Electrophysiological signal acquisition device and system with motion artifact perception function

Abstract

The application discloses an electrophysiological signal acquisition device and system with motion artifact perception function, which comprises a flexible base layer; an electrode layer arranged on the base layer, which comprises patterned first, second and third conductive electrodes; a composite perception layer arranged on the surface of the electrode layer, which comprises first, second and third microstructure arrays arranged in a coplanar staggered manner, and the original signal acquisition units, the ionically perceived positive subunit units and the ionically perceived negative subunit units constituting each microstructure array are all microstructures made of ionic gel materials, and adjacent microstructures are spaced from each other and electrically insulated; based on the above structure, an electrophysiological signal acquisition channel and an ionically perceived channel are formed, which are respectively used for acquiring mixed signals containing electrophysiological signals and motion artifacts and for acquiring compensation signals for representing the capacitance change of the contact interface between the composite perception layer and the skin; wherein the compensation signals are used for eliminating the motion artifacts in the mixed signals, so as to extract the electrophysiological signals.

Description

Technical Field

[0001] This invention belongs to the field of electrophysiological signal acquisition, specifically relating to an electrophysiological signal acquisition device and system with motion artifact sensing function. Background Technology

[0002] Physiological signals reflect the health status of the human body, and their collection and monitoring are of great significance in disease prevention, clinical diagnosis, and health management. Among common physiological signal types, electrophysiological signals are highly representative. Electrophysiological signals can reflect the electrical activity state of the human heart, muscles, and nervous system. Among them, electrocardiogram (ECG), electromyography (EMG), and electrooculogram (EOG) are typical electrophysiological signal types, and they have irreplaceable application value in clinical medicine and biomedical engineering. Taking electrocardiogram (ECG) as an example, its waveform can characterize the electrical activity process of the heart during a cardiac cycle, and it can be used to identify various arrhythmias and cardiovascular diseases, making it one of the most representative electrophysiological signals in clinical diagnosis and health monitoring.

[0003] With the development of flexible electronics technology, wearable medical devices have gradually become important tools for health monitoring. In recent years, portable electrophysiological signal acquisition devices such as smart bracelets, electrocardiographs, and blood pressure monitors have emerged, enabling real-time, non-invasive physiological signal acquisition and analysis. These devices are used to monitor parameters such as heart rate, blood oxygen, and respiratory rate, and to track the progression of chronic diseases such as diabetes and hypertension. However, in practical applications, existing electrophysiological signal acquisition devices generally suffer from unstable signal quality in dynamic environments. Everyday behaviors such as exercise, breathing, and sweating can cause displacement or deformation of the skin surface, leading to instability of the electrophysiological signal acquisition interface, i.e., interface state perturbation. This results in the acquired raw signals carrying varying degrees of motion artifacts, such as baseline drift and waveform distortion, which seriously affects the accurate acquisition and analysis of electrophysiological signals.

[0004] Artifact interference is generally classified into two categories: passive interference caused by interface mismatch, such as mismatch between electrode and skin modulus leading to poor adhesion, poor contact, or slippage and partial detachment during use; and active interference caused by external dynamics, such as mechanical disturbances like limb movement, skin stretching, or chest rise directly affecting the electrode-skin interface. Because the electrophysiological signal itself has a low amplitude, the amplitude of these artifacts is often much higher than the original signal, easily masking key waveform features. Existing motion artifact suppression strategies are mainly divided into passive and active categories. Passive methods primarily improve interface stability by optimizing electrode material performance and structural design, for example, by improving the material's conductivity, flexibility, and skin adhesion, thereby reducing signal fluctuations caused by motion. Active methods rely on external sensors and algorithmic compensation mechanisms, such as using rigid devices like inertial measurement units (IMUs) or accelerometers to acquire motion information, and then using signal separation, filtering, or modeling algorithms for artifact compensation and correction. However, these strategies still have significant limitations in complex dynamic environments: passive methods are difficult to cope with interface instability caused by motion, that is, they cannot eliminate motion artifacts; active methods can usually only capture overall motion information and cannot coordinate with the deformation of the skin interface, making it difficult to accurately reflect the true dynamic state of the skin interface. Consequently, it is also difficult to accurately collect electrophysiological signals on the skin surface in dynamic environments.

[0005] In summary, existing electrophysiological signal acquisition schemes are insufficient in terms of electrode material stability and dynamic anti-interference capabilities, making it difficult to achieve high-quality acquisition of raw electrophysiological signals in wearable and continuous monitoring scenarios. Summary of the Invention

[0006] This invention provides an electrophysiological signal acquisition device with motion artifact detection capability. Based on a coplanar composite sensing structure designed with ionogel material, it can continuously monitor raw electrophysiological signals while simultaneously sensing the perturbation at the interface between the ionogel material and the skin, outputting a compensation signal for eliminating motion artifacts in the raw electrophysiological signals. Furthermore, this invention also provides a system including the aforementioned electrophysiological signal acquisition device with motion artifact detection capability.

[0007] The first aspect of this invention discloses an electrophysiological signal acquisition device with motion artifact detection function, comprising:

[0008] Flexible substrate layer;

[0009] An electrode layer disposed on a substrate layer, the electrode layer comprising a patterned first conductive electrode, a second conductive electrode and a third conductive electrode;

[0010] A composite sensing layer is arranged on the surface of the electrode layer. The composite sensing layer includes a first microstructure array, a second microstructure array, and a third microstructure array arranged in a coplanar staggered manner. The original signal acquisition unit constituting the first microstructure array, the ionization sensing positive electrode unit constituting the second microstructure array, and the ionization sensing negative electrode unit constituting the third microstructure array are all microstructures made of ion gel material, and adjacent microstructures are spaced apart from each other and electrically insulated.

[0011] The original signal acquisition unit is connected to the first conductive electrode to form an electrophysiological signal acquisition channel, which is used to acquire a mixed signal containing electrophysiological signals and motion artifacts.

[0012] The positive and negative ionization sensing sub-units are used in pairs and are respectively connected to the second and third conductive electrodes to form an ionization sensing channel, which is used to detect and output a compensation signal characterizing the capacitance change at the interface between the composite sensing layer and the skin; wherein, the compensation signal is used to eliminate motion artifacts in the mixed signal in order to extract the electrophysiological signal.

[0013] As an alternative, in the composite sensing layer, a raw signal acquisition unit is adjacent to at least one pair of ion-sensing positive and ion-sensing negative sub-units.

[0014] As an alternative, all microstructures in the composite sensing layer have the same or substantially the same geometry and dimensions.

[0015] As an alternative, the material used to prepare the original signal acquisition unit has stretchable self-adhesive properties; the material used to prepare the positive and negative ion sensing poles has lower adhesion than the ion gel material used to prepare the original signal acquisition unit, but stronger mechanical properties.

[0016] As an alternative, the electrophysiological signal acquisition unit is prepared based on a PAAc-DES ion gel precursor solution; the ionization sensing positive electrode unit and the ionization sensing negative electrode unit are prepared based on a precursor solution obtained by mixing the PAAc-DES ion gel precursor solution and fumed silica.

[0017] As an optional embodiment, the PAAc-DES ionogel precursor solution is obtained by mixing a deep eutectic solvent, acrylic acid, initiator, and crosslinking agent in mass percentages of 27.9%~29.9%, 69%~71%, 0.9%~1.1%, and 0.09%~0.11%, respectively; in the deep eutectic solvent, the molar ratio of choline chloride to hydrogen bond donor ethylene glycol is 1:1.9~2.1.

[0018] In the preparation of the precursor solutions for the ionization sensing positive and negative electrode units, the mass ratio of the PAAc-DES ion gel precursor solution to fumed silica is 9.5~10.5:1.

[0019] As an alternative, the first conductive electrode, the second conductive electrode, and the third conductive electrode are all made of silver paste or PEDOT:PSS conductive polymer.

[0020] As an alternative, the composite sensing layer further includes a fourth microstructure array arranged coplanarly and interleaved with the first, second, and third microstructure arrays; the damping unit constituting the fourth microstructure array is a microstructure based on an ion gel material; the ion gel material used to prepare the damping unit has a network structure that combines viscoelasticity and energy dissipation characteristics.

