A degradable nanofiber membrane material having a hydrophilic inner core and a hydrophobic outer shell and a method of making the same

Abstract

The application relates to a degradable nanofiber membrane material with a hydrophilic inner core and a hydrophobic shell and a preparation method thereof, and belongs to the technical field of medical biomaterials. The preparation method comprises the following steps: (1) preparing a sericin powder; (2) preparing a sericin and polyvinyl alcohol core layer mixed solution by taking water as a solvent; (3) preparing a polylactic acid-glycolic acid copolymer shell layer solution; (4) preparing a composite nanofiber with a core-shell structure through coaxial electrospinning technology; and (5) preparing a bacteriostatic coating. The prepared degradable nanofiber has a hydrophilic inner core and a hydrophobic shell, can load water-soluble drugs in the core layer, solves the problem that hydrophilic drugs are difficult to dissolve and disperse, has good bacteriostatic effect and no cytotoxicity, and can be applied to the fields of wound dressings, hemostatic materials, stent materials and drug release. The preparation method is simple and efficient, has good continuity and uniformity, and is green and environment-friendly in the production process.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of medical biomaterials, and particularly relates to a degradable nanofiber membrane material with a hydrophilic inner core and a hydrophobic outer shell and a preparation method thereof. BACKGROUND

[0002] Nanofibers have the characteristics of large specific surface area and high porosity, and are widely used in the fields of drug release and tissue engineering. Nanofibers with good biocompatibility and biodegradability are similar to the extracellular matrix of the body, can avoid rejection, and are more suitable for use as drug release carriers. Poly(lactic-co-glycolic acid) is a biocompatible and biodegradable polymer, and its degradation products are carbon dioxide and water, which can be degraded and absorbed by the body without adverse reactions. Poly(lactic-co-glycolic acid) retains the rigidity, hydrophobicity, extensibility and slow degradation of lactic acid, and has the characteristics of fast degradation of glycolic acid. By changing the ratio of lactic acid and glycolic acid monomers, the molecular weight, concentration and end groups of the polymer, the properties of poly(lactic-co-glycolic acid) can be adjusted to change its drug loading rate, encapsulation efficiency and drug release behavior.

[0003] Compared with traditional drug-loaded materials, nanofibers with core-shell structure (CSF) can encapsulate drugs inside the fibers, which can not only encapsulate drugs well and maintain drug activity, but also can effectively regulate the slow release of the encapsulated drugs inside due to the protection of the shell material, avoiding burst release and reducing the toxic and side effects of drugs. In the research and application of core-shell structure nanofiber drug release, the types of loaded or released drugs are various, including hydrophobic drugs such as paclitaxel, rifampicin, propranolol, ketoprofen, metronidazole and dipyridamole; hydrophilic drugs such as amoxicillin, doxorubicin hydrochloride, tobramycin, dexamethasone and ampicillin; biological macromolecules such as polysaccharides, proteins, DNA and growth factors. For drugs that are soluble in conventional organic solvents, the drugs can be co-dissolved with the polymer material in an organic solvent, and then nanofiber membranes or capsules can be prepared to allow the drugs to be released slowly. The patent with publication number CN111705377A prepared a degradable nanofiber with a microporous core-shell structure by using modified chitosan as the shell and polylactic acid as the core, which can co-dissolve the drug with the core material polylactic acid, and thus be applied in drug release and wound dressing fields. The special microporous structure is more conducive to cell proliferation, differentiation and tissue ingrowth. However, there are few studies on water-soluble drug release materials, mainly because hydrophilic drugs are generally dissolved in water as the core layer for spinning, and the shell layer is usually a hydrophobic polymer dissolved in an organic solvent as a carrier. During the spinning process, part of the shell spinning solution may precipitate when it comes into contact with the water-soluble core layer, making it difficult to prepare.

[0004] Therefore, for the application research of drug-loaded materials, how to control the release of both hydrophilic drugs and hydrophobic drugs is the research focus in the future. SUMMARY

[0005] In order to prepare a drug-loaded sustained-release material that can load both hydrophilic drugs and hydrophobic drugs, the application provides a degradable nanofiber membrane material with a hydrophilic inner core and a hydrophobic shell, and simultaneously provides a preparation method of the degradable nanofiber membrane material.

