CN116815416A - Electrostatic perfluorinated polymer fiber membrane, preparation method and application - Google Patents

Abstract

The invention discloses an electrostatic perfluoropolymer fiber membrane, a preparation method and an application, which include the following steps. Step 1: Add perfluoropolymer powder to an organic solvent, heat, stir and dissolve, and leave to stand to obtain an electrospinning precursor. liquid; Step 2: Use a syringe to absorb the electrospinning precursor liquid, and perform electrospinning operations to obtain a perfluoropolymer fiber membrane; Step 3: Dry the perfluoropolymer fiber membrane and place it on a conductor sheet, perform polarization treatment, and obtain a tape Static perfluoropolymer fiber membrane; Step 4: Use the electrostatic perfluoropolymer fiber membrane for wound inflammation and chronic wound repair. The present invention supplements ultrasound during the wound inflammation period to generate ROS at the wound site for sterilization. During the wound appreciation period and remodeling period, the dressing only provides an electrostatic field and relies on the electrostatic field to compensate for the weakened endogenous electric field of the chronic wound site. Antibacterial and electrical stimulation act to promote chronic wound healing.

Description

An electrostatic perfluoropolymer fiber membrane, preparation method and application

Technical field

The invention relates to the technical field of material preparation, and specifically relates to an electrostatically charged perfluoropolymer fiber membrane, a preparation method and application.

Background technique

Studies have shown that when the skin is traumatized, due to the short circuit of endogenous electrical signals, an endogenous electric field directed from the surrounding skin to the center of the wound will be formed to assist in wound healing. Endogenous electrical signals in chronic wounds often Will weaken, resulting in a decrease in self-healing ability.

At present, most of the traditional chronic wound dressings are drug delivery wound dressings, which rely on loaded drugs to treat the wound. However, drug delivery wound dressings often can only rely on loaded drugs to passively promote wound healing, and loaded bactericides Bacterial resistance is easily induced after long-term use, and this strategy ignores the impairment of healing-related cell functions at the wound site due to the weakening of the endogenous electric field. Existing electrical stimulation wound dressings mostly use an external power supply device or a triboelectric nanogenerator. However, this electrical stimulation strategy involves an external circuit, the preparation process is complex, and it is highly irritating to the wound site.

Polyvinylidene fluoride (PVDF) is a commonly used membrane material. PVDF membranes crystallized from solution or molten state can only form a non-polar α-type crystal structure with a helical conformation and no piezoelectric effect. Using electrospinning technology, PVDF is spun into a porous fiber membrane, and the molecular dipole moments of its molecular chains are aligned along the direction of the electric field, thereby obtaining the β crystal form of the all-trans conformation, producing a macroscopic piezoelectric effect. Corona polarization treatment can ionize the air between the two electrodes and generate electron flow through needle tip discharge, and then inject a large number of polarization charges on the surface of the film. Corona polarization of the electrospun polyvinylidene fluoride fiber membrane can further enhance the Its electric dipole moment and improves the stability of the surface potential because electret-induced polarization charges are less affected by ambient humidity than space charges. Electrospinning combined with corona polarization can make the surface of polyvinylidene fluoride film stable for a long time and have a high negative surface potential.

Under the action of ultrasound, the charges in the electrolyte will be adsorbed on the surface of the polymer with piezoelectric effect, and then the adsorbed charges will be released in the form of free charges under the compressive stress induced by ultrasonic cavitation, and interact with water molecules. Or oxygen interacts to generate homogeneous reactive oxygen species (ROS). This effect is called ultrasonic piezoelectric catalysis, and ROS is an excellent bactericidal substance that is not prone to drug resistance. The charged fiber film after electrospinning and polarization treatment has a soft and porous structure and good biocompatibility. Combined with ultrasound, it can simultaneously inhibit bacterial proliferation and has the potential to treat accompanying bacterial infections and endogenous electric fields. Great prospects for weakened chronic wounds.

Contents of the invention

In response to the above problems, the present invention provides a preparation method for an electrostatically charged perfluoropolymer fiber membrane, which includes the following steps:

Step 1: Add the perfluoropolymer powder to the organic solvent, heat and stir to dissolve at a certain water bath temperature, and let it stand to remove bubbles to obtain an electrospinning precursor liquid.

Step 2: Use a syringe to electrospinning the electrospinning precursor in Step 1 under certain electrospinning conditions to obtain a perfluoropolymer fiber membrane.

Step 3: Dry, cut and place the perfluoropolymer fiber membrane prepared in step 2 on a conductor sheet. Perform corona electret treatment by adjusting the high-voltage power supply device to obtain an electrostatically charged perfluoropolymer fiber membrane.

