Enhanced antibacterial hybrid phase-transition porous fiber membrane and preparation method and application thereof

Abstract

The application belongs to the field of biomedicine, and discloses a hybrid phase change porous fiber membrane with enhanced antibacterial property and a preparation method and application thereof. The hybrid phase change porous fiber membrane with enhanced antibacterial property comprises a multi-stage porous carbon fiber membrane, a phase change material, tannic acid (TA) and metal nano-enzyme loaded on the multi-stage porous carbon fiber membrane; wherein the multi-stage porous carbon fiber membrane is prepared by mixing ZIF-67 nanoparticles and polyacrylonitrile, and then performing electrospinning, pre-oxidation and calcination. The hybrid phase change porous fiber membrane with enhanced antibacterial property has excellent antibacterial property and wound healing promotion property.

Description

Technical Field

[0001] This invention belongs to the field of biomedicine, and specifically relates to a hybrid phase change porous fiber membrane with enhanced antibacterial properties, its preparation method, and its application. Background Technology

[0002] The skin, the largest organ in the human body, acts as a barrier, protecting the body from the invasion of exogenous microorganisms and pathogens. When a wound becomes infected with bacteria, it easily triggers an inflammatory response, thus hindering the basic process of wound healing. Therefore, the effective and safe healing of bacterial-infected wounds is a significant clinical challenge. Currently, wound dressings are mainly used clinically to promote wound healing. Traditional wound dressings (bandages and gauze, etc.) are prone to tissue adhesion when in contact with the wound for extended periods, causing pain and bleeding during dressing changes, resulting in secondary damage, and they lack antibacterial and healing-promoting functions. Therefore, the development of novel multifunctional wound dressings has become a research hotspot. With the advancement of nanotechnology and biomaterials science, electrospun fiber dressings, due to their high porosity, high specific surface area, and extracellular matrix (ECM)-like structure, show broad application prospects in the treatment of bacterial-infected wounds.

[0003] Electrospinning is a technique with highly controllable parameters, a simple process, and the ability to directly, continuously, and efficiently prepare micro / nanofibers, while also allowing for the control of their morphology, structure, and size. By optimizing the spinning process, porous fibers with higher specific surface areas, more active sites, and richer pore structures can be produced, thereby accelerating the diffusion, transport, or transformation of substances and finding wide applications in many fields. For example, in the biomedical field, porous nanofibers, due to their high specific surface area, possess excellent loading and delivery capabilities for substances. They can be used to inactivate bacteria by loading antibacterial agents, and by loading phase change materials, utilizing the photothermal conversion properties of porous carbon fibers to achieve photocontrolled drug release, making it an effective solution for preparing novel multifunctional wound dressings.

[0004] Currently, some antimicrobial therapies have become cutting-edge treatment strategies for bacterial infections, such as photothermal therapy (PTT), chemodynamic therapy (CDT), photodynamic therapy (PDT), and metal ion therapy (MIT). However, due to the different antimicrobial mechanisms, single-modality antimicrobial therapies have certain limitations in the treatment of infected wounds. Therefore, there is an urgent need to develop novel wound dressings with multimodal antimicrobial capabilities. Summary of the Invention

[0005] In order to overcome the shortcomings and deficiencies of the prior art, the primary objective of the present invention is to provide a hybrid phase change porous fiber membrane with enhanced antibacterial properties.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned hybrid phase change porous fiber membrane with enhanced antibacterial properties.

[0007] Another object of the present invention is to provide the application of the above-mentioned enhanced antibacterial hybrid phase change porous fiber membrane in the preparation of materials for treating infected wounds.

[0008] The objective of this invention is achieved through the following solution:

[0009] A hybrid phase change porous fiber membrane for enhanced antibacterial properties includes a multi-level porous carbon fiber membrane and a phase change material, tannic acid (TA), and metal nanozymes loaded on the multi-level porous carbon fiber membrane.

[0010] The phase change material is a fatty acid-based phase change material, including at least one of lauric acid, stearic acid, myristic acid, and decanoic acid, preferably lauric acid.

