to mix 15% by mass of carbon fiber and polydimethylsiloxane to remove bubbles, and after mixing evenly, adding a curing agent to obtain an uncured polydimethylsiloxane-carbon fiber composite elastomer; according to the size of the encapsulation layer at the desired stimulation point, a UV laser marking machine is used to make a mask, and the uncured composite elastomer material is evenly covered on the surface of the electrode stimulation point by a scraping method; after the scraping is completed, the electrode is placed in a 60°C oven to dry for 2 hours to form an encapsulation layer at the stimulation point.

[0040] In some embodiments, the mass ratio of polydimethylsiloxane to curing agent is 15:1.

[0041] The flexible and stretchable stimulation electrode and its preparation method provided by the present application are introduced in detail below through specific examples.

[0042] The flexible stretchable stimulation electrode provided by the present application, such as Figure 1 As shown in the figure, from bottom to top, they include: a substrate (PMDS), a conductive layer (EGaln), an electrode path encapsulation layer (PMDS), and an encapsulation layer at the stimulation point (composite carbon fiber elastomer). The substrate is made of the commercial elastomer polydimethylsiloxane (PDMS). Specifically, a layer of PMDS is spin-coated by transfer printing to form the substrate layer. At the same time, the flexibility of the substrate ensures that the electrode can fit well on the tissue surface (such as nerve fibers). The electrode conductive layer: It is composed of ultrasonically treated gallium-based liquid metal microspheres. When not activated, the conductive layer is in a non-conductive state. After activation, the resistance quickly drops to within 100 ohms, and it has very good conductivity.

[0043] Encapsulation layer: Use 50-100μm thick PDMS to cover the electrode wire area, exposing only the electrode stimulation end to prevent body fluid corrosion of the wire and improve biocompatibility.

[0044] Encapsulated conductive layer at the stimulation point: This elastic composite layer performs triple functions: conductivity, stretchability, and encapsulation. First, its excellent conductivity allows it to serve as an electrical stimulation interface for tissue, enabling stable electrical signal transmission. Second, its excellent stretchability and compliance buffer stress changes caused by tissue movement, improving fit and stimulation stability. Third, it acts as a physical barrier to the liquid metal conductive layer, effectively preventing liquid metal leakage and direct contact with biological tissue, enhancing the biosafety of the electrode.

[0045] The present application provides a method for preparing a flexible stretchable stimulation electrode, comprising the following steps: Preparation of liquid metal micro-nanoparticle ink: 6 g of gallium-indium alloy (EGaIn, 75% gallium, 25% indium) and 1 mL of n-decanol were weighed using an electronic balance and added to a 10 mL centrifuge tube. Ultrasonic cell disruptor was used for 3-5 minutes at 50% amplitude. The entire sonication process was performed in a water bath to prevent volatilization of the n-decanol caused by heating. An ultrasonic horn with a diameter of 5 mm or 1 cm was inserted 1 cm below the n-decanol liquid surface for sonication. A 2-second pulse and 2-second pause pattern was used to minimize instrument damage caused by high temperatures. Under ultrasound, the liquid metal was transformed from a continuous state into micro-nanoparticles, resulting in a suspension of liquid metal particles in n-decanol, which was then prepared as the liquid metal ink for screen printing.

[0046] Preparation of liquid metal electrode arrays: A 200-mesh screen printing mask was used to ensure the accuracy of the neural electrode pattern. The screen and squeegee were cleaned with anhydrous ethanol and air-dried before use. The screen was mounted on a manual screen printer. A polyethylene terephthalate (PET) film was adhered to the printing plate using medical tape to serve as the printing substrate. Liquid metal micro- and nanoparticle ink, prepared by ultrasonication, was then dripped onto the edge of the screen and screen-printed. The printed electrode pattern was placed in a well-ventilated area to dry, removing any residual n-decanol solvent from the electrode pattern. This resulted in a liquid metal particle neural electrode pattern. A polymethylsiloxane solution (PDMS; PDMS to curing agent ratio of 15:1) was poured onto the surface of the neural electrode pattern using a coating machine at 600 rpm for 60 seconds to achieve the desired electrode substrate thickness. After coating, the surface was allowed to stand for 30 minutes to 1 hour to allow the PDMS solution and liquid metal micro- and nanoparticles to fully coat the surface. The electrode sample was placed in a 60°C oven and dried for 2 hours to allow the PDMS to solidify. The PDMS film was peeled off from the PET substrate to obtain the liquid metal electrode array transferred to the PDMS substrate.

