Lactic acid polymer three-dimensional fiber membrane as well as preparation method and application thereof

Abstract

The invention relates to the field of high polymer materials, and discloses a lactic acid polymer three-dimensional fiber membrane as well as a preparation method and application thereof. The fiber membrane has a diffraction peak when 2theta is equal to 11-13 degrees through XRD (X-Ray Diffraction) measurement, the half-peak width of the diffraction peak is 0.5-1.5 degrees, and the diffraction peak belongs to a stereocomplex crystal (110) SC. The three-dimensional fiber membrane has a three-dimensional composite structure and can regulate and control molecular chain conformation, so that the lactic acid copolymer three-dimensional composite fiber membrane has excellent biodegradability and also has excellent piezoelectric property and mechanical property.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, specifically to a three-dimensional fiber membrane made of lactic acid polymer, its preparation method, and its application. Background Technology

[0002] Bioelectricity is an important physiological activity in the human body. Electrical signals can not only regulate cell growth, proliferation, and differentiation, but also further influence nerve conduction, muscle contraction, embryonic development, and tissue regeneration. Therefore, using exogenous electrical stimulation for disease treatment is a highly promising medical approach. Since using external power sources for electrical stimulation cannot meet the needs of personalized medicine, piezoelectric materials, with their unique mechanoelectric conversion capabilities, offer a new approach to using electrical stimulation for disease treatment.

[0003] Piezoelectric materials can generate microcurrents under stress, transmitting electrical stimulation to cells or damaged tissues without an external power source, making them valuable in the biomedical field. However, biopiezoelectric materials currently face a significant material science bottleneck: the inability to simultaneously possess strong piezoelectricity and biodegradability. Strongly piezoelectric bioceramics like barium titanate (BaTiO3) are non-degradable and typically require secondary surgery for removal; degradable piezoelectric materials such as collagen, cellulose, and polylactic acid exhibit poor piezoelectricity, resulting in insufficient tissue regeneration promotion capabilities. Therefore, there is an urgent need to develop a biopiezoelectric material that combines strong piezoelectricity with biodegradability. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing biopiezoelectric materials, which cannot simultaneously possess strong piezoelectricity and biodegradability. This invention provides a lactic acid copolymer stereocomposite fiber membrane, its preparation method, and its applications. XRD analysis of this lactic acid copolymer stereocomposite fiber membrane revealed diffraction peaks at 2θ = 11-13°, with a half-width at half-maximum (FWHM) of 0.5-1.5°, demonstrating that the fiber membrane possesses a stereocomposite structure capable of regulating molecular chain conformation. This allows the lactic acid copolymer stereocomposite fiber membrane to exhibit excellent biodegradability while also possessing superior piezoelectric and mechanical properties.

[0005] To achieve the above objectives, the first aspect of the present invention provides a stereopolymer fiber membrane of lactic acid copolymer, wherein the fiber membrane exhibits diffraction peaks at 2θ = 11-13° as measured by XRD, the half-width at half-maximum (FWHM) of the diffraction peaks is 0.5-1.5°, and the diffraction peaks are attributed to stereopolymer composite crystals (110). SC .

[0006] A second aspect of the present invention provides a method for preparing a lactic acid copolymer stereocomposite fiber membrane, the method comprising:

[0007] S1. In the presence of water-soluble polymer materials and solvents, L-lactic acid copolymer and D-lactic acid copolymer are mixed evenly to obtain a mixed solution;

[0008] S2. Electrospin the mixed solution to obtain an electrospun membrane;

[0009] S3. The electrospun membrane is post-treated, dried and cooled to obtain a three-dimensional composite fiber membrane.

[0010] A third aspect of the present invention provides a lactic acid copolymer stereocomposite fiber membrane prepared by the method described in the second aspect of the present invention.

[0011] The fourth aspect of this invention provides an application of the lactic acid copolymer stereocomposite fiber membrane described in the first or third aspect in the fields of biosensing, tissue engineering, and drug delivery.

[0012] Through the above technical solution, the lactic acid copolymer stereocomposite fiber membrane, its preparation method, and its application provided by the present invention achieve the following beneficial effects: the lactic acid copolymer stereocomposite fiber membrane was found to have diffraction peaks at 2θ = 11-13° by XRD, and the half-width of the diffraction peaks was 0.5-1.5°, proving that the fiber membrane has stereocomposite effects. Stereocomposite effects can regulate the conformation of molecular chains, so that the lactic acid copolymer stereocomposite fiber membrane has excellent biodegradability, as well as excellent piezoelectric and mechanical properties. Attached Figure Description

[0013] Figure 1 This is a scanning electron microscope (SEM) image of the lactic acid copolymer stereocomposite fiber membrane prepared in Example 1;

[0014] Figure 2 This is the XRD pattern of the lactic acid copolymer stereocomposite fiber membrane prepared in Example 1. Detailed Implementation

[0015] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0016] In this invention, all apertures mentioned are average apertures.

