Nanofiber sheet for soft tissue regeneration and strengthening and method for manufacturing same

Abstract

To provide a nanofiber sheet for soft tissue regeneration and reinforcement and a method for producing the same. [Solution] The nanofiber sheet for soft tissue regeneration and reinforcement contains biodegradable polymers including poly(glycolic-co-lactic acid) (PGLA) and polyvinylpyrrolidone (PVP), and the molar ratio of glycolic acid block:lactic acid block of the poly(glycolic-co-lactic acid) (PGLA) is 30:70 to 40:60.

Description

[Technical Field]

[0001] The present invention relates to a nanofiber sheet for regenerating and reinforcing soft tissue and a method for manufacturing the same. More specifically, the nanofiber sheet for regenerating and reinforcing soft tissue comprises a biodegradable polymer including poly(glycolic-co-lactic acid) (PGLA) and polyvinylpyrrolidone (PVP), and is characterized in that the molar ratio of glycolic acid block to lactic acid block of the poly(glycolic-co-lactic acid) (PGLA) is 30:70 to 40:60. [Background technology]

[0002] Tissue engineering is a field of regenerative medicine ranging from cells to artificial organs. It is based on the study of biological and engineering techniques, from biological substances to materials, that can help restore tissues and organs, and is recognized as one of the key technologies in the future of life science and medicine. Various methods are being researched to achieve the goal of restoring, maintaining, and improving bodily functions by understanding the correlation between the structure and function of biological tissues and creating and transplanting biosubstitutes.

[0003] One of the main techniques in tissue engineering is to create a support or scaffold that acts as a base for cells to attach and grow. Unlike two-dimensional membranes or capsules, a scaffold is a three-dimensional structure that refers to a space where all cells in the body can attach, differentiate, and proliferate.

[0004] Scaffolds play a very important role in tissue engineering, as they play a vital role in the growth of cells seeded within their porous structure and cells migrating from the surrounding tissue.

[0005] The vast majority of cells in the human body are adherent cells that grow by adhering to one another, and if there is no place for them to attach, they will not grow and will die. Therefore, the scaffold must provide an appropriate environment for cell adhesion, differentiation, growth, and migration.

[0006] Furthermore, these scaffolds must function as a base to allow cells to adhere and form tissues with sufficient three-dimensional structure, and because they are the most fundamental element in creating artificial biological tissues, biocompatibility, biodegradability, toxicity, mechanical, and structural properties must all be considered.In recent years, there has been active research into the development of scaffolds for tissue regeneration using natural materials, synthetic polymers, bioceramics, and polymer-ceramic composites as porous tissue engineering scaffolds.

[0007] In addition, nanostructures such as nanofibers and nanoparticles are one of the effective structures for supporting cells in soft tissues, and there have been many reports that their structural advantages have a positive effect on cell proliferation, generation, and differentiation.

[0008] Therefore, the present inventors focused on the above-mentioned technology and produced a nanofiber sheet for regenerating and reinforcing soft tissue as a scaffold for tissue regeneration, thereby completing the present invention.

[0009] Generally, an electrospinning system can be broadly divided into a fiber raw material solution supply unit, a high-voltage supply unit, and a collector unit where nanofibers are formed. Other spinning environment factors (humidity and temperature) must be maintained at optimally consistent conditions. The solution supply unit consists of a syringe pump and syringe (or nozzle) that precisely dispenses the solution at a constant rate. Fiber properties can be controlled by designing the syringe needle's shape, diameter, and material. The high-voltage supply unit controls voltage and current using an insulated cable consisting of a (+) pole that charges the high-dielectric-constant polymer solution and a (-) pole where the charged solution is collected in the form of nanofiber filaments. The collector unit, where nanofibers are collected, allows for the alignment of nanofiber strands to be controlled by designing its shape, movement, and speed, enabling the production of materials with various shapes tailored to specific purposes. Materials used in electrospinning are generally in the form of a well-dissolved solution. The solution properties of the polymer used during electrospinning have a significant impact on fiber formation. These solution properties include the concentration, viscosity, surface tension, conductivity, dielectric properties, and volatility of the polymer solution. The concentration of a polymer solution is closely related to its viscosity. Viscosity, which indicates the entanglement and fluidity of polymer chains, is known to be an important factor affecting the morphology, diameter, and ejection speed of fibers produced during electrospinning. While this varies depending on the polymer's properties, it has been reported that a viscosity of approximately 0.5 to 50 poise is sufficient for fiber formation; too high or too low a viscosity prevents fiber formation. Electrospinning is a technique for producing fibers with a size of several nanometers to several micrometers by applying electrostatic force to a polymer solution or melt, resulting in a large potential difference between the charged polymer and a grounded current collector. This spinning technique requires inexpensive and simple equipment and allows for fast spinning speeds and small amounts of spinning. It can also produce sheet-like fibers and facilitates the addition of additives. A technology has been proposed for using nanofibers, particularly those obtained by electrospinning polymer solutions, as a physical barrier to prevent tissue adhesions.

