Antibacterial and anti-inflammatory absorbable suture line and preparation method thereof

Abstract

The invention discloses an antibacterial and anti-inflammatory absorbable suture line and a preparation method thereof, and relates to the technical field of medical materials. The antibacterial and anti-inflammatory absorbable suture line is prepared from the following raw materials in parts by weight: 55 to 63 parts of polylactic acid, 15 to 20 parts of modified polylactic acid, 15 to 20 parts of hydrophilic modified compatilizer, 10 to 15 parts of polyglycolic acid, 12 to 18 parts of polyethylene glycol and 0.4 to 0.8 part of lubricant, the modified polylactic acid reacts with eugenol through methimazole to generate a thioether compound; then reacting with bromooctadecane to generate a quaternary ammonium salt compound; reacting with L-arginine to obtain an amine methyl phenol compound; and finally reacting with polylactic acid. The antibacterial and anti-inflammatory absorbable suture line prepared by the invention has excellent breaking strength, antibacterial property and hydrophilicity, and can meet the application requirements of clinical medical treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of medical materials, and in particular to an antibacterial and anti-inflammatory absorbable suture thread and a preparation method thereof. Background Art

[0002] Absorbable surgical sutures are specialized threads used during surgical procedures for wound ligation, hemostasis, and tissue closure. They decompose in the human body to form soluble substances that are absorbed and slowly secreted from the body, eliminating the pain and risk of secondary infection associated with postoperative suture removal. Polylactic acid (PLA), a green, biodegradable polymer material, is widely used in absorbable medical sutures due to its excellent biocompatibility and biodegradability. However, PLA sutures do not effectively inhibit bacterial growth, potentially leading to postoperative infection. Furthermore, PLA's hydrophobicity makes it difficult for cells to adhere and reproduce on its surface, which not only slows wound healing but also prolongs its degradation cycle. Due to the polarity difference between the hydrophobic and hydrophilic components of PLA, their compatibility is poor, leading to weak interfacial bonding and phase separation, which compromises the material's mechanical properties. To enhance the safety and reliability of absorbable sutures in clinical applications, optimization and improvement of their antimicrobial and hydrophilic properties are urgently needed.

[0003] Chinese invention patent publication number CN105079868A discloses a highly compatible absorbable medical suture and its preparation method. The method comprises the following steps: S1, preparing suture fibers; S2, preparing a coating solution; and S3, braiding the coating. While the suture exhibits good compatibility with biological tissues, facilitating cell adhesion and growth, and exhibiting excellent mechanical properties, degradation resistance, and ease of operation, it exhibits poor antibacterial properties. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an antibacterial and anti-inflammatory absorbable suture and a preparation method thereof.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions: An antibacterial and anti-inflammatory absorbable suture comprises the following raw materials in parts by weight: 55-63 parts of polylactic acid, 15-20 parts of modified polylactic acid, 15-20 parts of hydrophilic modified compatibilizer, 10-15 parts of polyglycolic acid, 12-18 parts of polyethylene glycol, and 0.4-0.8 parts of lubricant; The modified polylactic acid is prepared by the following method: S1: Methimazole reacts with eugenol to form a sulfide compound; the reaction equation is as follows:

[0006] S2: The sulfide compound reacts with octadecane bromide to form a quaternary ammonium salt compound; the reaction equation is as follows:

[0007] S3: The quaternary ammonium salt compound reacts with L-arginine to obtain an aminomethylphenol compound; the reaction equation is as follows:

[0008] S4: The aminomethylphenol compound reacts with polylactic acid to generate modified polylactic acid; in this reaction, the carboxyl group in the aminomethylphenol compound undergoes an esterification reaction with the hydroxyl group at the end of the polylactic acid.

[0009] In step S1, the molar ratio of methimazole to eugenol is 1:(1.2-1.5).

[0010] In step S2, the molar ratio of the sulfide compound to octadecane bromide is 1:(1.0-1.2).

[0011] In step S3, the molar ratio of the quaternary ammonium salt compound to L-arginine is 1:(1.1-1.3).

