CN112704488B - Wound damage state monitoring devices based on flexible ventilative hydrogel membrane - Google Patents
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
- A61B5/107—Measuring physical dimensions, e.g. size of the entire body or parts thereof
- A61B5/1077—Measuring of profiles
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
- A61B5/053—Measuring electrical impedance or conductance of a portion of the body
- A61B5/0537—Measuring body composition by impedance, e.g. tissue hydration or fat content
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
- A61B5/107—Measuring physical dimensions, e.g. size of the entire body or parts thereof
- A61B5/1073—Measuring volume, e.g. of limbs
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/02—Details of sensors specially adapted for in-vivo measurements
- A61B2562/0209—Special features of electrodes classified in A61B5/24, A61B5/25, A61B5/283, A61B5/291, A61B5/296, A61B5/053
- A61B2562/0217—Electrolyte containing
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/02—Details of sensors specially adapted for in-vivo measurements
- A61B2562/0261—Strain gauges
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/02—Details of sensors specially adapted for in-vivo measurements
- A61B2562/029—Humidity sensors
Abstract
The invention discloses a wound damage state monitoring device based on a flexible breathable hydrogel film. The CNTs/graphene/GelMA electrospun membrane in dry and wet states is used and serves as a dual-function sensor for wound exudate sensing and strain sensing after being packaged by a breathable membrane, the sensor is in direct contact with a wound, the exudate volume of tissue fluid and wound deformation at the wound can be converted into electric signals through a voltage division circuit, and the electric signals are detected by a portable oscilloscope, so that the wound damage condition can be accurately monitored in real time.
Description
Technical Field
The invention relates to medical risk monitoring of postoperative wounds by using a flexible sensor, in particular to a device for monitoring the wound damage state based on a flexible breathable hydrogel film.
Background
It is clinically necessary to monitor the occurrence of a major surgical wound that is damaged by the forces exerted on the surrounding tissues during the recovery period. For example, in one month after the cesarean section of a parturient, rehabilitation training for organ homing needs to be carried out autonomously or with the assistance of external force, and symptoms such as cough, nausea and vomiting can occur in the recovery process, which can cause the deformation of a wound surface and even lead a suture to be broken, thereby not only affecting the healing effect of a surgical wound, but also causing severe pain and increasing the infection risk after the surgical wound is broken. But traditional closely knit wound wraps and is unsuitable for the macroscopic observation wound to change, and the stereoplasm sensor of commercialization can bring mechanical strength mismatch, gas permeability poor, uncomfortable scheduling problem as monitoring tool, is unfavorable for wearing for a long time.
The flexible wearable equipment has the characteristics of wearability, comfortableness, remote operation, timely feedback and the like, and a core element of the flexible wearable equipment is a sensor capable of meeting the detection requirements of certain physiological and pathological indexes. For example, chinese patent 201910457555.1 proposes carbon nanotube/polydimethylsiloxane fibers for strain sensors. For monitoring the damage of the operation wound, the corresponding sensor also meets the basic requirements of the dressing, and simultaneously, the qualitative or quantitative detection capability for the wound exudate is required. For example, chinese patent 201780050186.3 proposes a visual indicator system for wound condition determination using a gemma/chromogenic microsphere/photoinitiator mixture and formed by curing deposition onto Orion nonwoven material, wherein the gemma can be degraded by specific enzymes in the wound exudate to induce directional flow of the chromogenic microspheres. But the problem lies in this system can't realize continuous monitoring because there is structural loss, and the interpretation of colour signal itself has human error to disturb, and wound is wrapped and is also unfavorable for its play.
At present, based on the advantages of gemma in biocompatibility, a composite hydrogel matrix with good conductivity, mechanical stability and high load capacity is obtained by doping CNTs or graphene in a crosslinking process and utilizing a porous structure formed by crosslinking, for example, chinese patents 201910072582.7 and 201911129801.7. These matrix materials do not exhibit sensing capabilities in terms of strain, change in wetness, etc.
Disclosure of Invention
The invention aims to provide a wound damage state monitoring device based on a flexible breathable hydrogel film, which can realize real-time and accurate monitoring of wound stress deformation and wound tissue fluid exudation volume and has the characteristic of simple operation.