[0017] The first aspect of this invention provides a stereopolymer fiber membrane of lactic acid, wherein XRD analysis shows diffraction peaks at 2θ = 11-13°, the half-width at half-maximum (WHM) of the diffraction peaks being 0.5-1.5°, and the diffraction peaks being attributed to stereopolymer (110). SC .

[0018] In this invention, the presence of diffraction peaks at 2θ = 11-13° as measured by XRD proves that the fiber membrane has a three-dimensional composite structure, which gives the lactic acid polymer three-dimensional composite fiber membrane excellent piezoelectric properties.

[0019] According to the present invention, in the fiber membrane, the fibers forming the fiber membrane have a micron-scale pore structure between the fibers and the fiber surfaces of the fibers forming the fiber membrane have a nano-scale pore structure.

[0020] In this invention, the fiber membrane contains, for example... Figure 1 As shown, the "between fibers" refers to the micron-sized pore structure within the blue circle, and the "fiber surface" refers to the nano-sized pore structure within the red circle.

[0021] According to one embodiment of the present invention, the pore size of the pore structure between the fibers forming the fiber membrane is 1-30 micrometers.

[0022] According to one embodiment of the present invention, the pore size of the pore structure on the fiber surface forming the fiber membrane is 10-400 nanometers.

[0023] In this invention, the pore structure between the fiber membranes is obtained statistically from SEM images.

[0024] In this invention, the aperture refers to the average size of the aperture structure in all directions.

[0025] In this invention, the inventors, through extensive research, discovered that, from a microstructural perspective, the pores formed between different fibers in the fiber membrane are micrometer-scale pore structures, while the surface of each individual fiber has a nanometer-scale pore structure. When the three-dimensional composite fiber membrane simultaneously possesses these multi-level pores, it can significantly improve the piezoelectric properties of the three-dimensional composite fiber membrane, and also enhance its biodegradability.

[0026] According to the present invention, the polymers forming the fiber membrane include L-lactic acid copolymers and D-lactic acid copolymers.

[0027] In this invention, the coexistence of the L-lactic acid copolymer and the D-lactic acid copolymer can form a stereocomplex structure, thereby improving the piezoelectricity of the stereocomplex.

[0028] According to the present invention, the L-lactic acid copolymer has an ABA structure, wherein segment A is a L-polylactic acid segment, and segment B is selected from at least one of polypolyol segments, polyester segments, polyvinyl alcohol segments, and polyglycolic acid.

[0029] In one specific embodiment of the present invention, in the L-lactic acid copolymer having an ABA structure, the molar ratio of segment A to segment B is 2:1.

[0030] In this invention, in the L-lactic acid copolymer with the ABA structure, the degree of polymerization of segment A is 100-2000, and the degree of polymerization of segment B is 10-1000.

[0031] According to the present invention, the dextrorotatory lactic acid copolymer has a CDC structure, wherein segment C is a dextrorotatory polylactic acid segment, and segment D is selected from at least one of polypolyol segments, polyester segments, polyvinyl alcohol segments, and polyglycolic acid.

[0032] In this invention, when the dextrorotatory lactic acid copolymer has a CDC structure, and is combined with the aforementioned levorotatory lactic acid copolymer having an ABA structure, the resulting fiber membrane can simultaneously have a stereocomposite effect, further improving its piezoelectricity and exhibiting good mechanical strength.

[0033] In one specific embodiment of the present invention, in the dextrorotatory lactic acid copolymer having a CDC structure, the molar ratio of segment C to segment D is 2:1.

[0034] In this invention, in the dextrorotatory lactic acid copolymer with the CDC structure, the degree of polymerization of segment C is 100-2000, and the degree of polymerization of segment D is 10-1000.

[0035] According to the present invention, the polypolyol in the polypolyol segment is selected from at least one of polyethylene glycol, polypropylene glycol and polybutanediol.

[0036] According to the present invention, the polyester in the polyester segment is selected from at least one of polycaprolactone, polybutylene succinate, and polyhydroxyalkanoates.

