A method for preparing an antibacterial suture with a blunt barb

Abstract

The application discloses a preparation method of an antibacterial suture with passivated barbs, and relates to the technical field of medical sutures. The method comprises the following steps: preparing a core layer and a shell layer spinning solution, and forming a core-shell structure monofilament through coaxial electrospinning; adopting femtosecond laser precision machining to passivate the barbs, and locally thinning the barb area, and then coating an antibacterial coating liquid, vacuum drying, ethylene oxide sterilization and heat setting to obtain the antibacterial suture with passivated barbs. The antibacterial coating liquid is prepared from chitosan, an acetic acid aqueous solution, an antibacterial component and a crosslinking agent. Through the synergistic effect of the core-shell structure and the double antibacterial system, the application takes into account long-acting antibacterial property and mechanical property; the femtosecond laser machining optimizes the barb morphology and reduces tissue damage; and the material and process regulation achieve the balance of biocompatibility, operation performance and degradation rate, and is suitable for clinical surgical wound suturing, and can reduce the risk of infection and the pain of patients.

Description

Technical Field

[0001] This invention relates to the field of medical suture technology, specifically to a method for preparing an antibacterial suture with blunted barbs. Background Technology

[0002] In clinical surgery, sutures are an indispensable basic material for closing wounds and connecting tissues. Traditional smooth sutures rely on knotting for fixation, which is cumbersome and can lead to poor wound closure due to loose knots. To address this, sutures with barbed structures have been developed. These sutures achieve knotless fixation through mechanical interlocking between the barbs and tissue, simplifying surgical procedures and providing a more uniform tension distribution. However, existing barbed sutures still have limitations in the design and manufacturing precision of the barbs. Mechanically cut or molded barbs often have sharp edges and poor morphological consistency, easily causing cutting damage to surrounding soft tissues during puncture and anchoring, leading to additional inflammatory responses. Furthermore, achieving an ideal balance between anchoring stability and the degree of tissue damage is difficult.

[0003] On the other hand, surgical site infection is a common postoperative complication, making the development of antibacterial sutures crucial for infection prevention. Currently, most common antibacterial sutures employ blending or surface adsorption to load antibacterial agents. While these methods impart some antibacterial properties, they often suffer from problems such as rapid release of antibacterial components, narrow antibacterial spectrum, and insufficient long-term effectiveness. Especially for absorbable sutures, maintaining an effective and stable antibacterial concentration throughout the entire degradation cycle, while avoiding toxic side effects or drug resistance risks due to sudden antibacterial release, remains a significant technical challenge.

[0004] Furthermore, with the development of materials science, absorbable polymer materials have become the mainstream choice in the field of sutures. Ideal absorbable sutures need to maintain sufficient mechanical strength in vivo to support wound healing, subsequently degrade smoothly at a controllable rate, and the degradation products should have good biocompatibility. In existing technologies, sutures prepared from single materials or simple blends often fail to simultaneously meet multiple requirements such as high strength, flexibility, controllable degradation, and surface functionalization. Especially for sutures with both barbed structures and antibacterial functions, how to achieve synergistic optimization of mechanical properties, antibacterial efficacy, handling feel, and biocompatibility through innovation in material systems and preparation processes is a key problem that urgently needs to be solved in this technological field. Summary of the Invention

[0005] To address the problems mentioned in the background section, this invention provides a method for preparing an antibacterial suture with blunted barbs.

[0006] This invention provides a method for preparing an antibacterial suture with blunted barbs, comprising the following steps:

[0007] Step S1: Add polylactic acid-glycolic acid copolymer, polycaprolactone and polyhexamethylene biguanide to dichloromethane-dimethylformamide mixed solvent, stir to dissolve, and obtain core layer spinning solution;

[0008] Step S2: Add the polylactic acid-glycolic acid copolymer to the dichloromethane-dimethylformamide mixed solvent, stir to dissolve, and obtain the shell spinning solution;

[0009] Step S3: The core spinning solution and the shell spinning solution are spun using a coaxial electrospinning process to obtain core-shell structured monofilaments;

[0010] Step S4: Use femtosecond laser precision machining to form a blunt barb with a preset radius of curvature and tilt angle. Then, use femtosecond laser micro-etching process to locally thin the barb area to obtain a core-shell antibacterial monofilament intermediate with a thinned shell and blunt barbs.

