Preparation device of high-orientation-degree electrostatic spinning nanofiber absorbable surgical suture

Abstract

The utility model discloses a preparation device of a high-orientation-degree electrostatic spinning nanofiber absorbable surgical suture, which comprises a spinning device provided with a liquid supply box, a high-voltage power supply and an electrostatic spinning nozzle. The electrostatic spinning device is characterized in that two conductive conveying belts which move oppositely and are used for adhering and fixing nanofibers formed by spraying trickles and driving the nanofibers to move downwards are vertically arranged below the electrostatic spinning nozzle in parallel, and a receiving area used for adhering the nanofibers which are consistent or similar in arrangement direction is formed between the two conductive conveying belts; a whipping area is formed between the electrostatic spinning nozzle and the tops of the conductive conveying belts, and a collecting plate used for intercepting nanofibers adhered and fixed between the two conductive conveying belts and flatly laying, accumulating and stacking the nanofibers to form oriented nanofiber bundles is arranged at the bottom of the receiving area. The nanofibers are arranged in the yarn in an ordered height orientation manner, and the mechanical property and the overall structural stability can be greatly improved under the condition of the same specification of yarn diameter.

Description

Technical Field

[0001] The utility model belongs to the technical field of tissue engineering and biomanufacturing materials, and in particular relates to a preparation device for a highly oriented electrostatically spun nanofiber absorbable surgical suture. Background Art

[0002] As we all know, medical materials possess high added value. However, current market conditions suggest that some high-end medical materials, largely reliant on imports, often command higher prices. For China, developing a domestically produced high-end medical materials industry and securing the corresponding independent intellectual property rights is imperative.

[0003] Surgical sutures are an indispensable type of medical equipment in surgical operations. They are special threads used in surgical operations or trauma treatment for ligation and hemostasis, suture and tissue suturing, and play a vital role in the early stages of wound healing. Common surgical sutures can be divided into non-absorbable sutures and absorbable sutures. The former needs to be removed after surgery to prevent tissue infection, while the latter can be degraded under the influence of the body environment without secondary treatment, which greatly improves the patient experience and recovery effect. It is a major trend in the development of surgical sutures in the future. In order to meet the needs of surgical operations or trauma treatment, surgical suture fibers need to have the following properties:

[0004] 1. Mechanical properties: Sutures need to have good mechanical properties, including sufficient strength and toughness to ensure that they will not break easily during surgery.

[0005] 2. Biocompatibility: Suture materials should be non-toxic and non-irritating, and be well compatible with human tissues to reduce inflammatory reactions and other adverse reactions.

[0006] 3. Absorbability: Sutures should gradually degrade over a period of time and eventually be absorbed by the human body, avoiding the need for secondary surgery to remove them.

[0007] 4. Controllable drug release: For drug-loaded sutures, it is necessary to be able to achieve controlled drug release and release different doses of drugs according to the different stages of wound healing.

[0008] A large number of articles have shown that nano-scale fiber sutures have biological properties that traditional micron-scale fiber sutures lack, namely, they simulate the structure of the extracellular matrix and provide a good biomimetic microenvironment for cell activity, thereby effectively promoting cell adhesion, proliferation, migration and differentiation, and achieving rapid healing and regeneration of damaged tissues or wounds. It can be seen that the yarn obtained by twisting ultrafine fibers prepared by electrospinning technology can be made into high-strength and high-toughness sutures with good mechanical properties and biocompatibility, which can meet the basic requirements of surgical sutures. At present, the technology for preparing surgical sutures based on nanofiber yarns has made great progress, such as the following patents:

[0009] CN116808278A discloses a drug-loaded suture and a preparation method thereof, comprising a substrate and a drug loaded on the surface of the substrate; the substrate has a skin-core structure, and the core layer of the substrate is polylactic acid filament; the skin layer of the substrate is a nanofiber membrane, and the nanofiber membrane is composed of polycaprolactone and polyglycolide; the mass percentage of the polyglycolide in the nanofiber membrane is 10 to 90%.

