Preparation method and sensor of hydrogel film sensor for muscle force prediction

Abstract

The present application discloses a method for preparing a hydrogel film sensor and a sensor for muscle force prediction. The method includes selecting the material ratio of the hydrogel precursor according to the sensitivity parameter and mechanical stress parameter of the sensor; preparing a hydrogel film, and arranging electrodes symmetrically on the left and right sides of the length direction of the hydrogel film to form a hydrogel film sensing structure; obtaining the change in the resistance value of the hydrogel film sensing structure, and forming a one-to-one correspondence with the strain value of the sensor for calibration; performing a strength test on the target muscle group, measuring the resistance value of the hydrogel film sensing structure tightly attached to the skin surface, and correlating the strength test results with the resistance change of the hydrogel film sensing structure to form a muscle force prediction model. The scheme of the present invention can greatly improve the accuracy of muscle force testing.

Description

Technical Field

[0001] The present invention generally relates to the field of flexible sensors, and more specifically, to a method for preparing a hydrogel film sensor for muscle force prediction and a sensor. Background Art

[0002] As a core technology in rehabilitation medicine, sports training and biomechanics research, muscle strength testing provides a scientific basis for patients' rehabilitation process, optimizes personalized exercise plans, and prevents sports injuries by accurately monitoring and quantifying muscle strength, thereby significantly improving treatment effects and sports performance. This technology is of irreplaceable importance in guiding rehabilitation treatment, improving exercise efficiency and reducing the incidence of injuries.

[0003] In the prior art, there are the following deficiencies for muscle force measurement. On the one hand, in terms of electrode materials, the accuracy of the electrodes prepared in the prior art is not enough. For example, Chinese patent CN115725026A proposes a hydrogel-based electromyographic electrode device, which uses the good biocompatibility and conductivity of hydrogel materials to obtain muscle electrical signals. Although it can capture the electrical signals generated by muscle contraction, it still has limitations when dealing with rapid and small strain changes in muscles. These electromyographic electrodes are often difficult to capture subtle mechanical signals in real time, resulting in limited accuracy and real-time performance of the data; for example, U.S. Patent US20210219895A1 discloses a wearable muscle activity sensor and electrode made of conductive polymer materials with certain flexibility and sensitivity. However, its preparation process involves complex multi-step chemical synthesis and high-temperature treatment, which is not only time-consuming and costly, but also difficult to meet the needs of rapid preparation and large-scale production, limiting its promotion in practical applications. On the other hand, the prior art has not yet disclosed a specific scheme for directly testing muscle force through electrode films, and all require indirect testing with the help of complex instruments and equipment, so the accuracy and convenience do not meet the current medical requirements.

[0004] Therefore, it is necessary to design a fast-polymerizing hydrogel film sensor for muscle force prediction to achieve more direct and higher-precision real-time monitoring and a simpler and low-cost manufacturing process. Summary of the invention

[0005] In order to at least solve the technical problems described in the above background technology section, the present invention proposes a method for preparing a hydrogel film sensor and a sensor for muscle force prediction. Using the scheme of the present invention, the accuracy and efficiency of muscle force testing are improved through the mapping relationship from resistance change to epidermal change to force testing. In view of this, the present invention provides solutions in the following aspects.

[0006] The first aspect of the present invention provides a method for manufacturing a hydrogel film sensor for muscle force prediction, wherein the hydrogel film sensor is used to predict muscle force, comprising: selecting a material ratio of a hydrogel precursor according to a sensitivity parameter and a mechanical stress parameter of the hydrogel film sensor; using the hydrogel precursor to prepare a hydrogel film, and symmetrically arranging electrodes on the left and right sides of the length direction of the hydrogel film to form a hydrogel film sensing structure; obtaining a change in the resistance value of the hydrogel film sensing structure, and forming a one-to-one correspondence with the strain value of the sensor for calibration; performing a strength test on a target muscle group, measuring the resistance value of the hydrogel film sensing structure tightly attached to the skin surface, and correlating the strength test result with the resistance change of the hydrogel film sensing structure to form a muscle force prediction model. :

[0007] ;

[0008] in, represents the muscle force prediction model, Indicates the calibration result. represents the resistance change of the hydrogel film sensing structure, Represents the initial resistance value of the hydrogel film sensing structure; and uses the muscle force prediction model to measure the muscle force.

