Implementation method of electronic skin and physiological signal monitoring system

Abstract

The invention discloses an electronic skin implementation method and a physiological signal monitoring system. The electronic skin provided by the invention comprises a sensing platform and a plurality of sensing units arranged on the sensing platform, the sensing platform is of an island bridge structure and comprises a first material and a second material, the first material is a stretchable material, and the second material is a non-stretchable material; the sensing platform is prepared by carrying out silanization treatment on the second material and then adhering the second material with the first material; the sensing unit is arranged on the second material; the sensing unit comprises a sensitive film and an electrode, and the sensing unit is used for measuring temperature, humidity or oxygen. According to the embodiment of the invention, the stretchable sensor is realized through the sensing platform of the island bridge structure; signal measurement is carried out through the sensitive film, multi-target measurement can be achieved, the tensile property of the electronic skin is improved, and meanwhile convenient monitoring is achieved. The method can be widely applied to the technical field of signal measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of signal measurement, and in particular to an electronic skin realization method and a physiological signal monitoring system. Background Art

[0002] In the process of chronic disease management, continuous monitoring and data analysis of the condition are crucial. Traditional medical monitoring methods are often limited by time and place, making it difficult to achieve real-time monitoring of the condition. The emergence of portable wearable sensor devices has changed this situation, making it possible to continuously collect patients' physiological information. However, wearable sensor devices are mostly rigid structures and are easily interfered by mechanical damage and fail. Therefore, it is necessary to give the sensor flexibility and stretchability so that the device can fit better to the surface of human skin or clothing, and improve its working stability and reliability when the human body is in motion. In addition, compared with single physiological signal monitoring, combining the monitoring results of multiple physiological signals will provide doctors with more effective information for diagnosing and treating diseases. Among them, body temperature, body surface humidity, exhaled breath humidity and TcPO 2 It is one of the important physiological signals for patients with chronic diseases such as diabetic foot, chronic lower limb severe ischemia and obstructive sleep apnea hypopnea syndrome. Therefore, the development of flexible and stretchable multifunctional physiological signal sensing equipment can monitor and record the changes of relevant signs of patients with chronic diseases in real time, which will effectively assist doctors in disease diagnosis and treatment.

[0003] The skin contains many receptors that encode environmental stimuli and can sense pressure, temperature, and humidity, thereby establishing a connection between an individual and his surroundings. In response to this, materials that can contact the skin and measure signals are being used in various types of sensors. Among them, the stretchability and multisensitivity of hydrogels bring convenience, but also bring problems such as interference with response signals and crosstalk between multiple stimuli. Many methods have been developed to mitigate the effects of strain, including serpentine, spiral, and wrinkled structures, as well as composite materials. However, existing structural and material designs are either too complex or insufficient in effectively isolating strain. At the same time, the coupling interference of multiple signals makes it difficult to achieve high sensitivity and high selectivity detection of different stimuli by multifunctional sensors. Researchers have explored different methods to solve and minimize the crosstalk problem associated with multiple stimuli. For example, encapsulation can help isolate the effects of ambient humidity and gas on sensing, but it may not be suitable for humidity and gas sensing itself. Creating unique sensing mechanisms for specific stimuli can help distinguish between various stimulus sources. However, due to the aqueous nature of hydrogels, it is difficult to exclude the effects of ambient humidity on sensing. Therefore, effectively solving the crosstalk problem poses a major obstacle to multifunctional sensing in hydrogels. Summary of the invention

[0004] The purpose of the present invention is to solve one of the technical problems existing in the prior art to at least a certain extent.

[0005] To this end, the purpose of the present invention is to provide an efficient electronic skin implementation method and a physiological signal monitoring system.

[0006] In order to achieve the above technical objectives, the technical solutions adopted by the embodiments of the present invention include the following aspects:

[0007] On the one hand, an embodiment of the present invention provides an electronic skin, which includes: a sensing platform, and a plurality of sensing units arranged on the sensing platform; the sensing platform is an island bridge structure, the sensing platform includes a first material and a second material, the first material is a stretchable material, and the second material is a non-stretchable material; the sensing platform is made by bonding the second material with the first material after silanization treatment; the sensing unit is arranged on the second material; the sensing unit includes a sensitive film and an electrode, and the sensing unit is used to measure temperature, humidity or oxygen. The embodiment of the present application realizes a stretchable sensor through a sensing platform with an island bridge structure; by measuring signals through a sensitive film, it is possible to realize multi-target measurement, improve the stretchability of the electronic skin, and at the same time, realize convenient monitoring.

[0008] In addition, the electronic skin according to the above embodiment of the present invention may also have the following additional technical features:

[0009] Furthermore, in the electronic skin of the embodiment of the present invention, the sensing platform is a three-layer structure, the first layer is used to measure the humidity and oxygen in the air, the second layer is used to measure the body temperature of the object, and the third layer is used to measure the humidity and TcPO of the skin surface when contacting the skin surface of the object. 2 concentration.

[0010] Further, in one embodiment of the present invention, the first material includes PDMS, the second material includes PET, and the sensitive film includes a PAM / Carr-LiBr hydrogel film.

[0011] On the other hand, an embodiment of the present invention provides a method for realizing electronic skin, which is used to prepare the above-mentioned electronic skin, and the method includes:

[0012] Take a number of metal sheets, and prepare a first material film on the metal sheets as a substrate;

[0013] Performing silanization treatment on the cut second material film to obtain a plurality of islands;

[0014] The islands are bonded to the substrate, electrodes are fixed on each island and covered with a sensitive film to obtain the electronic skin.

[0015] Furthermore, in one embodiment of the present invention, the cut second material film is subjected to silanization treatment to obtain a plurality of islands, including:

[0016] Cleaning the surface of the second material film with deionized water and isopropyl alcohol, and performing air plasma treatment for a first time period;

[0017] Immersing the treated second material film in an APTES solution and heating it at a first temperature for a second period of time to perform a silanization treatment;

[0018] The second material film was taken out, rinsed with deionized water and blown dry with a nitrogen gun to obtain several islands.