In order to achieve the purpose, the invention adopts the following technical scheme:
the wound damage state monitoring device comprises a sensing module and a detection module, wherein the sensing module comprises more than one variable resistance type flexible sensing unit, the flexible sensing unit is divided into a strain sensing unit and a exudate sensing unit, the flexible sensing unit (the strain sensing unit and/or the exudate sensing unit) comprises a composite methacrylamide gelatin (GelMA) hydrogel film loaded with Carbon Nano Tubes (CNTs) and graphene, and the detection module comprises a circuit element and an electric signal detection device (for example, a touch screen type oscilloscope) which are used for converting resistance change of the flexible sensing unit caused by self strain and/or wetting degree change into corresponding electric signals.
Preferably, the composite methacrylamide gelatin (GelMA) hydrogel membrane is prepared by fixing Carbon Nanotubes (CNTs) and graphene on the porous structure of a methacrylamide gelatin (GelMA) hydrogel matrix.
Preferably, the methacrylamide gelatin (GelMA) hydrogel matrix is selected from a methacrylamide gelatin (GelMA) hydrogel electrospun membrane, the methacrylamide gelatin (GelMA) hydrogel electrospun membrane is subjected to ultraviolet crosslinking and freeze drying treatment before being compounded with Carbon Nanotubes (CNTs) and graphene, and the thickness of the composite methacrylamide gelatin (GelMA) hydrogel membrane (for example, the CNTs/graphene/GelMA electrospun membrane) is 10-100 μm.
Preferably, the compounding specifically comprises the following steps: and (2) placing the dried porous electrospun membrane (namely the methacrylamide gelatin hydrogel electrospun membrane which is subjected to ultraviolet crosslinking and freeze drying) into the carbon nanotube-graphene-chitosan mixed slurry for ultrasonic treatment, and then taking out and airing (so as to obtain the dried CNTs/graphene/GelMA electrospun membrane).
Preferably, the carbon nanotube-graphene-chitosan mixed slurry is prepared by mixing a binary mixed solution consisting of 0.5-2 mL of graphene aqueous solution and 0.4-0.6 mL of chitosan solution with less than or equal to 0.05g of Carbon Nanotubes (CNTs); the mass fraction of the graphene aqueous solution is 1% -5% (which can be obtained by further diluting purchased water-soluble graphene), and the mass fraction of the chitosan solution is 0.5% -1%.
Preferably, the flexible sensing unit further comprises an encapsulation film layer (for example, a medical breathable film is used to form a double-sided encapsulation or a single-sided encapsulation) disposed on two sides or one side of the composite methacrylamide gelatin (GelMA) hydrogel film.
Preferably, the circuit element and the flexible sensing unit are connected in series to form a voltage dividing circuit.
Preferably, the detection device is connected to the high and low potential end points of the flexible sensing unit respectively (for example, the flexible sensing unit is connected in parallel to two ends of an oscilloscope).
Preferably, the detection module further comprises a power supply for supplying power to the voltage division circuit.
Preferably, the wound breakage state monitoring device further comprises a mobile terminal remotely connected with the detection device.
Preferably, the sensing module specifically includes more than one strain sensing unit and more than one exudate sensing unit, the strain sensing unit includes a fully wetted (for example, using water or physiological saline) composite methacrylamide gelatin (GelMA) hydrogel film loaded with Carbon Nanotubes (CNTs) and graphene (and adopting double-sided encapsulation), the exudate sensing unit includes a non-wetted composite methacrylamide gelatin (GelMA) hydrogel film loaded with Carbon Nanotubes (CNTs) and graphene (and adopting single-sided encapsulation), and each sensing unit is independent of each other.
The invention has the beneficial effects that:
according to the invention, a composite flexible breathable hydrogel film composed of CNTs, graphene and GelMA is used as a core element of a variable resistance type flexible sensing unit, the sensing unit is stretched to different degrees according to the found wound deformation, and when the sensing unit is wetted by wound exudates to different degrees, the resistance of the sensing unit is correspondingly changed, and the resistance change of the sensing unit is converted into corresponding electric signals (for example, partial pressure at two ends) and detected, so that the resistance change condition (for example, the resistance change condition can be displayed on a parallel oscilloscope) can be intuitively reflected, and the variable resistance type flexible sensing unit can be used for monitoring the actual state (for example, damage) of a wound. The invention has small size, low cost and strong practicability, and can be used as a monitoring device for home recovery after operation.
