High-strength anti-fatigue non-absorbent suture and preparation method thereof

Abstract

The invention relates to the technical field of medical materials, and particularly discloses a high-strength anti-fatigue non-absorbent suture which comprises an inner core with the diameter being 200-300 microns, a transition layer with the thickness being 30-80 microns and a surface functional layer with the thickness being 10-20 microns. The inner core is made of polyarylester and polycaprolactone; the transition layer is a mixture of a polyvinyl alcohol-polyethylene glycol copolymer, amino-terminated polydimethylsiloxane and hydroxypropyl trimethyl ammonium chloride chitosan; the surface functional layer is prepared from sulfonated chitosan and a functional additive; furthermore, in the transition layer, the weight ratio of the polyvinyl alcohol-polyethylene glycol copolymer to the amino-terminated polydimethylsiloxane to the hydroxypropyl trimethyl ammonium chloride chitosan is 10: (1-4): (3-6). The high-strength anti-fatigue non-absorbent suture has the advantages of being high in strength, good in anti-fatigue performance, good in histocompatibility and the like, and can meet the long-term use requirement of a complex clinical repair scene.

Description

Technical Field

[0001] This application relates to the field of medical materials technology, specifically to a high-strength, fatigue-resistant, non-absorbable suture and its preparation method. Background Technology

[0002] Non-absorbable sutures are a core material of surgical sutures used for deep tissue repair and capable of maintaining mechanical properties over a long period.

[0003] Currently, the mainstream non-absorbable sutures used in clinical practice include polypropylene, polyester, polytetrafluoroethylene (PTFE), and ultra-high molecular weight polyethylene (UHMWPE) sutures. Among these, traditional materials such as polypropylene and polyester are relatively inexpensive and, while possessing a certain strength, are prone to stress relaxation under long-term dynamic loads such as activity and exercise. Their strength decreases significantly 6-12 months post-surgery, leading to suture site dehiscence. While PTFE sutures exhibit good fatigue resistance, their loose molecular structure results in insufficient nodular strength, making them unsuitable for high-intensity repair scenarios. UHMWPE sutures have become a research hotspot due to their high modulus; however, they suffer from drawbacks such as strong surface inertness, low cell adhesion, susceptibility to foreign body reactions, and poor biocompatibility with human tissues. These limitations prevent them from meeting the requirements for long-term clinical implantation, significantly restricting their application in chronic wounds and other scenarios requiring high tissue integration.

[0004] Therefore, there is an urgent need to develop a non-absorbable suture with high strength, good fatigue resistance, and good tissue compatibility to meet the long-term use requirements of complex clinical repair scenarios. Summary of the Invention

[0005] To address the problems of insufficient strength, poor fatigue resistance, and poor tissue compatibility of existing medical non-absorbable sutures, this application provides a high-strength, fatigue-resistant non-absorbable suture and its preparation method.

[0006] In a first aspect, this application provides a high-strength, fatigue-resistant, non-absorbable suture, employing the following technical solution: A high-strength, fatigue-resistant, non-absorbable suture includes an inner core with a diameter of 200-300 μm, a transition layer with a thickness of 30-80 μm, and a surface functional layer with a thickness of 10-20 μm. The inner core is composed of polyarylate and polycaprolactone; the transition layer is a mixture of polyvinyl alcohol-polyethylene glycol copolymer, amino-terminated polydimethylsiloxane, and hydroxypropyltrimethylammonium chloride chitosan; and the surface functional layer is composed of sulfonated chitosan and functional additives.

[0007] This application provides a three-layer composite non-absorbable suture with excellent mechanical properties, fatigue resistance, and biocompatibility. It overcomes the shortcomings of existing non-absorbable sutures and meets the long-term use requirements of complex clinical repair scenarios. Specifically, the inner core is a blend of polyarylate and polycaprolactone. Polyarylate possesses high modulus and excellent mechanical load-bearing capacity, providing core strength support for the suture, while polycaprolactone has good flexibility, compensating for the brittleness of polyarylate. Together, they ensure load transfer efficiency, improve deformation resistance, and enhance the overall strength of the suture. The transition layer is a composite of polyvinyl alcohol-polyethylene glycol copolymer, amino-terminated polydimethylsiloxane, and hydroxypropyltrimethylammonium chloride chitosan. The viscoelasticity of the polyvinyl alcohol-polyethylene glycol copolymer effectively absorbs the energy of active and dynamic loads; the flexible segments of the amino-terminated polydimethylsiloxane further enhance the fatigue resistance of the suture; and the hydroxypropyltrimethylammonium chloride chitosan, through its cationic groups, forms multiple interactions with the core and surface layers, strengthening interlayer bonding and thus improving fatigue resistance. This transition layer design provides an energy buffer, significantly improving the mechanical strength and fatigue resistance of the suture. Sulfonated chitosan is used as the base for the surface functional layer; its sulfonic acid groups promote extracellular matrix deposition, and the introduction of functional additives can improve cell adhesion and tissue integration speed, while also endowing the suture with additional functions such as antibacterial and anti-inflammatory properties. In summary, the high-strength, fatigue-resistant, non-absorbable suture provided in this application can solve the problems of insufficient strength, poor fatigue resistance, and poor tissue compatibility of existing sutures. It is fully applicable to clinical scenarios that require long-term dynamic support, such as deep tissue repair and chronic wound closure, and has excellent reliability and biocompatibility.

