Photoelectric responsive antibacterial nanofiber membranes, their preparation methods and applications

Abstract

This invention discloses a photoresponse antibacterial nanofiber membrane, its preparation method, and its application. Polymethylene blue (PMB) is stably loaded onto hypercrosslinked polymer nanospheres, and a composite nanofiber film material with uniformly dispersed PMB is prepared by in-situ electrospinning and electrospraying. This allows for the long-term and efficient release of the photoresponse antibacterial activity of PMB on a flexible substrate. The preparation method includes preparing hypercrosslinked polymer nanospheres; adsorbing PMB onto the hypercrosslinked polymer nanospheres and in-situ polymerization of PMB to obtain PMB-loaded hypercrosslinked polymer nanospheres (HCPs-PMB); preparing a polymer solution as a spinning solution, and mixing HCPs-PMB with the polymer solution as an electrospraying solution; electrospinning the spinning solution to form a nanofiber substrate membrane, and then rapidly switching the electrospraying solution in situ to perform electrospraying on the nanofiber substrate membrane to obtain the photoresponse antibacterial nanofiber membrane.

Description

Technical Field

[0001] This invention relates to the field of functional nanofiber membrane technology, and more specifically to a photoelectric responsive antibacterial nanofiber membrane, its preparation method and application. Background Technology

[0002] Methylene blue (MB), a classic phenothiazine cationic dye, not only possesses excellent antibacterial properties but also exhibits photodynamic antibacterial effects by generating reactive oxygen species (ROS) under light conditions. Furthermore, its reversible redox properties make it a potential material for electrochemical responses. In recent years, with the development of photoelectrochemically responsive antibacterial materials, methylene blue, due to its dual response capabilities of photoactivation and electromodulation, has been considered one of the ideal candidate molecules for constructing intelligent antibacterial systems.

[0003] However, despite the excellent photodynamic and electrochemical activity of methylene blue in solution, it still faces two major challenges in practical applications. First, methylene blue molecules are prone to photobleaching and structural degradation under light irradiation, leading to a rapid decline in its photosensitivity and difficulty in maintaining a long-lasting antibacterial effect. This photoinstability severely limits its application potential in antibacterial materials requiring long-term or repeated use. Second, current supports for loading methylene blue are generally mesoporous materials. However, small MB molecules are not easily loaded in large quantities in traditional mesoporous structures, and there is a lack of functional matrix materials that can efficiently load and disperse methylene blue, resulting in limited and uneven MB loading. Under the influence of high-concentration MB agglomeration, the ROS yield decreases. Traditional physical adsorption or simple blending methods often lead to easy molecule detachment and uneven distribution, and release is difficult to control under humidification or mechanical stress. In addition, most support materials cannot synergistically exert the photoelectric response antibacterial function of methylene blue, nor can they effectively protect it from photodegradation, resulting in limited antibacterial performance and low response efficiency.

[0004] Nanofiber membranes are considered highly promising bio-dressings due to their high specific surface area, tunable pore structure, good flexibility, and matrix compatibility. If a methylene blue-based photoelectric responsive antibacterial nanofiber membrane can be constructed through innovation in material design and fabrication processes, it is hoped that current bottlenecks can be overcome, achieving efficient, long-lasting, and tunable antibacterial functions. Summary of the Invention

[0005] Due to the aforementioned deficiencies in existing technologies, this invention provides a photoelectric responsive antibacterial nanofiber membrane, its preparation method, and its application. Polymethylene blue is stably loaded onto hypercrosslinked polymer (HCP) nanospheres, and a composite nanofiber thin film material with uniformly dispersed polymethylene blue is prepared by in-situ electrospinning and electrospraying. This allows the photoelectric responsive antibacterial activity of polymethylene blue to be released efficiently and for a long time on a flexible substrate, thereby solving the bottleneck problem faced by the practical application of methylene blue.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a method for preparing a photoelectric responsive antibacterial nanofiber membrane, comprising the following steps:

[0007] Step S1: Obtain hypercrosslinked polymer nanospheres through polymerization reaction; prepare a polymer solution with electrospinning properties as a spinning solution;

[0008] Step S2: Mix the supercrosslinked polymer nanospheres with a methylene blue aqueous solution and stir thoroughly at room temperature in the dark until the supercrosslinked polymer nanospheres adsorb methylene blue to reach equilibrium.

