A flexible sensing device for rapid monitoring of the elastic modulus of human skin tissue

Abstract

The present invention relates to the field of wearable monitoring, and discloses a flexible sensing device for rapid monitoring of the elastic modulus of human skin tissue, including a reference sensor, a structural sensing layer, and an ultra-thin electrode; the reference sensor consists of a standard flexible pressure sensor, which includes three parts: a flexible substrate, interdigital electrode I, and a structured electrode layer; the structural sensing layer consists of microstructures, interdigital electrode II, and a flexible polymer film, the interdigital electrode II is connected to polystyrene microspheres, and the flexible polymer film is connected to the interdigital electrode II; the ultra-thin electrode is composed of a conductive metallization network. This flexible sensing device for rapid measurement of the elastic modulus of skin tissue realizes the portable measurement of the elastic modulus of human skin for the first time, can be detected without complex instruments, and has potential application value in skin aging diagnosis, skin inflammation monitoring, and the field of medical aesthetics.

Description

Technical Field

[0001] The present invention relates to the field of wearable monitoring devices, and specifically to a flexible sensing device for rapid monitoring of the elastic modulus of human skin tissue. Background Art

[0002] The human skin is a soft organ with a Young's modulus of about 0.1 - 2 MPa. Skin tissue lesions such as skin sclerosis, inflammation, and external force damage are all accompanied by changes in the skin tissue modulus. Therefore, rapid and accurate measurement of the skin tissue elastic modulus is of great significance.

[0003] Currently, the methods for measuring soft materials include static indentation method and dynamic conformal thin film sensing method, but it is difficult to achieve portable or wearable real-time monitoring. Currently, the test of skin tissue elastic modulus has not achieved flexible, wearable and portable monitoring. With the rapid development of flexible sensing devices in the field of health monitoring, it is of great significance to develop a portable and wearable device for monitoring the elastic modulus of human skin tissue.

[0004] Therefore, we propose a flexible sensing device for rapid measurement of skin tissue elastic modulus. Summary of the Invention

[0005] (I) Technical Problems to be Solved

[0006] In view of the deficiencies of the prior art, the present invention provides a flexible sensing device for rapid measurement of skin tissue elastic modulus, which solves the above problems.

[0007] (II) Technical Solutions

[0008] To achieve the above object, the present invention provides the following technical solution: A flexible sensing device for rapid monitoring of the elastic modulus of human skin tissue, comprising a reference sensor, a structural sensing layer, and an ultra-thin electrode;

[0009] The reference sensor consists of a standard flexible pressure sensor, which includes three parts: a flexible substrate, interdigital electrode I, and a structured electrode layer;

[0010] The structural sensing layer is composed of microstructures, interdigital electrode II, and a flexible polymer film. Interdigital electrode II is connected to polystyrene microspheres, and the flexible polymer film is connected to interdigital electrode II;

[0011] The ultra-thin electrode is composed of a conductive metallization network. The ultra-thin electrode is disposed below the structural sensing layer, and the structural sensing layer is disposed below the reference sensor.

[0012] Preferably, the flexible substrate is a polymer film such as polyethylene terephthalate, polyimide, polystyrene, etc., with a thickness of 100 microns to 1 mm.

[0013] Preferably, the material of the first interdigital electrode is chromium gold or copper nickel, and it is prepared by magnetron sputtering, thermal evaporation or electrodeposition methods.

[0014] Preferably, the structured electrode layer can be spherical, pyramid-shaped, columnar or an uneven structure with disordered distribution, etc.

[0015] Preferably, the microstructures in the structural sensing layer are spherical protrusions formed by embedding polystyrene microspheres on the surface of a flexible polymer film. The height of the protrusions is 10 to 200 micrometers, and the diameter of the polystyrene microspheres is 10 to 500 micrometers.

[0016] Preferably, the first interdigital electrode in the structural sensing layer is a chromium gold interdigital electrode prepared by magnetron sputtering.

[0017] Preferably, the conductive metallization network of the ultra-thin electrode is an electrospun polyvinyl alcohol non-woven fabric film with a gold coating on the surface. The thickness of the gold coating is 50 nanometers, and the non-woven fabric film has a thickness of 1 to 500 micrometers.