Furthermore, GelMA is prepared into an electrospinning membrane, the flexibility and the air permeability of the membrane are enhanced by adopting ultraviolet crosslinking, and a macroporous structure is formed after freeze drying to enhance the adsorption performance of the membrane, so that graphene and CNTs are fixed on the pore wall of the GelMA hydrogel porous structure by utilizing the membrane forming effect of chitosan. In addition, the composite flexible breathable hydrogel film has excellent strain performance by controlling the film thickness.
Furthermore, the strain sensing unit is formed by packaging the wetted CNTs/graphene/GelMA electrospun membrane on two sides of a medical breathable membrane, so that rapid evaporation of moisture can be avoided, the wound can be breathable, and the wound drying environment is kept, thereby being beneficial to reducing the risk of contamination. The exudate sensing unit is formed by packaging a dry CNTs/graphene/GelMA electrospun membrane with a medical breathable membrane, so that the sensor is prevented from being torn due to excessive stress, and the inside of the exudate sensing unit is directly contacted with a wound surface to conveniently absorb exudate.
Furthermore, the strain sensing unit and the exudate sensing unit are respectively and vertically fixed with the wound and respectively form independent voltage division circuits, the two circuits are in parallel connection, and test results are respectively recorded. The combination of the strain sensing unit and the exudate sensing unit can simultaneously detect the deformation degree of a wound surface and the volume of exudate, and reflect the recovery condition of the wound and the damage condition after stress in a plurality of aspects.
Furthermore, the CNTs/graphene/GelMA electrospun membrane is tested for the influence of the wetting degree on the resistance thereof in a dry state, and the result shows that the volume of liquid for wetting the membrane and the change of the resistance are 0-0.37 mu L/mm2Is linear in the range of the degree of wetting.
Furthermore, the CNTs/graphene/GelMA electrospun membrane tests the influence of strain on the resistance in a completely wetted state, and the stretching degree and the resistance change of the membrane are in linear relation within the range of 0-70% and 70-85% respectively.
Furthermore, the touch-screen oscilloscope is small in size and light in weight, can be connected with mobile terminals such as mobile phones through WiFi, and is more suitable for monitoring wound dynamics and feeding back doctors at home compared with large-scale detection equipment.
Furthermore, the amount of carbon nanotubes is strictly controlled (preferably 0.04 g), and when the amount is too large, the carbon nanotubes may fall off from the CNTs/graphene/GelMA electrospun membrane, so that the air permeability is deteriorated, the electrical conductivity is also reduced, and when the amount is too small, the electrical conductivity is more remarkably reduced.
Drawings
FIG. 1 is a scanning electron micrograph (a) and a cross section (b) of a CNTs/graphene/GelMA electrospun membrane prepared in example 1.
FIG. 2 shows the results of the permeability test of the CNTs/graphene/GelMA electrospun membrane prepared in example 1.
Fig. 3 is a schematic block diagram showing the structure of the sensor device for monitoring the state of wound damage in embodiment 1.
FIG. 4 is a schematic diagram of a signal detection model of the voltage divider circuit shown in FIG. 3; wherein R is a variable resistance, R1Is a constant value resistor, V is an oscilloscope, U is a voltage signal, and E is a power supply.
FIG. 5 shows the elongation (strain) and the rate of change of resistance (rate of change of resistance: resistance of each point of resistance R relative to its initial resistance R of the CNTs/graphene/GelMA electrospun membrane prepared in example 10The variation Δ R and the initial resistance value R0Ratio (c) of the relationship.
FIG. 6 is a graph showing the relationship between the degree of wetting and the rate of change of resistance of the CNTs/graphene/GelMA electrospun membrane prepared in example 1.
Fig. 7 is a schematic diagram of the application principle of the flexible breathable hydrogel film.
Detailed Description
The present invention is further described in detail with reference to the drawings and examples, which are described in order to enable those skilled in the art to better understand the technical solutions of the present invention and should not be construed as limiting the scope of the present invention.