[0011] The metal nanozyme is a peroxidase-like nanozyme, comprising at least one of platinum nanoparticles, gold nanorods, and silver nanoparticles, preferably platinum nanoparticles.

[0012] The multi-level porous carbon fiber membrane is prepared by the following steps:

[0013] (1) Preparation of ZIF-67 nanoparticles: Cobalt salt solution and dimethylimidazole solution were mixed and stirred and co-precipitated to obtain ZIF-67 nanoparticles;

[0014] (2) Preparation of electrospinning solution: ZIF-67 nanoparticles with a particle size of 150 nm were added to a polyacrylonitrile (PAN) solution and stirred thoroughly to disperse them completely and form a uniform and stable mixed spinning solution.

[0015] (3) Electrospinning to prepare precursor composite fiber: Electrospinning was carried out using the polyacrylonitrile / ZIF-67 nanoparticle electrospinning solution obtained in step (2) as raw material to obtain precursor PAN / ZIF-67 composite fiber.

[0016] (4) Preparation of carbon fiber membrane by pre-oxidation and calcination: Multi-level porous carbon fiber membrane is obtained by gradient pre-oxidation and calcination of the precursor composite fiber obtained in step (3).

[0017] The cobalt salt in step (1) is at least one of cobalt nitrate hexahydrate, cobalt acetate, cobalt chloride, and cobalt sulfate, preferably cobalt nitrate hexahydrate; the solvent for the cobalt salt solution and the dimethylimidazole solution is at least one of water and methanol, preferably water.

[0018] The concentration of the cobalt salt solution in step (1) is 0.40-0.45 mol / L, preferably 0.41 mol / L; the concentration of the dimethylimidazole solution is 5-6 mol / L, preferably 5.5 mol / L.

[0019] In step (1), the molar ratio of cobalt ions, dimethylimidazole, and solvent in the solution during mixing and stirring is 1:50-55:650-700, preferably 1:53:680.

[0020] The mixing time in step (1) is 1-4 hours; the mixing speed is 600-1000 rpm.

[0021] The mixing and stirring in step (1) is carried out at a stirring speed of 800 rpm for 2 hours; after the coprecipitation reaction, purification is carried out, specifically by centrifuging the reaction solution at 9000 rpm for 10 minutes, repeating 3 times; and then freeze-drying.

[0022] The solvent for the polyacrylonitrile solution in step (2) is at least one of N,N-dimethylformamide, dichloromethane and hexafluoroisopropanol; preferably N,N-dimethylformamide.

[0023] The weight-average molecular weight of the polyacrylonitrile in step (2) is 10,000-20,000, preferably 15,000.

[0024] The concentration of the polyacrylonitrile solution in step (2) is 8-12 wt%, preferably 10 wt%.

[0025] In step (2), the mass ratio of polyacrylonitrile to ZIF-67 nanoparticles is 100:50 to 70.

[0026] The parameters for electrospinning in step (3) include: an electrostatic field voltage range of 12-20 kV, a spinning receiving distance of 15-25 cm, a syringe advance speed of 0.5-2 mL / h, and a roller rotation speed of 1500-3000 rpm.

[0027] After electrospinning in step (3), the resulting product is dried at a temperature of 40-60℃ for 12-24 hours.

[0028] The gradient pre-oxidation in step (4) specifically involves oxidizing at 180 ℃, 200 ℃, 220 ℃ and 240 ℃ in air atmosphere for 30-60 min, then raising the temperature to 250 ℃ and oxidizing at 250 ℃ for 1-3 h, and finally cooling to room temperature to obtain pre-oxidized composite fibers.

[0029] The calcination in step (4) specifically involves heating the carbon fiber membrane to 800-1000 ℃ at a rate of 5 ℃ / min under an argon atmosphere and calcining it at a constant temperature for 2-6 h to obtain a multi-level porous carbon fiber membrane.

[0030] The above-mentioned method for preparing the hybrid phase change porous fiber membrane with enhanced antibacterial properties includes the following steps: immersing a multi-level porous carbon fiber membrane in a methanol solution containing phase change material, tannic acid, and metal nanozyme at room temperature for 12-36 hours to obtain the hybrid phase change porous fiber membrane with enhanced antibacterial properties.