[0021] As an alternative, in the composite sensing layer, the smallest repeating unit in the overall microstructure array formed by the first microstructure array, the second microstructure array, the third microstructure array and the fourth microstructure array includes an original signal acquisition unit, a damping unit, and a pair of adjacent ionization sensing positive and ionization sensing negative units.

[0022] As an alternative, in the composite sensing layer, the overall microstructure array formed by the first microstructure array, the second microstructure array, the third microstructure array and the fourth microstructure array is a hexagonal lattice, a square lattice, a rectangular lattice or an oblique lattice structure.

[0023] As an alternative, the precursor solution for preparing the damping unit is prepared by mixing a deep eutectic solvent (DES), acrylic acid (Acrylates), and polyethylene glycol (PEG) in a mass ratio of 41-43 wt% : 27-29 wt% : 28-31 wt%; in the deep eutectic solvent, the molar ratio of choline chloride (ChCl) and hydrogen bond donor ethylene glycol (EG) is 1:1.9-2.1.

[0024] As an alternative, the device also includes an adhesive layer disposed between the electrode layer and the substrate layer, through which the device is adhered to the skin; the material of the adhesive layer is modified polydimethylsiloxane (PDMS); the modified polydimethylsiloxane (PDMS) is prepared by mixing a PDMS solution with ethoxylated polyethyleneimine (PEIE) at a mass ratio of 250:1.

[0025] As an optional solution, the substrate layer is made of PDMS material; or, when the substrate layer is made of PI material, it further includes an encapsulation layer located outside the substrate layer; or, when the substrate layer is prepared using modified polydimethylsiloxane (PDMS) material doped with ethoxylated polyethyleneimine, it further includes an encapsulation layer located outside the substrate layer; the material of the encapsulation layer is PDMS, PU, ​​or silicone rubber.

[0026] As an alternative, the device further includes a circuit board electrically connected to the first conductive electrode, the second conductive electrode, and the third conductive electrode in the electrode layer; the circuit board is disposed between the adhesion layer and the substrate layer, or the circuit board is disposed between the encapsulation layer and the substrate layer, for preprocessing the mixed signal and the compensation signal.

[0027] A second aspect of this invention discloses an electrophysiological signal acquisition system capable of removing motion artifacts, comprising:

[0028] The electrophysiological signal acquisition device according to any one of the first aspect and optional solutions of the present invention;

[0029] The signal processing module is configured to process the mixed signal and compensation signal output by the electrophysiological signal acquisition device through a pre-stored neural network algorithm model constructed by combining 1D-CNN and bidirectional LSTM, and use the compensation signal to remove motion artifacts in the original electrophysiological signal to obtain the electrophysiological signal.

[0030] The present invention has the following beneficial effects:

[0031] The electrophysiological signal acquisition device with motion artifact sensing function provided by this invention achieves stable sensing of the interface between the ion gel material and the skin through a coplanar composite structure design combined with a composite sensing layer made of ion gel material. With the help of patterned conductive electrodes in the electrode layer, two signal acquisition channels are formed. It can actively sense and output motion artifacts on the skin surface caused by daily behaviors such as breathing, sweating, and movement while wearing and continuously monitoring the original electrophysiological signals. The motion artifact signal can be used as a compensation for the original electrophysiological signal to obtain a clean electrophysiological signal.

[0032] The electrophysiological signal acquisition device with motion artifact detection function provided by this invention uses a stretchable self-adhesive ionogel as the composite sensing layer material. Testing has shown that this ionogel not only possesses the high flexibility of hydrogels (>1500% stretchability) but also the ionic conductivity of deep eutectic solvents (1 mS / cm), along with excellent biocompatibility, adhesion properties (69 N / m), and mechanical stability. By optimizing the adhesion and stability of the sensing layer, stable contact between the electrode and the skin can be maintained, effectively avoiding signal loss and baseline drift caused by electrode displacement, detachment, or poor contact, thus improving the reliability of electrophysiological signal acquisition in dynamic environments.

[0033] The electrophysiological signal acquisition device with motion artifact sensing function provided by this invention can also introduce a coplanar damping unit in the composite sensing layer. The damping unit can effectively absorb and buffer low-frequency disturbances caused by motion, dissipate energy, reduce motion artifacts and other noise interference from the source, and significantly improve the stability and accuracy of electrophysiological signal acquisition in dynamic environments, which is superior to traditional technical solutions that rely on back-end filtering algorithms.

[0034] The electrophysiological signal acquisition device with motion artifact sensing function provided by this invention can be applied to wearable and continuous monitoring scenarios to acquire electrophysiological signals such as electrocardiogram (ECG), electromyography (EMG), electroencephalogram (EEG), and electrooculogram (EOG), and has very good application prospects. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the electrophysiological data acquisition device;

[0036] Figure 2 This is a schematic diagram of the structure of three composite sensing layers;

[0037] Figure 3 This is another structural schematic diagram of the electrophysiological signal acquisition device of the present invention;

[0038] Figure 4 This is a schematic diagram illustrating the principle of skin ionization interface sensing.

[0039] Figure 5 Equivalent circuit diagram of skin ionization interface sensing;

[0040] Figure 6 This is a schematic diagram of the deep denoising model structure;

[0041] Figure 7 The graph shows the mechanical properties of the ion gel from the original signal acquisition unit.

[0042] Figure 8 The image shows the electrical properties of the ion gel in the original signal acquisition unit.

[0043] Figure 9 Biocompatibility characterization diagram of the ion gel of the original signal acquisition unit;

[0044] Figure 10 A comparative test image showing the skin adhesion of the ion gel from the original signal acquisition unit to commercial medical tape.

[0045] Figure 11 A comparison chart of the elastic modulus of ordinary PDMS and modified PDMS used in the original signal acquisition unit of this invention;

[0046] Figure 12 The original signal acquisition unit of this invention uses a modified PDMS skin adhesion test diagram;

[0047] Figure 13 In the image, (a) is an ECG signal image with motion artifacts acquired by the commercial BioPac physiological signal acquisition system; (b) is an ECG signal image without motion artifacts acquired by the electrophysiological signal acquisition system of the present invention.

[0048] Figure 14 The image shows the experimental results of ECG signals acquired under 1Hz artificial vibration.

[0049] Figure 15 The image shows the experimental results of ECG signals acquired under an applied 2Hz artificial vibration.

[0050] Figure 16 The image shows the experimental results of ECG signals acquired under 5Hz artificial vibration.

[0051] Figure 17 The diagram shows the T / R value distribution of the present invention and the comparative scheme under dynamic vibration environment.

[0052] Figure captions: 100-Composite sensing layer, 101-Original signal acquisition unit, 102-Ionization sensing positive electrode sub-unit, 103-Ionization sensing negative electrode sub-unit, 104-Damping unit, 200-Electrode layer, 300-Base layer, 400-Encapsulation layer, 500-Adhesion layer, 600-Circuit board; 700-Host computer. Detailed Implementation

[0053] This invention takes electrocardiogram (ECG) signal acquisition as an example. Currently, clinical and commercial devices commonly use Ag / AgCl gel electrodes (as a sensitive element in direct contact with the skin) in conjunction with lead wires and electrode clips / fasteners as the signal acquisition end. These gel electrodes provide low contact impedance under resting conditions, making them suitable for short-term, high-precision monitoring. However, these electrodes have significant limitations in dynamic monitoring: First, the gel electrodes are prone to moisture evaporation during prolonged use, leading to gel drying and a significant increase in electrode-skin interface impedance, resulting in weakened signal amplitude and waveform distortion. Second, the adhesion between these electrodes and the skin is limited, especially during strenuous exercise or daily activities, where the electrodes are prone to displacement or detachment, easily producing motion artifacts and causing a decrease in signal-to-noise ratio, affecting the reliable acquisition and subsequent analysis of the original signal. Furthermore, because this gel material contains a high concentration of electrolytic salts and aqueous gel, prolonged contact with the skin surface can easily disrupt the water-salt balance of the stratum corneum, and may also cause skin allergies or irritation under mechanical friction and sweat, limiting its application in long-term dynamic monitoring.