[0010] CN108193342A discloses a method for preparing drug-loaded nanofiber core-spun yarn for absorbable surgical sutures. Antibacterial and anti-inflammatory drugs are added to a hexafluoroisopropanol solution of chitosan, silk fibroin, and polylactic acid, and the mixture is uniformly mixed to form a spinning precursor; degradable surgical sutures are used as core yarns; and an electrostatic spinning method is used to prepare uniform and continuous drug-loaded nanofiber core-spun yarns. The utility model uses an electrostatic spinning method to prepare drug-loaded nanofiber core-spun yarns for surgical sutures. The process is simple, the operation is convenient, and the surface of the prepared yarn is uniformly coated with nanofibers.

[0011] CN115839028A discloses an antibacterial surgical suture, its preparation method, and application. This method uses amphiphilic molecules to encapsulate the fluorescent molecule DTPM, which exhibits aggregation-induced emission properties, to form AIE nanofibers. Maleic anhydride on the nanofiber surface reacts with thiol-reactive groups on cysteine ​​residues in the polypeptide sequence to introduce bioactive polypeptide chains onto the AIE nanofibers, producing AIE nanofibers with positively charged and hydrophilic surfaces. The surgical sutures are then plasma-etched to enhance their surface hydrophilicity. Finally, the polypeptide-functionalized AIE nanofibers are adsorbed onto the surfaces of four surgical sutures through hydrophilic and electrostatic interactions, ultimately producing surface-functionalized surgical sutures.

[0012] CN 116427042 A discloses a method and device for producing nanofiber yarn by centrifugal spinning. The method comprises: in the process of preparing nanofibers by centrifugal spinning, converting the horizontal outward airflow generated by the rotation of a spinning disk into a spiral airflow field to stretch and twist the spinning solution sprayed from a spinneret to produce the nanofiber yarn; the device comprises a spinning disk (4), a receiving device, a driving device and a self-twister (5); the spinning disk (4) comprises a vertical cylindrical barrel I, a spinning solution storage cavity is provided inside the cylindrical barrel I, a spinneret connected to the spinning solution storage cavity is provided on the circumference of the cylindrical barrel I, and the liquid discharge direction of the spinneret is horizontal; the self-twister (5) comprises a horizontal cylindrical tube I, a horizontal cylindrical tube II, a rolling ball (5-1), a fan blade (5-4), a wind collecting cover and a wind concentrating cover (5-2).

[0013] Although the above patented technologies provide a nanofiber surface for sutures, which can achieve the purpose of promoting cell adhesion, proliferation, migration and differentiation, they still use micron fibers as the core layer structure, or adsorption structure. Neither the skin-core design nor the nanofiber adsorption effect can ensure the stability of the overall structure of the suture. The nanofiber layer is easy to fall off, the nanofibers are arranged in a disorderly manner, and the adsorption amount is random. The method of collecting and twisting the yarn by centrifugal means, although the overall stability of the overall structure is improved compared with the skin-core structure, cannot guarantee the high orientation of the large number of nanofibers that make up the yarn. In other words, the nanofiber arrangement is also disorderly, and thus it cannot guarantee that its mechanical properties meet the requirements of surgical sutures. Moreover, the overall process flow of the above technologies is cumbersome and complicated, which is not conducive to industrial production. Therefore, how to prepare surgical sutures that meet actual use needs based on nanofiber structures, so that they have bionic characteristics while ensuring structural stability, so that the sutures can promote wound healing and assist in repair and regeneration during use, has become a difficult problem that technicians in the field of absorbable nanofiber surgical sutures urgently need to solve. Summary of the Invention

[0014] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is to provide a preparation device for highly oriented electrospun nanofiber absorbable surgical sutures, which can make the arrangement of nanofibers in yarns highly oriented and orderly, and greatly improve the mechanical properties and overall structural stability under the conditions of the same wire diameter.

