High-strength and anticoagulant suture line and preparation method thereof

Abstract

The invention discloses a high-strength and anticoagulant suture line which is formed by heating heparin modified polycaprolactone serving as a raw material and then pulling the heparin modified polycaprolactone, wherein the heparin modified polycaprolactone is obtained by taking heparin / coupling agent / buffer solution and polycaprolactone solution as main raw materials and carrying out grafting reaction. According to the suture line, the problems that an existing fine suture line is poor in mechanical strength and anticoagulation capacity and the like can be effectively solved; the related raw materials are wide in obtaining approach, and the preparation method is simple, convenient and feasible, low in cost and suitable for popularization and application.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical materials, and particularly relates to a high-strength, anticoagulant suture and a preparation method thereof. Background Art

[0002] Sutures are key materials in modern surgical operations, used for suturing wounds, closing tissues or organs. With the progress of medical technology, the types and properties of sutures have been continuously improved to meet different surgical needs. The materials of traditional sutures (such as nylon, polylactic acid, etc.) can cause thrombus formation at the wound site, which in turn leads to complications, such as blood flow restriction, increased inflammation, and serious cardiovascular diseases, etc. By integrating anticoagulant properties into the design of sutures, the coagulation risk can be effectively reduced, the healing process can be promoted smoothly, the possibility of complications can be reduced, and the overall success rate of surgical intervention can be improved.

[0003] Microsurgery has very high requirements for sutures. It not only requires fine dimensions (diameter < 0.05 mm), but also excellent mechanical properties, and at the same time, it needs to have anti-thrombosis properties. However, the fine sutures currently available on the market still tend to break easily. Therefore, further developing new high-strength and anticoagulant surgical sutures is a practical and significant research direction. Summary of the Invention

[0004] The main purpose of the present invention is to provide a new type of high-strength, anticoagulant suture material aiming at the problems and deficiencies existing in the prior art, and to improve the problems such as poor mechanical strength and anticoagulant ability of existing fine sutures.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A high-strength, anticoagulant suture, which is made by heating and stretching a heparin-modified polycaprolactone as a raw material; wherein, the heparin-modified polycaprolactone is obtained by grafting reaction using heparin / coupling agent / buffer solution and polycaprolactone solution as main raw materials.

[0007] Furthermore, the coupling agent includes N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride.

[0008] In the above solution, during the preparation process of the heparin-modified polycaprolactone, the mass ratio of the introduced heparin, coupling agent, and polycaprolactone is 1:0.2 - 0.5:1.0 - 2.0.

[0009] In the above solution, the temperature used for the grafting reaction is 65 - 80 °C, and the reaction time is 48 - 96 h.

[0010] Further, the grafting reaction is carried out under stirring conditions, and the stirring speed is 300 - 500 rpm.

[0011] Further, the diameter of the suture is 0.025 - 0.05 mm.

[0012] In the above solution, the heating temperature is 75 - 85 °C.

[0013] In the above solution, the molecular weight of the polycaprolactone is 10,000 - 80,000; the molecular weight of heparin is 8,000 - 15,000.

[0014] In the above solution, in the heparin / coupling agent / buffer solution, the pH value of the buffer solution used is 5 - 7.5.

[0015] Further, the buffer solution can be selected from 2 - morpholinoethanesulfonic acid buffer solution, etc.

[0016] In the above solution, the solvent used in the polycaprolactone solution is one or more of tetrahydrofuran, hexafluoroisopropanol, etc.

[0017] The preparation method of the above - mentioned high - strength and anticoagulant suture includes the following steps:

[0018] 1) Add the polycaprolactone solution to the heparin / coupling agent / buffer solution, and carry out a heating reaction under stirring conditions; after the reaction is completed, use a rotary evaporator to spin - dry and remove the solvent in the reaction system;

[0019] 2) Completely dissolve the product obtained in step 1) with hexafluoroisopropanol, and then drop it into water to wash away the unreacted heparin, coupling agent, and buffer; dry the obtained product; obtain the polycaprolactone - heparin - based suture material;

[0020] 3) Carry out a water - bath heating on the obtained heparin - modified polycaprolactone (polycaprolactone - heparin - based suture material), perform traction stretching while it is hot, and after drying and sterilization, obtain the high - strength and anticoagulant suture.

