Interfacial viscosity light-controlled skin-type motion state monitoring hybrid electronic system

Abstract

This invention discloses a skin-based hybrid electronic system for motion monitoring with adjustable interfacial viscosity and light control. The system includes a circuit layer, a hydrogel interface layer, and an encapsulation layer. The circuit layer is encapsulated on the encapsulation layer, and the hydrogel interface layer is disposed at the bottom of the encapsulation layer. The hydrogel interface layer serves as a skin interface layer, adhering to the skin during use. The hydrogel in the interface layer is an adjustable viscous, light-controlled hydrogel. The circuit layer includes an interconnected front-end signal detection module and a back-end signal processing module. This system enables wearable and continuous monitoring of human motion parameters, offering excellent portability and comfort, improving the user experience, enhancing detection accuracy, and allowing for viscous adjustment and on-demand peeling without skin damage. This flexible hybrid system shows great promise in motion detection and other applications.

Description

Technical Field

[0001] This invention relates to the field of biomedical device technology, specifically to a hybrid electronic system for monitoring epidermal motion status with adjustable interfacial viscosity and light control. Background Technology

[0002] With the rapid development of competitive sports and the increasing intensity of international competition, technology-assisted sports have become an important research direction. Developing wearable devices with wireless transmission and real-time data analysis can effectively monitor athletes' training status, greatly promote the improvement of athletes' scientific training levels, and provide early warnings of the degree of injury to athletes. During training, the coordinated movements of various parts of the body generate corresponding physiological signals. By monitoring and analyzing these signals in real time, the training effect and physical condition of athletes can be quantitatively analyzed and objectively evaluated. Currently, most commercially available devices use rigid sensors for data acquisition, which have a modulus mismatch with the skin, resulting in large gaps that prevent conformal adhesion and inevitably lead to motion artifacts. Furthermore, they are not very comfortable to wear.

[0003] Compared to traditional rigid sensors, flexible sensing systems adhere more closely and comfortably to human skin, thus causing less stimulation to human tissue. Commonly used flexible electronic devices utilize photolithography and other microfabrication techniques to pattern electronic circuits, integrate functional chip components, and encapsulate soft materials, integrating multiple sensors into the smallest possible space to achieve hardware miniaturization and flexibility. Flexible electronic systems need to adhere to the surface of human skin and maintain conformal adhesion during human movement. Traditional adhesives or other sticky materials exhibit poor tolerance during movement and in sweaty environments, and can cause signal artifacts.

[0004] Flexible sensor systems, in order to acquire high-fidelity data, need to be as unaffected as possible by human movement and sweat. Therefore, the device must fit closely to the body, which can lead to skin pulling pain and device damage during peeling. Thus, developing a hydrogel interface with tunable viscosity holds great promise for applications such as motion detection. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a skin-type motion state monitoring hybrid electronic system with adjustable interfacial viscosity and light control, which addresses the above-mentioned defects in the existing technology. This system enables wearable and continuous detection of human motion state parameters, has good portability and comfort, improves the user's wearing experience, enhances detection accuracy, achieves viscosity control, and can be peeled off as needed without causing damage to the skin. This flexible hybrid system has broad prospects in motion detection and other fields.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] A hybrid electronic system for monitoring motion status on the skin with viscous light control is disclosed, comprising a circuit layer, a hydrogel interface layer, and an encapsulation layer. The circuit layer is encapsulated on the encapsulation layer, and the hydrogel interface layer is disposed at the bottom of the encapsulation layer. The hydrogel interface layer serves as a skin interface layer and adheres to the skin during use. The hydrogel in the hydrogel interface layer is a viscous light control adjustable hydrogel. The circuit layer includes a front-end signal detection module and a back-end signal processing module that are interconnected.

[0008] According to the above technical solution, the hydrogel interface layer includes an electrode area hydrogel and a sub-adhesion area hydrogel. The electrode area hydrogel is connected to the circuit layer. The electrode area hydrogel contains conductive ions and serves as an epidermal electrode to provide an ion channel for ECG acquisition. The sub-adhesion area hydrogel does not contain conductive ions and serves as an auxiliary adhesive to provide reliable adhesion for the overall system.

[0009] Both the electrode region hydrogel and the sub-adhesion region hydrogel are viscous photosensitive tunable hydrogels. The viscosity of the viscous photosensitive tunable hydrogel changes under different wavelengths of ultraviolet irradiation, which allows the epidermal electrode to maintain good contact with human skin. At the same time, it facilitates the adhesion and removal of the motion state monitoring hybrid electronic system, and human electrocardiogram signals are collected through the viscous photosensitive hydrogel epidermal electrode in the hydrogel interface layer.

[0010] According to the above technical solution, the front-end signal detection module includes an ECG monitoring module, a triaxial accelerometer, and a microfluidic sensor, and the back-end signal processing module includes a main control chip module, a power supply module, a signal processing module, a clock crystal oscillator module, a program programming module, and a Bluetooth radio frequency module. The main control chip module is connected to the ECG monitoring module, the triaxial accelerometer, and the microfluidic sensor through the signal processing module, and the main control chip module is connected to the power supply module, the signal processing module, the clock crystal oscillator module, the program programming module, and the Bluetooth radio frequency module, respectively.

