Preparation method of MC-TENG sensor and blood pressure monitoring system

Abstract

The invention discloses a preparation method of an MC-TENG sensor and a blood pressure monitoring system. The method comprises the following steps: providing a substrate, and paving PDMS on the substrate; laying a porous membrane on the PDMS, and carrying out curing treatment to form a cavity; coating the cavity with a composite material, and carrying out spin coating treatment so that the cavity is filled with the composite material; scraping off the composite material on the surface of the porous membrane, and carrying out curing treatment; stripping the porous membrane from the PDMS, overturning, and spreading on a metal substrate; cleaning through plasma etching to form a micron column structure; the surface of the micron column structure is covered with a metal layer, and the micron column structure and a friction layer are assembled through cutting treatment to form the MC-TENG sensor. According to the embodiment of the invention, the preparation cost is reduced, and the application universality of the TENG sensor is promoted. The method can be widely applied to the technical field of blood pressure measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of blood pressure measurement, and in particular to a method for preparing a MC-TENG sensor and a blood pressure monitoring system. Background Art

[0002] Current blood pressure monitoring methods have limitations; among them, electrocardiographs, cardiac ultrasound, and intravenous cannulation are accurate, but they are bulky and require professional operation, and are not suitable for home use; cuff-type blood pressure monitors have been proven to be accurate and practical, but they rely on compression of blood vessels for measurement, which may make patients feel uncomfortable, so non-invasive and convenient monitoring solutions are needed. In one embodiment, a PPG sensor is used to detect pulse waves in the peripheral area of ​​the body, but this solution is susceptible to external light interference, skin color changes, and other environmental factors, which may affect the accuracy of blood pressure. Other embodiments use piezoresistive sensors to sense peripheral pulse waves of the body, but these sensors require external power supply to generate electrical signals, which increases the power consumption of wearable devices. Other embodiments use triboelectric nanogenerator (TENG) sensors, which can directly generate electrical signals under external loads, achieving efficient detection and recording. In related technologies, complex microstructures are usually prepared by photolithography technology to improve monitoring sensitivity, which has high costs and is not conducive to the widespread use of TENG sensors. Summary of the invention

[0003] 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.

[0004] To this end, the purpose of the present invention is to provide a low-cost MC-TENG sensor preparation method and a blood pressure monitoring system.

[0005] In order to achieve the above technical objectives, the technical solutions adopted by the embodiments of the present invention include the following aspects:

[0006] On the one hand, an embodiment of the present invention provides a method for preparing a MC-TENG sensor, comprising: providing a substrate, and laying PDMS on the substrate; laying a porous membrane on the PDMS, and performing a curing treatment to form a cavity; applying a composite material on the cavity, and performing a spin coating treatment so that the composite material fills the cavity; the composite material comprises CNT and PDMS; scraping off the composite material on the surface of the porous membrane, and performing a curing treatment; peeling the porous membrane from the PDMS, flipping it over and laying it on a metal substrate; cleaning it by plasma etching to form a micron column structure; covering the surface of the micron column structure with a metal layer, and assembling it with a friction layer by cutting to form a MC-TENG sensor. The embodiment of the present application prepares the MC-TENG sensor by synergistically combining a porous membrane template and plasma etching; it is beneficial to reduce the preparation cost and promote the wide application of TENG sensors.

[0007] In addition, the method for preparing the MC-TENG sensor according to the above embodiment of the present invention may also have the following additional technical features:

[0008] Furthermore, in the preparation method of the MC-TENG sensor of the embodiment of the present invention, the porous membrane includes a PET porous membrane, and the parameters of the PET porous membrane that need to be determined include: the pore size of the PET porous membrane is 450nm to 20um; the density of the PET porous membrane is 4x10 4 Up to 1x10 8 Pieces / cm 2 .

[0009] Further, in one embodiment of the present invention, the parameters that need to be determined for the plasma etching include: an oxygen gas flow rate of 90 to 110 mL / min; an RF radio frequency power of 90 to 110 W; and the method further includes:

[0010] The longer the etching time, the higher the height of the formed micron pillars;

[0011] The required etching time is inversely proportional to the power of the RF radio frequency; the required etching time is inversely proportional to the oxygen gas flow rate.

[0012] Further, in one embodiment of the present invention, the MC-TENG sensor is formed by assembling the friction layer, comprising:

[0013] On the substrate of the micron column structure, electrode wires are connected by heating and pressurizing to form a positive friction layer;

[0014] Another porous membrane is taken, and a metal layer is covered on the surface of the porous membrane to make a negative triboelectric layer electrode;

[0015] A negative friction layer material FEP is inserted between the positive friction layer and the negative friction electric layer electrode to encapsulate into a MC-TENG sensor.

[0016] Furthermore, in one embodiment of the present invention, the weight ratio of CNT to PDMS in the composite material is 0 to 1 / 8, and the output performance of the MC-TENG sensor increases with the increase of the CNT specific gravity; the parameters of the spin coating process include: the spin coating speed is 500r / min to 2000r / min, and the spin coating time is 60s to 300s.

[0017] On the other hand, an embodiment of the present invention provides a blood pressure monitoring system, including:

[0018] The MC-TENG sensor prepared by the above-mentioned method for preparing the MC-TENG sensor is used to obtain the pulse wave signal of the monitored object;

[0019] An analog front-end module, used for acquiring an ECG signal of the monitored object;

[0020] The control module is used to collect the pulse wave signal and the ECG signal, and determine the blood pressure of the monitored object based on the pulse wave signal and the ECG signal.

[0021] Furthermore, in the blood pressure monitoring system of the embodiment of the present invention, the control module is also used for:

[0022] According to the reference blood pressure value measured by the cuff sphygmomanometer, a corresponding relationship with the reference pulse wave transmission time is established to complete the calibration of the blood pressure measurement of the same test subject by the blood pressure monitoring system;

[0023] The pulse transmission time of the blood pressure to be measured is determined based on the pulse wave signal and the ECG signal over a period of time, and the blood pressure of the monitored object is determined based on the reference blood pressure value and the reference pulse wave transmission time.