[0015] In order to solve the above technical problems, the technical solution adopted by the present invention is: a preparation device for highly oriented electrospun nanofiber absorbable surgical sutures, comprising a spinning device with a liquid supply tank, a high-voltage power supply and an electrospinning nozzle, characterized in that: two conductive conveyor belts moving in opposite directions are arranged vertically and relatively parallel below the electrospinning nozzle for adhering and fixing the nanofibers formed by the jet stream and driving them to move downward, a receiving area for adhering nanofibers with consistent or similar arrangement directions is formed between the two conductive conveyor belts, a whipping area is formed between the electrospinning nozzle and the top of the conductive conveyor belt, and a collecting plate is provided at the bottom of the receiving area for intercepting the nanofibers adhered and fixed between the two conductive conveyor belts and flattening and accumulating them to form oriented nanofiber bundles. The invention also includes:

[0016] a cutting mechanism for cutting the formed oriented nanofiber bundle into strips of a certain width along the arrangement direction of the fibers;

[0017] a twisting mechanism for fixing one end of the cut strip and twisting the other end clockwise or counterclockwise to form a nanofiber line;

[0018] A stretching and shaping mechanism for thermally stretching nanofiber wires.

[0019] In the above-mentioned device for preparing highly oriented electrospun nanofiber absorbable surgical sutures, the collecting plate is disposed between the two conductive conveyor belts and is arranged perpendicular to the two conductive conveyor belts.

[0020] In the above-mentioned device for preparing highly oriented electrospun nanofiber absorbable surgical sutures, the width of the collecting plate is ≥ the width of the conductive conveyor belt, and the length of the collecting plate is ≤ the spacing between the two conductive conveyor belts.

[0021] The above-mentioned preparation device for highly oriented electrospun nanofiber absorbable surgical sutures, the conductive conveyor belt is 30 cm high and 10 cm wide, the distance between the two conductive conveyor belts is 20 cm, the conductive conveyor belt rotates at a speed of 60 cm / min, the collection plate is 18 cm long and 15 cm wide, and the distance between the electrospinning nozzle and the collection plate is 45 cm.

[0022] The advantages of the present invention's device for preparing highly oriented electrospun nanofiber absorbable surgical sutures are that it utilizes a pair of opposing, parallel conductive conveyor belts to collect the electrospun nanofibers. Limited by the width of the conductive conveyor belts, only nanofibers within a fixed tilt angle are retained between the two belts, while nanofibers with larger tilt angles are unable to adhere between the two belts and are discarded. A collection plate is positioned perpendicular to the conveyor belts. As the conveyor belts move toward each other, the nanofiber web remaining between them moves with the conveyor belts until intercepted by the collection plate. After a period of accumulation, a bundle of oriented nanofibers with consistent or similar fiber orientations forms on the collection plate. Subsequently, the two-dimensional nanofiber bundles are twisted into a compact three-dimensional linear structure as required. A hot stretching process is then used to further enhance the nanofiber orientation and crystallinity, resulting in a nanofiber surgical suture with excellent mechanical properties and biosafety. Thus, the electrospinning web-laying-twisting molding process and the hot stretching process produce a highly oriented, integrated nanofiber surgical suture with a complete and stable suture structure, a simple process flow, and flexible operation and control. The absorbable nanofiber surgical suture produced by this utility model breaks through the limitations of traditional micron fiber surgical sutures. It can align the nanofibers in the same direction and ensure that the mechanical properties meet the user's requirements, further improving the therapeutic effect of surgical sutures. This utility model is composed of an integrated nanofiber structure, and it is highly oriented, structurally uniform, has strong mechanical properties, is biodegradable, and has excellent biosafety, showing promising application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of a device for preparing absorbable surgical sutures according to the present invention;

[0024] Figure 2This is a schematic diagram of the preparation process of the highly oriented electrospun nanofiber absorbable surgical suture of the present invention;

[0025] Figure 3 A schematic structural diagram of a second absorbable surgical suture preparation device provided in Example 7;

[0026] Figure 4 A schematic structural diagram of a third absorbable surgical suture preparation device provided in Example 8;

[0027] Figure 5 The electron microscope photographs of the nanofiber and absorbable nanofiber suture prepared in Example 1 are shown;

[0028] Figure 6 This is an electron microscope photograph of the nanofiber and absorbable nanofiber suture prepared in Example 2;