[0009] In one embodiment, the hydrogel precursor material includes: glycerol, phytic acid, acrylamide, chitosan material, MXene single-layer nanosheets, and ammonium persulfate, and the mass percentage of phytic acid, ammonium persulfate, and MXene single-layer nanosheets is 12.5:1:1.

[0010] In one embodiment, the material ratio of the hydrogel precursor is specifically as follows: the concentration of each 10 ml solution contains 4.5 ml of glycerol solution, 5.5 ml of deionized water solution, 250 mg of phytic acid, 1250 mg of acrylamide, 150 mg of chitosan material, 20 mg of MXene monolayer nanosheets, and 20 mg of ammonium persulfate.

[0011] In one embodiment, the use of the hydrogel precursor to prepare a hydrogel film includes: adding a MXene single-layer nanosheet material to a mixture of polyacrylamide, chitosan, phytic acid and ammonium persulfate, and stirring the mixture to obtain a hydrogel precursor; using a polyvinyl chloride substrate to wrap the hydrogel precursor solution to form a sandwich structure; after the hydrogel precursor solution is cured, cutting the sandwich structure; soaking the cut sandwich structure in a glycerol solution for 30 minutes, and peeling off the polyvinyl chloride substrate to form the hydrogel film.

[0012] In one embodiment, the electrodes are symmetrically arranged on the left and right sides in the length direction of the hydrogel film to form a hydrogel film sensing structure, including: adhering electrode wires to the left and right sides in the length direction of the hydrogel film electrodes; and providing electrode packaging layers above the electrodes on the left and right sides respectively to form a symmetrical hydrogel film sensing structure, wherein the electrode packaging layers are used to protect the electrodes and wires.

[0013] In one embodiment, the method of obtaining the change in the resistance value of the hydrogel film sensing structure and forming a one-to-one correspondence with the strain value of the sensor includes: fixing the hydrogel film sensing structure and recording its initial resistance value when it is not under force; applying different forces to the hydrogel film sensing structure and recording the applied force value and resistance value; based on the initial resistance value, resistance value and force value, obtaining the force value corresponding to the unit resistance change value of the hydrogel film sensing structure.

[0014] The second aspect of the present invention provides a hydrogel film sensor for muscle force prediction, which is manufactured by any of the above-mentioned methods for manufacturing a fast polymerization hydrogel film sensor. It includes an electrode left packaging layer, an electrode left wire, a hydrogel film electrode, an electrode right wire, and an electrode right packaging layer connected in sequence from left to right, wherein the hydrogel film electrode is in the shape of a rectangle, the electrode left wire is attached to the left side of the hydrogel film electrode, and the electrode right wire is attached to the right side of the hydrogel film electrode; the electrode left packaging layer covers the electrode left wire and contacts the hydrogel film electrode, and the electrode right packaging layer covers the electrode right wire, and the connection position is symmetrical with the connection position of the electrode left packaging layer.

[0015] In one embodiment, the material of the electrode left packaging layer and the electrode right packaging layer are both polyurethane materials with adhesiveness on one side, which are used to fix the electrode left wire and the electrode right wire.

[0016] In one embodiment, the left electrode wire and the right electrode wire are both made of copper, and are used to extract the change of the resistance signal during the strain process of the hydrogel film electrode in real time.

[0017] Using the solution provided by the present invention, on the one hand, the hydrogel precursor materials are selected to include glycerol, phytic acid, acrylamide, chitosan material, MXene monolayer nanosheets, and ammonium persulfate, and the mass percentage of phytic acid, ammonium persulfate, and MXene monolayer nanosheets is 12.5:1:1; further provided and the material ratio is specifically: the concentration is 4.5 ml glycerol solution, 5.5 ml deionized water solution, 250 mg phytic acid, 1250 mg acrylamide, 150 mg chitosan material, 20 mg MXene monolayer nanosheets, and 20 mg ammonium persulfate per 10 ml solution. In the present invention, the above formula significantly shortens the formation time of the hydrogel film, improves the preparation efficiency, and the above formula ensures the high strength and high toughness mechanical properties of the hydrogel film, ensures the linearity of the resistivity change, and also provides a good basis for measuring muscle.