[0010] Professor Benjamin Chu of the United States has attempted to fabricate biodegradable nanofibers containing antibiotics using PLGA, a commonly used tissue engineering material, as a base material for use as a tissue adhesion prevention membrane. However, this technology has the drawback that PLGA, the main material, is a hydrophobic polymer, and when fabricated into nanofiber sheets, they experience severe shrinkage in aqueous solutions (Non-Patent Document 1: Hongliang Jiang, Benjamin Chu, "Preparation and characterization of ibuprofen-loaded poly(lactide-co-glycolide) / poly(ethylene glycol)-g-chitosan electrospun membranes," J. Biomater. Sci. Polymer Edn, Vol. 15, No. 3, 279-296, 2004).

[0011] Another representative soft tissue strengthening and repair sheet currently on the market is NEOVEIL from GUNZE. NEOVEIL is a fiber woven nonwoven sheet made using micro-unit thermocompression bonding, rather than a nanofiber product. NEOVEIL biodegrades rapidly in vivo after three weeks, and there is a problem that the desired effect on regenerating and strengthening biological soft tissue cannot be achieved if the soft tissue regeneration and strengthening takes more than three weeks.

[0012] Therefore, the present inventors have conducted research to solve the above problems and have developed a nanofiber sheet for soft tissue regeneration and reinforcement, which comprises a biodegradable polymer including poly(glycolic-co-lactic acid) (PGLA) and polyvinylpyrrolidone (PVP), and in which the molar ratio of glycolic acid block to lactic acid block of the poly(glycolic-co-lactic acid) (PGLA) is 30:70 to 40:60. They have found that the nanofiber sheet for soft tissue regeneration and reinforcement maintains its physical properties in vivo for more than 3 weeks and is absorbed by the body within 15 weeks, leading to the completion of the present invention. [Prior art documents] [Non-patent literature]

[0013] [Non-Patent Document 1] Hongliang Jiang, Benjamin Chu, “Preparation and characterization of ibuprofen-loaded poly(lactide-co-glycolide) / poly(ethylene glycol)-g-chitosan electrospun membranes”, J. Biomater. Sci. Polymer Edn, Vol. 15. No. 3, 279-296 2004 Summary of the Invention [Problem to be solved by the invention]

[0014] The present invention has been devised to solve the above-mentioned problems of the prior art, and has an object to provide a nanofiber sheet for regenerating and strengthening soft tissue.

[0015] Another object of the present invention is to provide a method for producing the nanofiber sheet for regenerating and strengthening soft tissue. [Means for solving the problem]

[0016] As a technical means for achieving the above technical objectives, one aspect of the present invention provides a nanofiber sheet for soft tissue regeneration and reinforcement, which comprises a biodegradable polymer including poly(glycolic-co-lactic acid) (PGLA) and polyvinylpyrrolidone (PVP), wherein the molar ratio of glycolic acid block to lactic acid block of the poly(glycolic-co-lactic acid) (PGLA) is 30:70 to 40:60.

[0017] The composition may contain 60 to 90 parts by weight of the poly(glycolic-co-lactic acid) (PGLA) and 10 to 40 parts by weight of the polyvinylpyrrolidone (PVP).

[0018] The average diameter of the fiber cross section may be 500 to 990 nm.

[0019] Furthermore, another aspect of the present invention provides a method for producing a nanofiber sheet for soft tissue regeneration and reinforcement, the method comprising: a polymer solution obtaining step of dissolving a biodegradable polymer including poly(glycolic-co-lactic acid) (PGLA) and polyvinylpyrrolidone (PVP) in a solvent including dichloromethane (DCM) and dimethylformamide (DMF) to obtain a polymer solution; a nanofiber obtaining step of electrospinning the polymer solution to obtain nanofibers; and a heat treatment step of heat-treating the nanofibers.