[0019] Further, in one embodiment of the present invention, bonding the island to the substrate comprises:

[0020] performing air plasma treatment on the surface of the first material film and the second material film after silanization for a third time period;

[0021] The first material film and the second material film that have been bonded are bonded with Dragon skin prepolymer and cured at a second temperature for a fourth period of time to obtain a sensing platform.

[0022] Further, in one embodiment of the present invention, the sensitive film comprises a PAM / Carr-LiBr hydrogel film, and the PAM / Carr-LiBr hydrogel film is prepared by the following steps:

[0023] Weighing acrylamide, carrageenan, N-methylenebisacrylamide, potassium chloride, a photoinitiator, and deionized water in a preset ratio, heating in an oil bath at a third temperature for a fifth time to obtain a precursor solution;

[0024] preparing a PDMS prepolymer, spin coating the PDMS prepolymer on an aluminum sheet at a preset speed, and after curing, plasma treating the PDMS surface for a sixth period of time;

[0025] Dropping the precursor solution on the plasma-treated PDMS, and spin coating the PDMS to obtain a thin precursor layer;

[0026] After the precursor thin layer was refrigerated, a LiBr solution was drop-coated on the surface of the precursor thin layer, and the precursor thin layer was placed under an ultraviolet lamp for photoinitiation for 2 hours to obtain a PAM / Carr-LiBr hydrogel film.

[0027] Furthermore, in one embodiment of the present invention, the sensitive film comprises an ion gel film, and the ion gel film is prepared by the following steps:

[0028] An ion gel precursor solution was prepared by acetone;

[0029] The ion gel precursor solution is poured onto an aluminum substrate and kept for a seventh period of time to obtain an ion gel after the solvent is completely evaporated.

[0030] Furthermore, in one embodiment of the present invention, the electronic skin is measured by the following steps:

[0031] Measuring a first temperature, a first humidity, and a first oxygen through the electronic skin;

[0032] Determine that the first temperature is a temperature measurement result, and decouple the first humidity according to the temperature measurement result to obtain a humidity measurement result;

[0033] The first oxygen is decoupled according to the temperature measurement result and the humidity measurement result to obtain an oxygen measurement result.

[0034] On the other hand, an embodiment of the present invention provides a physiological signal monitoring system, including: the electronic skin as described above, a control module, and a wireless module;

[0035] The control module is used to send a control signal to enable the electronic skin to measure temperature, humidity or oxygen, obtain a measurement signal, process the measurement signal, and send the processed measurement signal to the target terminal through the wireless module.

[0036] The electronic skin provided by the embodiment of the present invention includes: a sensing platform, and a plurality of sensing units arranged on the sensing platform; the sensing platform is an island bridge structure, the sensing platform includes a first material and a second material, the first material is a stretchable material, and the second material is a non-stretchable material; the sensing platform is made by bonding the second material with the first material after silanization treatment; the sensing unit is arranged on the second material; the sensing unit includes a sensitive film and an electrode, and the sensing unit is used to measure temperature, humidity or oxygen. The embodiment of the present application realizes a stretchable sensor through a sensing platform with an island bridge structure; by measuring signals through a sensitive film, it is possible to realize multi-target measurement, improve the stretchability of the electronic skin, and at the same time, realize convenient monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the embodiments of the present invention or the drawings of related technical solutions in the prior art are introduced below. It should be understood that the drawings introduced below are only for the convenience of clearly describing some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1A schematic diagram of an application scenario of an embodiment of the electronic skin provided by the present invention;

[0039] Figure 2 A schematic structural diagram of an embodiment of the electronic skin provided by the present invention;

[0040] FIG3( a) is a graph showing changes in oxygen and humidity of the temperature sensing unit provided by the present invention;

[0041] FIG3( b ) is a graph showing the change of oxygen and temperature of the humidity sensing unit provided by the present invention;

[0042] FIG3( c ) is a graph showing the change of temperature and humidity of the oxygen sensor unit provided by the present invention;

[0043] FIG4( a ) is a schematic diagram showing the principle of a self-calibration sensor according to an embodiment of the present invention;

[0044] FIG4( b ) is a surface diagram of the temperature calibration of the humidity sensor provided by the present invention;

[0045] FIG4( c ) is a surface diagram of an embodiment of humidity calibration of an oxygen sensor provided by the present invention;

[0046] FIG4( d ) is a surface diagram of another embodiment of humidity calibration of an oxygen sensor provided by the present invention;

[0047] Figure 5 A schematic diagram of the principle of the stretch-insensitive mechanism provided by the present invention;

[0048] FIG6( a ) is a schematic diagram of the bonding strength test results of directly pasting the first material and the second material provided by the present invention;

[0049] FIG6( b ) is a schematic diagram of the bonding strength test results of the first material and the second material DS provided by the present invention;

[0050] FIG6( c ) is a schematic diagram of the bonding strength test results of the first material and the second material after silanization provided by the present invention;

[0051] Figure 7 A schematic diagram showing the comparison of the resistance of the electronic skin provided by the present invention and the bulk hydrogel of the related art under dynamic stretching;

[0052] FIG8( a ) is a response curve of the temperature sensing unit to the gradient temperature under different tensile strains provided by the present invention;

[0053] FIG8( b ) is a resistance change curve at 45° C. under dynamic stretching provided by the present invention;

[0054] FIG8( c ) is a response curve of the humidity sensing unit to the gradient humidity under different tensile strains provided by the present invention;

[0055] FIG8( d ) is a comparison curve of resistance change of a dry finger and a wet finger under dynamic stretching provided by the present invention;

[0056] FIG8( e ) is a response curve of the oxygen sensor unit to gradient oxygen under different tensile strains provided by the present invention;

[0057] FIG8(f) is a diagram of the dynamic stretching of O provided by the present invention. 2 and N 2 Current variation curve;