Step 4: Use the electrostatically charged perfluoropolymer fiber membrane obtained in step 3 for wound inflammation and chronic wound repair. During the inflammation phase, ultrasound and charged dressings are applied to the wound at the same time. In the subsequent proliferation and remodeling phases, only charged dressings are applied. fiber membrane.

Further, the perfluoropolymer includes polyvinylidene fluoride, perfluoroethylene propylene copolymer, and polytetrafluoroethylene.

Further, the solvent dissolution temperature in step 1 is 55°C, and the stirring time is 5 hours.

Further, the electrospinning conditions in step 2 are that the relative air humidity is 60, the temperature is 15°C, the voltage is -17kv, and the flow rate is 3.6ml/h.

Further, the conditions for corona electret in step 3 are that the voltage is -8kv and the polarization time is 10 minutes.

Further, in the step 4, during the wound inflammation period, ultrasonic treatment is supplemented, and the conditions are that the ultrasonic power is 2W/cm2 and the ultrasonic time is 15 minutes.

Another aspect of the present invention provides an electrostatically charged perfluoropolymer fiber membrane.

Another aspect of the present invention provides an application of an electrostatically charged perfluoropolymer fiber membrane in wound dressings.

The beneficial effects of the present invention are:

During the wound inflammation phase, ultrasound can be used to generate ROS at the wound site for sterilization. However, during the wound regeneration and remodeling phases, ultrasound is not required. The dressing alone provides an electrostatic field, which relies on the electrostatic field to compensate for the weakened endogenous effects of chronic wounds. Electric fields, combined with the dual effects of antibacterial and electrical stimulation, play a role in promoting the healing of chronic wounds.

Description of the drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present invention and do not limit the present invention. .

Figure 1 is a schematic diagram of the cut fiber membrane of the present invention being placed on a conductor sheet;

Figure 2 Surface potential diagrams of fibers prepared at different flow rates and under different voltage conditions;

Figure 3 Schematic diagram of the relationship between surface potential and polarization time;

Figure 4 Statistics of sterilization efficiency against Escherichia coli (a) and Pseudomonas aeruginosa (b) under different ultrasound powers and against Escherichia coli (c) and Pseudomonas aeruginosa (d) under different ultrasound times;

Figure 5 is a schematic diagram of the crystal form distribution of PVDF electrospun fiber membrane measured by Fourier transform infrared spectroscopy according to the present invention;

Figure 6 is a schematic diagram of the polarization charge amount carried by PVDF of the present invention;

Figure 7 is a schematic diagram of the application of the electrostatically charged PVDF fiber membrane of the present invention in wound dressings;

Figure 8 is a schematic diagram of the present invention establishing a mouse model of diabetic bacterial infection wounds;

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

The present invention will be further described below in conjunction with the accompanying drawings and examples.

A method for preparing an electrostatically charged perfluoropolymer fiber membrane, including the following steps:

Step 1: Add the perfluoropolymer powder to the organic solvent, heat and stir to dissolve at a certain water bath temperature, and let it stand to remove bubbles to obtain an electrospinning precursor liquid.

Among them, perfluoropolymers include polyvinylidene fluoride (PVDF), perfluoroethylene propylene copolymer (FEP), and polytetrafluoroethylene (PTFE). The solvent dissolution temperature is 55°C, and the stirring time is 5 hours.

Step 2: Use a syringe to electrospinning the electrospinning precursor in Step 1 under certain electrospinning conditions to obtain a perfluoropolymer fiber membrane.

The electrospinning conditions were a relative air humidity of 60, a temperature of 15°C, a voltage of -17kv, and a flow rate of 3.6ml/h.

Step 3: Dry the perfluoropolymer fiber membrane prepared in step 2, cut it and place it on the conductor sheet. Perform corona electret by adjusting the high-voltage power supply device to obtain an electrostatically charged perfluoropolymer fiber membrane.

The conditions for corona electret are that the voltage is -8kv and the polarization time is 10min.

Step 4: Use the electrostatically charged perfluoropolymer fiber membrane obtained in step 3 for wound and chronic wound repair. During the inflammation phase, ultrasound and charged dressings are applied to the wound at the same time. In the subsequent proliferation and remodeling phases, only charged fibers are applied. membrane.

During the wound inflammation stage, ultrasonic treatment was supplemented, with the conditions being that the ultrasonic power was 2W/cm ² and the ultrasonic time was 15 minutes.

Example 1

Step 1: Add PVDF powder with a mass fraction of 14% and an average molecular weight of 534,000 to a certain volume of a mixed solution of N,N-dimethylformamide and acetone. Specifically, N,N-dimethylformamide. The volume ratio to acetone is 3:2, then heat and stir at a certain water bath temperature, and let stand to remove bubbles; the water bath temperature is 55°C, and the stirring time is 5 hours.