[0012] In step S4, the mass ratio of the aminomethylphenol compound to the polylactic acid is 1:(55-60).

[0013] The hydrophilic modified compatibilizer is prepared by the following method: N1: Pentaerythritol reacts with L-lactide to form a four-arm polyester compound; the reaction equation is as follows:

[0014] N2: The four-arm polyester compound reacts with sodium hyaluronate to generate a hydrophilic modified compatibilizer; in the reaction, the hydroxyl group of the four-arm polyester compound reacts with the carboxyl group of sodium hyaluronate to obtain the hydrophilic modified compatibilizer.

[0015] In step N1, the molar ratio of pentaerythritol to L-lactide is 1:24.5.

[0016] In step N2, the mass ratio of the four-arm polyester compound to sodium hyaluronate is 2:5.

[0017] The lubricant is calcium stearate.

[0018] A method for preparing an antibacterial and anti-inflammatory absorbable suture, characterized in that it comprises the following steps: (1) Weigh by weight: 55-63 parts of polylactic acid, 15-20 parts of modified polylactic acid, 10-20 parts of hydrophilic modified compatibilizer, 10-15 parts of polyglycolic acid, 12-18 parts of polyethylene glycol, and 0.4-0.8 parts of lubricant; (2) The above components are added into a high-speed mixer and mixed, and then the mixture is introduced into a twin-screw extruder for extrusion and granulation, and air-cooled to obtain a masterbatch; (3) The masterbatch is added into a melt electrospinning machine for spinning, and then stretched to obtain an antibacterial and anti-inflammatory absorbable suture.

[0019] Due to the adoption of the above technical solution, the beneficial effects of the present invention include: (1) The present invention introduces imidazole ring, quaternary ammonium salt, guanidine group and long-chain alkyl group into polylactic acid through covalent bonds, which not only improves its dispersibility but also destroys bacterial cell membrane through multiple action mechanisms, thereby enhancing the antibacterial properties of absorbable sutures.