[0011] According to the above technical solution, the encapsulation layer is made of polydimethylsiloxane (PDMS);

[0012] The circuit layer includes a printed circuit board (FPCB) with a flexible material substrate, and the front-end signal detection module and the back-end signal processing module are disposed on the printed circuit board with a flexible material substrate.

[0013] According to the above technical solution, the electrode area hydrogel epidermal electrode is disc-shaped, and the sub-adhesion area hydrogel is distributed in a ring around the center of the electrode area hydrogel, with annular grooves in the sub-adhesion area hydrogel.

[0014] According to the above technical solution, the viscous light-controlled adjustable hydrogel contains coumarin.

[0015] According to the above technical solution, the viscous light-controlled tunable hydrogel is a porous hydrogel.

[0016] According to the above technical solution, the viscous, light-controlled tunable hydrogel is composed of polyaspartic acid-coumarin (PASP-BAC), carboxymethyl cellulose-dopamine (CMC-DA), and acrylic acid (AAC). The hydrogel in the electrode region also contains lithium ions (Li). + ).

[0017] According to the above technical solution, the preparation method of the viscous light-controlled tunable hydrogel includes the following steps:

[0018] Step 1: Dissolve 5-10 wt% acrylic acid (AAC) monomer in deionized water, then add 0.1 wt% ammonium persulfate (APS) and 0.02 wt% N,N'-methylenebisacrylamide (MBAA) as crosslinking agent and initiator;

[0019] Step 2: Add 5%-15wt% polyaspartic acid-coumarin (PASP-BAC) monomer and 2-5wt% carboxymethyl cellulose-dopamine (CMC-DA) monomer to the above solution to obtain solution A. Take a portion of solution A and add 0.1wt% lithium chloride (LiCl) and 0.05wt% methpropylene ethyl sulfobetaine (SPE) monomer to obtain solution B.

[0020] Step 3: The aforementioned solutions A and B are poured into a patterned reaction vessel with a thickness of 1-3 mm according to the layout of the electrode region and the sub-adhesion region, and copolymerized in the dark to synthesize the hydrogel interface.

[0021] According to the above technical solution, the preparation method for each 3 mmol of polyaspartic acid-coumarin includes the following steps:

[0022] Step 1.1: Dissolve 5 mmol-15 mmol of polyaspartic acid (PASP) in dimethyl sulfoxide (DMSO), and purge the solution with nitrogen gas at a constant rate for 30 min to complete degassing and form a buffer solution;

[0023] Step 1.2: Add 3 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) and 3 mmol of 1-hydroxybenzotriazole (HOBt) to the buffer solution, mix and stir magnetically for half an hour under nitrogen protection, and degas for 15 minutes.

[0024] Step 1.3: Add 3 mmol of 7-amino-4-methylcoumarin (AMC), seal and stir for 6 hours, then dialyze the resulting solution for 48 hours, and freeze-dry in a lyophilizer to obtain polyaspartic acid-coumarin PASP-AMC powder, which is kept dry before use.

[0025] The present invention has the following beneficial effects:

[0026] This invention utilizes a viscous, light-controlled, adjustable hydrogel that is directly adhered to the skin, enabling wearable and continuous monitoring of human motion parameters. It offers excellent portability and comfort, improves the user experience, enhances detection accuracy, allows for viscous adjustment, and can be peeled off as needed without damaging the skin. This flexible hybrid system has broad prospects in motion detection and other fields. Attached Figure Description

[0027] Figure 1 This is a circuit diagram of the skin-type motion state monitoring hybrid electronic system with adjustable interfacial viscosity and light control in an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of the structure of the skin-type motion state monitoring hybrid electronic system with adjustable interfacial viscosity and light control in an embodiment of the present invention;

[0029] Figure 3 This is an exploded view of the skin-type motion state monitoring hybrid electronic system with adjustable interfacial viscosity and light control in an embodiment of the present invention.

[0030] Figure 4 This is a flowchart illustrating the preparation process of the viscous, light-controlled, tunable hydrogel in this embodiment of the invention.

[0031] Figure 5 This is a schematic diagram illustrating the principle of adjustable light-controlled viscosity of coumarin hydrogel in an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the coumarin hydrogel perforation mold structure in an embodiment of the present invention;