Step 2: Use a syringe to draw 10 mL of the electrospinning precursor solution from step 1. The outlet end of the syringe is equipped with a 21G metal needle. The needle is connected to a high-voltage power supply device with a conductive metal clip. The syringe is placed on the syringe pump to control the polymer. The solution is pushed out from the tip of the needle at a constant speed at different flow rates, and the voltage of the electrospinning process can be controlled through a high-voltage power supply device; the electrospinning precursor liquid is electrospun under certain electrospinning conditions to obtain a PVDF fiber membrane; The electrospinning conditions are as follows: the relative air humidity is 60, the temperature is 15°C, the voltage is -17kv, and the flow rate is 3.6ml/h.

Step 3: Dry the PVDF fiber membrane prepared in Step 2 and cut it into a 2cm×2cm square and place it on the conductor sheet. As shown in Figure 1, the cut fiber membrane is placed on the conductor sheet (copper sheet). Above the membrane is A metal needle tip with a certain radius of curvature. The upper part of the metal needle tip is connected to a high-voltage power supply device through a metal wire. The conductor sheet is grounded through another metal wire. The vertical distance between the needle tip and the fiber membrane is 4cm. By adjusting the high-voltage power supply device to perform corona electret, an electrostatically charged PVDF fiber membrane is obtained. The conditions for corona electret are that the voltage is -8kv and the polarization time is 10 minutes.

The specific experimental process of the conditions for polarization treatment is to first explore the ability of fiber membranes prepared at different flow rates to store charges under the same polarization time (10 min) and different polarization voltages. As shown in Figure 2, it was found that at 3.6mL/ The fiber prepared at a flow rate of h can reach the highest surface potential (-3889kV) at a polarization voltage of -8kV, and a higher polarization voltage is not conducive to the increase in surface potential after polarization, because deposition on the film surface Excessive space charge may destroy the surface structure of the membrane and cause the electrostatic charge to disappear. Therefore, the fiber prepared at a flow rate of 3.6mL/h was subsequently selected to study the relationship between surface potential and polarization time at -8kV.

As shown in Figure 3, it can be observed that the surface potential of the film rises sharply to -3674kV in the first 3 minutes of polarization and continues to rise after a period of polarization. However, after 12 minutes, the surface potential no longer rises and shows a downward trend. . In summary, a fiber membrane with a flow rate of 3.6 mL/h that was polarized at -8 kV polarization voltage for 10 min was selected for subsequent in vitro and in vivo experiments.

Step 4: Use the electrostatically charged PVDF fiber membrane obtained in step 3 for wound and chronic wound repair. During the inflammation phase, ultrasound and charged dressings are applied to the wound at the same time. In the subsequent proliferation and remodeling phases, only the charged fiber membrane is applied.

The specific ultrasound method is to place the membrane on the skin surface and then place the medical ultrasound probe coated with coupling agent lightly on top of the membrane for ultrasound. The coupling agent and the PVDF membrane are separated by a layer of plastic wrap to prevent the PVDF membrane from contacting the coupling agent. . During ultrasound, the interface between the PVDF membrane and the skin will generate active oxygen free radicals for sterilization. As shown in Figure 4, through quantitative statistics of the number of E. coli and Pseudomonas aeruginosa colonies under different ultrasound powers and ultrasound times after treatment by plate counting, it was found that ultrasound alone has basically no sterilization ability for these two bacteria. In contrast, the sterilization efficiency of PVDF membrane composite ultrasound increases with the increase of ultrasound power and time. When the ultrasound power is 2W/cm ² (duty cycle ≥ 60%), the survival rate of the two bacteria after 15 minutes of ultrasound All dropped to less than 10%, so the ultrasonic conditions during ultrasonic treatment were ultrasonic power of 2 W/cm ² and ultrasonic for 15 minutes. This is because an increase in ultrasonic power can induce greater compressive stress when the tiny bubbles formed by ultrasonic cavitation collapse, increasing the release of free charges to react more fully with water molecules and oxygen molecules. In addition, extending the ultrasonic time can accumulate and generate more ROS in the solution, thereby improving the sterilization efficiency.

When PVDF dissolved in organic matter is ejected from the metal needle of the syringe, the high-voltage electric field fully orients the originally randomly oriented molecular dipole moments along the direction of the electric field, inducing an all-trans conformation β crystal form. Transition to the α crystalline form of helical conformation. As shown in Figure 5, the crystal form distribution of the PVDF electrospun fiber membrane was measured through Fourier transform infrared spectroscopy, and based on the data chart, it was deduced that the relative content of the β crystal form in the PVDF electrospun fiber membrane was as high as 84.8%, which shows that the system The obtained PVDF fiber membrane has excellent piezoelectric effect and has the potential to become an electret capable of storing charges for a long time.