[0020] (2) The hydrophilic modified compatibilizer prepared by the present invention improves the breaking strength and hydrophilic properties of the absorbable suture by reducing interfacial tension, forming a three-dimensional network to disperse stress, and acting as a steric hindrance. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0022] Example 1 Preparation of modified polylactic acid: S1: 200 ml of dichloromethane, 0.1 mol of methimazole, and 0.12 mol of eugenol were added to a reaction kettle and stirred to mix. 0.6 g of photoinitiator 184 was added. The mixture was irradiated under 300 W UV light for 5 min with stirring, and then distilled under reduced pressure at 30°C for 2 h to obtain a sulfide compound. Its H NMR spectrum data are as follows: 1 H NMR (300 MHz, DMSO- d 6) δ 7.57 (s, 1H), 7.16 (d, J = 3.6 Hz, 1H), 7.08 (dt, J = 3.6, 0.6 Hz, 1H), 6.79 - 6.62 (m, 3H), 3.83 (s, 3H), 3.71 (d, J = 0.7 Hz, 3H), 3.03 (d, J = 13.0 Hz, 2H), 2.72 (ddd,J = 7.7, 6.8, 0.9 Hz, 2H), 1.91 (tt, J = 7.6, 6.5 Hz, 2H); S2: Add 300 ml of ethyl acetate, 0.1 mol of sulfide compound, and 0.1 mol of octadecane bromide to a reactor, stir and mix, heat to 50°C, react for 15 h, cool to 0°C to precipitate a solid, keep warm for 4 h, filter, and recrystallize using a mixed liquid of 300 ml of ethyl acetate and anhydrous ethanol (volume ratio of ethyl acetate to anhydrous ethanol:8:2), and dry in vacuo at 60°C for 24 h to obtain a quaternary ammonium salt compound; its H NMR spectrum data are as follows: 1 H NMR (300 MHz, DMSO- d 6) δ 7.75 (dd, J = 3.8, 0.6Hz, 1H), 7.66 (d, J = 3.8 Hz, 1H), 7.57 (s, 1H), 6.74 (d, J = 8.7 Hz, 1H), 6.66 (s, 2H), 4.59 (td, J = 5.2, 0.9 Hz, 2H), 3.88 - 3.80 (m, 6H), 3.15 (t, J= 6.1 Hz, 2H), 2.76 - 2.67 (m, 2H), 2.18 (tt, J = 7.7, 5.2 Hz, 2H), 1.93 (tt,J = 7.6, 6.1 Hz, 2H), 1.57 - 1.44 (m, 2H), 1.27 (d, J = 2.5 Hz, 28H), 0.93 -0.82 (m, 3H); S3: 500 ml of deionized water, 0.1 mol of a quaternary ammonium salt compound, and 0.11 mol of L-arginine were added to a reaction kettle, stirred and mixed, and the temperature was raised to 60°C. 12 g of a 37 wt% formaldehyde solution was added dropwise over 30 min. The mixture was reacted for 8 h, cooled to room temperature, and distilled under reduced pressure at 60°C for 3 h. The mixture was then dried under vacuum at 70°C for 24 h to obtain an aminomethylphenol compound. The H NMR spectrum data are as follows: 1 H NMR (300 MHz, DMSO- d6) δ 11.01 (s, 1H), 8.40 (s, 1H), 7.75 (dq, J = 3.8, 0.7 Hz, 1H), 7.66(dt, J = 3.8, 0.8 Hz, 1H), 7.61 (s, 1H), 7.55 (s, 1H), 3.63 (dt, J = 7.8, 6.0 Hz, 1H), 3.25 - 3.07 (m,4H), 2.77 - 2.65 (m, 2H), 2.18 (tt, J = 7.7, 5.2 Hz, 2H), 1.95 (tt, J = 7.5,6.1 Hz, 2H), 1.85 - 1.45 (m, 6H), 1.27 (d, J = 2.5 Hz, 28H), 0.96 - 0.82 (m,3H); S4: Under nitrogen protection, 1000 ml of DMSO, 2 g of aminomethylphenol compound, 1.7 g of N,N-dicyclohexylcarboximide (DCC), and 0.5 g of 4-dimethylaminopyridine (DMAP) were added to the reactor, the temperature was raised to 60 ° C and stirred for 2 h to activate the carboxyl group, 110 g of polylactic acid was added, the reaction was carried out for 48 h, and the mixture was cooled to room temperature and distilled at 80 ° C under reduced pressure for 3 h. Then, 500 ml of dichloromethane was added and stirred to dissolve. 800 ml of anhydrous ethanol was added and stirred to precipitate, which was filtered and dried in a vacuum at 60 ° C for 12 h to obtain modified polylactic acid.

[0023] Example 2 Preparation of modified polylactic acid: S1: Add 200 ml of dichloromethane, 0.1 mol of methimazole, and 0.14 mol of eugenol into a reaction kettle, stir and mix, add 0.6 g of photoinitiator 184, irradiate under 300 W ultraviolet light for 10 min with stirring, and distill under reduced pressure at 30°C for 2 h to obtain a sulfide compound; S2: Add 300 ml of ethyl acetate, 0.1 mol of sulfide compound, and 0.11 mol of octadecane bromide into a reactor, stir and mix, heat to 55°C, react for 14 h, cool to 0°C to precipitate a solid, keep warm for 4 h, filter, and recrystallize using a mixed liquid of 300 ml of ethyl acetate and anhydrous ethanol (volume ratio of ethyl acetate to anhydrous ethanol: 8:2), and dry in a vacuum at 60°C for 24 h to obtain a quaternary ammonium salt compound; S3: 500 ml of deionized water, 0.1 mol of a quaternary ammonium salt compound, and 0.12 mol of L-arginine were added to a reaction kettle, stirred and mixed, and the temperature was raised to 70°C. 12 g of a 37 wt% formaldehyde solution was added dropwise over 30 min. The reaction was continued for 7 h, and the mixture was cooled to room temperature. The mixture was distilled under reduced pressure at 60°C for 3 h, and dried under vacuum at 70°C for 24 h to obtain an aminomethylphenol compound. S4: Under nitrogen protection, 1000 ml of DMSO, 2 g of aminomethylphenol compound, 1.7 g of N,N-dicyclohexylcarboximide (DCC), and 0.5 g of 4-dimethylaminopyridine (DMAP) were added to the reactor, the temperature was raised to 60 ° C and stirred for 2 h to activate the carboxyl group, 116 g of polylactic acid was added, the reaction was carried out for 48 h, and the mixture was cooled to room temperature and distilled at 80 ° C under reduced pressure for 3 h. Then, 500 ml of dichloromethane was added and stirred to dissolve. 800 ml of anhydrous ethanol was added and stirred to precipitate, which was filtered and dried in a vacuum at 60 ° C for 12 h to obtain modified polylactic acid.