[0018] On the other hand, the present invention constructs a correlation prediction model between resistance change, skin deformation and muscle force. The present invention takes into account the technical problem that the presence of tiny wrinkles on the skin surface dilutes the size of the resistance change and leads to inaccurate muscle force testing through the hydrogel film. The accuracy of the muscle force test is improved through the muscle force prediction algorithm. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0020] Figure 1 It is a method for preparing a hydrogel thin film sensor according to an embodiment of the present invention;

[0021] Figure 2 1 is a diagram showing the preparation of a precursor liquid according to an embodiment of the present invention;

[0022] FIG3 (a) is a diagram showing the effect of chitosan concentration on mechanical properties according to an embodiment of the present invention;

[0023] FIG3( b ) is a diagram showing the effect of glycerol concentration on mechanical properties according to an embodiment of the present invention;

[0024] FIG3 (c) shows the effect of different MXene concentrations on mechanical properties according to an embodiment of the present invention;

[0025] Figure 4 The present invention shows the process of preparing a hydrogel film sensing structure according to an embodiment of the present invention;

[0026] Figure 51. It shows the principle of the hydrogel film sensor according to an embodiment of the present invention;

[0027] FIG6 (a) shows the resistance change within a 50% strain range of the original length of the sensor according to an embodiment of the present invention;

[0028] FIG6( b ) shows the response change of the sensor under the condition of 5% strain of the original length according to an embodiment of the present invention;

[0029] FIG6 (c) shows the recovery change of the original length of the sensor under 5% strain condition according to an embodiment of the present invention;

[0030] Figure 7 The muscle prediction model according to an embodiment of the present invention is shown;

[0031] Figure 8 A hydrogel thin film sensor according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0033] It should be understood that the terms "first", "second", "third" and "fourth" etc. in the claims, specifications and drawings of the present invention are used to distinguish different objects rather than to describe a specific order. The terms "include" and "comprise" used in the specification and claims of the present invention indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their collections.

[0034] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the claims, the singular forms of "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" used in the specification of the present invention and the claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0035] As used in this specification and claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0036] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0037] A first aspect of the present invention provides a skin sampling system for pathogen microscopic examination. Figure 1 is a schematic diagram showing a method for preparing a hydrogel thin film sensor for muscle force prediction according to an embodiment of the present invention. The method for preparing a hydrogel thin film sensor of the present invention comprises:

[0038] Step S100: selecting a material ratio of a hydrogel precursor according to a sensitivity parameter and a mechanical stress parameter of the hydrogel film sensor;

[0039] Step S200: using the hydrogel precursor to prepare a hydrogel film, and symmetrically arranging electrodes on the left and right sides of the length direction of the hydrogel film to form a hydrogel film sensing structure;

[0040] Step S300: obtaining a change in the resistance value of the hydrogel film sensing structure and forming a one-to-one correspondence with the strain value of the sensor for calibration;

[0041] Step S400: Perform a strength test on the target muscle group, measure the resistance value of the hydrogel film sensing structure closely attached to the skin surface, and associate the strength test result with the resistance change of the hydrogel film sensing structure to form a muscle force prediction model :

[0042] ;

[0043] in, represents the muscle force prediction model, Indicates the calibration result. represents the resistance change of the hydrogel film sensing structure, represents the initial resistance value of the hydrogel film sensing structure;

[0044] Step S500: Measuring muscle force using the muscle force prediction model.

[0045] In the present invention, the hydrogel film electrode is closely attached to the skin surface of the target part to ensure good contact between the electrode and the skin, so that the hydrogel film sensor can change shape with the movement of the skin. This configuration preferably ensures that the sensor can accurately capture the dynamic changes of the skin and the underlying muscle tissue during muscle movement.