[0009] Step S3: Add ammonium persulfate solution to the solution in step S2 and stir thoroughly. After filtration, wash and dry to obtain supercrosslinked polymer nanospheres loaded with polymethylene blue.

[0010] Step S4: Mix the polymer solution from step S1 with the supercrosslinked polymer nanospheres loaded with polymethylene blue to obtain an electrospray solution;

[0011] Step S5: Electrospinning is performed using the spinning solution obtained in step S1 to form a nanofiber base film. Then, the electrospray solution is quickly switched in situ to perform electrospraying on the nanofiber base film to obtain a photoelectric responsive antibacterial nanofiber film.

[0012] The above technical solution uses hypercrosslinked polymer nanospheres as a carrier for polymethylene blue. After polymerization, the polymethylene blue is stably loaded inside and on the surface of the hypercrosslinked polymer nanospheres. At the same time, the in-situ electrospraying technology after electrospinning allows the polymethylene blue-loaded hypercrosslinked polymer nanospheres to be uniformly loaded onto the polymer nanofiber membrane, thereby forming a flexible composite nanofiber membrane with stable and continuous photoelectric response antibacterial properties.

[0013] In some embodiments, in step S5, electrospinning and electrospraying are performed alternately several times to obtain a multilayer composite photoelectric responsive antibacterial nanofiber membrane, thereby allowing the membrane component ratio to be adjusted according to the needs of the application scenario.

[0014] In some embodiments, the polymer in step S1 is one or more of polycaprolactone, gelatin, polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, polylactic acid, and carboxymethyl cellulose, which can be selected according to the hydrophilicity and hydrophobicity requirements of the application environment.

[0015] In some embodiments, the hypercrosslinked polymer nanospheres are obtained by catalytic polymerization of aromatic hydrocarbon monomers. The preparation process includes: dissolving the aromatic hydrocarbon monomers in dichloroethane and heating them; adding the catalyst FeCl3 under an inert atmosphere and stirring to induce a Friedel-Crafts crosslinking reaction; filtering, washing and drying after the reaction to obtain the hypercrosslinked polymer nanospheres.

[0016] In some embodiments, the aromatic hydrocarbon monomer is one of terephthalic acid, 1-naphthaleneethanol, 9-anthraciteethanol, and 1-pyreneethanol, and the concentration of the aromatic hydrocarbon monomer is 0.05 mol / L; the aromatic hydrocarbon monomer is dissolved in dichloroethane and heated to 80°C; the molar ratio of the aromatic hydrocarbon monomer to FeCl3 is 1:2.

[0017] In some embodiments, in step S2, the concentration of methylene blue in the aqueous solution is 2-9 w / v%. Example methylene blue concentrations are 2 w / v%, 3 w / v%, 4 w / v%, 5 w / v%, 6 w / v%, 7 w / v%, 8 w / v%, or 9 w / v.

[0018] In some embodiments, in step S4, the mass-to-volume ratio of the supercrosslinked polymer nanospheres loaded with polymethylene blue to the polymer solution is 1:100.

[0019] Secondly, the present invention provides a photoelectric responsive antibacterial nanofiber membrane, which is prepared by the photoelectric responsive antibacterial nanofiber membrane preparation method described above;

[0020] Nanofibers interweave to form a thin film framework; nanoparticles are loaded on the surface and between the nanofibers.

[0021] The nanofibers and nanoparticles are firmly linked by the same polymer.

[0022] The nanoparticles contain photo-responsive antibacterial functional materials; the photo-responsive antibacterial functional materials include hypercrosslinked polymer nanospheres loaded with polymethylene blue.

[0023] In some embodiments, the nanofibers are composed of one or more of polycaprolactone, gelatin, polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, polylactic acid, and carboxymethyl cellulose; the hypercrosslinked polymer nanospheres are obtained by catalytic polymerization of aromatic hydrocarbon monomers; the aromatic hydrocarbon monomers are one of terephthalic acid, 1-naphthalimethanol, 9-anthraphthalimethanol, and 1-pyreneethanol.