[0031] The molar ratio of the phase change material, tannic acid, and metal nanozyme is 4500-5000:50-60:1; preferably 4990:58.8:1.

[0032] The mass ratio of the multi-level porous carbon fiber membrane to tannic acid is 0.12-0.250:2, preferably 0.200:2;

[0033] The amount of methanol used satisfies the following condition: the concentration of the phase change material in the resulting solution after mixing is 0.4-0.5 mol / L, preferably 0.49 mol / L.

[0034] After soaking, the hybrid phase change porous fiber membrane is taken out, washed with water three times, and then vacuum dried; wherein the drying temperature is 30-40℃, preferably 37℃; and the drying time is 12-24h, preferably 24h.

[0035] The above-mentioned hybrid phase change porous fiber membrane with enhanced antibacterial properties is used in the preparation of materials for treating infected wounds.

[0036] The specific application involves covering the infected wound with a hybrid phase change porous fiber membrane, then dripping 100 μM hydrogen peroxide solution onto the hybrid phase change porous fiber membrane, and finally irradiating the hybrid phase change porous fiber membrane with a laser.

[0037] Unless otherwise specified, all temperatures in this invention refer to the conditions at room temperature.

[0038] The mechanism of this invention is as follows:

[0039] This invention utilizes ZIF (zeolite-like imidazolium ester framework), a microporous material with a highly customized and well-defined pore structure, as a pore-forming template to composite with polyacrylonitrile (PAN) fibers. Through processes such as pre-oxidation and high-temperature calcination, PAN-based porous carbon fibers can be prepared. The prepared porous carbon nanofibers possess high specific surface area, abundant three-dimensional hierarchical porous structures, excellent photothermal conversion capabilities, and good drug loading and delivery capabilities, making them advantageous for encapsulating and loading phase change materials, nanozymes, and small molecule acids.

[0040] When H2O2 is added and laser irradiation is applied, the PTT antibacterial effect of Pt NPs in the HCF / LA / TA / Pt hybrid phase change porous fiber membrane, the natural antibacterial effect of TA released by LA phase change, the antibacterial effect of Pt NPs themselves, and the antibacterial effect of Pt NPs catalyzing the generation of reactive oxygen species (ROS) from H2O2 by Pt NPs in the weakly acidic environment provided by TA all exhibit a destructive effect on bacterial structure and have high bactericidal activity.

[0041] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0042] 1. This invention uses electrospinning to prepare hybrid phase change porous fiber membranes with enhanced antibacterial properties. The equipment and process are simple, have good repeatability, and can be mass-produced.

[0043] 2. The HCF porous fiber membrane obtained by this invention has a multi-level porous structure and high porosity, and has good encapsulation effect and high loading rate for phase change materials, nanozymes and tannic acid.

[0044] 3. The HCF / LA / TA / Pt hybrid phase change porous fiber membrane obtained by this invention has excellent antibacterial properties and wound healing promotion properties. Attached Figure Description

[0045] Figure 1 The images show scanning electron microscope (SEM) and transmission electron microscope (TEM) images of ZIF-67 nanoparticles of different sizes obtained in Example 1.

[0046] Figure 2 The images show the SEM and TEM images of the precursor composite fiber and its corresponding porous fiber membrane obtained in Example 2.

[0047] Figure 3 This is a schematic diagram of the preparation process of the hybrid phase change porous fiber membrane with enhanced antibacterial properties in the embodiment.

[0048] Figure 4 The N2 adsorption-desorption isotherm and BJH pore size distribution curve of the porous fiber membrane obtained in Example 2 are shown.

[0049] Figure 5 The images show the hybrid phase change porous fiber membrane obtained in Example 3 and its corresponding SEM and TEM images.

[0050] Figure 6 This describes the application of the hybrid phase change porous fiber membrane obtained in Example 3 in antibacterial applications.

[0051] Figure 7 This describes the application of the hybrid phase change porous fiber membrane obtained in Example 3 in the treatment of bacterial infection wounds. Detailed Implementation

[0052] The present invention will be further described in detail below with reference to embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0053] Unless otherwise specified, all reagents used in the examples are commercially available.