[0054] This application takes into account that the skin surface itself contains moisture and various ions, such as sodium ions (Na+). + ) and chloride ions (Cl - These ions can migrate freely within the micropores and multilayered structure of the skin. When a sensing layer made of ionogel material comes into contact with the skin, an "ion-electron interface" is formed between the skin surface, the migratable ions in the ionogel material, and the conductive electrodes, such as... Figure 4 As shown, similar to a double-layer structure, this can not only effectively transmit minute potential changes on the skin surface to the conductive electrode, but also buffer signal fluctuations caused by micro-displacements at the interface.

[0055] Based on this, the present invention proposes an electrophysiological signal acquisition device based on skin ionization sensing. Building upon the traditional electrophysiological signal acquisition structure, it introduces a skin ionization sensing mechanism. Through the structural design of a coplanar composite sensing layer that directly contacts the skin, it can detect minute displacements and changes in contact state between the composite sensing layer and the skin in real time. This solves the problem that rigid inertial devices in existing active artifact suppression strategies cannot reflect dynamic changes at the composite sensing layer-skin interface. It can actively sense motion artifact signals under dynamic conditions, and combined with a signal compensation mechanism, achieve signal compensation and noise suppression of the original electrophysiological signal, thus realizing accurate electrophysiological signal acquisition.

[0056] The electrophysiological signal acquisition device integrates a raw signal acquisition channel and an ionotropic sensing channel, both designed in a coplanar manner. The raw signal acquisition channel acquires raw electrophysiological signals such as electrocardiograms and electromyograms; the ionotropic sensing channel detects interface changes caused by skin deformation or movement. Correspondingly, the electrophysiological signal acquisition device outputs two signals: one is the raw electrophysiological signal, which carries motion artifact signals and is therefore also called a mixed signal; the other is the ionotropic sensing motion artifact signal, used to characterize the dynamic disturbance at the interface between the ionogel material and the skin, also called a compensation signal. Both signals can be simultaneously input to the signal processing circuit and the host computer. Then, based on the ionotropic sensing motion artifact signal, combined with algorithms such as adaptive filtering, active noise reduction and real-time correction of the raw electrophysiological signal are achieved. This enables real-time sensing and active compensation of interface disturbances in dynamic environments, significantly improving the stability and accuracy of electrophysiological signal acquisition.

[0057] The following detailed description, in conjunction with specific embodiments, further illustrates the product structure, material characteristics, and working principle of the present invention.

[0058] like Figure 1 As shown in Example 1, an electrophysiological signal acquisition device with motion artifact sensing function (hereinafter referred to as "electrophysiological signal acquisition device" or "the device") is disclosed. As a front-end device for electrophysiological signal acquisition, it is mainly responsible for acquiring raw electrophysiological signals and motion artifact signals. The device mainly consists of a composite sensing layer 100, an electrode layer 200, a base layer 300, and an encapsulation layer 400, forming an integrated flexible multifunctional structure. The composite sensing layer 100 is composed of multiple raw signal acquisition units 101, ionization sensing units (including ionization sensing positive electrode sub-units 102 and ionization sensing negative electrode sub-units 103), and damping units 104, all coplanarly arranged. During use, the composite sensing layer 100 directly contacts the skin. The composite sensing layer 100 works in conjunction with the electrode layer 200 to achieve coordinated operation of dynamic interface sensing and stable electrical signal acquisition. This device is suitable for various physiological signal monitoring scenarios, including electrocardiograms, electromyograms, electroencephalograms, and electrooculograms, among other electrophysiological signals.

[0059] The functional units, including the ionization sensing unit, the raw signal acquisition unit 101, and the damping unit 104, all exhibit the same microstructure in appearance. Units with the same function share the same microstructure, while different functional units can employ different microstructure designs. To reduce design and fabrication complexity and subsequent data processing, in this embodiment, the microstructures corresponding to different functional units have the same geometric parameters; for example, they are all independent and electrically insulated hexagonal prism microstructures. Multiple raw signal acquisition units 101 constitute a first microstructure array, multiple ionization sensing positive sub-units 102 constitute a second microstructure array, multiple ionization sensing negative sub-units 103 constitute a third microstructure array, and multiple damping units 104 constitute a fourth microstructure array. The second and third microstructure arrays are typically symmetrically designed, with each array staggered on the same plane, maintaining an overall array structure. In the composite sensing layer, adjacent microstructures are arranged at intervals, meaning there is a certain physical distance between each pair, and they are electrically insulated from each other. In other embodiments, the microstructures corresponding to different functional units can also be designed with different geometric shapes or sizes; this invention does not impose such limitations.

[0060] Understandably, electrode layer 200 includes a first conductive electrode electrically connected to each original signal acquisition unit 101 in the first microstructure array. The first conductive electrode adopts a patterned design, and its shape and size parameters match the arrangement and size parameters of the original signal acquisition units 101 in the first microstructure array. Similarly, electrode layer 100 also includes a second conductive electrode electrically connected to each ionization sensing positive electrode sub-unit 102 in the second microstructure array. The second conductive electrode also adopts a patterned design, and its shape and size parameters match the arrangement and size parameters of the ionization sensing positive electrode sub-unit 102 in the second microstructure array. Furthermore, it includes a third conductive electrode electrically connected to each ionization sensing negative electrode sub-unit 103 in the third microstructure array. The third conductive electrode also adopts a patterned design, and its shape and size parameters match the arrangement and size parameters of the ionization sensing negative electrode sub-unit 103 in the third microstructure array.

[0061] The raw signal acquisition unit 101 is mainly used to acquire mixed signals containing electrophysiological signals and motion artifact signals. Specifically, the raw signal acquisition unit 101 can be made of a stretchable, self-adhesive ionogel. This ionogel is typically required to be soft and have good stretchability, good conductivity, resistance to water loss, strong adhesion, and excellent biocompatibility. Through its corresponding first conductive electrode, it can stably output mixed signals containing electrophysiological signals and motion artifact signals.

[0062] In one alternative design, the primary signal acquisition unit 101 utilizes a stretchable self-adhesive ionogel, whose main components are deep eutectic solvent (DES) and acrylic acid (AAc). Compared to traditional ionogel materials, DES provides better ionic conductivity and increases its mechanical strength through a hydrogen bond network structure, making the resulting ionogel suitable for signal acquisition in dynamic environments. Therefore, based on the excellent biocompatibility, adhesion, conductivity, and mechanical stability of this ionogel, the primary signal acquisition unit 100, when used with the first conductive electrode, can achieve stable acquisition of weak electrophysiological signals and also detect motion artifacts caused by skin deformation, sweating, etc.

[0063] The method for preparing stretchable self-adhesive ionogel materials is as follows: First, choline chloride (ChCl) and hydrogen bond donor ethylene glycol (EG) are mixed at a molar ratio of 1:2 and stirred at approximately 100 °C for 2 h to prepare a deep eutectic solvent (DES). Subsequently, acrylic acid, the prepared DES, α-ketoglutaric acid as an initiator, and polyethylene glycol diacrylate (PEGDA) as a crosslinking agent are added to a mixing container in the following mass percentages: 27.9%~29.9%, 69%~71%, 0.9%~1.1%, and 0.09%~0.11%, respectively. The mixture is magnetically stirred and mixed under light-protected conditions to obtain a transparent PAAc-DES ionogel precursor solution.

[0064] For example, in a specific experiment, 2.89 g AAc, 7 g DES, 0.1 g α-ketoglutarate and 0.01 g PEGDA were added to a container in sequence, with the mass ratio of each component being 28.9%:70%:1%:0.1%. They were stirred until completely dissolved to obtain a transparent PAAc-DES precursor solution.

[0065] It is worth noting that in the obtained PAAc-DES ion gel precursor solution, the molar ratio of choline chloride (ChCl) to hydrogen bond donor ethylene glycol (EG) is usually controlled at 1:1.9~2.1. Within this ratio range, DES can participate more fully in ion conduction and form a stable composite structure with the polymer network, ensuring the electrical and mechanical properties of the gel.