As shown in Figure 6, by adjusting the time and parameters of corona polarization, the amount of polarized charge carried by PVDF is further increased, resulting in a higher surface potential than the PVDF fiber membrane directly peeled off after electrospinning. And it has a slower charge decay trend under different humidity. This is because PVDF has abundant fluorocarbon chain segments, and fluorine atoms have extremely strong electronegativity. The two high-voltage electric fields of electrospinning and corona polarization generate abundant polarization dipoles, which increases The charge content belonging to the polarization charge is reduced, resulting in a higher negative surface polarization potential that is not easily attenuated.

As shown in Figure 7, this material can generate a sustained and stable electrostatic field near the wound in a direction directed from normal skin to the wound, thereby making up for the lack of endogenous electric field in chronic diabetic wounds, and the enhanced electric field at the wound site can pass through Regulate healing-related cell behaviors to promote wound healing. At the same time, the piezoelectric PVDF fiber membrane carrying a large amount of polarized charges can produce ROS through the ultrasonic piezoelectric catalytic effect with the assistance of ultrasound, thereby achieving a bactericidal effect.

Compared with the existing technology, this new type of charged dressing enhances the stability and intensity of its surface potential by electretizing the PVDF electrospun membrane, and using the electrostatic field as the external electrical stimulation can be used without the need for an external circuit. It assists wound healing by enhancing the endogenous electric field of the wound surface, and is less irritating to the wound. At the same time, the addition of an ultrasound source can promote the generation of ROS without the addition of drugs, which has a bactericidal effect and prevents bacterial infection at the wound site. As shown in Figure 8, by establishing a mouse model of diabetic bacterial infection wounds, it was verified that this strategy can achieve a wound closure rate of close to 100% within a 12-day treatment cycle, and no wounds caused by bacterial infection occurred during the monitoring process. Suppuration phenomenon.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Although the present invention has been disclosed above in preferred embodiments, they are not intended to limit the present invention. Anyone familiar with this field will Skilled persons can make some changes or modifications to equivalent embodiments using the technical content disclosed above without departing from the scope of the technical solution of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the invention still fall within the scope of the technical solution of the present invention.

Claims (8)

1. The preparation method of the electrostatically charged perfluorinated polymer fiber membrane is characterized by comprising the following steps of:

step 1: adding perfluorinated polymer powder into an organic solvent, heating, stirring and dissolving at a certain water bath temperature, and standing to remove bubbles to obtain an electrostatic spinning precursor solution;

step 2: carrying out electrostatic spinning operation on the electrostatic spinning precursor liquid in the step 1 under a certain electrostatic spinning condition by using an injector to obtain a perfluorinated polymer fiber membrane;

step 3: drying and cutting the perfluorinated polymer fiber membrane prepared in the step 2, placing the perfluorinated polymer fiber membrane on a conductor sheet, and carrying out corona electret treatment by adjusting a high-voltage power supply device to obtain the perfluorinated polymer fiber membrane with static electricity;

step 4: and (3) applying the electrostatic perfluorinated polymer fiber membrane obtained in the step (3) to wound inflammation and chronic wound repair, applying ultrasonic and charged dressing to the wound simultaneously in the inflammation stage, and only applying the charged fiber membrane in the subsequent proliferation stage and remodelling stage.

2. The method for preparing an electrostatically charged perfluoro polymer fiber membrane according to claim 1, wherein said perfluoro polymer comprises polyvinylidene fluoride, a perfluoro ethylene propylene copolymer, polytetrafluoroethylene.

3. The method for preparing an electrostatically charged perfluorinated polymer fiber membrane according to claim 1, wherein the solvent dissolution temperature in the step 1 is 55 ℃, and the stirring time is 5 hours.

4. The method for preparing an electrostatically charged perfluorinated polymer fiber membrane according to claim 1, wherein the electrostatic spinning condition in the step 2 is that the relative air humidity is 60, the temperature is 15 ℃, the voltage is-17 kv, and the flow rate is 3.6ml/h.

5. The method for preparing an electrostatically charged perfluorinated polymer fiber membrane according to claim 1, wherein the condition of corona electret in the step 3 is that the voltage is-8 kv and the polarization time is 10min.

6. The method for preparing an electrostatically charged perfluorinated polymer fiber membrane according to claim 1, wherein in said step 4, ultrasound treatment is used as auxiliary material in the inflammation stage of the wound, provided that the ultrasound power is 2W/cm ² The ultrasonic time was 15min.

7. An electrostatically charged perfluorinated polymer fiber membrane manufactured by the method for manufacturing an electrostatically charged perfluorinated polymer fiber membrane according to any one of claims 1 to 6.

8. An electrostatically charged perfluorinated polymeric fiber membrane according to claim 7, for use in a wound dressing.