[0046] Preferably, a high-precision multimeter is used to read the change in resistance of the hydrogel film electrode during muscle movement through the left electrode wire and the right electrode wire. This step preferably provides a resistance signal reflecting the state of muscle activity, laying a solid foundation for subsequent data analysis.

[0047] Preferably, the skin surface deformation value and muscle force value are tested, and these data are associated and calibrated with the resistance change of the hydrogel film electrode. Through this optimization process, an accurate correlation model between resistance change and muscle force is constructed, thereby optimizing the calibration accuracy of the sensor and ensuring that it can accurately reflect the actual changes in muscle force.

[0048] Preferably, a one-to-one correspondence between the resistance change of the hydrogel film electrode and the muscle force of the tested part is achieved. This process preferably ensures real-time and accurate prediction of muscle force, providing reliable technical support for muscle force testing and evaluation.

[0049] In a preferred embodiment of the present invention, the above step S100: selects the material ratio of the hydrogel precursor according to the sensitivity parameter and mechanical stress parameter of the hydrogel film sensor. The indicators that need to be considered in the hydrogel film sensor include: adhesion, strength, stretchability, linearity of resistance change, response time and recovery time, etc. Changing the ratio of any material will change the final performance result.

[0050] The rapid polymerization process used in this embodiment is as follows Figure 2 As shown, the efficient preparation process of hydrogel film precursor solution is described in detail:

[0051] In this process, the precursor solution of the hydrogel film electrode contains a small amount of phytic acid and ammonium persulfate. In the polymerization reaction, the MXene material undergoes a redox reaction with the ammonium persulfate to generate a large number of hydroxyl radicals. These free radicals significantly promote the polymerization of acrylamide monomers, thereby forming polyacrylamide with a three-dimensional network structure.

[0052] During this process, the oxidized MXene material undergoes a reduction reaction with phytic acid to generate materials for redox cycles again, further promoting the generation of free radicals. This reaction chain significantly accelerates the formation of the three-dimensional polyacrylamide network, thereby significantly shortening the preparation time of the hydrogel film electrode, allowing it to be completed within 1 minute.

[0053] This rapid polymerization method greatly improves production efficiency and significantly reduces preparation time, meeting the needs of rapid preparation of high-performance flexible sensors. This innovative technology not only improves the repeatability and consistency of production, but also ensures the high sensitivity and excellent performance of the sensor, providing key support for the development of flexible electronic devices.

[0054] Furthermore, in order to ensure the rapid polymerization reaction of the hydrogel film electrode and achieve the purpose of efficient production, the amount of phytic acid added in every 10 ml solution is set to 250 mg and the amount of ammonium persulfate added is set to 20 mg. The internal principle is that the phytic acid, MXene and ammonium persulfate work together to promote the efficient polymerization of acrylamide monomers, thereby significantly shortening the formation time of the hydrogel film and improving the preparation efficiency. MXene materials are added later.

[0055] In the above scheme of the present invention, in order to ensure the excellent mechanical properties of the hydrogel film electrode 3, including high strength and high toughness, the amount of acrylamide added in every 10 ml of the precursor solution is set to 2500 mg to form a highly cross-linked polyacrylamide network structure, thereby ensuring that it does not suffer mechanical damage or performance degradation during multiple cycles of strain.

[0056] In the above scheme of the present invention, in order to enhance the bioadhesion properties of the hydrogel film electrode 3, the optional addition amount of chitosan is set to 100, 200, 300, 400, and 500 mg. Chitosan has excellent biocompatibility and adhesion, ensuring that the hydrogel film exhibits excellent adhesion properties when attached to the skin surface, thereby improving the stability and reliability of the sensor.

[0057] In the above scheme of the present invention, in order to improve the moisture retention and flexibility of the hydrogel film electrode, the optional addition amount of glycerol is set to 1, 2, 3, 4, and 5 ml. Glycerol can effectively retain the moisture in the hydrogel, prevent the hydrogel from drying and hardening, thereby extending the service life of the sensor and maintaining its flexibility and functional integrity in long-term applications.