[0011] Step S5: Immerse the core-shell antibacterial monofilament intermediate with thinned shell and passivated barbs into the antibacterial coating liquid, apply it using the dip-lift method, and then vacuum dry it to obtain the pre-finished core-shell suture with passivated barbs.

[0012] Step S6: Place the pre-finished blunt barbed core-shell suture in an ethylene oxide sterilizer for sterilization. After sterilization, heat set the suture to obtain an antibacterial suture with blunt barbs.

[0013] Furthermore, the preparation method of the antibacterial coating liquid includes the following steps:

[0014] Chitosan was dissolved in an aqueous acetic acid solution and stirred until completely dissolved to obtain a chitosan solution. Polyhexamethylene biguanide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were added and stirred until uniform. N-hydroxysuccinimide was added and stirred at room temperature for 2-3 hours. After standing to remove bubbles, an antibacterial coating solution was obtained.

[0015] Further, the weight parts of each raw material in the antibacterial coating liquid are as follows: 10-30 parts chitosan, 70-90 parts aqueous acetic acid solution, 2-8 parts polyhexamethylene biguanide, 1-5 parts 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, and 0.5-3 parts N-hydroxysuccinimide; the mass fraction of acetic acid in the aqueous acetic acid solution is 1%-2%.

[0016] Further, in step S1, the weight proportions of each raw material in the core spinning solution are: 50-70 parts of polylactic acid-glycolic acid copolymer, 30-50 parts of polycaprolactone, 0.5-2 parts of polyhexamethylene biguanide, and 200-300 parts of dichloromethane-dimethylformamide mixed solvent.

[0017] Further, in step S2, the weight proportions of each raw material in the shell spinning solution are: 40-60 parts of polylactic acid-glycolic acid copolymer and 150-250 parts of dichloromethane-dimethylformamide mixed solvent.

[0018] Furthermore, in steps S1 and S2, the volume ratio of dichloromethane to dimethylformamide in the dichloromethane-dimethylformamide mixed solvent is 3-5:1.

[0019] Furthermore, in step S3, the mass ratio of the core spinning solution to the shell spinning solution is 1:1.2-1.5.

[0020] Furthermore, the parameters of the coaxial electrospinning process in step S3 are: spinning voltage 15kV-20kV, receiving distance 18cm-22cm, and feed speed 0.5mL / h-1.5mL / h; the diameter of the core-shell structure monofilament is 0.1mm-0.2mm.

[0021] Furthermore, the parameters for femtosecond laser precision machining of passivated barbs in step S4 are: wavelength 1030nm-1080nm, pulse width 80fs-120fs, power 40mW-60mW; the radius of curvature of the passivated barbs is 0.05mm-0.1mm, and the tilt angle is 30°-45°.

[0022] The parameters of the femtosecond laser micro-etching process in step S4 are: power 25mW-35mW, scanning speed 400μm / s-600μm / s, and the thickness of the barbed area is reduced to 15%-25% of the original thickness.

[0023] Furthermore, the process parameters for the immersion-lifting method in step S5 are: lifting speed 4mm / s-6mm / s, immersion time 10s-20s; and vacuum drying conditions are: temperature 55℃-65℃, vacuum degree 0.08MPa-0.1MPa, and drying time 10h-14h.

[0024] Furthermore, the conditions for ethylene oxide sterilization in step S6 are: temperature 50℃-60℃, humidity 55%-65%, sterilization time 3h-5h; the conditions for heat setting are: temperature 35℃-45℃, tension 0.4N-0.6N, setting time 1h-2h.

[0025] The beneficial effects of this invention are:

[0026] 1. This invention achieves long-lasting stability of antibacterial efficacy and synergistic improvement of mechanical properties through the design of a core-shell structure combined with a dual antibacterial system. The introduction of polycaprolactone and polyhexamethylene biguanide in the core spinning solution enhances the flexibility and antibacterial ability of the suture; the polylactic acid-glycolic acid copolymer in the shell spinning solution plays a protective and sustained-release role, preventing premature loss of antibacterial components. A cross-linked and cured chitosan-based antibacterial coating is further applied to the surface, forming an internal and external antibacterial barrier, thereby significantly inhibiting various common pathogens while maintaining good mechanical strength and controllable degradation of the suture.

