A photodynamic antibacterial fiber membrane and its preparation method and application

Abstract

This application discloses a photodynamic antibacterial fiber membrane and its preparation method and application, which relates to the field of functional materials, including: dissolving aggregation-induced luminescence photosensitive molecules in a first solvent to obtain a photosensitive molecule solution; dissolving the purified polymer in a second solvent and adding the photosensitive molecule solution to obtain a spinning precursor; regulating the orientation of the spinning precursor by electrospinning to obtain a fiber membrane; and regulating the crystallinity of the fiber membrane to obtain a photodynamic antibacterial fiber membrane. The preparation method provided in this application combines the polymer condensed state structure with aggregation-induced luminescence photosensitive molecules, using the polymer crystallization and orientation structure to provide a rigid confined domain for the photosensitive molecules; at the same time, the nanoscale of the electrospun fiber membrane is used to increase the contact area between the material and oxygen, synergistically improving the material's active oxygen yield.

Description

Technical Field

[0001] The present application relates to the field of functional materials, and in particular to a photodynamic antibacterial fiber membrane and its preparation method and application. Background Art

[0002] Photodynamic antimicrobial therapy (PDA) utilizes the reactive oxygen species (ROS) generated by photosensitizers under light irradiation to destroy bacterial structures and achieve sterilization. Compared to traditional antibiotic antimicrobial methods, PDA offers advantages such as high spatiotemporal selectivity, non-invasiveness, resistance resistance, and broad-spectrum bactericidal activity. The choice of photosensitizer is crucial for PDA. Organic photosensitizers are widely used due to their broad wavelength absorption, enhanced tissue penetration, higher selectivity, and improved biocompatibility. However, traditional organic photosensitizers such as porphyrins and phthalocyanines possess a planar, rigid π-conjugated structure, which can lead to fluorescence quenching (ACQ) in the aggregated state, often requiring encapsulation with a carrier to prevent this. In contrast, aggregation-induced emission (AIE) molecules offer a promising solution to the ACQ problem, as AIE molecules typically possess highly distorted structures and rich rotational and vibrational motions. In the aggregated state, non-radiative decay pathways are blocked, which increases the probability of single excited states and subsequent intersystem crossing (ISC) processes, thereby facilitating the use of more energy in the generation of reactive oxygen species.

[0003] In order to further enhance the photodynamic therapy effect of AIE photosensitizers, a rigid structure is often designed to provide a confined microenvironment, which is mainly used to limit the intramolecular motion of AIE molecules to increase their reactive oxygen production rate. However, as a polymer matrix, fibers can easily obtain orientation and crystallization structure during the processing and manufacturing process, and can provide a rigid confining structure for the molecules; secondly, because it has a large surface area, it is conducive to the large-area distribution of photosensitizers and large-area contact with the surrounding environment, further improving the efficiency of photodynamic therapy. At the same time, due to the fixation of photosensitizers by the fiber structure, it can also play a certain sustained-release role, extending the service life of antibacterial materials. At present, there are two main forms of fibers used as photosensitive molecule carriers: one is to directly dip the personal protective equipment fabric into photosensitive molecules; the other is to electrospin the photosensitizers and polymers into nanofiber membranes after blending.

[0004] However, existing studies have only simply mixed photosensitizer molecules with polymers or directly attached the molecules to fabrics, which may have problems such as weak restriction effect or easy elution of photosensitizer molecules, resulting in low reactive oxygen production. Summary of the Invention

[0005] In order to solve the above-mentioned technical problems existing in the prior art, the present application provides a photodynamic antibacterial fiber membrane and its preparation method and application, so as to overcome the technical problems in the prior art such as low active oxygen production rate, easy elution of photosensitive molecules, and poor photostability of photodynamic antibacterial fabrics.

[0006] In order to achieve the above objectives, the technical solutions of the embodiments of the present application are:

[0007] The first aspect of the present application provides a method for preparing a photodynamic antibacterial fiber membrane, comprising:

[0008] dissolving aggregation-induced luminescence photosensitive molecules in a first solvent to obtain a photosensitive molecule solution;

[0009] dissolving the purified polymer in a second solvent, and adding the photosensitive molecule solution to obtain a spinning precursor solution;

[0010] Controlling the orientation of the spinning precursor solution by electrospinning to obtain a fiber membrane;

[0011] The crystallinity of the fiber membrane is controlled to obtain a photodynamic antibacterial fiber membrane.