[0058] In the above scheme of the present invention, in order to improve the conductivity of the hydrogel film electrode 3, the optional addition amount of MXene in every 10 ml of the precursor solution is set to 10, 20, 30, and 40 mg. Due to its unique two-dimensional layered structure and excellent conductivity, MXene materials can significantly improve the conductivity of the hydrogel film, making it exhibit high sensitivity and low resistance characteristics in electrical signal transmission, thereby optimizing the electrical performance of the sensor.

[0059] In the above preferred materials, the effect of concentration change on the mechanical properties of the flexible substrate is shown in Figure 3 (a)-3 (c), wherein the horizontal and vertical axes of the attached figures represent tension in percentage (%); the vertical axis represents pressure in kilopascals (kPa). Figure 3 (a) represents the effect of different concentrations of chitosan on mechanical properties, Figure 3 (b) represents the effect of different concentrations of glycerol on mechanical properties, and Figure 3 (c) represents the effect of different concentrations of MXene on mechanical properties. Therefore, the above hydrogel precursor material is configured to include: glycerol, phytic acid, acrylamide, chitosan material, MXene monolayer nanosheets, and ammonium persulfate, and the mass percentage of phytic acid, ammonium persulfate, and MXene monolayer nanosheets is 12.5:1:1. The final preferred concentration is 4.5 ml of glycerol solution, 5.5 ml of deionized water solution, 250 mg of phytic acid, 1250 mg of acrylamide, 150 mg of chitosan material, 20 mg of MXene monolayer nanosheets, and 20 mg of ammonium persulfate per 10 ml of solution, so as to complete the polymerization reaction in a short time.

[0060] In a preferred embodiment of the present invention, the above step S200: using the hydrogel precursor to prepare a hydrogel film, and symmetrically arranging electrodes on the left and right sides of the length direction of the hydrogel film to form a hydrogel film sensing structure. The specific process can be seen in Figure 4 .

[0061] like Figure 4 As shown, after the preparation of the precursor mixture is completed, the resulting precursor solution is poured into a 5 ml glass bottle and fully stirred using a high-efficiency oscillating mixer to ensure that all components are evenly mixed to avoid uneven polymerization problems, thereby ensuring the overall performance consistency of the hydrogel thin film electrode.

[0062] In the above scheme of the present invention, the uniformly mixed precursor solution is carefully poured onto the polyvinyl chloride substrate coated with fluorosilane. The polyvinyl chloride substrate treated with fluorosilane provides excellent anti-adhesion properties, which is helpful for the complete peeling of the subsequent hydrogel film.

[0063] In the above scheme of the present invention, a resin interlayer of a predetermined thickness is placed to control the final thickness and shape of the hydrogel film. By using a polyvinyl chloride substrate of the same material to wrap the precursor solution to form a sandwich structure, the hydrogel is effectively prevented from deforming during the curing process, ensuring that the prepared hydrogel film has a uniform thickness and a smooth surface. The thickness can be selected to be 100, 300, or 500 μm.

[0064] In the above scheme of the present invention, the sandwich structure is appropriately pressed by using a steel metal plate interlayer that is symmetrical up and down, so as to achieve high-quality molding of the hydrogel film and avoid the problem of inconsistent mechanical properties caused by uneven thickness.

[0065] In the above scheme of the present invention, after the hydrogel film is cured, a 50×15 mm custom steel die cutter is used to precisely cut the hydrogel film to obtain a hydrogel film structure of a desired size.

[0066] In the above scheme of the present invention, the cut hydrogel film structure is immersed in a glycerol solution for 30 minutes, which can help reduce the adhesion between the hydrogel film and the polyvinyl chloride substrate, and further enhance the flexibility and moisture retention of the hydrogel, ensuring the integrity and structural stability during the peeling process. Finally, a complete and stable hydrogel film structure is obtained after peeling.