[0018] (III) Beneficial effects

[0019] Compared with the prior art, the present invention provides a flexible sensing device for rapid monitoring of the elastic modulus of human skin tissue, which has the following beneficial effects:

[0020] 1. This flexible sensing device for rapid monitoring of the elastic modulus of human skin tissue realizes the portable measurement of the elastic modulus of human skin for the first time by using a flexible sensing device. It can be detected without complex instrument equipment and has potential application value in skin aging diagnosis, skin inflammation monitoring and the field of medical aesthetics. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the present invention.

[0022] In the figure: 1. Flexible substrate; 2. First interdigital electrode; 3. Structured electrode layer; 4. Flexible polymer film; 5. Second interdigital electrode; 6. Polystyrene microspheres; 7. Ultra-thin electrode; 8. Skin tissue. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0024] Please refer to Figure 1, A flexible sensing device for rapid monitoring of the elastic modulus of human skin tissue, including a reference sensor, a structural sensing layer, and an ultra-thin electrode 7;

[0025] The reference sensor consists of a standard flexible pressure sensor, including a flexible substrate 1, interdigital electrode 1 2, and a structured electrode layer 3;

[0026] The structural sensing layer consists of microstructures, interdigital electrode 2 5, and a flexible polymer film 4. The interdigital electrode 2 5 is connected to polystyrene microspheres 6, and the flexible polymer film 4 is connected to the interdigital electrode 2 5;

[0027] The ultra-thin electrode 7 is composed of a conductive metallization network. The ultra-thin electrode 7 is disposed below the structural sensing layer, and the structural sensing layer is disposed below the reference sensor.

[0028] Furthermore, the flexible substrate 1 is a polymer film such as polyethylene terephthalate, polyimide, or polystyrene, with a thickness of one hundred micrometers to one millimeter.

[0029] Furthermore, the material of the interdigital electrode 1 2 is chromium gold or copper nickel, and it is prepared by magnetron sputtering, thermal evaporation, or electrodeposition methods.

[0030] Furthermore, the structured electrode layer 3 can be spherical, pyramid-shaped, columnar, or randomly distributed concave-convex structures, etc.

[0031] Furthermore, the microstructures in the structural sensing layer are spherical protrusions formed by embedding polystyrene microspheres 6 on the surface of the flexible polymer film 4. The height of the protrusions is ten to two hundred micrometers, and the diameter of the polystyrene microspheres 6 is ten to five hundred micrometers.

[0032] Furthermore, the interdigital electrode 1 2 in the structural sensing layer is a chromium gold interdigital electrode prepared by magnetron sputtering.

[0033] Furthermore, the conductive metallization network of the ultra-thin electrode 7 is an electrospun polyvinyl alcohol non-woven fabric film with a gold coating on the surface, where the gold coating thickness is fifty nanometers, and the non-woven fabric film has a thickness of one to five hundred micrometers.

[0034] The working principle of the flexible sensing device is as follows:

[0035] First, attach the ultra-thin electrode 7 to the skin surface, specifically as follows: moisten the skin surface with water vapor, attach the gold-coated polyvinyl alcohol non-woven fabric film to the skin surface. The polyvinyl alcohol dissolves in water and forms a gold film on the skin surface, which is the ultra-thin electrode 7.

[0036] When the structural sensing layer contacts the ultra-thin electrode 7, as the pressure increases, the contact area increases, resulting in a decrease in the contact resistance. The magnitude of the skin tissue modulus directly affects the embedding depth of the polystyrene spheres 6 in the structural sensing layer. Therefore, the contact resistance between the structural sensing layer and the ultra-thin electrode 7 can indirectly reflect the magnitude of the skin tissue modulus.

[0037] Due to different pressures, the contact resistance between the structural sensing layer and the ultra-thin electrode 7 is different. Therefore, a reference sensor is used for calibration to calculate the change in the contact resistance between the structural sensing layer and the ultra-thin electrode 7 under different pressures, and the magnitude of the skin tissue modulus can be calculated.

[0038] Example: As shown in the figure

[0039] Preparation of flexible interdigital electrodes: Select a polyethylene terephthalate film with a thickness of 50 microns as the flexible substrate 1. Then, by means of magnetron sputtering, 5-nanometer chromium metal and 50-nanometer gold are successively deposited on the masked flexible substrate 1. After removing the mask, a 10×10 flexible interdigital electrode 2 with a line width of 50 microns, a line length of 5 millimeters, and a line spacing of 50 microns is obtained.