[0006] The degradable nanofiber membrane material with a hydrophilic inner core and a hydrophobic shell has a core-shell structure, the core layer is a hydrophilic silk fibroin and polyvinyl alcohol composite hydrogel, and the shell layer is a hydrophobic polylactic acid-glycolic acid copolymer with good biocompatibility and biodegradability.

[0007] The porosity of the degradable nanofiber membrane material is 32%, the nanofiber surface is smooth and uniform, the diameter is 800-1300 nm, the inner diameter of the core layer is 250-350 nm, and the inner diameter of the shell layer is 500-650 nm.

[0008] The degradable nanofiber membrane material has good antibacterial effect and biocompatibility, and is suitable for wound dressings, hemostatic materials and drug sustained-release materials.

[0009] The preparation steps of the degradable nanofiber membrane material with a hydrophilic inner core and a hydrophobic shell are as follows:

[0010] (1) Extracting silk fibroin

[0011] 20g of silk is cut into fragments and placed in 500mL of 0.02-0.05mol / L sodium carbonate solution or deionized water, boiled in a constant temperature water bath at 100℃ for 1h, centrifuged to remove the precipitate, and a clear silk fibroin solution was obtained; the silk fibroin solution was poured into a dialysis bag and placed in deionized water for dialysis; vacuum freeze-drying was performed to obtain silk fibroin powder, which was stored at low temperature and sealed for use;

[0012] (2) Preparation of spinning core layer solution

[0013] Silk fibroin powder and medical grade polyvinyl alcohol were weighed and added to deionized water, and stirred in a 100℃ water bath until completely dissolved to obtain a core layer solution with a concentration of 10-30g / L silk fibroin solution and a concentration of 80-100g / L polyvinyl alcohol solution mixed;

[0014] (3) Preparation of spinning shell layer solution

[0015] The medical grade polylactic acid-glycolic acid copolymer is weighed and dissolved in a mixed solvent of chloroform and N,N-dimethylformamide, and stirred at room temperature until completely dissolved to obtain a shell solution of polylactic acid-glycolic acid copolymer with a concentration of 100-200 g / L;

[0016] The mixed solvent is uniformly mixed by chloroform and N,N-dimethylformamide in a volume ratio of (3-7):1;

[0017] (4) Preparation of core-shell structure nanofiber

[0018] The same volume of the shell solution and the core solution are measured and added into two injectors of a coaxial electrospinning device respectively, an aluminum foil collector is used for receiving, the positive electrode of a high-voltage power supply is connected to the coaxial spinning nozzle, and the negative electrode is connected to the aluminum foil collector which is well grounded, electrospinning is performed to obtain a core-shell structure nanofiber membrane material.

[0019] (5) Preparation of antibacterial coating

[0020] 5 g of the nanofiber membrane material is immersed in 100 mL of an antibacterial solution with a concentration of 0.1-0.5 g / L, and soaked at 25-35°C for 0.5-2 h; after taking out, it is first air-dried at room temperature, and then dried in a vacuum drying oven at 45°C for 24 h to obtain a degradable nanofiber membrane material with an antibacterial coating.

[0021] Further technical solutions are as follows:

[0022] In step (1), the dialysis time is 72 h, and the deionized water is replaced every 6 h during dialysis; the molecular weight cut-off Mw of the dialysis bag is 8-14 kDa.

[0023] In step (1), the freeze-drying conditions are: pre-freezing at -20°C for 12 h, freezing at -80°C for 12 h, and vacuum drying at -80°C for 10 h.

[0024] In step (2), the molecular weight of polyvinyl alcohol is 80-100 kDa.

[0025] In step (3), the molecular weight of polylactic acid-glycolic acid copolymer is 100-120 kDa, and the molar ratio of lactic acid to glycolic acid in the polylactic acid-glycolic acid copolymer is 75:25 or 80:20.