[0024] Furthermore, the blood pressure monitoring system of the embodiment of the present invention further includes:

[0025] an amplifier circuit, used to amplify the pulse wave signal measured by the MC-TENG sensor;

[0026] The amplification circuit includes an operational amplifier, the MC-TENG sensor is connected to the inverting input terminal of the operational amplifier, and the inverting input terminal of the operational amplifier is connected to the output terminal of the operational amplifier through a resistor and a capacitor; the first power supply is connected to the non-inverting input terminal of the operational amplifier through a first resistor, and the non-inverting input terminal of the operational amplifier is grounded through a second resistor.

[0027] Furthermore, the blood pressure monitoring system of the embodiment of the present invention further includes:

[0028] A terminal, used for displaying the pulse wave signal, the ECG signal, the blood pressure value and the change curve;

[0029] The Bluetooth module is used for data transmission between the control module and the terminal.

[0030] On the other hand, an embodiment of the present invention provides a MC-TENG sensor, which is prepared by the preparation method of the MC-TENG sensor as described above and is used in the blood pressure monitoring system as described above.

[0031] The method provided by the embodiment of the present invention includes: providing a substrate, and laying PDMS on the substrate; laying a porous membrane on the PDMS, and curing it to form a cavity; applying a composite material on the cavity, and spin coating it so that the composite material fills the cavity; the composite material includes CNT and PDMS; scraping off the composite material on the surface of the porous membrane, and curing it; peeling the porous membrane from the PDMS, flipping it over and laying it on a metal substrate; cleaning it by plasma etching to form a micron column structure; covering the surface of the micron column structure with a metal layer, and assembling it with a friction layer by cutting to form a MC-TENG sensor. The embodiment of the present application prepares the MC-TENG sensor by synergistically combining a porous membrane template and plasma etching; it is beneficial to reduce the preparation cost and promote the wide application of TENG sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] 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.

[0033] Figure 1 A schematic diagram of a process of an embodiment of a method for preparing a MC-TENG sensor provided in an embodiment of the present application;

[0034] Figure 2 A scanning electron microscope schematic diagram of a PET porous membrane provided in an embodiment of the present application;

[0035] Figure 3 A schematic diagram of a scanning electron microscope of a micro-pillar structure substrate provided in an embodiment of the present application;

[0036] Figure 4aA physical diagram of an embodiment of the MC-TENG sensor provided in the embodiments of the present application;

[0037] Figure 4b A wearing diagram of an embodiment of the MC-TENG sensor provided in the embodiment of the present application;

[0038] Figure 4c A schematic diagram of wearing a blood pressure measurement system according to an embodiment of the present application;

[0039] Figure 5 A schematic diagram of the structure of an embodiment of a blood pressure monitoring system provided in an embodiment of the present application;

[0040] Figure 6 A PCB diagram of an embodiment of a blood pressure monitoring system provided in an embodiment of the present application;

[0041] Figure 7 An electrical schematic diagram of an embodiment for MC-TENG sensor signal amplification provided in an embodiment of the present application;

[0042] Figure 8 An electrical schematic diagram of an embodiment of an ECG signal simulation front end provided in an embodiment of the present application;

[0043] Fig. 9 An electrical schematic diagram of an embodiment of a control module provided in an embodiment of the present application;

[0044] Fig.10 An electrical schematic diagram of an embodiment of a Bluetooth module provided in an embodiment of the present application;

[0045] Fig.11 An electrical schematic diagram of an embodiment of a power module provided in an embodiment of the present application;

[0046] Fig.12 An interface display effect diagram of an embodiment of a terminal provided in an embodiment of the present application;

[0047] Fig.13 This is an interface display effect diagram of another embodiment of the terminal provided in the embodiment of the present application;

[0048] Fig.14a A schematic diagram of an embodiment of PTT calculation provided in an embodiment of the present application;

[0049] Fig.14b A bar chart of an embodiment of reference data for PTT blood pressure calculation provided in an embodiment of the present application;

[0050] Fig.14c A comparison chart of the measurement results of two blood pressure measurements provided in an embodiment of the present application;

[0051] Fig.14d A comparison chart of the difference between the two blood pressure measurement results provided in the embodiment of the present application;

[0052] Fig.14e This is a display effect diagram of an embodiment of continuous blood pressure measurement provided in an embodiment of the present application. DETAILED DESCRIPTION

[0053] 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.

[0054] Hypertension is one of the most important risk factors for cardiovascular disease because it often does not show obvious early symptoms before causing significant damage to the heart, kidneys, arteries and brain. Early detection of hypertension is crucial because timely intervention measures (including lifestyle changes and drug treatment) can effectively control blood pressure, thereby reducing the risk of serious cardiovascular complications, reducing mortality and morbidity of related diseases, and ultimately protecting public health worldwide. Therefore, early diagnosis and monitoring of hypertension and related cardiovascular diseases are crucial. Heartbeat and blood pressure are key indicators for assessing human health. As an intuitive reflection of the heartbeat, the pulse wave has been used for physiological monitoring and disease diagnosis for thousands of years, especially in the field of traditional Chinese medicine. At the same time, blood pressure, as a key parameter for assessing heart and blood vessel function, can reveal the health of the circulatory system. By continuously monitoring heartbeat and blood pressure, early diagnosis and intervention can be provided for cardiovascular disease, thereby significantly reducing the risk of cardiovascular events and their mortality. Many patients with hypertension may not have obvious symptoms, and blood pressure testing is the only reliable detection method.

[0055] However, current methods of blood pressure monitoring have limitations. Although devices such as electrocardiographs, cardiac ultrasound, and intravenous cannulation are accurate, they are bulky and require professional operation, making them unsuitable for home use. Although cuff-type sphygmomanometers have been proven to be accurate and practical, they rely on compression of blood vessels for measurement, which may cause discomfort to patients, so noninvasive and convenient monitoring solutions are needed. In clinical practice, blood pressure is a basic vital sign that can comprehensively reflect the patient's cardiac output, vascular elasticity, and overall blood circulation, which is crucial for diagnosing cardiovascular disease. However, traditional cuff sphygmomanometers measure blood pressure by applying pressure to the arm, which may disrupt blood supply to the hand and cause patient discomfort. In addition, this method does not support continuous monitoring, hindering effective long-term patient management. Ongoing studies have confirmed a significant correlation between pulse wave transit time and blood pressure. Theoretical models of this relationship combine factors such as vascular elasticity, blood density, and subcutaneous tissue properties, which can be quantified using empirical formulas, algorithms, and machine learning models, providing a feasible method for noninvasive, continuous, and cuff-free blood pressure monitoring.