[0066] The ionization sensing unit is mainly used to acquire compensation signals. Based on the external ports connected to its conductive electrodes, the ionization sensing unit is divided into a positive ionization sensing sub-unit 102 and a negative ionization sensing sub-unit 103. Understandably, in actual devices, the positive ionization sensing sub-unit 102 and the negative ionization sensing sub-unit 103 do not differ significantly in physical structure and material characteristics. The distinction here is mainly due to the different ports on the PCB circuit connected to their respective conductive electrodes. Of the two ports, one is connected to the signal input terminal (Vin), i.e., the ADC input, and is defined as the positive terminal; the other is connected to the reference terminal (GND), and is defined as the negative terminal, used for excitation and common-mode reference. The two are used in pairs to form a differential circuit.

[0067] In an alternative approach, the material preparation of the ionization sensing unit can be based on the ion gel composition used to prepare the original signal acquisition unit 101, with the addition of fumed silica. Specifically, the aforementioned PAAc-DES ion gel precursor solution and fumed silica are mixed at a mass ratio of approximately 9.5~10.5:1 (preferably 10:1), stirred to dissolve the SiO2 nanoparticles in the ion gel precursor solution, and then ultrasonically vibrated for 30 minutes until the liquid becomes clear, thereby obtaining the ionization sensing unit precursor solution.

[0068] It is worth noting that the addition of SiO2 nanoparticles to the precursor solution of the ionogel can form an inorganic-organic composite support structure within the ionogel, thereby enhancing the mechanical properties of the ionogel and reducing its adhesion to the skin, thus enabling more sensitive acquisition of motion artifact signals. Furthermore, SiO2 can also support and constrain the internal structure of the ionogel, making the migration process of ions within the material more stable. This improves the stability and consistency of the material's electrical response under dynamic deformation conditions without significantly affecting its ionic conductivity, thereby enhancing the sensing sensitivity and reliability of the ionogel for mechanical disturbances and motion-related signals.

[0069] It is worth noting that the ionization sensing unit uses an ion-conducting material with lower adhesion than the original signal acquisition unit. This material is extremely sensitive to minute changes at the skin interface and can output dynamic signals related to motion artifacts in real time. These dynamic signals reflect artifacts caused by perturbations at the skin-composite ionization sensing layer interface, providing a valuable reference for subsequent signal processing algorithms. This allows for artifact compensation of the original physiological signals, improving the stability and reliability of the final acquired signal.

[0070] The damping unit 104, by forming a network structure with both viscoelastic and energy dissipation characteristics, can absorb and attenuate the transmission of mechanical stress under tension, bending, and mechanical disturbance conditions, preventing disturbances from directly acting on the flexible electrode interface, thereby improving stability and effectively suppressing motion artifacts from interfering with signal acquisition. In an optional embodiment, the damping unit 104 can be prepared using composite materials such as deep eutectic solvent (DES), acrylic acid (Acrylates), and polyethylene glycol (PEG).

[0071] The preparation process of damping unit 104 material is as follows: choline chloride (ChCl) and hydrogen bond donor ethylene glycol (EG) are mixed at a molar ratio of 1:2 to prepare a deep eutectic solvent (DES), and stirred at 100℃ for about 2 hours; subsequently, DES and polyethylene glycol (PEG) are mixed at a mass percentage of 42%:28%, and heated and stirred until the PEG is completely dissolved; then, 28.9% acrylic acid (AAc), 1% α-ketoglutarate (initiator), and 0.1% PEGDA (crosslinking agent) are added to the system by mass percentage, and the mixture is heated and stirred in a one-pot manner until the solution is clear, obtaining the damping unit precursor solution.

[0072] For example, in a specific experiment, 4.2 g of DESs and 2.8 g of PEG were mixed and heated until dissolved; then 2.89 g of AAc, 0.1 g of α-ketoglutarate and 0.01 g of PEGDA were added, and the mixture was heated and stirred until clear and then solidified to obtain the damping unit precursor solution.

[0073] It is worth noting that the mass ratio of deep eutectic solvent (DES), acrylic acid, and polyethylene glycol (PEG) in the final damping unit precursor solution can be controlled within the range of 41-43 wt% : 27-29 wt% : 28-31 wt%, respectively. In a preferred embodiment, the mass percentages are 42 wt%, 28 wt%, and 28.9 wt%, respectively. It can also be observed that the damping unit 104 incorporates polyethylene glycol (PEG) based on the same acrylic acid system (PAAc-DES ionogel precursor solution). Compared with other materials, polyethylene glycol (PEG) has a higher energy dissipation factor (tanδ), enabling the material to effectively absorb noise generated by low-frequency disturbances in dynamic environments, mitigating the impact of external interferences such as mechanical shock and stretching on signal quality, and improving the stability of electrophysiological signals.

[0074] It is worth noting that the composite sensing layer 100 is constructed as described above. Different functional units differ in materials. This invention does not impose any particular restrictions on their structural form and arrangement. However, from the perspective of manufacturing cost, each functional unit in the composite sensing layer is usually designed to have the same geometric parameters, including geometric shape and size parameters, and the overall arrangement is designed as a periodic array. Typically, a raw signal acquisition unit 101 is arranged adjacent to at least one damping unit 104, a pair of ionization sensing positive electrode sub-units 102 and ionization sensing negative electrode sub-units 103.

[0075] Typical, such as Figure 1 As shown, a repetitive unit module consists of a primary signal acquisition unit 101, two pairs of ionization sensing units, and two damping units 104. This unit module has a hexagonal close-packed lattice structure. The primary signal acquisition unit 101 is located at the center of the hexagonal close-packed lattice. The ionization sensing positive electrode sub-unit 102, the ionization sensing negative electrode sub-unit 103, and the damping unit 104 are located at six lattice points of the same hexagonal close-packed lattice and are arranged alternately in sequence. In this repetitive unit module, the microstructure corresponding to each functional unit is a regular hexagonal prism structure with a side length of approximately 1.3 mm and a thickness of approximately 0.5–1 mm. In the overall arrangement, a spacing of 0.1–0.2 mm is maintained between adjacent microstructures.

[0076] Typical, such as Figure 2 As shown in (a), a repeating unit module consists of six functional units: a primary signal acquisition unit 101, a pair of ionization sensing units, and a damping unit 104. The primary signal acquisition unit 101 is located in the middle, with the ionization sensing positive and negative sub-units 102 and ionization sensing negative located on either side and staggered. The damping unit 104 is located between the pair of ionization sensing units and adjacent to the primary signal acquisition unit 101, forming a rectangular array. Each functional unit is located at one of the four lattice points of the same square lattice and is staggered from each other. In this repeating unit module, the microstructures corresponding to each functional unit are designed as cylindrical structures of equal diameter. A spacing of 0.1–0.2 mm is maintained between adjacent microstructures in the overall arrangement.

[0077] It should be noted that in other embodiments, the composite sensing layer may not include the damping unit 104. Although the device performance will be somewhat reduced, it can still achieve basic sensing functions. Typically, such as... Figure 2 (b) and Figure 2 As shown in (c), the repeating unit module includes only the original signal acquisition unit 101, the ionization sensing positive pole sub-unit 102 and the ionization sensing negative pole sub-unit 103, and does not include the damping unit 104. Figure 2In (b) of the model, each functional unit in the unit module is a hexagonal prism structure with equal side length; Figure 2 In (c), the original signal acquisition unit 101 in the repeating unit module is a rectangular column structure, while the ionization sensing positive pole sub-unit 102 and the ionization sensing negative pole sub-unit 103 are square column structures, and the original signal acquisition unit 101 is aligned with a pair of ionization sensing positive and negative pole sub-units.

[0078] Therefore, the repeating unit module, as the smallest repeating unit, can be four functional units arranged in a square lattice; or the smallest repeating unit can include more than four functional units, meaning some functional units are greater than one. The microstructure shapes corresponding to each functional unit can be the same or different, typically cylindrical, prismatic, or square pillar structures, or other irregular structures. Furthermore, the dimensional parameters of the microstructures corresponding to each functional unit are not required to be completely identical. The array of microstructures still forms an array structure, also called an overall microstructure array, which can typically be in the form of a hexagonal lattice (including hexagonal close-packed lattices), a square lattice (including rectangular lattices), a rectangular lattice, or an oblique lattice.