[0033] In the diagram, 1 is the polydimethylsiloxane (PDMS) encapsulation layer, 2 is the FPCB circuit board, 3 is the switching element, 4 is the 3V button battery, 5 is the AD8232 ECG front-end chip, 6 is the ADXL345 accelerometer, 7 is the Bluetooth antenna, 8 is the microfluidic sensor, 9 is the CC2640R2F main control chip, 10 is the coumarin hydrogel interface layer electrode area, 11 is the coumarin hydrogel interface sub-adhesion area, 12 is the power supply module, 13 is the front-end signal detection module, 14 is the back-end signal processing output module, 15 is the 3.3V boost power supply module, 16 is the clock management, 17 is the Bluetooth SoC, 18 is the program burning, 19 is the clock circuit, 20 is the computer terminal, 21 is the high-pass and low-pass filter, and 22 is the A PP terminal, 23 is dimethyl sulfoxide, 24 is polyaspartic acid, 25 is EDC, 26 is HOBt, 27 is 7-amino-4-methylcoumarin, 28 is PASP-BMC, 29 is deionized water, 30 is 2-(N-morpholino)ethanesulfonic acid, 31 is sodium chloride, 32 is sodium hydroxide, 33 is N-hydroxysuccinimide, 34 is carboxymethyl cellulose, 35 is dopamine, 36 is CMC-DA, 37 is ammonium persulfate, 38 is acrylic acid, 39 is N,N'-methylenebisacrylamide, 40 is lithium chloride, 41 is methyl propylene ethyl sulfobetaine, 42 is a four-cornered fan-shaped slot bottom plate, 43 is an inner fan-shaped ring, 44 is a glass capillary, 45 is a fan-shaped column, and 46 is a square cover plate. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] Reference Figures 1-6 As shown, an embodiment of the present invention provides a skin-type motion monitoring hybrid electronic system with adjustable viscous light control, comprising a circuit layer, a hydrogel interface layer, and an encapsulation layer. The circuit layer is encapsulated on the encapsulation layer, and the hydrogel interface layer is disposed at the bottom of the encapsulation layer. The hydrogel interface layer serves as a skin interface layer, adhering to the skin during use. The hydrogel in the hydrogel interface layer is a viscous, light-controlled adjustable hydrogel. This makes the skin-type motion monitoring hybrid electronic system a flexible electronic system that can be attached to human skin. The circuit layer includes a front-end signal detection module and a back-end signal processing module that are interconnected. The front-end signal detection module can collect motion parameters such as speed, acceleration, and motion posture signals. The back-end signal processing output module is connected to the front-end motion detection circuit, receives the collected detection signals, and can filter and amplify the electrocardiogram information and motion parameters before wirelessly transmitting them to an external smart terminal APP via Bluetooth module to achieve data visualization.

[0036] Furthermore, the hydrogel interface layer includes an electrode region hydrogel and a sub-adhesion region hydrogel. The electrode region hydrogel is connected to the ECG monitoring module of the circuit layer. The electrode region hydrogel contains conductive ions and acts as an epidermal electrode to provide an ion channel for ECG acquisition. The sub-adhesion region hydrogel does not contain conductive ions and acts as an auxiliary adhesive to provide reliable adhesion for the overall system. As a flexible composite material formed by cross-linking of a polymer network, hydrogel has good ductility and stretchability. At the same time, by assembling conductive ions or adhesive functional monomers into the polymer network, it can improve other properties such as conductivity and adhesion, making it a good material for optimizing the flexible electrode interface.

[0037] Both the electrode region hydrogel and the sub-adhesion region hydrogel are viscous photosensitive tunable hydrogels. The viscosity of the viscous photosensitive tunable hydrogel changes under different wavelengths of ultraviolet irradiation, which allows the epidermal electrode to maintain good contact with human skin. At the same time, it facilitates the adhesion and removal of the motion state monitoring hybrid electronic system, and human electrocardiogram signals are collected through the viscous photosensitive hydrogel epidermal electrode in the hydrogel interface layer.

[0038] Furthermore, the front-end signal detection module includes an ECG monitoring module, a triaxial accelerometer, a main circuit control chip, and a microfluidic sensor. The back-end signal processing module includes a main control chip module, a power supply module, a signal processing module, a clock crystal oscillator module, a programming module, and a Bluetooth RF module. The main control chip module is connected to the ECG monitoring module, triaxial accelerometer, and microfluidic sensor via the main circuit control chip and the signal processing module. The main control chip module is also connected to the power supply module, signal processing module, clock crystal oscillator module, programming module, and Bluetooth RF module. The entire system is encapsulated in flexible materials. The physiological signals collected by the signal processing module are filtered, amplified, and transmitted to the main control chip module for processing. The signals are then sent to the mobile terminal in real time via the Bluetooth module and saved as files, enabling data visualization.

[0039] Furthermore, the front-end signal detection module is directly connected to the back-end signal processing module via a connecting cable. The back-end processing output module provides a stable operating voltage and ground potential to the front-end status detection module via the connecting cable, and the front-end status detection module also directly transmits the collected physiological signal data to the back-end signal processing module via the connecting cable; the back-end signal processing module is connected to a mobile phone via a Bluetooth radio frequency module, and connects to a mobile terminal human-computer interaction App.