[0012] In combination with the first aspect, preferably, the polymer is L-polylactic acid, and the structural formula of the L-polylactic acid is:

[0013]

[0014] In combination with the first aspect, preferably, the structural formula of the aggregation-induced luminescence photosensitive molecule is:

[0015]

[0016] In combination with the first aspect, preferably, the first solvent is one or more of dimethyl sulfoxide and N,N-dimethylformamide; and / or, the second solvent is one or more of chloroform and dichloromethane.

[0017] In combination with the first aspect, preferably, the content of the polymer in the spinning precursor solution is 8-12 wt%; the content of the aggregation-induced emission photosensitive molecules in the spinning precursor solution is 1-2 wt%.

[0018] In combination with the first aspect, preferably, the volume ratio of the first solvent to the second solvent is 1:4.

[0019] In combination with the first aspect, preferably, the orientation control by electrospinning includes: the spinning voltage is 18-22kV, the propulsion speed is 0.8-1.2mL / h, the receiving distance from the needle to the roller is 14-16cm, the receiving speed of the roller is 300rpm, 600rpm, and 900rpm respectively, and the spinning time is 3h-4h.

[0020] In combination with the first aspect, preferably, when the crystallization degree is controlled, the crystallization temperature is 125-130° C., and the crystallization time is 0 min, 30 min, 60 min and 90 min.

[0021] The second aspect of the present application provides a photodynamic antibacterial fiber membrane as described in the first aspect.

[0022] The third aspect of the present application provides a use of the photodynamic antibacterial fiber membrane prepared by the method of the first aspect or the photodynamic antibacterial fiber membrane of the second aspect in preparing polymer materials.

[0023] Compared with the prior art, the advantages or beneficial effects of the embodiments of the present application include at least:

[0024] The preparation method provided in this application, on the one hand, combines the polymer condensed state structure with the aggregation-induced luminescence photosensitive molecules, and uses the polymer crystallization and orientation structure to provide a rigid confined domain for the photosensitive molecules; on the other hand, it uses the nanoscale of the electrospun fiber membrane to increase the contact area between the material and oxygen, and synergistically improves the active oxygen yield of the material to obtain a fiber membrane material with high-efficiency photodynamic antibacterial properties; thirdly, compared with traditional materials that use antibiotics for antibacterial purposes, it can effectively circumvent bacterial resistance, and at the same time has the advantages of high spatiotemporal selectivity, non-invasiveness and spectral sterilization.

[0025] The photodynamic antibacterial fiber membrane prepared in this application, which regulates the polymer condensed state structure to increase the active oxygen production rate of photosensitizer molecules, can be used as a material for air purification, personal protection and photodynamic wound dressing, and has a certain degree of photostability. After being recycled 10 times, the active oxygen production rate of the material can still be maintained at almost the initial level. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the preparation process of the photodynamic antibacterial fiber membrane provided in the embodiment of the present application;

[0027] Figure 2 The scanning electron microscope images and orientation distribution diagrams of the antibacterial fiber membranes with different orientation degrees prepared in Example 1;

[0028] Figure 3 The scanning electron microscope images and diameter statistics of the antibacterial fiber membranes with different orientation degrees prepared in Example 1 at a receiving drum speed of 900 rpm;

[0029] Figure 4 This is a characterization diagram of the crystallinity of the photodynamic antibacterial fiber membrane at different isothermal crystallization times in Example 2;

[0030] Figure 5The water contact angle diagrams of the photodynamic antibacterial fiber membrane of Example 2 are at a receiving drum speed of 900 rpm and after isothermal crystallization for 0 min and 90 min respectively;

[0031] Figure 6 This is a data graph of singlet oxygen yield of the photodynamic antibacterial fiber membrane of Example 2 at a receiving drum speed of 900 rpm and after isothermal crystallization for 0 min and 90 min respectively;

[0032] Figure 7 This is a data graph showing the singlet oxygen yield of the photodynamic antibacterial fiber membrane of Example 2 after the receiving drum rotates at 900 rpm, isothermal crystallization is performed for 90 minutes, and 11 cycles of irradiation are performed;