[0026] In step (4), during the coaxial electrospinning process, the voltage is 20-30 kV, the environmental humidity is 50±5%, the temperature of the core solution is controlled at 60°C, the flow rate of the core solution is 0.2-0.3 mL / h, the flow rate of the shell solution is 0.3-0.5 mL / h, the receiving distance is 15-20 cm, the inner and outer diameters of the inner needle of the coaxial spinning nozzle are 0.4 mm and 0.6 mm respectively, and the inner and outer diameters of the outer needle are 1.5 mm and 3 mm respectively.

[0027] In step (5), the bacteriostatic solution is prepared from natural plant bacteriostatic substances, the natural plant bacteriostatic substances are one of cinnamyl aldehyde, mannitol and curcumin, the natural plant bacteriostatic substances are dissolved in anhydrous ethanol to obtain the bacteriostatic solution with a concentration of 0.1-0.5 g / L.

[0028] Compared with the prior art, the beneficial technical effects of the present application are embodied in the following aspects:

[0029] (1) The sericin and the polyvinyl alcohol aqueous solution in the present application can quickly form a hydrogel under the condition of 60 DEG C, the morphology, stability and mechanical strength of the nanofiber are enhanced, water is used as the solvent, and no chemical crosslinking agent is needed, which is environmentally friendly and has no toxic side effects.

[0030] (2) The coaxial electrospinning technology is used in the present application to directly process the composite nanofiber membrane material with a core-shell structure in one step, the hydrogel property of the core layer material is utilized to realize the preparation of the composite fiber membrane material with a hydrophilic inner core and a hydrophobic shell, the porosity of the obtained fiber membrane material is 32%, the nanofiber surface is smooth and uniform, the diameter is 800-1300 nm, the inner diameter of the core layer is 250-350 nm, and the inner diameter of the shell layer is 500-650 nm.

[0031] (3) The nanofiber membrane material with a core-shell structure prepared in the present application can not only load the hydrophilic drugs by the core layer composite hydrogel, but also load the hydrophobic drugs which are difficult to be loaded by the hydrogel by utilizing the dispersion and solubilization of polyvinyl alcohol, and the slow degradation of the shell layer material polylactic acid-glycolic acid copolymer and the free diffusion of the drugs can realize the sustained release effect of the drugs, and the nanofiber membrane material has outstanding advantages in the biomedical fields such as wound dressings, hemostatic materials and drug release.

[0032] (4) The raw materials used in the present application have good biocompatibility and stability, the prepared nanofiber membrane material has good antibacterial effect and no cytotoxicity, and has a good release effect on the hydrophilic model protein bovine serum albumin; the preparation method provided by the present application is simple in operation, fast in preparation speed, good in continuity and uniformity. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a coaxial electrospinning device schematic diagram of the present application.

[0034] Figure 2 It is a scanning electron microscope graph of the core-shell structure nanofiber membrane prepared in example 1 of the present application.

[0035] Figure 3 It is a contact angle test graph of the core layer fiber, the shell layer fiber and the core-shell fiber in the nanofiber prepared in example 1 of the present application.

[0036] Figure 4 The drug release curve of the nanofiber membrane material prepared in Example 4 of the present application carrying bovine serum albumin. DETAILED DESCRIPTION

[0037] The present application will be further described in detail below with specific embodiments.

[0038] Example 1

[0039] The preparation steps of the degradable nanofiber membrane material with a hydrophilic inner core and a hydrophobic outer shell are as follows:

[0040] (1) Extraction of sericin

[0041] Take 20 g of silk and cut it into 1 cm 2 pieces, and place it in a 500 mL sodium carbonate solution with a concentration of 0.02 mol / L in a constant temperature water bath at 100°C for 1 h. Centrifuge the solution in a centrifuge tube at 3500 rpm for 10 min, remove the precipitate, and obtain a clear sericin solution. Pour the sericin solution into a dialysis bag (Mw: 8-14 kDa), and place it in deionized water under slow stirring at 4°C. Change the deionized water every 6 h, and dialyze for a total of 72 h. After dialysis, place it in a vacuum freeze dryer, and pre-freeze at -20°C for 12 h, freeze at -80°C for 12 h, and then vacuum dry at -80°C for 10 h to obtain sericin powder. Store it at -20°C and seal it for use.