[0079] As described above, the electrode layer 200 is connected to the composite sensing layer 100 and has patterned electrodes that are respectively connected to the original signal acquisition unit 101 and the ionization sensing positive and negative electrode sub-units 102 and ionization sensing negative in the composite sensing layer 100, thereby realizing independent acquisition and split output of the two types of signals. The electrophysiological and ionization sensing signals are transmitted to the input ports of the signal processing circuit via conductive electrodes, respectively, to achieve signal separation and artifact compensation in subsequent circuit and algorithm processing.

[0080] Each conductive electrode can be made of silver paste or PEDOT:PSS conductive polymer. Silver paste has excellent conductivity and is suitable for signal acquisition in static or low-deformation environments. PEDOT:PSS material combines high conductivity with excellent flexibility and tensile strength, maintaining stable conductivity under large deformation and long-term wear conditions, thereby improving the overall reliability and wearability of the module.

[0081] The three functional units in the composite sensing layer are structurally coplanarly distributed and functionally work synergistically. Specifically, the ionization sensing unit and its corresponding conductive electrode form a capacitive ionization sensing channel, outputting a compensation signal reflecting motion artifacts; the raw signal acquisition unit and its corresponding conductive electrode form a raw signal acquisition channel, outputting a mixed signal containing both surface electrophysiological signal components and artifact components; and the damping unit provides mechanical buffering and structural support, absorbing low-frequency disturbances and mitigating the impact of external noise on signal acquisition. The combined composite sensing layer and electrode layer enable real-time detection of interface disturbances and adaptive signal compensation in dynamic environments, significantly improving the stability and accuracy of electrophysiological signal acquisition.

[0082] In this embodiment, the substrate 300 is made of polyimide (PI) material and serves as the substrate for the electrode wiring. PI material possesses characteristics such as flexibility, excellent insulation, and good mechanical strength. Therefore, for applications requiring precise circuit shaping or multilayer interconnection, a PI substrate is preferred as the substrate for the electrode wiring, thereby achieving integrated fabrication and reliable support for the electrode wiring.

[0083] The encapsulation layer 400 is made of polydimethylsiloxane (PDMS) to reduce the impact of external mechanical disturbances, improve the mechanical stability of the device, and maintain flexibility and wearability to ensure the reliability of long-term monitoring. It is worth noting that PDMS material has excellent flexibility, biocompatibility, and breathability, allowing it to adhere to the skin for extended periods without causing irritation. Therefore, in other embodiments, the PI substrate layer can be omitted, and the PDMS layer can be used directly as the substrate layer to further improve the overall flexibility and fit of the device. Of course, in addition to PDMS, the encapsulation layer 400 can also be made of flexible materials such as polyurethane (PU) or silicone rubber; the appropriate material can be selected based on application requirements to achieve the best encapsulation effect.

[0084] With the synergistic effect of the composite sensing layer 100 and the electrode layer 200, both raw electrophysiological signals (i.e., a mixed signal including electrophysiological signals and motion artifact signals) and motion artifact signals (i.e., compensation signals) can be acquired simultaneously. The device can simultaneously acquire two types of signals: one is the mixed signal output from the raw signal acquisition channel, including surface electrophysiological signals and motion-induced artifact components; the other is the motion artifact signal output from the ionization sensing channel, mainly reflecting interface interference caused by daily activities such as movement, respiration, skin deformation, and sweating. Both types of signals are transmitted to the processing circuit via conductive electrodes for subsequent real-time artifact removal and signal reconstruction processing, thereby obtaining a high signal-to-noise ratio and accurate electrophysiological signal output.

[0085] It is worth noting that the composite sensing layer 100 is made of ionogel material, which can increase the interfacial contact area and reduce interfacial impedance, allowing weak potential differences on the body surface to be smoothly transmitted to the flexible electrode. The conductive electrode forms an electron-ion interface with the ionogel material and the skin surface, which can convert ionic current into electronic current. After filtering and other processing, the target electrophysiological signal (i.e., a clean electrophysiological signal) can be obtained. The damping unit 104 is adjacent to the two types of functional units. Through its viscoelastic network structure, it absorbs and attenuates external mechanical stress, preventing interfacial disturbances from directly acting on the signal acquisition area, and further improving the stability of the signal from a mechanical perspective. Through this synergistic mechanism, the composite sensing layer 100 achieves an organic combination of interfacial disturbance detection, electrical signal acquisition, and mechanical stability control, and can continuously output high-fidelity electrophysiological signals in dynamic environments.

[0086] Based on the above structural and material characteristics, the electrode layer 200 and the composite sensing layer 100 in the electrophysiological signal acquisition device can be fabricated using an aerosol device and an electronic additive printing platform, respectively. The specific fabrication process is as follows:

[0087] The first step is to use an aerosol device to print silver paste lines on the substrate to form patterned electrodes, thus completing the electrode layer fabrication.

[0088] The second step involves pouring a pre-prepared ionogel precursor solution with stretchable self-adhesive properties into the printing barrel of the electronic additive printing platform. The barrel and needle are then installed, and the printing speed (2mm / s-4mm / s), air pressure (5psi-10psi), and needle spacing (40µm-100µm) are adjusted until a solid regular hexagonal prism is uniformly printed. After parameter testing, the composite sensing layer drawing (including the original signal acquisition unit layer, the ionization sensing unit layer, and the damping unit layer) is imported. The fabricated electrode layer is placed on the printing platform, and after positioning, the original signal acquisition unit layer is selected to begin printing. During printing, the solution is uniformly pumped from the needle, forming a clearly defined and uniformly thick conductive electrode pattern. After printing, the pattern is placed in a curing chamber for 5 minutes to form a microstructure array serving as the original signal acquisition unit.

[0089] The third step is to clean the work surface, replace the barrel with a new barrel containing the precursor solution of the ionization sensing unit material, repeat the operation of the second step, select the ionization sensing unit layer to start printing, and form a microstructure array as the ionization sensing unit.

[0090] The fourth step involves cleaning the work surface, replacing the printing cylinder with a new one containing the damping material precursor solution, and repeating the steps from step two. This time, the damping unit layer is selected for printing, forming a microstructure array that serves as the damping unit. The final printed result is a composite sensing layer composed of three materials.

[0091] Furthermore, to optimize the interface adhesion of each functional layer in the device, as well as the signal processing capability and system stability, an adhesion layer 500 can be added based on Embodiment 1. For example... Figure 3 As shown, the adhesion layer 500 is disposed between the substrate layer 300 and the electrode layer 200, that is, directly connected to the flexible electrode. The composite sensing layer 100 and the electrode layer 200 are usually the same or similar in shape and size, and can be modularly designed. The non-sensing functional layers such as the adhesion layer 500 and the substrate layer 300 are usually the same or similar in shape and size, and are usually larger than the composite sensing layer 100 and the electrode layer 200. At least one sensing module can be disposed on the surface. Figure 3 It includes two sensing modules, so the area of ​​the surface of the adhesive layer 500 that is not covered by the sensing modules can directly adhere to the skin surface, thus attaching the device well to the skin surface.

[0092] In one alternative, the adhesive layer 500 can be made of a modified polydimethylsiloxane (PDMS) material, which achieves heterogeneous regulation of the crosslinking network by introducing ethoxylated polyethyleneimine (PEIE), giving PDMS a lower modulus and higher adhesion.

[0093] The preparation process of the adhesion layer 500 is as follows: PDMS prepolymer and crosslinking agent are mixed at a mass ratio of 10:1 and degassed to form a PDMS solution; then, 40 μL of ethoxylated polyethyleneimine (PEIE) is added to every 10 g of PDMS, and the mixture is stirred evenly and degassed again; after degassed treatment, it is dried at 80℃ for 1 h to obtain the modified PDMS material. The mass ratio of PDMS solution to ethoxylated polyethyleneimine (PEIE) is approximately 250:1.