[0024] Example 3 Preparation of modified polylactic acid: S1: Add 200 ml of dichloromethane, 0.1 mol of methimazole, and 0.15 mol of eugenol into a reaction kettle, stir and mix, add 0.6 g of photoinitiator 184, irradiate under 300 W ultraviolet light for 15 min under stirring, and distill under reduced pressure at 30°C for 2 h to obtain a sulfide compound; S2: Add 300 ml of ethyl acetate, 0.1 mol of sulfide compound, and 0.12 mol of octadecane bromide into a reactor, stir and mix, heat to 60°C, react for 12 h, cool to 0°C to precipitate a solid, keep warm for 4 h, filter, and recrystallize using a mixed liquid of 300 ml of ethyl acetate and anhydrous ethanol (volume ratio of ethyl acetate to anhydrous ethanol: 8:2), and dry in a vacuum at 60°C for 24 h to obtain a quaternary ammonium salt compound; S3: 500 ml of deionized water, 0.1 mol of a quaternary ammonium salt compound, and 0.13 mol of L-arginine were added to a reaction kettle, stirred and mixed, and the temperature was raised to 75°C. 12 g of a 37 wt% formaldehyde solution was added dropwise over 30 min. The reaction was continued for 6 h, and the mixture was cooled to room temperature. The mixture was distilled under reduced pressure at 60°C for 3 h, and dried under vacuum at 70°C for 24 h to obtain an aminomethylphenol compound. S4: Under nitrogen protection, 1000 ml of DMSO, 2 g of aminomethylphenol compound, 1.7 g of N,N-dicyclohexylcarboximide (DCC), and 0.5 g of 4-dimethylaminopyridine (DMAP) were added to the reactor, the temperature was raised to 60 ° C and stirred for 2 h to activate the carboxyl group, 120 g of polylactic acid was added, the reaction was carried out for 48 h, and the mixture was cooled to room temperature and distilled at 80 ° C under reduced pressure for 3 h. Then, 500 ml of dichloromethane was added and stirred to dissolve. 800 ml of anhydrous ethanol was added and stirred to precipitate, which was filtered and dried in a vacuum at 60 ° C for 12 h to obtain modified polylactic acid.

[0025] Example 4 Preparation of hydrophilic modified compatibilizer: N1: Under nitrogen protection, 1000 ml of DMF, 2.45 mol of L-lactide, 0.1 mol of pentaerythritol, and 6 g of stannous octoate were added to a reactor, stirred for 20 min, heated to 130°C for 5 h, cooled to room temperature, and distilled under reduced pressure at 80°C for 3 h. 600 ml of chloroform was added and stirred to dissolve. 1000 ml of methanol was added and stirred to precipitate a solid, which was filtered and dried in vacuo at 65°C for 10 h to obtain a four-arm polyester compound with a number average molecular weight of 3428. N2: Put 1000g deionized water and 10g sodium hyaluronate into a reactor, stir to dissolve, add 12g strong acid cation exchange resin, stir at room temperature for 5h, filter, adjust the pH of the filtrate to 7 with tetrabutylammonium hydroxide, add 2000ml anhydrous ethanol, stir to precipitate solid, filter, vacuum dry at 60℃ for 24h, dissolve in 300ml anhydrous DMSO, add 4.5g N,N-dicyclohexylcarboximide (DCC) and 1g 4-dimethylaminopyridine (DMAP), stir at 60℃ for 2h to activate the carboxyl group, add 4g four-arm polyester compound, react at 60℃ for 48h, cool to room temperature, filter, add 500ml acetone, stir to precipitate solid, filter, and vacuum dry at 60℃ for 12h to obtain a hydrophilic modified compatibilizer.

