Mechanical interlocking epidermal electrode for collecting bio-electricity signals and preparation method of mechanical interlocking epidermal electrode

Abstract

The invention relates to the field of bioelectricity signal acquisition equipment, and discloses a mechanical interlocking epidermal electrode for bioelectricity signal acquisition and a preparation method, the mechanical interlocking epidermal electrode comprises a flexible polymer layer, a metal electrode layer and a hydrogel layer which are arranged in sequence, and the hydrogel layer is cured in situ on the metal electrode layer. The metal electrode layer and the in-situ cured hydrogel are mutually embedded to form a continuous seamless interface, so that the heterogeneous interface impedance is effectively reduced; the hydrogel layer has high conductivity, so that stable transmission of signals of the hydrogel layer can be ensured; the hydrogel layer has low Young modulus and high adhesion and can be matched with the modulus of the human skin, it is guaranteed that the epidermal electrode is stably attached to the human skin in a conformal mode for a long time, and meanwhile the requirement for collecting weak bio-electricity signals and the requirement for being tightly attached to the skin are met.

Description

Technical Field

[0001] This invention relates to the field of bioelectric signal acquisition equipment, and in particular to a mechanically interlocked epidermal electrode for bioelectric signal acquisition and its preparation method, mainly used for electromyography and electrocardiogram signal acquisition. Background Technology

[0002] Bioelectric signals are weak electrical activities generated by excitable tissues in the human body and recorded on the body surface. They include electrocardiogram (ECG), electromyography (EMG), and electroencephalogram (EEG), and reflect the real-time physiological state information of the human body.

[0003] Currently, bioelectrical signals have become an important source of information in clinical diagnosis and treatment: electrocardiogram (ECG) signals are the gold standard for identifying arrhythmias, myocardial infarction, and coronary artery disease; electromyography (EMG) signals can assist in assessing muscle function and neuromuscular diseases, serving rehabilitation training and sports performance analysis; and electroencephalogram (EEG) signals can be used for epilepsy monitoring and mental workload assessment. Taking atrial fibrillation, the most common and serious arrhythmia, as an example, with over 33 million patients worldwide, real-time ECG rhythm monitoring using epidermal electrodes can achieve real-time assessment of seizure load and recurrence trends, thereby reducing the risk of stroke and other embolic events and slowing disease progression.

[0004] Therefore, real-time acquisition of bioelectric signals plays an irreplaceable and important role in disease monitoring, risk warning, and rehabilitation assessment in the fields of cardiovascular, nervous and musculoskeletal systems, which puts forward higher requirements for epidermal electrodes: they need to have high conductivity, interface stability and wearing comfort in order to achieve high-fidelity acquisition of bioelectric signals.

[0005] Commonly used epidermal electrodes can be categorized into three types: metal electrodes, conductive polymer electrodes, and composite electrodes. Metal electrodes offer excellent conductivity and can be designed with stretchable structures such as meshes, snake-like shapes, and paper cutouts to enhance their flexibility and adapt to skin deformation. However, the difference in modulus between metals (modulus > 10 GPa) and human skin (modulus approximately 0.6-4.5 MPa) can easily lead to interfacial mismatch, resulting in instability phenomena such as cracking and delamination during long-term bioelectrical signal acquisition, thus causing signal distortion. In contrast, conductive polymer electrodes (such as hydrogels, commonly used in commercial electrodes) have extremely low modulus (0.1-200 kPa), allowing for close adhesion to the skin and improved comfort. Although the electrical properties of hydrogels can be improved to some extent by incorporating multiple conductive components, their achievable conductivity is still far lower than that of metal electrodes, making it difficult to meet the needs of acquiring weak bioelectrical signals. Composite electrodes combine the high conductivity of metal electrodes with the low modulus of conductive polymers, making them suitable for acquiring weak bioelectrical signals. However, due to weak interfacial adhesion, they are prone to detachment, leading to acquisition failure. Summary of the Invention

[0006] The main objective of this invention is to provide a mechanically interlocked epidermal electrode for bioelectric signal acquisition and its preparation method, aiming to solve the problem that existing epidermal electrodes cannot simultaneously achieve close skin contact and efficient acquisition of weak bioelectric signals.