[0067] After the hydrogel film structure is prepared, the hydrogel film sensor preparation process needs to be carried out. In the wire arrangement and adhesion operation, the left wire of the electrode is firmly adhered to the left side of the hydrogel film electrode, and the right wire of the electrode is adhered to the right side of the hydrogel film electrode to ensure a firm connection between the wire and the hydrogel electrode, and maintain the continuity and stability of the conductive path, thereby ensuring the accuracy of signal transmission and the overall reliability of the sensor; in the covering and fixing operation of the packaging layer, the left packaging layer of the electrode is covered on the left wire of the electrode, and the right packaging layer of the electrode is covered on the right wire of the electrode to form a symmetrical packaging structure. The packaging structure is designed to provide excellent mechanical protection to prevent damage to the electrodes and wires by the external environment, while ensuring the structural stability and durability of the entire sensor system.

[0068] In the above scheme of the present invention, the hydrogel film electrode is precisely attached to the skin surface of the target part to ensure close contact between the electrode and the skin, so that the electrode can undergo corresponding morphological changes with the dynamic movement of the skin. This design preferably realizes an effective interface between the electrode and the skin surface, ensuring that the sensor can efficiently and accurately capture the tiny deformation of the skin and the muscle tissue underneath during muscle movement, further improving the sensitivity and accuracy of detection.

[0069] In a preferred embodiment of the present invention, the above step S300: obtaining the change in the resistance value of the hydrogel film sensing structure and forming a one-to-one correspondence with the strain value of the sensor for calibration, specifically, is as follows:

[0070] like Figure 5 As shown, the hydrogel film sensor is connected to the circuit for testing and calibration. A high-precision LCR multimeter is used in the circuit to monitor the resistance changes of the hydrogel film electrode during muscle movement in real time by connecting the left electrode wire and the right electrode wire. This step preferably provides a high-precision resistance signal directly related to the muscle activity state, laying a solid foundation for subsequent data analysis. This method of obtaining resistance signals not only improves the reliability of the data, but also ensures the consistency and accuracy of the measurement results.

[0071] In the above scheme of the present invention, the resistance change formula of the piezoresistive strain flexible sensor is: That is, the change in the resistance value of the hydrogel film sensor is collected through a precision LCR meter, and a one-to-one correspondence is formed with the strain value of the sensor to complete the calibration process. The calibration result is shown in Figure 6 (a). The calibration process can intuitively reflect the deformation value of the surface to which the hydrogel film sensor is attached. Figure 6 (a) shows the resistance change of this embodiment within the strain range of 50% of the original length of the sensor. The results show that the linearity of the resistance change exceeds 99.8%. This excellent linear characteristic highlights the superiority of the fast polymerization hydrogel film sensor of the present invention in design and functional realization, especially within the strain range of skin attachment, the sensor exhibits extremely high linear response capabilities. Such precise linear performance ensures that the sensor can accurately capture the tiny deformation of the skin and the muscle tissue underneath it during the detection process, thereby achieving highly accurate prediction of muscle force and meeting the strict requirements of muscle force assessment.

[0072] Figures 6 (b) and 6 (c) further show the change of resistance over time under the condition of 5% strain of the original length of the sensor in this embodiment, and the response time and recovery time are 207 milliseconds and 200 milliseconds respectively. This excellent fast real-time dynamic response characteristic shows that the sensor can quickly capture the subtle changes in resistance at the moment of rapid muscle contraction and relaxation, thereby realizing instant and accurate monitoring of muscle force. This excellent dynamic response capability not only enhances the adaptability and reliability of the sensor in complex motion states, but also ensures the accuracy and consistency of muscle force prediction, significantly improving the application potential of the sensor in high-precision muscle force assessment.

[0073] It can be seen from the test results that the fast polymerization hydrogel film sensor provided by the present invention exhibits extremely excellent performance in terms of the linearity of strain response and the dynamic response speed, fully meeting the technical requirements of high-precision and real-time muscle force prediction.

[0074] In a preferred embodiment of the present invention, the above step S400: performing a strength test on the target muscle group, measuring the resistance value of the hydrogel film sensing structure closely attached to the skin surface, and correlating the strength test result with the resistance change of the hydrogel film sensing structure to form a muscle force prediction model, specifically:

[0075] After calibration, a hand dynamometer was used to test the strength of the forearm muscles. The resistance value of the hydrogel film sensor tightly attached to the skin surface was measured at the same time. The hand dynamometer force value was correlated with the resistance change of the hydrogel film sensor.