[0021] In the above solution, in the heparin / coupling agent / buffer solution, the buffer solution used is 2 - morpholinoethanesulfonic acid buffer solution, its concentration is 3.0 - 7.0 mg / mL, and the pH value is 5.7 - 6.2.

[0022] In the above solution, in the heparin / coupling agent / buffer solution, the concentration of heparin is 0.04 - 0.1 g / mL, and the concentration of the coupling agent is 0.03 - 0.08 g / mL.

[0023] Furthermore, the concentration of the coupling agent N-hydroxysuccinimide is 0.02 - 0.05 g / mL, and the concentration of the coupling agent 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride is 0.01 - 0.03 g / mL.

[0024] In the above solution, the pH value of the heparin / coupling agent / buffer solution is 5 - 7.5.

[0025] Furthermore, the heparin / coupling agent / buffer solution is obtained by dissolving heparin and the coupling agent in the buffer solution, adjusting the pH value (5 - 7.5), and performing activation treatment.

[0026] Furthermore, the time of the activation treatment (under stirring conditions) is 3 - 5 h.

[0027] In the above solution, the concentration of the polycaprolactone solution is 0.12 - 0.225 g / mL.

[0028] In the above solution, the volume ratio of the heparin / coupling agent / buffer solution to the polycaprolactone solution is 1:(1.5 - 3.0).

[0029] In the above solution, the washing process needs to be washed 3 - 5 times.

[0030] In the above solution, the drying process includes drying in a constant temperature oven at a temperature of 50 - 60 °C for 5 - 10 h or drying in a vacuum oven for 24 - 36 h.

[0031] In the above solution, the traction and stretching step adopts a stepwise temperature-controlled pulling process. The specific steps include: under the water bath condition of 75 - 85 °C, one end of the softened heparin-modified polycaprolactone is pulled out at a speed of 0.5 - 1.0 cm / s (using tools such as a glass rod) to obtain a thick line segment with a diameter of 0.75 - 1.5 mm; then the obtained thick line segment is placed in an environment of 0 - 30 °C and continuously stretched at a speed of 0.5 - 1.0 mm / s to obtain a suture with a diameter of 0.025 - 0.05 mm.

[0032] In the above solution, the disinfection means irradiating overnight under an ultraviolet lamp.

[0033] The surgical suture prepared according to the above solution has a diameter of 15 - 150 μm; its ultimate tensile strength can reach 750 - 850 MPa, and the heparin concentration on the surface reaches 5.0 - 8.0 μg / cm 2 , the activated partial thromboplastin time is 290 - 310 s, and the hemolysis rate is as low as 0.15 - 0.25%.

[0034] Compared with the prior art, the beneficial effects of the present invention include:

[0035] 1) The main component of the suture in the present invention is heparin-modified polycaprolactone, which is obtained by using heparin and polycaprolactone as the main raw materials and carrying out grafting reaction in combination with a composite coupling agent and a buffer solution. The heparin-modified polycaprolactone has excellent biodegradability, biocompatibility and anticoagulant properties.

[0036] 2) The present invention uses a pulling method to prepare fine sutures. The step-by-step pulling process based on different temperatures and pulling rates is beneficial to the recrystallization of the material, increasing the degree of material crystallization by 10-20% during the stretching process, effectively overcoming the deficiencies in mechanical strength and other aspects of the sutures obtained by traditional preparation methods, and further promoting the improvement of anticoagulant properties; it can achieve a smaller diameter on the premise of ensuring mechanical strength, which is beneficial to opening up new application spaces for the minimally invasive suture field.

[0037] 3) The preparation method of the high-strength and anticoagulant fine suture is simple and easy to implement, with simple operation, wide access to raw materials, low production cost, and has broad application value and promotion potential. Description of the Drawings

[0038] Figure 1 is the FTIR test chart of the materials obtained in Example 1 and Comparative Examples 1-2 of the present invention;

[0039] Figure 2 is the fitting equation of the surface heparin concentration of the materials obtained in Example 1 and Comparative Example 1 of the present invention;

[0040] Figure 3 is the electron microscope characterization result chart of the material obtained in Example 1 of the present invention;

[0041] Figure 4 is the one-dimensional wide-angle X-ray diffraction characterization chart of the material obtained in Example 1 of the present invention before and after stretching;

[0042] Figure 5 is the hemolysis rate test result of the materials obtained in Example 1 and Comparative Examples 1-2 of the present invention;

[0043] Figure 6 is the photo of the healing situation of the material obtained in Example 1 of the present invention acting on the suture of the abdominal aorta of a mouse. Detailed Embodiments

[0044] The technical solutions adopted in the present invention are described in detail below through specific implementation examples. What is described is only a part of the present invention and does not represent all embodiments. Unless otherwise specified, the experimental methods adopted in the present invention are all conventional methods, and the instrument equipment adopted are all commercial products in the technical field.