[0040] The main control chip of the front-end signal detection module is CC2640R2F, and the main control chip of the back-end signal detection module is CC2640R2F. The power supply module consists of a CR2032 button battery power supply module and a TPS61070 boost power supply module. The BOOST boost power management chip regulates the 3V output voltage of the button battery to 3.3V, providing a stable 3.3V voltage source for the overall circuit. The main control chip module consists of the CC2640R2F chip, its associated crystal oscillator, and a patch ceramic antenna, which has the characteristics of being economical, efficient, and low-power. The ECG monitoring module consists of AD8232 and its peripheral devices, and is connected to three ECG electrodes (i.e., three electrode areas of hydrogel epidermal electrodes) through related circuits to realize the task of acquiring and transmitting EEG signals. The three-axis acceleration module consists of ADXL345 and its peripheral devices.

[0041] The CC2640R2F main control chip module controls the operation of the front-end status detection module, analyzes and processes the physiological signals collected by the front-end status detection module, and interacts with the mobile terminal's human-machine interface app via the Bluetooth radio frequency module. The program programming module is used to write the programs and protocols required by the back-end signal processing output module into the CC2640R2F core processing module. The clock crystal oscillator module assists the normal operation of the CC2640R2F core processing module, employing two passive crystal resonators at 24MHz and 32.768kHz. The Bluetooth radio frequency module uses a differential antenna to ensure excellent data communication; the Bluetooth radio frequency antenna has an impedance of 50Ω.

[0042] Furthermore, the encapsulation layer is made of flexible polydimethylsiloxane (PDMS). By using flexible polydimethylsiloxane (PDMS) material and controlling the thickness to ensure low modulus, sweat can be prevented from seeping into the circuit and causing circuit failure. At the same time, it can also serve as a base for hydrogel. By encapsulating with polydimethylsiloxane (PDMS), an epidermal-attached motion monitoring system is obtained.

[0043] The circuit layer includes a printed circuit board (FPCB) with a flexible material substrate, and the front-end signal detection module and the back-end signal processing module are disposed on the printed circuit board with a flexible material substrate.

[0044] Furthermore, its front-end signal detection module consists of an electrocardiogram monitoring module, a microfluidic sensor, and a triaxial accelerometer. The microfluidic sensor is composed of three annular thermal bands. The three isolated thermal films distributed in the circular area can measure the surface flow velocity and direction angle by detecting the flow-induced temperature distribution, thereby realizing the detection of human motion parameters. The thermal adhesive film can be used as both a Joule heater and a thermometer. The microfluidic sensor obtains motion parameters by detecting the motion-sensing surface flow and uses a Kalman filter to achieve sensor data fusion, which can effectively detect the speed and posture of human movement.

[0045] Furthermore, the hydrogel epidermal electrode in the electrode area is disc-shaped, which has a positioning effect when attached, making the acquisition of ECG signals more accurate. The hydrogel in the sub-adhesion area is distributed in a ring around the hydrogel in the electrode area. The hydrogel in the sub-adhesion area has annular grooves with a height-to-width ratio of 3, which plays a role in sweating and improves the stability and service life of the system.

[0046] Furthermore, the viscous, light-controlled, adjustable hydrogel epidermal electrode is not only suitable for detecting electrocardiogram signals in this application, but can also be extended to detect other physiological electrical signals (electromyography, electroencephalography, etc.).

[0047] Furthermore, there are three disc-shaped hydrogel electrodes, corresponding to positions V2, V3, and V4 in a 12-lead electrocardiogram.

[0048] Furthermore, the viscous, light-controlled tunable hydrogel includes coumarin, forming a coumarin hydrogel. This coumarin hydrogel exhibits excellent adhesion to biological tissues, and its interfacial viscosity can be further regulated based on the photoreversal reaction of coumarin. By irradiating the hydrogel with 365nm ultraviolet light, the cross-linking density increases, fluidity decreases, modulus increases, and shape retention with skin deteriorates. Simultaneously, the number of free hydroquinone groups decreases, weakening the interfacial binding strength with the skin, ultimately leading to a decrease in viscosity. This reduces the hydrogel's viscosity, making it easier to remove the device. When irradiated with 254nm ultraviolet light, depolymerization occurs, resulting in a decrease in the final cross-linking strength of the hydrogel, a decrease in modulus, enhanced shape retention, increased fluidity of the hydrogel network, and restored viscosity. This achieves viscous regulation, allowing for on-demand peeling without damaging the skin or device. This viscous, light-controlled tunable hydrogel inherits the stretchable and adhesive characteristics of traditional hydrogels while overcoming their drawback of uncontrollable viscosity, expanding the application scenarios of hydrogels.

[0049] Furthermore, the viscous, light-controlled, tunable hydrogel is a porous hydrogel. By preparing the porous hydrogel using a customized mold, the irradiation area and penetration depth of ultraviolet light are increased, accelerating the photodimerization and photolysis reactions of coumarin, and thus accelerating the rate of viscosity change under different ultraviolet light irradiations. Under 365 nm ultraviolet light irradiation, due to the relatively small molar absorption coefficient of coumarin monomers, the photodimerization of coumarin groups occurs rapidly, cross-linking to form a dense ionic gel network. However, under 254 nm ultraviolet light irradiation, due to the larger molar absorption coefficient of coumarin dimers, the photolysis reaction of coumarin dimers starts from the sample surface closest to the ultraviolet light source and then gradually slows down to the bottom of the sample. Therefore, the photoinduced gel-sol transition process under 254 nm ultraviolet light takes longer than the photoinduced sol-gel transition process under 365 nm ultraviolet light. Preparing porous structures on the surface of hydrogels can greatly increase the irradiation area and penetration depth of ultraviolet light. Furthermore, the hollow glass tubes facilitate the all-round reflection of ultraviolet light, which is beneficial for accelerating the photodimerization and photodegradation reactions of coumarin, with the greatest benefit being for photodegradation.