[0054] Example 1: Preparation of ZIF-67 nanoparticles

[0055] First, three 1.2 g portions of cobalt nitrate hexahydrate were weighed and dissolved in 10, 20, and 25 mL of deionized water, respectively. Then, three 18 g portions of 2-methylimidazole were weighed and dissolved in 40, 80, and 100 mL of deionized water, respectively, by ultrasonication. The two solutions were then mixed and stirred at 800 rpm for 2 h. After centrifugation at 9000 rpm for 10 min, the mixture was washed three times and then freeze-dried at low temperature to obtain ZIF-67 nanoparticles.

[0056] A small amount of ZIF-67 nanoparticle powder was adhered to a conductive adhesive, and a scanning electron microscope image of ZIF-67 was obtained as shown below. Figure 1 As shown in the figure, a, d; b, e; c, f are SEM images and particle size distribution histograms of ZIF-67 nanoparticles with diameters of 150, 300, and 400 nm, respectively. It can be seen from the figure that the three different sizes of ZIF-67 nanoparticles all have a rhombic dodecahedral structure and are uniformly distributed. The particle sizes of ZIF-67 nanoparticles were measured to be 150, 300, and 400 nm by particle size statistics using ImageJ software.

[0057] A small amount of ZIF-67 ethanol solution was taken, ultrasonically dispersed, and then a small amount of the solution was dropped onto a copper mesh to prepare a transmission electron microscope (TEM) sample. The TEM image of the ZIF-67 nanoparticles is shown below. Figure 1 As shown, g, h, and i are TEM images of ZIF-67 nanoparticles with particle sizes of 150, 300, and 400 nm, respectively. The ZIF-67 nanoparticles have a uniform morphology and exhibit a hexagonal structure. The particle size is roughly consistent with the SEM results.

[0058] Example 2: Preparation of PAN / ZIF-67 precursor composite fibers with different doping amounts and particle sizes and porous carbon fibers obtained by calcination

[0059] 1g of PAN powder (weight average molecular weight of 15000) was dissolved in 9g of N,N-dimethylformamide and stirred until completely dissolved to obtain a 10wt% PAN spinning solution. 30, 50, and 70wt% of 150nm ZIF-67 nanoparticles and 70wt% of 300 and 400nm ZIF-67 nanoparticles were then added to the solution to obtain five mixed spinning solutions (where "30, 50, and 70wt%" refers to the ratio of the mass of ZIF-67 nanoparticles to the mass of PAN). After thoroughly stirring each mixed spinning solution, electrospinning was performed at a voltage of 15 kV, a receiving distance of 20 cm, a feed rate of 1 mL / h, and a roller speed of 2000 rpm. Five sets of precursor composite fibers, namely PAN / 30%ZIF-67 (150 nm), PAN / 50%ZIF-67 (150 nm), PAN / 70%ZIF-67 (150 nm), PAN / 70%ZIF-67 (300 nm), and PAN / 70%ZIF-67 (400 nm), were prepared and dried in a drying oven at 60 ℃ for 12 h for later use.

[0060] Five sets of precursor composite fibers were placed in an electrically heated drying oven for gradient pre-oxidation. Oxidation was carried out at 180 ℃, 200 ℃, 220 ℃, and 240 ℃ sequentially for 0.5 h in air, followed by a further increase to 250 ℃ and a 1 h oxidation at the same temperature. The fibers were then slowly cooled to room temperature to obtain pre-oxidized composite fibers. These pre-oxidized composite fibers were folded and placed in a crucible in a tube furnace for carbonization. The furnace was then heated to 800 ℃ at a rate of 5 ℃ / min and calcined at the same temperature for 3 h in an argon atmosphere to prepare five sets of porous carbon fibers: HCF-30% (150 nm), HCF-50% (150 nm), HCF-70% (150 nm), HCF-70% (300 nm), and HCF-70% (400 nm).

