Temperature, pressure and humidity multi-mode sensing system based on ionic gel

Abstract

The invention belongs to the technical field of medical sensors, and particularly relates to a temperature, pressure and humidity multi-mode sensing system based on ionic gel. According to the sensing system, measurement sensing of temperature, pressure and humidity can be realized; the device specifically comprises a sensing module and an arterial duct or a medical sponge for bearing the sensing module, the sensing module comprises ionic gel prepared by mixing ionic liquid and polyvinylidene fluoride-hexafluoropropylene, copper foil electrodes fixed on two sides of the ionic gel, and an enameled copper wire used for connecting the electrodes and a universal meter; the sensing module is embedded into the tail end of the catheter or the medical sponge to obtain sensing devices in two different application scenes, namely monitoring of a cardiovascular system and monitoring of a wound vacuum drainage state; a wire led out from the sensing module is connected with a universal meter, so that the real-time monitoring of various biological signs is realized; the sensor can replace a traditional medical sensor, is higher in sensitivity, and has the advantages of being low in cost, light in weight, good in biocompatibility and the like.

Description

[0001] Technology Neighborhood

[0002] The invention belongs to the technical field of medical sensors, and in particular relates to a multimodal sensor. Background Art

[0003] In modern medical technology, sensors are widely used, especially in clinical scenarios, where a large number of sensors are needed to monitor various physiological parameters and synchronize important signs such as blood pressure, core body temperature, wound bleeding, etc. This function is particularly important for timely saving patients' lives in clinical practice, especially in critical situations such as shock. It is critical to be able to monitor and quickly reflect changes in patients' injuries in real time. However, existing sensor technology is mainly based on inorganic semiconductor materials. Although these materials are relatively mature, they have some significant disadvantages in medical applications: high manufacturing cost, bulky (not conducive to wearing and carrying), poor biocompatibility, etc. In medical applications, sensors need to be in direct contact with human tissue, so the biocompatibility of materials is a key consideration. Inorganic semiconductor materials may trigger immune or allergic reactions, increasing patient discomfort and potential medical risks.

[0004] In addition, existing commercial sensors usually only have a single function and cannot detect other related parameters at the same time. This means that in practical applications, patients need to wear a variety of different sensors to monitor various physiological parameters at the same time. This not only increases the burden on patients, but also makes data integration and analysis more complicated. Especially in wound care, there is currently a lack of real-time monitoring technology for vacuum drainage systems. Existing vacuum drainage systems are mainly used for drainage and decompression of wounds, but they cannot monitor important parameters such as temperature, drainage pressure, and bleeding volume at the wound in real time. In this case, it is difficult for medical staff to fully understand the real-time situation of the wound and cannot intervene and treat it in a timely manner.

[0005] In recent years, literature has reported related technologies for multimodal sensing. Most of the temperature sensing is based on traditional electronic thermoelectric technology, and some of them use emerging ionic thermoelectrics. The pressure detection mechanism is mostly based on piezoresistive or capacitive sensing (e.g. Feng et al. ACS Appl. Mater. Interfaces 2019, 11, 21049-2105). Although it also achieves simultaneous measurement of temperature and pressure, it requires external power supply and a more complex device structure, which is not conducive to further reducing the size of the sensor. For self-powered, piezoelectric or triboelectric pressure sensors (e.g. Li et al. ACS Appl. Mater. Interfaces 2023, 15, 14768-14776, Qin et al. Adv. Funct. Mater. 2022, 32, 2201846), there is currently no technology that integrates it with temperature and humidity sensing at one time. If multiple parameters need to be monitored, multiple sensor modules with different functions are still required, which also hinders further size reduction. Summary of the invention

[0006] In view of the shortcomings of existing medical sensor devices, the purpose of the present invention is to provide a multimodal sensing system that is self-powered, has a simple device structure, has good biocompatibility, and can be used in a variety of medical scenarios to meet the urgent needs of the medical system.