[0026] Example 5 Preparation of antibacterial and anti-inflammatory absorbable sutures: (1) Weigh: 550 g of polylactic acid, 150 g of modified polylactic acid (prepared in Example 1), 150 g of hydrophilic modified compatibilizer (prepared in Example 4), 100 g of polyglycolic acid, 120 g of polyethylene glycol, and 4 g of calcium stearate; (2) The above components were added to a high-speed mixer and mixed at a mixing temperature of 170°C, a mixing speed of 80 r / min, and a mixing time of 20 min. The mixed material was then introduced into a twin-screw extruder for extrusion granulation. The screw speed of the screw extruder was 10 r / s, the conveying section temperature of the twin-screw extruder was 170°C, the melting section temperature was 180°C, the mixing section temperature was 185°C, and the homogenizing section temperature was 170°C. The mixture was then air-cooled to obtain a masterbatch. (3) The masterbatch was added to a melt electrospinning machine at a spinning temperature of 210 °C and a spinning speed of 180 m / min to obtain a primary fiber with a diameter of 1 mm. The fiber was then stretched 3 times in a water bath at 70 °C to obtain an antibacterial and anti-inflammatory absorbable suture with a diameter of 0.4 mm.

[0027] Example 6 Preparation of antibacterial and anti-inflammatory absorbable sutures: (1) Weigh: 600 g of polylactic acid, 180 g of modified polylactic acid (prepared in Example 2), 190 g of hydrophilic modified compatibilizer (prepared in Example 4), 120 g of polyglycolic acid, 160 g of polyethylene glycol, and 6 g of calcium stearate; (2) The above components were added to a high-speed mixer and mixed at a mixing temperature of 170°C, a mixing speed of 80 r / min, and a mixing time of 20 min. The mixed material was then introduced into a twin-screw extruder for extrusion granulation. The screw speed of the screw extruder was 10 r / s, the conveying section temperature of the twin-screw extruder was 170°C, the melting section temperature was 180°C, the mixing section temperature was 185°C, and the homogenizing section temperature was 170°C. The mixture was then air-cooled to obtain a masterbatch. (3) The masterbatch was added to a melt electrospinning machine at a spinning temperature of 210 °C and a spinning speed of 180 m / min to obtain a primary fiber with a diameter of 1 mm. The fiber was then stretched 3 times in a water bath at 80 °C to obtain an antibacterial and anti-inflammatory absorbable suture with a diameter of 0.4 mm.

[0028] Example 7 Preparation of antibacterial and anti-inflammatory absorbable sutures: (1) Weigh: 630 g of polylactic acid, 200 g of modified polylactic acid (prepared in Example 3), 200 g of hydrophilic modified compatibilizer (prepared in Example 4), 150 g of polyglycolic acid, 180 g of polyethylene glycol, and 8 g of calcium stearate; (2) The above components were added to a high-speed mixer and mixed at a mixing temperature of 170°C, a mixing speed of 80 r / min, and a mixing time of 20 min. The mixed material was then introduced into a twin-screw extruder for extrusion granulation. The screw speed of the screw extruder was 10 r / s, the conveying section temperature of the twin-screw extruder was 170°C, the melting section temperature was 180°C, the mixing section temperature was 185°C, and the homogenizing section temperature was 170°C. The mixture was then air-cooled to obtain a masterbatch. (3) The masterbatch was added to a melt electrospinning machine at a spinning temperature of 210 °C and a spinning speed of 180 m / min to obtain a primary fiber with a diameter of 1 mm. The fiber was then stretched 3 times in a water bath at 90 °C to obtain an antibacterial and anti-inflammatory absorbable suture with a diameter of 0.4 mm.