Example 1
Synthesis of GelMA
100mL of PBS (pH 7) buffer was stirred and heated to 60 ℃, and 10g of gelatin was slowly added during the stirring and heating to completely dissolve it, to obtain a gelatin solution. Dropwise adding 8mL of methacrylic anhydride into the gelatin solution, keeping the temperature at 60 ℃, and continuously heating and stirring for 3 hours in the dark to obtain a reaction solution. The reaction solution was diluted with 400mL of PBS (pH 7) buffer previously warmed to 50 ℃. Transferring the diluted reaction solution containing the synthesized GelMA into a dialysis membrane, sealing the membrane, and dialyzing the membrane in 5L of deionized water at 50 ℃ in the dark for one week to remove unreacted methacrylic anhydride to obtain a GelMA solution. Freezing the GelMA solution obtained after dialysis at-80 deg.C for 24h, and freeze drying at (-80 deg.C, vacuum degree of 0.1MPa) for 4 days to obtain spongy GelMA solid.
Preparation of (II) GelMA electrospun film
0.5g of the GelMA solid obtained in (I) was dissolved in 5mL of hexafluoroisopropanol to obtain a transparent liquid. Transferring the transparent liquid into an injector, fixing the injector on a mobile device of an electrospinning machine, connecting a metal needle with a connector with high potential of a power supply, setting the flow rate of 0.6mL/h and the voltage of 15kV, adjusting the position of the metal needle to align the metal needle with a receiving plate, controlling the distance between the metal needle and the receiving plate to be about 15cm, and wrapping tin foil paper on the receiving plate and connecting the metal needle with the connector with low potential of the power supply. And closing the glass cabin door, and opening a power switch to form a 15kV potential difference between the metal needle head and the receiving plate, so that the liquid is ejected out of the injector in a fibrous shape and the prepared electrospinning film is collected on the receiving plate. Soaking the prepared electrospun membrane in photoinitiator solution (2-hydroxy-2-methyl propiophenone absolute ethanol solution with volume fraction of 10%) for 2h, placing the electrospun membrane together with the photoinitiator solution in a box-type ultraviolet crosslinking instrument, and crosslinking for 45min under the ultraviolet light (UV) with the wavelength of 365 nm. And taking out the crosslinked electrospun membrane, washing the electrospun membrane by using ethanol and deionized water, and soaking the electrospun membrane in the deionized water overnight. Freezing the cleaned GelMA electrospun membrane at-80 deg.C for 24h, and freeze-drying at-80 deg.C under vacuum degree of 0.1MPa for 2 days to obtain dried porous electrospun membrane.
Preparation and characterization of (tri) CNTs/graphene/GelMA electrospun membrane
Firstly, 1mL of graphene water solution with the mass fraction of 5% and 0.5mL of chitosan-acetic acid solution with the mass fraction of 1% (1g of chitosan is added into 100mL of acetic acid solution with the volume fraction of 1%) are taken to prepare a mixed solution, then 0.04g of CNTs (the diameter is 10-20 nm, the length is 10-30 mu m) are added into the mixed solution, and the mixed solution is subjected to ultrasonic treatment (100W) for 30min at room temperature to obtain the CNTs-graphene-chitosan mixed slurry.
And (3) cutting the dried porous electrospinning membrane prepared in the step (II), placing the cut porous electrospinning membrane into the CNTs-graphene-chitosan mixed slurry, and performing ultrasonic treatment (100W) for 10min at room temperature to disperse the CNTs and graphene which are conductive substances into pores of the electrospinning membrane. Taking out and naturally drying, and forming chitosan in situ along with the evaporation of water and the volatilization of acetic acid, so that the CNTs and graphene are fixed on the surface and in pores of the electrospun membrane, and the dried CNTs/graphene/GelMA electrospun membrane is obtained.
Scanning electron microscope tests show that the surface morphology of the CNTs/graphene/GelMA electrospun membrane shows graphene flakes and a network structure formed by the CNTs, wherein the graphene flakes and the network structure are fixed by chitosan to form a flaky morphology and a network-alternated morphology, and the network structure is helpful for keeping the air permeability of the CNTs/graphene/GelMA electrospun membrane (as shown in FIG. 1 a). The cross-sectional morphology of the CNTs/graphene/GelMA electrospun membrane shows that the GelMA porous structure scaffold and the CNTs/graphene composites (referred to as CNTs and graphene) immobilized on the surface and inside through chitosan have a total membrane thickness of about 30 μm (as shown in FIG. 1 b).