[0008] Optionally, in the transition layer, the weight ratio of polyvinyl alcohol-polyethylene glycol copolymer, amino-terminated polydimethylsiloxane, and hydroxypropyltrimethylammonium chloride chitosan is 10:(1-4):(3-6).

[0009] Optionally, in the transition layer, the weight ratio of polyvinyl alcohol-polyethylene glycol copolymer, amino-terminated polydimethylsiloxane, and hydroxypropyltrimethylammonium chloride chitosan is 10:3:5.

[0010] Optionally, the weight ratio of the polyarylate to the polycaprolactone is 2:(0.8-1.5).

[0011] Optionally, the polyarylate is Vectran® fiber with a tensile modulus ≥100 GPa; the sulfonated chitosan has a degree of deacetylation ≥92% and a degree of sulfonation 35-45%.

[0012] Optionally, the functional additive is selected from one or more of recombinant human epidermal growth factor, β-tricalcium phosphate, polylysine, and hyaluronic acid.

[0013] Secondly, this application provides a method for preparing a high-strength, fatigue-resistant, non-absorbable suture, comprising the following steps: The inner core material is melted and pre-oriented yarn is obtained by electrospinning, which is then twisted and kneaded to form fiber stitching. A transition layer solution is applied to the outer surface of the inner core using an immersion method, followed by vacuum drying. The surface functional layer mixed solution reacts with the transition layer through a vapor phase grafting process; Finally, through heat stretching and shaping, a high-strength, fatigue-resistant, non-absorbable suture is obtained.

[0014] In summary, this application has the following beneficial effects: This application uses a mixture of polyarylate and polycaprolactone as the core, a mixture of polyvinyl alcohol-polyethylene glycol copolymer, amino-terminated polydimethylsiloxane and hydroxypropyltrimethylammonium chloride chitosan as the transition layer, and sulfonated chitosan and functional additives are coated on the surface to obtain a non-absorbable suture with a tensile breaking strength of 4.8-5.5 N / tex and a tensile breaking strength retention rate of 85.3-92.3% after 5000 cycles of loading. Its excellent tensile breaking strength and fatigue resistance can fully meet the long-term use requirements of complex clinical repair scenarios. Detailed Implementation

[0015] This application provides a high-strength, fatigue-resistant, non-absorbable suture, comprising an inner core with a diameter of 200-300 μm, a transition layer with a thickness of 30-80 μm, and a surface functional layer with a thickness of 10-20 μm; The inner core is composed of polyarylate and polycaprolactone; further, in the transition layer, the weight ratio of polyvinyl alcohol-polyethylene glycol copolymer, amino-terminated polydimethylsiloxane and hydroxypropyltrimethylammonium chloride chitosan is 10:(1-4):(3-6).

[0016] The transition layer is a mixture of polyvinyl alcohol-polyethylene glycol copolymer, amino-terminated polydimethylsiloxane, and hydroxypropyltrimethylammonium chloride chitosan; further, in the transition layer, the weight ratio of polyvinyl alcohol-polyethylene glycol copolymer, amino-terminated polydimethylsiloxane, and hydroxypropyltrimethylammonium chloride chitosan is 10:(1-4):(3-6).

[0017] The surface functional layer comprises sulfonated chitosan and functional additives. The functional additives are selected from one or more of recombinant human epidermal growth factor, β-tricalcium phosphate, polylysine, and hyaluronic acid.

[0018] This application also provides a method for preparing high-strength, fatigue-resistant, non-absorbable sutures, including the following steps: (1) Polyarylate and polycaprolactone are melted and obtained by electrospinning to form a pre-oriented core yarn, which is then twisted and kneaded to form a fiber suture with a diameter of 200-300μm; (2) Prepare a transition layer solution, then soak the fiber suture in the transition layer solution to coat the inner core with a layer of transition layer solution, and then dry it under vacuum. The surface is coated with a suture with a transition layer thickness of 30-80μm.

[0019] (3) Prepare a surface functional layer mixed solution, and then react the surface functional layer mixed solution with the transition layer through a gas phase grafting process, so that the amino groups on the surface of the transition layer and the sulfonic acid groups of sulfonated chitosan covalently bond, forming a surface functional layer on the surface of the transition layer. (4) Finally, after heat stretching and shaping, a high-strength, fatigue-resistant, non-absorbable suture is obtained.