[0061] Five sets of precursor composite fibers and their corresponding porous carbon fibers were cut into small pieces and glued onto conductive adhesive. After gold sputtering, scanning electron microscope (SEM) images of the five sets of precursor composite fibers and their corresponding porous carbon fibers were obtained. Several fibers from the five sets of porous carbon fibers were placed in double copper mesh to prepare transmission electron microscope (TEM) samples. The TEM images are shown below. Figure 2 As shown.

[0062] Figure 2ab; ef; ij; mn; qr are SEM images of PAN / 30%ZIF-67 (150 nm), PAN / 50%ZIF-67 (150 nm), PAN / 70%ZIF-67 (150 nm), PAN / 70%ZIF-67 (300 nm), and PAN / 70%ZIF-67 (400 nm), respectively. The results show that the fiber morphology is uniform and the arrangement is oriented. With the increase of doping concentration, the original composite fiber ( Figure 2 The number of particles on the surfaces of (a), (e), and (i) increased, but the distribution of ZIF-67 nanoparticles in the fiber was relatively uniform, with no obvious agglomeration. Figure 2 In the figure, i, m, and q represent the comparison of ZIF-67 nanoparticle composite fibers with different particle sizes. SEM results show that as the particle size increases, the distribution of ZIF-67 nanoparticles in the fiber becomes uneven, and obvious agglomeration occurs.

[0063] Figure 2 cd, gh, kl, op, and st are SEM and TEM images of HCF-30% (150 nm), HCF-50% (150 nm), HCF-70% (150 nm), HCF-70% (300 nm), and HCF-70% (400 nm), respectively. The images show that the carbon fibers after calcination (…) Figure 2 The surface porosity of (c, g, k) nanoparticles also increased with increasing doping concentration of ZIF-67 nanoparticles. TEM results ( Figure 2 The TEM results (d, h, l) also indicate that the higher the doping concentration, the more pores are inside the fiber, forming a three-dimensional interconnected network structure. Figure 2 The values ​​of l, p, and t also indicate that the internal pores of carbon fibers with large doped particle sizes are unevenly distributed, and that the pores in HCF-70% (400 nm) fibers are mostly isolated from each other and do not communicate with each other.

[0064] The specific reaction routes for Examples 2 and 3 are as follows: Figure 3 As shown

[0065] The differences in the internal porous structure of the five groups of porous carbon fibers prepared in Example 2 were studied by N2 adsorption and desorption tests. An appropriate amount of porous carbon fibers was loaded into a pre-weighed sample tube and placed in a degassing station for heating and vacuum degassing to remove the air and water vapor adsorbed on the sample itself. The dry weight of the fiber sample was weighed and calculated. The sample tube was then placed in the analysis station and a filling rod was inserted for nitrogen adsorption and desorption tests.

[0066] The adsorption-desorption isotherms calculated using the BET model are as follows: Figure 4As shown in Figure a, all five sets of curves exhibit hysteresis loops, belonging to type IV isotherms. Among them, HCF-50% (150 nm) and HCF-70% (150 nm) belong to type H2 hysteresis loops, with saturated adsorption plateaus, which are commonly found in some three-dimensional mesoporous (2-50 nm) materials. HCF-70% (300 nm) and HCF-70% (400 nm) belong to type H3 hysteresis loops, while HCF-30% (150 nm) belongs to type H4 hysteresis loops. None of them have obvious saturated adsorption plateaus, indicating that their pore structures are irregular.

[0067] The carbon fiber pore size distribution curve calculated using the BJH method is shown below. Figure 4 As shown in Figure b, the results are consistent with those calculated by the BET model. The internal pores of the HCF-50% (150 nm) and HCF-70% (150 nm) fibers are mainly mesoporous (2-50 nm) multi-level porous structures, while the other three groups have no obvious peaks within the pore size of 100 nm and are irregular macroporous (>50 nm) structures.