[0007] The multimodal sensing system provided by the present invention adopts a single ion gel material to realize multimodal sensing, including measurement sensing of temperature, pressure, and humidity (including water content); specifically comprises: a sensing module for detection and an arterial catheter or a medical sponge for carrying the sensing module; wherein the sensing module comprises an ion gel prepared by mixing an ionic liquid and polyvinylidene fluoride-hexafluoropropylene, copper foil electrodes (i.e., a group of copper foil electrodes) fixed on both sides of the ion gel, and an enameled copper wire for connecting the electrodes to a multimeter; according to the size of the above-mentioned sensing module, a hole is opened at the tail end of the catheter or the medical sponge for embedding the sensing module, thereby obtaining two sensing devices for different application scenarios; the wires led out of the sensing module are connected to the multimeter to realize real-time monitoring of multiple biological signs. The sensor device with arterial catheter as carrier is suitable for monitoring the cardiovascular system, and the detectable parameters include heart rate, cardiac function, blood pressure, core temperature changes, etc., hereinafter referred to as sensor device A; the sensor device with medical sponge as carrier is suitable for monitoring the vacuum drainage status of wounds, and the detectable parameters include bleeding volume, drainage pressure, wound temperature, etc., hereinafter referred to as sensor device B.

[0008] The ion gel has intrinsic piezoelectric and ion thermoelectric properties, and its ion thermoelectric output is positively correlated with the ambient humidity or the water content of the contact object. In addition, the ion gel has the characteristic of superposition of ion thermoelectric properties and piezoelectric properties. Therefore, accurate monitoring of temperature, pressure and humidity / water content can be achieved simultaneously in a single gel. The mass ratio of ionic liquid to polyvinylidene fluoride-hexafluoropropylene is judged by "having good ion thermoelectric properties and sufficient gel strength". Specifically, the mass ratio of ionic liquid to polyvinylidene fluoride-hexafluoropropylene is (1-4):1.

[0009] Among them, the ionic liquid is but not limited to 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; specifically, ionic liquids with ionic thermoelectric properties such as 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium dicyanamide, and 1-ethyl-3-methylimidazolium chloride.

[0010] In the present invention, the ionic liquid is preferably 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and the mass ratio of the ionic liquid to polyvinylidene fluoride-hexafluoropropylene is (1-4): 1. The present invention mainly uses two ratios of 2:1 and 4:1, which have good sensing and mechanical properties, and the pressure and temperature coefficients of the two are significantly different, so that the accuracy of practical application is excellent.

[0011] The multimodal sensing system provided by the present invention has at least two sensing channels between its sensing module and the multimeter; specifically, in the ion gel, the ionic liquid and polyvinylidene fluoride-hexafluoropropylene are in two different ratios, and the two ion gels are respectively arranged between two groups of electrode sheets; the sensing modules corresponding to the ion gels of the two different material ratios are recorded as sensing module I and sensing module II, which are connected in series in the channel; and are used to read voltage signals. The voltage generated by pressure and temperature in the ion gel signals composed of different ionic liquid ratios has different proportions, and the voltage signals of the two can be decoupled according to the pressure and temperature coefficients calibrated in advance.

[0012] The sensor device A can be used as an implantable medical sensor, which is inserted into a vein and placed in a ventricle, and can simultaneously detect changes in biological heart rate, cardiac function, blood pressure and core temperature.

[0013] Sensor device B can be used as a sensor for monitoring the wound condition of trauma patients. It is placed at the wound of the patient and matched with the drainage system. It can simultaneously detect the amount of bleeding, drainage pressure and temperature changes of the wound.

[0014] During the test, sensor A is inserted into the heart of the test subject through the vein; sensor B is fixed to the wound of the trauma patient with the vacuum sealing drainage device. The voltage signal is measured by the multimeter connected to the sensor module wire, and the computer integrates the signals of multiple sensor modules for processing and calculation, and the real-time monitoring results of the above-mentioned multiple signs can be obtained, realizing simultaneous and highly sensitive detection.

[0015] The materials and accessories used in the present invention are low-cost, light-weight, and biocompatible, and the system has a simple structure and is easy to further reduce in size. The above features make it more suitable for clinical medical testing than traditional semiconductor sensors, and can effectively reduce the size and weight of the sensor worn on the patient.

[0016] The sensor based on the piezoelectric or ionic thermoelectric principle of the present invention has the characteristic of being self-powered, and the entire device does not need to be driven by an external power supply.

[0017] The multimodal sensor of the present invention can replace a variety of traditional single-function sensors, and has higher sensitivity, lower cost, lighter weight and better biocompatibility. In addition, in view of the problem that the prior art lacks real-time detection of vacuum drainage systems, the present invention can simultaneously monitor wound temperature, drainage pressure and bleeding volume. The multimodal sensing system of the present invention can realize real-time and comprehensive monitoring of multiple biomedical parameters, improving the efficiency and accuracy of medical monitoring.