[0020] In the embodiments of this application, the polyarylate is Vectran® fiber with a tensile modulus of 120 GPa; the polycaprolactone has a molecular weight of 4000 kDa and was purchased from Jiangsu Runfeng Synthetic Technology Co., Ltd.; the polyvinyl alcohol-polyethylene glycol copolymer has CAS number 96734-39-3 and was purchased from Merck; the amino-terminated polydimethylsiloxane (PDMS-NH2) has a weight-average molecular weight of 6000 kDa and an amino content of 1.0 mmol / g and was purchased from Xi'an Qiyue Biotechnology Co., Ltd.; the degree of substitution of hydroxypropyltrimethylammonium chloride chitosan is 90% and was purchased from Hubei Watson Chemical Technology Co., Ltd.; the degree of deacetylation of sulfonated chitosan is 95% and the degree of sulfonation is 40%; the raw materials, reagents, solvents, etc. used in this application are all commercially available.

[0021] The present application will be further described in detail below with reference to embodiments and performance testing. Examples 1-7

[0022] Examples 1-7 each provide a high-strength, fatigue-resistant, non-absorbable suture.

[0023] The difference in the above embodiments is that the weight ratio of each substance in the transition layer is as shown in Table 1 below.

[0024] The method for preparing high-strength, fatigue-resistant, non-absorbable sutures provided in Examples 1-7 includes the following steps: (1) Polyarylate and polycaprolactone are mixed at a weight ratio of 2:0.8 and placed in a twin-screw extruder for melt blending; then the melt after melt blending is introduced into the spinneret module of the electrospinning device, the spinneret diameter is set to 0.3 mm, the spinning temperature is set to 300 °C, a high voltage electrostatic field voltage of 30 kV is applied, the distance between the receiving roller and the spinneret is 18 cm, and the receiving roller speed is 1000 r / min; the melt is stretched into ultrafine fibers under the action of the electrostatic field, and after being pulled by the high-speed receiving roller, pre-oriented polyarylate-polycaprolactone composite fibers are obtained, and the fiber diameter is controlled to be 10 μm; the above composite fibers are spun together, and then twisted on a twisting machine and rubbed in a rubbing machine to make the fibers tightly entangled, and finally a core fiber suture with a diameter of 0.2 mm is obtained.

[0025] (2) Mix the transition layer material according to the weight ratio described in Table 1 and add it to a 70wt% ethanol aqueous solution with a solid-liquid ratio of 1:5. Stir at 65°C for 3 hours to completely dissolve it and obtain a transition layer solution. Immerse the inner core suture in the transition layer solution, then take it out and vacuum dry it at 60°C and -0.1MPa to obtain a suture with a surface-coated transition layer thickness of 50μm.

[0026] (3) Sulfonated chitosan and β-tricalcium phosphate were mixed at a weight ratio of 9:1 and added to a 5wt% aqueous acetic acid solution with a solid-liquid ratio of 1:20. The mixture was stirred at 50℃ for 1 h and then ultrasonically dispersed for 30 min to obtain a surface functional layer mixed solution. The suture coated with the transition layer was fixed in a gas-phase grafting reactor and vacuumed to -0.1 MPa. The surface functional layer mixed solution was then atomized into droplets with a particle size of 1-5 μm by an ultrasonic atomizing device. The atomized droplets were introduced into the reactor with a carrier gas (nitrogen, flow rate 100 mL / min). The reaction temperature was set at 80℃ and the reaction time was 3 h to covalently bond the amino groups on the surface of the transition layer with the sulfonic acid groups of sulfonated chitosan to form a surface functional layer with a thickness of 20 μm. After the reaction was completed, the mixture was rinsed with deionized water.

[0027] (4) The suture after grafting the functional layer is placed in a hot stretching device and hot stretching is performed at a temperature of 80℃ and a stretching ratio of 1.3 times, and the stretching state is maintained for 15 min; then the stretched suture is placed in an oven and set at 70℃ for 30 min to obtain a high-strength fatigue-resistant non-absorbent suture.

[0028] Table 1. Weight ratio of each substance in the transition layer of Examples 1-7 Examples 8-10

[0029] Examples 8-10 each provide a high-strength, fatigue-resistant, non-absorbable suture.

[0030] The difference between the above embodiments and Embodiment 3 is that the weight ratio of polyarylate and polycaprolactone in the inner core is as shown in Table 2 below.

[0031] Table 2. Weight ratio of polyarylate and polycaprolactone in the core of Examples 8-10 Comparative Example 1

[0032] Comparative Example 1 provides a high-strength, fatigue-resistant, non-absorbable suture.