[0050] Furthermore, the perforation mold structure design for the hydrogel electrode is prepared by laser cutting. The mold is divided into an upper mold and a lower mold, and their relative positions are determined by a slot. The upper mold has small round holes with a uniform density and a diameter of 0.3 mm. A glass capillary tube with a length of 4 mm and an outer diameter of 0.3 mm is inserted into each small round hole and sealed at the insertion end, and fixed with glue. The glass capillary tube plays the role of cutting the hydrogel electrode, thereby preparing a porous hydrogel.

[0051] A laser cutter was used to cut out a base plate with four fan-shaped grooves at the four corners of a 3mm thick acrylic sheet. The two plates were then glued together at the overlapping points of the fan-shaped arcs to create the lower half of the mold capable of holding the solution. A square plate was cut out of a 2mm thick acrylic sheet using the same laser cutter. Small, uniformly spaced holes, each 0.3mm in diameter, were drilled within a radius equal to the size of the grooves in the circular ring. A 4mm long, 0.3mm outer diameter hole was then inserted into each of these holes. A glass capillary tube with a sealed insertion end is fixed with glue. Four sector-shaped posts with insertable slots are then glued to the four corners of a square plate to facilitate positioning between the cover plate and the bottom mold and to ensure uniform formation of pores on the hydrogel surface. This completes the preparation of the upper mold. The prepared hydrogel is cut into the shape of the lower mold and placed inside. The relative positions of the glass tube and hydrogel are determined by the sector-shaped post slots in the upper mold and the sector-shaped grooves in the lower mold. The upper mold is pressed until it fits snugly against the lower mold, at which point the glass tube cuts the hydrogel. The upper mold is then lifted, and the hydrogel in the lower mold is removed. It is rinsed with sufficient deionized water to remove surface burrs, and then further dried with paper to obtain the perforated hydrogel.

[0052] Furthermore, the viscous, light-controlled tunable hydrogel is composed of polyaspartic acid-coumarin (PASP-BAC), carboxymethyl cellulose-dopamine (CMC-DA), and acrylic acid (AAC). In addition to the above components, the electrode region hydrogel also contains lithium ions (Li). + ).

[0053] Furthermore, carboxymethyl cellulose-dopamine (CMC-DA) is prepared by degassing, magnetic stirring, and freeze-drying in a biological buffer solution of morpholine ethanesulfonic acid (MES) using carboxymethyl cellulose as a long-chain polymer, dopamine molecules as functional groups, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as carboxyl activators. The hydrogel is prepared by light-shielded copolymerization of polyaspartic acid-coumarin (PASP-BAC) monomer, carboxymethyl cellulose-dopamine (CMC-DA) monomer, acrylic acid (AAC) monomer, ammonium persulfate (APS) as an oxidant, and N,N'-methylenebisacrylamide monomer (MBAA) as a crosslinking agent.

[0054] Furthermore, the preparation method of the aforementioned viscous, light-controlled, tunable hydrogel includes the following steps:

[0055] Step 1: Dissolve 5-10 wt% acrylic acid (AAC) monomer in deionized water, then add 0.1 wt% ammonium persulfate (APS) and 0.02 wt% N,N'-methylenebisacrylamide (MBAA) as crosslinking agent and initiator;

[0056] Step 2: Add 5%-15wt% polyaspartic acid-coumarin (PASP-BAC) monomer and 2-5wt% carboxymethyl cellulose-dopamine (CMC-DA) monomer to the above solution to obtain solution A. Take a portion of solution A and add 0.1wt% lithium chloride (LiCl) and 0.05wt% methpropylene ethyl sulfobetaine (SPE) monomer to obtain solution B.

[0057] Step 3: The aforementioned solutions A and B are poured into a patterned reaction vessel with a thickness of 1-3 mm according to the layout of the electrode region and the sub-adhesion region, and copolymerized in the dark to synthesize the hydrogel interface.

[0058] Furthermore, the preparation method of the polyaspartic acid-coumarin includes the following steps:

[0059] Step 1.1: Dissolve 5 mmol-15 mmol of polyaspartic acid (PASP) in more than 20 ml of dimethyl sulfoxide (DMSO), and purge the solution with nitrogen gas at a constant rate for 30 min to complete degassing and form a buffer solution.

[0060] Step 1.2: Add 3 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) and 3 mmol of 1-hydroxybenzotriazole (HOBt) to the buffer solution, mix and stir magnetically for half an hour under nitrogen protection, and degas for 15 minutes.