[0029] Figure 7 This is an electron microscope photograph of the nanofiber and absorbable nanofiber suture prepared in Example 3;

[0030] Figure 8 This is an electron microscope photograph of the nanofiber and absorbable nanofiber suture prepared in Example 4;

[0031] Figure 9 This is an electron microscope photograph of the nanofiber and absorbable nanofiber suture prepared in Example 5;

[0032] Figure 10 This is an electron microscope photograph of the nanofiber and absorbable nanofiber suture prepared in Example 6. DETAILED DESCRIPTION

[0033] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0034] In this application, unless otherwise indicated, directional terms such as "upper" and "lower" generally refer to the upper and lower parts of the device in actual use or operation, specifically in the directions of the drawings in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "including" means "including but not limited to." Terms such as first, second, and third are used merely as designations and do not impose numerical requirements or establish a sequence. The term "plurality" means "two or more."

[0035] like Figure 1As shown, a device for preparing highly oriented electrospun nanofiber absorbable surgical sutures includes a spinning device having a liquid supply tank 1, a high-voltage power supply 2, and an electrospinning nozzle 3. Two conductive conveyor belts 5 are vertically arranged parallel to each other below the electrospinning nozzle 3, and are used to adhere and fix the nanofibers 4 formed by the jet stream and drive them downward. A receiving area 6 is formed between the two conductive conveyor belts 5 for adhering nanofibers 4 with consistent or similar alignment directions. A whipping area 7 is formed between the electrospinning nozzle 3 and the top of the conductive conveyor belt 5. Polymer droplets overcome surface tension to form the jet stream. During the jetting process, the solvent evaporates and eventually lands on the receiving device, that is, adheres to the conductive conveyor belt 5. The whipping area 7 provides a regulatory effect on the formation and adhesion of the nanofibers 4.

[0036] At the bottom of the receiving area 6, there is provided a collecting plate 8 for intercepting the nanofibers 4 adhered and fixed between the two conductive conveyor belts 5 and flattening and accumulating them to form an oriented nanofiber bundle. Specifically, the collecting plate 8 is arranged between the two conductive conveyor belts 5 and is arranged perpendicular to the two conductive conveyor belts 5. In order to maximize the collection efficiency of the nanofibers 4 and avoid missing the nanofibers 4 adhered to the edges of the two conductive conveyor belts, the width of the collecting plate 8 is ≥ the width of the conductive conveyor belt 5. In order to avoid affecting the normal operation of the two conductive conveyor belts 5 and at the same time improve the interception and collection efficiency, the length of the collecting plate 8 is ≤ the spacing between the two conductive conveyor belts 5. The specific dimensions of the present utility model are as follows: the height of the conductive conveyor belt 5 is 30 cm, the width is 10 cm, the spacing between the two conductive conveyor belts 5 is 20 cm, the rotation speed of the conductive conveyor belt 5 is 60 cm / min, the length of the collecting plate 8 is 18 cm, the width is 15 cm, and the spacing between the electrospinning nozzle 3 and the collecting plate 8 is 45 cm.

[0037] The device also includes: a cutting mechanism for cutting the formed oriented nanofiber bundle into strips of a certain width along the arrangement direction of the fibers; a twisting mechanism for fixing one end of the cut strip and twisting the other end clockwise or counterclockwise to form a nanofiber line; and a stretching and shaping mechanism for thermally stretching the nanofiber line. In the present invention, the twisting mechanism can be a digital yarn twist meter (Y331LN, China); the cutting mechanism can be a film cutting machine (ZX-1625VA, Zhuoxing); and the stretching and shaping mechanism can be a thermal stretching and shaping machine (TL018-1, Tianli Textile Machinery). Since the above mechanisms can all be replaced by existing equipment commonly used in the textile field and can all achieve the functions of each step of the present invention and achieve the desired technical effects, they will not be described in detail.