[0033] The difference between the above comparative example and Example 3 is that the transition layer uses a mixture of polyvinyl alcohol-polyethylene glycol copolymer and amino-terminated polydimethylsiloxane in a weight ratio of 10:8. Comparative Example 2

[0034] Comparative Example 2 provides a high-strength, fatigue-resistant, non-absorbable suture.

[0035] The difference between the above comparative example and Example 3 is that the transition layer uses a mixture of polyvinyl alcohol-polyethylene glycol copolymer and hydroxypropyltrimethylammonium chloride chitosan in a weight ratio of 10:8. Comparative Example 3

[0036] Comparative Example 3 provides a high-strength, fatigue-resistant, non-absorbable suture.

[0037] The difference between the above comparative example and Example 3 is that the inner core is polyarylate. Performance testing

[0038] The high-strength, fatigue-resistant, non-absorbable sutures obtained in Examples 1-10 and Comparative Examples 1-3 were subjected to various performance tests, and the results are shown in Table 3 below.

[0039] Table 3 Performance test results of non-absorbable sutures obtained in Examples 1-10 and Comparative Examples 1-3

[0040] According to the test results in Table 3, the tensile breaking strength of the high-strength, fatigue-resistant, non-absorbable sutures obtained in Examples 1-10 is 4.8-5.5 N / tex, and the tensile breaking strength retention rate after 5000 cycles is 85.3-92.3%. Comparative Examples 1-2 used a mixture of polyvinyl alcohol-polyethylene glycol copolymer and amino-terminated polydimethylsiloxane at a weight ratio of 10:8, or a mixture of polyvinyl alcohol-polyethylene glycol copolymer and hydroxypropyltrimethylammonium chloride chitosan at a weight ratio of 10:8, as a transition layer. The tensile breaking strength retention rate of the obtained non-absorbable sutures after 5000 cycles was only 66.5-71.9%. Comparative Example 3 used polyarylate as the inner core, and the tensile breaking strength of the obtained non-absorbable suture was only 3.7 N / tex. Therefore, this application uses a mixture of polyarylate and polycaprolactone as the core, a mixture of polyvinyl alcohol-polyethylene glycol copolymer, amino-terminated polydimethylsiloxane and hydroxypropyltrimethylammonium chloride chitosan as the transition layer, and sulfonated chitosan and functional additives are coated on the surface. The resulting non-absorbable suture has excellent tensile strength and fatigue resistance, and can meet the long-term use requirements of complex clinical repair scenarios.

[0041] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A high-strength, fatigue-resistant, nonabsorbable suture, characterized in that, It includes an inner core with a diameter of 200-300μm, a transition layer with a thickness of 30-80μm, and a surface functional layer with a thickness of 10-20μm; The inner core is composed of polyarylate and polycaprolactone; the transition layer is a mixture of polyvinyl alcohol-polyethylene glycol copolymer, amino-terminated polydimethylsiloxane, and hydroxypropyltrimethylammonium chloride chitosan; and the surface functional layer is composed of sulfonated chitosan and functional additives.

2. The high-strength, fatigue-resistant, non-absorbable suture according to claim 1, characterized in that, In the transition layer, the weight ratio of polyvinyl alcohol-polyethylene glycol copolymer, amino-terminated polydimethylsiloxane, and hydroxypropyltrimethylammonium chloride chitosan is 10:(1-4):(3-6).

3. The high-strength, fatigue-resistant, non-absorbable suture according to claim 1, characterized in that, In the transition layer, the weight ratio of polyvinyl alcohol-polyethylene glycol copolymer, amino-terminated polydimethylsiloxane, and hydroxypropyltrimethylammonium chloride chitosan is 10:3:

5.

4. The high-strength, fatigue-resistant, non-absorbable suture according to claim 1, characterized in that, The weight ratio of the polyarylate to the polycaprolactone is 2:(0.8-1.5).

5. The high-strength, fatigue-resistant, non-absorbable suture according to claim 1, characterized in that, The polyarylate is Vectran® fiber with a tensile modulus ≥100 GPa; the sulfonated chitosan has a deacetylation degree ≥92% and a sulfonation degree of 35-45%.

6. The high-strength, fatigue-resistant, non-absorbable suture according to claim 1, characterized in that, The functional additive is selected from one or more of recombinant human epidermal growth factor, β-tricalcium phosphate, polylysine, and hyaluronic acid.

7. The method for preparing high-strength, fatigue-resistant, non-absorbable sutures as described in any one of claims 1-6, characterized in that, Includes the following steps: The core material is melted and pre-oriented yarn is obtained by electrospinning, which is then twisted and kneaded to form fiber stitches. A transition layer solution was applied to the outside of the core layer using an immersion method, followed by vacuum drying. The surface functional layer mixed solution reacts with the transition layer through a vapor phase grafting process; Finally, through heat stretching and shaping, a high-strength, fatigue-resistant, non-absorbable suture is obtained.

Images