[0020] The molar ratio of glycolic acid block to lactic acid block of the poly(glycolic-co-lactic acid) (PGLA) may be 30:70 to 40:60.

[0021] The composition may contain 60 to 90 parts by weight of the poly(glycolic-co-lactic acid) (PGLA) and 10 to 40 parts by weight of the polyvinylpyrrolidone (PVP).

[0022] The solvent may contain 50 to 70 parts by weight of dichloromethane (DCM) and 30 to 50 parts by weight of the dimethylformamide (DMF).

[0023] The polymer solution may contain 90 parts by weight of the solvent and 8 to 15 parts by weight of the biodegradable polymer.

[0024] The electrospinning conditions for the nanofiber obtaining step can be a voltage of 15 to 30 kV, a spinning distance of 10 to 20 cm, and a discharge rate of 0.5 to 2 ml / h.

[0025] The heat treatment step may be performed at 50 to 100° C. for 10 to 35 minutes.

[0026] The nanofibers may have an average cross-sectional diameter of 500 to 990 nm. [Effects of the Invention]

[0027] The nanofiber sheet for regenerating and strengthening soft tissue according to the present invention can maintain its physical properties in vivo for more than three weeks and can regenerate and strengthen soft tissue, and can be absorbed by the body within 15 weeks and is harmless to the human body.

[0028] Furthermore, the nanofiber sheet for regenerating and strengthening soft tissue may have reduced shrinkage in an aqueous solution. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a nanofiber sheet for regenerating and strengthening soft tissues prepared according to Example (1) of the present invention, and an SEM photograph thereof magnified 1000 times. [Figure 2] 1 is a SEM photograph showing a nanofiber sheet for regenerating and strengthening soft tissues manufactured according to Example (1) of the present invention at 5000 times magnification. [Figure 3] 1 is a SEM photograph showing a nanofiber sheet for regenerating and strengthening soft tissues manufactured according to Comparative Example (1) of the present invention at 5000 times magnification. [Figure 4] 1 is a graph showing the change in tensile strength of the nanofiber sheet for soft tissue regeneration and reinforcement manufactured according to Example (1) of the present invention. [Figure 5] 1 is a graph showing the tensile strength change of NEOVEIL brand sheets. [Figure 6] 1 is a SEM photograph at 5000 times magnification of a nanofiber sheet for regenerating and reinforcing soft tissue prepared according to Comparative Example (4) of the present invention after three days of cell proliferation. [Figure 7] 1 is a SEM photograph at 5000 times magnification of the nanofiber sheet for regenerating and reinforcing soft tissue prepared according to Example (2) of the present invention after 3 days of cell proliferation. [Figure 8] 1 is a SEM photograph at 5000 times magnification of the nanofiber sheet for regenerating and reinforcing soft tissue prepared according to Example (3) of the present invention after 3 days of cell proliferation. [Figure 9] 1 is a SEM photograph showing a 5000x magnification of a nanofiber sheet for regenerating and reinforcing soft tissue prepared according to Example (1) of the present invention after three days of cell proliferation. [Figure 10] 1 is a SEM photograph at 5000 times magnification of the nanofiber sheet for regenerating and reinforcing soft tissue prepared according to Example (4) of the present invention after 3 days of cell proliferation. [Figure 11]1 is a SEM photograph showing a nanofiber sheet for regenerating and reinforcing soft tissues manufactured according to Comparative Example (5) of the present invention at 2500 times magnification. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention may, however, be embodied in various different forms and should not be construed as limited to the embodiments set forth herein, but rather as defined by the claims set forth below.

[0031] In addition, the terms used in the present invention are merely used to describe specific embodiments and are not intended to limit the present invention. A singular expression includes a plural expression unless the context clearly indicates otherwise. Throughout the specification of the present invention, when a part "comprises" a certain element, it means that it can further include other elements, not excluding other elements, unless otherwise specified to the contrary.

[0032] A first aspect of the present invention provides a nanofiber sheet for soft tissue regeneration and reinforcement, which comprises a biodegradable polymer including poly(glycolic-co-lactic acid) (PGLA) and polyvinylpyrrolidone (PVP), and the molar ratio of glycolic acid block to lactic acid block of the poly(glycolic-co-lactic acid) (PGLA) is 30:70 to 40:60.

[0033] The nanofiber sheet for regenerating and strengthening soft tissue according to the first aspect of the present invention will be described in detail below.