[0058] Fig. 9 A schematic diagram of a path for implementing the physiological signal monitoring system provided by the present invention;

[0059] FIG10( a ) is a curve showing the effect of wrist movement on humidity response when the sensor is worn on the wrist provided by the present application;

[0060] FIG10( b ) is a curve showing the effect of dynamic stretching on humidity applications such as skin humidity, air humidity, and breathing depth provided by the present application;

[0061] FIG10( c ) is a response change curve of the temperature and humidity sensor unit before and after exercise provided by the present application;

[0062] FIG. 10( d ) is a diagram of a multifunctional sensor used to test TcPO at the wrist provided by the present application. 2 Change curve;

[0063] Fig.11 A schematic diagram of the use scenario and monitoring results of the physiological signal monitoring system provided by the present invention;

[0064] Fig.12 A schematic diagram of the preparation process of the hydrogel film provided by the present invention;

[0065] Fig.13 This is a schematic diagram of the silanization treatment process provided by the present invention. DETAILED DESCRIPTION

[0066] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limitations of the present invention. For the step numbers in the following embodiments, they are only provided for the convenience of explanation, and the order between the steps is not limited in any way, and the execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0067] In the process of chronic disease management, continuous monitoring and data analysis of the condition are crucial. Traditional medical monitoring methods are often limited by time and location, making it difficult to achieve real-time monitoring of the condition. The emergence of portable wearable sensor devices has changed this situation, making it possible to continuously collect patients' physiological information. Doctors can analyze and judge the progress of chronic diseases through real-time collected physiological signal data, and adjust treatment plans in time to achieve the best treatment effect; they can even capture some abnormal signals that are difficult to detect with traditional examination methods, providing important basis for early diagnosis and intervention of diseases. However, wearable sensor devices are mostly rigid structures and are easily interfered by mechanical damage and fail. Therefore, it is necessary to give the sensor flexibility and stretchability so that the device can fit the human skin or clothing surface better, and improve its working stability and reliability when the human body is in motion. In addition, compared with single physiological signal monitoring, combining the monitoring results of multiple physiological signals will provide doctors with more effective information for diagnosing and treating diseases. Among them, body temperature, body surface humidity, exhaled breath humidity and TcPO 2 It is one of the important physiological signals for patients with chronic diseases such as diabetic foot, chronic lower limb severe ischemia and obstructive sleep apnea hypopnea syndrome. Therefore, the development of flexible and stretchable multifunctional physiological signal sensing equipment can monitor and record the changes of relevant signs of patients with chronic diseases in real time, which will effectively assist doctors in disease diagnosis and treatment.

[0068] As one of the largest organs in the human body, the skin has considerable toughness and elasticity, enabling it to withstand various mechanical deformations caused by body movements. Stretchable electronic devices with skin-like mechanical properties can adapt to irregular surfaces and withstand various deformations. In addition, the skin contains many receptors that encode environmental stimuli and can sense pressure, temperature and humidity, thereby establishing a connection between the individual and its surroundings. In order to replicate the somatosensory function of human skin, researchers are focusing on developing skin-like multifunctional sensors that can detect various forms of stimuli. In the past few decades, researchers have developed devices that can integrate multiple sensing modes for applications in robotics, health monitoring, artificial intelligence and the Internet of Things. A range of materials have been used to make skin-like multifunctional sensors, including nanostructured metals, carbon nanotubes, conductive polymers, two-dimensional materials and hydrogels. Among them, conductive hydrogel is a promising candidate. The functionalized hydrogel has ionic conductivity, and the electrical parameters can be directly used as the response signal to facilitate signal acquisition; it has high stretchability and can fit various irregular surfaces such as the human body, improving the comfort and practicality of wearing; it has multiple sensitivities and can achieve multifunctional sensing; it also has high transparency and can be used in military operations that require stealth or improve the aesthetics of wearing. However, mechanical deformation changes the conductivity of most hydrogels, affecting the stability and accuracy of hydrogel-based sensors. The different sensitivities of hydrogels can lead to crosstalk problems, complicating the accurate and simultaneous detection of multiple complex stimuli. Therefore, there is a need to develop stretch-insensitive, crosstalk-free, multifunctional flexible sensing devices to achieve stable monitoring of patient physiological signals.

[0069] The stretchability and multiple sensitivities of hydrogels bring convenience, but also bring problems such as interference with response signals and crosstalk between multiple stimuli. Many methods have been developed to mitigate the effects of strain, including serpentine, spiral and wrinkled structures, as well as composite materials. However, existing structural and material designs are either too complex or insufficient in effectively isolating strain. The island-bridge parallel structure is another way to minimize strain interference. Local stiffness affects the strain distribution during stretching, and increasing the stiffness of a specific area can help isolate the effect of strain on device performance. However, modulus mismatch often leads to separation between island bridge regions, resulting in structural damage and device failure.

[0070] The coupling interference of multiple signals makes it difficult to achieve high sensitivity and high selectivity detection of different stimuli by multifunctional sensors. Researchers have explored different methods to solve and minimize the crosstalk problem associated with multiple stimuli. For example, encapsulation can help isolate the effects of ambient humidity and gas on sensing, but it may not be suitable for humidity and gas sensing itself. Creating unique sensing mechanisms for specific stimuli can help distinguish various sources of stimulation. However, due to the aqueous nature of hydrogels, it is difficult to exclude the effects of ambient humidity on sensing. Therefore, effectively solving the crosstalk problem poses a major obstacle to multifunctional sensing in hydrogels.

[0071] Therefore, it is necessary to develop a multifunctional stretchable sensor that can simultaneously monitor multiple target physiological signals and is not affected by tensile strain, so as to achieve convenient monitoring of human health or comfort in medical environments.