[0056] In summary, the development and application of advanced non-invasive monitoring technologies can better protect public health and reduce the morbidity and mortality of cardiovascular diseases.

[0057] In the field of blood pressure (BP) monitoring, conventional techniques often face significant limitations, prompting a shift towards innovative cuffless approaches. The correlation between pulse wave velocity and BP proposed by researchers is a potential solution for noninvasive, cuffless BP monitoring. These methods use electrocardiogram (ECG) signals as a reference to measure pulse wave transit time (PTT) and pulse arrival time (PAT), or rely on the time difference between multiple photoplethysmography (PPG) signals to assess BP. However, the use of PPG sensors to detect pulse waves in the peripheral area of ​​the body poses certain challenges, such as susceptibility to external light interference, skin color changes, and other environmental factors, which may affect the accuracy of BP. Emerging flexible pressure-sensitive sensors offer many advantages, including enhanced user comfort, intuitive interfaces, high sensitivity to pressure changes, and self-healing properties, thus opening up new avenues for sensor technology. Among them, triboelectric nanogenerator (TENG) sensors are able to directly generate electrical signals under external loads, enabling efficient detection and recording. This makes them very suitable for integration into portable electronic systems, especially in self-powered and low-power applications. TENG excels in converting mechanical energy into electrical signals and offers a variety of material options, design flexibility, excellent biocompatibility, and material degradability. Flexible TENG sensors utilize a bendable interface to seamlessly integrate with the human body, accurately detect key health indicators such as movement, heartbeat, respiration, pulse, and blood pressure, and can also provide power for implantable devices in the body, gradually being used in self-powered wearable physiological signal monitoring devices. For example, TENG-based sensors have been applied to human-computer interaction, respiratory monitoring, physical rehabilitation, and motion recognition, which may completely change the traditional medical device paradigm and are considered to be a potential advanced technology to replace traditional medical devices.

[0058] To optimize the performance of TENG, researchers have conducted in-depth studies on its structure and working principle. The working principle of TENG involves two processes: triboelectric effect and electrostatic induction. The triboelectric effect is responsible for the generation of initial charge during the contact and separation of materials, and the amount of charge generated depends on the material properties, contact area and surface morphology. Electrostatic induction determines the transfer of charge; when the materials separate, the generated electric field induces a current in the external circuit, which is affected by factors such as external load, motion mode and degree of separation. The performance of TENG mainly depends on the charge density on its friction contact surface. As confirmed by numerous studies, increasing this surface charge density can improve the electrical power output of TENG. The results show that selecting friction materials with high charge density and optimizing the surface structure of the friction layer are key strategies to improve the charge output capacity of TENG. In order to maximize the surface contact area and improve the performance, microstructures with specific morphologies are usually incorporated into the friction layer, such as kirigami, hemispherical arrays, curved structures, pyramids, micropillars and microgrids. Although photolithography remains the mainstream method for manufacturing these complex microstructures, providing high accuracy and precision in morphology, its complexity and time-intensiveness pose challenges, especially in terms of scalability and economic feasibility in large-scale production scenarios. Innovative fabrication techniques that can balance precision, efficiency, and cost-effectiveness are needed, which will expand the potential of TENGs in a wide range of applications.

[0059] By changing the material, increasing the contact area and other methods, the sensitivity of TENG can be effectively improved to detect weak physiological signals such as pulse. In this regard, the present invention adopts a low-cost and mass-producible technology to realize the preparation of micron column structure. Using the etching process film as the substrate, combined with the spin coating method and plasma etching technology, a scheme for manufacturing CNT / PDMS flexible micron column structure with adjustable micro column density, adjustable diameter, adjustable height and adjustable charge density is designed. After sputtering a 100nm gold layer on this structure, it is used as a friction layer, and a micron column triboelectric nanogenerator (MC-TENG) sensor is developed in combination with FEP film. The sensor is designed to monitor the human fingertip pulse and non-invasive pressure-free blood pressure. The micron column array of CNT / PDMS composite material effectively increases the contact area of ​​triboelectricity and significantly improves the charge density of the material. Compared with the sensor of the same structure, the output performance is improved by 10 times. Thanks to the excellent characteristics of the micron column structure, the MC-TENG sensor can accurately detect weak vibrations and tiny mass changes, showing its great potential in monitoring cardiovascular systems such as pulse. Under a pressure of 6kPa, the sensor showed excellent sensitivity and was still able to accurately measure pulse waves after 12 months, with almost no attenuation in output performance after 30,000 cycles of compression.

[0060] The accuracy of MC-TENG sensors in cardiovascular health monitoring has been verified through experimental and simulation tests. It can provide stable and informative pulse wave signals, and its linear fit with the electrocardiogram (ECG) heart rate interval reaches 99.54%. Further combining the MC-TENG sensor with ECG, we developed a device for fingertip pulse monitoring and real-time, non-invasive, and beat-to-beat blood pressure measurement without additional pressure, verifying the feasibility of MC-TENG in wearable pulse real-time monitoring. The pulse wave signal captured by the sensor has an SNR of 43.6dB and an RMSE of 0.289%, with 99.54% synchronization with the ECG heart rate cycle, confirming the feasibility of the sensor for continuous pulse monitoring management. This system can continuously obtain the pulse conduction time of each heartbeat in combination with the ECG signal, and the system is externally calibrated by measuring the initial blood pressure with a commercial sphygmomanometer, realizing long-term beat-to-beat blood pressure monitoring. This system continuously detects the blood pressure of a specific individual after a blood pressure calibration. The average standard deviation of systolic and diastolic blood pressure compared with the blood pressure measured by the cuff sphygmomanometer in the 10-day blood pressure measurement was -0.40±3.80mmHg and 0.36±3.97mmHg, respectively. At the same time, we measured the changes in the blood pressure of the subjects when standing and squatting, from 121mmHg when standing to 157mmHg after squatting, and returned to the initial state after standing, proving the ability of the system to dynamically monitor blood pressure. The upper computer interface can display the pulse wave curve, ECG signal curve, and beat-to-beat blood pressure curve in real time.