[0037] In this invention, when the L-lactic acid copolymer and the D-lactic acid copolymer contain at least one of polyol segments, polyester segments, polyvinyl alcohol segments and polyhydroxyacetic acid, the properties of the obtained stereocomposite fiber membrane can be effectively regulated, such as improving the hydrophilicity, biodegradability and biocompatibility of the fiber membrane.

[0038] According to the present invention, the molar ratio of the L-lactic acid copolymer and the D-lactic acid copolymer is 1:0.1-10.

[0039] In this invention, the molar ratio of the L-lactic acid copolymer and the D-lactic acid copolymer satisfies the above-mentioned range, which can further improve the piezoelectricity of the material.

[0040] Furthermore, the molar ratio of the L-lactic acid copolymer and the D-lactic acid copolymer is 1:0.5-2.

[0041] According to the present invention, the number average molecular weight of the polymer forming the fiber membrane is ≥20,000 g / mol, preferably ≥50,000 g / mol.

[0042] In this invention, the polymers refer to L-lactic acid copolymers and D-lactic acid copolymers, that is, the number average molecular weight of the L-lactic acid copolymer is ≥20,000 g / mol, preferably ≥50,000 g / mol, and the number average molecular weight of the D-lactic acid copolymer is ≥20,000 g / mol, preferably ≥50,000 g / mol.

[0043] A second aspect of the present invention provides a method for preparing a lactic acid copolymer stereocomposite fiber membrane, the method comprising:

[0044] S1. In the presence of water-soluble polymer materials and solvents, L-lactic acid copolymer and D-lactic acid copolymer are mixed evenly to obtain a mixed solution;

[0045] S2. Electrospin the mixed solution to obtain an electrospun membrane;

[0046] S3. The electrospun membrane is post-treated, dried and cooled to obtain a three-dimensional composite fiber membrane.

[0047] In this invention, the presence of water-soluble polymer materials and solvents can endow the final fiber membrane with a multi-level porous structure, thereby improving the deformation ability of the fiber membrane, significantly enhancing its piezoelectricity, and improving the degradation performance of the obtained stereocomposite fiber membrane.

[0048] In this invention, the L-lactic acid copolymer and the D-lactic acid copolymer can completely form a three-dimensional composite structure.

[0049] According to the present invention, the L-lactic acid copolymer has an ABA structure, wherein segment A is a L-polylactic acid segment, and segment B is selected from at least one of polypolyol segments, polyester segments, polyvinyl alcohol segments, and polyglycolic acid.

[0050] According to the present invention, the dextrorotatory lactic acid copolymer has a CDC structure, wherein segment C is a dextrorotatory polylactic acid segment, and segment D is selected from at least one of polypolyol segments, polyester segments, polyvinyl alcohol segments, and polyglycolic acid.

[0051] In this invention, when the L-lactic acid copolymer has an ABA structure and the D-lactic acid copolymer has a CDC structure, it is possible to simultaneously ensure that the obtained fiber membrane has a three-dimensional composite structure, further improve its piezoelectricity, and have good mechanical strength.

[0052] In this invention, when the L-lactic acid copolymer and the D-lactic acid copolymer contain at least one of polyol segments, polyester segments, polyvinyl alcohol segments and polyhydroxyacetic acid, the properties of the obtained stereocomposite fiber membrane can be effectively regulated, such as improving the hydrophilicity, biodegradability and biocompatibility of the fiber membrane.

[0053] According to the present invention, the polypolyol in the polypolyol segment is selected from at least one of polyethylene glycol, polypropylene glycol and polybutanediol.

[0054] According to the present invention, the polyester in the polyester segment is selected from at least one of polycaprolactone, polybutylene succinate, and polyhydroxyalkanoates.

[0055] According to one embodiment of the present invention, the number-average molecular weight of the L-lactic acid copolymer is ≥20,000 g / mol, preferably ≥50,000 g / mol.

[0056] According to one embodiment of the present invention, the number-average molecular weight of the dextrorotatory lactic acid copolymer is ≥20,000 g / mol, preferably ≥50,000 g / mol.

[0057] In this invention, the molar ratio of segment A to segment B in the L-lactic acid copolymer having an ABA structure is 2:1.

[0058] In this invention, in the L-lactic acid copolymer with the ABA structure, the degree of polymerization of segment A is 100-2000, and the degree of polymerization of segment B is 10-1000.

[0059] In this invention, the molar ratio of segment C to segment D in the dextrorotatory lactic acid copolymer with the CDC structure is 2:1.

[0060] In this invention, in the dextrorotatory lactic acid copolymer with the CDC structure, the degree of polymerization of segment C is 100-2000, and the degree of polymerization of segment D is 10-1000.