[0024] Finally, the present invention provides an application of a photoresponse antibacterial nanofiber membrane as a biological antibacterial dressing, wherein the photoresponse antibacterial nanofiber membrane is as described above.

[0025] The above technical solution is only one feasible technical solution of the present invention. The scope of protection of the present invention is not limited thereto. Those skilled in the art can reasonably adjust the specific design according to actual needs.

[0026] The above invention has the following advantages or beneficial effects:

[0027] (1) This invention obtains super-crosslinked polymer nanospheres loaded with polymethylene blue through in-situ polymerization of methylene blue, and then obtains a nanofiber membrane with uniformly dispersed PMB by co-spinning with a polymer matrix. The rigid microporous structure of HCP in this membrane has a confinement effect on the PMB chain segments, effectively preventing the π-π accumulation of photosensitive groups and overcoming the technical problem of decreased ROS yield under high MB concentration, thus serving as a novel effective carrier for methylene blue. At the same time, HCP efficiently loads and disperses PMB, and the resulting photo-responsive antibacterial composite functional material can effectively avoid the photodegradation of MB, ensuring the long-term controllable release of the photo-responsive antibacterial activity of methylene blue. Compared with MB monomers, PMB forms a stable polymer network through polymerization, which can be well loaded in the microporous structure, solving the problem that small MB molecules are not easy to load in traditional mesoporous structures. This is crucial for destroying the dense bacterial biofilm. At the same time, PMB further improves the charge transport capacity of the nanofiber membrane compared with MB, which helps to promote electron-hole separation and migration efficiency under light conditions, enhances the ROS generation capacity, and thus improves the photodynamic antibacterial performance of the membrane material.

[0028] (2) In this invention, the antibacterial nanoparticles are uniformly dispersed on the nanofiber base film during in-situ electrospraying and are firmly connected to the nanofiber base film through the same polymer, which further solves the problem of stable dispersion of antibacterial active molecule PMB, thereby further improving the photoelectric response antibacterial performance of the nanofiber film.

[0029] (3) The HCP nanospheres in this invention can be easily obtained in one step. The process is simple, does not require complex conditions or expensive catalysts, does not produce toxic byproducts, and is environmentally friendly. It adopts relatively mature electrospinning and electrospraying technologies and has high practical application value. Attached Figure Description

[0030] The invention, its features and advantages will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0031] Figure 1 This is a SEM image of the hypercrosslinked polymer nanospheres HCPs-PMB loaded with polymethylene blue obtained in Example 1 of this invention.

[0032] Figure 2 This is a SEM image of the nanofiber-based membrane prepared in Example 1 of the present invention.

[0033] Figure 3 This is a SEM image of the photoelectric responsive antibacterial fiber membrane PMB@HCP-P / G prepared in Example 1 of the present invention.

[0034] Figure 4The image shows the antibacterial effect of the photoelectric responsive antibacterial fiber membranes in Embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention against Escherichia coli (E-coli).

[0035] Figure 5 The image shows the antibacterial effect of the photoelectric responsive antibacterial fiber membranes in Examples 1, 1, and 2 of this invention against Staphylococcus aureus.

[0036] Figure 6 The ROS generation rate curves of the photoelectric responsive antibacterial fiber membranes in Examples 1, 1, and 2 of this invention under photodynamic therapy are shown.

[0037] Figure 7 The conductivity diagrams are for the photoelectric responsive antibacterial fiber membranes in Examples 1, 3, and Comparative Examples 1 to 3 of the present invention. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0039] The reaction apparatus, monomer compounds, and solvents involved in the following examples and embodiments are all commercially available. The detection instruments involved in the following effect examples are all commercially available, and the detection methods used are existing technologies that can be found; and the technologies not described in detail in the following effect examples are existing technologies that can be found.