[0068] Example 3: Preparation of HCF / LA / TA / Pt hybrid phase change porous fiber membrane

[0069] Hybrid phase change porous fiber membranes were prepared by impregnating porous carbon fibers with lauric acid, tannic acid, and platinum nanoparticles. First, 20 g of LA powder, 2 g of TA powder, and 4 mg of Pt NPs were placed in a 500 mL beaker, and 200 mL of methanol was added to dissolve them thoroughly, obtaining a mixed solution. Next, 200 mg of HCF-70% (150 nm) porous fibers were weighed and immersed in the above mixed solution, then placed on a shaker and immersed for 24 h. After immersion, the hybrid phase change porous fibers were washed three times with deionized water and dried in a vacuum oven at 37 ℃ for 24 h to obtain the HCF / LA / TA / Pt hybrid phase change porous fiber membrane.

[0070] HCF / LA, HCF / LA / TA, and HCF / LA / Pt were prepared using the same method. HCF / LA consisted of 200 mg HCF-70% (150 nm) loaded with 20 g of LA powder; HCF / LA / TA consisted of 200 mg HCF-70% (150 nm) loaded with 20 g of LA powder and 2 g of TA powder; and HCF / LA / Pt consisted of 200 mg HCF-70% (150 nm) loaded with 20 g of LA powder and 4 mg of PtNPs.

[0071] Hybrid phase change porous fiber membranes with different compositions were cut into small pieces and adhered to conductive adhesive. After gold sputtering, scanning electron microscope (SEM) images of each group of porous fiber membranes were obtained. Several fibers from different hybrid phase change porous fiber membranes were placed in double copper mesh to prepare transmission electron microscope (TEM) samples. TEM images are shown below. Figure 5 As shown.

[0072] Figure 5 SEM and TEM images of four hybrid phase change porous fibers, namely HCF / LA, HCF / LA / TA, HCF / LA / Pt, and HCF / LA / TA / Pt, are shown. The results indicate that the fibers retain a certain orientation structure, compared with... Figure 2 The pores on the surface of the original porous carbon fiber HCF-70% (150 nm) were filled after loading their respective components. Nodular protrusions could be seen on the fiber surface. These were the loadings of LA, which was the main component adsorbed by the fiber pores. The loading contents of TA and Pt NPs were relatively low. Therefore, the three groups of fibers loaded with these two components did not show significant differences from the HCF / LA composite fiber in the SEM images.

[0073] The results of TEM were consistent with those of SEM, compared to Figure 2 The TEM image of the original porous carbon fiber HCF-70% (150 nm) clearly shows that the pores inside the fiber are filled with the loading material. In contrast, the TEM images of the two sets of composite fibers with Pt NPs show small black dots with higher contrast than the surrounding area. These are Pt NPs loaded inside the fiber. The TEM images also show that the loading amount of Pt NPs in the fiber is small and the distribution is sparse.

[0074] Application Example 1: Antibacterial effect of HCF / LA / TA / Pt hybrid phase change porous fiber membrane on Escherichia coli and Staphylococcus aureus

[0075] (1) Preparation of bacterial suspension: *Escherichia coli* (ATCC25922) and *Staphylococcus aureus* (ATCC6538) were inoculated separately onto LB liquid medium (Beijing Coollab Technology Co., Ltd.) and incubated at 37 ℃ for 6-9 h. The bacterial suspension was then inoculated onto LB solid medium (purchased from Beijing Coollab Technology Co., Ltd.) using the streak plate method and incubated upside down at 37 ℃ for 18-24 h. Single colonies were picked and incubated upside down at 37 ℃ and 100 rpm for 6-9 h to prepare 1.0 × 10⁻⁶ liters of LB liquid medium. 5 CFU / mL bacterial suspension.

[0076] (2) Take 1.5 mg of hybrid phase change composite fibers with different components (HCF / LA group, HCF / LA / TA group, HCF / LA / Pt group and HCF / LA / TA / Pt group) and mix them with 1.5 mL of bacterial solution (1×10⁻⁶).5 The bacterial culture was co-incubated with H2O2 (CFU / mL) for 12 h. Four control experiments were conducted under different conditions (None, H2O2, Laser, and H2O2+Laser, with H2O2 concentration of 100 μM, Laser being a 1064 nm near-infrared laser, and Laser irradiation time of 10 min) based on the presence or absence of H2O2 and laser irradiation. The bacterial culture after 12 h of co-cultivation was diluted 10... 4 After doubling (~1000 CFU / mL), take 50 μL and drop it onto LB solid medium, spread it evenly, and incubate at 37℃ and 100 rpm for 24 h. Then, remove the plate, photograph it, and count the results. Figure 6 As shown.