[0061] According to the present invention, the molar ratio of the L-lactic acid copolymer and the D-lactic acid copolymer is 1:0.1-10, preferably 1:0.5-2.

[0062] According to the present invention, the water-soluble polymer material is a natural water-soluble polymer material and / or a synthetic water-soluble polymer material.

[0063] In this invention, the number-average molecular weight of the water-soluble polymer material is 2-1,000,000 g / mol, preferably 200,000-400,000 g / mol.

[0064] According to a preferred embodiment of the present invention, the water-soluble polymer material is selected from at least one of polyethylene glycol, polyvinylpyrrolidone, and carboxymethyl cellulose.

[0065] According to the present invention, based on the total mass of the L-lactic acid copolymer, the D-lactic acid copolymer and the water-soluble polymer material, the amount of the water-soluble polymer material is 5-60 wt%.

[0066] Furthermore, based on the total mass of the L-lactic acid copolymer, the D-lactic acid copolymer, and the water-soluble polymer material, the amount of the water-soluble polymer material is 30-50 wt%.

[0067] In this invention, the amount of the water-soluble polymer material meets the above-mentioned range, which can form nanoscale pores on the fiber surface and improve the piezoelectricity of the three-dimensional composite fiber membrane.

[0068] According to the present invention, the solvent is selected from at least one of chloroform, dichloromethane, and N,N-dimethylformamide.

[0069] In this invention, the type of solvent is not particularly limited. For example, the solvent used in this invention is chloroform.

[0070] According to the present invention, the concentration of the mixed solution is 3-20 wt%.

[0071] In this invention, the concentration of the mixed solution can be adjusted by changing the amount of solvent so that the L-lactic acid copolymer, D-lactic acid copolymer, and water-soluble polymeric material account for 3-20 wt% of the mixed solution.

[0072] Furthermore, the concentration of the mixed solution is 6-15 wt%.

[0073] According to the present invention, the conditions for electrospinning include: needle diameter of 18-26G, voltage of 10-25kV, distance from needle tip to substrate of 5-20cm, and liquid dispensing speed of 1-5mL / h.

[0074] In this invention, the inventors discovered that by controlling the conditions of electrospinning to meet the above-mentioned range, the prepared three-dimensional composite fiber membrane can have multi-level pores, enhance piezoelectric properties, and at the same time ensure its good biodegradability.

[0075] According to the present invention, the post-treatment conditions include: immersing the electrospun membrane in deionized water for 6-24 hours at a temperature of 25-75°C.

[0076] In this invention, the post-treatment conditions meet the above-mentioned range, which can remove water-soluble polymer materials and obtain a fiber membrane with a multi-level porous structure. At the same time, the diameter of the fibers forming the fiber membrane is suitable, so that the three-dimensional composite fiber membrane has a more suitable degradation time.

[0077] In this invention, during post-processing, it is preferable to soak and shake the electrospun membrane in deionized water.

[0078] Furthermore, the post-treatment conditions include: immersing the electrospun membrane in deionized water for 12-24 hours at a temperature of 50-75°C.

[0079] According to one embodiment of the present invention, the diameter of the fibers forming the fiber membrane is 100-1000 nm, preferably 340-410 nm.

[0080] According to the present invention, the drying conditions include: a temperature of 80-160°C and a drying time of 0.5-6 hours.

[0081] According to a particularly preferred embodiment of the present invention, the method includes:

[0082] S1. In the presence of water-soluble polymer materials and solvents, L-lactic acid copolymer and D-lactic acid copolymer are mixed evenly to obtain a mixed solution;

[0083] S2. Load the mixed solution into a syringe and connect it to a 22G needle for electrospinning. The electrospinning voltage is 20-25kV, the distance from the needle tip to the substrate is 15-20cm, and the liquid pushing speed is 1-3mL / h to obtain an electrospinned membrane.

[0084] S3. The electrospun membrane is placed in deionized water at 50-70℃ and shaken for 10-12 hours for post-treatment. Then it is placed in an oven at 120-140℃ for 1-3 hours and cooled to obtain a three-dimensional composite fiber membrane.

[0085] The molar ratio of L-lactic acid copolymer to D-lactic acid copolymer is 1:0.5-2, and the amount of water-soluble polymer material is 30-50 wt%.

[0086] A third aspect of the present invention provides a lactic acid copolymer stereocomposite fiber membrane prepared by the method described in the second aspect of the present invention.