[0033] Figure 8 This is a characterization diagram of the antibacterial effects of pure electrospun fiber membrane, antibacterial fiber membrane with a receiving drum speed of 300 rpm without isothermal crystallization treatment, and antibacterial fiber membrane with a 90-min isothermal crystallization treatment and a receiving drum speed of 900 rpm on Staphylococcus aureus and Escherichia coli. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limiting this application. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0035] In the following description, reference is made to "some embodiments," which describe a subset of all possible embodiments. However, it will be understood that "some embodiments" may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict. Unless otherwise defined, all technical and scientific terms used in the embodiments of this application have the same meaning as commonly understood by those skilled in the art to which the embodiments of this application pertain. The terms used in the embodiments of this application are for the purpose of describing the embodiments of this application only and are not intended to limit this application.

[0036] In the following description of this embodiment, the terms "include", "comprising", "having" and "containing" are open-ended terms, meaning including but not limited to.

[0037] It should be noted that all raw materials / reagents in the examples of the present application can be purchased on the market or prepared according to conventional methods familiar to those skilled in the art; the term "and / or" in the examples of the present application is only used to describe the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B represents three situations: A exists alone, B exists alone, and A and B exist at the same time, wherein A and B can be singular or plural, and the character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship.

[0038] In the following description of this embodiment, the term "at least one" refers to one or more, and "plurality" refers to two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0039] Those skilled in the art should understand that in the following description of the embodiments of the present application, the order of serial numbers does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0040] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0041] It will be understood by those skilled in the art that the numerical ranges in the examples of this application are to be understood as also specifically disclosing each intermediate value between the upper and lower limits of the ranges. Each smaller range between any stated value and the intermediate value in the stated range, as well as any other stated value or intermediate value in the stated range, is also encompassed by this application. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

[0042] Unless otherwise indicated, the technical / scientific terms used herein have the same meanings as those generally understood by those skilled in the art described in this application. Although this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the embodiments or test examples of this application. All documents mentioned in this specification are generally incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of any conflict with any incorporated document, the content of this application shall prevail.

[0043] It should be noted that all raw materials and / or reagents in the examples of the present application were purchased on the market or prepared according to conventional methods well known to those skilled in the art.

[0044] In a first aspect, an embodiment of the present application provides a method for preparing a photodynamic antibacterial fiber membrane, the preparation method comprising:

[0045] dissolving aggregation-induced luminescence photosensitive molecules in a first solvent to obtain a photosensitive molecule solution;

[0046] dissolving the purified polymer in a second solvent, and adding the photosensitive molecule solution to obtain a spinning precursor solution;

[0047] Controlling the orientation of the spinning precursor solution by electrospinning to obtain a fiber membrane;

[0048] The crystallinity of the fiber membrane is controlled to obtain a photodynamic antibacterial fiber membrane.

[0049] The preparation method provided in the embodiments of the present application, on the one hand, combines the polymer condensed state structure with the aggregation-induced luminescence photosensitive molecules, and uses the polymer crystallization and orientation structure to provide a rigid confined domain for the photosensitive molecules; on the other hand, it uses the nanoscale of the electrospun fiber membrane to increase the contact area between the material and oxygen, and synergistically improves the active oxygen yield of the material to obtain a fiber membrane material with high-efficiency photodynamic antibacterial properties; thirdly, compared with traditional materials that use antibiotics for antibacterial purposes, it can effectively circumvent bacterial resistance, and at the same time has the advantages of high spatiotemporal selectivity, non-invasiveness and spectral sterilization.

[0050] Figure 1 Schematic diagram of the preparation process of the photodynamic antibacterial fiber membrane provided in the embodiment of the present application. Figure 2 These are the scanning electron microscope images and orientation distribution diagrams of the antibacterial fiber membranes with different orientation degrees prepared in Example 1.

[0051] In a specific embodiment, the polymer in the embodiment of the present application is preferably poly (L-lactic acid), and the structural formula of poly (L-lactic acid) is preferably:

[0052]

[0053] The structural formula of L-polylactic acid is selected in the examples of the present application because its unique semi-crystalline structure and orientation structure provide rigid confined domains for the photosensitive molecules.