[0040] First, this invention provides a method for preparing a photoelectric responsive antibacterial nanofiber membrane, comprising the following steps:

[0041] Step S1: Obtain hypercrosslinked polymer nanospheres through polymerization reaction; prepare a polymer solution with electrospinning properties as a spinning solution;

[0042] Step S2: Mix the supercrosslinked polymer nanospheres with a methylene blue aqueous solution and stir thoroughly at room temperature in the dark until the supercrosslinked polymer nanospheres adsorb methylene blue to reach equilibrium.

[0043] Step S3: Add ammonium persulfate solution to the solution in step S2 and stir thoroughly. After filtration, wash and dry to obtain supercrosslinked polymer nanospheres loaded with polymethylene blue.

[0044] Step S4: Mix the polymer solution from step S1 with the supercrosslinked polymer nanospheres loaded with polymethylene blue to obtain an electrospray solution;

[0045] Step S5: Electrospinning is performed using the spinning solution obtained in step S1 to form a nanofiber base film. Then, the electrospray solution is quickly switched in situ to perform electrospraying on the nanofiber base film to obtain a photoelectric responsive antibacterial nanofiber film.

[0046] The prepared photoresponse nanofiber membrane has nanofibers interwoven to form a thin film framework; nanoparticles are loaded on the surface and gaps of the nanofibers; the nanofibers and nanoparticles are firmly connected by the same polymer; the nanoparticles contain photoresponse antibacterial functional materials; the photoresponse antibacterial functional materials include hypercrosslinked polymer nanospheres loaded with polymethylene blue.

[0047] This invention utilizes in-situ polymerization of methylene blue to obtain hypercrosslinked polymeric nanospheres loaded with polymeric methylene blue, which are then co-spun with a polymer matrix to obtain a nanofiber membrane with uniformly dispersed PMB. The rigid microporous structure of the HCP in this membrane creates a confinement effect on the PMB segments, effectively preventing the π-π aggregation of photosensitive groups and overcoming the technical challenge of decreased ROS yield at high MB concentrations. Simultaneously, the efficient loading and dispersion of PMB by HCP results in a photoresponse antibacterial composite material that effectively prevents the photodegradation of MB, ensuring the long-term, controllable release of the photoresponse antibacterial activity of methylene blue.

[0048] As an example, the polymer substrate is one or more of polycaprolactone, gelatin, polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, polylactic acid, and carboxymethyl cellulose, which can be selected according to the hydrophilicity / hydrophobicity requirements of the application environment. If the application scenario is outer layer protection, hydrophobic materials such as polycaprolactone and polylactic acid are preferred. If the application scenario is accelerated healing and bioactivity, hydrophilic materials such as gelatin, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, and carboxymethyl cellulose are preferred.

[0049] The preferred preparation process of hypercrosslinked polymer nanospheres is as follows: Aromatic hydrocarbon monomers are dissolved in dichloroethane and heated. Under an inert atmosphere, FeCl3 catalyst is added and stirred to induce a Friedel-Crafts crosslinking reaction. After the reaction, the mixture is filtered, washed, and dried to obtain hypercrosslinked polymer nanospheres. The aromatic hydrocarbon monomer is one of terephthalic acid, 1-naphthaleneethanol, 9-anthraceneethanol, or 1-pyreneethanol, selected based on the strength of π-π conjugation interactions. In this invention, HCP nanospheres can be easily obtained in one step, with a simple process, requiring no complex conditions or expensive catalysts, and producing no toxic byproducts, making it environmentally friendly.

[0050] The technical solution of the present invention will now be described in detail with reference to specific embodiments and comparative examples.

[0051] Example 1

[0052] The preparation method of the photoelectric responsive antibacterial fiber membrane in this embodiment is as follows:

[0053] (1) Dissolve terephthalic acid in dichloroethane solution at a concentration of 0.05 mol / L and heat to 80℃. Add FeCl3 catalyst under N2 protection and stir to induce Friedel-Crafts crosslinking reaction. The molar ratio of terephthalic acid to FeCl3 is 1:2, the rotation speed is 350 r / min, and the reaction time is 24 h.