[0094] Understandably, PDMS, as a material matrix, possesses high flexibility, good biocompatibility, and mechanical stability, and is widely used in medical and wearable devices. The curing of PDMS is primarily catalyzed by platinum catalysts. In this invention, by introducing PEIE into the original PDMS material, the amine groups in the PEIE molecules undergo strong coordination with the platinum catalyst, "poisoning" or "consuming" the surrounding platinum catalyst. This results in the cross-linking reaction being inhibited in the area surrounding the PEIE, while areas far from the PEIE undergo normal cross-linking, ultimately forming a non-uniform PDMS cross-linked network. The loose regions with low cross-linking density are easily deformable, making the material overall softer (low modulus) and more extensible (high elongation at break), better adapting to skin surface deformation and significantly improving adhesion, enabling the material to better adapt to the dynamic skin environment. Therefore, the modified PDMS provided by this invention, by introducing a small amount of ethoxylated polyethyleneimine (PEIE) into the traditional PDMS matrix to regulate the cross-linking network, achieves low modulus, high tensile strength, and enhanced skin adhesion, thereby enhancing the fit of the device during wear and reducing device displacement and detachment.

[0095] like Figure 4 As shown, the electrophysiological signal acquisition device employs a dual-channel acquisition structure: a primary signal acquisition channel, directly attached to the skin, acquires weak, raw electrophysiological signals (potentially in the millivolt range), including electrophysiological signals and motion artifacts; the ionotropic sensing channel, based on the coupling interface formed between the composite sensing layer and the skin, monitors the displacement or deformation of the skin surface in real time and outputs a compensation signal. Specifically, when the gap or geometric structure between the skin and the composite sensing layer changes due to daily activities such as movement, respiration, and sweating, the coupling capacitance C of this interface changes accordingly, thereby generating a corresponding induced voltage signal at the coupling interface to reflect the interface disturbance caused by movement. Wherein, R... issueThis represents the tissue impedance of the skin surface layer, which is included in the mixed signal and is usually regarded as a constant in the equivalent circuit. For example, for skin with a thick stratum corneum (palms / soles): 100 kΩ ~ 1 MΩ; for skin with a thin stratum corneum (forearms / upper arms): 10 kΩ ~ 100 kΩ.

[0096] Combination Figure 5 As shown, from the equivalent circuit model of the device and its interface, it can be seen that the skin impedance is... The mixed signal is acquired by the original signal acquisition channel and can be labeled as node V. The coupling interface capacitance between the composite sensing layer and the skin is represented by C1 and C2 in the equivalent circuit and is acquired by the ionization sensing channel. C1 and C2 both reflect the coupling capacitance between the composite sensing layer and the skin, and their capacitance dynamically changes with the interface distance or contact deformation caused by skin movement. It should be noted that C1 and C2 do not represent two different types of capacitors, but rather... Figure 4 The off-electric sensing unit in the circuit model is equivalently split into different spatial regions (i.e.) Figure 1 Two off-grid sensing units are located adjacent to the original signal acquisition unit, thereby simulating the distribution and changes of interface capacitance more accurately.

[0097] The electrophysiological signal acquisition device simultaneously acquires and outputs the change signals of node V and coupling capacitance C. The mixed signal output from the raw signal acquisition channel contains real and weak physiological electrical signals and motion artifact signals, while the off-current sensing channel outputs motion artifact signals (i.e., compensation signals). After receiving the above signals, the host computer analyzes and compensates them through algorithms, effectively distinguishing interface disturbance signals from physiological signals and eliminating artifacts caused by daily activities such as movement. This achieves active sensing and effective removal of motion artifacts, significantly improving the stability and signal-to-noise ratio of electrophysiological signals, thereby outputting high signal-to-noise ratio, stable, and accurate electrophysiological signals.

[0098] Furthermore, the signal processing functionality of the device provided in Embodiment 1 can be expanded. Specifically, in the electrophysiological signal acquisition device, the integrated circuit board 600, or circuit board 600, is arranged between the substrate layer 300 and the encapsulation layer 400. Specifically, it can be a PCB circuit board or an FPC circuit board, etc. Continuing with... Figure 3 As shown, the pins in the circuit board 600 are connected to the conductive electrodes in the electrode layer 200 after passing through the pre-drilled through holes in the substrate layer 300 and the adhesive layer 500, thereby forming an integrated device with electrophysiological signal acquisition and preprocessing functions.

[0099] It is worth noting that this integrated design not only ensures a stable connection between the conductive electrodes in the electrode layer 200 and the circuit board 600, but also minimizes the electrical signal path between the conductive electrodes and the circuit board 600, reducing contact impedance and noise interference.

[0100] The analog front-end signal conditioning module integrated in circuit board 600 simultaneously amplifies and filters the mixed signal output from the original signal acquisition channel and the compensated signal output from the off-electric sensing channel. The analog front-end signal conditioning module is equipped with a low-noise amplification unit, an analog filtering unit, and an analog-to-digital converter (ADC), used for amplitude amplification, bandwidth limiting, and digital sampling of weak electrophysiological signals, respectively. Then, the two output signals are wirelessly transmitted to a host computer via the built-in Bluetooth module of circuit board 600, enabling real-time signal transmission and online analysis. This design integrates signal acquisition, signal preprocessing, and signal transmission functions into one unit, enhancing the device's high integration and reliability.

[0101] It should be noted that the electrophysiological signal acquisition device provided by this invention is only used for signal acquisition and preprocessing; signal analysis and extraction can be performed by a host computer. For example, the output electrical signal can be transformed from the time domain to the frequency domain using a Fast Fourier Transform (FFT), and then noise associated with motion artifacts can be estimated and subtracted from the mixed signal in real time using adaptive filtering, thereby obtaining a clean electrophysiological signal (i.e., the target electrophysiological signal) with motion artifacts removed.

[0102] Furthermore, the present invention also provides an electrophysiological signal acquisition system, which consists of an electrophysiological signal acquisition device and a host computer 700. The host computer 700 receives two types of signals output by the electrophysiological signal acquisition device, processes the two types of signals through a pre-stored deep denoising model, and obtains the final electrophysiological signal output.

[0103] Understandably, the host computer 700 includes at least a processor, a memory, and a communication module. The memory stores computer instructions for deep denoising, the processor executes these instructions, and the communication module can specifically be a Bluetooth module to communicate with the Bluetooth module of the circuit board 600 in the electrophysiological signal acquisition device to receive both types of signals. The host computer 700 can be a smartphone, tablet, or other terminal, as long as it can perform data processing; this invention does not impose any limitations on this.

[0104] Combination Figure 6As shown, the neural network algorithm model for deep denoising is constructed by combining 1D-CNN and bidirectional LSTM to remove motion artifacts from the original electrophysiological signal. The model input is a two-dimensional temporal signal, consisting of a Noised Signal (compensation signal) and an Interface Signal (mixed signal), with a time step of 200. The two signals are jointly represented in a multi-channel form at the input layer and then fed into the subsequent network for feature learning. For the input signal, the model uses multiple one-dimensional convolutional layers (1D-CNN) to extract local feature patterns in the temporal dimension. Each convolutional layer has a kernel size of 3, and a ReLU activation function is used to introduce nonlinear characteristics. Batch normalization is also used to stabilize the training process and prevent gradient vanishing or exploding. Subsequently, the temporal features output by the convolutional network are fed as input into multiple bidirectional LSTM layers to further model the global temporal dependencies of the signal in the forward and reverse time dimensions. Finally, the extracted global temporal features are mapped through fully connected layers and reconstructed via regression layers to remove motion artifacts from the electrophysiological signal. This neural network algorithm model can output clean electrophysiological signals based on the input time series signals, and is suitable for tasks such as signal denoising and time series regression.

[0105] To further verify the effects achievable by the present invention, the present invention also conducted a detailed performance characterization of the composite sensing layer of the electrophysiological signal acquisition device to ensure that it meets the requirements for electrophysiological signal acquisition and motion artifact removal.

[0106] from Figure 7 The stress-strain curves of the ionogel materials shown indicate that the ionogel materials corresponding to the original signal acquisition unit and the ionization sensing unit in the composite sensing layer exhibit excellent mechanical properties in the tensile test. Among them, the maximum strain of the ionogel material of the original signal acquisition unit exceeds 1500%.