[0087] In this invention, the properties and structure of the lactic acid copolymer stereocomposite fiber membrane are consistent with those of the lactic acid copolymer stereocomposite fiber membrane described in the first aspect of this invention, and will not be repeated here.

[0088] In this invention, the fiber diameter of the fiber forming the lactic acid copolymer stereocomposite fiber membrane is 100-1000 nm, preferably 340-410 nm; the open circuit voltage is 6-25 V, preferably 20-25 V; the elastic modulus is 410-650 kPa, preferably 550-580 kPa; and the degradation time is 7-15 weeks, preferably 10-12 weeks.

[0089] The fourth aspect of the present invention provides an application of the lactic acid copolymer stereocomposite fiber membrane described in the first or third aspect in at least one of the fields of biosensing, tissue engineering, and drug delivery.

[0090] The present invention will be described in detail below through embodiments.

[0091] In the following embodiments, the pore structure on the fiber surface and the pore structure between fibers were confirmed by scanning electron microscopy (SEM);

[0092] The molar ratio of L-lactic acid copolymer to D-lactic acid copolymer is calculated based on the amount of feed.

[0093] Fiber diameter was obtained by statistical analysis of SEM images;

[0094] The open-circuit voltage was tested by the following method: the fiber membrane was fixed on the base of the piezoelectric measuring instrument, and copper electrodes were attached to the surface. The copper electrodes were connected to a voltage amplifier. The fiber membrane was pulsed with an iron sheet at a frequency of 2 times / second. At the same time, the voltage change was recorded by the voltage amplifier to obtain the open-circuit voltage.

[0095] The modulus of elasticity was measured using a universal tensile testing machine.

[0096] The degradation time was determined by the following method: the electrospun membrane was placed in phosphate buffer and then placed on a shaker. The membrane was observed every 7 days. The time required for the fiber membrane to degrade by 50 wt% was the degradation time.

[0097] PEG300k, molecular weight 300,000 g / mol, purchased from Adamas-beta.

[0098] PLLA-PEG-PLLA was synthesized in-house using the following method:

[0099] 4 g of PEG (number average molecular weight 20000 g / mol) was added to the reaction flask and heated at 100 °C under vacuum for 2 h to remove water and impurities. 0.2 mL of a toluene solution of stannous isooctanoate (100 mg / mL) was added to the reaction flask (catalyst effective mass 20 mg), and the mixture was heated at 100 °C under vacuum for 15 min to remove toluene and impurities. 15 g of L-lactide was added to the reaction flask, and the polymerization reaction was carried out at 130 °C for 4 h. The resulting product was analyzed by 1H NMR spectroscopy and identified as PLLA-PEG-PLLA. The number average molecular weight was 100000 g / mol. The degree of polymerization of the PLLA segment was 556, and that of the PEG segment was 455.

[0100] PDLA-PEG-PDLA was synthesized in-house using the following method:

[0101] 4 g of PEG (number average molecular weight 20000 g / mol) was added to the reaction flask and heated at 100 °C under vacuum for 2 h to remove water and impurities. 0.2 mL of a toluene solution of stannous isooctanoate (100 mg / mL) was added to the reaction flask (catalyst effective mass 20 mg), and the mixture was heated at 100 °C under vacuum for 15 min to remove toluene and impurities. 15 g of D-lactide was added to the reaction flask, and the polymerization reaction was carried out at 130 °C for 4 h. The obtained product was analyzed by 1H NMR spectroscopy and identified as PDLA-PEG-PDLA. The number average molecular weight was 100000 g / mol. The degree of polymerization of the PDLA segment was 556, and the degree of polymerization of the PEG segment was 455.

[0102] In the following examples, PLLA refers to polylactic acid (PLLA) and PDLA refers to polylactic acid (PDLA).

[0103] Example 1

[0104] S1. Dissolve 0.54g of PLLA-PEG-PLLA, 0.54g of PDLA-PEG-PDLA and 0.72g of PEG300k in 28.2g of chloroform to obtain a mixed solution with a concentration of 6wt%.

[0105] S2. Load the mixed solution into a syringe and connect it to a 22G needle for electrospinning. The electrospinning voltage is 20kV, the distance from the needle tip to the substrate is 10cm, and the liquid pushing speed is 2mL / h to obtain an electrospinned membrane.

[0106] S3. The electrospun membrane was placed in deionized water at 60°C and shaken for 12 hours for post-treatment. Then it was placed in an oven at 140°C for 1 hour and cooled to obtain a three-dimensional fiber membrane A1.