[0027] 2. This invention employs femtosecond laser precision machining and femtosecond laser micro-etching processes to achieve precise forming and performance optimization of the barb structure. Using a femtosecond laser, blunted barbs with precisely controllable curvature radius and tilt angle can be processed on the surface of the core-shell monofilament, ensuring consistent barb shape and smooth edges. Furthermore, the femtosecond laser is used to locally thin the barb area, enabling the barb to maintain sufficient anchoring force while possessing suitable flexibility, thereby reducing tissue damage during puncture and improving the safety and smoothness of the suturing operation.

[0028] 3. This invention balances the biocompatibility, operability, and degradation compatibility of the suture through material selection and process control. The entire preparation process uses biodegradable polymer materials, combined with ethylene oxide sterilization and heat setting treatment, resulting in a final product exhibiting low hemolysis and mild tissue reaction. After thinning and coating modification, the barbs are firmly anchored in the tissue and easily penetrate it, achieving a suture effect that is easy to insert but difficult to withdraw. At the same time, the core-shell structure and coating system synergistically regulate the degradation rate, allowing the suture to maintain its functional integrity during the wound healing period, followed by stable degradation, meeting clinical use requirements. Detailed Implementation

[0029] To make the implementation methods of this application easier to understand, the application will be described in detail below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not limited to the application scope of this application.

[0030] The polylactic acid-glycolic acid copolymer used in this invention was purchased from Jilin Zhongkekang Technology Co., Ltd.

[0031] The hexamethylene biguanide used in this invention has the CAS number 57029-18-2 and an active ingredient content of 20%, and was purchased from Jinan Weizhen Chemical Co., Ltd.

[0032] The polycaprolactone used in this invention has the CAS number 24980-41-4 and was purchased from Hubei Watson Chemical Technology Co., Ltd.

[0033] Example 1:

[0034] A method for preparing an antibacterial suture with blunted barbs includes the following preparation steps:

[0035] Preparation of antibacterial coating liquid:

[0036] Weigh out 10 parts of chitosan, 70 parts of 1% acetic acid aqueous solution, 2 parts of polyhexamethylene biguanide, 1 part of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, and 0.5 parts of N-hydroxysuccinimide. Add chitosan to the acetic acid aqueous solution and stir until completely dissolved to obtain a chitosan solution. Add polyhexamethylene biguanide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride to the chitosan solution and stir to mix evenly. Add N-hydroxysuccinimide and stir to react at room temperature for 2 hours. After the reaction is completed, let stand for 30 minutes to remove bubbles to obtain an antibacterial coating liquid.

[0037] Preparation of antibacterial sutures with blunted barbs:

[0038] Step S1: Weigh 50 parts of polylactic acid-glycolic acid copolymer, 30 parts of polycaprolactone, 0.5 parts of polyhexamethylene biguanide, and 200 parts of chloromethane-dimethylformamide mixed solvent (dichloromethane to dimethylformamide volume ratio of 5:1); add polylactic acid-glycolic acid copolymer, polycaprolactone, and polyhexamethylene biguanide to the chloromethane-dimethylformamide mixed solvent, stir to dissolve, and obtain the core layer spinning solution;

[0039] Step S2: Weigh 40 parts of polylactic acid-glycolic acid copolymer and 150 parts of chloromethane-dimethylformamide mixed solvent (dichloromethane to dimethylformamide volume ratio of 5:1); add the polylactic acid-glycolic acid copolymer to the chloromethane-dimethylformamide mixed solvent, stir to dissolve, and obtain shell spinning solution;

[0040] Step S3: Inject the core spinning solution and shell spinning solution into the inner and outer injectors of the coaxial electrospinning device at a mass ratio of 1:1.2. Set the spinning process parameters as follows: spinning voltage 15kV, receiving distance 18cm, core spinning solution feed rate 0.5mL / h, shell spinning solution feed rate 0.5mL / h, spinning ambient temperature 20℃, ambient humidity 30%. Perform coaxial electrospinning and collect core-shell structure monofilaments with a diameter of 0.1mm.

[0041] Step S4: Fix the core-shell structured monofilament obtained in step S3 on the processing table and place it in a clean air environment. Use a femtosecond laser to perform precision processing on it. Set the femtosecond laser parameters as follows: wavelength 1030nm, pulse width 80fs, power 40mW, and scanning spacing 5μm. Process the core-shell structured monofilament to form a passivated barb with a radius of curvature of 0.05mm, an inclination angle of 30°, a length of 0.1mm, and a spacing of 0.5mm. Use a femtosecond laser micro-etching process to locally thin the barb area. Set the etching parameters as follows: power 25mW, scanning speed 400μm / s, and etching area diameter of 0.3mm. Reduce the thickness of the barb area to 15% of the original thickness to obtain a core-shell antibacterial monofilament intermediate with thinned shell and passivated barbs.