[0038] like Figure 2 As shown, a method for preparing a highly oriented electrospun nanofiber absorbable surgical suture comprises the following steps:

[0039] 1. Preparation of spinning solution

[0040] (1) dissolving a certain amount of absorbable polymer in an organic solvent, stirring the mixture under magnetic force and allowing it to stand for a certain period of time to prepare a spinning precursor of a certain concentration for later use; the absorbable polymer is any one of polycaprolactone, polyglycolide, poly-L-lactic acid, gelatin, and collagen, and the organic solvent is hexafluoroisopropanol;

[0041] 2. Preparation of Oriented Nanofiber Bundles

[0042] (2) spinning the spinning precursor obtained in step (1) through an electrospinning device under certain spinning conditions to adhere and fix the continuously produced nanofibers;

[0043] (3) screening and intercepting the nanofibers with the same or similar arrangement directions among the adhered and fixed nanofibers;

[0044] (4) The nanofibers obtained by screening and interception are flattened and accumulated to obtain an oriented nanofiber bundle horizontally spread along the radial direction of the nanofibers;

[0045] 3. Preparation of strips

[0046] (5) cutting the oriented nanofiber bundle obtained in step (4) into strips of a certain width along the arrangement direction of the fibers for later use;

[0047] 4. Preparation of Nanofiber Wires

[0048] (6) Fix one end of the cut strip and twist the other end clockwise or counterclockwise to form a nanofiber line;

[0049] 5. Hot drawing treatment

[0050] (7) hot-stretching the nanofiber wire obtained in step (6), and then naturally cooling it to room temperature;

[0051] (8) Obtain absorbable surgical sutures.

[0052] about Figure 2The absorbable nanofiber suture shown in the figure shows that the internal nanofibers are parallel to each other. The explanation is as follows: due to the effect of thermal stretching, the length of the nanofiber line increases, while the overall number of twist turns remains unchanged, resulting in the degree of twist per centimeter of fiber decreasing until it is negligible, making the angle between the fiber and the axis of the nanofiber line significantly reduced, and the fiber arrangement state with a high degree of orientation to the axis of the nanofiber line is presented in the local area; at the same time, the nanofibers are tightly hugged, forming a nanofiber linear structure with a smooth macroscopic surface and no obvious twist. Therefore, when one point of the absorbable nanofiber suture is magnified, although the fibers are parallel to each other, they still have a certain degree of twist. The thermal stretching step not only gives the absorbable nanofiber suture excellent mechanical properties, but also maximizes the high orientation of the nanofibers, meeting the basic performance requirements of the suture.

[0053] The nanofiber surgical suture produced by the present invention has a conveyor belt that selects the nanofibers, so only fibers with an inclination angle within a specified range are retained. These fibers are then accumulated layer by layer on a collection plate to form an oriented nanofiber bundle with a certain thickness. A torsion process can be used to transform the two-dimensional structure into a three-dimensional structure, laying the foundation for subsequent hot stretching. The hot stretching process can greatly promote the arrangement and formation of polymer macromolecular crystal regions, improve fiber crystallinity and orientation, and enable the suture, as a fiber aggregate, to achieve more excellent mechanical properties. Furthermore, during the hot stretching process, the inconsistently oriented nanofibers in the suture can be further adjusted to achieve a consistent orientation. The absorbable polymers described in the present invention include natural absorbable polymers and synthetic absorbable polymers, specifically including spinning solutions composed of poly(L-lactic acid) and poly(glycolide) in a solvent of dichloromethane / N,N-dimethylformamide (v / v = 3 / 1), or chitosan and polyamide in a solvent of formic acid, or polyacrylonitrile, polyurethane, or polydioxanone in a solvent of N,N-dimethylformamide, or polyvinyl alcohol or gelatin in a solvent of water (>80°C). The preparation process described in the present invention can be widely applied to various polymers suitable for electrospinning, such as polyacrylonitrile, polyamide, polyurethane, polyvinyl alcohol, polydioxanone, cellulose, and the like.

[0054] The present application will be described in detail below through specific examples. The following examples are only some examples of the present application and are not limitations of the present application.