[0107] The molar ratio of PLLA-PEG-PLLA and PDLA-PEG-PDLA is 1:1, and the amount of PEG300k is 40wt%, based on the total mass of PLLA-PEG-PLLA, PDLA-PEG-PDLA and PEG300k.

[0108] The prepared three-dimensional fiber membrane A1 was subjected to X-ray diffraction testing, and the results are shown in the figure. Figure 2 , Figure 2 In the sample, a diffraction peak exists at 2θ = 12°, and the half-width of the diffraction peak is 1°. The diffraction peak belongs to the stereocomplex crystal (110). SC This proves that the fiber membrane has a three-dimensional composite structure.

[0109] The pore size of the pore structure between the fiber membranes is 4.8 micrometers, and the pore size of the pore structure on the surface of the fiber membrane is 132 nanometers.

[0110] Example 2

[0111] The procedure was carried out according to Example 1, except that in step S3, the electrospun membrane was placed in deionized water at 25°C and shaken for 12 hours, and then placed in an oven at 100°C for 1 hour. A three-dimensional fiber membrane A2 was thus obtained.

[0112] The pore size of the pore structure between the fiber membranes is 6 micrometers, and the pore size of the pore structure on the surface of the fiber membrane is 71 nanometers.

[0113] Example 3

[0114] The procedure was carried out according to Example 1, except that in step S1, 0.9 g of PLLA-PEG-PLLA, 0.18 g of PDLA-PEG-PDLA, and 0.72 g of PEG300k were dissolved in 28.2 g of chloroform to obtain a mixed solution (concentration of 6 wt%). A three-dimensional fiber membrane A3 was then prepared.

[0115] The molar ratio of PLLA-PEG-PLLA and PDLA-PEG-PDLA is 1:0.2, and the amount of PEG300k is 40wt%, based on the total mass of PLLA-PEG-PLLA, PDLA-PEG-PDLA and PEG300k.

[0116] The pore size of the pore structure between the fiber membranes is 4.7 micrometers, and the pore size of the pore structure on the surface of the fiber membrane is 128 nanometers.

[0117] Example 4

[0118] The procedure was carried out according to Example 1, except that in step S1, 0.81 g of PLLA-PEG-PLLA, 0.81 g of PDLA-PEG-PDLA, and 0.18 g of PEG300k were dissolved in 28.2 g of chloroform to obtain a mixed solution (concentration of 6 wt%). A three-dimensional fiber membrane A4 was then prepared.

[0119] The molar ratio of PLLA-PEG-PLLA and PDLA-PEG-PDLA is 1:1, and the amount of PEG300k is 10wt%, based on the total mass of PLLA-PEG-PLLA, PDLA-PEG-PDLA and PEG300k.

[0120] The pore size of the pore structure between the fiber membranes is 3.7 micrometers, and the pore size of the pore structure on the surface of the fiber membrane is 53 nanometers.

[0121] Example 5

[0122] The procedure was carried out according to Example 1, except that in step S1, 0.54 g of PLLA-PVA-PLLA, 0.54 g of PDLA-PVA-PDLA, and 0.72 g of PEG300k were dissolved in 28.2 g of chloroform to obtain a mixed solution (concentration of 6 wt%). A three-dimensional fiber membrane A5 was then prepared.

[0123] The molar ratio of PLLA-PEG-PLLA and PDLA-PEG-PDLA is 1:1, and the amount of PEG300k is 40wt%, based on the total mass of PLLA-PEG-PLLA, PDLA-PEG-PDLA and PEG300k.

[0124] The pore size of the pore structure between the fiber membranes is 5.1 micrometers, and the pore size of the pore structure on the surface of the fiber membrane is 135 nanometers.

[0125] Example 6

[0126] The method was carried out according to Example 1, except that in step (1), 0.54 g of PLLA-PEG-PLLA, 0.54 g of PDLA-PEG-PDLA and 0.72 g of carboxymethyl cellulose were dissolved in 28.2 g of chloroform to obtain a mixed solution (concentration of 6 wt%). A three-dimensional fiber membrane A6 was then prepared.

[0127] The molar ratio of PLLA-PEG-PLLA and PDLA-PEG-PDLA is 1:1, and the amount of PEG300k is 40wt%, based on the total mass of PLLA-PEG-PLLA, PDLA-PEG-PDLA and PEG300k.

[0128] The pore size of the pore structure between the fiber membranes is 5.2 micrometers, and the pore size of the pore structure on the surface of the fiber membrane is 138 nanometers.