[0061] Step 1.3: Add 3 mmol of 7-amino-4-methylcoumarin (AMC), seal and stir for 6 hours, then dialyze the resulting solution for 48 hours, and freeze-dry in a lyophilizer to obtain polyaspartic acid-coumarin PASP-AMC powder, which is kept dry before use.

[0062] The preparation method of carboxymethyl cellulose-dopamine includes the following steps:

[0063] Step 2.1: Dissolve 2-(N-morpholino)ethanesulfonic acid (MES) and sodium chloride in deionized water, and adjust the pH to 5.4 by adding sodium hydroxide dropwise using a pH meter (Mettler-Toledo seven-level series table) to obtain MES buffer solution;

[0064] Step 2.2: Dissolve 5 mmol-15 mmol of carboxymethyl cellulose (CMC) in MES buffer, and purge the buffer with nitrogen gas at a constant rate for 30 min to complete degassing;

[0065] Step 2.3: Add 3 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and 3 mmol of N-hydroxysuccinimide (NHS) to the buffer solution, mix and stir magnetically for half an hour under nitrogen protection, and degas for 15 minutes.

[0066] Step 2.4: Add 3 mmol of dopamine (DA), seal and stir for 6 hours, then dialyze the resulting solution for 48 hours, and freeze-dry in a lyophilizer to obtain CMC-DA. This powder is kept dry until used.

[0067] The materials used in the preparation process include the biological buffer MES30, carboxymethyl cellulose (CMC)34, 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC)25, N-hydroxythiosuccinimide (NHS)33, polyaspartic acid-coumarin (PASP-BAC)28 monomer, carboxymethyl cellulose-dopamine (CMC-DA)36 monomer, acrylic acid (AAC)38 monomer, ammonium persulfate (APS)37 oxidant, and crosslinking agent. The mass fractions of N,N'-methylenebisacrylamide monomer (MBAA) 39, polyaspartic acid-coumarin (PASP-BAC) 28 monomer, carboxymethyl cellulose-dopamine (CMC-DA) 36 monomer, acrylic acid (AAC) 38 monomer, ammonium persulfate (APS) 37, and N,N'-methylenebisacrylamide monomer (MBAA) 39 are 5-15 wt%, 2-5 wt%, 5-10 wt%, 0.1 wt%, and 0.02 wt%, respectively.

[0068] Further preferably, the amount of carboxymethyl cellulose (CMC) 34 is 5-15 mmol, and the amounts of EDC 25, NHS 33, and DA 35 are all 3 mmol; the stirring operation uses a glass rod for stirring for 30 min; the ultrasonic oscillation uses a 100W ultrasonic machine at a temperature of 25 degrees Celsius for 30 min; the degassing operation involves uniformly introducing nitrogen gas into the container containing the target solution for 30 min to obtain a completely degassed target solution.

[0069] Working principle of the invention:

[0070] See Figure 1 This invention provides a hybrid electronic system for motion monitoring, characterized by a front-end signal detection module 13, a back-end signal processing and output module 14, and a mobile terminal App 22. This skin-adhesive, adhesive, light-controlled, and adjustable hybrid electronic system for motion monitoring can monitor the electrocardiogram (ECG) signals and motion parameters of the subject and communicate with the mobile terminal App 22 via a Bluetooth antenna 7.

[0071] The front-end signal detection module 13 includes an ECG front-end module 5, a triaxial accelerometer 6, and a microfluidic sensor 8, used to acquire ECG information and motion parameters. The back-end signal processing output module 14 includes an MCU main control module 9, a power supply module 12, a clock circuit 19, and a Bluetooth antenna 7. The back-end signal processing output module 14 receives the ECG signal and motion parameters acquired and filtered by the front-end signal detection module 13 through an ADC converter, and then inputs them to the MCU main control module 9. The power supply module 12 supplies power to the entire sensing system, including the front-end signal detection module 13 and the back-end signal processing output module 14. The boost module 15 adjusts the 3V output voltage of the power supply module to 3.3V, providing a stable 3.3V voltage source for the overall circuit. The Bluetooth SoC 17 of the MCU main control module 9 transmits the processed data to the APP terminal 22 through the Bluetooth antenna 7.

[0072] The main control chip module 9 is a CC2640R2F MCU main control chip, which integrates a clock management module 16, a Bluetooth SoC 17, and a programming module 18. The X32KQ1, X32KQ2, X24MP, and X24MN ports of the MCU main control chip are connected to an external clock crystal module 19, which includes a 32.768kHz clock circuit and a 24kHz clock circuit. The RFP and RFN ports of the MCU main control chip 9 are connected to the signal input terminals of the Bluetooth antenna 7, mainly for transmitting signals; information storage and transmission control are implemented by the internal Bluetooth SoC 17. The TMSC, TCKC, TDI, and TDO ports of the MCU main control chip 9 are connected to the signal input terminals of the programming module 18.