[0007] To achieve the above objectives, the present invention proposes a mechanically interlocked epidermal electrode for bioelectric signal acquisition, comprising a flexible polymer layer, a metal electrode layer and a hydrogel layer arranged sequentially, wherein the hydrogel layer is cured in situ on the metal electrode layer.

[0008] Preferably, the flexible polymer is at least one of polyimide, polydimethylsiloxane, polyurethane, and hydrogenated styrene-ethylene / butene-styrene block copolymer.

[0009] Preferably, the metal electrode layer includes metal wires, which are arranged in at least one of a random network or a matrix; the width of the metal wires is 40 micrometers to 300 micrometers; and the thickness of the metal wires is 20 nanometers to 4 micrometers.

[0010] Preferably, the metal electrode layer is at least one of a gold electrode layer, a silver electrode layer, and a copper electrode layer.

[0011] Preferably, the hydrogel layer comprises, by weight percentage, 10% to 60% acryloylmorpholine; 0.1% to 0.6% crosslinking agent; 0.2% to 1.2% photoinitiator; 17% to 63% deionized water; and 10% to 37% sodium acrylate.

[0012] Preferably, the crosslinking agent is at least one of polyethylene glycol acrylate, polyethylene glycol dimethacrylate, and N,N-methylenebisacrylamide.

[0013] Preferably, the photoinitiator is diphenyl(2,4,6) Trimethylbenzoyl)phosphine oxide, 2,4,6 Ethyl trimethylbenzoylphenylphosphonate, phenylbis(2,4,6) Trimethylbenzoyl)phosphine oxide, phenyl(2,4,6) Lithium trimethylbenzoyl phosphate, 2 Isopropyl thioxanthone, 2,4 Diethylthiazolidinone, 2 Ethylanthraquinone, tetraethylmistezone and bis(2,6) Difluoride 3 At least one of pyrrolidinium-based titanium dioxide.

[0014] To achieve the above objectives, this invention proposes a method for preparing a mechanically interlocked epidermal electrode for bioelectrical signal acquisition, which utilizes any of the aforementioned mechanically interlocked epidermal electrodes for bioelectrical signal acquisition, comprising: A flexible polymer solution is spin-coated onto the surface of a hard wafer substrate, and then the flexible polymer solution is thermally cured to obtain a flexible polymer layer. A photoresist precursor solution is spin-coated onto the side of the flexible polymer layer away from the hard wafer substrate, and then the photoresist precursor solution is annealed to obtain a photoresist film. The side of the photoresist film away from the flexible polymer layer is exposed and developed, and then the side of the photoresist film away from the flexible polymer layer is rinsed with deionized water and dried with nitrogen to obtain a preset photoresist electrode pattern. Metallize one side of the photoresist film that forms the photoresist electrode pattern, and form a metal electrode layer on the photoresist electrode pattern; The photoresist film is removed by mechanical peeling; The hydrogel precursor solution was coated onto the metal electrode layer; The hydrogel precursor solution is photocured in situ to form a hydrogel layer, thereby creating an interlocking interface between the hydrogel layer and the metal electrode layer.

[0015] Preferably, the method for preparing the hydrogel precursor solution includes: Acryloylmorpholine, crosslinking agent and photoinitiator were obtained in a first preset mass, and mixed and stirred at room temperature for 10 to 30 minutes. The mixture was then allowed to stand and defoam to form a first solution. Obtain a second preset mass of sodium acrylate and add it to deionized water. After it is fully dissolved, stir it at room temperature for 10 to 30 minutes to fully dissolve the sodium acrylate. Then let it stand to defoam and form a second solution. The first solution and the second solution are mixed and stirred for 10 to 20 minutes to obtain a mixed solution; the mixed solution is then vacuumed in a dark environment to remove air bubbles, resulting in a homogeneous hydrogel precursor solution.

