WO2017028626A1

WO2017028626A1 - Absorbable surgical suture and preparation method therefor

Info

Publication number: WO2017028626A1
Application number: PCT/CN2016/087457
Authority: WO
Inventors: 吴奕光; 薛清辉; 江长兵; 黎剑辉; 吴灿光
Original assignee: 深圳市阳光之路生物材料科技有限公司
Priority date: 2015-08-19
Filing date: 2016-06-28
Publication date: 2017-02-23
Also published as: CN105133088A; CN105133088B

Abstract

Disclosed are an absorbable surgical suture and a preparation method therefor. The preparation method comprises the following steps: S1, dissolving squid cartilage chitosan to obtain a spinning solution, the deacetylation degree of the squid cartilage chitosan being greater than 60%, and the molecular weight of the squid cartilage chitosan being greater than 0.5*106; and S2, spinning the spinning solution and then drying to obtain the absorbable surgical suture. The absorbable surgical suture prepared by the method has a mechanical property reaching the requirements of clinical application, can be gradually absorbed by a human body and effectively promote the healing of a wound tissue, and has a better application prospect.

Description

Absorbable surgical suture and preparation method thereof

Technical field

The invention relates to the technical field of biological materials, in particular to an absorbable surgical suture and a preparation method thereof.

Background technique

Surgical sutures have a long history and can be divided into non-absorbable surgical sutures and absorbable surgical sutures according to their performance. The biggest disadvantage of non-absorbable surgical sutures is that the wounds need to be removed after healing, and there are different degrees of tissue reaction. The sutures are easy to leave scars, so they are limited in many surgical operations, especially for sutures of internal tissues. Since the beginning of the 20th century, many developed countries in the world have begun to study absorbable surgical sutures, such as the gut, silk thread and PGA line, which have been applied in practical clinical practice. The absorbable surgical suture can be degraded and absorbed in the human body. It avoids the pain caused by the second operation, and can choose different absorbable surgical sutures according to the actual surgery needs. In China, the research on absorbable surgical sutures started relatively late. The research mainly focused on the synthesis, spinning, in vitro degradation and animal experiments of polyglycolide, polyethyl lactide and polylactic acid. But so far, most of these studies are in the laboratory stage, and there are still many key technologies to be solved. So far, the absorbable surgical sutures used in most surgical operations in domestic hospitals are mainly imported silk, PGLA lines and gut lines.

The domestic patent "Preparation Process of a Chitosan Surgical Suture" (Publication No. CN03129976.6) discloses a preparation process of a chitosan surgical suture, firstly pouring a chitosan solution into a flat glass tank, Dry at a certain temperature to form a film, cut the film into strips with a mold, put it in a NaOH solution or a mixture of NaOH and ethanol for 5-10 minutes, then rinse with pure water to dry the chitosan suture thick line. Then, the chitosan suture thick line is placed in a saturated solution of chitosan for a period of time, and then taken out, twisted into a filament on a silk reeling machine, stretched and dried, and then immersed in a NaOH solution for 5 to 30 minutes to be taken out, and washed with pure water. Clean is the finished suture. The domestic patent "a chitosan surgical suture and its manufacturing process" (Application No. 201010218130.4) discloses a chitosan surgical suture and a manufacturing process thereof, firstly drying a chitosan solution into a film, and the film is in a mold Cut into strips, then put into a mixed solution of NaOH and ethanol The medium is heated, and the mixed solution is raised from 60 ° C to 80 ° C and then lowered to 60 ° C. After the pulsed heating for 60 to 120 minutes, the thick line is sutured by chitosan surgery. Then, the chitosan was sutured and the thick wire was subjected to drawing and coating to obtain a chitosan surgical suture. The above two processes are first made after film making, the production process is complicated, the cost is high, the cross section of the suture is not smooth enough, the friction resistance is large, the tensile strength is not enough, and the clinical application value is not high. The domestic patent "an absorbable surgical suture and a preparation method thereof" (Application No. 201110387194.1) discloses an absorbable surgical suture and a preparation method thereof, firstly dissolving chitosan in an acetic acid solution, and then adding urea And glycerin, fully stirred, filtered, defoamed to obtain a spinning solution; then the wet spinning method to prepare chitosan surgical suture thick line, after washing and drying, oil drying and other post-treatment, to obtain absorbable surgery Suture. Glycerin and urea components are added to the process, resulting in poor biocompatibility of the suture, easy to produce foreign body reaction, and tensile strength is difficult to meet clinical application requirements. The domestic patent "Preparation method of aliphatic polyester-chitosan composite fiber tissue repair scaffold" (Application No. 200810051315) discloses chitosan (Chitosan) as a partial deacetylated product of chitin, which has a polyglycan (GAG) Similar chemical structures and many excellent properties for tissue engineering scaffolding materials. However, like other natural macromolecules, chitosan has poor mechanical properties in supporting tissue cells. As natural macromolecules and synthetic polyester composites are gradually used in tissue engineering, the mixing of chitosan with synthetic polyester with good mechanical properties can effectively improve the mechanical properties of the materials. The fly in the ointment is that this method sacrifices many amino groups and hydroxyl groups on chitosan, and these groups are active groups with improved cell adhesion.

Summary of the invention

The object of the present invention is to provide an absorbable surgical suture and a preparation method thereof, which solve the technical problems that the prior art has a complicated preparation process, and the biocompatibility and mechanical properties cannot be obtained.

To this end, the present invention provides a method of preparing an absorbable surgical suture comprising the following steps:

S1, the squid cartilage chitosan is dissolved to obtain a spinning dope; wherein the squid cartilage chitosan has a degree of deacetylation greater than 60% and a molecular weight greater than 0.5×10 ⁶ ;

S2, drying the spinning dope and drying to obtain the absorbable surgical suture.