[0055] Example 1

[0056] A method for preparing highly oriented electrospun nanofiber absorbable surgical sutures comprises the following steps:

[0057] 1. Preparation of spinning solution

[0058] (1) Dissolve a certain amount of polycaprolactone in hexafluoroisopropanol, stir magnetically and let it stand overnight to prepare a polycaprolactone spinning precursor with a concentration of 6%, and set aside;

[0059] 2. Preparation of Oriented Nanofiber Bundles

[0060] (2) spinning the spinning precursor prepared in step (1) through an electrospinning device under certain spinning conditions to adhere and fix the continuously produced nanofibers; the spinning conditions are: electrospinning voltage of ±12 kV, spinning precursor extrusion rate of 0.8 mL / h, conductive conveyor belt height of 30 cm, width of 10 cm, spacing between conductive conveyor belts of 20 cm, conductive conveyor belt rotation speed of 60 cm / min, collecting plate length of 18 cm, width of 15 cm, spacing between electrospinning nozzle and collecting plate of 45 cm, collecting time of 15 min, spinning temperature of 20°C, relative humidity of 35%;

[0061] (3) screening and intercepting the nanofibers with the same or similar arrangement directions among the adhered and fixed nanofibers;

[0062] (4) The nanofibers obtained by screening and interception are flattened and accumulated to obtain an oriented nanofiber bundle horizontally spread along the radial direction of the nanofibers;

[0063] 3. Preparation of strips

[0064] (5) Cut the oriented nanofiber bundle obtained in step (4) into strips with a width of 3 cm along the arrangement direction of the fibers for later use;

[0065] 4. Preparation of Nanofiber Wires

[0066] (6) Fix one end of the cut strip and twist the other end clockwise or counterclockwise to form a nanofiber line with a twisting degree of 7 turns / cm;

[0067] 5. Hot drawing treatment

[0068] (7) The nanofiber wire prepared in step (6) was subjected to hot stretching at a temperature of 60° C. and a hot stretching force of 20 N to twice its initial length, and then naturally cooled to room temperature;

[0069] (8) Obtain absorbable surgical sutures.

[0070] Example 2

[0071] The same parts as those in Example 1 will not be described in detail. The difference between this embodiment and Example 1 is that in step (1), a certain amount of polycaprolactone is dissolved in hexafluoroisopropanol to prepare a spinning solution precursor with a concentration of 9%.

[0072] Example 3

[0073] The same parts as those of Example 1-2 are not described in detail. The difference between this embodiment and Example 1-2 is that in step (1), a certain amount of polycaprolactone is dissolved in hexafluoroisopropanol to prepare a spinning solution precursor with a concentration of 12%.

[0074] Example 4

[0075] The same parts as those of Examples 1-3 are not described in detail. The difference between this embodiment and Examples 1-3 is that in step (1), a certain amount of polycaprolactone is dissolved in hexafluoroisopropanol to prepare a spinning solution precursor with a concentration of 15%.

[0076] Example 5

[0077] The same parts as those of Examples 1-4 are not described in detail. The difference lies in that in step (1), a certain amount of polycaprolactone is dissolved in hexafluoroisopropanol to prepare a spinning solution precursor with a concentration of 18%.

[0078] Example 6

[0079] The same parts as those of Examples 1-5 are not described again. The difference lies in that: in step (1), a certain amount of polycaprolactone is dissolved in hexafluoroisopropanol to prepare a spinning solution precursor with a concentration of 21%.

[0080] Example 7

[0081] like Figure 3 As shown, this embodiment provides a second device for preparing highly oriented electrospun nanofiber absorbable surgical sutures. Figure 1 The similarities will not be repeated here. The difference lies in that a collecting conveyor belt 9 is provided at the bottom of the receiving area 6 for intercepting the nanofibers adhered and fixed between the two conductive conveyor belts 5 and flattening and accumulating them to form oriented nanofiber bundles. The collecting conveyor belt 9 can continuously and automatically output the oriented nanofiber bundles formed by intercepting and flattening the accumulated stacking from the receiving area 6, thereby achieving the purpose of automatic output of the oriented nanofiber bundles, reducing the labor intensity of workers, improving the level of automation, and being suitable for industrial applications.