[0076] Through the above steps, a correlation prediction model between resistance change, skin deformation and muscle force is constructed, and the model is a linear relationship, such as Figure 7 As shown, the specific formula is , The reason why the muscle force prediction model finally obtained deviates from the calibration model formula is that the tiny wrinkles on the skin surface dilute the resistance change, thus presenting a result different from the sensor calibration formula. The construction of this model significantly optimizes the calibration accuracy of the sensor, ensuring that it can truly and reliably reflect the actual changes in muscle force, thereby improving the performance of the sensor in practical applications.

[0077] In the above scheme of the present invention, the fast-polymerizing hydrogel film sensor provided for muscle force prediction shows excellent linearity of resistance change in its design and functional realization, especially in the skin adhesion strain range, showing extremely high linear characteristics. This linearity ensures that the sensor can accurately reflect the subtle deformation of the skin and the muscle tissue underneath it during the detection process, thereby achieving high-precision prediction of muscle force. A one-to-one correspondence is established between the resistance change of the hydrogel film electrode and the muscle force of the measured part. Since the change in the resistance value of the hydrogel film sensor has good timeliness, this step preferably ensures that the sensor can make real-time and accurate predictions of muscle force, providing reliable technical support for muscle force testing and evaluation. Through this implementation path, the sensor can show excellent performance in a variety of application scenarios and meet the technical requirements of high-precision biomechanical sensing.

[0078] According to the above method, the second aspect of the present invention provides a hydrogel film sensor for muscle force prediction, the specific structure of which is as follows: Figure 8 shown. Figure 8 In the figure, 1 represents the left packaging layer of the electrode, 2 represents the left wire of the electrode, 3 represents the hydrogel film electrode, 4 represents the right wire of the electrode, and 5 represents the right packaging layer of the electrode.

[0079] See also Figure 5 The hydrogel sensor structure includes an electrode left packaging layer, an electrode left wire, a hydrogel film electrode, an electrode right wire, and an electrode right packaging layer connected from left to right in sequence. The hydrogel film electrode is in the shape of a rectangle. The electrode left wire is attached to the left side of the hydrogel film electrode, and the electrode right wire is attached to the right side of the hydrogel film electrode. The electrode left packaging layer covers the electrode left wire and contacts the hydrogel film electrode. The electrode right packaging layer covers the electrode right wire, and the connection position is symmetrical with the connection position of the electrode left packaging layer.

[0080] In one embodiment, the material of the electrode left packaging layer and the electrode right packaging layer are both polyurethane materials with adhesiveness on one side, which are used to fix the electrode left wire and the electrode right wire.

[0081] In one embodiment, the left electrode wire and the right electrode wire are both made of copper, and are used to extract the change of the resistance signal during the strain process of the hydrogel film electrode in real time.

[0082] Although this specification has shown and described a plurality of embodiments of the present invention, it is obvious to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art will appreciate many changes, modifications and alternatives without departing from the thought and spirit of the present invention. It should be understood that in the process of practicing the present invention, various alternatives to the embodiments of the present invention described herein may be adopted. The attached claims are intended to define the scope of protection of the present invention, and therefore cover the modular compositions, equivalents or alternatives within the scope of these claims.