[0072] The electronic skin according to the embodiment of the present invention is described in detail below with reference to the accompanying drawings. Figure 1 and attached Figure 2 An electronic skin proposed according to an embodiment of the present invention is described, comprising: a sensing platform, and a plurality of sensing units arranged on the sensing platform;

[0073] The sensing platform is an island bridge structure, and comprises a first material and a second material, wherein the first material is a stretchable material and the second material is a non-stretchable material; the sensing platform is made by bonding the second material to the first material after silanization treatment; and the sensing unit is arranged on the second material;

[0074] The sensing unit comprises a sensitive film and an electrode, and is used to measure temperature, humidity or oxygen.

[0075] Reference Figure 1 As shown, the electronic skin in the embodiment of the present application can measure a variety of human body signals to monitor human health. Figure 1 In the process, the electronic skin is worn on the wrist, data is collected through hardware circuits, transmitted wirelessly to the host computer / server for data processing, and displayed on the terminal.

[0076] Optionally, in the electronic skin of the embodiment of the present invention, the sensing platform is a three-layer structure, the first layer is used to measure the humidity and oxygen in the air, the second layer is used to measure the body temperature of the object, and the third layer is used to measure the humidity and TcPO of the skin surface when contacting the skin surface of the object. 2 concentration.

[0077] In some possible implementations, of course, the present application does not limit the specific structure of the sensing platform, and those skilled in the art may make adjustments according to actual needs.

[0078] Optionally, in the electronic skin in the embodiment of the present invention, the first material includes PDMS, the second material includes PET, and the sensitive film includes a PAM / Carr-LiBr hydrogel film.

[0079] In some possible implementations, the present application does not limit the specific types of the first material, the second material, and the sensitive film.

[0080] In another aspect, the present invention provides a method for realizing electronic skin, which is used to prepare the above-mentioned electronic skin, comprising:

[0081] Take a number of metal sheets, and prepare a first material film on the metal sheets as a substrate;

[0082] Performing silanization treatment on the cut second material film to obtain a plurality of islands;

[0083] The islands are bonded to the substrate, electrodes are fixed on each island and covered with a sensitive film to obtain the electronic skin.

[0084] Optionally, in the method for realizing the electronic skin in the embodiment of the present invention, the step of performing silanization treatment on the cut second material film to obtain a plurality of islands comprises:

[0085] Cleaning the surface of the second material film with deionized water and isopropyl alcohol, and performing air plasma treatment for a first time period;

[0086] Immersing the treated second material film in an APTES solution and heating it at a first temperature for a second period of time to perform a silanization treatment;

[0087] The second material film was taken out, rinsed with deionized water and blown dry with a nitrogen gun to obtain several islands.

[0088] Optionally, in the method for realizing the electronic skin in the embodiment of the present invention, the step of bonding the island to the substrate comprises:

[0089] performing air plasma treatment on the surface of the first material film and the second material film after silanization for a third time period;

[0090] The first material film and the second material film that have been bonded are bonded with Dragon skin prepolymer and cured at a second temperature for a fourth period of time to obtain a sensing platform.

[0091] Optionally, in the method for realizing electronic skin in an embodiment of the present invention, the sensitive film includes a PAM / Carr-LiBr hydrogel film, and the PAM / Carr-LiBr hydrogel film is prepared by the following steps:

[0092] Weighing acrylamide, carrageenan, N-methylenebisacrylamide, potassium chloride, a photoinitiator, and deionized water in a preset ratio, heating in an oil bath at a third temperature for a fifth time to obtain a precursor solution;

[0093] preparing a PDMS prepolymer, spin coating the PDMS prepolymer on an aluminum sheet at a preset speed, and after curing, plasma treating the PDMS surface for a sixth period of time;

[0094] Dropping the precursor solution on the plasma-treated PDMS, and spin coating the PDMS to obtain a thin precursor layer;

[0095] After the precursor thin layer is refrigerated, a LiBr solution is drop-coated on the surface of the precursor thin layer, and the precursor thin layer is placed under an ultraviolet lamp for photoinitiation to obtain a PAM / Carr-LiBr hydrogel film.

[0096] Optionally, in the method for realizing electronic skin in an embodiment of the present invention, the sensitive film includes an ion gel film, and the ion gel film is prepared by the following steps:

[0097] An ion gel precursor solution was prepared by acetone;

[0098] The ion gel precursor solution is poured onto an aluminum substrate and kept for a seventh period of time to obtain an ion gel after the solvent is completely evaporated.

[0099] Optionally, in the method for implementing electronic skin in an embodiment of the present invention, the electronic skin is measured by the following steps:

[0100] Measuring a first temperature, a first humidity, and a first oxygen through the electronic skin;

[0101] Determine that the first temperature is a temperature measurement result, and decouple the first humidity according to the temperature measurement result to obtain a humidity measurement result;

[0102] The first oxygen is decoupled according to the temperature measurement result and the humidity measurement result to obtain an oxygen measurement result.

[0103] It can be seen that the contents of the above-mentioned electronic skin embodiments are all applicable to the embodiments of the present method, the functions specifically implemented by the embodiments of the present method are the same as those of the above-mentioned electronic skin embodiments, and the beneficial effects achieved are also the same as those achieved by the above-mentioned electronic skin embodiments.

[0104] On the other hand, an embodiment of the present invention provides a physiological signal monitoring system, including: the electronic skin as described above, a control module, and a wireless module;

[0105] The control module is used to send a control signal to enable the electronic skin to measure temperature, humidity or oxygen, obtain a measurement signal, process the measurement signal, and send the processed measurement signal to the target terminal through the wireless module.

[0106] Similarly, the contents of the above method embodiments are applicable to the monitoring system embodiments. The functions specifically implemented by the monitoring system embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0107] The electronic skin, the method for realizing the electronic skin and the physiological signal monitoring system provided by the present application are described in detail below with a specific embodiment:

[0108] The application products of this technology include physiological signal sensors and chronic disease treatment devices.