[0077] For comparison, a control group was set up, which was a blank control group containing only bacterial culture and no other treatments, i.e., directly adding 1.5 mL of 1.0×10⁻⁶ bacterial culture. 5 The bacterial suspension was cultured at CFU / mL.

[0078] from Figure 6 As can be seen, there was no significant difference in the colony counts of *E. coli* and *Staphylococcus aureus* in the control group under four different conditions. The antibacterial effect of the control fiber did not change significantly after the addition of H2O2, indicating that the 100 μM H2O2 itself had no significant killing effect on either bacterium. After 10 minutes of laser irradiation, the colony count of the HCF / LA composite fiber decreased. The HCF / LA / TA composite fiber released more TA due to the photothermal effect, resulting in enhanced antibacterial effect and a further reduction in colony count. The HCF / LA / TA / Pt composite fiber achieved its optimal antibacterial effect after the addition of H2O2 and laser irradiation, with no colonies appearing. The high antibacterial activity of the HCF / LA / TA / Pt hybrid phase change porous fiber is attributed to the photothermal antibacterial effect of Pt NPs, the natural antibacterial effect of TA released from the LA phase change, and the antibacterial effect of Pt NPs catalyzing the generation of ROS from H2O2 in the weakly acidic environment provided by TA.

[0079] Application Example 2: The wound-healing effect of HCF / LA / TA / Pt hybrid phase change porous fiber membrane on Staphylococcus aureus infected wounds

[0080] This experiment used Staphylococcus aureus (Staphylococcus aureus) S.aureusThe performance of HCF / LA / TA / Pt hybrid phase change composite fibers in promoting wound healing was evaluated using a rat model of full-thickness dermal wound defect (ATCC 6538) infection. SD rats (250-300g, 8 weeks old) were used in the experiment, and all animal experiments were approved by the Animal Research Committee of South China Agricultural University. All rats were randomly divided into five groups according to different experimental conditions: control group (treated with commercial dressing Tegaderm film (3M Healthcare, USA)), HCF / LA / TA / Pt group, HCF / LA / TA / Pt + H2O2 group, HCF / LA / TA / Pt + Laser group, and HCF / LA / TA / Pt + H2O2 + Laser group. The H2O2 concentration was 100 μM; groups without H2O2 used an equal volume of PBS instead. The Laser was a 1064 nm near-infrared laser, and the Laser irradiation time was 10 min. Three rats were in each group. After anesthetizing the rats, a circular wound with a diameter of 15 mm was cut on their backs, and... S.aureus Bacterial suspension infection was recorded as day 1. Wound dressings were changed and laser irradiation was performed on days 1, 3, 5, and 7. Wound healing status of rats in each group was recorded by photograph every other day.

[0081] from Figure 7 As can be seen, on day 3, the wound healing effect of the HCF / LA / TA / Pt + H2O2 + Laser treatment group was significantly better than that of the other four groups. On day 7, the wound area of ​​the HCF / LA / TA / Pt + H2O2, HCF / LA / TA / Pt + Laser, and HCF / LA / TA / Pt + H2O2 + Laser treatment groups all decreased significantly, with the HCF / LA / TA / Pt + H2O2 + Laser treatment group showing the best healing effect. By day 14, the wound in the HCF / LA / TA / Pt + H2O2 + Laser treatment group had basically healed. Therefore, under H2O2 and laser irradiation, the HCF / LA / TA / Pt hybrid phase change porous fiber membrane has good wound healing promotion properties.