[0016] Preferably, the in-situ photocuring of the hydrogel precursor solution to form a hydrogel layer comprises: irradiating the hydrogel precursor solution with ultraviolet light of wavelength 365 nm and power 6 watts for 4 to 6 seconds to obtain the in-situ cured hydrogel layer. Compared with the prior art, the present invention has at least the following beneficial effects: The continuous, seamless interface formed by the interlocking of the metal electrode layer and the in-situ cured hydrogel allows for mechanical interlocking, effectively reducing the heterogeneous interface impedance. The hydrogel layer possesses high conductivity, ensuring stable signal transmission. Furthermore, the hydrogel layer exhibits low Young's modulus and high adhesion, matching the modulus of human skin to guarantee long-term stable conformal adhesion of the epidermal electrode to the skin, while simultaneously meeting the requirements for acquiring weak bioelectrical signals. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a mechanically interlocked epidermal electrode for bioelectric signal acquisition according to the present invention; Figure 2 This is a schematic flowchart of an embodiment of a method for preparing a mechanically interlocked epidermal electrode for bioelectric signal acquisition according to the present invention; Figure 3 The conductivity diagrams are for the hydrogels in Examples 1 to 3. Figure 4 This is a stress-strain curve of the hydrogel in Example 1; Figure 5 This is a graph showing the adhesion strength of the hydrogel in Example 1; Figure 6 The images show the SEM micrograph and EDS energy dispersive spectroscopy of the mechanical interlocking interface of the epidermal electrode in Example 1. Figure 7 This is an adhesion strength diagram of the mechanical interlocking interface of the epidermal electrodes in Example 1; Figure 8 This is a long-term impedance diagram of the epidermal electrode in Example 1; Figure 9 This is an impedance comparison diagram of the epidermal electrode in Example 1; Figure 10 Figure a shows the impedance comparison of the epidermal electrode in Example 1 under sweat conditions.

[0019] Figure 11 Figure b shows the impedance comparison of the epidermal electrode in sweat environment in Example 1.

[0020] Figure 12 Figure c shows the impedance comparison of the epidermal electrode in Example 1 under high humidity conditions; Figure 13Figure d shows the impedance comparison of the epidermal electrode in Example 1 under high humidity conditions; Figure 14 Figure e shows the impedance comparison of the epidermal electrode in Example 1 under high temperature conditions; Figure 15 Figure f shows the impedance comparison of the epidermal electrode in Example 1 under high temperature conditions; Figure 16 This is a comparison chart of electromyography signals collected by the epidermal electrode in Example 1 with those of commercial Ag / AgCl electrodes, metal electrodes, and their sensitivity. Figure 17 This is a graph showing the electrocardiogram signals (for a total of five days) collected stably over a long period using the epidermal electrodes in Example 1. Figure 18 Electromyography (EMG) signals from elderly patients with respiratory diseases and post-kidney transplant patients were clinically collected using the epidermal electrodes in Example 1. Figure 19 The image shows the electrocardiogram of atrial fibrillation patients clinically acquired using the epidermal electrode in Example 1. Figure 20 This is a simplified finished product diagram for step S20; Figure 21 A simplified finished product diagram for step S30; Figure 22 A simplified finished product diagram of the metallization process in step S40; Figure 23 This is a simplified finished product diagram of the metal electrode layer formed in step S40; Figure 24 A simplified finished product diagram for step S50; Figure 25 A simplified finished product diagram for step S60; Figure 26 This is a simplified finished product diagram of step S70 (i.e., mechanically interlocked skin electrode). Explanation of icon numbers: 1- Rigid wafer substrate; 2- Flexible polymer layer; 3- Photoresist film; 4- Metal electrode layer; 5- Hydrogel precursor solution; 6- Hydrogel layer; The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0022] The following description, with reference to the accompanying drawings, illustrates an embodiment of the present invention of a mechanically interlocked epidermal electrode for bioelectric signal acquisition and its preparation method.

[0023] See Figure 2 A mechanically interlocked epidermal electrode for bioelectric signal acquisition includes a flexible polymer layer 2, a metal electrode layer 4, and a hydrogel layer 6 sequentially disposed thereon, wherein the hydrogel layer 6 is cured in situ on the metal electrode layer 4. The flexible polymer is at least one of polyimide, polydimethylsiloxane, polyurethane, and hydrogenated styrene-ethylene / butene-styrene block copolymer. The flexible polymer layer 2 provides overall flexible support.