[0040] Preparation of the flexible polymer film 4 with microstructures: First, spray a graphene ethanol solution with a concentration of 5 mg / mL on the surface of a polytetrafluoroethylene sheet to form a conductive graphene film. Then, prepare a polyvinylidene fluoride / N,N-dimethylformamide solution with a mass concentration of 15 wt%, add an equal amount of polystyrene microspheres 6 with an average diameter of 80 microns, stir evenly, and use the solution casting method to prepare the flexible polymer film 4 on the surface of the graphene film. Dry it at 70 degrees for 3 h to obtain a structured electrode layer 3 with a film thickness of 30 microns and slightly raised on one side, and polystyrene spheres 6 with higher protrusions on the other side.

[0041] Prepare interdigital electrodes on the surface of the polyvinylidene fluoride polymer film with polystyrene spheres 6; by means of magnetron sputtering, deposit 5-nanometer chromium metal and 50-nanometer gold successively on the surface of the masked film. After removing the mask, a 5×5 flexible interdigital electrode 5 with a line width of 1 millimeter, a line length of 6 millimeters, and a line spacing of 0.5 millimeter is obtained.

[0042] Preparation of the ultra-thin electrode 7: The ultra-thin electrode 7 is a kind of conductive metallized network. First, use the electrospinning method to prepare a polyvinyl alcohol non-woven fabric film with a thickness of 10 microns, and use the magnetron sputtering method to deposit 50-nanometer gold on its surface to obtain a conductive non-woven fabric. Wet the skin surface with water mist, stick the conductive non-woven fabric to the skin surface. After the polyvinyl alcohol is dissolved, a ultra-thin gold film electrode is formed on the skin surface, which is the ultra-thin electrode 7.

[0043] Assembly of the flexible sensing device: The above-mentioned flexible interdigital electrode II 5, the flexible polymer film 4 with microstructures, the interdigital electrode I 2, etc. are assembled layer by layer, and the periphery is encapsulated with epoxy resin glue to obtain the flexible sensing device.

[0044] Place the flexible sensing device on the skin surface to be detected, make contact with the ultra-thin electrode 7. Under different pressures, the polystyrene microspheres 6 are embedded into the skin, and the resistance or capacitance signals of the chromium-gold interdigital electrode II 5 are collected. Change the pressure applied to the flexible substrate 1 multiple times, collect the resistance or capacitance signals of the chromium-gold interdigital electrode 5, and calculate the elastic modulus of the skin tissue.

[0045] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A flexible sensing device for rapid monitoring of the elastic modulus of human skin tissue, characterized in that, It includes a reference sensor, a structural sensing layer, and an ultra-thin electrode (7); The reference sensor is composed of three parts: a flexible substrate (1), a first interdigital electrode (2), and a structured electrode layer (3); The structural sensing layer is composed of a microstructure, a second interdigital electrode (5), and a flexible polymer film (4). The microstructure is spherical protrusions formed by embedding polystyrene microspheres (6) on the surface of the flexible polymer film (4). The height of the protrusions is 10 to 200 microns, and the diameter of the polystyrene microspheres (6) is 10 to 500 microns. The second interdigital electrode (5) is connected to the polystyrene microspheres (6), and the flexible polymer film (4) is connected to the second interdigital electrode (5). The average diameter of the polystyrene microspheres (6) is 80 microns; The ultra-thin electrode (7) is composed of a conductive metallization network, which is an electrospun polyvinyl alcohol non-woven fabric film with gold plating on the surface. The gold plating thickness is 50 nanometers, and the non-woven fabric film has a thickness of 1 to 500 microns. The ultra-thin electrode (7) is arranged below the structural sensing layer, and the structural sensing layer is arranged below the reference sensor.

2. The flexible sensing device for rapid monitoring of the elastic modulus of human skin tissue according to claim 1, characterized in that: The flexible substrate (1) is any one of polyethylene terephthalate, polyimide, or polystyrene, with a thickness of 100 microns to 1 millimeter.

3. The flexible sensing device for rapid monitoring of the elastic modulus of human skin tissue according to claim 1, characterized in that: The first interdigital electrode (2) is made of chromium gold or copper nickel, and is prepared by magnetron sputtering, thermal evaporation, or electrodeposition methods.

4. The flexible sensing device for rapid monitoring of the elastic modulus of human skin tissue according to claim 1, characterized in that: The structured electrode layer (3) is a spherical, pyramid-shaped, columnar, or randomly distributed concave-convex structure.

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