[0047] Electrode encapsulation: PDMS and PDMS-carbon fiber composite elastomer are used as electrode encapsulation materials for different applications. For the insulating encapsulation of the conductive path, PDMS with matching tensile properties is selected as the encapsulation material. A 50-100μm thick PDMS film is pre-prepared using a glue spreader and covered at the stimulation point and rear-end connection. A 50μm thick PDMS layer is then spin-coated on the electrode surface using a glue spreader at a speed of 600 rpm for 60 seconds. After spin coating, the thin film covering the electrode stimulation point is peeled off and the electrode is dried in a 60°C oven for 2 hours. After the PDMS solidifies, the encapsulated stretchable stimulation electrode is obtained. For the insulating encapsulation at the stimulation point, a PDMS-carbon fiber composite elastomer is selected as the encapsulation material. A planetary mixer was used to mix 15% carbon fiber and PDMS, removing bubbles. After uniform mixing, a curing agent was added (PDMS:curing agent ratio of 15:1) to produce an uncured PDMS-carbon fiber composite elastomer. A mask was prepared using a UV laser marker to create the desired size of the encapsulation layer at the desired stimulation point. The uncured composite elastomer was then evenly applied to the stimulation point using a doctor blade. After doctor blade application, the electrode was dried in a 60°C oven for 2 hours to obtain the encapsulated electrode.

[0048] Conductive polymer deposition: Polypyrrole electrodeposition was performed using a three-electrode system, with a stretchable stimulation electrode array as the working electrode, a platinum sheet as the counter electrode, and an Ag / AgCl electrode as the reference electrode. 300 μL of distilled pyrrole monomer was added to 45 mL of an electrodeposition solution containing 0.3 M sodium dodecylbenzenesulfonate and 0.1 M p-toluenesulfonic acid and stirred. The solution was then sonicated in a water bath for 30 minutes to ensure homogeneity. Electrochemical deposition was performed at a constant voltage of 0.8 V for 400 seconds at 0°C (ice bath). The resulting electrode was rinsed three times with deionized water and then with anhydrous ethanol to obtain a usable finished electrode.

[0049] The improvements of this application mainly include the following aspects: (1) Flexible and stretchable electrode structure design: The overall electrode structure of this application has good flexibility and stretchability, can adapt to the dynamic deformation of tissue in the implantation environment, and maintain long-term stable tissue adhesion and electrical stimulation performance.

[0050] (2) Stimulation interface layer composed of conductive elastic composite material: A layer of elastic composite material with good conductivity and mechanical flexibility is set at the stimulation point to serve as the contact interface for electrical stimulation output, while improving stress adaptability and interface stability.

[0051] (3) Liquid metal conductive core and its packaging isolation structure: Liquid metal is used as the main conductive channel inside the electrode, and the conductive elastic material covering it is used to conduct electrical signals and physically isolate it, preventing the liquid metal from leaking and directly contacting the tissue, thereby improving the biosafety of the implant system.

[0052] (4) Composition and configuration of the conductive material system: Use composite conductive materials with high conductivity and good mechanical flexibility, such as carbon nanotube-PDMS composite materials.

[0053] (5) Electrode base material: The electrode base material is commercial PDMS silicone, which is a flexible electrode raw material with medical material grade.

[0054] (6) Transfer method: During the production process of the stretchable stimulation electrode produced by this invention, a transfer method is used to transfer the electrode pattern from the PET film material to the PDMS flexible substrate.

[0055] (7) Packaging material: The stretchable stimulation electrode described in this application is packaged with an ultra-thin film in all areas except the exposed portion of the electrode to avoid leakage. The packaging layer material selected is a micron-thick film material with good biocompatibility and good insulation properties.