[0109] The multifunctional physiological signal monitoring electronic skin of the present invention firstly utilizes a sensitive film material with multiple sensitivities (i.e., the sensitive film in the present application, such as a hydrogel film and an ion gel film) to monitor temperature, humidity and oxygen. 2Stimulus signals such as PDMS and ETC are monitored in real time. At the same time, self-calibration sensing between multiple stimuli is achieved by combining different sensing mechanisms with physical isolation. In addition, a rigid and flexible "island bridge" structure is designed by using materials A and B with a large modulus difference to effectively isolate the signal interference caused by tensile strain and bending. Among them, material A has a small modulus (i.e., the first material of this application), and is usually flexible and stretchable, such as polydimethylsiloxane (PDMS), platinum-catalyzed silica gel (Ecoflex), hydrogenated styrene-butadiene block copolymer (Styrene Ethylene Butylene Styrene, SEBS) and other materials; material B (i.e., the second material of this application) has a large modulus and is usually a non-stretchable rigid material, such as polyethylene terephthalate (PET), ABS plastic (Acrylonitrile Butadiene Styrene plastic), polymethyl methacrylate (PMMA) and other materials. In addition, silanization treatment is used to strengthen the chemical anchoring between materials A and B, reducing the risk of structural failure caused by modulus mismatch. The present invention uses PDMS (material A) and PET (material B) as example materials for island bridge structures, and polyacrylamide / κ-carrageenan-LiBr (PAM / Carr-LiBr) hydrogel film as an example material for sensitive films. Finally, a Bluetooth multi-channel sensing circuit is designed and developed, and a multifunctional sensor is combined with it to form a multifunctional wireless physiological signal sensing electronic skin system (such as Figure 1 The whole system consists of three parts: multifunctional sensor, wireless transmission circuit and signal receiving terminal. The system can monitor body temperature, surface humidity, respiration, transcutaneous oxygen partial pressure (TcPO 2 ) and other physiological signals in real time, and transmit the sensor data to the mobile terminal for display in real time. It is expected to be used for non-invasive diagnosis and treatment of chronic diseases such as diabetic foot, chronic lower limb severe ischemia and obstructive sleep apnea hypopnea syndrome, monitor the progression of the disease, and assist in the treatment of chronic diseases.

[0110] The structural schematic diagram of the strain-insensitive multifunctional electronic skin of the present invention is as follows: Figure 2 As shown, it includes a strain-insensitive sensing platform and six sensing units (it can be understood that the number of sensing units can be adjusted. Figure 2For illustrative purposes). Each sensing unit consists of a layer of PAM / Carr-LiBr film (i.e., sensitive film) and two electrode wires. Different electrodes and applied voltages are selected according to different target stimulus sources to preliminarily isolate different physiological signals in the sensing mechanism. For the temperature sensing unit, Ag wire is used as the electrode of the sensing unit, and an AC signal with an amplitude of 1V and a frequency of 1kHz is applied between the two electrodes; for the humidity sensing unit, the electrode is also an Ag wire, and an AC signal with an amplitude of 0.5V and a frequency of 200Hz is applied between the two electrodes; for 2 The cathode and anode of the sensing unit are both Ag wires, and a 0.5V DC signal is applied. That is, in the embodiment of the present application, the electrode is set to be a first metal, and a first signal is added between the electrodes so that the electrode is used to measure temperature; the electrode is set to be a second metal, and a second signal is added between the electrodes so that the electrode is used to measure humidity; the electrode is set to be a third metal, and a third signal is added between the electrodes so that the electrode is used to measure oxygen. The first signal and the second signal are AC signals, and the third signal is a DC signal. The sensing platform has three layers in total. The first layer is used to prepare humidity and O 2 The sensor unit can be used to detect the humidity and oxygen content in the air; the second layer is used to prepare the temperature sensor unit, which can be used to detect changes in human body temperature; the third layer is also used to prepare the humidity and oxygen content in the air. 2 The sensor unit is placed with two sensor units facing outwards. When worn on the skin surface, it can be used to monitor epidermal moisture and TcPO 2 The first and third layers of PDMS can be used to physically isolate humidity and O 2 The multifunctional sensor was placed in a nitrogen background and purged with 50% O 2 After that, the conductivity of the temperature sensing unit did not change significantly ( Figure 3a curve in the upper middle figure). Figure 3a The curve in the middle and lower figure shows that when the humidity decreases from 75% RH to 33% RH, the conductance of the temperature sensing unit does not change significantly. Figure 3a Description of the temperature sensing unit 2 It is insensitive to temperature and humidity, and its temperature sensing is resistant to interference from other stimuli. Figure 3b The curve in the upper middle figure shows that the humidity sensor unit is not sensitive to oxygen. However, when the ambient temperature changes, the response change of the humidity sensor unit will be affected by the temperature ( Figure 3b curve in the lower middle figure). Figure 3b It was shown that the humidity sensing unit was resistant to the interference of oxygen, but its conductance was affected by temperature. Figure 3c The curves in the upper middle figure show the multifunctional sensor in nitrogen atmosphere at different temperatures and 10% O 2 The response curves do not overlap, indicating that O2 The sensing unit is affected by the ambient temperature. Figure 3c The curve in the lower middle figure is O 2 The sensor unit responds to 10% O at different humidity levels 2 As the humidity decreases, O 2 The response degree of O 2 The sensing unit is disturbed by the surrounding humidity. Figure 3c Explain O 2 The sensing unit is affected by both ambient temperature and humidity. Therefore, temperature sensing is not affected by the other two stimuli, humidity sensing is only affected by temperature, and oxygen sensing is affected by both temperature and humidity. Therefore, we can use the temperature that can be accurately measured to calibrate the humidity sensing unit that is affected by temperature; and then use the temperature and humidity sensing units to calibrate the oxygen sensing unit, so as to achieve self-calibration and crosstalk-free sensing between multiple stimuli, such as Figure 4a By testing the response of the SSIM sensor to gradient humidity at different temperatures, the temperature detection results can be used to Figure 4b The temperature-humidity response composite diagram shown decouples humidity-related information. Test the gradient O under different temperature and humidity conditions 2 The response of concentration, combined with the test results of temperature and humidity, is analyzed by humidity-O 2 Responding to composite graphs can decouple O 2 Concentration related information ( Figure 4c and Figure 4d ).