[0042] Step S5: The core-shell antibacterial monofilament intermediate with thinned shell and passivated barbs is completely immersed in the antibacterial coating solution and coated using the dip-lift method, with an immersion time of 10s and a lifting speed of 4mm / s. After coating, it is placed in a vacuum drying oven and dried for 10h at a temperature of 55℃ and a vacuum degree of 0.08MPa, with ventilation for 5min every 3h during the drying process, to obtain the pre-finished core-shell suture with passivated barbs.

[0043] Step S6: Place the pre-finished core-shell suture with passivated barbs into an ethylene oxide sterilizer for sterilization. Set the sterilization temperature to 50℃, humidity to 55%, ethylene oxide concentration to 600mg / L, and sterilization time to 3h. Then, perform heat setting on the sterilized suture. Set the heat setting temperature to 35℃, tension to 0.4N, and setting time to 1h. After setting, allow it to cool naturally to room temperature. This will result in an antibacterial suture with passivated barbs.

[0044] Example 2:

[0045] A method for preparing an antibacterial suture with blunted barbs includes the following preparation steps:

[0046] Preparation of antibacterial coating liquid:

[0047] Weigh out 20 parts of chitosan, 80 parts of 1.5% acetic acid aqueous solution, 5 parts of polyhexamethylene biguanide, 3 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, and 2 parts of N-hydroxysuccinimide. Add chitosan to the acetic acid aqueous solution and stir until completely dissolved to obtain a chitosan solution. Add polyhexamethylene biguanide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride to the chitosan solution and stir to mix evenly. Add N-hydroxysuccinimide and stir at room temperature for 2.5 minutes. After the reaction is complete, let stand for 45 minutes to remove bubbles to obtain an antibacterial coating liquid.

[0048] Preparation of antibacterial sutures with blunted barbs:

[0049] Step S1: Weigh 60 parts of polylactic acid-glycolic acid copolymer, 40 parts of polycaprolactone, 1.5 parts of polyhexamethylene biguanide, and 250 parts of dichloromethane-dimethylformamide mixed solvent (dichloromethane to dimethylformamide volume ratio of 4:1); add polylactic acid-glycolic acid copolymer, polycaprolactone, and polyhexamethylene biguanide to the dichloromethane-dimethylformamide mixed solvent, stir to dissolve, and obtain the core layer spinning solution;

[0050] Step S2: Weigh 50 parts of polylactic acid-glycolic acid copolymer and 200 parts of dichloromethane-dimethylformamide mixed solvent (dichloromethane to dimethylformamide volume ratio of 4:1); add the polylactic acid-glycolic acid copolymer to the dichloromethane-dimethylformamide mixed solvent, stir to dissolve, and obtain shell spinning solution;

[0051] Step S3: Inject the core spinning solution and shell spinning solution into the inner and outer injectors of the coaxial electrospinning device at a mass ratio of 1:1.4. Set the spinning process parameters as follows: spinning voltage 18kV, receiving distance 20cm, core spinning solution feed rate 1.0mL / h, shell spinning solution feed rate 1.0mL / h, spinning ambient temperature 23℃, ambient humidity 40%. Perform coaxial electrospinning and collect core-shell structure monofilaments with a diameter of 0.15mm.

[0052] Step S4: Fix the core-shell structure monofilament on the processing table and place it in a clean air environment. Use a femtosecond laser to perform precision processing on it. Set the femtosecond laser parameters as follows: wavelength 1050nm, pulse width 100fs, power 50mW, and scanning spacing 8μm. Process the core-shell structure monofilament to form passivated barbs with a radius of curvature of 0.08mm, an inclination angle of 37°, a length of 0.15mm, and a spacing of 0.8mm. Use a femtosecond laser micro-etching process to locally thin the barb area. Set the etching parameters as follows: power 30mW, scanning speed 500μm / s, and etching area diameter 0.4mm. Reduce the thickness of the barb area to 20% of the original thickness to obtain a core-shell antibacterial monofilament intermediate with thinned shell passivated barbs.