[0061] In summary, this application makes individual health monitoring simpler and more effective, helping users better understand their own health status and improve personalized medical care. It provides a simple and effective method for personal cardiovascular health self-assessment in a home environment, which can be operated without professional technology. More importantly, it supports long-term continuous data collection and analysis, which helps to identify signs and risk factors of cardiovascular disease at an early stage, thereby reducing the risk of morbidity and mortality. In short, this study provides a convenient and personalized method for cardiovascular health assessment and monitoring for people who cannot directly access medical facilities, and is expected to have a positive impact on improving public health. Our blood pressure monitoring system provides more possibilities for early detection, diagnosis and telemedicine of cardiovascular disease.

[0062] The following describes in detail a method for preparing a MC-TENG sensor and a blood pressure monitoring system according to an embodiment of the present invention with reference to the accompanying drawings. First, a method for preparing a MC-TENG sensor according to an embodiment of the present invention is described with reference to the accompanying drawings.

[0063] Figure 1 Schematic diagram of the preparation method of a MC-TENG sensor according to an embodiment of the present invention, comprising:

[0064] Providing a substrate, and spreading PDMS on the substrate;

[0065] Laying a porous membrane on the PDMS and performing a curing treatment to form a cavity;

[0066] Applying a composite material on the cavity and performing a spin coating process so that the composite material fills the cavity; the composite material includes CNT and PDMS;

[0067] Scrape off the composite material on the surface of the porous membrane and perform a curing treatment;

[0068] The porous membrane is peeled off from the PDMS, turned over and laid flat on a metal substrate; and cleaned by plasma etching to form a micron column structure;

[0069] A metal layer is covered on the surface of the micron column structure, and is assembled with the friction layer through cutting to form a MC-TENG sensor.

[0070] In some embodiments, the present application embodiment can lay a mixture of polydimethylsiloxane (PDMS, Sylgard 184, DowCorning) on ​​the substrate, and the mixture is: the weight ratio of the crosslinker to PDMS is 1:10. The porous membrane in the present application can be a PET porous membrane or a PC porous membrane. The specific preparation process can be:

[0071] S11. Spread a layer of PDMS (the weight ratio of cross-linking agent to PDMS is 1:10) on a flat surface, such as the bottom of a round or square plastic culture dish, in order to form a sealing layer.

[0072] S12. Lay a porous membrane on the uncured PDMS and quickly put it into an oven at 80°C for curing for 2 hours, in order to seal the bottom of the porous membrane and leave the hole on the top. Figure 2 Scanning electron microscope (SEM) image of the PET porous membrane is shown.

[0073] S13. Apply a CNT / PDMS mixture (the weight ratio of CNT to PDMS ranges from 0 to 1 / 8) on top of the hole, and then use spin coating (using centrifugal force) to infiltrate the mixture into the hole to complete the filling; the spin coating speed is 500r / min~2000r / min, and the duration is 60s-300s. The smaller the pore size, the higher the spin coating speed and the longer the time required.

[0074] S14, the residual CNT / PDMS mixture on the surface is hung off, the purpose is to keep the porous membrane clean and still in a translucent state. At this time, the porous membrane with the CNT / PDMS mixture is placed in an oven for curing, and after curing at 40 degrees Celsius for 24 hours, it is taken out and the appearance is unchanged from before being placed.

[0075] S15. Peel off the porous membrane from the PDMS layer on the bottom. Turn it over, lay it flat on the aluminum foil, fix it with tape on all sides, and put it into the plasma etcher for surface cleaning. Use an oxygen flow rate of 100mL / min, RF power of 100W, and an etching time of 90min. Figure 3 As shown, the SEM image of the CNT / PDMS microcolumn structure formed on the PET substrate.

[0076] S16. Sputter a layer of gold with a thickness of 50 nm on the surface of the micrometer column structure, parameters are Ar, gas flow rate is 200 sccm, RF power is 300 W, and the duration is 60 s.

[0077] S17, cutting, and assembling with FEP friction layer into MC-TENG sensor, size 14mmx14mm. Figure 4a The sensor prepared by the above-mentioned preparation method is shown, Figure 4b As shown in the figure, the MC-TENG is attached to the index finger of the subject for real-time pulse wave monitoring. Figure 4c As shown, the scenario diagram of blood pressure measurement through MC-TENG sensor and ECG signal.

[0078] The micron column structure is used to make a wearable triboelectric nanogenerator sensor to monitor human pulse and measure blood pressure. The embodiment of the present application has a cost-effective manufacturing strategy that combines a porous membrane template with radio frequency (RF) etching. This method can effectively manufacture microcolumn structures while maintaining good morphological control. Using this technology, a microcolumn triboelectric nanogenerator (MC-TENG) sensor for monitoring pulse waves is designed. The sensor has a micron-scale columnar structure and a strain layer, high sensitivity, good signal-to-noise ratio, and strong stability. It can accurately respond to small changes in pressure and can stably detect human pulse waves. Compared with traditional resistive strain sensors using similar microcolumn structures, the sensitivity of MC-TENG sensors is one order of magnitude higher. The good performance of sensitivity greatly simplifies the design of signal acquisition and amplification circuits. The pulse wave signal of MC-TENG can be further derived into blood pressure by calculation, and these applications have potential benefits for individuals seeking to independently monitor cardiovascular health, especially in home environments or other personal environments. This may provide opportunities for the elderly and those with limited mobility, as traditional monitoring methods may pose challenges to them. The embodiments of this application will promote the further development of personalized medical evaluation and treatment and contribute to the field of medical care technology. This will not only improve the accessibility and effectiveness of health monitoring, but also conform to the growing trend of patient-centered medical care, allowing individuals to play a more active role in managing their own health.

[0079] Optionally, in the preparation method of the MC-TENG sensor in the embodiment of the present invention, the porous membrane includes a PET porous membrane, and the parameters of the PET porous membrane that need to be determined include: the pore size of the PET porous membrane is 450nm to 20um; the density of the PET porous membrane is 4x10 4 Up to 1x10 8 Pieces / cm 2 .