[0034] In one embodiment of the present invention, the nanofiber sheet for soft tissue regeneration and strengthening contains a biodegradable polymer including poly(glycolic-co-lactic acid) (PGLA) and polyvinylpyrrolidone (PVP), which reduces shrinkage in aqueous solution compared to when poly(glycolic-co-lactic acid) (PGLA) alone is used as the biodegradable polymer, and can maintain its physical properties in vivo for more than three weeks to regenerate and strengthen soft tissue. It can also be absorbed by the body within 15 weeks and is harmless to the body.

[0035] Furthermore, by using poly(glycolic-co-lactic acid) (PGLA) in which the molar ratio of glycolic acid block to lactic acid block is 30:70 to 40:60, the average diameter of the nanofiber cross section can be set to 500 to 990 nm.

[0036] When the molar ratio of the glycolic acid block to the lactic acid block of the poly(glycolic-co-lactic acid) (PGLA) is less than 30 and more than 70, the biodegradable polymer is not partially dissolved in the solvent, making it difficult to apply the electrospinning method of the present invention. Alternatively, even if nanofibers are formed, they may not be completely fiberized, resulting in irregular nanofiber thicknesses and the formation of portions with large thickness variations.

[0037] When the molar ratio of the glycolic acid block to the lactic acid block of the poly(glycolic-co-lactic acid) (PGLA) is greater than 40 and less than 60, the polymer is more likely to dissolve in a solvent, but the fiber diameter may become thinner. Therefore, the polymer may be biodegraded more quickly in vivo after electrospinning.

[0038] In one embodiment of the present invention, the average cross-sectional diameter of the fiber may be 500 to 990 nm, preferably 550 to 850 nm, and more preferably 550 to 800 nm. If the average cross-sectional diameter of the nanofiber is less than 500 nm, the nanofiber may have a large surface area, but it may be difficult to form a support layer necessary for cell growth. If the average cross-sectional diameter of the nanofiber is more than 990 nm, the interfiber space may become large, which may inhibit cell growth.

[0039] A second aspect of the present invention provides a method for producing a nanofiber sheet for soft tissue regeneration and reinforcement, the method comprising: a polymer solution obtaining step of dissolving a biodegradable polymer including poly(glycolic-co-lactic acid) (PGLA) and polyvinylpyrrolidone (PVP) in a solvent including dichloromethane (DCM) and dimethylformamide (DMF) to obtain a polymer solution; a nanofiber obtaining step of electrospinning the polymer solution to obtain nanofibers; and a heat treatment step of heat treating the nanofibers.

[0040] Detailed descriptions of parts that overlap with the first aspect of the present invention have been omitted, but the contents described for the first aspect of the present invention may be similarly applied even if the description is omitted for the second aspect.

[0041] Hereinafter, the method for producing a nanofiber sheet for regenerating and strengthening soft tissue according to the second aspect of the present invention will be described in detail step by step.

[0042] First, in one embodiment of the present invention, a polymer solution obtaining step may be included in which a biodegradable polymer including poly(glycolic-co-lactic acid) (PGLA) and polyvinylpyrrolidone (PVP) is dissolved in a solvent including dichloromethane (DCM) and dimethylformamide (DMF) to obtain a polymer solution.

[0043] In one embodiment of the present invention, the molar ratio of glycolic acid block to lactic acid block of the poly(glycolic-co-lactic acid) (PGLA) may be 30:70 to 40:60.

[0044] In one embodiment of the present invention, the nanofiber sheet may contain 60 to 90 parts by weight of poly(glycolic-co-lactic acid) (PGLA) and 10 to 40 parts by weight of polyvinylpyrrolidone (PVP). If the amount of polyvinylpyrrolidone (PVP) is less than 10 parts by weight, a secondary fixation step using sutures or tissue adhesive may be necessary when the nanofiber sheet is applied to soft tissue. Therefore, if the amount of PVP is less than 10 parts by weight, the sheet may detach from the soft tissue unless a fixation step is performed. If the amount of polyvinylpyrrolidone (PVP) is more than 40 parts by weight, soft tissue regeneration may not occur.

[0045] In one embodiment of the present invention, the solvent may contain 50 to 70 parts by weight of dichloromethane (DCM) and 30 to 50 parts by weight of dimethylformamide (DMF). If the amount of dimethylformamide (DMF) is less than 30 parts by weight, the biodegradable polymer may not be dissolved to an extent that allows electrospinning. If the amount of dimethylformamide (DMF) is more than 50 parts by weight, the biodegradable polymer may not be significantly dissolved.