[0042] (2) Preparation of spinning core layer solution

[0043] Take 20 g of sericin powder and 80 g of medical grade polyvinyl alcohol with a molecular weight of 90 kDa, and add them to 1 L of deionized water. Stir in a water bath at 100°C until completely dissolved to obtain a core layer solution mixed with a sericin solution with a concentration of 20 g / L and a polyvinyl alcohol solution with a concentration of 80 g / L.

[0044] (3) Preparation of spinning shell layer solution

[0045] Take 100 g of polylactic acid-glycolic acid copolymer (molar ratio of lactic acid to glycolic acid is 75:25) with a molecular weight of 120 kDa, and dissolve it in 800 mL of a mixed solvent of chloroform and 200 mL of N,N-dimethylformamide (volume ratio is 4:1). Stir at room temperature until completely dissolved to obtain a shell layer solution of polylactic acid-glycolic acid copolymer with a concentration of 100 g / L.

[0046] (4) Preparation of core-shell structure nanofiber

[0047] Reference Figure 120 mL of shell solution and 20 mL of core solution were measured and added to the two syringes of the coaxial electrospinning device, respectively. The voltage was set to 25 kV, the temperature of the core solution was controlled at 60 °C, the flow rate of the core solution was 0.2 mL / h, the flow rate of the shell solution was 0.3 mL / h, the receiving distance of the aluminum foil collector was 15 cm, the positive terminal of the high voltage power supply was connected to the coaxial spinning nozzle, and the negative terminal was connected to the grounded aluminum foil receiver. Electrospinning was performed to obtain core-shell structured nanofiber materials.

[0048] The inner and outer diameters of the inner needle of the coaxial spinning nozzle are 0.4 mm and 0.6 mm, respectively, while the inner and outer diameters of the outer needle are 1.5 mm and 3 mm, respectively.

[0049] (5) Preparation of antibacterial coating

[0050] Cinnamaldehyde was dissolved in anhydrous ethanol to prepare an antibacterial solution with a concentration of 0.1 g / L. 5 g of nanofiber membrane material was added to 100 mL of the antibacterial solution and soaked at 25 °C for 2 h. The solution was then filtered and removed. The membrane was first air-dried at room temperature and then dried in a vacuum drying oven at 45 °C for 24 h to obtain a biodegradable nanofiber membrane material with an antibacterial coating.

[0051] See Figure 2 Image (a) is a scanning electron microscope image of the nanofiber membrane prepared in Example 1. The nanofiber membrane has a porosity of 32%, a smooth and uniform fiber surface, no beaded or spindle structures, and a diameter of 800-1300 nm. See also Figure 2 Image (b) is a cross-sectional scanning electron microscope image of the nanofiber, showing the core-shell structure of the fiber. The inner diameter of the core layer is 250-350 nm, and the inner diameter of the shell layer is 500-650 nm.

[0052] See Figure 3 The contact angles of the core layer fibers, shell fibers, and core-shell fibers prepared in Example 1 were tested. The results showed that the core layer fibers were hydrophilic (contact angle < 90°), while the shell fibers were hydrophobic (contact angle > 90°). Since the shell is the outer layer of the core-shell structure nanofiber membrane, the core-shell fibers showed the same contact angle value as the shell fibers.

[0053] Example 2

[0054] The preparation steps of a biodegradable nanofiber membrane material with a hydrophilic core and a hydrophobic shell are as follows:

[0055] (1) Extraction of sericin

[0056] Weigh out 20g of silk and cut it into 1cm pieces. 2The silk fibroin fragments were placed in 500 mL of 0.05 mol / L sodium carbonate solution, and degumming was performed by boiling at 100°C in a constant-temperature water bath for 1 h. The solution was transferred into a centrifuge tube and centrifuged at 3500 rpm for 10 min, and the precipitate was removed to obtain a clear silk fibroin solution. The silk fibroin solution was poured into a dialysis bag (Mw: 8-14 kDa), and dialysis was performed in deionized water at 4°C with slow stirring, and the deionized water was replaced every 6 h, and the dialysis was performed for 72 h. After dialysis, the solution was placed in a vacuum freeze dryer, and pre-freezing was performed at -20°C for 12 h, freezing was performed at -80°C for 12 h, and vacuum drying was performed at -80°C for 10 h to obtain a silk fibroin powder, which was stored at -20°C.