[0054] (2) After the reaction is complete, filter the turbid product with filter paper. Use anhydrous ethanol for initial rinsing during filtration. Then place the product in a Soxhlet extractor for washing. Place the washed product in a drying oven for drying to ensure the removal of the catalyst and obtain HCP nanospheres. Mix the HCP nanospheres with a 2% w / v methylene blue aqueous solution to allow HCP to adsorb methylene blue. Then add ammonium persulfate solution and stir to carry out the polymerization reaction of methylene blue, and finally obtain HCP nanospheres HCPs-PMB loaded with polymethylene blue.

[0055] (3) Add 0.5 g of the polymer matrix gelatin-polycaprolactone (GEL-PCL) to 10 mL of water and stir to prepare a spinning solution; add the super-crosslinked polymer nanospheres loaded with polymethylene blue to the electrospinning solution and mix evenly to obtain an electrospray solution; the mass-volume ratio of the super-crosslinked polymer nanospheres loaded with polymethylene blue to the electrospinning solution is 1:100.

[0056] (4) Electrospinning was performed using a spinning solution. The electrospinning voltage was 8 kV and the flow rate was 0.25 mL / h. The nanofiber base membrane was obtained by receiving it on a roller receiver. Before the nanofiber base membrane was dried, the spinning head was replaced with an electrospray head, and an electrospray solution was used to perform in-situ electrospraying on the nanofiber base membrane. After drying, the photoelectric responsive antibacterial nanofiber membrane PMB@HCPs-P / G was obtained.

[0057] Example 2

[0058] The preparation method of the photoelectric responsive antibacterial fiber membrane provided in this embodiment is similar to that in Example 1, except that electrospinning and electrospraying are performed alternately several times to obtain a multilayer composite photoelectric responsive antibacterial nanofiber membrane.

[0059] Example 3

[0060] The preparation method of the photoelectric responsive antibacterial fiber membrane provided in this embodiment is similar to that in Example 1, except that in step (2), the concentration of the methylene blue aqueous solution is 5% w / v.

[0061] Example 4

[0062] The preparation method of the photoelectric responsive antibacterial fiber membrane provided in this embodiment is similar to that in Example 2, except that in step (2), the concentration of the methylene blue aqueous solution is 9% w / v.

[0063] See Figure 1 The hypercrosslinked polymer nanospheres HCPs-PMB loaded with polymethylene blue are spherical with a diameter of approximately 250 nm. The surface of these spheres is rough and rich in micropores. (See also...) Figure 2 and Figure 3 In Example 1, the electrospun PMB@HCPs-P / G was composed of interwoven nanofibers with a diameter of approximately 1.5 μm, exhibiting a smooth fiber surface and abundant pores. The nanofiber membrane obtained in Example 2 possessed a multilayered composite structure of nanofibers and nanoparticles. The nanofiber membranes obtained in Examples 3 and 4 had structures similar to those in Example 1.

[0064] Comparative Example 1

[0065] In this comparative example, the nanofiber membrane PCL / GEL was prepared by directly adding 0.5 g of the polymer matrix GEL-PCL to 10 mL of water, stirring to prepare a spinning solution, and then performing electrospinning at a voltage of 8 kV and a flow rate of 0.25 mL / h.

[0066] Comparative Example 2

[0067] The preparation method of the photoelectric responsive antibacterial fiber membrane in this comparative example is as follows:

[0068] (1) Dissolve terephthalic acid in dichloroethane solution at a concentration of 0.05 mol / L and heat to 80℃. Add FeCl3 catalyst under N2 protection and stir to induce Friedel-Crafts crosslinking reaction. The molar ratio of terephthalic acid to FeCl3 is 1:2, the rotation speed is 350 r / min, and the reaction time is 24 h.

[0069] (2) After the reaction is complete, filter the turbid product with filter paper. During filtration, use anhydrous ethanol for initial rinsing, then place the product in a Soxhlet extractor for washing. Place the washed product in a drying oven for drying to ensure the removal of the catalyst, and obtain HCP nanospheres. Mix the HCP nanospheres with a 2% w / v methylene blue aqueous solution to allow HCP to adsorb methylene blue, and obtain methylene blue-loaded HCP nanospheres HCPs-MB;

[0070] (3) Add 0.5 g of polymer matrix GEL-PCL to 10 mL of water and stir to prepare a spinning solution; add the super-crosslinked polymer nanospheres loaded with polymethylene blue to the electrospinning solution and mix evenly to obtain an electrospray solution; the mass-volume ratio of the super-crosslinked polymer nanospheres loaded with polymethylene blue to the electrospinning solution is 1:100.