[0111] The mechanism of the multifunctional electronic skin in the present invention to achieve strain-insensitive sensing is as follows Figure 5 As shown. An island-bridge structure sensing platform was prepared using PDMS and PET, and the sensing unit was made in the PET island area. When the device is stretched in a certain direction, the length of the bridge area increases along the stretching direction, while the size of the island area remains unchanged. The sensing unit on the island area can still work normally without being disturbed by the stretching, thus achieving stretch insensitivity. However, the island area is prone to falling off due to the modulus mismatch with the bridge area. Therefore, the combination of the island area and the bridge area is crucial, which is related to whether the island-bridge structure can remain stable in various stretches and movements. As shown Figure 6a As shown in the figure, when PET and PDMS are directly bonded together, there is only a simple physical interaction between the two, which is very easy to fall off. By introducing Dragon Skin (DS) as a binder between PET and PDMS, the bonding between the island area and the bridge area is improved, and the PET island area will not fall off during normal stretching. However, after the island area is pulled up several times with tweezers, PET still separates from PDMS ( Figure 6b). Therefore, we functionalized the PET surface by grafting functionalized silane (3-aminopropyl)-triethoxysilane (APTES). Then, PET and PDMS were treated with air plasma to introduce hydroxyl groups on their surfaces, and then the two were bonded together with DS. At this time, covalent siloxane bonds were formed between DS and PET and PDMS, and the bond was tighter. Using tweezers to pull the PET multiple times will not cause the island area to fall off ( Figure 6c ). Comparison of the adhesion energy between PET and PDMS under three adhesion methods. The adhesion energy after silanization treatment is as high as 300 Jm -2 The resistance changes of bulk PAM / Carr-LiBr hydrogel and the multifunctional sensor of the present invention under dynamic stretching at a strain level of 50% were compared. Figure 7 The middle right picture is Figure 7 The enlarged box part of the middle left figure. It can be seen that the resistance of the bulk hydrogel changes with repeated stretching, indicating that the electrical signal of the hydrogel is easily affected by tensile strain. The resistance of the multifunctional sensor of the present invention remains unchanged under dynamic stretching, indicating that it has a very high ability to resist the interference of tensile strain. Thanks to the island bridge structure, the operation of the sensor can resist the interference of tensile strain. Under 0%, 25% and 50% strain conditions, the sensor is sensitive to temperature, humidity and O 2 Still able to sense normally ( Figure 8a , Figure 8c , Figure 8e ). The response curves under the three stretching states are almost the same, indicating that the sensor's sensitivity is not affected by the degree of stretching. In actual use, the tensile strain encountered by the device is often dynamic rather than static. The sensor is alternately placed in a static state of 0% Strain and a dynamic stretching state of 50% strain. When the 45°C heating plate repeatedly approaches the temperature sensing unit, the degree of resistance change is consistent whether it is in a static state or a 50% strain dynamic stretching state ( Figure 8b ). When a dry finger is placed close to the humidity sensing unit, the change in resistance under 50% strian dynamic stretch is almost the same as that under 0% strian ( Figure 8d ). 2 Blow N near the sensor unit 2 and O 2 , the trend and size of the current change are basically the same. These test results show that the SSIM sensor's sensing of temperature, humidity and oxygen is not affected by the degree of stretching or the interference of dynamic stretching. It has the ability to stably record response signals under various stretching motion states. Figure 8 proves that each sensor is not affected by the degree of stretching and dynamic stretching. Figure 8aIt is the response curve of the temperature sensing unit to the gradient temperature under different tensile strains; Figure 8b Figure 8(c) is the resistance change of the humidity sensor unit to the gradient temperature under 50% stretching; Figure 8(d) is the resistance change of the dry finger and the wet finger under 50% stretching (Figure 8(e)). The oxygen sensor unit is the resistance change of the oxygen sensor unit to the gradient temperature under 50% stretching (Figure 8(f)). 2 and N 2 The current changes.

[0112] Figure 10 shows the sensor's detection of some physiological signals. The sensor is worn on the wrist, and a dry finger and a wet finger are placed close to the humidity sensing unit ( Fig.10a ). Regardless of the wrist position, the sensor can accurately detect the approach of a finger and distinguish the moisture level of the finger epidermis, demonstrating its potential for joint applications. Fig.10b As shown, when the sensor is in its original state, a dry finger is brought close to the humidity sensing unit. Subsequently, the sensor enters a 50% strain dynamic stretching state. A dry finger and a wet finger are brought close to the sensing unit in turn, and then a desiccant and a humidifier are brought close to the sensing unit. The resistance change of the humidity sensing unit is continuously recorded. The results show that even under dynamic stretching, the sensor can still detect the approach of the finger and distinguish the degree of wetness on the surface of the finger. It can also distinguish the changes in ambient humidity caused by the desiccant and the humidifier. These results show that the sensor's response to humidity is also not affected by dynamic stretching. In addition, the humidity sensing unit can also distinguish between shallow breathing and deep breathing in the state of dynamic stretching, demonstrating its potential for application in respiratory monitoring ( Fig.10b ). Based on the multi-stimulus response function, the sensor can also monitor human body temperature and skin humidity at the same time, such as Fig.10cAs shown. When the sensor is worn on the inside of the arm, the temperature and humidity sensing unit generates a response signal, sensing the body temperature and skin humidity at this time. When the wearer starts to exercise, the relative conductance of the temperature and humidity sensing unit begins to increase, indicating that the body temperature rises due to exercise and the humidity of the skin surface increases due to sweating. When the wearer stops exercising, the relative conductance of the temperature and humidity sensing unit first increases and then decreases. This shows that after stopping exercise, the wearer's body temperature is still rising and the skin continues to sweat. After a period of time, the body temperature and skin surface humidity reach a peak, and then the body gradually returns to its original state. The signal changes detected by the sensor are consistent with the changes in body temperature and skin humidity before and after human exercise, indicating that the sensor made in this project has the ability to monitor human physiological signals and has the potential for application in outdoor sports and health testing. In addition, we can also use this multifunctional sensor to monitor TcPO on the skin surface. 2 First, wear the sensor on the inside of the wrist, then wrap the wrist with a heating sheet to promote oxygen overflow from the skin surface, then remove the heating sheet to obtain TcPO 2 Change information, such as Fig.10d As shown, the temperature sensing unit excludes O 2 The sensor unit monitors TcPO 2 Temperature disturbance