[0129] Example 7

[0130] The method was carried out according to Example 1, except that in step S1, 1.03g of PLLA-PEG-PLLA, 0.05g of PDLA-PEG-PDLA and 0.72g of PEG300k were dissolved in 28.2g of chloroform to obtain a mixed solution (concentration of 6wt%), and a three-dimensional fiber membrane A7 was prepared.

[0131] The molar ratio of PLLA-PEG-PLLA and PDLA-PEG-PDLA is 1:0.05. Based on the total mass of PLLA-PEG-PLLA, PDLA-PEG-PDLA, and PEG300k, the amount of PEG300k is 40 wt%.

[0132] The pore size of the pore structure between the fiber membranes is 4.6 micrometers, and the pore size of the pore structure on the surface of the fiber membrane is 129 nanometers.

[0133] Example 8

[0134] Following the method of Example 1, 0.63 g of PLLA-PEG-PLLA, 0.63 g of PDLA-PEG-PDLA, and 0.54 g of PEG300k were dissolved in 28.2 g of chloroform, such that the amount of PEG300k was 30 wt%, based on the total mass of PLLA-PEG-PLLA, PDLA-PEG-PDLA, and PEG300k. The molar ratio of PLLA-PEG-PLLA to PDLA-PEG-PDLA was 1:1. A three-dimensional fiber membrane A8 was thus prepared.

[0135] The pore size of the pore structure between the fiber membranes is 4.5 micrometers, and the pore size of the pore structure on the surface of the fiber membrane is 109 nanometers.

[0136] Example 9

[0137] Following the method of Example 1, the electrospun membrane was post-treated by shaking it in deionized water at 75°C for 12 hours. A three-dimensional fiber membrane A9 was then obtained.

[0138] The pore size of the pore structure between the fiber membranes is 4.4 micrometers, and the pore size of the pore structure on the surface of the fiber membrane is 120 nanometers.

[0139] Comparative Example 1

[0140] The procedure was carried out according to Example 1, except that in step (1), 1.08 g of PLLA-PEG-PLLA and 0.72 g of PEG300k were dissolved in 28.2 g of chloroform to obtain a mixed solution (concentration of 6 wt%). Based on the total mass of PLLA-PEG-PLLA, PDLA-PEG-PDLA and PEG300k, the amount of PEG300k was 40 wt%. A three-dimensional fiber membrane D1 was obtained.

[0141] Comparative Example 2

[0142] The procedure was carried out according to Example 5, except that in step (1), 0.9 g of PLLA-PVA-PLLA and 0.9 g of PDLA-PVA-PDLA were dissolved in 28.2 g of chloroform to obtain a mixed solution. A three-dimensional fiber membrane D2 was then prepared.

[0143] Test case

[0144] The fiber diameter, open-circuit voltage, elastic modulus, and degradation time of the fiber membranes prepared in the examples and comparative examples were tested, and the results are shown in Table 1.

[0145] Table 1

[0146] Fiber diameter (nm) Open circuit voltage (V) Elastic modulus (kPa) Degradation time (weeks) A1 380 25 580 12 A2 762 14 645 15 A3 354 12 452 10 A4 276 9 514 10 A5 401 23 570 12 A6 427 18 596 13 A7 362 6 417 7 A8 343 20 561 12 A9 369 23 571 12 D1 383 3 400 6 D2 110 5 493 10

[0147] As can be seen from the results in Table 1, the lactic acid copolymer stereocomposite fiber membranes provided in Examples 1-9 of the present invention have high open-circuit voltage and suitable degradation rate under the premise of high mechanical strength.

[0148] Examples 1, 5, 8-9, which further satisfy the preferred scope of the present invention, achieve significantly better technical effects. The resulting stereocomposite fiber membrane has a suitable fiber diameter, a higher open-circuit voltage (not less than 20V), higher mechanical strength (not less than 560kPa), and a suitable degradation rate with a degradation time of no more than 12 weeks.

[0149] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A lactic acid copolymer stereopolymer fiber membrane, characterized in that, The fiber membrane was found to have diffraction peaks at 2θ = 11-13° by XRD, with a full width at half maximum (FWHM) of 0.5-1.5°. These diffraction peaks were attributed to stereocomposite crystals (110). SC .

2. The fiber membrane according to claim 1 or 2, wherein, In the fiber membrane, the fibers forming the fiber membrane have a micron-scale pore structure between them, and the surface of the fibers forming the fiber membrane has a nano-scale pore structure. Preferably, the pore size of the pore structure between the fibers is 1-30 micrometers, more preferably 2-10 micrometers; Preferably, the pore size of the pore structure on the fiber surface is 10-400 nanometers, and more preferably 50-200 nanometers.