[0029] Comparative Example 1 The raw material composition and process of the antibacterial and anti-inflammatory absorbable suture are basically the same as those in Example 6, except that the modified polylactic acid (prepared in Example 2) added to the components is replaced with an equal mass of a mixture prepared by the following method: The aminomethylphenol compound (prepared in step S3 of Example 2) and polylactic acid were mixed at a mass ratio of 1:58 to obtain a mixture.

[0030] Comparative Example 2 The raw material composition and process of the antibacterial and anti-inflammatory absorbable suture are basically the same as those in Example 6, except that the modified polylactic acid (prepared in Example 2) added to the components is replaced with an equal mass of modified polylactic acid prepared by the following method: The preparation method of modified polylactic acid is basically the same as that of Example 2, except that the methimazole in step S1 is replaced by an equimolar amount of 6-(dimethylamino)hexane-1-thiol (CAS: 68402-57-3).

[0031] Comparative Example 3 The raw material composition and process of the antibacterial and anti-inflammatory absorbable suture are basically the same as those in Example 6, except that the modified polylactic acid (prepared in Example 2) added to the components is replaced with an equal mass of modified polylactic acid prepared by the following method: The preparation method of the modified polylactic acid is substantially the same as that of Example 2, except that the L-arginine in step S3 is replaced by an equimolar amount of glycine.

[0032] Comparative Example 4 The raw material composition and process of the antibacterial and anti-inflammatory absorbable suture are basically the same as those in Example 6, except that the modified polylactic acid (prepared in Example 2) added to the components is replaced with an equal mass of modified polylactic acid prepared by the following method: S1: Add 200 ml of dichloromethane, 0.1 mol of methimazole, and 0.14 mol of eugenol into a reaction kettle, stir and mix, add 0.6 g of photoinitiator 184, irradiate under 300 W ultraviolet light for 10 min with stirring, and distill under reduced pressure at 30°C for 2 h to obtain a sulfide compound; S2: Add 500 ml of deionized water, 0.1 mol of sulfide compound, and 0.12 mol of L-arginine to a reactor, stir and mix, heat to 70°C, add 12 g of 37 wt% formaldehyde solution dropwise for 30 min, react for 7 h, cool to room temperature, distill under reduced pressure at 60°C for 3 h, and dry under vacuum at 70°C for 24 h to obtain an aminomethylphenol compound; S3: Under nitrogen protection, 1000 ml of DMSO, 2 g of aminomethylphenol compound, 1.7 g of N,N-dicyclohexylcarboximide (DCC), and 0.5 g of 4-dimethylaminopyridine (DMAP) were added to the reactor, the temperature was raised to 60 ° C and stirred for 2 h to activate the carboxyl group, 116 g of polylactic acid was added, the reaction was continued for 48 h, and the mixture was cooled to room temperature and distilled at 80 ° C under reduced pressure for 3 h. Then, 500 ml of dichloromethane was added and stirred to dissolve. 800 ml of anhydrous ethanol was added and stirred to precipitate, which was filtered and dried in a vacuum at 60 ° C for 12 h to obtain modified polylactic acid.

[0033] Comparative Example 5 The raw material composition and process of the antibacterial and anti-inflammatory absorbable suture are basically the same as those in Example 6, except that the hydrophilic modified compatibilizer (prepared in Example 4) added to the components is replaced with an equal mass of a mixture prepared by the following method: The four-arm polyester compound (prepared in step N1 of Example 4) and sodium hyaluronate were mixed in a mass ratio of 2:5 to obtain a mixture.

[0034] Comparative Example 6 The raw material composition and process of the antibacterial and anti-inflammatory absorbable suture are basically the same as those in Example 6, except that the hydrophilic modified compatibilizer (prepared in Example 4) added to the components is replaced with an equal mass of a hydrophilic modified compatibilizer prepared by the following method: The preparation method of the hydrophilic modified compatibilizer is substantially the same as that of Example 4, except that the L-lactide in step N1 is replaced by an equimolar amount of 6-caprolactone.