[0073] The ECG front-end module 5 uses an AD8232 chip, which has a built-in high-pass and low-pass filter 21. The high-pass and low-pass filter 21 includes a double-pole high-pass filter with a cutoff frequency of 0.3Hz and a double-pole low-pass filter with a cutoff frequency of 37Hz, filtering and reducing noise in the input ECG signal. The ECG electrodes 10 are connected to the interface of the AD8232 chip to transmit ECG signals. The LDO+, LDO-, SDN, and MCUAD ports of the AD8232 chip are connected to the corresponding ports of the CC2640R2F MCU main control module 9. The LDO+ and LDO- ports are used for lead detachment detection, the SDN port is used for switch control, and the MCUAD port is an A / D port used for ECG data transmission.

[0074] See Figure 2This invention provides a schematic diagram of a hybrid electronic system for monitoring skin-like motion. The substrate 2 of the hybrid electronic system for monitoring skin-like motion utilizes an FPCB board to achieve substrate flexibility. All components and integrated circuits of the electronic system are concentrated in the circuit area, including a switching element 3, a 3V button battery 4, an AD chip 5, a triaxial accelerometer 6, a ceramic Bluetooth antenna 7, a microfluidic sensor 8, a main control chip 9, etc. Coumarin hydrogel is attached to three circular areas 8 on the back of the substrate. The central part of each hydrogel contains conductive ions, serving as an ion channel for the skin electrode sensing interface. The surrounding area is composed of coumarin hydrogel with adjustable interfacial viscosity, enhancing adhesion and maintaining a consistent fit during human movement. When removal is required, the viscosity is reduced by irradiating with ultraviolet light of a fixed wavelength, making it easier to peel off. Grooves 8 are designed on the substrate at the adhesion points of the hydrogel to facilitate timely drainage of sweat, improving the stability and lifespan of the electronic system.

[0075] In summary, 1. The skin-type motion state monitoring hybrid electronic system provided by this invention is a wearable flexible detection system that, while achieving overall circuit functionality, possesses superior tensile and deformation capabilities. This detection system is wearable and can continuously detect human electrocardiogram signals and motion parameters, transmitting them to a mobile terminal via Bluetooth and generating files for data visualization. This skin-type system offers excellent portability and comfort, improving the user's wearing experience.

[0076] 2. The motion monitoring system preferably uses a CC2640R2F core processor, an AD8232 chip for the ECG acquisition front-end module, an ADXL345 for the triaxial accelerometer, and a microfluidic sensor that uses a non-integral velocity monitoring method to acquire the human body's motion speed and posture. Based on the above chip selection, the project circuit is designed in Altium Designer, and the corresponding FPCB flexible system device is fabricated. To prevent sweat from seeping into the circuit and causing circuit failure, polydimethylsiloxane (PDMS) is used for encapsulation. These preferred solutions ensure that the functional circuit has a high degree of integration and as few components as possible while meeting the intended functions, and also reduce the impact of system stretching deformation on the circuit.

[0077] 3. The hydrogel interface that binds to the skin has good self-adhesion, which effectively enables the acquisition electrode to maintain a stable conformal contact with the skin for a long time, reduces the gap between the electrode and the skin, and resists the influence of human movement and sweat. This helps to reduce interference from external factors, reduce signal attenuation, and improve the accuracy of measurement.

[0078] 4. The hydrogel interface differs from traditional hydrogel materials. It utilizes dopamine molecules grafted onto long-chain polymers as functional groups, and further modulates the interfacial viscosity based on the coumarin photoreversal reaction. When the hydrogel interface is irradiated with 365nm light dimer, the hydrogel crosslinking density increases, the fluidity decreases, the modulus increases, the conformability with the skin decreases, and the bonding strength with the skin interface decreases, ultimately leading to a decrease in viscosity, making it easier to remove the device. When irradiated with 256nm light, depolymerization occurs, resulting in a decrease in the final hydrogel crosslinking strength, a decrease in modulus, enhanced conformability, increased fluidity of the hydrogel network, and restoration of viscosity, ensuring conformal adhesion to the skin during normal operation. This achieves light-controlled adjustable viscosity of the hydrogel interface.

[0079] 5. The coumarin hydrogel is prepared using polyaspartic acid-coumarin (PASP-BAC), carboxymethyl cellulose-dopamine (CMC-DA), and acrylic acid (AAC) as main raw materials. Carboxymethyl cellulose serves as the long-chain polymer, dopamine molecules as the functional groups, EDC and NHS as carboxyl activators, MES as a biological buffer, and ammonium persulfate (APS) and N,N'-methylenebisacrylamide monomer (MBAA) as crosslinking agents and initiators. The preparation process involves degassing, stirring, freeze-drying, dialysis, and light-protected copolymerization. The preparation process is simple and easy to operate, with low production costs, enabling the fabrication of large-area human epidermal physiological electrodes, and is also easy for mass production.