[0056] (8) Multi-channel design: The stretchable stimulation electrode described in this application is a multi-channel design with 1 to 100 channels, preferably 2 to 50 channels, and can be processed by screen printing combined with transfer printing.

[0057] This application has been proven to be feasible through experiments and use. Figure 2 and Figure 3 As shown, the impedance of the electrode is low, and it can be seen from the cyclic voltammetry (CV) curve that it has good charge storage capacity. In the experiment, the electrode was able to stably adhere to the surface of the nerve and induce obvious physiological responses in mice after applying an electrical signal, indicating that the electrode has good electrical stimulation function. In addition, during multiple repeated stimulations, the electrode remained stably conductive without mechanical damage or signal attenuation, showing excellent conductive stability and mechanical compliance. No obvious inflammatory response was observed in tissue observation, which further proves the biocompatibility and safety of this application, indicating that it has good practical application prospects in implantable applications such as neural regulation.

[0058] The flexible and stretchable multi-channel stimulation electrode provided in this application has obvious advantages over the existing technology in terms of functional integration, structural compliance and electrical performance, which are specifically reflected in the following aspects: (1) Multi-channel array design to improve the spatial precision and functional flexibility of neural regulation This application utilizes a multi-channel electrode array structure, which can be designed in linear arrangements, two-dimensional matrices, or circular distributions, depending on the application requirements, to achieve independent or coordinated electrical stimulation control of multiple target tissue regions. Compared to traditional single-channel or low-channel electrodes, this significantly improves spatial resolution and flexibility of stimulation schemes, making it particularly suitable for scenarios such as complex neural network regulation, large-scale functional restoration, and high-precision disease model research.

[0059] (2) Constructing an ultra-thin patch structure to enhance tissue adhesion and signal stability The overall thickness of the electrode is less than 500 μm, and its soft and compliant structure allows for close contact with the surfaces of soft tissues such as the brain, myocardium, and spinal cord. This patch structure not only effectively reduces the mechanical mismatch between tissue and electrode, but also mitigates interfacial stress changes caused by tissue movement (such as pulsation and peristalsis), reducing problems such as electrode detachment and displacement, thereby improving mechanical stability during long-term implantation.

[0060] (3) Introducing liquid metal conductive materials to achieve the coordinated unity of high conductivity and high stretchability This application introduces gallium-based liquid metal particles that have been ultrasonically treated and microspheroidized into the conductive path. In the unactivated state, they are insulating. After sintering and activation, their resistance drops sharply to the 100-ohm level, ensuring efficient electrical signal transmission. Furthermore, this liquid metal conductor maintains low resistivity changes under large deformation conditions such as stretching and bending, far superior to traditional rigid metal or silver nanowire conductors, making it particularly suitable for implantable organ electrical stimulation scenarios in dynamic environments.

[0061] Based on the above technical solution, the embodiment of the present application provides a flexible and stretchable stimulation electrode and a preparation method thereof, wherein the electrode includes: a substrate, a conductive layer, an electrode path packaging layer and a stimulation point packaging layer; the conductive layer is composed of a liquid metal electrode array arranged on the substrate; the conductive layer includes an electrode wire area and an electrode stimulation end; the electrode path packaging layer covers the electrode wire area; the stimulation point packaging layer covers the electrode stimulation end; the material of the electrode path packaging layer is polydimethylsiloxane; the material of the stimulation point packaging layer is polydimethylsiloxane-carbon fiber composite elastomer.

[0062] This application provides a flexible, stretchable stimulation electrode. This electrode uses PDMS as a substrate and gallium-based liquid metal as a conductive material. By encapsulating a layer of conductive elastic composite material on the stimulation point surface and then electrodepositing a layer of conductive polymer, it achieves excellent electrode performance. The electrode has an overall thickness of approximately 0.3 mm and exhibits a certain degree of stretchability, maintaining good stimulation efficiency even under large deformations.