[0045] In the following examples and comparative examples, the polycaprolactone used was of analytical grade, provided by Shanghai Macklin Biochemical Co., Ltd., with a molecular weight of 50,000 - 80,000; heparin was of analytical grade, provided by Energy Chemical Co., Ltd., with a molecular weight of 8,000 - 10,000.

[0046] The tetrahydrofuran used was of analytical grade, provided by Energy Chemical Co., Ltd.; hexafluoroisopropanol was of analytical grade, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.; 2-morpholinoethanesulfonic acid was of biotech grade, provided by Shanghai Macklin Biochemical Co., Ltd.; N-hydroxysuccinimide was of analytical grade, provided by Energy Chemical Co., Ltd.; 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride was of analytical grade, provided by Energy Chemical Co., Ltd.; sodium hydroxide was of chemical pure grade, provided by Tianjin Fuchen Chemical Reagent Co., Ltd.

[0047] Example 1

[0048] A high-strength and anticoagulant fine surgical suture, the preparation method of which comprises the following steps:

[0049] 1) Weigh 1.17 g of 2-morpholinoethanesulfonic acid, dissolve it in 200 mL of deionized water, and adjust the pH value of the solution to 6.2 with a sodium hydroxide solution (concentration: 0.125 g / mL) to obtain a 2-morpholinoethanesulfonic acid buffer solution;

[0050] Weigh 1.5 g of heparin, 0.45 g of N-hydroxysuccinimide and 0.3 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, dissolve them in 20 mL of the obtained 2-morpholinoethanesulfonic acid buffer solution, and add 0.05 g of sodium hydroxide (adjust the pH value of the obtained heparin / coupling agent / buffer solution to 7.2), stir for 3 - 5 h to obtain a heparin / coupling agent / buffer solution;

[0051] Add 1.8 g of polycaprolactone to 8 mL of tetrahydrofuran, heat to 50 °C, stir to dissolve to obtain a polycaprolactone / tetrahydrofuran solution;

[0052] 2) Mix the heparin / coupling agent / buffer solution obtained in step 1) and the polycaprolactone / tetrahydrofuran solution, react under magnetic stirring (stirring speed: 400 rpm) and at 80 °C for 48 h; use a rotary evaporation device to remove the solvent in the reaction system;

[0053] 3) Dissolve 3.0 g of the product obtained in step 2) in 12 mL of hexafluoroisopropanol, then drop the obtained mixture into 500 mL of deionized water, filter under reduced pressure (4000 Pa), repeat 3 times, and completely dry and wash to obtain a polycaprolactone-heparin-based suture material;

[0054] 4) Heat the obtained polycaprolactone-heparin-based suture material in a water bath (temperature: 75 °C). After the water bath temperature stabilizes, use a glass rod to pull out one end of the softened polycaprolactone-heparin-based suture material to obtain a thick line segment with a diameter of 0.75 - 1.5 mm. Place the obtained thick line segment in a room temperature environment of 20 - 30 °C and continue to stretch it at a speed of 0.5 - 1.0 mm / s to obtain a surgical suture with a diameter of 0.025 - 0.05 mm.

[0055] Example 2

[0056] A high-strength, anticoagulant surgical suture, and its preparation method includes the following steps:

[0057] 1) Weigh 1.17 g of 2-morpholinoethanesulfonic acid, dissolve it in 200 mL of deionized water, and adjust the pH value of the solution to 6.2 with a sodium hydroxide solution (concentration: 0.125 g / mL) to obtain a 2-morpholinoethanesulfonic acid buffer solution.

[0058] Weigh 1.5 g of heparin, 0.45 g of N-hydroxysuccinimide, and 0.3 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, dissolve them in 20 mL of the obtained 2-morpholinoethanesulfonic acid buffer solution, and add 0.05 g of sodium hydroxide (adjust the pH value of the obtained heparin / coupling agent / buffer solution to 7.2), stir for 3 - 5 h to obtain a heparin / coupling agent / buffer solution.