[0107] The elastic modulus of the ionogel material corresponding to the original signal acquisition unit can be calculated using the elastic modulus calculation formula. The elastic modulus is approximately 4.42 kPa, demonstrating its good flexibility and adaptability in dynamic skin environments. In contrast, the elastic modulus of the ionogel material with the addition of 10 wt% SiO2 increased to 15.37 kPa, significantly enhancing the material's mechanical support capacity while maintaining flexibility. The calculation process is as follows:

[0108] =Δ / Δ =0.442 / 10%=4.42 kPa.

[0109] In the formula, Δ Δ represents the stress change within the strain range of 10% to 20%. It represents the change in strain.

[0110] like Figure 8 As shown, based on the conversion relationship between impedance and conductivity = / ( Both ionogel materials exhibit an ionic conductivity of 1 mS / cm, ensuring effective electrical signal transmission. The conductivity of the ionogel material corresponding to the original signal acquisition unit is used as a reference. For example, the calculation process is as follows:

[0111] = / ( ) = 0.05 / (167.441284458) 0.283) = 1 mS / cm.

[0112] In the formula, This indicates the thickness of the ionogel test sample. This represents the equivalent resistance value of the ion gel sample under low-frequency conditions. This indicates the effective contact area of ​​the ionogel test specimen.

[0113] The biocompatibility of the ion gel material proposed in this invention was compared with that of the traditional Ag / AgCl gel electrode. Figure 9 This is a comparison chart of the biocompatibility tests of the two materials. (Example) Figure 9 As shown, both a traditional Ag / AgCl gel electrode and the ion gel material proposed in this invention were simultaneously applied to the human arm and left for 8 hours. Upon removal, redness and swelling were observed at the application site of the traditional Ag / AgCl gel electrode. In contrast, the ion gel material proposed in this invention passed biocompatibility testing, showing no redness, swelling, or allergic reactions after 8 hours of application, demonstrating its non-irritating nature and suitability for prolonged wear.

[0114] The skin adhesion of the ionic gel proposed in this invention and commercial medical tape were compared in a skin adhesion test. Figure 10 The image shows a comparison of the skin adhesion of the two materials. It can be seen that the adhesion performance of commercial medical tape is about 50.21 N / m, while the adhesion performance of the ion gel material proposed in this invention can reach 69 N / m. This indicates that it can ensure stable contact between the electrode and the skin and avoid signal loss due to electrode displacement or detachment.

[0115] Furthermore, the present invention has also verified the performance of the adhesion layer material. For example... Figure 11As shown, the modified PDMS used in the adhesion layer has an elastic modulus of approximately 197.56 kPa, while the elastic modulus of unmodified conventional PDMS is approximately 613.7 kPa. It can be seen that the modified PDMS proposed in this invention is softer than conventional PDMS, can adapt to the dynamic deformation of the skin, effectively prevents electrode displacement or detachment, and thus improves the stability of signal acquisition.

[0116] like Figure 12 As shown, the skin adhesion energy of the modified PDMS material is 39.5266 N / m. Traditional PDMS, due to its extremely low intrinsic surface energy, is generally considered to be almost non-sticky and thus lacks effective skin adhesion. Therefore, a comparative example of traditional PDMS was not included in this test. Compared to the non-stick properties of traditional PDMS, the modified PDMS proposed in this invention significantly improves adhesion, ensuring stable contact with the skin.

[0117] The test results above demonstrate that, through optimized selection and preparation of existing materials, combined with their superior performance in sensing artifacts, signal acquisition, and energy dissipation, the electrophysiological signal acquisition device of this invention can effectively remove motion artifacts. Furthermore, these materials are simple in composition and preparation methods, and possess good biocompatibility, flexibility, conductivity, and adhesion. They also provide long-term stability and comfort in dynamic environments, meeting the needs of wearable devices for flexible and efficient signal acquisition.

[0118] The electrophysiological signal acquisition device of this invention synchronously transmits a mixed signal (containing electrophysiological signals and motion artifact signals) and a compensation signal (motion artifact signal) to a host computer. The host computer filters the mixed signal and the compensation signal, transforms the signal from the time domain to the frequency domain using a Fast Fourier Transform (FFT), and then estimates and subtracts noise related to the motion artifact signal from the mixed signal in real time using adaptive filtering, thus achieving motion artifact removal. Alternatively, in an optional embodiment of this invention, the filtering and time-frequency conversion processing of the original mixed signal and the compensation signal are performed by a flexible circuit board, thereby integrating real-time front-end signal acquisition and preprocessing.

[0119] Furthermore, to verify the effectiveness of the electrophysiological signal acquisition device proposed in this invention in removing motion artifacts under dynamic conditions, a comparative experiment was conducted using the commercially available BioPac physiological signal acquisition device (which acquires electrophysiological signals via Ag / AgCl electrodes). Taking electrocardiogram (ECG) signal acquisition as an example, the acquisition effect of the device of this invention was verified. In the experiment, volunteers wore two sets of devices simultaneously in both resting and exercise states to acquire ECG signals, ensuring signal consistency.

[0120] Figure 13 This is a comparison chart of ECG signals acquired by two sets of devices. Figure 13(a) shows the ECG signal waveform acquired during motion using a commercial BioPac physiological signal acquisition device, where obvious motion artifacts can be observed. Figure 13 (b) shows the ECG signal acquired using the device of this invention. Under the same motion state, the waveform is stable and clear, and motion artifact interference is significantly reduced. It can be seen that the experimental results fully verify the significant effects of this invention in terms of material structure and signal optimization, and it has a dynamic adaptability that is significantly better than that of traditional Ag / AgCl electrodes.

[0121] To further verify the effectiveness of the skin ionization sensing technology, a simulated ECG monitoring experiment was conducted. Artificial vibrations of 1Hz, 2Hz, and 5Hz were applied to simulate signal interference under dynamic conditions. In the experiment, the ECG data acquisition effects of a commercial BioPac physiological signal acquisition device, a commercial BioPac physiological signal acquisition device with 1Hz, 2Hz, and 5Hz band-stop filters respectively, and the electrophysiological signal acquisition device of this invention were compared under three different dynamic conditions.

[0122] Figure 14 , Figure 15 and Figure 16 The figures show a comparison of the three devices at three different vibration frequencies. It can be seen that, regardless of the vibration frequency, commercial electrodes are subject to varying degrees of periodic vibration artifacts. Even with a band-stop filter matching the vibration frequency, baseline fluctuations and waveform distortion in the signal remain significant. In contrast, the electrophysiological signal acquisition device of this invention maintains clear and stable ECG waveform characteristics at all frequencies, with distinct waveform features and significantly reduced artifact interference. This result demonstrates that the ECG signal acquisition device based on skin ionization sensing of this invention does not rely on back-end digital filtering, but effectively suppresses the influence of mechanical disturbances on electrophysiological signals at the interface of signal generation and transmission, thus exhibiting superior anti-interference capabilities compared to the traditional "electrode + filter" scheme under simulated dynamic interference conditions.

[0123] Understandably, in the evaluation of electrocardiogram (ECG) signal quality, the T / R ratio is usually used to measure signal quality. The T / R ratio reflects the ratio of the amplitude of the T wave to the amplitude of the R wave in the ECG waveform. The stability of the T / R ratio can be used to quantitatively evaluate the quality of the ECG signal under dynamic conditions. The more concentrated the T / R values, the better the consistency of multiple measurement results, and the more stable and higher the signal quality.

[0124] Therefore, this invention subtracts the maximum and minimum T / R values ​​measured within 3 minutes to represent the measurement deviation. For example... Figure 17As shown, under vibration interference conditions of 1 Hz, 2 Hz, and 5 Hz, both the commercial BioPac physiological signal acquisition device and the commercial BioPac physiological signal acquisition device with digital filtering exhibit large T / R value dispersion ranges, wide upper and lower quartile differences in the box plots, and numerous outliers, indicating that they are significantly affected by motion artifacts under dynamic conditions. In contrast, the electrophysiological signal acquisition device of this invention exhibits the most concentrated T / R distribution at all three vibration frequencies, with significantly reduced box width and a substantial decrease in the number of outliers, indicating that it has higher signal stability in dynamic environments.