[0054] In a specific embodiment, the structural formula of the aggregation-induced emission photosensitive molecule (DPA-SCP) in the embodiment of the present application is preferably:

[0055]

[0056] The embodiment of the present application selects the aggregation-induced luminescence photosensitizer of this structural formula because its distorted molecular structure can avoid the problem of low reactive oxygen yield caused by aggregation quenching of traditional photosensitizers with planar rigid π conjugated structures. At the same time, the photosensitive molecule is cleverly designed with α-cyanostilbene as the AIE skeleton and diphenylamine as a strong electron donor, and a strong electron donor-acceptor part is designed to obtain an AIE luminescent source with wide color tunability in the visible light range, thereby achieving a white light-driven photodynamic sterilization effect. At the same time, the positive ions of the pyridinium salt are conducive to anchoring bacteria (most of the bacterial surfaces are negatively charged), which is beneficial to its antibacterial effect.

[0057] It should be noted that the present application regulates the orientation and crystallinity of the polymer by electrospinning and isothermal crystallization to enhance the active oxygen yield of the photosensitive molecules. At the same time, the nanofiber structure is used to increase the oxygen contact area and maintain the photostability of the photosensitizer, thereby further improving the photodynamic antibacterial efficiency of the fiber membrane.

[0058] In a specific embodiment, the first solvent in the embodiment of the present application is preferably one of dimethyl sulfoxide and N,N-dimethylformamide.

[0059] It should be noted that the first solvent is a high boiling point solvent.

[0060] In a specific embodiment, the second solvent in the embodiments of the present application is preferably one of chloroform and dichloromethane.

[0061] It should be noted that the second solvent is a low boiling point solvent.

[0062] In a specific embodiment, the content of the polymer in the spinning precursor solution in the embodiment of the present application is preferably 8-12 wt %; the content of the aggregation-induced emission photosensitive molecules in the spinning precursor solution is preferably 1-2 wt %.

[0063] Among them, when the polymer content in the spinning precursor is less than 8wt%, the polymer molecular chains in the spinning precursor lack sufficient entanglement and cannot form a continuous electrostatic jet, and fibers with beads will be obtained, thereby affecting the fiber morphology; when the polymer content in the spinning precursor is greater than 12wt%, the fiber diameter will become coarser and cannot be maintained at the nanometer level, and the uniformity of the fiber will also deteriorate.

[0064] In a specific embodiment, the volume ratio of the first solvent to the second solvent in the embodiment of the present application is preferably 1:4.

[0065] Among them, when the volume ratio of the first solvent and the second solvent is less than 1:4, since the second solvent is a low-boiling-point solvent, when its content increases, the overall boiling point of the spinning precursor will decrease, which can easily cause needle blockage during the spinning process; when the volume ratio of the first solvent and the second solvent is greater than 1:4, since the first solvent has a low solubility in the polymer, it will cause partial precipitation of the polymer, affecting the uniformity of the spinning precursor.

[0066] In a specific embodiment, the orientation degree control by electrospinning in the embodiment of the present application is preferably: the spinning voltage is 18-22 kV, the propulsion speed is 0.8-1.2 mL / h, the receiving distance from the needle to the roller is 14-16 cm, the receiving speeds of the roller are 300 rpm, 600 rpm, and 900 rpm respectively, and the spinning time is 3h-4h.

[0067] In one embodiment of the present application, photodynamic antibacterial fiber membranes with different orientation degrees were prepared by electrospinning technology. As the rotation speed of the spinning collection drum increased from 300 rpm to 900 rpm, the orientation degree increased from 63% to 87%.

[0068] In one embodiment of the present application, the crystallinity of the antibacterial fiber membrane is changed by isothermal crystallization treatment of the photodynamic antibacterial fiber membrane. As the subsequent isothermal crystallization time increases from 0 min to 90 min, the crystallinity also increases from 14.3% to 53.9%.

[0069] In one embodiment of the present application, the singlet oxygen indicator 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA) was used to detect the active oxygen yield of different antibacterial fiber membranes, reflecting that different orientations and crystal structures have different degrees of rigid restriction on the AIE photosensitive molecules contained therein.