[0053] Step S5: The core-shell antibacterial monofilament intermediate with thinned shell and passivated barbs is completely immersed in the antibacterial coating solution and coated using the dip-lift method, with an immersion time of 15s and a lifting speed of 5mm / s; after coating, it is placed in a vacuum drying oven and dried for 12h at a temperature of 60℃ and a vacuum degree of 0.09MPa to obtain the pre-finished core-shell suture with passivated barbs;

[0054] Step S6: Place the pre-finished core-shell suture with passivated barbs into an ethylene oxide sterilizer for sterilization. Set the sterilization temperature to 55℃, humidity to 60%, ethylene oxide concentration to 700mg / L, and sterilization time to 4h. Then, perform heat setting on the sterilized suture. Set the heat setting temperature to 40℃, tension to 0.5N, and setting time to 1.5h. After setting, allow it to cool naturally to room temperature to obtain an antibacterial suture with passivated barbs.

[0055] Example 3:

[0056] A method for preparing an antibacterial suture with blunted barbs includes the following preparation steps:

[0057] Preparation of antibacterial coating liquid:

[0058] Weigh out 30 parts of chitosan, 90 parts of 2% acetic acid aqueous solution, 8 parts of polyhexamethylene biguanide, 5 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, and 3 parts of N-hydroxysuccinimide. Add chitosan to the acetic acid aqueous solution and stir until completely dissolved to obtain a chitosan solution. Add polyhexamethylene biguanide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride to the chitosan solution and stir to mix evenly. Add N-hydroxysuccinimide and stir to react at room temperature for 3 hours. After the reaction is completed, let stand for 60 minutes to remove bubbles to obtain an antibacterial coating liquid.

[0059] Preparation of antibacterial sutures with blunted barbs:

[0060] Step S1: Weigh 70 parts of polylactic acid-glycolic acid copolymer, 50 parts of polycaprolactone, 2 parts of polyhexamethylene biguanide, and 300 parts of dichloromethane-dimethylformamide mixed solvent (dichloromethane to dimethylformamide volume ratio of 3:1); add polylactic acid-glycolic acid copolymer, polycaprolactone, and polyhexamethylene biguanide to the dichloromethane-dimethylformamide mixed solvent, stir to dissolve, and obtain the core layer spinning solution;

[0061] Step S2: Weigh 60 parts of polylactic acid-glycolic acid copolymer and 250 parts of dichloromethane-dimethylformamide mixed solvent (dichloromethane to dimethylformamide volume ratio of 3:1); add the polylactic acid-glycolic acid copolymer to the dichloromethane-dimethylformamide mixed solvent, stir to dissolve, and obtain shell spinning solution;

[0062] Step S3: Inject the core spinning solution and shell spinning solution into the inner and outer injectors of the coaxial electrospinning device at a mass ratio of 1:1.5. Set the spinning process parameters as follows: spinning voltage 20kV, receiving distance 22cm, core spinning solution feed rate 1.5mL / h, shell spinning solution feed rate 1.5mL / h, spinning ambient temperature 25℃, ambient humidity 50%. Perform coaxial electrospinning and collect core-shell structure monofilaments with a diameter of 0.2mm.

[0063] Step S4: Fix the core-shell structure monofilament on the processing table and place it in a clean air environment. Use a femtosecond laser to perform precision processing on it. Set the femtosecond laser parameters as follows: wavelength 1080nm, pulse width 120fs, power 60mW, and scanning spacing 10μm. Process the core-shell structure monofilament to form passivated barbs with a radius of curvature of 0.1mm, an inclination angle of 45°, a length of 0.2mm, and a spacing of 1mm. Use a femtosecond laser micro-etching process to locally thin the barb area. Set the etching parameters as follows: power 35mW, scanning speed 600μm / s, and etching area diameter 0.5mm. Reduce the thickness of the barb area to 25% of the original thickness to obtain a core-shell antibacterial monofilament intermediate with thinned shell and passivated barbs.