[0046] In one embodiment of the present invention, the polymer solution may contain 8 to 15 parts by weight of the biodegradable polymer relative to 90 parts by weight of the solvent. If the amount of the biodegradable polymer is less than 8 parts by weight, the cross-sectional diameter of the nanofiber may be less than 500 nm, and the nanofiber sheet may be damaged even by a small impact. If the amount of the biodegradable polymer is more than 15 parts by weight, the cross-sectional diameter of the nanofiber may be less than 990 nm, and when the nanofiber sheet is applied to soft tissue, soft tissue regeneration may not be effective.

[0047] Meanwhile, in one embodiment of the present invention, the electrospinning conditions for the nanofiber obtaining step may be a voltage of 15-30 kV, a spinning distance of 10-20 cm, and a discharge rate of 0.5-2 ml / h. If the voltage, spinning distance, and discharge rate are outside the above ranges, the average cross-sectional diameter of the nanofibers may be smaller than 500 nm or larger than 990 nm.

[0048] Meanwhile, in one embodiment of the present invention, the heat treatment step may be performed at 50-100°C for 10-35 minutes. The reason for performing the heat treatment is to shrink the nanofiber sheet in vivo, so that the nanofiber sheet can survive in vivo for 3 to 15 weeks. If the temperature and time of the heat treatment step are outside the range, the strength of the nanofibers may decrease, and the nanofiber sheet may not survive in vivo for 3 to 15 weeks.

[0049] On the other hand, the average diameter of the cross section of the nanofibers may be 500 to 990 nm.

[0050] Although the present invention may be embodied in many different forms, it is not intended to be limited to the embodiments set forth herein, and the present invention is not limited to the embodiments set forth herein.

[0051] Material preparation

[0052] Three types of poly(glycolic-co-lactic acid) (PGLA) were used. PGLA with a 9:1 molar ratio (G:L) of glycolic acid block (G):lactic acid block (L) was purchased from Meta Biomed and labeled Glacomer 91. PGLA with a G:L ratio of 5:5 was purchased from Joinsmed. Its molecular weight ranged from 54,000 to 69,000. PGLA with a G:L ratio of 35:65 was purchased from CUREBIOTECH and labeled Curesorb-PGLA3565. Polyvinylpyrrolidone (PVP) was purchased from Sigma-Aldrich and had a maximum molecular weight of 1,300,000.

[0053] 1. Example (1)

[0054] 1. Polymer solution preparation step

[0055] (1) A biodegradable polymer was prepared by mixing PGLA (G:L=35:65) and PVP (70:30) in a weight ratio.

[0056] (2) A solvent was prepared by mixing dichloromethane (hereinafter referred to as DCM) and dimethylformamide (hereinafter referred to as DMF) in a weight ratio of 60:40.

[0057] (3) 11 parts by weight of the biodegradable polymer was dissolved in 89 parts by weight of the solvent to obtain a polymer solution.

[0058] 2. Nanofiber Acquisition Steps

[0059] The polymer solution was electrospun at a voltage of 20 kV, a spinning distance of 15 cm, and a discharge rate of 1 ml / h to produce nanofibers.

[0060] 3. Heat treatment step

[0061] The nanofibers were subjected to heat treatment using an oven at a heat treatment temperature of 75 to 85°C for a heat treatment time of 30 minutes.

[0062] 1 and 2, it can be seen that the average diameter of the nanofiber cross section of the nanofiber sheet of the present invention is 500 to 990 nm.

[0063] 2. Comparative Example (2)

[0064] This example was the same as Example (1) except that PVP was replaced with poly(ethylene oxide) (hereinafter referred to as PEO) and the electrospinning voltage was changed to 18 kV.

[0065] [Table 1]

[0066] Referring to FIG. 3, it can be seen that when the composition of the biodegradable polymer is changed to PGLA and PEO, the diameter of the nanofibers becomes larger than 990 nm.

[0067] 3. Comparative Example (2)

[0068] This is the same as Example (1) above, except that PGLA with G:L=5:5 was used.

[0069] 4. Comparative Example (3)

[0070] This is the same as Example (1) above, except that PGLA with G:L=9:1 was used.