[0070] In one embodiment of the present application, the prepared photodynamic antibacterial fiber membrane simulates the outermost layer of a mask to test its antibacterial effect on Gram-positive bacteria - Staphylococcus aureus and Gram-negative bacteria - Escherichia coli, reflecting the broad-spectrum sterilization property of the antibacterial fiber membrane.

[0071] In a specific embodiment, when the crystallinity is regulated in the embodiment of the present application, the crystallization temperature is preferably 125-130° C., and the crystallization time is preferably 0 min, 30 min, 60 min and 90 min.

[0072] In a second aspect, an embodiment of the present application provides a photodynamic antibacterial fiber membrane prepared by the method described in the first aspect.

[0073] In a third aspect, embodiments of the present application provide a use of the photodynamic antibacterial fiber membrane prepared by the method of the first aspect or the photodynamic antibacterial fiber membrane of the second aspect in preparing polymer materials.

[0074] The technical method of the present application will be further described below with reference to specific embodiments.

[0075] Example 1

[0076] This embodiment provides a method for preparing antibacterial fiber membranes with different orientation degrees, and the specific steps are as follows:

[0077] (1) dissolving aggregation-induced luminescence photosensitive molecules in a first solvent to obtain a photosensitive molecule solution:

[0078] 6 mg of DPA-SCP molecules were weighed and added to 1.2 mL of dimethyl sulfoxide (DMSO) solution. The DPA-SCP molecules were completely dissolved by ultrasonication at room temperature for 5 min to obtain a photosensitive molecular solution.

[0079] (2) dissolving the purified polymer in a second solvent, and adding the photosensitive molecule solution to obtain a spinning precursor solution:

[0080] 1 g of L-polylactic acid pellets was added to 20 mL of chloroform solvent to prepare a 50 mg / mL solution. The magnetic speed was 1800 rpm and the stirring temperature was 25°C. After stirring until completely dissolved, the mixed solution was pipetted into 200 mL of methanol solution for precipitation while continuing to stir. After the precipitate was precipitated, it was soaked again with methanol solution and then taken out and placed in a clean glass culture dish. Tin foil was covered on the culture dish and small holes were poked in the tin foil. The culture dish was placed in a vacuum oven at 55°C for 24 hours and then taken out to obtain the purified L-polylactic acid raw material, that is, the purified polymer.

[0081] Weigh 600 mg of purified L-polylactic acid and add it to 4.8 mL of chloroform solvent to prepare a 100 mg / mL solution. The magnetic speed is 1800 rpm and the stirring temperature is 25°C. After stirring until completely dissolved, 1.2 mL of the prepared photosensitive molecule solution is mixed with it and continued stirring until uniform to obtain a spinning precursor solution.

[0082] (3) Orienting the spinning precursor solution by electrospinning to obtain a fiber membrane:

[0083] The prepared spinning precursor liquid was poured into a 10mL syringe, and a 23G needle with an inner diameter of 0.6mm was selected; the spinning voltage was 20kV, the propulsion speed was 1.0mL / h, the distance from the needle to the roller receiving was 15cm, the roller receiving speed was 300rpm, the receiving substrate was release paper, and the spinning time was 4h to prepare a photodynamic antibacterial fiber membrane.

[0084] The present application obtains antibacterial fiber membranes with different orientation degrees by changing the roller receiving speed, namely 600 rpm and 900 rpm respectively.

[0085] The obtained fiber membrane was placed in an oven at 60° C. and dried for 24 h to remove the residual solvent, thereby obtaining antibacterial fiber membranes with different degrees of orientation.

[0086] The prepared antibacterial fiber films with different orientations were peeled off from the release paper, and the orientations of the antibacterial fiber films with different orientations were characterized using an 18KW rotating target X-ray diffractometer (D / max-2550VB+ / PC). Figure 3 As shown, Figure 3 Scanning electron microscope image and diameter statistics graph of the antibacterial fiber membrane prepared in Example 1 at a drum speed of 900 rpm.

[0087] according to Figure 3 It can be seen that the electrospun antibacterial fiber membrane collected at a drum speed of 900 rpm is uniform in thickness and has obvious orientation, and the diameter of a single fiber is distributed in the range of 300-600 nm.