[0057] (2) Preparation of a spinning core layer solution

[0058] 30 g of the silk fibroin powder and 90 g of medical-grade polyvinyl alcohol with a molecular weight of 100 kDa were weighed into 1 L of deionized water, and stirring was performed in a 100°C water bath until complete dissolution to obtain a core layer solution mixed with a silk fibroin solution with a concentration of 30 g / L and a polyvinyl alcohol solution with a concentration of 90 g / L.

[0059] (3) Preparation of a spinning shell layer solution

[0060] 150 g of polylactic acid-glycolic acid copolymer (molar ratio of lactic acid to glycolic acid is 75:25) with a molecular weight of 110 kDa was dissolved in a mixed solvent of 750 mL of chloroform and 250 mL of N,N-dimethylformamide (volume ratio is 3:1), and stirring was performed at room temperature until complete dissolution to obtain a shell layer solution of the polylactic acid-glycolic acid copolymer with a concentration of 150 g / L.

[0061] (4) Preparation of a core-shell structure nanofiber

[0062] Referring to Figure 1 , 20 mL of the shell layer solution and 20 mL of the core layer solution were measured and added into two syringes of a coaxial electrospinning device, the voltage was set to 20 kV, the temperature of the core layer solution was controlled to be 60°C, the flow rate of the core layer solution was 0.3 mL / h, the flow rate of the shell layer solution was 0.5 mL / h, the receiving distance of the aluminum foil collector was 20 cm, the positive electrode of the high-voltage power supply was connected to the coaxial spinning nozzle, and the negative electrode was connected to the aluminum foil receiver with good grounding treatment, electrospinning was performed, and a core-shell structure nanofiber material was obtained.

[0063] The inner and outer diameters of the inner needle of the coaxial spinning nozzle were 0.4 mm and 0.6 mm, respectively, and the inner and outer diameters of the outer needle were 1.5 mm and 3 mm, respectively.

[0064] (5) Preparation of an antibacterial coating

[0065] The mannitol is dissolved in anhydrous ethanol to prepare an antibacterial solution with a concentration of 0.2 g / L, 5 g of nanofiber membrane material is added to 100 mL of the antibacterial solution, soaked at 30°C for 1.5 h, and then filtered to obtain the product; the product is first dried at room temperature, and then dried in a vacuum drying box at 45°C for 24 h to obtain the degradable nanofiber membrane material with an antibacterial coating.

[0066] Example 3

[0067] The preparation steps of the degradable nanofiber membrane material with a hydrophilic inner core and a hydrophobic outer shell are as follows:

[0068] (1) Extraction of sericin

[0069] 20 g of silk is weighed and cut into 1 cm 2 pieces, and then placed in 500 mL of deionized water. Boiling degumming is performed in a constant temperature water bath at 100°C for 1 h. The solution is transferred into a centrifuge tube and centrifuged at 3500 rpm for 10 min. The precipitate is removed to obtain a clear sericin solution. The sericin solution is poured into a dialysis bag (Mw: 8-14 kDa) and placed in deionized water. Slow stirring is performed at 4°C, and the deionized water is replaced every 6 h. The dialysis is performed for a total of 72 h. After dialysis, the dialysis bag is placed in a vacuum freeze dryer. Pre-freezing is performed at -20°C for 12 h, freezing is performed at -80°C for 12 h, and vacuum drying is performed at -80°C for 10 h to obtain sericin powder. The sericin powder is sealed and stored at -20°C for later use.