[0018] The temperature / pressure / humidity multimodal sensing system based on ion gel provided by the present invention includes but is not limited to the above two sensor devices with different structures, which can be used for real-time monitoring of biological signs in different medical scenarios. It solves the problems of high manufacturing cost, heavy weight, poor biocompatibility and single function of sensors in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the sensor module in the present invention.

[0020] Figure 2 The data detection results of the sensor device A in the present invention are compared with those of the traditional semiconductor sensor.

[0021] Figure 3 This is the data detection result of sensor device B in the present invention.

[0022] Numbers in the figure: 1.1-1.4 are electrodes, among which 1.1 and 1.2 are a group of electrode sheets, 1.3 and 1.4 are a group of electrode sheets; 2 is a first ion gel block, 3 is a second ion gel block; 4- enameled wire, each electrode sheet is connected to a wire, and the two groups of electrode sheets have a total of four wires. DETAILED DESCRIPTION

[0023] Aiming at the needs of medical detection, the present invention provides a temperature / pressure / humidity multimodal sensing system based on ion gel to realize real-time monitoring of multiple vital signs, as follows:

[0024] Reference Figure 1 In the ion gel, the ion liquid uses 1-ethyl-3-methylimidazole bis(trifluoromethylsulfonyl)imide, and the mass ratio of the ionic liquid to polyvinylidene fluoride-hexafluoropropylene is 4:1 and 2:1. It is cut into the required size, and the corresponding sensing modules of the two ion gels are recorded as sensing module I and sensing module II; the two ion gels are sandwiched between two groups of electrode sheets, one group of electrode sheets is 1.1 and 1.2, and the other group of electrode sheets is 1.3 and 1.4. The two groups of electrode sheets are connected by copper enameled wires through silver paste to form two sensing channels, that is, the assembly of the sensor module is completed, which can be assembled on different carriers according to different application scenarios, or ion gel modules with different component ratios can be added according to the detection accuracy requirements. The application detection methods include, but are not limited to:

[0025] Sensor device A, the assembly steps are as follows: open a small hole at one end of the arterial catheter that is large enough to accommodate the sensor module, place the above two sensor modules in the small hole, and pass the copper enameled wire through the catheter and out from the other end of the catheter to connect to the multimeter system. Finally, fill the gap between the module and the tube wall in the small hole with food-grade silicone, and wait for several hours for the silicone to completely dry. During the test, insert the catheter through the patient's internal jugular vein, pass through the right atrium, and allow the tip of the catheter with the sensor module to remain in the right ventricle. The voltage signals of the two sensor modules are collected by the multimeter, and the temperature and pressure sensitivity coefficients of the two sensor modules are measured in advance, and calculated by the following formula:

[0026] ΔV I =a I P+b I (P)ΔT#(1)

[0027] ΔV II =a II P+b II (P)ΔT#(2)

[0028] Where, ΔV I and ΔV II , a I and a II , b I (P) and b II(P) Open circuit voltage, pressure sensitivity, and pressure-related temperature sensitivity of sensor module I (i.e., corresponding to ionic liquid: polyvinylidene fluoride-hexafluoropropylene = 4:1 ion gel) and sensor module II (i.e., corresponding to ionic liquid: polyvinylidene fluoride-hexafluoropropylene = 2:1 ion gel). By collecting voltage data from these two sensors, we can derive real-time temperature and pressure changes, corresponding to changes in the core temperature and blood pressure in the ventricle. Figure 2 The test results of actually placing this sensor in the body of a pig (experimental animal) are shown, where the left coordinate axis (solid line) is the temperature and pressure changes measured by sensor device A from top to bottom; the right coordinate axis (dashed line) is the core temperature and heart rate measured by the existing medical monitor from top to bottom. It can be seen that during the process of the experimental subject experiencing traumatic shock, the data trend measured by sensor device A is basically consistent with the data measured by the traditional medical monitor, and its monitoring frequency is higher and can show more details. In the second half of the data, when the experimental subject was close to death, his heart rate had exceeded the lower limit of the medical monitor test, and the medical monitor could no longer effectively monitor it; at this time, sensor device A can still continue to monitor pressure, showing its wider test range.