[0064] Step S5: The core-shell antibacterial monofilament intermediate with thinned shell and passivated barbs is completely immersed in the antibacterial coating liquid and coated using the dip-lift method, with the dip time set to 20s and the lift speed to 6mm / s; after coating, it is placed in a vacuum drying oven and dried for 14h at a temperature of 65℃ and a vacuum degree of 0.1MPa to obtain the pre-finished core-shell suture with passivated barbs;

[0065] Step S6: Place the pre-finished core-shell suture with passivated barbs into an ethylene oxide sterilizer for sterilization. Set the sterilization temperature to 60℃, humidity to 65%, ethylene oxide concentration to 800mg / L, and sterilization time to 5h. Then, perform heat setting on the sterilized suture. Set the heat setting temperature to 45℃, tension to 0.6N, and setting time to 2h. After setting, allow it to cool naturally to room temperature. This will result in an antibacterial suture with passivated barbs.

[0066] Comparative Example 1

[0067] Compared with Example 1, this comparative example does not use the coaxial electrospinning process, but instead uses a single-layer electrospinning process. The core layer spinning solution is not prepared, and only the shell layer spinning solution prepared in step S2 is used for single-layer electrospinning. The remaining steps and parameters are the same, and will not be repeated in this comparative example. Finally, an antibacterial suture with passivated barbs is obtained.

[0068] The specific operating steps of the single-layer electrospinning process are as follows:

[0069] The shell spinning solution prepared in step S1 was injected into the syringe of the electrospinning equipment. The spinning process parameters were set as follows: spinning voltage 15kV, receiving distance 18cm, feed speed 0.5mL / h, spinning ambient temperature 20℃, and ambient humidity 30%. Single-layer electrospinning was carried out, and a single-layer monofilament with a diameter of 0.1mm was collected.

[0070] Comparative Example 2

[0071] Compared with Example 1, this comparative example does not use coaxial electrospinning, but instead uses single-layer electrospinning. The shell spinning solution is not prepared, and only the core spinning solution prepared in step S1 is used for single-layer electrospinning. The other steps and parameters are the same, and will not be repeated in this comparative example. Finally, an antibacterial suture with passivated barbs is obtained.

[0072] The specific operating steps of the single-layer electrospinning process are as follows:

[0073] The core spinning solution prepared in step S1 was injected into the syringe of the electrospinning equipment. The spinning process parameters were set as follows: spinning voltage 15kV, receiving distance 18cm, feed speed 0.5mL / h, spinning ambient temperature 20℃, and ambient humidity 30%. Single-layer electrospinning was carried out, and a single-layer monofilament with a diameter of 0.1mm was collected.

[0074] Comparative Example 3

[0075] Compared with Example 1, the femtosecond laser micro-etching step is omitted in step S4 of this comparative example. The shell thickness of the barb region remains unchanged. The remaining steps and parameters are the same. This comparative example will not be repeated. Finally, an antibacterial suture with passivated barbs is obtained.

[0076] Performance testing

[0077] The performance of the antibacterial sutures with blunted barbs prepared in Examples 1-3 and the antibacterial sutures with blunted barbs prepared in Comparative Examples 1-3 were tested, and the results are recorded in Table 1.

[0078] Detection method for antibacterial sutures with blunted barbs:

[0079] Antibacterial performance testing: Referring to GB / T 20944.3-2008, three common clinical pathogens were selected as indicator strains for testing: Gram-positive Staphylococcus aureus (ATCC 6538), Gram-negative Escherichia coli (ATCC 25922), and Pseudomonas aeruginosa (ATCC 27853), to comprehensively evaluate the broad-spectrum antibacterial efficacy of the sutures. The antibacterial sutures with blunted barbs prepared in Examples 1-3 and the antibacterial sutures with blunted barbs prepared in Comparative Examples 1-3 were cut into 10mm segments and immersed in 50mL of a 10% concentration of antibacterial agent. 6In bacterial suspensions at CFU / mL (containing Staphylococcus aureus (Gram-positive), Escherichia coli (Gram-negative), and Pseudomonas aeruginosa (Gram-negative) suspensions respectively), after incubation at 37°C with shaking for 24 hours, the bacterial suspensions were serially diluted and plated on agar plates. The number of surviving colonies was counted to obtain the colony count of the experimental group. This was compared with the blank control group using the formula: Calculate the antibacterial rate.