[0113] The system block diagram of the Bluetooth multi-channel sensing circuit of the present invention is as follows: Fig. 9 As shown. The wireless circuit powers the sensor, and converts the sensor's output electrical signal into a voltage signal through amplification, filtering, and lifting through the signal conditioning module, and then collects it through the microprocessor's analog-to-digital converter. The microprocessor packages and encodes the collected data and transmits it to the wireless transmission circuit through the serial port, which then sends it to the user terminal APP. This project uses the low-power STM32 series chip as the microprocessor and the small-volume SMD EFR32BG22 chip as the wireless transmission module. The entire system is powered by a 3.7V lithium battery, and the power supply voltage 3.7V is converted to other voltages through a DC-DC power supply chip to drive different chips and circuit modules.

[0114] like Fig.11 As shown, patients can wear the sensor at any desired location, and the wireless circuit will collect the body temperature, body surface humidity, respiratory status, TcPO 2 The sensor signals will be transmitted to the mobile phone APP in real time via Bluetooth. These data will be directly stored on the mobile phone for review during diagnosis and treatment. Specific implementation 1:

[0116] Preparation of hydrogel film: Weigh 15g acrylamide, 3g κ-type carrageenan, 0.01g N,N-methylenebisacrylamide, 0.18g potassium chloride, 0.2g photoinitiator and 82mL deionized water respectively and add them into a 100mL flask (the preparation amount can be adjusted according to the proportion). Heat in a 96℃ oil bath for 5 hours, and stir the mixed solution at 600rpm to obtain a PAM / Carr precursor solution. Take Dow Corning 184 and 184 curing agent in a ratio of 10:1 in a plastic cup, and perform homogenization for 60 seconds to obtain a PDMS prepolymer. Fig.12 As shown, take several 5×5cm aluminum sheets, spin-coat 2g of PDMS prepolymer on the aluminum sheets at a speed of 400rpm for 30s. After curing, the PDMS surface is treated with plasma at a power of 120W for 5 minutes. Take about 5mL of PAM / Carr precursor solution and drop it on the plasma-treated PDMS. Spin-coat at a speed of 600rpm for 25s to obtain a precursor thin layer. The precursor thin layer is then placed in a refrigerator at 6°C for 1 hour, and the first network of κ-type carrageenan is formed under the action of potassium ions. Then, about 2mL of 50wt% LiBr solution is dripped on the surface of the precursor film, and placed under a UV lamp for photoinitiation for 2 hours to obtain a PAM / Carr-LiBr hydrogel film.

[0117] Preparation of ion gel film: The ion gel was prepared using a one-pot method. First, 0.543 g of PVDF-HFP, 1.125 g of IL (Emisfsi) and 14 ml of acetone were added to a beaker. In order to evenly disperse the chemical substances, the solution was stirred at 1000 rpm / min for 5 hours at 25°C. Acetone is a solvent for the polymer. After stirring, a flowable ion gel precursor solution is obtained, which is poured onto an aluminum substrate and stored at 40°C for 12 hours. After the solvent is completely volatilized, an ion gel is obtained. By changing the weight ratio of polymer to ionic liquid, ion gels with different properties can be obtained. Specific implementation 2:

[0119] Preparation of multifunctional sensors. Take several 5×5 cm aluminum sheets and prepare multiple PDMS films as flexible stretchable substrates. Cut 0.2 mm thick PET into 6×6 mm sheets as islands. Clean the PET surface with deionized water and isopropanol, and treat it with air plasma for 1 minute. Immerse the treated PET in a 5% APTES solution and heat it at 80°C for 5 minutes for silanization. Take out the PET sheet, rinse it with deionized water and blow dry it with a nitrogen gun. Perform air plasma treatment on the PDMS and silanized PET surfaces for 1 min 10s. Use Dragon skin prepolymer to bond PET and PDMS, and cure it at 100°C for 30 minutes to obtain a SIIM sensing platform. The preparation process is as follows Fig.13Then, the electrodes were fixed to the two ends of the PET island using transparent tape, and then the PAM / Carr-LiBr hydrogel film was covered on top to form a sensing unit.

[0120] This application uses an island-bridge structure to design a stretch-insensitive multifunctional sensing platform, and uses silanization treatment of PET to enhance the chemical anchoring between the PET island area and the PDMS bridge area, thereby enhancing the stability of the island-bridge structure. This application's self-calibrated multimodal flexible sensing further stabilizes the island-bridge structure and effectively isolates the interference of stretching on flexible sensing. While achieving multifunctional sensing, it is possible to isolate crosstalk between various stimulus sources through self-calibration.

[0121] It is understandable that the tensile strain that the device is subjected to in real time can be sensed by integrating strain sensors, and then the sensors can be calibrated to eliminate the influence of stretching on the sensors. However, this will bring a greater workload to the device, especially when multiple sensors are integrated on the same sensing platform, the complexity will increase several times.