Quantitative test of air permeability: the prepared CNTs/graphene/GelMA electrospun membrane is attached to a glass bottle mouth filled with water, the weight change of the water in the glass bottle is measured every 1h at 37 ℃, a 12h Water Vapor Transmission Rate (WVTR) curve (shown in figure 2) is obtained, and the WVTR is 554.3 g.h through calculation-1·m-2. The combination of the test results of a scanning electron microscope shows that the prepared CNTs/graphene/GelMA electrospun membrane is a flexible breathable hydrogel membrane formed by CNTs and graphene and GelMA electrospun membranes, and the flexible breathable hydrogel membrane has a square resistance value of 150 omega-sq without tensile deformation through determination-1The water absorption rate is 300-500%.
(IV) manufacturing a sensing unit based on a flexible breathable hydrogel film
A piece of dry CNTs/graphene/GelMA electrospun membrane is taken, two ends of the dry CNTs/graphene/GelMA electrospun membrane are fixed with a thin conducting wire (an enameled wire with the diameter of about 100 mu m) by using conductive adhesive, and the membrane is completely wetted by water and then packaged by double-sided bonding of a soft elastic transparent medical waterproof breathable membrane (the Young modulus is close to that of the completely wetted CNTs/graphene/GelMA electrospun membrane and can be deformed at the same time). The electrospun membrane in a wet state is used for constructing a strain sensing unit because of better flexibility and elasticity. The effect of strain on the resistance of the CNTs/graphene/GelMA electrospun membrane in a completely wetted state is tested, and the result shows that the stretching degree of the membrane is in a linear relationship with the resistance change thereof in the range of 0-70% and 70-85%, respectively (as shown in FIG. 5), and the strain coefficients (the resistance change rate under unit strain) are 15.4 and 72.9, respectively. The two strain ranges correspond to the normal stretching range and the broken stretching range of the skin (see Wang et al adv. mater.2020,2003014), respectively, and can be used to qualitatively determine whether a wound is broken or not.
And (3) another piece of the dried CNTs/graphene/GelMA electrospun membrane is taken, two ends of the dried CNTs/graphene/GelMA electrospun membrane are fixed with thin wires (enameled wires with the diameter of about 100 mu m) by using conductive adhesive, the enameled wires are kept dry (without water infiltration), and then the enameled wires are bonded and packaged by using a soft elastic transparent medical waterproof breathable membrane on one side (the side which is not packaged faces to a wound) to form a exudate sensing unit. The influence of the wetting degree on the resistance is tested under the condition that the dried CNTs/graphene/GelMA electrospun membrane absorbs water in a gradient way, and the result shows that the water absorption volume is 0-0.37 mu L/mm2Is linearly related to its resistance change (as shown in fig. 6).
(V) monitoring wound damage state's sensing device
Referring to fig. 3, the sensing device mainly comprises a voltage divider circuit and a portable detection device, wherein the voltage divider circuit comprising the strain sensing unit and the voltage divider circuit comprising the exudate sensing unit can be provided with voltage input by a power supply. Each voltage division circuit realizes real-time detection of voltage signals of the contained sensing units through portable detection equipment (such as a touch screen type oscilloscope), and the change of the voltage signals is in positive correlation with the change of the resistance values of the corresponding sensing units.
The voltage division circuit and the portable detection device are specifically mounted and connected as follows:
the two ends of the strain sensing unit (the leads are connected with the two ends of the corresponding sensing unit respectively through packaging) are fixed on the skin on the two sides of the wound respectively, the middle part of the strain sensing unit covers one section of suture area of the wound, the exudate sensing unit integrally covers the other section of suture area of the wound, and the soft elastic transparent medical waterproof breathable film is adopted for fixing the corresponding sensing unit on the skin near the wound, and the specific circuit connection refers to fig. 4. Each sensing unit is used as a variable resistor and is respectively connected with a constant value resistor with a certain resistance value in series through a lead, so that each voltage division circuit powered by a power supply is constructed, two groups of probes of the touch screen type oscilloscope are respectively connected with two ends of the strain sensing unit and two ends of the exudate sensing unit,for simultaneously testing the partial pressure change at both ends of the sensing unit. Using the first read voltage value for calculating or calibrating R0Therefore, the change of the resistance value of the sensing unit can be calculated by referring to the voltage of the constant-value resistor in the same voltage division circuit, so as to evaluate the deformation degree of the wound in the recovery period (for example, cracking caused by stress) and the exudation condition of the wound tissue fluid (for example, the volume of the exudation fluid). The touch screen type oscilloscope can also be connected with mobile terminal equipment such as a mobile phone and the like through WiFi to carry out remote control and reading.