[0024] The metal electrode layer comprises metal wires arranged in at least one of the following patterns: a random network or a matrix. The width of the metal wires ranges from 40 micrometers to 300 micrometers, and the thickness ranges from 20 nanometers to 4 micrometers. The metal wires form stretchable metal electrode patterns such as serpentine arrays, circular hole arrays, polygonal arrays, paper-cut structures, or random grids. These stretchable metal electrode patterns disperse strain and prevent metal fracture. The acryloylmorpholine-sodium acrylate hydrogel, under the combined effect of low cross-linking degree and high water content, exhibits a low Young's modulus, matching the modulus of skin in the range of 10 kPa to 100 kPa, significantly reducing interfacial stress concentration and contact resistance fluctuations caused by surface movement, bending, and stretching.

[0025] Meanwhile, the numerous hydrophilic groups in the hydrogel can form hydrogen bonds and other adhesion mechanisms with skin surface proteins, enabling the epidermal electrodes to adhere stably and conformally for a long time without the use of additional adhesives, thus improving wearing comfort and reducing the risk of skin irritation.

[0026] The metal electrode layer is at least one of a gold electrode layer, a silver electrode layer, and a copper electrode layer.

[0027] The hydrogel layer 6 comprises, by weight percentage: 10% to 60% acryloylmorpholine; 0.1% to 0.6% crosslinking agent; 0.2% to 1.2% photoinitiator; 17% to 63% deionized water; and 10% to 37% sodium acrylate. Through the combination of a "continuous interlocking structure + highly conductive material system + in-situ curing process," the "air gaps" and local voids that easily occur in traditional bonding methods are eliminated, creating a continuous and seamless charge transport path between the gold, silver, or copper metal electrodes and the sodium acrylate-containing polyelectrolyte hydrogel. In-situ curing not only ensures close contact but also promotes multiple interactions between the hydrogel segments and the metal surface, including hydrogen bonds, van der Waals forces, and metal-OH coordination bonds, further stabilizing the interfacial microstructure and reducing interfacial impedance from both structural and interfacial chemical perspectives. Based on this coupled design of "material system + interlocking structure + process," the epidermal electrode maintains low impedance and low noise output even in complex environments such as sweat, high humidity, and high temperature, demonstrating excellent environmental adaptability and signal stability.

[0028] The hydrogel layer 6 constructs a three-dimensional polyelectrolyte network with high water content and high ion mobility, which works synergistically with the high-conductivity metal electrode pattern to achieve a composite conductive path of "ion conduction + electronic conduction". Combined with the low contact impedance provided by the mechanically interlocked interface, this invention can significantly reduce signal attenuation and thermal noise during bioelectrical signal acquisition, improve the signal-to-noise ratio of ECG, EMG, EEG, EEG, and EKG signals, thereby achieving stable, continuous, and high-fidelity bioelectrical signal transmission. The crosslinking agent is at least one of polyethylene glycol acrylate, polyethylene glycol dimethacrylate, and N,N-methylenebisacrylamide.

[0029] The photoinitiator is diphenyl(2,4,6) Trimethylbenzoyl)phosphine oxide, 2,4,6 Ethyl trimethylbenzoylphenylphosphonate, phenylbis(2,4,6) Trimethylbenzoyl)phosphine oxide, phenyl(2,4,6) Lithium trimethylbenzoyl phosphate, 2 Isopropyl thioxanthone, 2,4 Diethylthiazolidinone, 2 Ethylanthraquinone, tetraethylmistezone and bis(2,6) Difluoride 3 At least one of pyrrolidinium-based titanium dioxide.

[0030] See Figure 1 A method for preparing a mechanically interlocked epidermal electrode for bioelectrical signal acquisition, comprising using any one of the aforementioned mechanically interlocked epidermal electrodes for bioelectrical signal acquisition, including: Step S10: Spin-coat a flexible polymer solution onto the surface of the hard wafer substrate 1, and then heat-cur the flexible polymer solution to obtain a flexible polymer layer 2. Step S20: Spin-coat the side of the flexible polymer layer 2 away from the hard wafer substrate 1 with a photoresist precursor solution, and then anneal the photoresist precursor solution to obtain the photoresist film 3; see [link to previous step]. Figure 20 ; Step S30: Expose and develop the side of the photoresist film 3 facing away from the flexible polymer layer 2, then rinse the side of the photoresist film 3 facing away from the flexible polymer layer 2 with deionized water and dry it with nitrogen gas to obtain the preset photoresist electrode pattern; see [link to relevant documentation]. Figure 21 ; Step S40: Metallize the side of the photoresist film 3 where the photoresist electrode pattern is formed, and form a metal electrode layer 4 on the photoresist electrode pattern; see [link to previous step]. Figure 22 and Figure 23 ; Step S50: The photoresist film 3 is removed by mechanical peeling; see [link to relevant documentation]. Figure 24 ; Step S60: Coat the hydrogel precursor solution 5 onto the metal electrode layer 4; see [link to previous step]. Figure 25 ; Step S70: The in-situ photocurable hydrogel precursor solution 5 forms a hydrogel layer 6, creating an interlocking interface between the hydrogel layer 6 and the metal electrode layer 4. See also... Figure 26 ; Stretchable metal electrode patterns, such as serpentine arrays, circular hole arrays, polygonal arrays, paper-cut structures, or random grids, are prepared on flexible polyimide substrates using semiconductor processes. Acryloylmorpholine-sodium acrylate hydrogel precursor solution is then introduced onto these patterns via spin coating and in-situ UV curing.