[0125] The experimental results show that, under vibration conditions of 1Hz, 2Hz, and 5Hz, quantitative analysis of signal stability based on the interquartile range (IQR) of the T / R index in the box plot reveals the following: Under 1Hz vibration conditions, the IQR values ​​of the commercial BioPac system, the commercial BioPac system with digital filtering, and the device of this invention are 0.09085, 0.09308, and 0.01348, respectively. The IQR of the device of this invention is approximately 6.74 times lower than that of the unfiltered BioPac system and approximately 6.90 times lower than that of the BioPac system with digital filtering. Under 2Hz vibration conditions, the IQR values ​​of the three systems are 0.22801, 0.12940, and 0.05978, respectively. The IQR of the device of this invention is approximately 3.81 times lower than that of the unfiltered BioPac system and approximately 2.16 times lower than that of the BioPac system with digital filtering. Under 5Hz vibration conditions, the IQRs of the three systems were 0.05978, 0.12666, and 0.06804, respectively. The device of this invention performs comparably to the commercial BioPac system under these conditions, but still reduces IQR by approximately 1.86 times compared to the commercial BioPac system with digital filtering. These results fully demonstrate that this invention, based on skin ionization sensing technology, effectively improves the accuracy of electrophysiological signal acquisition in dynamic environments and significantly reduces motion artifact interference.

[0126] In summary, this invention not only optimizes the contact interface between the acquisition device and the skin, but also provides higher anti-interference capabilities in complex dynamic environments through innovative structural design of the composite sensing layer and material improvements in each functional layer, significantly improving the signal-to-noise ratio and stability of electrophysiological signals. By synergistically working the ionizing material in the composite sensing layer and the conductive electrodes in the electrode layer, the stability of the ion-skin interface is effectively enhanced, enabling active sensing and absorption of motion artifacts, ensuring high-quality signal acquisition, and improving the accuracy and stability of continuous monitoring of electrophysiological signals in complex environments.

[0127] Finally, it should be noted that although the embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, and not restrictive. Those skilled in the art, guided by this specification, can make many other forms without departing from the scope of protection of the claims of the present invention, and all of these are within the scope of protection of the present invention.

Claims

1. An electrophysiological signal acquisition device with motion artifact detection function, characterized in that, include: Flexible substrate layer; An electrode layer disposed on a substrate layer includes a patterned first conductive electrode, a second conductive electrode and a third conductive electrode. The composite sensing layer disposed on the surface of the electrode layer includes a first microstructure array, a second microstructure array, and a third microstructure array arranged in a coplanar staggered manner; the original signal acquisition unit constituting the first microstructure array, the ionization sensing positive electrode unit constituting the second microstructure array, and the ionization sensing negative electrode unit constituting the third microstructure array are all microstructures made of ion gel material, and adjacent microstructures are spaced apart from each other and electrically insulated. The original signal acquisition unit is connected to the first conductive electrode to form an electrophysiological signal acquisition channel, which is used to acquire a mixed signal containing electrophysiological signals and motion artifacts. The positive and negative ionization sensing sub-units are used in pairs and are respectively connected to the second and third conductive electrodes to form an ionization sensing channel, which is used to detect and output a compensation signal characterizing the capacitance change at the interface between the composite sensing layer and the skin; wherein, the compensation signal is used to eliminate motion artifacts in the mixed signal in order to extract the electrophysiological signal.

2. The electrophysiological signal acquisition device according to claim 1, characterized in that, In the composite sensing layer, a raw signal acquisition unit is adjacent to at least one pair of ion-sensing positive and ion-sensing negative units.

3. The electrophysiological signal acquisition device according to claim 1, characterized in that, In the composite sensing layer, all microstructures have the same or substantially the same geometry and dimensions.

4. The electrophysiological signal acquisition device according to claim 1, characterized in that, The material used to prepare the original signal acquisition unit has stretchable self-adhesive properties; the material used to prepare the positive and negative ion sensing poles has lower adhesion than the ion gel material used to prepare the original signal acquisition unit, but stronger mechanical properties.

5. The electrophysiological signal acquisition device according to claim 4, characterized in that, The original signal acquisition unit is prepared based on the PAAc-DES ion gel precursor solution; the ionization sensing positive electrode unit and the ionization sensing negative electrode unit are both prepared based on the precursor solution obtained by mixing the PAAc-DES ion gel precursor solution and fumed silica.

6. The electrophysiological signal acquisition device according to claim 5, characterized in that, The PAAc-DES ionogel precursor solution was obtained by mixing a deep eutectic solvent, acrylic acid, initiator, and crosslinking agent in mass percentages of 27.9%~29.9%, 69%~71%, 0.9%~1.1%, and 0.09%~0.11%, respectively; in the deep eutectic solvent, the molar ratio of choline chloride to hydrogen bond donor ethylene glycol was 1:1.9~2.

1. In the preparation of the precursor solutions for the ionization sensing positive and negative electrode units, the mass ratio of the PAAc-DES ion gel precursor solution to fumed silica is 9.5~10.5:

1.

7. The electrophysiological signal acquisition device according to claim 1, characterized in that, The first conductive electrode, the second conductive electrode, and the third conductive electrode are all made of silver paste or PEDOT:PSS conductive polymer.

8. The electrophysiological signal acquisition device according to any one of claims 1-7, characterized in that, The composite sensing layer also includes a fourth microstructure array arranged coplanarly and interleaved with the first, second, and third microstructure arrays; the damping unit constituting the fourth microstructure array is a microstructure made of ion gel material. The ion gel material used to prepare the damping unit has a network structure that combines viscoelasticity and energy dissipation properties.

9. The electrophysiological signal acquisition device according to claim 8, characterized in that, In the composite sensing layer, the smallest repeating unit in the overall microstructure array formed by the first microstructure array, the second microstructure array, the third microstructure array and the fourth microstructure array includes an original signal acquisition unit, a damping unit, and a pair of adjacent ionization sensing positive and ionization sensing negative units.

10. The electrophysiological signal acquisition device according to claim 8, characterized in that, In the composite sensing layer, the overall microstructure array formed by the first microstructure array, the second microstructure array, the third microstructure array and the fourth microstructure array is a hexagonal lattice, a square lattice, a rectangular lattice or an oblique lattice structure.

11. The electrophysiological signal acquisition device according to claim 8, characterized in that, The precursor solution for preparing the damping unit is obtained by mixing a deep eutectic solvent, acrylic acid, and polyethylene glycol in a mass ratio of 41-43 wt% : 27-29 wt% : 28-31 wt%; in the deep eutectic solvent, the molar ratio of choline chloride and hydrogen bond donor ethylene glycol is 1:1.9-2.

1.

12. The electrophysiological signal acquisition device according to claim 1, characterized in that, It also includes an adhesive layer disposed between the electrode layer and the substrate layer, through which the device is adhered to the skin; the material of the adhesive layer is modified PDMS; the modified PDMS is prepared by mixing a PDMS solution with ethoxylated polyethyleneimine at a mass ratio of 250:

1.

13. The electrophysiological signal acquisition device according to claim 1, characterized in that, The base layer is PDMS material; or, when the base layer is PI material, it further includes an encapsulation layer located outside the base layer; or, when the base layer is prepared using modified PDMS material doped with ethoxylated polyethyleneimine, it further includes an encapsulation layer located outside the base layer; the encapsulation layer is made of PDMS, PU, ​​or silicone rubber.

14. The electrophysiological signal acquisition device according to claim 12 or 13, characterized in that, It also includes a circuit board electrically connected to the first conductive electrode, the second conductive electrode and the third conductive electrode in the electrode layer; the circuit board is disposed adjacent to the substrate layer and is used for preprocessing the mixed signal and the compensation signal.

15. An electrophysiological signal acquisition system capable of removing motion artifacts, characterized in that, include: The electrophysiological signal acquisition device as described in any one of claims 1-14; The signal processing module is configured to process the mixed signal and compensation signal output by the electrophysiological signal acquisition device using a pre-stored neural network algorithm model constructed by combining 1D-CNN and bidirectional LSTM, and to remove motion artifacts in the mixed signal using the compensation signal to obtain the electrophysiological signal.

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