[0070] (2) Preparation of spinning core layer solution

[0071] 10 g of sericin powder and 100 g of medical grade polyvinyl alcohol with a molecular weight of 80 kDa are weighed and added to 1 L of deionized water. The mixture is stirred in a water bath at 100°C until completely dissolved to obtain a core layer solution with a concentration of 10 g / L of sericin solution and 100 g / L of polyvinyl alcohol solution.

[0072] (3) Preparation of spinning shell layer solution

[0073] 200 g of polylactic acid-glycolic acid copolymer (molar ratio of lactic acid to glycolic acid is 80:20) with a molecular weight of 100 kDa is dissolved in a mixed solvent of 875 mL of chloroform and 125 mL of N,N-dimethylformamide (volume ratio is 7:1). The mixture is stirred at room temperature until completely dissolved to obtain a shell layer solution of polylactic acid-glycolic acid copolymer with a concentration of 200 g / L.

[0074] (4) Preparation of core-shell structure nanofiber

[0075] Reference Figure 1, 20 mL of the shell layer solution and 20 mL of the core layer solution were measured and added into two syringes of the coaxial electrospinning device, the voltage was set to 30 kV, the temperature of the core layer solution was controlled to 60 DEG C, the flow rate of the core layer solution was 0.25 mL / h, the flow rate of the shell layer solution was 0.4 mL / h, the receiving distance of the aluminum foil collector was 18 cm, the positive electrode of the high-voltage power supply was connected to the coaxial spinning nozzle, and the negative electrode was connected to the aluminum foil collector with good grounding treatment, electrospinning was performed, and a core-shell structure nanofiber material was obtained.

[0076] The inner and outer diameters of the inner needle in the coaxial spinning nozzle were 0.4 mm and 0.6 mm respectively, and the inner and outer diameters of the outer needle were 1.5 mm and 3 mm respectively.

[0077] (5) Preparation of bacteriostatic coating

[0078] Curcumin was dissolved in anhydrous ethanol to prepare a bacteriostatic solution with a concentration of 0.5 g / L, 5 g of nanofiber membrane material was added into 100 mL of the bacteriostatic solution, soaked at 35 DEG C for 0.5 h, and then filtered and taken out; first, air-dried at room temperature, and then dried in a vacuum drying box at 45 DEG C for 24 h to obtain a degradable nanofiber membrane material with a bacteriostatic coating.

[0079] Example 4

[0080] The preparation steps of the drug-loaded nanofiber were the same as those in Example 1, except that in step (2), bovine serum albumin powder was added at room temperature to prepare a mixed core layer solution containing bovine serum albumin with a concentration of 1 g / L.

[0081] Performance test

[0082] 1. Bacteriostatic property test:

[0083] The bacteriostatic effect of the nanofiber membrane materials prepared in Examples 1-3 on three kinds of bacteria (Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) was studied by filter paper piece experiment.

[0084] 100 μL of bacterial solution was uniformly coated on the surface of the culture medium, and a sterile forceps was used to clamp the sterilized 6 mm filter paper piece on the corresponding culture medium; 10 mg of nanofiber membrane material was uniformly dispersed on the filter paper piece, and acetone was used as a control, and then the mixture was allowed to stand for 10 min and placed in a culture box for incubation at 37 DEG C for 24 h. Three parallel groups were prepared, and the diameters of the bacteriostatic rings were measured by using a vernier caliper, and the test results were recorded in Table 1.

[0085] Table 1

[0086] Sample Staphylococcus aureus Escherichia coli Pseudomonas aeruginosa Example 1 12.42 ± 0.18 mm 11.53 ± 0.06 mm 11.73 ± 0.21 mm Example 2 11.58 ± 0.14 mm 11.40 ± 0.23 mm 11.54 ± 0.16 mm Example 3 11.75 ± 0.10 mm 11.45 ± 0.14 mm 11.68 ± 0.09 mm Control 6.56 ± 0.08 mm 6.44 ± 0.15 mm 6.38 ± 0.24 mm

[0087] As shown by the test results in Table 1, the degradable nanofiber membrane material with a hydrophilic core and a hydrophobic shell prepared in the application has good bacteriostatic effect.