[0122] In some selectable embodiments, the function / operation mentioned in the block diagram may not occur in the order mentioned in the operation diagram. For example, depending on the function / operation involved, the two boxes shown in succession can actually be executed substantially simultaneously or the boxes can sometimes be executed in reverse order. In addition, the embodiment presented and described in the flow chart of the present invention is provided by way of example, for the purpose of providing a more comprehensive understanding of technology. The disclosed method is not limited to the operation and logic flow presented herein. Selectable embodiments are expected, wherein the order of various operations is changed and the sub-operation of a part for which is described as a larger operation is performed independently.

[0123] In addition, although the present invention is described in the context of functional modules, it should be understood that, unless otherwise specified, one or more of the functions and / or features can be integrated into a single physical device and / or software module, or one or more functions and / or features can be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding the present invention. More specifically, in view of the properties, functions and internal relationships of the various functional modules in the device disclosed herein, the actual implementation of the module will be understood within the conventional skills of the engineer. Therefore, those skilled in the art can implement the present invention set forth in the claims without excessive experimentation using ordinary techniques. It is also understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of the present invention, which is determined by the full scope of the appended claims and their equivalents.

[0124] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several programs to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0125] The logic and / or steps represented in the flowchart or otherwise described herein, for example, may be considered as an ordered list of executable programs for implementing the logical functions, and may be embodied in any computer-readable medium for use by a program execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch and execute a program from a program execution system, device or apparatus), or in conjunction with such program execution systems, devices or apparatuses. For purposes of this specification, a "computer-readable medium" may be any device that can contain, store, communicate, propagate or transmit a program for use by a program execution system, device or apparatus, or in conjunction with such program execution systems, devices or apparatuses.

[0126] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0127] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable program execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0128] In the above description of this specification, the description with reference to the terms "one embodiment / example", "another embodiment / example" or "certain embodiments / examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0129] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

[0130] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. An electronic skin, characterized in that: The electronic skin comprises: a sensing platform, and a plurality of sensing units arranged on the sensing platform; The sensing platform is an island bridge structure, and comprises a first material and a second material, wherein the first material is a stretchable material and the second material is a non-stretchable material; the sensing platform is made by bonding the second material to the first material after silanization treatment; and the sensing unit is arranged on the second material; The sensing unit comprises a sensitive film and an electrode, and is used to measure temperature, humidity or oxygen.

2. The electronic skin according to claim 1, characterized in that: The sensing platform has a three-layer structure, the first layer is used to measure the humidity and oxygen in the air, the second layer is used to measure the body temperature of the object, and the third layer is used to measure the humidity and TcPO2 concentration of the skin surface when contacting the skin surface of the object.

3. The electronic skin according to claim 1, characterized in that: The first material includes PDMS, the second material includes PET, and the sensitive film includes a PAM / Carr-LiBr hydrogel film.

4. A method for realizing electronic skin, characterized in that: The method is used to prepare the electronic skin according to any one of claims 1 to 3, and the method comprises: Take a number of metal sheets, and prepare a first material film on the metal sheets as a substrate; Performing silanization treatment on the cut second material film to obtain a plurality of islands; The islands are bonded to the substrate, electrodes are fixed on each island and covered with a sensitive film to obtain the electronic skin.

5. The method for realizing electronic skin according to claim 4, characterized in that: The cut second material film is subjected to silanization treatment to obtain a plurality of islands, including: Cleaning the surface of the second material film with deionized water and isopropyl alcohol, and performing air plasma treatment for a first time period; Immersing the treated second material film in an APTES solution and heating it at a first temperature for a second period of time to perform a silanization treatment; The second material film was taken out, rinsed with deionized water and blown dry with a nitrogen gun to obtain several islands.

6. The method for realizing electronic skin according to claim 4, characterized in that: The step of bonding the island to the substrate comprises: performing air plasma treatment on the surface of the first material film and the second material film after silanization for a third time period; The first material film and the second material film that have been bonded are bonded with Dragon skin prepolymer and cured at a second temperature for a fourth period of time to obtain a sensing platform.

7. The method for realizing electronic skin according to claim 4, characterized in that: The sensitive film comprises a PAM / Carr-LiBr hydrogel film, and the PAM / Carr-LiBr hydrogel film is prepared by the following steps: Weighing acrylamide, carrageenan, N-methylenebisacrylamide, potassium chloride, a photoinitiator, and deionized water in a preset ratio, heating in an oil bath at a third temperature for a fifth time to obtain a precursor solution; preparing a PDMS prepolymer, spin coating the PDMS prepolymer on an aluminum sheet at a preset speed, and after curing, plasma treating the PDMS surface for a sixth period of time; Dropping the precursor solution on the plasma-treated PDMS, and spin coating the PDMS to obtain a thin precursor layer; After the precursor thin layer is refrigerated, a LiBr solution is drop-coated on the surface of the precursor thin layer, and the precursor thin layer is placed under an ultraviolet lamp for photoinitiation to obtain a PAM / Carr-LiBr hydrogel film.

8. The method for realizing electronic skin according to claim 4, characterized in that: The sensitive film comprises an ion gel film, and the ion gel film is prepared by the following steps: An ion gel precursor solution was prepared by acetone; The ion gel precursor solution is poured onto an aluminum substrate and kept for a seventh period of time to obtain an ion gel after the solvent is completely evaporated.

9. The method for realizing electronic skin according to claim 4, characterized in that: The electronic skin is measured by the following steps: Measuring a first temperature, a first humidity, and a first oxygen through the electronic skin; Determine that the first temperature is a temperature measurement result, and decouple the first humidity according to the temperature measurement result to obtain a humidity measurement result; The first oxygen is decoupled according to the temperature measurement result and the humidity measurement result to obtain an oxygen measurement result.

10. A physiological signal monitoring system, characterized in that: include: The electronic skin, control module, and wireless module as claimed in any one of claims 1 to 3; The control module is used to send a control signal to enable the electronic skin to measure temperature, humidity or oxygen, obtain a measurement signal, process the measurement signal, and send the processed measurement signal to the target terminal through the wireless module.

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