[0080] Optionally, in the method for preparing the MC-TENG sensor in the embodiment of the present invention, the parameters that need to be determined for the plasma etching include: an oxygen gas flow rate of 90 to 110 mL / min; an RF radio frequency power of 90 to 110 W; and the method further includes:

[0081] The longer the etching time, the higher the height of the formed micron pillars;

[0082] The required etching time is inversely proportional to the power of the RF radio frequency; the required etching time is inversely proportional to the oxygen gas flow rate.

[0083] In some possible implementations, based on a PET porous membrane, an oxygen flow rate of 100 mL / min, an RF power of 100 W, an etching time of 30 min, a CNT / PDMS micron column height of about 0.5-1 um, a height of 1-2 um at 60 min, and a height of 2-5 um at 120 min. It can be seen that a high RF power results in a short etching time, and a low RF power results in a long etching time. Similarly, the smaller the oxygen flow rate, the longer the etching time, and vice versa.

[0084] Optionally, the method for preparing the MC-TENG sensor in the embodiment of the present invention, wherein the assembling with the friction layer to form the MC-TENG sensor comprises:

[0085] On the substrate of the micron column structure, electrode wires are connected by heating and pressurizing to form a positive friction layer;

[0086] Another porous membrane is taken, and a metal layer is covered on the surface of the porous membrane to make a negative triboelectric layer electrode;

[0087] A negative friction layer material FEP is inserted between the positive friction layer and the negative friction electric layer electrode to encapsulate into a MC-TENG sensor.

[0088] Optionally, in the preparation method of the MC-TENG sensor in an embodiment of the present invention, the weight ratio of CNT to PDMS in the composite material is 0 to 1 / 8, and the output performance of the MC-TENG sensor increases with the increase of the CNT specific gravity; the parameters of the spin coating process include: the spin coating speed is 500r / min to 2000r / min, and the spin coating time is 60s to 300s.

[0089] The preparation method provided in the embodiment of the present application includes: providing a substrate, and laying PDMS on the substrate; laying a porous membrane on the PDMS, and curing it to form a cavity; applying a composite material on the cavity, and spin coating it so that the composite material fills the cavity; the composite material includes CNT and PDMS; scraping off the composite material on the surface of the porous membrane, and curing it; peeling the porous membrane from the PDMS, flipping it over and laying it on a metal substrate; cleaning it by plasma etching to form a micron column structure; covering the surface of the micron column structure with a metal layer, and assembling it with a friction layer by cutting to form a MC-TENG sensor. The embodiment of the present application prepares the MC-TENG sensor by synergistically combining a porous membrane template and plasma etching; it is beneficial to reduce the preparation cost and promote the wide application of TENG sensors.

[0090] Next, a blood pressure monitoring system according to an embodiment of the present invention will be described with reference to the accompanying drawings, including:

[0091] The MC-TENG sensor prepared by the above-mentioned method for preparing the MC-TENG sensor is used to obtain the pulse wave signal of the monitored object;

[0092] An analog front-end module, used for acquiring an ECG signal of the monitored object;

[0093] The control module is used to collect the pulse wave signal and the ECG signal, and determine the blood pressure of the monitored object based on the pulse wave signal and the ECG signal.

[0094] Reference Figure 5 As shown, in some embodiments, the present application embodiment includes a transimpedance amplification circuit (1) of a MC-TENG sensor signal, an analog front-end circuit (2) of an ECG signal, a microcontroller circuit (3), a Bluetooth module circuit (4), a serial communication circuit (5), and a power supply-battery circuit (6). Figure 6 The PCB design diagram is shown. The MC-TENG pulse signal and ECG signal are amplified and filtered by the TIA circuit and the analog front-end module, and then enter the ADC inside the MCU module to convert them into digital signals and then filter them. Then, the data is transmitted to the PC or mobile device through serial communication or Bluetooth module for PTT calculation and blood pressure derivation.

[0095] Optionally, in the blood pressure monitoring system in the embodiment of the present invention, the control module is further used for:

[0096] According to the reference blood pressure value measured by the cuff sphygmomanometer, a corresponding relationship with the reference pulse wave transmission time is established to complete the calibration of the blood pressure measurement of the same test subject by the blood pressure monitoring system;

[0097] The pulse transmission time of the blood pressure to be measured is determined based on the pulse wave signal and the ECG signal over a period of time, and the blood pressure of the monitored object is determined based on the reference blood pressure value and the reference pulse wave transmission time.

[0098] Optionally, the blood pressure monitoring system in the embodiment of the present invention further comprises:

[0099] an amplifier circuit, used to amplify the pulse wave signal measured by the MC-TENG sensor;

[0100] The amplification circuit includes an operational amplifier, the MC-TENG sensor is connected to the inverting input terminal of the operational amplifier, and the inverting input terminal of the operational amplifier is connected to the output terminal of the operational amplifier through a resistor and a capacitor; the first power supply is connected to the non-inverting input terminal of the operational amplifier through a first resistor, and the non-inverting input terminal of the operational amplifier is grounded through a second resistor.

[0101] In some possible implementations, reference Figure 7 As shown in the figure, this circuit uses the OPA2377 operational amplifier to amplify the tiny current signal generated by the MC-TENG sensor. Among them, the resistor RFA1 (1GΩ) and the capacitor CFA1 (3pF) together constitute a transimpedance amplifier circuit and a low-pass filter. In addition, the voltage divider circuit composed of the first resistor RA0 (100kΩ) and the second resistor RA1 (50kΩ) provides a voltage bias of about 1.67V for the in-phase input of the operational amplifier OPA2377, ensuring that the signal of the MC-TENG sensor is increased to the bias voltage after amplification, thereby preventing the bottom or top of the pulse wave signal from being flattened, making it easier for the subsequent microcontroller to use the built-in ADC to collect the signal.

[0102] Optionally, the blood pressure monitoring system in the embodiment of the present invention further comprises:

[0103] A terminal, used for displaying the pulse wave signal, the ECG signal, the blood pressure value and the change curve;

[0104] The Bluetooth module is used for data transmission between the control module and the terminal.

[0105] In some embodiments, reference Figure 8As shown, the analog front-end circuit (i.e., analog front-end module) of the ECG signal in this application adopts the AD8232 single-lead ECG front-end signal conditioning chip, and realizes the amplification and filtering of the ECG signal by configuring the surrounding resistance and capacitance parameters. The amplification factor is 1100 times, and the frequency range is limited to between 0.3 and 37 Hz.