[0031] By utilizing the high fluidity of the precursor solution in its liquid state and the slight volume shrinkage during the curing process, the hydrogel fully penetrates and encapsulates the uneven structure of the metal pattern, ultimately forming a three-dimensionally interlocked interface between the hydrogel network and the metal microstructure. Compared to traditional planar bonding interfaces, this interlocked interface, constructed through a combination of structure and process, significantly improves the heterogeneous interface adhesion strength between the hydrogel layer 6 and the metal electrode layer 4. This effectively prevents interface peeling caused by sweat wetting, mechanical disturbance, or temperature fluctuations during long-term use, thus ensuring the long-term reliability of the heterogeneous interface of the epidermal electrode.

[0032] Specifically, the hard wafer substrate 1 is at least one of silicon and silicon dioxide; the photoresist precursor solution is at least one of optical i-line positive photoresist and optical i-line negative photoresist; the spin coating speed of the photoresist precursor solution is 2000 rpm to 8000 rpm; the annealing temperature of the photoresist precursor solution is 60°C to 300°C, and the annealing time is 1 minute to 5 minutes; the exposure method of the photoresist film 3 is at least one of contact mask exposure, proximity mask exposure, projection mask exposure, and laser direct writing exposure; the developer used for developing the photoresist film 3 is at least one of inorganic developer and organic developer; and the metallization method is at least one of physical vapor deposition and chemical vapor deposition.

[0033] The preparation method of hydrogel precursor solution 5 includes: Step S80: Obtain a first preset mass of acryloylmorpholine, crosslinking agent and photoinitiator respectively, mix and stir at room temperature for 10 to 30 minutes, let stand to defoam, and form a first solution; Step S81: Obtain a second preset mass of sodium acrylate and add it to deionized water. After it is fully dissolved, stir it at room temperature for 10 to 30 minutes to fully dissolve the sodium acrylate and let it stand to defoam, forming a second solution. Step S82: Mix the first solution and the second solution and stir for 10 to 20 minutes to obtain a mixed solution; vacuum the mixed solution in a dark environment to remove bubbles and obtain a uniform hydrogel precursor solution 5.

[0034] The in-situ photocurable hydrogel precursor solution 5 forms a hydrogel layer 6 by irradiating the hydrogel precursor solution with ultraviolet light of wavelength 365 nm and power of 6 watts for 4 to 6 seconds to obtain an in-situ cured hydrogel layer 6. The hydrogel layer 6 has low modulus (14.8 kPa), high elongation (415%) and tissue adhesion, so that the metal electrode layer 4 can adhere to human skin.

[0035] Thanks to the overall synergistic design of the aforementioned material system, interface structure, and preparation process, the epidermal electrode of this invention possesses long-term stable adhesion, low interfacial impedance, high signal-to-noise ratio, and excellent environmental adaptability in the acquisition of multimodal bioelectrical signals (including ECG, EMG, EEG, EOG, and electrodermal signals). It can achieve accurate monitoring of bioelectrical signals, which is significantly superior to traditional dry electrodes or simple adhesive hydrogel electrodes, fully demonstrating the broad application prospects of this invention in clinical monitoring, rehabilitation assessment, and wearable health monitoring devices.