3. The fiber membrane according to claim 1 or 2, wherein, The polymers forming the fiber membrane include L-lactic acid copolymers and D-lactic acid copolymers; Preferably, the L-lactic acid copolymer has an ABA structure, wherein segment A is a L-polylactic acid segment, and segment B is selected from at least one of polypolyol segments, polyester segments, polyvinyl alcohol segments, and polyhydroxyacetic acid; Preferably, the dextrorotatory lactic acid copolymer has a CDC structure, wherein segment C is a dextrorotatory polylactic acid segment, and segment D is selected from at least one of polypolyol segments, polyester segments, polyvinyl alcohol segments, and polyglycolic acid; Preferably, the polypolyol in the polypolyol segment is selected from at least one of polyethylene glycol, polypropylene glycol, and polybutanediol; Preferably, the polyester in the polyester segment is selected from at least one of polycaprolactone, polybutylene succinate, and polyhydroxyalkanoates.

4. The fiber membrane according to claim 3, wherein, The molar ratio of the L-lactic acid copolymer to the D-lactic acid copolymer is 1:0.1-10, preferably 1:0.5-2; Preferably, the number-average molecular weight of the polymer forming the fiber membrane is ≥20,000 g / mol, and more preferably ≥50,000 g / mol.

5. A method for preparing a lactic acid copolymer stereocomposite fiber membrane, characterized in that, The method includes: S1. In the presence of water-soluble polymer materials and solvents, L-lactic acid copolymer and D-lactic acid copolymer are mixed evenly to obtain a mixed solution; S2. Electrospin the mixed solution to obtain an electrospun membrane; S3. The electrospun membrane is post-treated, dried and cooled to obtain a three-dimensional composite fiber membrane.

6. The method according to claim 5, wherein, The L-lactic acid copolymer has an ABA structure, wherein segment A is a L-polylactic acid segment, and segment B is selected from at least one of polypolyol segments, polyester segments, polyvinyl alcohol segments, and polyglycolic acid. Preferably, the dextrorotatory lactic acid copolymer has a CDC structure, wherein segment C is a dextrorotatory polylactic acid segment, and segment D is selected from at least one of polypolyol segments, polyester segments, polyvinyl alcohol segments, and polyglycolic acid; Preferably, the polypolyol in the polypolyol segment is selected from at least one of polyethylene glycol, polypropylene glycol, and polybutanediol; Preferably, the polyester in the polyester segment is selected from at least one of polycaprolactone, polybutylene succinate, and polyhydroxyalkanoates; Preferably, the number-average molecular weight of the L-lactic acid copolymer is ≥20,000 g / mol, and more preferably ≥50,000 g / mol; Preferably, the number-average molecular weight of the dextrorotatory lactic acid copolymer is ≥20,000 g / mol, and more preferably ≥50,000 g / mol; And / or, the molar ratio of the L-lactic acid copolymer to the D-lactic acid copolymer is 1:0.1-10, preferably 1:0.5-2.

7. The method according to claim 5 or 6, wherein, The water-soluble polymer material is a natural water-soluble polymer material and / or a synthetic water-soluble polymer material; Preferably, the water-soluble polymer material is selected from at least one of polyethylene glycol, polyvinylpyrrolidone, and carboxymethyl cellulose; Preferably, based on the total mass of the L-lactic acid copolymer, the D-lactic acid copolymer, and the water-soluble polymer material, the amount of the water-soluble polymer material is 5-60 wt%. Preferably, the solvent is selected from at least one of chloroform, dichloromethane, and N,N-dimethylformamide; Preferably, the concentration of the mixed solution is 3-20 wt%.

8. The method according to any one of claims 5-7, wherein, The conditions for electrospinning include: needle diameter of 18-26G, voltage of 10-25kV, distance from needle tip to substrate of 5-20cm, and liquid dispensing speed of 1-5mL / h. And / or, the post-processing conditions include: immersing the electrospun membrane in deionized water; Preferably, the soaking time is 6-24 hours, and the soaking temperature is 25-75°C; And / or, the drying conditions include: a temperature of 80-160°C and a drying time of 0.5-6 hours.

9. A lactic acid copolymer stereocomposite fiber membrane prepared by the method according to any one of claims 5-8.

10. The use of the lactic acid copolymer stereocomposite fiber membrane according to any one of claims 1-4 or 9 in at least one of the fields of biosensing, tissue engineering and drug delivery.

Images