[0106] Reference Fig. 9 The microcontroller circuit (i.e., control module) shown uses the STM32F103C8T6 microprocessor produced by ST Company, and uses its built-in 12-bit ADC to digitize the pulse signal and ECG signal at a speed of 1kbps, and transmits the collected data to the host computer on the computer side or the mobile phone APP.

[0107] Reference Fig.10 As shown, the left side is the Bluetooth module circuit: the RF-BM-4044B4 module is used to realize serial communication with the mobile phone Bluetooth, so as to transmit the pulse signal and ECG signal data to the mobile phone APP, thereby realizing the PTT calculation and blood pressure monitoring functions. The right side is the serial communication circuit: the CH340E USB conversion chip of Nanjing Qinheng Company is used to support communication with the PC and achieve a baud rate of up to 2w bps. Fig.11 The power supply and battery circuit shown: The circuit is connected to the computer through the Type-C interface to achieve data transmission and power supply. At the same time, it provides battery support for Bluetooth communication, and the lithium battery charging management is completed through the LTH7R chip.

[0108] It can be seen that the contents of the above method embodiments are all applicable to the present system embodiments, the functions specifically implemented by the present 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.

[0109] The following is a detailed introduction to the preparation method of the MC-TENG sensor and the blood pressure monitoring system provided in the embodiment of the present application by using a specific embodiment:

[0110] Reference Figure 1The preparation process presented in two-dimensional and three-dimensional forms is shown in Figure 1. The preparation method of the MC-TENG sensor includes: coating a mixture of polydimethylsiloxane (PDMS, Sylgard 184, DowCorning) and a curing agent in a mass ratio of 10:1 on a flat glass or plastic substrate. Subsequently, a PET porous membrane is covered on the PDMS surface and immediately cured at 80°C for 2 hours to block the holes formed on the surface at the bottom of the porous membrane, and then cooled. PDMS and carbon nanotubes (CNTs) are fully mixed in an organic solvent, and then the CNT / PDMS composite material is spin-coated into the porous structure of PET at a speed of 1000 rpm for 60 seconds. The excess CNT / PDMS composite material on the surface of the porous PET membrane is scraped off, and the sample is thermally cured at 40°C for 24 hours. After this step, the PET porous membrane filled with CNT / PDMS micropillars is peeled off from the PDMS substrate. The sample was then flipped over and pasted onto a metal substrate. The PET porous membrane was treated with oxygen plasma etching technology to thin the PET porous membrane, so that the CNT / PDMS composite material that could not be etched was fully exposed, forming a PET membrane substrate with randomly arranged CNT / PDMS microcolumns on the surface. A layer of Au was sputtered on the microstructure surface using magnetron sputtering technology. The PET membrane with a CNT / PDMS microcolumn substrate was cut into a shape of 1.4 cm × 1.4 cm, and the electrode wire was connected to the edge of the substrate by heating and pressing to form the positive triboelectric layer electrode of the MC-TENG sensor. Similarly, gold was sprayed on the surface of a PET membrane of the same size to make an electrode. Subsequently, a FEP film with a thickness of 20 μm and a size of 1.6 cm × 1.6 cm was inserted between the positive and negative electrodes as a negative triboelectric layer, and the sensor was encapsulated with PDMS to make a sandwich structure MC-TENG sensor.

[0111] The human pulse blood pressure monitoring device includes a MC-TENG sensor for collecting pulse wave signals, an electrode patch for collecting ECG signals, and a wearable device circuit board. The circuit board and structural diagram are shown in Figure 6 , see the schematic diagram Figure 5 The key to the signal conditioning circuit is the transimpedance amplifier circuit consisting of an ultra-low bias current OPA2377, a 1GΩ resistor, and a 5pF capacitor, with an amplification factor of 10 9, where RC constitutes a hardware passive low-pass filter to suppress the high-frequency noise of the sensor, and the cut-off frequency is about 31Hz. The circuit converts the pulse wave current signal collected by MC-TENG into a voltage signal, which is converted into a digital signal through the ADC module integrated in the STM32F103 microcontroller with a sampling rate of 1kHz, triggered by an internal timer, and transmitted to the computer. The ECG signal conditioning and amplification circuit consists of an integrated signal conditioning chip AD8232 and its peripheral components. In order to obtain the ECG waveform with the least distortion, the AD8232 is configured according to the heart monitor, with a total system gain of 1100, a 0.5Hz bipolar high-pass filter, and a bipolar 40Hz low-pass filter. The amplified ECG analog signal is also converted into a digital signal by the integrated ADC module of the STM32F103 microcontroller with a sampling rate of 1kHz.

[0112] The present application embodiment also provides a host computer software including a mobile phone APP and a computer software. Fig.12 As shown in the figure, the mobile phone APP interface includes the waveform display area of ​​ECG signal and pulse wave, and the numerical display area of ​​PTT, heart rate and blood pressure. Clicking the APP waveform display area will send a start acquisition instruction to the wearable device that collects the signal. After receiving the command, the hardware circuit samples the pulse and ECG signals at a rate of 1kHz and sends them to the mobile phone APP. The mobile phone processes the data every 1 second, displays the latest 5 seconds of waveform, and updates the current heart rate (ECG HR), PTT and blood pressure assessment values.

[0113] The computer software interface is as follows Fig.13 As shown in the figure, the upper part shows the operation buttons and key values, and the lower part shows two drawing areas, which respectively display the real-time pulse and ECG signal curves and the continuous blood pressure curve. The user only needs to input the blood pressure value measured by the cuff sphygmomanometer. After the system obtains a stable pulse signal, click the "Calculate PTT0" button to enter the PTT value into the PTT0 field as a reference for subsequent blood pressure evaluation. After connecting the MC-TENG sensor and ECG electrode, connect the hardware circuit to the computer via a USB cable, select and open the corresponding COM port in the software interface, and send the start acquisition command. After receiving the command, the hardware circuit samples the pulse and ECG signals at a rate of 1kHz and uploads them to the computer. The computer processes the data every 1 second and updates the current heart rate (HR), PTT and blood pressure evaluation values. The software only displays the data of the last 5 seconds, estimates the latest SBP and DBP values ​​according to the PTT-BP formula, and updates and displays these data together with the pulse and ECG curves (upward). The boxed part in the figure shows the blood pressure fluctuations caused by three deep breaths.