[0035] Comparative Example 7 The raw material composition and process of the antibacterial and anti-inflammatory absorbable suture are basically the same as those in Example 6, except that the hydrophilic modified compatibilizer (prepared in Example 4) added to the components is replaced with an equal mass of a hydrophilic modified compatibilizer prepared by the following method: The preparation method of the hydrophilic modified compatibilizer is substantially the same as that of Example 4, except that the pentaerythritol in step N1 is replaced by an equimolar amount of ethylene glycol.

[0036] The PLA used in the examples and comparative examples of the present application is of model JHMS®PL05 (number average molecular weight of 32 kDa), and the polyglycolic acid is of model JHMS®PG15, produced by Sichuan Zhuoxin Biomaterials Research Co., Ltd.; the polyethylene glycol is PEG2000; the sodium hyaluronate is cosmetic grade with a viscosity-average molecular weight of 11 kDa, produced by Zhenjiang Dongyuan Biotechnology Co., Ltd.; the strong acid cation exchange resin is a polymer of divinylbenzene and sodium vinylbenzenesulfonate, and the brand is Amberlite® IMAC HP1110 resin.

[0037] The antibacterial and anti-inflammatory absorbable sutures prepared in Examples 5-7 and Comparative Examples 1-7 were subjected to breaking strength, antibacterial performance tests, and water absorption tests. The test results are shown in Table 1.

[0038] The breaking strength was tested using an electronic single fiber strength meter. The test conditions were as follows: the suture was cut into 20 cm pieces, the clamping distance was 12.5 cm, the stretching speed was 20 mm / min, and the suture was stretched until it broke completely. The breaking strength was obtained. The test was repeated 3 times and the average value was taken.

[0039] Antibacterial performance test: The sutures were cut into 5 cm / root, and the test bacteria were Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The 5 cm / root sutures were mixed with a density of 1×10 8A bacterial suspension of 100 CFU / mL was co-cultured on an agar-coated Petri dish. The dish was placed in a 37°C incubator for 24 hours. The outer width D of the inhibition zone and the sample diameter d (0.4 mm) were measured. Three replicates were measured, the average was taken, and the inhibition zone width was calculated as: H = (Dd) / 2.

[0040] Water absorption test: Cut sutures into 5cm pieces, grouping 20 pieces. Dry in a 50°C oven for 24 hours, then weigh m0. Soak the specimens in 37°C distilled water for 24 hours. Remove the specimens and quickly wipe off all surface water with a clean, dry cloth or filter paper. Reweigh each specimen m1. Measure three replicates, average the data, and calculate the water absorption R = (m1 - m0) / m1 × 100%.

[0041] Table 1 Performance test data table

[0042] It can be seen from Examples 5, 6 and 7 in Table 1 that the antibacterial and anti-inflammatory absorbable sutures prepared by the present invention have excellent breaking strength, antibacterial properties and hydrophilicity.

[0043] The modified polylactic acid prepared by the present invention contains an imidazole ring, a quaternary ammonium salt, a guanidine group, and a long-chain alkyl group. These groups are covalently bonded to the polylactic acid structure, improving its dispersibility within the polylactic acid matrix and enhancing its antibacterial properties. The quaternary ammonium salt cations and the positively charged guanidine group adsorb onto the negatively charged bacterial cell membrane surface through electrostatic attraction, interfering with the function of proteins (such as transporters and enzymes) on the cell membrane and weakening its barrier function. Furthermore, the guanidine group inhibits the activity of enzymes (such as adenosine triphosphatase (ATPase)) on the cell membrane, affecting their metabolism and thereby inhibiting bacterial growth and reproduction. The three-dimensional structure of the imidazole ring expands the contact area between the molecule and the cell membrane, exacerbating the disorder of phospholipid molecules and accelerating cell membrane disintegration. The long-chain alkyl group can penetrate into and disrupt the lipid bilayer structure of the cell membrane through hydrophobic interactions, disrupting its order.