Claims

1. A method for manufacturing a hydrogel thin film sensor for predicting muscle force, wherein the hydrogel thin film sensor is used to predict muscle force, characterized in that include: Selecting a material ratio of a hydrogel precursor according to a sensitivity parameter and a mechanical stress parameter of the hydrogel thin film sensor; Using the hydrogel precursor, a hydrogel film is prepared, and electrode wires are symmetrically arranged on the left and right sides of the length direction of the hydrogel film to form a hydrogel film sensing structure; Obtaining the change in the resistance value of the hydrogel film sensing structure and forming a one-to-one correspondence with the strain value of the sensor for calibration; Perform strength tests on the target muscle groups, measure the resistance value of the hydrogel film sensing structure that is closely attached to the skin surface, and correlate the strength test results with the resistance change of the hydrogel film sensing structure to form a muscle force prediction model : ； in, represents the muscle force prediction model, Indicates the calibration result. represents the resistance change of the hydrogel film sensing structure, Indicates the initial resistance value of the hydrogel film sensing structure; the muscle force prediction model is used to eliminate the inaccuracy of muscle force testing through the hydrogel film caused by the change in resistance due to the presence of tiny wrinkles on the skin surface; The step of obtaining the change in the resistance value of the hydrogel film sensing structure and forming a one-to-one correspondence with the strain value of the sensor comprises: Fixing the hydrogel film sensing structure and recording its initial resistance value in a state without stress; Apply different forces to the hydrogel film sensing structure and record the applied force value and resistance value; Based on the initial resistance value, the resistance value, and the force value, obtaining a force value corresponding to a unit resistance change value of the hydrogel film sensing structure; The muscle force prediction model is used to measure the muscle force.

2. The method for manufacturing a hydrogel thin film sensor for muscle force prediction according to claim 1, characterized in that: The hydrogel precursor material includes: glycerol, phytic acid, acrylamide, chitosan material, MXene single-layer nanosheets, and ammonium persulfate, and the mass percentage of phytic acid, ammonium persulfate, and MXene single-layer nanosheets is 12.5:1:

1.

3. The method for manufacturing a hydrogel film sensor for muscle force prediction according to claim 2, characterized in that: The material ratio of the hydrogel precursor is specifically as follows: The concentration is 4.5 ml glycerol solution, 5.5 ml deionized water solution, 250 mg phytic acid, 1250 mg acrylamide, 150 mg chitosan material, 20 mg MXene monolayer nanosheets, and 20 mg ammonium persulfate per 10 ml solution.

4. The method for manufacturing a hydrogel film sensor for muscle force prediction according to any one of claims 1 to 3, characterized in that: The method of using the hydrogel precursor to prepare a hydrogel film comprises: Adding MXene single-layer nanosheet material to a mixture of polyacrylamide, chitosan, phytic acid and ammonium persulfate, and stirring thoroughly to obtain a hydrogel precursor; Using a polyvinyl chloride base plate to wrap the hydrogel precursor to form a sandwich structure; after the hydrogel precursor is cured, cutting the sandwich structure; The cut sandwich structure was soaked in a glycerol solution for 30 minutes, and the polyvinyl chloride substrate was peeled off to form the hydrogel film.

5. The method for manufacturing a hydrogel film sensor for muscle force prediction according to claim 4, characterized in that: The electrode wires are symmetrically arranged on the left and right sides of the length direction of the hydrogel film to form a hydrogel film sensing structure, including: Adhere the electrode wires to the left and right sides of the hydrogel film in the length direction; Electrode packaging layers are respectively arranged above the electrode wires on the left and right sides to form a symmetrical hydrogel film sensing structure. The electrode packaging layers are used to protect the electrode wires and the hydrogel film.

6. A hydrogel thin film sensor for muscle force prediction, manufactured by the method for manufacturing a hydrogel thin film sensor for muscle force prediction according to any one of claims 1 to 5, characterized in that: It includes an electrode left packaging layer, an electrode left wire, a hydrogel film, an electrode right wire, and an electrode right packaging layer which are connected in sequence from left to right. The hydrogel film is in a rectangular shape, the left electrode lead is attached to the left side of the hydrogel film, and the right electrode lead is attached to the right side of the hydrogel film; The left packaging layer of the electrode covers the left wire of the electrode and contacts the hydrogel film. The right packaging layer of the electrode covers the right wire of the electrode, and the connection position is symmetrical to the connection position of the left packaging layer of the electrode.

7. The hydrogel film sensor for muscle force prediction according to claim 6, characterized in that: The material of the electrode left packaging layer and the electrode right packaging layer are both polyurethane materials with adhesiveness on one side, which are used to fix the electrode left wire and the electrode right wire.

8. The hydrogel film sensor for muscle force prediction according to claim 7, characterized in that: The left electrode wire and the right electrode wire are both made of copper and are used to extract the change of the resistance signal during the strain process of the hydrogel film in real time.

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