[0082] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A hybrid phase change porous fiber membrane with enhanced antibacterial properties, characterized in that: The invention includes a multi-level porous carbon fiber membrane and a phase change material, tannic acid, and metal nanozymes supported on the multi-level porous carbon fiber membrane; the metal nanozymes are platinum nanoparticles. The multi-level porous carbon fiber membrane is prepared by the following steps: (1) Preparation of ZIF-67 nanoparticles: Cobalt salt solution and dimethylimidazole solution were mixed and stirred and co-precipitated to obtain ZIF-67 nanoparticles; (2) Preparation of electrospinning solution: ZIF-67 nanoparticles with a particle size of 150 nm are added to a polyacrylonitrile solution and stirred thoroughly to disperse them completely and form a uniform and stable mixed spinning solution; the mass ratio of polyacrylonitrile to ZIF-67 nanoparticles is 100:50~70. (3) Electrospinning to prepare precursor composite fiber: Electrospinning was carried out using the polyacrylonitrile / ZIF-67 nanoparticle electrospinning solution obtained in step (2) as raw material to obtain precursor PAN / ZIF-67 composite fiber. (4) Preparation of carbon fiber membrane by pre-oxidation and calcination: The precursor composite fiber obtained in step (3) is subjected to gradient pre-oxidation and calcination to obtain a multi-level porous carbon fiber membrane; the gradient pre-oxidation specifically involves isolating the fiber at 180 ℃, 200 ℃, 220 ℃ and 240 ℃ in air atmosphere for 30-60 min, then raising the temperature to 250 ℃ and isolating it at 250 ℃ for 1-3 h, and then cooling it to room temperature to obtain the pre-oxidized composite fiber; The preparation of the enhanced antibacterial hybrid phase change porous fiber membrane includes the following steps: immersing a multi-level porous carbon fiber membrane in a methanol solution containing phase change material, tannic acid, and metal nanozyme at room temperature for 12-36 hours to obtain the enhanced antibacterial hybrid phase change porous fiber membrane. The molar ratio of the phase change material, tannic acid, and metal nanozyme is 4500-5000:50-60:

1.

2. The hybrid phase change porous fiber membrane with enhanced antibacterial properties according to claim 1, characterized in that: The phase change material is a fatty acid-based phase change material, including at least one of lauric acid, stearic acid, myristic acid, and decanoic acid.

3. The hybrid phase change porous fiber membrane with enhanced antibacterial properties according to claim 1, characterized in that: The cobalt salt mentioned in step (1) is at least one of cobalt nitrate hexahydrate, cobalt acetate, cobalt chloride, and cobalt sulfate; the solvent for the cobalt salt solution and the dimethylimidazole solution is at least one of water and methanol; The concentration of the cobalt salt solution in step (1) is 0.40-0.45 mol / L; the concentration of the dimethylimidazole solution is 5-6 mol / L; In step (1), the molar ratio of cobalt ions, dimethylimidazole, and solvent in the solution during mixing and stirring is 1:50-55:650-700. The mixing time in step (1) is 1-4 hours; the mixing speed is 600-1000 rpm.

4. The hybrid phase change porous fiber membrane with enhanced antibacterial properties according to claim 1, characterized in that: The solvent for the polyacrylonitrile solution in step (2) is at least one of N,N-dimethylformamide, dichloromethane, and hexafluoroisopropanol; The weight-average molecular weight of the polyacrylonitrile mentioned in step (2) is 10,000-20,000; The concentration of the polyacrylonitrile solution in step (2) is 8-12 wt%.

5. The hybrid phase change porous fiber membrane with enhanced antibacterial properties according to claim 1, characterized in that: The parameters for electrospinning in step (3) include: electrostatic field voltage range of 12-20 kV, spinning receiving distance of 15-25 cm, syringe push speed of 0.5-2 mL / h, and roller rotation speed of 1500-3000 rpm; The calcination in step (4) specifically involves heating the carbon fiber membrane to 800-1000 ℃ at a rate of 5 ℃ / min under an argon atmosphere and calcining it at a constant temperature for 2-6 h to obtain a multi-level porous carbon fiber membrane.

6. The hybrid phase change porous fiber membrane with enhanced antibacterial properties according to claim 1, characterized in that: The mass ratio of the multi-level porous carbon fiber membrane to tannic acid is 0.12-0.250:2; The amount of methanol used is such that the concentration of the phase change material in the resulting solution after mixing is 0.4-0.5 mol / L.

Images