[0088] Example 2

[0089] This embodiment 2 provides a method for preparing a photodynamic antibacterial fiber membrane, and the specific steps are as follows:

[0090] The highly oriented antibacterial fiber membrane prepared in Example 1 at a receiving drum speed of 900 rpm was peeled off from the release paper, wrapped with tin foil, and placed on a 130°C hot plate for isothermal crystallization for 0 min, 30 min, 60 min, and 90 min. The crystallinity of the fiber membrane was tested using an in-situ electrochemical X-ray diffractometer (D8Advance / D8Advance). The crystallinity of the fiber membrane at different isothermal crystallization times was as follows: Figure 4 shown. Figure 4 This is a characterization diagram of the crystallinity of the photodynamic antibacterial fiber membrane at different isothermal crystallization times in Example 2.

[0091] according to Figure 4 It can be seen that with the increase of isothermal crystallization time, the crystallinity of the antibacterial fiber membrane continues to increase. The crystallinity of the antibacterial fiber membrane after isothermal crystallization for 0min, 30min, 60min and 90min are 14.3%, 37.7%, 44.9% and 53.9%, respectively.

[0092] Figure 5 These are water contact angle diagrams of the photodynamic antibacterial fiber membrane of Example 2 at a receiving drum speed of 900 rpm and after isothermal crystallization for 0 min and 90 min, respectively.

[0093] according to Figure 5 It can be seen that the hydrophilicity and hydrophobicity of the photodynamic antibacterial fiber membrane did not change significantly before and after crystallization, and the water contact angle remained at around 138°.

[0094] In order to verify the active oxygen production rate of the antibacterial fiber membranes with different orientations and the photodynamic antibacterial fiber membranes prepared in Examples 1-2 of the present application, the active oxygen production rate of the antibacterial fiber membranes with different orientations and the photodynamic antibacterial fiber membranes provided in the examples of the present application was characterized. The results are as follows: Figure 6 shown. Figure 6 The singlet oxygen yield data graph of the low-oriented and low-crystalline antibacterial fiber membrane prepared in Example 1 with a receiving drum speed of 300 rpm and no isothermal crystallization treatment, and the high-oriented and high-crystalline photodynamic antibacterial fiber membrane prepared in Example 2 with a receiving drum speed of 900 rpm and isothermal crystallization for 90 minutes after 12 minutes of simulated sunlight irradiation.

[0095] In this application, the fiber membranes prepared in Example 1 and Example 2 were cut into samples of 2.5 cm × 2.5 cm size for characterization of active oxygen yield. The indicator used was the singlet oxygen indicator 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA). The characterization principle is that ABDA can react with singlet oxygen, and the decrease in indicator concentration leads to a decrease in its ultraviolet absorbance. It was dissolved in DMSO solution to prepare a 25 μM stock solution, and then diluted with deionized water to 5×10 -5 Each sample was placed in 2 mL of the indicator and the irradiance was 80 mW / cm 2 The samples were irradiated with a white light source simulating sunlight for 12 minutes, and the difference in UV absorbance after irradiation was compared with the original absorbance. The UV spectrophotometer used was a Lanbda A35.

[0096] according to Figure 6 It can be seen that the degree of decrease in ultraviolet absorbance of the high-oriented and high-crystalline antibacterial fiber membrane after 90 minutes of isothermal crystallization at a receiving speed of 900 rpm and 12 minutes of simulated sunlight irradiation is much greater than that of the low-oriented and low-crystalline antibacterial fiber membrane at a receiving speed of 300 rpm without isothermal crystallization treatment, indicating that the restrictive effect of orientation and crystal structure on photosensitizer molecules significantly increases its active oxygen production rate.

[0097] In order to verify the photostability of the photodynamic antibacterial fiber membrane prepared in Example 2 of the present application, the photostability of the photodynamic antibacterial fiber membrane prepared in Example 2 was verified. The results are as follows: Figure 7 As shown, Figure 7 This is a data graph of singlet oxygen yield of the photodynamic antibacterial fiber membrane of Example 2 after the receiving drum rotates at 900 rpm, isothermal crystallization is performed for 90 minutes, and 11 cycles of irradiation are performed.