[0082] Example 8

[0083] like Figure 4 As shown, this embodiment provides a third device for preparing highly oriented electrospun nanofiber absorbable surgical sutures. Figure 1 、 Figure 3 The similarities will not be repeated here, and the differences are as follows: a collecting conveyor belt 10 is provided at the bottom of the receiving area 6 for intercepting and flattening the nanofibers adhered and fixed between the two conductive conveyor belts 5 to form an oriented nanofiber bundle, and a second conveyor belt 11 is connected to the collecting conveyor belt 10 for outputting the intercepted and flattened accumulated nanofibers to form an oriented nanofiber bundle, and realizing continuous overlap of the oriented nanofiber bundles along the fiber length direction. The output end of the second conveyor belt is provided with a third conveyor belt 12 associated with a cutting mechanism for performing the cutting process. The second conveyor belt 11 is tilted and tilted downward from the receiving area 6 to facilitate the continuous output of the oriented nanofibers along their length direction. During the output process, it can achieve the purpose of automatically overlapping the oriented nanofiber bundles, making it possible to prepare continuous absorbable surgical sutures. It has a simple structure and low cost, making it suitable for industrial applications.

[0084] This utility model utilizes an electrospinning-laying-torsion forming process, followed by a heat-drawing process, to produce absorbable nanofiber surgical sutures under different process parameters. The test results of their mechanical properties, surface morphology, and biocompatibility are as follows:

[0085] 1. Mechanical properties and surface morphology

[0086] Examples 1-6 respectively obtained 6 different concentrations (6% PCL, 9% PCL, 12% PCL, 15% PCL, 18% PCL, 21% PCL) of PCL absorbable nanofiber surgical sutures. The morphology and structure were observed using a scanning electron microscope (TESCAN VEGA3, Czech Republic). In order to improve the conductivity of the suture, gold was sprayed on the surface of the sample for 160s. The average wire diameter and average fiber diameter were measured using ImageJ software (National Institutes of Health, USA). 100 positions were randomly selected for each sample for measurement and statistics. Its surface morphology Figure 5-10 The fiber diameter and suture diameter were measured, and the results are shown in Table 1. Analysis shows that the fibers in the obtained surgical sutures are nanofibers, and the nanofiber morphology is uniform without obvious beading. When the PCL concentration reaches 12%, the fibers are highly oriented along the suture axis, and the suture structure is uniform and smooth. With the increase of polymer concentration, the fiber diameter and wire diameter gradually increase. XRD analysis was performed using a Japanese Rigaku Ultima IV type Cu Kα radiation source with a scanning rate of 8° (2θ) / min and a scanning range of 5° to 60° (2θ). The crystallinity of the six PCL nanofiber surgical sutures was measured to be 43.6%, 50.3%, 54.6%, 54.3%, 55.6%, and 57.3%, respectively.

[0087] Table 1 Fiber diameter and wire diameter of six PCL nanofiber surgical sutures

[0088] sample Wire diameter (μm) Fiber diameter (nm) 6% PCL 272.5±1.5 629.3±53.5 9% PCL 379.7±1.5 735.7±25.0 12% PCL 418.1±2.3 828.4±19.4 15% PCL 446.6±5.4 887.3±2.5 18% PCL 510.2±3.5 895.1±1.3 21% PCL 640.0±5.1 902.5±1.6

[0089] The mechanical properties of six PCL nanofiber surgical sutures were tested according to YY 1116-2020, and the results are shown in Table 2.

[0090] Table 2 Mechanical properties of six PCL nanofiber surgical sutures

[0091] sample Breaking load (N) Breaking strength (MPa) Elongation at break (%) 6% PCL 4.0±0.2 69.3±9.1 152.2±11.0 9% PCL 21.5±0.8 190.0±8.0 257.2±29.5 12% PCL 26.6±0.2 193.4±3.2 292.2±8.6 15% PCL 28.9±8.9 186.2±15.5 269.1±33.4 18% PCL 27.4±4.6 130.1±10.4 315.8±24.1 21% PCL 34.7±0.9 107.8±3.0 276.5±25.2

[0092] 2. Biocompatibility

[0093] The obtained PCL nanofiber surgical sutures were subjected to an in vitro cytotoxicity test according to GBT 16886.5-2017, and the measured fibroblast survival rates are shown in Table 3, demonstrating that all the samples were non-cytotoxic.