[0036] Example 1: A mechanically interlocked epidermal electrode for bioelectric signal acquisition, wherein the flexible polymer is made of polyimide; the metal electrode layer 4 is arranged in a serpentine array; the width of the metal wires in the metal electrode layer 4 is 200 μm and the thickness is 200 nm; the metal electrode layer 4 is a silver electrode layer.

[0037] The hydrogel layer 6 comprises, by weight percentage, 20% acrylomorpholine, 0.1% crosslinking agent, 0.2% photoinitiator, 50% deionized water, and 30% sodium acrylate.

[0038] The crosslinking agent is polyethylene glycol acrylate; the photoinitiator is diphenyl (2,4,6-diphenyl acrylate). (Trimethylbenzoyl)phosphine oxide.

[0039] Acryloylmorpholine, crosslinking agent and photoinitiator were obtained in a first preset mass, mixed and stirred at room temperature for 30 minutes, and allowed to stand to defoam, forming a first solution; Obtain a second preset mass of sodium acrylate and add it to deionized water. After it is fully dissolved, stir it at room temperature for 30 minutes to fully dissolve the sodium acrylate and then let it stand to defoam, forming a second solution. The first solution and the second solution were mixed and stirred for 20 minutes to obtain a mixed solution; the mixed solution was then vacuumed in a dark environment to remove air bubbles, resulting in a uniform hydrogel precursor solution 5; The hydrogel precursor solution was irradiated with ultraviolet light at a wavelength of 365 nm and a power of 6 watts for 6 seconds to obtain the hydrogel layer 6 that was cured in situ.

[0040] Based on the above-mentioned method for fabricating a mechanically interlocked epidermal electrode for bioelectric signal acquisition, the adjusted parameters include: the hard wafer substrate 1 is silicon; the photoresist precursor solution is an optical i-line positive photoresist; the spin coating speed of the photoresist precursor solution is 5000 rpm; the annealing temperature of the photoresist precursor solution is 105℃, and the annealing time is 2 minutes; the exposure method of the photoresist film 3 is contact mask exposure; the developing solution used for developing the photoresist film 3 is an inorganic developing solution; and the metallization method is physical vapor deposition.

[0041] The aforementioned epidermal electrodes can be used to collect electromyographic signals from elderly patients with diseases, kidney transplant patients, and electrocardiographic signals from patients with atrial fibrillation.

[0042] See Figures 1 to 19 , Figures 1 to 19 All experiments and results were conducted using the mechanically interpenetrated electrode prepared in Example 1.

[0043] Example 2: A mechanically interlocked epidermal electrode for bioelectric signal acquisition, wherein the flexible polymer material is polydimethylsiloxane; the metal electrode layer 4 has a paper-cut structure; the width of the metal wire in the metal electrode layer 4 is 50 μm and the thickness is 50 nm; the metal electrode layer 4 is a gold material electrode layer.

[0044] The hydrogel layer 6 comprises, by weight percentage, 20% acrylomorpholine, 0.15% crosslinking agent, 0.3% photoinitiator, 60% deionized water, and 20% sodium acrylate.

[0045] The crosslinking agent is polyethylene glycol dimethacrylate; the photoinitiator is 2,4,6 Ethyl trimethylbenzoylphenylphosphonate.

[0046] Acryloylmorpholine, crosslinking agent and photoinitiator were obtained in a first preset mass, mixed and stirred at room temperature for 10 minutes and allowed to stand to defoam, forming a first solution; Obtain a second preset mass of sodium acrylate and add it to deionized water. After it is fully dissolved, stir it at room temperature for 10 minutes to fully dissolve the sodium acrylate and then let it stand to defoam, forming a second solution. The first solution and the second solution were mixed and stirred for 10 minutes to obtain a mixed solution; the mixed solution was then vacuumed in a dark environment to remove air bubbles, resulting in a uniform hydrogel precursor solution 5; The hydrogel precursor solution was irradiated with ultraviolet light at a wavelength of 365 nm and a power of 6 watts for 4 seconds to obtain the hydrogel layer 6 that was cured in situ.