[0071] (4) Electrospinning was performed using a spinning solution. The electrospinning voltage was 8 kV and the flow rate was 0.25 mL / h. The nanofiber base membrane was obtained by receiving it on a roller receiver. Before the nanofiber base membrane was dried, the spinning head was replaced with an electrospray head, and an electrospray solution was used to perform in-situ electrospraying on the nanofiber base membrane. After drying, the photoelectric responsive antibacterial nanofiber membrane MB@HCPs-P / G was obtained.

[0072] Comparative Example 3

[0073] The preparation method of the photoelectric responsive antibacterial fiber membrane in this comparative example is similar to that in comparative example 2. The difference from comparative example 2 is that in step (2), the concentration of methylene blue aqueous solution is 5% w / v.

[0074] To evaluate the antibacterial activity of the membrane materials obtained in the examples and comparative examples, we selected *Escherichia coli* and *Staphylococcus aureus* as representative bacterial species for antibacterial experiments: First, 5 mg of equal masses of PCL-GEL, MB@HCPs-P / G, and PMB@HCPs-P / G nanofiber membranes were sterilized under ultraviolet light. Subsequently, 1 mL of a viable bacterial concentration of 10⁻⁶ was added to each nanofiber membrane. 7 A bacterial suspension of CFU / mL was used as the experimental group, and a blank bacterial suspension without nanofiber membrane treatment was set up as the control group (labeled Blank). Then, all experimental groups were exposed to a 660nm infrared lamp for 0 min, 5 min, 15 min, and 30 min. Afterwards, 100 μL of bacterial suspension from both the experimental and control groups was inoculated onto LB agar plates and incubated at 37℃ for 24 h. The number of colonies on the plates was counted, and the antibacterial properties of each nanofiber membrane were statistically analyzed. The antibacterial rate of the nanofiber membrane was calculated using the following formula:

[0075]

[0076] Where N represents the number of colonies in the blank group and n represents the number of colonies in the experimental group.

[0077] See Figure 4A typical Gram-negative bacterium, *Escherichia coli*, was selected for photoelectric response antibacterial studies. For the PCL / GEL group, after 30 minutes of infrared lamp irradiation, the number of *E. coli* bacteria did not change significantly, indicating that light irradiation does not induce apoptosis in *E. coli*. In the absence of infrared lamp irradiation and under the same irradiation time, the number of *E. coli* bacteria decreased in both the MB@HCPs-P / G and PMB@HCPs-P / G groups, with a more significant decrease in colony count in the PMB@HCPs-P / G group. This indicates that although MB has intrinsic antibacterial capabilities, the antibacterial effect of PMB@HCPs-P / G is more significant upon photostimulation. The inhibition rate of PMB@HCPs-P / G against *E. coli* reached 95.07% at 15 minutes of light irradiation and further increased to 99.44% at 30 minutes. This indicates that the PMB@HCPs-P / G composite nanofiber membrane has better photoelectric response antibacterial performance against *E. coli* than the MB@HCPs-P / G composite nanofiber membrane.

[0078] See Figure 5 For the Gram-positive bacterium Staphylococcus aureus, the antibacterial properties of the MB@HCPs-P / G and PMB@HCPs-P / G groups were similar to those of Escherichia coli, but with greater sensitivity. The inhibition rate of PMB@HCPs-P / G against Staphylococcus aureus reached 99.00% at 15 minutes of light exposure and further increased to 99.99% at 30 minutes. This indicates that the PMB@HCPs-P / G composite nanofiber membrane has better photoelectric response antibacterial properties against Staphylococcus aureus than the MB@HCPs-P / G composite nanofiber membrane.