[0071] 5. Comparative Example (4)

[0072] This was the same as Example (1) above, except that the polymer solution was obtained by changing the amounts of PGLA to 100 parts by weight and PVP to 0 parts by weight.

[0073] 6. Example (2)

[0074] This was the same as Example (1) above, except that the polymer solution was obtained by changing the amounts of PGLA to 90 parts by weight and PVP to 10 parts by weight.

[0075] 7. Example (3)

[0076] This was the same as Example (1) above, except that the polymer solution was obtained by changing the amounts of PGLA and PVP to 80 parts by weight and 20 parts by weight, respectively.

[0077] 8. Example (4)

[0078] This was the same as Example (1) above, except that the polymer solution was obtained by changing the amounts of PGLA and PVP to 60 parts by weight and 40 parts by weight, respectively.

[0079] 9. Comparative Example (5)

[0080] The procedure was the same as in Example (1) above, except that the weight mixture ratio of the solvents dichloromethane (hereinafter referred to as DCM) and dimethylformamide (hereinafter referred to as DMF) was changed from 60:40 to 20:10, using dimethylacetamide and acetone.

[0081] Table 2 below shows the molar ratios of G and L, the weight contents of PGLA and PVP, and whether electrospinning is possible for the remaining Examples (1) to (4) and Comparative Examples (2) to (4), excluding the above Comparative Examples (1) and (5).

[0082] [Table 2]

[0083] Referring to Table 2, it can be seen that electrospinning is not possible when G:L=5:5 or 9:1.

[0084] Experimental Example 1. Biodegradation test of Example (1)

[0085] To observe the biodegradability of the sheets, biodegradation test samples were prepared for the nanofiber sheet prepared according to Example (1) of the present invention and the sheet manufactured under the NEOVEIL brand of Gunze. After weighing out 0.3 g of each sample, the samples to be tested after 7, 14, 21, and 28 days were labeled as Day 7, 14, 21, and 28. A total of 12 samples were prepared, three for each level.

[0086] The sheets were then immersed in PBS at 36.5°C in a water bath and left to stand. After that, they were removed and dried every 7, 14, 21, or 28 days depending on the leveling number, and then placed in a vacuum oven for a specified period of time. The weight of the sheets was then measured to determine how much they had lost weight compared to the initial weight.

[0087] The test results of Experimental Example 1 are shown in Table 3 below.

[0088] [Table 3]

[0089] Referring to Table 3 above, it was confirmed that the NEOVEIL brand sheet rapidly decomposed after 3 weeks, and after 4 weeks it was decomposed by 52.89%, which was about 10 times more decomposed than the nanofiber sheet prepared according to Example (1) of the present invention.

[0090] Experimental Example 2. Tensile strength test of Example (1)

[0091] Test specimens of the nanofiber sheet prepared according to Example (1) of the present invention and the NEOVEIL brand sheet from GUNZE were prepared, measuring 0.5 cm x 10 cm. The test specimens to be tested after 7, 14, 21, and 28 days were labeled Day 7, 14, 21, and 28. A total of 25 specimens were prepared, five for each level. The sheets were then immersed in PBS at 36.5°C in a water bath. They were then removed and dried every 7, 14, 21, and 28 days, depending on the number of levels. The tensile strength of the sheets was then measured using a UTM with a load cell of 100 N and an extension speed of 5 mm / min.

[0092] The test results of Experimental Example 2 are shown in Table 4 below.

[0093] [Table 4]

[0094] Referring to Table 4 above, it can be seen that the NEOVEIL brand sheet has lower tensile strength from the beginning of the test than the nanofiber sheet prepared according to Example (1) of the present invention. Also, referring to Figures 4 and 5, it can be seen that the tensile strength of the NEOVEIL brand sheet decreases more quickly than the tensile strength of the nanofiber sheet prepared according to Example (1) of the present invention.

[0095] Experimental Example 3: Cell culture test of Example (1)

[0096] A total of five samples containing PLGA (65:35) and PVP (0%, 10%, 20%, 30%, and 40%) were subjected to cell culture. First, sheets were punched out to the size of 12-well plates, and both sides of the sheets were UV-sterilized for 30 minutes. Then, the sheets were placed in the 12-well plates and PBS was added to wet the sheets. After immediate suction of the PBS, a glass ring was inserted, and cells and medium were seeded at a ratio of 50,000 cells per 2 mL. After 1, 3, 5, and 7 days, cells were fixed at room temperature for 30 minutes in PBS containing 2.5% glutaraldehyde. To remove glutaraldehyde, the cells were washed three times with PBS and then three times with sterile water. Dehydration was performed using 2 mL each of 50, 70, and 90% EtOH at room temperature. The cells were then dried in a clean bench for 24 hours.