[0098] The photodynamic antibacterial fiber membrane sample with a drum collection speed of 900 rpm and a crystallization time of 90 min in Example 2 was selected, and the indicator used was the singlet oxygen indicator with the same concentration and dosage as in Example 2. The same antibacterial fiber membrane sample was subjected to 11 cycles of irradiation and singlet oxygen yield detection. The light source used in each cycle was a radiant illumination of 80 mW / cm 2 The irradiation time for each cycle is 12 minutes.

[0099] according to Figure 7 It can be seen that after 11 irradiation cycles, there is no obvious change in the degree of decrease in the absorbance of the ABDA indicator, and it can still be maintained at 80% of the initial value, that is, the singlet oxygen yield of the sample can still be maintained at the initial level under multiple cycles of illumination, indicating that the highly crystalline and highly oriented antibacterial fiber membrane prepared in this application has excellent light stability.

[0100] Three groups of samples were used for control experiments: pure PLLA electrospun fiber membrane, antibacterial fiber membrane without isothermal crystallization treatment and with a receiving drum speed of 300 rpm, and antibacterial fiber membrane with a receiving drum speed of 900 rpm for 90 minutes (specifications: 2.5 cm × 2.5 cm). 6 A bacterial solution with a CFU / mL concentration was used to simulate bacterial aerosols in the environment. 50 μL of bacterial solution was sprayed on each sample, and then the sample was exposed to simulated sunlight (80 mW cm -2 After 15 minutes of exposure to white light, the samples were placed in a 37°C constant temperature and humidity chamber for 24 hours. Bacteria on the membrane surface were then collected with PBS buffer and cultured at 37°C for 24 hours. The number of colonies in each group was observed using conventional plates. Figure 8 This is a characterization diagram of the antibacterial effects of pure electrospun fiber membrane, antibacterial fiber membrane with a receiving drum speed of 300 rpm without isothermal crystallization treatment, and antibacterial fiber membrane with a 90-min isothermal crystallization treatment and a receiving drum speed of 900 rpm on Staphylococcus aureus and Escherichia coli.

[0101] according to Figure 8 It can be seen that pure PLLA electrospun fiber membrane and antibacterial fiber membrane without isothermal crystallization treatment did not show obvious antibacterial effect, while the highly oriented and highly crystallized antibacterial fiber membrane showed obvious antibacterial effect against Staphylococcus aureus and Escherichia coli under light conditions, reflecting the broad-spectrum photodynamic sterilization performance of the antibacterial fiber membrane.

[0102] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for preparing a photodynamic antibacterial fiber membrane, characterized in that: include: dissolving aggregation-induced luminescence photosensitive molecules in a first solvent to obtain a photosensitive molecule solution; dissolving the purified polymer in a second solvent, and adding the photosensitive molecule solution to obtain a spinning precursor solution; Controlling the orientation of the spinning precursor solution by electrospinning to obtain a fiber membrane; The crystallinity of the fiber membrane obtained by electrospinning is controlled to obtain a photodynamic antibacterial fiber membrane; The polymer is poly (L-lactic acid), and the structural formula of the poly (L-lactic acid) is: The structural formula of the aggregation-induced luminescence photosensitive molecule is: The content of the polymer in the spinning precursor solution is 8-12 wt%; The content of the aggregation-induced luminescence photosensitizer in the spinning precursor solution is 1-2 wt %; The orientation control by electrospinning includes: a spinning voltage of 18-22 kV, a propulsion speed of 0.8-1.2 mL / h, a receiving distance from the needle to the roller of 14-16 cm, a receiving speed of the roller of 900 rpm, and a spinning time of 3 h-4 h; When the crystallinity is controlled, the crystallization is isothermal crystallization, the crystallization temperature is 125-130° C., and the crystallization time is 90 min.

2. The method for preparing the photodynamic antibacterial fiber membrane according to claim 1, characterized in that: The first solvent is one or both of dimethyl sulfoxide and N,N-dimethylformamide; The second solvent is one or both of chloroform and dichloromethane.

3. The method for preparing the photodynamic antibacterial fiber membrane according to claim 1, characterized in that: The volume ratio of the first solvent to the second solvent is 1:

4.

4. A photodynamic antibacterial fiber membrane prepared according to any one of claims 1 to 3.

5. Use of the photodynamic antibacterial fiber membrane according to claim 4 in preparing functional materials.

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