[0094] Table 3 Cytocompatibility of six PCL nanofiber surgical sutures

[0095] sample Day 1 Day 3 6% PCL 99.8％ 99.5％ 9% PCL 99.7％ 99.5％ 12% PCL 99.9％ 99.4％ 15% PCL 99.6％ 99.4％ 18% PCL 99.8％ 98.8％ 21% PCL 99.9％ 99.4％

[0096] From the above experimental results, it can be seen that by comparing the fiber diameter, wire diameter, mechanical properties and cytotoxicity of the six PCL nanofiber surgical sutures, it can be concluded that:

[0097] The absorbable nanofiber surgical suture provided by the present invention has a uniform and smooth nanoscale appearance, excellent mechanical properties, and good cell compatibility. As the PCL concentration increases, the fiber diameter and wire diameter increase slightly, the crystallinity increases, and the breaking strength increases significantly. This is because thermal stretching can effectively promote the formation of crystal regions in high molecular polymers, increase the crystallinity of the suture, and greatly improve the fiber orientation, which is manifested as an improvement in the mechanical properties of the suture. Taking all factors into consideration, the absorbable nanofiber suture finally obtained by selecting the 12% PCL concentration adopted in Example 3 of the present invention has the best overall performance.

[0098] Using electrospinning and web laying technology, the chaotic nanofibers can be spread and collected in a specific direction. Using a strip twisting method, two-dimensional nanofiber bundles can be quickly and efficiently converted into three-dimensional nanofiber threads. The subsequent hot stretching process further improves the structure and properties of the three-dimensional nanofiber threads, reducing the diameter of the nanofiber suture, increasing its crystallinity and orientation, and enhancing its mechanical properties. The preparation process of this utility model produces a complete and continuous nanofiber suture with tightly bonded fibers. The suture structure is stable and difficult to separate, with excellent mechanical properties and good biosafety.

[0099] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should fall within the scope of protection of the present invention.

Claims

1. A device for preparing highly oriented electrospun nanofiber absorbable surgical sutures, comprising a spinning device having a liquid supply tank, a high-voltage power supply, and an electrospinning nozzle, characterized by: Two conductive conveyor belts are arranged vertically and parallelly below the electrospinning nozzle and are used to adhere and fix the nanofibers formed by the jet stream and drive them to move downward. A receiving area for adhering nanofibers with consistent or similar arrangement directions is formed between the two conductive conveyor belts. A whipping area is formed between the electrospinning nozzle and the top of the conductive conveyor belt. A collecting plate is provided at the bottom of the receiving area for intercepting the nanofibers adhered and fixed between the two conductive conveyor belts and flattening and accumulating them to form oriented nanofiber bundles. The invention also includes: a cutting mechanism for cutting the formed oriented nanofiber bundle into strips of a certain width along the arrangement direction of the fibers; a twisting mechanism for fixing one end of the cut strip and twisting the other end clockwise or counterclockwise to form a nanofiber line; A stretching and shaping mechanism for thermally stretching nanofiber wires.

2. The device for preparing highly oriented electrospun nanofiber absorbable surgical suture according to claim 1, characterized in that: The collecting plate is arranged between the two conductive conveyor belts and is vertically arranged with respect to the two conductive conveyor belts.

3. The device for preparing highly oriented electrospun nanofiber absorbable surgical suture according to claim 1, characterized in that: The width of the collecting plate is greater than or equal to the width of the conductive conveyor belt, and the length of the collecting plate is less than or equal to the spacing between the two conductive conveyor belts.

4. The device for preparing highly oriented electrospun nanofiber absorbable surgical suture according to claim 1, characterized in that: The height of the conductive conveyor belt is 30 cm, the width is 10 cm, the distance between the two conductive conveyor belts is 20 cm, the rotation speed of the conductive conveyor belt is 60 cm / min, the length of the collecting plate is 18 cm, the width is 15 cm, and the distance between the electrospinning nozzle and the collecting plate is 45 cm.

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