[0097] Referring to Figures 6 to 10, it can be seen that when the nanofiber sheet contains 0 to 30 parts by weight of PVP, cell proliferation is smooth, but when the content is 40 parts by weight, cell proliferation is insufficient.

[0098] Experimental Example 4. Annealing shrinkage test of Example (1)

[0099] For the shrinkage experiment, the sheet was cut into 2x2cm pieces, annealed at temperatures ranging from 70°C to 120°C for 30, 60, and 90 minutes, and then immersed in PBS at 37°C for 7 days. The shrinkage rate of the sheet was then calculated.

[0100] The test results of Experimental Example 4 are shown in Table 5 below.

[0101] [Table 5]

[0102] Referring to Table 5 above, it can be seen that when the heat treatment is carried out at 80°C or higher, the shrinkage rate is stable.

[0103] 11, when the solvent composition of the present invention was changed to a 20:10 weight ratio of dimethylacetamide and acetone, the nanofiber cross-sectional diameter became irregular and varied significantly. Also, melting of the nanofibers was observed when heat-treated at 120°C or higher.

[0104] Although the present invention has been described in detail above with reference to the drawings and preferred embodiments, the scope of the technical idea of ​​the present invention is not limited to these drawings and embodiments. Therefore, various modifications or equivalent embodiments may exist within the scope of the technical idea of ​​the present invention. Therefore, the scope of the technical idea of ​​the present invention is interpreted by the claims, and technical ideas equivalent to or within the scope of the claims belong to the scope of the present invention. [Industrial Applicability]

[0105] The nanofiber sheet for regenerating and strengthening soft tissue according to the present invention can maintain its physical properties in vivo for more than three weeks and regenerate and strengthen soft tissue, and can be absorbed by the body within 15 weeks and is harmless to the human body.

[0106] Furthermore, the nanofiber sheet for regenerating and strengthening soft tissue may have reduced shrinkage in an aqueous solution.

Claims

1. a polymer solution obtaining step of dissolving a biodegradable polymer including poly(glycolic-co-lactic acid) (PGLA) and polyvinylpyrrolidone (PVP) in a solvent including dichloromethane (DCM) and dimethylformamide (DMF) to obtain a polymer solution; a nanofiber obtaining step of electrospinning the polymer solution to obtain nanofibers; and a heat treatment step of heat treating the nanofibers. A method for producing a nanofiber sheet for soft tissue regeneration and reinforcement, characterized by:

2. The molar ratio of glycolic acid block to lactic acid block of the poly(glycolic-co-lactic acid) (PGLA) is 30:70 to 40:

60. A method for producing the nanofiber sheet for soft tissue regeneration and reinforcement according to claim 1.

3. The poly(glycolic-co-lactic acid) (PGLA) is contained in an amount of 60 to 90 parts by weight, and the polyvinylpyrrolidone (PVP) is contained in an amount of 10 to 40 parts by weight. A method for producing the nanofiber sheet for soft tissue regeneration and reinforcement according to claim 1.

4. The solvent contains 50 to 70 parts by weight of dichloromethane (DCM) and 30 to 50 parts by weight of dimethylformamide (DMF). A method for producing the nanofiber sheet for soft tissue regeneration and reinforcement according to claim 1.

5. The polymer solution contains 8 to 15 parts by weight of the biodegradable polymer relative to 90 parts by weight of the solvent. A method for producing the nanofiber sheet for soft tissue regeneration and reinforcement according to claim 1.

6. The electrospinning conditions for the nanofiber obtaining step are a voltage of 15 to 30 kV, a spinning distance of 10 to 20 cm, and a discharge rate of 0.5 to 2 ml / h. A method for producing the nanofiber sheet for soft tissue regeneration and reinforcement according to claim 1.

7. The heat treatment step is performed at 50 to 100° C. for 10 to 35 minutes. A method for producing the nanofiber sheet for soft tissue regeneration and reinforcement according to claim 1.

8. The average cross-sectional diameter of the nanofibers is 500 to 990 nm. A method for producing the nanofiber sheet for soft tissue regeneration and reinforcement according to any one of claims 1 to 7.

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