[0059] Add 1.8 g of polycaprolactone to 8 mL of tetrahydrofuran, heat to 50 °C, and stir to dissolve to obtain a polycaprolactone / tetrahydrofuran solution.

[0060] 2) Mix the heparin / coupling agent / buffer solution and the polycaprolactone / tetrahydrofuran solution obtained in step 1), react under magnetic stirring (stirring speed: 400 rpm) and at 80 °C for 48 h; use a rotary evaporation device to remove the solvent in the reaction system.

[0061] 3) Dissolve 3.0 g of the product obtained in step 2) in 12 mL of hexafluoroisopropanol, then add the obtained mixture dropwise to 500 mL of deionized water, filter under reduced pressure (4000 Pa), repeat 3 times, and completely dry and wash to obtain a polycaprolactone-heparin-based suture material.

[0062] 4) Heat the obtained polycaprolactone-heparin-based suture material in a water bath (temperature: 75 °C). After the water bath temperature stabilizes, use a glass rod to pull out one end of the softened polycaprolactone-heparin-based suture material to obtain a thick line segment with a diameter of 0.75 - 1.5 mm. Place the obtained thick line segment in a low-temperature environment of 0 - 10 °C and continue to stretch it at a speed of 0.5 - 1.0 mm / s to obtain a surgical suture with a diameter of 0.025 - 0.05 mm.

[0063] Comparative Example 1

[0064] A surgical suture based on the electrospinning process, and its preparation method includes the following steps:

[0065] 1) Weigh 1.17 g of 2-morpholinoethanesulfonic acid, dissolve it in 200 mL of deionized water, and adjust the pH value of the solution to 6.2 with a sodium hydroxide solution (concentration: 0.125 g / mL) to obtain a 2-morpholinoethanesulfonic acid buffer solution;

[0066] Weigh 1.5 g of heparin, 0.45 g of N-hydroxysuccinimide, and 0.3 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, dissolve them in 20 mL of the obtained 2-morpholinoethanesulfonic acid buffer solution, and add 0.05 g of sodium hydroxide (adjust the pH value of the obtained buffer solution to 7.2), stir for 2 h to obtain a heparin / coupling agent / buffer solution;

[0067] Add 1.8 g of polycaprolactone to 8 mL of tetrahydrofuran, heat to 50 °C, and stir to dissolve to obtain a polycaprolactone / tetrahydrofuran solution;

[0068] 2) Mix the heparin / coupling agent / buffer solution and the polycaprolactone / tetrahydrofuran solution obtained in step 1), react under magnetic stirring (stirring speed: 400 rpm) and at 80 °C for 48 h; use a rotary evaporation device to remove the solvent in the reaction system;

[0069] 3) Dissolve 3.0 g of the product obtained in step 2) in 12 mL of hexafluoroisopropanol, then drop the obtained mixture into 500 mL of deionized water, filter under reduced pressure (4000 Pa), repeat 3 times, and completely dry and wash to obtain a polycaprolactone-heparin-based suture material;

[0070] 4) Prepare a polycaprolactone-heparin solution (0.2 g / mL) according to the ratio of 1 g of polycaprolactone-heparin-based suture material dissolved in 5 mL of hexafluoroisopropanol, stir at room temperature until completely dissolved; let it stand to remove bubbles to obtain the electrospinning solution to be spun;

[0071] Use a 1 mL syringe to suck the bubble-free electrospinning solution to be spun, set the electrospinning parameters as: liquid output speed 8 μL / min, distance from the receiver 15 cm, voltage 15 kV, electrospinning time 9 min; obtain polycaprolactone-heparin-based fibers (diameter: 100 - 200 μm); twist the obtained fibers into sutures with a diameter of 70 - 100 μm.

[0072] Comparative Example 2

[0073] A polycaprolactone-based surgical suture, and its preparation method includes the following steps:

[0074] Heat the polycaprolactone solid in a water bath (temperature: 70 °C). After the water bath temperature stabilizes, use a glass rod to pull one end of the softened polycaprolactone solid out of the water surface to obtain a line segment with a relatively thick diameter (0.75 - 1.5 mm). Continuously stretch the obtained line segment with a relatively thick diameter in a low-temperature environment (ice water bath) at a speed of 0.5 - 1.0 mm / s to obtain a suture with a diameter of 100 - 150 μm.