[0044] The polyester structure in the hydrophilic modified compatibilizer prepared in this application has good compatibility with the polylactic acid matrix, can reduce the interfacial tension between the two phases, and promote interfacial fusion; the four-arm star topology forms a three-dimensional entangled network with the polylactic acid molecular chain, which can effectively improve the breaking strength through stress dispersion; at the same time, the steric hindrance effect of the four-arm structure can prevent the sodium hyaluronate structure from agglomerating in the polylactic acid matrix; so that the material has good hydrophilic properties. The difference between the hydrophilic modified compatibilizer used in Comparative Example 6 and Example 6 is that the poly-L-lactide segment is replaced with a poly-6-caprolactone segment. Both are hydrophobic segments and have little effect on water absorption. Compared with the poly-L-lactide segment, the poly-6-caprolactone segment has poor compatibility with the polylactic acid matrix, resulting in a decrease in breaking strength.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. However, any equivalent changes, modifications and evolutions made by ordinary technicians in this field without departing from the scope of the technical solution of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. An antibacterial and anti-inflammatory absorbable suture, characterized in that: The composition comprises the following raw materials in parts by weight: 55-63 parts of polylactic acid, 15-20 parts of modified polylactic acid, 15-20 parts of hydrophilic modified compatibilizer, 10-15 parts of polyglycolic acid, 12-18 parts of polyethylene glycol, and 0.4-0.8 parts of lubricant; The modified polylactic acid is prepared by the following method: S1: Methimazole reacts with eugenol to form a sulfide compound; S2: The sulfide compound reacts with octadecane bromide to form a quaternary ammonium salt compound; S3: The quaternary ammonium salt compound reacts with L-arginine to obtain an aminomethylphenol compound; S4: The aminomethylphenol compound reacts with polylactic acid to generate modified polylactic acid.

2. The antibacterial and anti-inflammatory absorbable suture according to claim 1, characterized in that: In step S1, the molar ratio of methimazole to eugenol is 1:(1.2-1.5).

3. The antibacterial and anti-inflammatory absorbable suture according to claim 1, characterized in that: In step S2, the molar ratio of the sulfide compound to octadecane bromide is 1:(1.0-1.2).

4. The antibacterial and anti-inflammatory absorbable suture according to claim 1, characterized in that: In step S3, the molar ratio of the quaternary ammonium salt compound to L-arginine is 1:(1.1-1.3).

5. The antibacterial and anti-inflammatory absorbable suture according to claim 1, characterized in that: In step S4, the mass ratio of the aminomethylphenol compound to the polylactic acid is 1:(55-60).

6. The antibacterial and anti-inflammatory absorbable suture according to claim 1, characterized in that: The hydrophilic modified compatibilizer is prepared by the following method: N1: Pentaerythritol reacts with L-lactide to form a four-arm polyester compound; N2: The four-arm polyester compound reacts with sodium hyaluronate to form a hydrophilic modified compatibilizer.

7. The antibacterial and anti-inflammatory absorbable suture according to claim 6, characterized in that: In step N1, the molar ratio of pentaerythritol to L-lactide is 1:24.

5.

8. The antibacterial and anti-inflammatory absorbable suture according to claim 6, characterized in that: In step N2, the mass ratio of the four-arm polyester compound to sodium hyaluronate is 2:

5.

9. The antibacterial and anti-inflammatory absorbable suture according to claim 1, characterized in that: The lubricant is calcium stearate.

10. A method for preparing the antibacterial and anti-inflammatory absorbable suture according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Weigh by weight: 55-63 parts of polylactic acid, 15-20 parts of modified polylactic acid, 10-20 parts of hydrophilic modified compatibilizer, 10-15 parts of polyglycolic acid, 12-18 parts of polyethylene glycol, and 0.4-0.8 parts of lubricant; (2) The above components are added into a high-speed mixer and mixed, and then the mixture is introduced into a twin-screw extruder for extrusion and granulation, and air-cooled to obtain a masterbatch; (3) The masterbatch is added into a melt electrospinning machine for spinning, and then stretched to obtain an antibacterial and anti-inflammatory absorbable suture.

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