[0079] The photodynamic therapy ROS of MB@HCPs-P / G and PMB@HCPs-P / G was investigated using the chemical probe 1,3-diphenylisobenzofuran (DPBF). 1 The production rate of O2. Under infrared light stimulation, MB can absorb photons and complete a transition. The energy released in this process combines with O2 and water to produce reactive oxygen species. See also Figure 6The ROS yield of the material was evaluated by reducing the absorbance of DPBF at 420 nm. When exposed to 660 nm infrared radiation, both MB@HCPs-P / G and PMB@HCPs-P / G generated reactive oxygen species (ROS), leading to significant decomposition of DPBF. The ROS generation rate in PMB@HCPs-P / G was faster than that in MB@HCPs-P / G. At 15 min, PMB@HCPs-P / G generated 56.96% ROS, significantly higher than the 30.02% generated by MB@HCPs-P / G. By 30 min, PMB@HCPs-P / G generated 69.26% ROS, while MB@HCPs-P / G generated 53.71%, essentially reaching its maximum generation rate. This indicates that the polymethylene blue-loaded nanofiber membrane generates more ROS under the same illumination conditions than the methylene blue-loaded nanofiber membrane, exhibiting better antibacterial properties.

[0080] The conductivity test results for different nanofiber membranes are shown in [reference]. Figure 7 The conductivity of a pure PCL / GEL film is only about 1.2 × 10⁻⁶. -4 S·cm -1 It exhibits typical insulating polymer properties, indicating that its intrinsic charge transport capability is relatively weak.

[0081] The conductivity of the MB@HCPs-P / G membrane material with introduced MB was significantly improved. Specifically, the conductivity of the 2% MB@HCPs-P / G membrane in Comparative Example 2 increased to approximately 3.8 × 10⁻⁶. -4 S·cm -1 When the amount of MB increased to 5%, the conductivity further increased to approximately 5.2 × 10⁻⁶. -4 S·cm -1 This improvement is mainly attributed to the positive charge carried by MB molecules and their promoting effect on ion migration and interfacial charge transfer, thereby forming more charge transport channels in the fiber network.

[0082] In contrast, the conductivity of the PMB@HCPs-P / G membrane material with PMB incorporation is significantly enhanced. The conductivity of the 2% PMB@HCPs-P / G membrane in Example 1 reaches approximately 6.2 × 10⁻⁶. -4 S·cm -1 The conductivity was significantly higher than that of the MB system with the same addition amount; when the PMB content was increased to 5%, the conductivity further increased to approximately 8.6 × 10⁻⁶. -4 S·cm -1 It is nearly 7 times better than pure PCL / GEL membrane.

[0083] The superior conductivity of the PMB system stems from its π-π stacking structure, which facilitates charge delocalization and transitions within the polymer backbone and between molecules, thereby creating more efficient electronic or quasi-electronic transport pathways. In contrast, monomeric MB primarily relies on localized ionic conductivity, resulting in relatively limited long-range charge transport capabilities in solid fiber membranes. For photoresponsive antibacterial systems, higher charge transport capabilities promote electron-hole separation and migration efficiency under illumination, thereby enhancing ROS generation and ultimately improving the photodynamic antibacterial properties of the membrane material.

[0084] When the PMB@HCPs-P / G prepared according to this invention is used as a wound dressing, its wound healing effect is significantly better than that of existing products. This advantage is due to the long-term effective release of photo-induced antibacterial factors by HCPs-PMB and the good breathability and biocompatibility of the nanofibers themselves.

[0085] Those skilled in the art should understand that variations can be implemented by combining existing technology with the above embodiments, which will not be elaborated here. Such variations do not affect the essence of the present invention, and will not be elaborated here either.

[0086] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and the devices and structures not described in detail should be understood as being implemented in a conventional manner in the art. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the present invention. This does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention's technical solutions still fall within the protection scope of the present invention.