(VI) sensing device for monitoring wound damage state
Referring to fig. 7, after a lying-in woman receives a cesarean section, the lying-in woman needs to perform organ homing rehabilitation training autonomously or with the assistance of external force, and skin strain caused by organ movement or external force extrusion easily tears a surgical wound due to a large wound surface, so that the wound is cracked due to excessive stress or the wound is damaged to flow out tissue fluid. However, it is not easy to observe the change of the wound state with naked eyes under the gauze covering state, so that a dual-function sensor with strain sensing and exudate sensing is needed for monitoring the wound state and warning.
The sensing unit of the dual-function sensor is divided into a strain sensing unit and an exudate sensing unit which respectively cross the wound and are attached to the skin, and the strain sensing unit and the exudate sensing unit are fixed by using the adhesive tape formed by cutting the medical waterproof breathable film. The strain sensing unit and the exudate sensing unit are respectively connected with a constant value resistor through enameled wires to form two voltage division circuits (the two circuits are in parallel connection and powered by a constant voltage power supply), the voltage division change of two ends of the corresponding sensing unit is respectively detected by using two channels of a touch screen type oscilloscope (voltage signals at two ends of the sensing unit are collected, and the result is respectively recorded), and the resistance change of the corresponding sensing unit caused by the change of strain and the wetting degree is obtained through calculation and analysis, so that the deformation and the exudate volume of tissue fluid of the corresponding sensing unit close to the wound caused by the action of external force on the vicinity of the wound are reflected. The mobile phone terminal can be connected with the touch screen type oscilloscope through WIFI, so that the oscilloscope can be conveniently controlled remotely and in real time by using the APP, and a detection result can be displayed.
In practical application, because the wound sutured after the caesarean section is usually in a long strip shape, and the deformation of the middle part is relatively large, the strain sensing unit is arranged in the middle part of the wound, and one or more groups of exudate sensing units can be properly added beside the strain sensing unit so as to find the change of the wound in time before the pain and warn the possible danger of the wound. For example, when the strain sensing unit is displayed on an oscilloscope beyond the set 70% range, a wound tearing risk may occur (as shown in fig. 5). Whether liquid (such as tissue fluid) seeps out of the wound and the seepage amount is judged by continuously observing whether the corresponding signals of the seepage sensing unit linearly change or not, when the seepage sensing unit absorbs the liquid to be saturated (completely infiltrated), the linear curve is suddenly increased and then tends to be stable (as shown in figure 6), and at the moment, the puerpera can feel obvious pain. Therefore, the wound state can be judged according to the feedback of the oscilloscope, and the wound is timely treated before the exudate sensing unit is completely wetted, so that excessive pain and secondary infection caused by excessive exudate are avoided. In the subsequent development of finished products of the device, corresponding alarm modules can be arranged at corresponding signal nodes when the stretching amount of 70 percent and the absorption of exuded liquid are saturated, so as to remind the user to adjust the force in time.
Example 2
Compared to example 1, the preparation of CNTs/graphene/GelMA electrospun membranes presented a difference in the amount of CNTs:
preparing a mixed solution from 1mL of 5% graphene aqueous solution and 0.5mL of 1% chitosan-acetic acid solution, then adding 0.01g of CNTs into the mixed solution, and performing ultrasonic treatment (100W) for 30min at room temperature to obtain CNTs-graphene-chitosan mixed slurry.
Compared with the CNTs/graphene/GelMA electrospun membrane prepared in the example 1, the CNTs/graphene/GelMA electrospun membrane prepared in the example 2 has a square resistance value of 250 omega-sq without tensile deformation-1A significant increase in the square resistance value indicates a poorer conductivity than in example 1. And in the range of 0-70%, the strain coefficient is 9.32, which is smaller than that of example 1, indicating that the strain performance of the strain sensor is relatively poor.