[0088] 2. In vitro cytotoxicity test:

[0089] The in vitro cytotoxicity of the nanofiber membrane material prepared in Examples 1-3 was studied by XTT method.

[0090] Preparation of sample extract: the nanofiber membrane material prepared in Examples 1-3 was weighed, the extraction ratio was 0.2 g / mL, the extraction liquid was 10% fetal bovine serum cell culture medium, and was placed in a 37℃ extraction for 24 h; the blank control solution was 10% fetal bovine serum cell culture medium, the negative control solution was high-density polyethylene extract, and the positive control solution was 5% dimethyl sulfoxide.

[0091] In each well of a 96-well plate, 100 μL of a mouse fibroblast cell suspension with a density of 1×10 4 The cells were incubated in a 37℃ CO2 incubator for 24 h; after the cells adhered, the original culture medium was discarded, 100 μL of blank control solution, negative control solution, positive control solution and sample extract were added to each well, respectively, 6 wells for each group, and was continued to be cultured in the incubator for 72 h; 50 μL of XTT solution was added to each well, and after being continued to be cultured for 4 h, the absorbance was measured on an enzyme marker using 450 nm wavelength, the relative proliferation degree was calculated, and the test results were recorded in Table 2.

[0092] Table 2

[0093] Sample Relative degree of proliferation Example 1 98% Example 2 97% Example 3 97%

[0094] As can be seen from the test results in Table 2, the prepared degradable nanofiber material with a hydrophilic inner core and a hydrophobic shell has good biocompatibility (≥97% of the relative proliferation degree of cells) and no cytotoxicity.

[0095] 3. Bovine serum albumin drug release effect test:

[0096] 20 mg of the drug-loaded nanofiber membrane material prepared in Example 4 was loaded into a vial containing 2 mL of phosphate buffer solution with pH = 7.4, and the operation was repeated three times; the vial was placed in a 37℃ horizontal constant temperature shaking incubator (frequency 60 r / min); every 1 hour, 2 ml of the phosphate buffer solution was taken out, and new phosphate buffer solution was replaced; the concentration of bovine serum albumin in the taken-out phosphate buffer solution was determined by bicinchoninic acid (BCA) protein concentration determination kit, the absorbance at 562 nm was determined by ultraviolet spectrophotometer, and the bovine serum albumin content in the solution was calculated according to the standard curve. The release curve is shown in Figure 4It can be seen that the release behavior of bovine serum albumin presents a slow and uniform release trend in the previous week, and the cumulative release rate reaches 87.7%, and the release is completed in about two weeks, and the released drug amount reaches 95.5% of the drug loading amount. The results show that the prepared degradable nanofiber membrane material has a good slow release effect on the hydrophilic drug bovine serum albumin. As a model protein, the release behavior of bovine serum albumin in the core-shell nanofiber has a guiding significance for the release of other protein substances such as growth factors, enzymes, polypeptide substances and the like.