Claims

1. A method for preparing a photoelectric responsive antibacterial nanofiber membrane, characterized in that: Includes the following steps: Step S1: Obtain hypercrosslinked polymer nanospheres through polymerization reaction; prepare a polymer solution with electrospinning properties as a spinning solution; Step S2: Mix the supercrosslinked polymer nanospheres with a methylene blue aqueous solution and stir thoroughly at room temperature in the dark until the supercrosslinked polymer nanospheres adsorb methylene blue to reach equilibrium. Step S3: Add ammonium persulfate solution to the solution in step S2 and stir thoroughly. After filtration, wash and dry to obtain supercrosslinked polymer nanospheres loaded with polymethylene blue. Step S4: Mix the polymer solution from step S1 with the supercrosslinked polymer nanospheres loaded with polymethylene blue to obtain an electrospray solution; Step S5: Electrospinning is performed using the spinning solution obtained in step S1 to form a nanofiber base film. Then, the electrospray solution is quickly switched in situ to perform electrospraying on the nanofiber base film to obtain a photoelectric responsive antibacterial nanofiber film.

2. The method for preparing a photoelectric responsive antibacterial nanofiber membrane according to claim 1, characterized in that, In step S5, electrospinning and electrospraying are performed alternately several times to obtain a multilayer composite photoelectric responsive antibacterial nanofiber membrane.

3. The method for preparing a photoelectric responsive antibacterial nanofiber membrane according to claim 1 or 2, characterized in that, The polymer in step S1 is one or more of polycaprolactone, gelatin, polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, polylactic acid, and carboxymethyl cellulose.

4. The method for preparing a photoelectric responsive antibacterial nanofiber membrane according to claim 3, characterized in that, The hypercrosslinked polymer nanospheres are obtained by catalytic polymerization of aromatic hydrocarbon monomers. The preparation process includes: dissolving aromatic hydrocarbon monomers in dichloroethane and heating them; adding FeCl3 catalyst under an inert atmosphere and stirring to induce a Friedel-Crafts crosslinking reaction; filtering, washing and drying after the reaction to obtain hypercrosslinked polymer nanospheres.

5. The method for preparing a photoelectric responsive antibacterial nanofiber membrane according to claim 4, characterized in that, The aromatic hydrocarbon monomer is one of terephthalic acid, 1-naphthaleneethanol, 9-anthraciteethanol, and 1-pyreneethanol, and the concentration of the aromatic hydrocarbon monomer is 0.05 mol / L; the aromatic hydrocarbon monomer is dissolved in dichloroethane and heated to 80°C; the molar ratio of the aromatic hydrocarbon monomer to FeCl3 is 1:

2.

6. The method for preparing a photoelectric responsive antibacterial nanofiber membrane according to claim 1 or 2, characterized in that, In step S2, the concentration of methylene blue in the aqueous solution is 2-9 w / v.

7. The method for preparing a photoelectric responsive antibacterial nanofiber membrane according to claim 1 or 2, characterized in that, In step S4, the mass-to-volume ratio of the supercrosslinked polymer nanospheres loaded with polymethylene blue to the polymer solution is 1:

100.

8. A photoelectric responsive antibacterial nanofiber membrane, characterized in that: The photoelectric responsive antibacterial nanofiber membrane was prepared by the method described in any one of claims 1 to 7. Nanofibers interweave to form a thin film framework; nanoparticles are loaded on the surface and between the nanofibers. The nanofibers and nanoparticles are firmly linked by the same polymer. The nanoparticles contain photo-responsive antibacterial functional materials; the photo-responsive antibacterial functional materials include hypercrosslinked polymer nanospheres loaded with polymethylene blue.

9. The photoelectric responsive antibacterial nanofiber membrane according to claim 8, characterized in that, The nanofibers are composed of one or more of polycaprolactone, gelatin, polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, polylactic acid, and carboxymethyl cellulose; the hypercrosslinked polymer nanospheres are obtained by catalytic polymerization of aromatic hydrocarbon monomers; the aromatic hydrocarbon monomers are one of terephthalic acid, 1-naphthalimethanol, 9-anthraphthalimethanol, and 1-pyreneethanol.

10. The application of a photoelectric responsive antibacterial nanofiber membrane as a biological antibacterial dressing, characterized in that, The photoelectric responsive antibacterial nanofiber membrane is the photoelectric responsive antibacterial nanofiber membrane as described in claim 8 or 9.

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