[0114] Example:

[0115] In this application, the pulse transmission time PTT refers to the time difference from the beginning of heart contraction (ECG signal) to the arrival of the pulse wave at the tip of the index finger (MC-TENG pulse wave signal), without considering the propagation time of the ECG signal from the heart to the wrist. Fig.14a As shown in the figure, the calculation of PTT starts from the R peak of ECG and ends at the P peak of the pulse wave in the same cycle. This method of combining MC-TENG pulse wave signal with ECG electrocardiogram signal does not need to consider the test position of the ECG electrode, but only depends on the test position of MC-TENG. Compared with the traditional method of using the P and D time difference ΔT of the radial artery pressure wave DVP Compared with the method of calculating pulse wave velocity (PWV) by MC-TENG, the measurement method based on the time difference between MC-TENG pulse wave signal and ECG electrocardiogram signal is not affected by the detailed characteristic peak of the pulse wave signal, has low requirements on the quality of the pulse wave signal, and is suitable for subjects of different ages. We recruited a 40-year-old healthy male volunteer to verify the application of the MC-TENG non-invasive dynamic blood pressure monitoring system. To ensure the accuracy and reliability of the experimental data, the volunteer avoided any activities that may cause nervous system stimulation and blood pressure fluctuations within 2 hours before the experiment, including drinking and strenuous exercise. We attached the MC-TENG and ECG electrodes to the fingertip artery and wrist of the volunteer respectively, and then used the MC-TENG non-invasive dynamic blood pressure monitoring system to synchronously collect the pulse wave signal and ECG signal (1kHz, 60 seconds), and obtained the corresponding reference blood pressure of the volunteer through the cuff-type OMRON HEM-7127J sphygmomanometer. The filtfilt function in the MATLAB program is used to filter the MC-TENG pulse wave signal and ECG electrocardiogram signal. After filtering and baseline adjustment of the two signals, a clear ECG signal with a clear R wave peak and a pulse signal with a clear P wave peak are obtained. Among them, the filtering frequency range of the pulse wave is 0.3-30Hz, and the filtering frequency range of the ECG signal is 0.3-35Hz. The filtered pulse and ECG signals are processed with the findpeaks function to obtain the coordinates of adjacent peaks for calculating PTT. Finally, it is substituted into the blood pressure formula to obtain the beat-to-beat blood pressure.

[0116] In order to construct the PPT-BP conversion relationship in the MC-TENG non-invasive dynamic blood pressure monitoring system, we selected a set of PTT-BP data of volunteers as the basic calibration conversion parameters. Fig.14bAs shown in the figure, the average PTT0 of the calibrated PTT-BP data is 230.86836±13.225ms, and the reference systolic blood pressure (SBP0) and reference diastolic blood pressure (DBP0) are 123.9375±2.63737mmHg and 78.975±2.40283mmHg, respectively. Blood pressure is calculated using formula (1) and formula (2). Substitute the PTT0, SBP0 and DBP0 values ​​into the blood pressure conversion formula (1) and formula (2) as basic calibration conversion parameters to complete the calibration of the PTT-BP conversion formula. We can use the calibrated MC-TENG non-invasive dynamic blood pressure monitoring system to infer systolic and diastolic blood pressure through pulse wave signals and ECG signals:

[0117]

[0118] Where SBP0 and DBP0 are the systolic and diastolic blood pressures measured by the cuff sphygmomanometer; PTT0 is the average PTT over a 60-second period; A is approximately equal to 0.017 mmHg and is a coefficient that depends on the subject; and PTT is the pulse transmission time of the blood pressure to be measured.

[0119] Over a 10-day period, we performed multiple PTT-BP blood pressure measurements on the same volunteer using the MC-TENG non-invasive dynamic blood pressure monitoring system. During the experiment, we used MC-TENG and ECG electrodes to measure the pulse and ECG signals of the volunteers 8 times a day (60 seconds per group, 3 minutes between each measurement), and used a traditional cuff-type sphygmomanometer to measure blood pressure as a reference value. Then, the PPT between each group of pulse wave signals and ECG signal data was calculated, and the blood pressure value was derived by bringing it into the PTT-BP conversion formula. Fig.14c As shown in the figure, the blood pressure measured by the MC-TENG non-invasive dynamic blood pressure monitoring system and the reference blood pressure measured by a commercial sphygmomanometer in 10 days are shown. In each group of data in the figure, the left side shows the average blood pressure measurement value (SBP-Cutf, DBP-Cutf) of the commercial sphygmomanometer, and the right side shows the average blood pressure measurement value (SBP-Eval, DBP-Eval) based on the MC-TENG non-invasive dynamic blood pressure monitoring system. From the experimental results, it can be seen that the blood pressure value measured by the MC-TENG non-invasive dynamic blood pressure monitoring system is very close to the blood pressure value measured by the commercial sphygmomanometer, which means that the MC-TENG non-invasive dynamic blood pressure monitoring system has good accuracy. Fig.14dThe standard deviation statistics of the blood pressure measured by the MC-TENG sensor non-invasive dynamic blood pressure monitoring system and the commercial sphygmomanometer over a period of 10 days are given. In the 10-day blood pressure test results, the standard deviations of SBP and DBP measured by the traditional cuff sphygmomanometer were 2.320±0.656mmHg and 1.031±0.476mmHg, respectively, while the fluctuations of SBP and DBP measured by the MC-TENG non-invasive dynamic blood pressure monitoring system were relatively small, with standard deviations of 1.563±0.466mmHg and 0.269±0.141mmHg, respectively.