[0029] Sensor device B, the assembly steps are as follows: open a rectangular opening of a size that can accommodate the sensor module at the edge of the medical sponge in the closed trauma negative pressure drainage set, and place the above sensor module in it, fill the gap between the two sides of the module and the sponge with silicone, and wait for several hours for the silicone to completely dry. When testing, the sensor device B is embedded in the patient's wound with the drainage system, and the voltage signals of the three sensor modules are collected by a multimeter. Among them, the sensor module I (corresponding to the ionic liquid: polyvinylidene fluoride-hexafluoropropylene = 4:1 ion gel) and the sensor module II (corresponding to the ionic liquid: polyvinylidene fluoride-hexafluoropropylene = 2:1 ion gel) are encapsulated on four sides with food-grade silicone and are not in direct contact with the sponge; the sensor module III (corresponding to the ionic liquid: polyvinylidene fluoride-hexafluoropropylene = 4:1 ion gel) is encapsulated on only three sides, one of which is attached to the sponge to test the water content of the sponge. The voltage signal processing method of sensor modules I and II is the same as that of sensor device A. The changes in temperature and pressure are calculated by the above formulas (1) and (2). Then, based on the water content sensitivity of sensor module III measured in advance, the voltage measured by sensor module III is deducted from the voltage generated by the known temperature and pressure to calculate the water content of the sponge. The three parameters correspond to the temperature, drainage pressure and bleeding volume changes of the internal wound, respectively. Figure 3 The results of the test were shown when the sensor was actually placed in a wound on the surface of a pig (experimental animal). Figure 3 As can be seen in A, compared with the data taken manually with an infrared thermometer, the temperature trend measured by sensor B is consistent with it, and has more continuous and intensive monitoring data, which can observe more details; for drainage pressure ( Figure 3 B) and water content ( Figure 3 C) monitoring can also accurately and timely reflect the manual opening and closing of the drainage system and the changes in bleeding volume.

[0030] The present invention is not limited to the above-described embodiments.

Claims

1. A temperature, pressure and humidity multimodal sensing system based on ion gel, characterized in that: A single ion gel material is used to achieve multimodal sensing, including temperature, pressure, and humidity measurement sensing; specifically, it includes: a sensor module for detection and an arterial catheter or medical sponge for carrying the sensor module; wherein the sensor module includes an ion gel prepared by mixing an ionic liquid with polyvinylidene fluoride-hexafluoropropylene, copper foil electrodes fixed on both sides of the ion gel, and enameled copper wires for connecting the electrodes to a multimeter; according to the size of the above-mentioned sensor module, a hole is opened at the tail end of the catheter or the medical sponge for embedding the sensor module, thereby obtaining two sensor devices for different application scenarios; the wires leading out of the sensor module are connected to a multimeter, thereby achieving real-time monitoring of multiple biological signs; wherein: The sensor device using the arterial catheter as a carrier is suitable for monitoring the cardiovascular system. The detectable parameters include heart rate, cardiac function, blood pressure, and core temperature changes, referred to as sensor device A; The sensor device using medical sponge as a carrier is suitable for monitoring the vacuum drainage status of wounds. The detectable parameters include bleeding volume, drainage pressure, and wound temperature. It is referred to as sensor device B for short.

2. The multimodal sensing system according to claim 1, characterized in that: The mass ratio of the ionic liquid to polyvinylidene fluoride-hexafluoropropylene in the sensor module is (1-4):

1.

3. The multimodal sensing system according to claim 2, characterized in that: The ionic liquid is selected from 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium dicyanamide, and 1-ethyl-3-methylimidazolium chloride.

4. The multimodal sensing system according to claim 3, characterized in that: There are at least two sensing channels between the sensor module and the multimeter; specifically, in the ion gel, the ionic liquid and polyvinylidene fluoride-hexafluoropropylene are in two different proportions, and the two ion gels are respectively arranged between two groups of electrode sheets; the sensing modules corresponding to the ion gels with two different material proportions are recorded as sensing module I and sensing module II; they are used to read voltage signals; the voltage generated by pressure and temperature in the ion gel signals composed of different ion liquid proportions has different proportions, and the voltage signals of the two are decoupled according to the pre-calibrated pressure and temperature coefficients.

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