[0047] Based on the above-mentioned method for fabricating a mechanically interlocked epidermal electrode for bioelectric signal acquisition, the adjusted parameters include: the hard wafer substrate 1 is silicon dioxide; the photoresist precursor solution is an optical i-line negative photoresist; the spin coating speed of the photoresist precursor solution is 3000 rpm; the annealing temperature of the photoresist precursor solution is 95°C, and the annealing time is 3 minutes; the exposure method of the photoresist film 3 is proximity mask exposure; the developing solution used for developing the photoresist film 3 is an organic developing solution; and the metallization method is physical vapor deposition.

[0048] Example 3: A mechanically interlocked epidermal electrode for bioelectric signal acquisition, wherein the flexible polymer is made of polyimide; the metal electrode layer 4 is in the form of a random grid; the width of the metal wires in the metal electrode layer 4 is 100 μm and the thickness is 500 nm; the metal electrode layer 4 is a silver electrode layer.

[0049] The hydrogel layer 6 comprises, by weight percentage, 20% acrylomorpholine, 0.2% crosslinking agent, 0.4% photoinitiator, 55% deionized water, and 25% sodium acrylate.

[0050] The crosslinking agent is polyethylene glycol acrylate; the photoinitiator is phenylbis(2,4,6)-methyl-2,4,6-ethylhexylene ...ethylhexylene(2,4,6)-ethylhexylene(2,4,6)-ethylhexylene(2,4, (Trimethylbenzoyl)phosphine oxide.

[0051] Acryloylmorpholine, crosslinking agent and photoinitiator were obtained in a first preset mass, mixed and stirred at room temperature for 20 minutes, and allowed to stand to defoam, forming a first solution; Obtain a second preset mass of sodium acrylate and add it to deionized water. After it is fully dissolved, stir it at room temperature for 20 minutes to fully dissolve the sodium acrylate and then let it stand to defoam, forming a second solution. The first solution and the second solution were mixed and stirred for 15 minutes to obtain a mixed solution; the mixed solution was then vacuumed in a dark environment to remove air bubbles, resulting in a uniform hydrogel precursor solution 5. The hydrogel precursor solution was irradiated with ultraviolet light at a wavelength of 365 nm and a power of 6 watts for 5 seconds to obtain the hydrogel layer 6 that was cured in situ.

[0052] Based on the above-mentioned method for fabricating a mechanically interlocked epidermal electrode for bioelectric signal acquisition, the adjusted parameters include: the hard wafer substrate 1 is silicon; the photoresist precursor solution is an optical i-line positive photoresist; the spin coating speed of the photoresist precursor solution is 5000 rpm; the annealing temperature of the photoresist precursor solution is 100℃, and the annealing time is 1 minute; the exposure method of the photoresist film 3 is laser direct writing exposure; the developing solution used for developing the photoresist film 3 is an inorganic developing solution; and the metallization method is physical vapor deposition.

[0053] In the description of this specification, references are made to the terms "one embodiment", "another embodiment", "other embodiments" Descriptions such as "example" or "first embodiment to Xth embodiment" refer to descriptions in conjunction with that embodiment or example. Specific features, structures, materials, or characteristics are included in at least one embodiment or example of the present invention.

[0054] In this specification, the illustrative expressions of the terms used above do not necessarily refer to the same embodiments or examples.

[0055] Furthermore, the specific features, structures, materials, method steps, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0056] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to... This encompasses non-exclusivity inclusion, thereby allowing a process, method, article, or device to include a range of elements. The setting includes not only those elements, but also other elements not explicitly listed, or may also include... Elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0057] The sequence numbers of the above embodiments of the present invention are merely for descriptive purposes and do not represent the superiority or inferiority of the embodiments. Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases, the former is a better implementation method. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0058] The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited thereto. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art, guided by the teachings of this invention, will apply the principles and claims of this invention without departing from its spirit and scope. Within the scope of protection, many other forms can be made, all of which fall within the protection scope of this invention.

Claims

1. A mechanically interlocked epidermal electrode for bioelectrical signal acquisition, characterized in that, It includes a flexible polymer layer, a metal electrode layer and a hydrogel layer arranged in sequence, wherein the hydrogel layer is cured in situ on the metal electrode layer.

2. The mechanically interlocked epidermal electrode for bioelectrical signal acquisition as described in claim 1, characterized in that, The flexible polymer is at least one of polyimide, polydimethylsiloxane, polyurethane, and hydrogenated styrene-ethylene / butene-styrene block copolymer.