[0080] The above are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent changes made in accordance with the claims of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A hybrid electronic system for monitoring skin-like motion states with adjustable interfacial viscosity and light control, characterized in that, It includes a circuit layer, a hydrogel interface layer and an encapsulation layer. The circuit layer is encapsulated on the encapsulation layer. The hydrogel interface layer is arranged at the bottom of the encapsulation layer. The hydrogel interface layer serves as a skin interface layer and adheres to the skin during use. The hydrogel in the hydrogel interface layer is a viscous, light-controlled, adjustable hydrogel. The circuit layer includes a front-end signal detection module and a back-end signal processing module that are interconnected. The hydrogel interface layer includes an electrode region hydrogel and a sub-adhesion region hydrogel. The electrode region hydrogel is connected to the circuit layer and contains conductive ions, serving as an epidermal electrode to provide an ion channel for ECG acquisition. The sub-adhesion region hydrogel does not contain conductive ions and serves as an auxiliary adhesive to provide reliable adhesion for the overall system. Both the hydrogel in the electrode region and the hydrogel in the sub-adhesion region are viscous photosensitive tunable hydrogels. The viscosity of the viscous photosensitive tunable hydrogel changes under different wavelengths of ultraviolet light irradiation, which allows the epidermal electrode to maintain good contact with human skin. At the same time, it facilitates the adhesion and removal of the motion state monitoring hybrid electronic system, and human electrocardiogram signals are collected through the viscous tunable hydrogel epidermal electrode in the hydrogel interface layer. The viscous, light-controlled tunable hydrogel is composed of polyaspartic acid-coumarin, carboxymethyl cellulose-dopamine, and acrylic acid, and the hydrogel in the electrode region also contains lithium ions.

2. The interfacial viscosity light-controlled adjustable skin-type motion state monitoring hybrid electronic system according to claim 1, characterized in that, The front-end signal detection module includes an ECG monitoring module, a triaxial accelerometer, and a microfluidic sensor. The back-end signal processing module includes a main control chip module, a power supply module, a signal processing module, a clock crystal oscillator module, a program programming module, and a Bluetooth radio frequency module. The main control chip module is connected to the ECG monitoring module, the triaxial accelerometer, and the microfluidic sensor through the signal processing module. The main control chip module is also connected to the power supply module, the signal processing module, the clock crystal oscillator module, the program programming module, and the Bluetooth radio frequency module.

3. The interfacial viscosity light-controlled adjustable skin-type motion state monitoring hybrid electronic system according to claim 1, characterized in that, The encapsulation layer is made of polydimethylsiloxane; The circuit layer includes a printed circuit board based on a flexible material, with the front-end signal detection module and the back-end signal processing module disposed on the printed circuit board based on the flexible material.

4. The interfacial viscosity light-controlled adjustable skin-type motion state monitoring hybrid electronic system according to claim 1, characterized in that, The electrode area hydrogel epidermis electrode is disc-shaped, and the sub-adhesion area hydrogel is distributed in a ring around the center of the electrode area hydrogel, with annular grooves in the sub-adhesion area hydrogel.

5. The interfacial viscosity light-controlled adjustable skin-type motion state monitoring hybrid electronic system according to claim 1, characterized in that, The viscous light-controlled tunable hydrogel is a porous hydrogel.

6. The interfacial viscosity light-controlled adjustable skin-type motion state monitoring hybrid electronic system according to claim 1, characterized in that, The preparation method of the aforementioned viscous, light-controlled, tunable hydrogel includes the following steps: Step 1: Dissolve 5-10 wt% acrylic acid monomer in deionized water, then add 0.1 wt% ammonium persulfate and 0.02 wt% N,N'-methylenebisacrylamide as crosslinking agent and initiator; Step 2: Add 5-15 wt% polyaspartic acid-coumarin monomer and 2-5 wt% carboxymethyl cellulose-dopamine monomer to the above solution to obtain solution A. Take a portion of solution A and add 0.1 wt% lithium chloride and 0.05 wt% methpropylene ethyl sulfobetaine monomer to obtain solution B. Step 3: The aforementioned solutions A and B are poured into a patterned reaction vessel with a thickness of 1-3 mm according to the layout of the electrode region and the sub-adhesion region, and copolymerized in the dark to synthesize the hydrogel interface.

7. The interfacial viscosity light-controlled adjustable skin-type motion state monitoring hybrid electronic system according to claim 1, characterized in that, The preparation method for each 3 mmol of polyaspartic-coumarin includes the following steps: Step 1.1: Dissolve 5 mmol-15 mmol of polyaspartic acid in more than 20 ml of dimethyl sulfoxide solution, and introduce nitrogen gas into the solution at a constant rate for 30 min to complete degassing and form a buffer solution; Step 1.2: Add 3 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 3 mmol of 1-hydroxybenzotriazole to the buffer solution, mix and stir magnetically for half an hour under nitrogen protection, and degas for 15 minutes. Step 1.3: Add 3 mmol of 7-amino-4-methylcoumarin, seal and stir for 6 hours, then dialyze the resulting solution for 48 hours, and freeze-dry in a lyophilizer to obtain polyaspartic acid-coumarin powder, which is kept dry before use.

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