[0063] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present application, and that in actual applications, various changes in form and detail may be made thereto without departing from the spirit and scope of the present application. Any person skilled in the art may make changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be subject to the scope defined in the claims.

Claims

1. A flexible and stretchable stimulation electrode, characterized in that: include: substrate, conductive layer, electrode path encapsulation layer and stimulation point encapsulation layer; The conductive layer is composed of a liquid metal electrode array arranged on the substrate; the conductive layer includes an electrode wire area and an electrode stimulation end; The electrode path packaging layer covers the electrode wire area; the packaging layer at the stimulation point covers the electrode stimulation end; The material of the electrode path packaging layer is polydimethylsiloxane; the material of the packaging layer at the stimulation point is polydimethylsiloxane-carbon fiber composite elastomer.

2. The flexible stretchable stimulation electrode according to claim 1, characterized in that: The liquid metal electrode array is composed of ultrasonically treated gallium-based liquid metal microsphere particles.

3. The flexible stretchable stimulation electrode according to claim 1, characterized in that: The electrode path encapsulation layer covers the electrode wire area while exposing the electrode stimulation end, thereby preventing body fluids from corroding the wire and improving biocompatibility; The thickness of the electrode path packaging layer is 50-100 μm.

4. The flexible stretchable stimulation electrode according to claim 1, characterized in that: The thickness of the electrode is 0.1mm~0.3mm.

5. The flexible stretchable stimulation electrode according to claim 1, characterized in that: The material of the substrate is polydimethylsiloxane.

6. A method for preparing a flexible stretchable stimulation electrode, characterized in that: The following steps are involved: providing a substrate; forming a conductive layer on the substrate; the conductive layer is composed of a liquid metal electrode array; the conductive layer includes an electrode wire area and an electrode stimulation end; The electrode wire area and the electrode stimulation end of the conductive layer are respectively encapsulated to form an electrode path encapsulation layer and a stimulation point encapsulation layer; the material of the electrode path encapsulation layer is polydimethylsiloxane; the material of the stimulation point encapsulation layer is polydimethylsiloxane-carbon fiber composite elastomer.

7. The method for preparing a flexible stretchable stimulation electrode according to claim 6, wherein: forming a conductive layer on the substrate, comprising: Preparation of liquid metal micro-nanoparticle ink; Electrode patterns were printed on PET films using screen printing; Liquid metal micro-nano particle ink is used to transfer the electrode pattern from the PET film to the substrate through a transfer method.

8. The method for preparing a flexible stretchable stimulation electrode according to claim 6, wherein: The electrode lead area of ​​the conductive layer is encapsulated to form an electrode path encapsulation layer, including: A 50μm~100μm thick polydimethylsiloxane film was prepared using a coater, and the polydimethylsiloxane film was covered on the electrode stimulation point and the rear-end wiring; then a 50μm thick layer of polydimethylsiloxane was spin-coated on the electrode surface using a coater as an encapsulation layer, and the spin coating speed parameter was set to 600 rpm / 60 s. After the spin coating was completed, the thin film covering the electrode stimulation point was peeled off, and the electrode was placed in a 60℃ oven to dry for 2 hours. After the polydimethylsiloxane was cured, an electrode path encapsulation layer was formed.

9. The method for preparing a flexible stretchable stimulation electrode according to claim 6, wherein: The electrode stimulation end is encapsulated to form an encapsulation layer at the stimulation point, including: A planetary mixer was used to mix and remove bubbles from carbon fiber and polydimethylsiloxane with a mass fraction of 15%. After mixing evenly, a curing agent was added to obtain an uncured polydimethylsiloxane-carbon fiber composite elastomer. A UV laser marking machine was used to make a mask according to the size of the encapsulation layer at the desired stimulation point, and the uncured composite elastomer material was evenly covered on the surface of the electrode stimulation point by scraping. After scraping, the electrode was placed in a 60°C oven and dried for 2 hours to form an encapsulation layer at the stimulation point.

10. The method for preparing a flexible stretchable stimulation electrode according to claim 9, characterized in that: The mass ratio of polydimethylsiloxane to curing agent is 15:1.

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