[0080] Mechanical performance testing: Referring to YY 1116-2020, an Instron 5967 universal testing machine was used. The antibacterial sutures with blunted barbs prepared in Examples 1-3 and Comparative Examples 1-3 were used as specimens. Both ends were fixed with special clamps. The initial gauge length was set to 100 mm. Uniaxial tensile tests were carried out at a constant tensile speed of 50 mm / min. The load-displacement curves were recorded in real time. The tensile strength (unit: MPa) of each suture was obtained by calculating the ratio of the maximum tensile load to the original cross-sectional area of ​​the specimen. The elongation at break (%) was calculated by the percentage of the elongation at break to the initial gauge length.

[0081] Barb peel force test:

[0082] 50 mm of antibacterial sutures with blunted barbs prepared in Examples 1-3 and Comparative Examples 1-3 were used as samples. The barbed segments were evenly implanted into pigskin at a preset angle of 30° to a depth of 3 mm. Using a universal testing machine (such as Instron 5967), one end of the suture was fixed with a clamp, and the other end was stretched vertically upward at a constant speed of 5 mm / min until the barbs were completely detached from the tissue. The maximum load (unit: N) during the peeling process was recorded, which is the barb peeling force. Each group of samples was tested at least 5 times, and the average value was taken.

[0083] Biocompatibility test: Referring to GB / T 16886.4-2022, the hemolysis rate of the antibacterial sutures with blunted barbs prepared in Examples 1-3 and the antibacterial sutures with blunted barbs prepared in Comparative Examples 1-3 after contact with rabbit blood was determined.

[0084] Degradation performance test: The antibacterial sutures with passivated barbs prepared in Examples 1-3 and the antibacterial sutures with passivated barbs prepared in Comparative Examples 1-3 were respectively immersed in phosphate buffered saline (PBS) at pH 7.4 and placed in a constant temperature shaking incubator at 37°C. After 28 days, samples were taken to determine the mass loss rate.

[0085] Table 1: Test results of antibacterial sutures with blunted barbs

[0086]

[0087] According to the data in Table 1, the antibacterial sutures with blunted barbs prepared in Examples 1-3 all showed comprehensive advantages in antibacterial properties, mechanical properties, barb stability, biocompatibility and degradation properties.

[0088] Comparing Comparative Example 1 with Example 1, it is evident that the suture produced by single-layer electrospinning using only the shell spinning solution exhibits significant deterioration in all performance aspects. The highest antibacterial rate is only 81.2%, the tensile strength drops to 45.3 MPa, and the barb peel force is only 0.8 N. This difference validates the innovative value of the core layer component. Polycaprolactone in the core layer enhances the material's flexibility and barb bonding strength, while polyhexamethylene biguanide forms a dual antibacterial mechanism with the coating. The absence of the core layer not only significantly reduces antibacterial efficacy but also results in insufficient mechanical support, leading to easy barb detachment and decreased tensile properties. This demonstrates that the core-shell structure design is crucial for achieving comprehensive performance optimization.

[0089] Comparing Comparative Example 2 with Example 1, it can be seen that the suture produced by single-layer electrospinning using only the core layer spinning solution has better performance than Comparative Example 1, but still not as good as Example 1. The highest antibacterial rate is 90.5%, the breaking elongation is 30.2%, and the 28-day mass loss rate is 16.9%. The core reason is the lack of a protective and synergistic effect of the shell layer. The antibacterial components in the single-layer core structure are easily and rapidly lost, and the lack of a dense protective polylactic acid-glycolic acid copolymer shell on the surface leads to an imbalance in degradation rate and insufficient mechanical stability. This demonstrates the creativity of the shell layer design, which not only locks in the antibacterial components of the core layer for long-term release, but also optimizes the surface properties of the suture, improving structural integrity and biocompatibility.

[0090] Comparing Comparative Example 3 with Example 1, it can be seen that omitting the femtosecond laser micro-etching step reduces the puncture-related properties and antibacterial stability of the suture. The barb peeling force is 1.4N, and the antibacterial rate is the highest at 97.6%, which is better than the previous two comparative examples but still lower than Example 1. The local thinning treatment of the barb area by femtosecond laser micro-etching is a key innovative process. This treatment can reduce tissue resistance during puncture. Without this step, the excessive thickness of the barb area leads to increased puncture damage.