In summary, the present invention is directed to the wound deformation and the liquid exudation phenomenon in the wound that can occur after the cesarean section, and the corresponding sensing units are used to monitor the wound of the parturient in real time from two aspects, which is beneficial to the postoperative recovery of the parturient, and is also suitable for the postoperative wound risk monitoring of other types of operations (for example, organ transplantation) that can occur stress influence.
Claims (8)
1. The utility model provides a wound damage state monitoring devices based on flexible ventilative hydrogel membrane which characterized in that: the wound damage state monitoring device comprises a sensing module and a detection module, wherein the sensing module comprises more than one variable resistance type flexible sensing unit, the flexible sensing unit comprises a composite methacrylamide gelatin hydrogel film loaded with carbon nano tubes and graphene, the composite methacrylamide gelatin hydrogel film is formed by compounding carbon nano tubes and graphene loaded on a porous structure of a methacrylamide gelatin hydrogel matrix prepared by electrostatic spinning through carbon nano tube-graphene-chitosan mixed slurry, and the detection module comprises a circuit element and an electric signal detection device, wherein the circuit element is used for converting resistance change of the flexible sensing unit caused by self strain and/or wetting degree change into corresponding electric signals.
2. A wound breakage status monitoring device based on a flexible gas permeable hydrogel membrane according to claim 1, wherein: the flexible sensing unit further comprises packaging film layers arranged on two sides or one side of the composite methacrylamide gelatin hydrogel film.
3. A wound breakage status monitoring device based on a flexible gas permeable hydrogel membrane according to claim 1, wherein: the circuit element and the flexible sensing unit are connected in series to form a voltage division circuit.
4. A wound breakage status monitoring device based on a flexible gas permeable hydrogel membrane according to claim 3, wherein: the detection equipment is respectively connected with the high and low potential end points of the flexible sensing unit.
5. A wound breakage status monitoring device based on a flexible gas permeable hydrogel membrane according to claim 1, wherein: the wound breakage state monitoring device further comprises a mobile terminal remotely connected with the detection equipment.
6. A wound breakage status monitoring device based on a flexible gas permeable hydrogel membrane according to claim 1, wherein: the sensing module comprises more than one strain sensing unit and more than one exudate sensing unit, wherein the strain sensing unit comprises a wetted composite methacrylamide gelatin hydrogel film loaded with carbon nanotubes and graphene, and the exudate sensing unit comprises an unwetted composite methacrylamide gelatin hydrogel film loaded with carbon nanotubes and graphene.
7. A flexible breathable hydrogel film characterized by: the flexible breathable hydrogel film is a composite methacrylamide gelatin hydrogel film, the composite methacrylamide gelatin hydrogel film is formed by compounding a carbon nano tube and graphene loaded on a porous structure of a methacrylamide gelatin hydrogel matrix through carbon nano tube-graphene-chitosan mixed slurry, graphene flakes on the surface of the composite methacrylamide gelatin hydrogel film and a network structure formed by the carbon nano tubes are fixed by chitosan to form a sheet shape and a network-alternated shape, and the thickness of the composite methacrylamide gelatin hydrogel film is 10-100 micrometers;
the methacrylamide gelatin hydrogel matrix is selected from a methacrylamide gelatin hydrogel electrospun membrane;
the compounding specifically comprises the following steps: placing the methacrylamide gelatin hydrogel electrospun membrane subjected to ultraviolet crosslinking and freeze drying in the carbon nanotube-graphene-chitosan mixed slurry for ultrasonic treatment, and then drying.
8. The flexible, breathable hydrogel film of claim 7, wherein: the carbon nanotube-graphene-chitosan mixed slurry is prepared by mixing a binary mixed solution consisting of 0.5-2 mL of graphene aqueous solution and 0.4-0.6 mL of chitosan solution with less than or equal to 0.05g of carbon nanotubes; the graphene aqueous solution comprises 1-5% by mass of a chitosan solution and 0.5-1% by mass of a graphene aqueous solution.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011445956.4A CN112704488B (en) | 2020-12-11 | 2020-12-11 | Wound damage state monitoring devices based on flexible ventilative hydrogel membrane |
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