[0097] Those skilled in the art will readily understand that the above embodiments 1-3 are only preferred embodiments of the present application and are not intended to limit the present application, and any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a biodegradable nanofiber membrane material having a hydrophilic core and a hydrophobic shell, characterized in that: The biodegradable nanofiber membrane material has a core-shell structure, with the core layer being a hydrophilic sericin and polyvinyl alcohol composite hydrogel, and the shell layer being a hydrophobic polylactic acid-glycolic acid copolymer with good biocompatibility and biodegradability. The biodegradable nanofiber membrane material has a porosity of 32%, and the nanofibers have a smooth and uniform surface with a diameter of 800-1300 nm, a core inner diameter of 250-350 nm, and a shell inner diameter of 500-650 nm. The antibacterial solution is prepared from natural plant-based antibacterial substances, which are one of cinnamaldehyde, mannitol, and curcumin. The natural plant-based antibacterial substances are dissolved in anhydrous ethanol to obtain an antibacterial solution with a concentration of 0.1 ~ 0.5 g / L. The biodegradable nanofiber membrane material has good antibacterial effect and biocompatibility, and is suitable for wound dressings, hemostatic materials, and drug sustained-release materials; The preparation method of the biodegradable nanofiber membrane material is as follows: (1) Extraction of sericin; Cut 20g of silk into pieces and place them in 500mL of sodium carbonate solution or deionized water with a concentration of 0.02~0.05mol / L. Boil at 100℃ for 1 hour to degumme the silk, centrifuge to remove the precipitate, and obtain a clear sericin solution. Pour the sericin solution into a dialysis bag and dialyze it in deionized water. Freeze-dry under vacuum to obtain sericin powder, and store it in a sealed container at low temperature for later use. (2) Preparation of spinning core layer solution; Weigh out sericin powder and medical-grade polyvinyl alcohol and add them to deionized water. Stir in a 100°C water bath until completely dissolved to obtain a core layer solution consisting of a sericin solution with a concentration of 10-30 g / L and a polyvinyl alcohol solution with a concentration of 80-100 g / L. (3) Preparation of spinning shell solution; Medical-grade polylactic acid-glycolic acid copolymer was weighed and dissolved in a mixed solvent of chloroform and N,N-dimethylformamide. The solution was stirred at room temperature until completely dissolved to obtain a shell solution of polylactic acid-glycolic acid copolymer with a concentration of 100-200 g / L. The mixed solvent was prepared by uniformly mixing chloroform and N,N-dimethylformamide at a volume ratio of (3-7):

1. (4) Preparation of core-shell structured nanofibers; Equal volumes of shell and core solutions were measured and added to two syringes of a coaxial electrospinning device. The solutions were collected by an aluminum foil collector. The positive terminal of the high-voltage power supply was connected to the coaxial spinning nozzle, and the negative terminal was connected to the grounded aluminum foil collector. Electrospinning was then performed to obtain a core-shell structured nanofiber membrane material. In step (4), the coaxial electrospinning process is carried out under the following conditions: voltage is 20 ~ 30kV, ambient humidity is 50± 5%, core layer solution temperature is controlled at 60℃, core layer solution flow rate is 0.2 ~ 0.3mL / h, shell layer solution flow rate is 0.3 ~ 0.5mL / h, receiving distance is 15 ~ 20cm, inner and outer diameters of the inner needle of the coaxial spinning nozzle are 0.4mm and 0.6mm respectively, and outer needle inner and outer diameters are 1.5mm and 3mm respectively. (5) Preparation of antibacterial coating; Immerse 5g of nanofiber membrane material in 100mL of antibacterial solution with a concentration of 0.1~0.5g / L and soak at 25~35℃ for 0.5~2h; remove, air dry at room temperature, and then dry in a vacuum drying oven at 45℃ for 24h to obtain a biodegradable nanofiber membrane material with an antibacterial coating.

2. The method for preparing a biodegradable nanofiber membrane material with a hydrophilic core and a hydrophobic shell according to claim 1, characterized in that: In step (1), the dialysis time is 72 hours, and the deionized water is replaced every 6 hours during the dialysis period; the molecular weight cutoff Mw of the dialysis bag is 8 ~ 14 kDa.

3. The method for preparing a biodegradable nanofiber membrane material with a hydrophilic core and a hydrophobic shell according to claim 1, characterized in that: In step (1), the freeze-drying conditions are: first, pre-freeze at -20℃ for 12 hours, freeze at -80℃ for 12 hours, and then vacuum dry at -80℃ for 10 hours.

4. The method for preparing a biodegradable nanofiber membrane material with a hydrophilic core and a hydrophobic shell according to claim 1, characterized in that: In step (2), the molecular weight of polyvinyl alcohol is 80 ~ 100 kDa.

5. The method for preparing a biodegradable nanofiber membrane material with a hydrophilic core and a hydrophobic shell according to claim 1, characterized in that: In step (3), the molecular weight of the polylactic acid-glycolic acid copolymer is 100 ~ 120 kDa, and the molar ratio of lactic acid to glycolic acid in the polylactic acid-glycolic acid copolymer is 75:25 or 80:20.

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