[0091] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing an antibacterial suture with blunted barbs, characterized in that, Includes the following steps: Step S1: Add polylactic acid-glycolic acid copolymer, polycaprolactone and polyhexamethylene biguanide to dichloromethane-dimethylformamide mixed solvent, stir to dissolve, and obtain core layer spinning solution; Step S2: Add the polylactic acid-glycolic acid copolymer to the dichloromethane-dimethylformamide mixed solvent, stir to dissolve, and obtain the shell spinning solution; Step S3: The core spinning solution and the shell spinning solution are spun using a coaxial electrospinning process to obtain core-shell structured monofilaments; Step S4: Use femtosecond laser precision machining to form a blunt barb with a preset radius of curvature and tilt angle. Then, use femtosecond laser micro-etching process to locally thin the barb area to obtain a core-shell antibacterial monofilament intermediate with a thinned shell and blunt barbs. Step S5: Immerse the core-shell antibacterial monofilament intermediate with thinned shell and passivated barbs into the antibacterial coating liquid, apply it using the dip-lift method, and then vacuum dry it to obtain the pre-finished core-shell suture with passivated barbs. Step S6: Place the pre-finished core-shell suture with passivated barbs in an ethylene oxide sterilizer for sterilization, and heat set it after sterilization to obtain an antibacterial suture with passivated barbs; The method for preparing the antibacterial coating liquid includes the following steps: Chitosan was dissolved in an aqueous acetic acid solution and stirred until completely dissolved to obtain a chitosan solution. Polyhexamethylene biguanide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were added and stirred until uniform. N-hydroxysuccinimide was added and stirred at room temperature for 2-3 hours. After standing to remove bubbles, an antibacterial coating solution was obtained.

2. The method for preparing an antibacterial suture with blunted barbs according to claim 1, characterized in that, The weight parts of each raw material in the antibacterial coating liquid are as follows: 10-30 parts chitosan, 70-90 parts aqueous acetic acid solution, 2-8 parts polyhexamethylene biguanide, 1-5 parts 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, and 0.5-3 parts N-hydroxysuccinimide; the mass fraction of acetic acid in the aqueous acetic acid solution is 1%-2%.

3. The method for preparing an antibacterial suture with blunted barbs according to claim 1, characterized in that, The weight proportions of each raw material in the core spinning solution in step S1 are as follows: 50-70 parts of polylactic acid-hydroxyacetic acid copolymer, 30-50 parts of polycaprolactone, 0.5-2 parts of polyhexamethylene biguanide, and 200-300 parts of dichloromethane-dimethylformamide mixed solvent.

4. The method for preparing an antibacterial suture with blunted barbs according to claim 1, characterized in that, The weight proportions of each raw material in the shell spinning solution in step S2 are: 40-60 parts of polylactic acid-glycolic acid copolymer and 150-250 parts of dichloromethane-dimethylformamide mixed solvent.

5. The method for preparing an antibacterial suture with blunted barbs according to claim 1, characterized in that, In step S3, the mass ratio of the core spinning solution to the shell spinning solution is 1:1.2-1.

5.

6. The method for preparing an antibacterial suture with blunted barbs according to claim 1, characterized in that, The parameters for the coaxial electrospinning process in step S3 are: spinning voltage 15kV-20kV, receiving distance 18cm-22cm, and feed speed 0.5mL / h-1.5mL / h; the diameter of the core-shell structure monofilament is 0.1mm-0.2mm.

7. The method for preparing an antibacterial suture with blunted barbs according to claim 1, characterized in that, The parameters for femtosecond laser precision machining in step S4 are: wavelength 1030nm-1080nm, pulse width 80fs-120fs, power 40mW-60mW; the radius of curvature of the passivated barbs is 0.05mm-0.1mm, and the tilt angle is 30°-45°. The parameters of the femtosecond laser micro-etching process in step S4 are: power 25mW-35mW, scanning speed 400μm / s-600μm / s, and the thickness of the barbed area is reduced to 15%-25% of the original thickness.

8. The method for preparing an antibacterial suture with blunted barbs according to claim 1, characterized in that, The process parameters for the immersion-lifting method in step S5 are: lifting speed 4mm / s-6mm / s, immersion time 10s-20s; and vacuum drying conditions are: temperature 55℃-65℃, vacuum degree 0.08MPa-0.1MPa, and drying time 10h-14h.

9. The method for preparing an antibacterial suture with blunted barbs according to claim 1, characterized in that, The conditions for ethylene oxide sterilization in step S6 are: temperature 50℃-60℃, humidity 55%-65%, sterilization time 3h-5h; the conditions for heat setting are: temperature 35℃-45℃, tension 0.4N-0.6N, setting time 1h-2h.

Images