3. The mechanically interlocked epidermal electrode for bioelectrical signal acquisition as described in claim 1, characterized in that, The metal electrode layer includes metal wires, which are arranged in at least one of a random network or a matrix; the width of the metal wires is from 40 micrometers to 300 micrometers; and the thickness of the metal wires is from 20 nanometers to 4 micrometers.

4. The mechanically interlocked epidermal electrode for bioelectrical signal acquisition as described in claim 1, characterized in that, The metal electrode layer is at least one of a gold electrode layer, a silver electrode layer, and a copper electrode layer.

5. A mechanically interlocked epidermal electrode for bioelectrical signal acquisition as described in any one of claims 1-4, characterized in that, The hydrogel layer comprises, by weight percentage, 10% to 60% acryloylmorpholine; 0.1% to 0.6% crosslinking agent; 0.2% to 1.2% photoinitiator; 17% to 63% deionized water; and 10% to 37% sodium acrylate.

6. A mechanically interlocked epidermal electrode for bioelectrical signal acquisition as described in claim 5, characterized in that, The crosslinking agent is at least one of polyethylene glycol acrylate, polyethylene glycol dimethacrylate, and N,N-methylenebisacrylamide.

7. A mechanically interlocked epidermal electrode for bioelectrical signal acquisition as described in claim 5, characterized in that, The photoinitiator is diphenyl(2,4,6) Trimethylbenzoyl)phosphine oxide, 2,4,6 Ethyl trimethylbenzoylphenylphosphonate, phenylbis(2,4,6) Trimethylbenzoyl)phosphine oxide, phenyl(2,4,6) Lithium trimethylbenzoyl phosphate, 2 Isopropyl thioxanthone, 2,4 Diethylthiazolidinone, 2 Ethylanthraquinone, tetraethylmistezone and bis(2,6) Difluoride 3 At least one of pyrrolidinium-based titanium dioxide.

8. A method for preparing a mechanically interlocked epidermal electrode for bioelectrical signal acquisition, comprising the mechanically interlocked epidermal electrode for bioelectrical signal acquisition as described in any one of claims 1-7, characterized in that, include: A flexible polymer solution is spin-coated onto the surface of a hard wafer substrate, and then the flexible polymer solution is thermally cured to obtain a flexible polymer layer. A photoresist precursor solution is spin-coated onto the side of the flexible polymer layer away from the hard wafer substrate, and then the photoresist precursor solution is annealed to obtain a photoresist film. The side of the photoresist film away from the flexible polymer layer is exposed and developed, and then the side of the photoresist film away from the flexible polymer layer is rinsed with deionized water and dried with nitrogen to obtain a preset photoresist electrode pattern. Metallize one side of the photoresist film that forms the photoresist electrode pattern, and form a metal electrode layer on the photoresist electrode pattern; The photoresist film was removed by mechanical peeling; The hydrogel precursor solution was coated onto the metal electrode layer; The hydrogel precursor solution is photocured in situ to form a hydrogel layer, thereby creating an interlocking interface between the hydrogel layer and the metal electrode layer.

9. A method for preparing a mechanically interlocked epidermal electrode for bioelectrical signal acquisition as described in claim 8, characterized in that, The method for preparing the hydrogel precursor solution includes: Acryloylmorpholine, crosslinking agent and photoinitiator were obtained in a first preset mass, and mixed and stirred at room temperature for 10 to 30 minutes. The mixture was then allowed to stand and defoam to form a first solution. Obtain a second preset mass of sodium acrylate and add it to deionized water. After it is fully dissolved, stir it at room temperature for 10 to 30 minutes to fully dissolve the sodium acrylate. Then let it stand to defoam and form a second solution. The first solution and the second solution are mixed and stirred for 10 to 20 minutes to obtain a mixed solution; the mixed solution is then vacuumed in a dark environment to remove air bubbles, resulting in a homogeneous hydrogel precursor solution.

10. A method for preparing a mechanically interlocked epidermal electrode for bioelectrical signal acquisition as described in claim 8, characterized in that, The in-situ photocuring of the hydrogel precursor solution to form a hydrogel layer includes: irradiating the hydrogel precursor solution with ultraviolet light of wavelength 365 nm and power of 6 watts for 4 to 6 seconds to obtain the in-situ cured hydrogel layer.

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