[0120] Furthermore, we also evaluated the dynamic blood pressure monitoring of the MC-TENG non-invasive dynamic blood pressure monitoring system. In the experiment, we asked volunteers to wear the MC-TENG non-invasive dynamic blood pressure monitoring system, and then continuously perform three states: standing (Ⅰ) (60s), squatting (90s) and standing (Ⅱ) (300s), and monitor the dynamic fluctuation of blood pressure in real time. Fig.14e As shown in the figure, the MC-TENG noninvasive dynamic blood pressure monitoring system completely records the dynamic fluctuation trends of SBP, DBP and PTT. At the beginning of the squatting and standing state (Ⅱ), the volunteers' SBP, DBP and PTT fluctuated significantly. When the volunteers changed from the standing state (Ⅰ) to the squatting state (60s), SBP fluctuated to a certain extent and gradually increased (121mmHg-157mmHg), while DBP had only a slight upward trend. When the volunteers changed from the squatting state to the standing state II (150s), SBP and DBP decreased and gradually returned to the level of the standing state (Ⅰ).

[0121] Therefore, the MC-TENG noninvasive dynamic blood pressure monitoring system can effectively monitor blood pressure dynamically, providing a feasible solution for continuous noninvasive and cuffless blood pressure monitoring management.

[0122] It can be seen that the preparation method provided in the embodiment of the present application has low cost: no complex and expensive manufacturing processes such as photolithography and reverse molding are required, and only oxygen etching is required to realize the batch manufacturing of flexible micron-scale microstructures. The morphology of the microcolumn structure is controllable: the density is adjustable (changing the pore density of the porous membrane), the diameter is adjustable (changing the pore size of the porous membrane), the height is adjustable (changing the time of oxygen etching), the charge density and Young's modulus are adjustable (changing the weight ratio of CNT to PDMS). Non-invasive and cuff-free continuous blood pressure monitoring: Through a homemade wearable device, the ECG signal is used in conjunction with the MC-TENG sensor to obtain PTT, realizing the continuous blood pressure monitoring function.

[0123] An embodiment of the present invention further provides a MC-TENG sensor, which is prepared by the preparation method of the MC-TENG sensor as described above and is used in the blood pressure monitoring system as described above.

[0124] Similarly, the contents of the above method embodiments are all applicable to the present sensor embodiment. The functions specifically implemented by the present sensor embodiment 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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. A method for preparing a MC-TENG sensor, characterized in that: The method comprises: Providing a substrate, and spreading PDMS on the substrate; Laying a porous membrane on the PDMS and performing a curing treatment to form a cavity; Applying a composite material on the cavity and performing a spin coating process so that the composite material fills the cavity; the composite material includes CNT and PDMS; Scrape off the composite material on the surface of the porous membrane and perform a curing treatment; The porous membrane is peeled off from the PDMS, turned over and laid flat on a metal substrate; and cleaned by plasma etching to form a micron column structure; A metal layer is covered on the surface of the micron column structure, and is assembled with the friction layer through cutting to form a MC-TENG sensor.

2. The method for preparing the MC-TENG sensor according to claim 1, characterized in that: The porous membrane includes a PET porous membrane, and the parameters of the PET porous membrane that need to be determined include: the pore size of the PET porous membrane is 450nm to 20um; the density of the PET porous membrane is 4x10 4 Up to 1x10 8 Pieces / cm 2 .

3. The method for preparing the MC-TENG sensor according to claim 2, characterized in that: The parameters that need to be determined for the plasma etching include: an oxygen gas flow rate of 90 to 110 mL / min; an RF radio frequency power of 90 to 110 W; and the method further includes: The longer the etching time, the higher the height of the formed micron pillars; The required etching time is inversely proportional to the power of the RF radio frequency; the required etching time is inversely proportional to the oxygen gas flow rate.

4. The method for preparing the MC-TENG sensor according to claim 1, characterized in that: The assembling with the friction layer to form the MC-TENG sensor comprises: connecting electrode wires on the substrate of the micron column structure by heating and pressurizing to form a positive friction layer; Another porous membrane is taken, and a metal layer is covered on the surface of the porous membrane to make a negative triboelectric layer electrode; A negative friction layer material FEP is inserted between the positive friction layer and the negative friction electric layer electrode to encapsulate into a MC-TENG sensor.

5. The method for preparing the MC-TENG sensor according to claim 1, characterized in that: The weight ratio of CNT to PDMS in the composite material is 0 to 1 / 8, and the output performance of the MC-TENG sensor is enhanced as the specific gravity of CNT increases; The parameters of the spin coating process include: a spin coating speed of 500 r / min to 2000 r / min, and a spin coating time of 60 s to 300 s.

6. A blood pressure monitoring system, characterized in that: The monitoring system comprises: The MC-TENG sensor prepared by the preparation method of the MC-TENG sensor according to any one of claims 1 to 5 is used to obtain a pulse wave signal of a monitored object; An analog front-end module, used for acquiring an ECG signal of the monitored object; The control module is used to collect the pulse wave signal and the ECG signal, and determine the blood pressure of the monitored object based on the pulse wave signal and the ECG signal.

7. The blood pressure monitoring system according to claim 6, characterized in that: The control module is also used for: According to the reference blood pressure value measured by the cuff sphygmomanometer, a corresponding relationship with the reference pulse wave transmission time is established to complete the calibration of the blood pressure measurement of the same test subject by the blood pressure monitoring system; The pulse transmission time of the blood pressure to be measured is determined based on the pulse wave signal and the ECG signal over a period of time, and the blood pressure of the monitored object is determined based on the reference blood pressure value and the reference pulse wave transmission time.

8. The blood pressure monitoring system according to claim 6, characterized in that: The monitoring system further comprises: an amplifier circuit, used to amplify the pulse wave signal measured by the MC-TENG sensor; The amplification circuit includes an operational amplifier, the MC-TENG sensor is connected to the inverting input terminal of the operational amplifier, and the inverting input terminal of the operational amplifier is connected to the output terminal of the operational amplifier through a resistor and a capacitor; the first power supply is connected to the non-inverting input terminal of the operational amplifier through a first resistor, and the non-inverting input terminal of the operational amplifier is grounded through a second resistor.

9. The blood pressure monitoring system according to claim 6, characterized in that: The monitoring system further comprises: A terminal, used for displaying the pulse wave signal, the ECG signal, the blood pressure value and the change curve; The Bluetooth module is used for data transmission between the control module and the terminal.

10. A MC-TENG sensor, characterized in that: The MC-TENG sensor is prepared by the preparation method of any one of claims 1 to 5 and is used in the blood pressure monitoring system as described in any one of claims 6 to 9.

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