[0075] Comparative Example 3

[0076] An anticoagulant fine surgical suture, whose preparation method is substantially the same as that of Example 1, except that a single pulling process is adopted, and the specific steps are as follows:

[0077] In step 4), heat the polycaprolactone-heparin-based suture material in a water bath (temperature: 75 °C). After the water bath temperature stabilizes, use a glass rod to pull one end of the softened polycaprolactone-heparin-based suture material out, and stretch it in size at a speed of 0.5 - 1.0 mm / s to obtain a surgical suture with a diameter of 0.05 - 0.10 mm.

[0078] Performance test:

[0079] Perform infrared spectroscopy, surface heparin concentration, mechanical strength, anticoagulant performance, hemolysis rate, and animal experiments on the suture materials and sutures obtained in Example 1 and Comparative Examples 1 - 3 respectively. The specific steps include:

[0080] 1) Infrared spectroscopy test

[0081] The wavenumber scanning range of the infrared spectroscopy test is 1000 - 4000 cm -1 , and the specific test results are shown in Figure 1 . It can be seen that compared with pure polycaprolactone, polycaprolactone-heparin shows an obvious absorption peak at 3300 - 3480 cm -1 , which is the vibration peak of N-H, O-H, or C-N; the new absorption peaks at 1645 and 1260 cm -1 can be considered as the characteristic peaks of the amino group (-NH) and sulfonic acid group (-SO 3 ) in heparin, proving that heparin has been successfully bonded to the surface of polycaprolactone.

[0082] 2) Heparin content test

[0083] Prepare 0.0166% heparin solution and 0.005% toluidine blue solution using 0.2% NaCl solution; adjust the pH of the 0.005% toluidine blue solution to 2.0; mix the above solutions, and after complete reaction, extract the heparin-toluidine blue complex with n-hexane; measure the absorbance of the remaining toluidine blue solution in the aqueous phase at 630 nm and plot the standard curve. Make regular-shaped small pieces of polycaprolactone-heparin and repeat the above experimental steps to measure the corresponding absorbance rate.

[0084] The fitting equation of the surface heparin concentration is shown in Figure 2 ; Through calculation, the heparin concentration on the surface of polycaprolactone-heparin is 6.1 μg / cm 2 .

[0085] 3) Microscopic morphology and crystallinity test

[0086] After testing, the diameter of the surgical suture obtained in Example 1 is 25 - 50 μm (see Figure 3 ).

[0087] The suture obtained in Example 1 increases the crystallinity of the material by 10 - 20% during the stretching process (see Figure 4 corresponding diffraction characterization data).

[0088] 4) Mechanical property test

[0089] Use a universal tensile testing machine to test the mechanical properties of the materials of the present invention. Measure the length of the material with a vernier caliper and measure the diameter of the material with a micrometer. Determine the mechanical strength of the present invention on the universal tensile testing machine with an elongation speed of 1 mm / min. The specific test results are shown in Table 1.

[0090] Table 1 Mechanical property test results of the sutures obtained in Example 1 and Comparative Examples 1 - 3

[0091] Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Ultimate tensile strength / MPa 797±34 33±3 756±26 437±45

[0092] The results show that Example 1 has a greater ultimate stress that can be borne compared to Comparative Example 1, Comparative Example 2, and Comparative Example 3, indicating that the present invention has better mechanical properties.

[0093] 5) Anticoagulant property test

[0094] Use activated partial thromboplastin time (APTT) to reflect the anticoagulant ability of polycaprolactone-heparin. Wash the above Example 1, Comparative Example 1, and Comparative Example 2 with deionized water and dry them, and sterilize and store them under ultraviolet light at 4°C; centrifuge the plasma obtained from porcine whole blood and 0.025 mol / L CaCl 2Incubate 0.2 mL of each solution at 37°C, add it to the test tubes containing Example 1, Comparative Example 1, and Comparative Example 2 above, and start timing; when a trace amount of fibrin appears in the test tube, the activated partial thromboplastin time is obtained. The specific test results are shown in Table 2.

[0095] Table 2 Test results of the anticoagulant ability of the sutures obtained in Example 1 and Comparative Examples 1-3

[0096]

[0097] The results show that, compared with Comparative Example 1 and Comparative Example 2, Example 1 has a longer plasma recalcification clotting time, indicating that the present invention meets the performance requirements for anticoagulation.

[0098] 6) Hemolysis test

[0099] Dilute porcine whole blood 6-fold with 0.9% normal saline; add the sutures obtained in Example 1, Comparative Example 1, and Comparative Example 2 above to centrifuge tubes containing diluted porcine whole blood and 0.9% normal saline (1:5) respectively, and incubate in a biochemical incubator at 37°C for 1 hour; the positive control group is diluted porcine whole blood and 0.9% distilled water (1:5); the negative control group is diluted porcine whole blood and 0.9% normal saline (1:5); no materials are added to both control groups. Then centrifuge at a speed of 3000 revolutions per minute for 10 minutes; analyze the supernatant by enzyme-linked immunosorbent assay to reflect the influence of Example 1, Comparative Example 1, and Comparative Example 2 on hemolysis. Calculate the hemolysis index (H.I.) as follows:

[0100]

[0101] In the formula, A m is the absorbance of the experimental group, A nc is the absorbance of the negative control group, and A pc is the absorbance of the positive control group.

[0102] The hemolysis rate of Example 1 is calculated to be 0.2%, and the sutures obtained in the present invention have good biocompatibility with blood (see Figure 5 ).

[0103] 7) Animal experiment

[0104] Male rats weighing between 400 and 500 g were selected, anesthetized, and a midline laparotomy was performed to expose the abdominal aorta. The abdominal aorta was carefully transected, and a polycaprolactone-heparin suture was used for vascular suture to repair the artery. Postoperative observations showed that the blood vessels of the rats treated with the polycaprolactone-heparin suture grew and healed well, and no thrombus was found. The experimental results indicate that the present invention has good biocompatibility, strong anticoagulant properties, and good mechanical properties, and can be well applied to small-diameter vascular suture surgery, having significant advantages in reducing the risk of postoperative complications and promoting healing.

[0105] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention. The above embodiments are only for clearly illustrating the examples and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Therefore, the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A high-strength, anti-coagulation suture, characterized in that: The suture thread is made of heparin-modified polycaprolactone as a raw material and is stretched after heating; wherein the heparin-modified polycaprolactone is obtained by grafting reaction of heparin / coupling agent / buffer solution and polycaprolactone solution as main raw materials.

2. The suture according to claim 1, characterized in that: The coupling agent comprises N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride.

3. The suture according to claim 1, characterized in that: The mass ratio of the introduced heparin, coupling agent and polycaprolactone is 1:0.2-0.5:1.0-2.

0.

4. The suture according to claim 1, characterized in that: The molecular weight of the polycaprolactone is 10,000-80,000; the molecular weight of heparin is 8,000-15,000.

5. The suture according to claim 1, characterized in that: The diameter is 0.025~0.05mm.

6. The method for preparing a suture according to any one of claims 1 to 5, characterized in that: The steps include: 1) adding the polycaprolactone solution to the heparin / coupling agent / buffer solution, heating the solution under stirring, and removing the solvent by spin drying; 2) dissolving the product obtained in step 1) with hexafluoroisopropanol, washing with water, and drying to obtain heparin-modified polycaprolactone; 3) The obtained heparin-modified polycaprolactone is heated in a water bath, stretched, dried and sterilized to obtain the high-strength, anti-coagulation suture thread.

7. The preparation method according to claim 6, characterized in that: In the heparin / coupling agent / buffer solution, the concentration of heparin is 0.04-0.1 g / mL, the concentration of the coupling agent is 0.03-0.08 g / mL, and the pH value is 5-7.

5.

8. The preparation method according to claim 6, characterized in that: The concentration of the polycaprolactone solution is 0.12-0.225 g / mL.

9. The preparation method according to claim 6, characterized in that: The volume ratio of the heparin / coupling agent / buffer solution to the polycaprolactone solution is 1:(1.5-3.0).

10. The preparation method according to claim 6, characterized in that: The traction and stretching step adopts a step-by-step temperature-controlled traction process, and the specific steps include: in a water bath condition of 75 to 85° C., pulling out the softened heparin-modified polycaprolactone at a speed of 0.5 to 1.0 cm / s to obtain a thick line segment with a diameter of 0.75 to 1.5 mm; then placing the obtained thick line segment in an environment of 0 to 30° C., and continuing to stretch it at a speed of 0.5 to 1.0 mm / s to obtain a suture with a diameter of 0.025 to 0.05 mm.

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