Preferably, the spinning in step S2 is wet spinning.

Preferably, the wet spinning comprises the steps of: feeding the spinning dope into a spinneret having an inner diameter of 0.1 to 1.0 mm through a metering pump, and extruding the spinning dope with a pressing force of 10 to 100 N; In the coagulation bath To chitosan monofilament;

Wherein, the components of the coagulation bath comprise, by mass percentage, 4% to 6% of sodium hydroxide, 1% to 3% of ethanol, and the rest are deionized water.

Preferably, in step S1, the squid cartilage chitosan is dissolved in a solvent at a ratio of solid to liquid of 1.0:100 to 5.0:100 g/ml to obtain a spinning dope.

Preferably, the solvent is acetic acid having a mass percent concentration of 2%.

Preferably, before the spinning of the spinning dope in step S2, the spinning dope is further filtered and defoamed.

Preferably, the preparation of the salmon cartilage chitosan in step S1 comprises the following steps:

S11. The squid cartilage β-chitin is dissolved in a NaOH solution having a mass percentage concentration of 30% to 40% at a ratio of solid to liquid of 5.0:100 to 25:100 g/ml, and stirred at 50 to 80 ° C for 1 to 6 hours. After filtration, the first filter residue is obtained;

S12. The first filter residue is washed to neutral and then dried to obtain a first salmon cartilage chitosan as the salmon cartilage chitosan of step S1.

Preferably, after step S12, the following steps are further included:

S13, the first squid cartilage chitosan obtained in step S12 is used as a first intermediate product, and the first intermediate product is dissolved in a mass percentage concentration at a ratio of solid to liquid ratio of 5.0:100 to 25:100 g/ml. 30% ~ 40% of the NaOH solution, stirred at 50 ~ 80 ° C for 1 ~ 6h and then filtered to obtain a second filter residue;

S14. The second filter residue is washed to neutrality and then dried to obtain a second salmon cartilage chitosan having a different degree of deacetylation from the first intermediate product as the salmon cartilage chitosan of step S1.

Preferably, after step S12 or step S14, the following steps are further included:

S15, the first squid cartilage chitosan obtained in step S12 or the second squid cartilage chitosan obtained in step S14 is used as a second intermediate product at a solid-liquid ratio of 5.0:100 to 25:100 g/ml. Proportion, the second intermediate product is dissolved in a hydrochloric acid solution having a mass percentage concentration of 1% to 5% at room temperature, and sonicated at 60 to 80 ° C for 2 to 8 hours to obtain a mixed solution;

S16, adding 0.1~1.0 mol/L NaOH solution to the mixture to adjust the mixture to neutrality, and suction filtration to obtain a third filter residue;

S17. The third filter residue is washed to neutrality and then dried to obtain a third salmon cartilage chitosan having a molecular weight different from that of the second intermediate product, as the salmon cartilage chitosan of step S1.

The present invention also provides an absorbable surgical suture that can be made using any of the above-described methods of preparing an absorbable surgical suture.

Chitin is divided into three crystal forms: α, β, and γ. Among them, β-chitin is mainly distributed in mollusks and diatoms. Compared with α-chitin, only β-chitin is present in the molecule. Hydrogen bonds, and hydrogen bonds are weak, the structure is more loose, so β-chitin has higher reactivity. Β-chitin has not only the safe, non-toxic, natural and biodegradable properties of α-chitin, but also has higher affinity for various solvents and is easier to chemically modify than α-chitin. The squid cartilage chitosan and shrimp and crab chitosan prepared by deacetylation of squid cartilage β-chitin are the only cationic aminopolysaccharides in nature, which not only have natural bioregeneration, biodegradability, and biological phase. Capacitive and antibacterial properties, and the absorbable surgical sutures prepared from the specific molecular weight squid cartilage chitosan (MW>0.5×10 ⁶ ) are better in mechanical properties and can be gradually absorbed by the human body, effectively promoting wound tissue. Healing.

The invention adopts a specific molecular weight and deacetylation degree of squid cartilage chitosan (DD>60%, MW>0.5×10 ⁶ ) as a raw material, and the monofilament chitosan can be absorbed by the wet spinning technique to absorb the surgical suture. It has a diameter of 0.05 to 0.50 mm, a tensile strength of 10 to 80 N, and an elongation at break of 3% to 15%. It has better toughness and tensile strength than other chitosan surgical sutures, and has a more uniform diameter. The surface is smoother and the cross section is more rounded, which greatly improves the tensile strength of the surgical suture, and solves the problem of insufficient mechanical properties of the biomaterial as a medical absorbable surgical suture; in addition, the absorbable surgical suture only contains the squid cartilage Chitosan has good biocompatibility and human absorbable properties, which avoids the pain of patient's suture removal, and the surgical suture has no inflammatory reaction to surrounding tissues, which can effectively promote the healing of wound tissue, and can be widely used in surgery. Wound ligation, suturing, hemostasis, and suturing of other tissues.

detailed description

The preparation method of an absorbable surgical suture according to the present invention comprises the following steps:

S1, according to the ratio of solid-liquid ratio of 1.0:100-5.0:100g/ml, the chitosan chitosan having a degree of deacetylation of more than 60% and a molecular weight of more than 0.5×10 ⁶ is dissolved to obtain a spinning dope;

S2. The spinning and defoaming spinning dope is wet-spun, dried and stretched to obtain an absorbable surgical suture.

Wherein, the preparation of the squid cartilage chitosan in step S1 comprises:

S11. According to the ratio of solid to liquid ratio of 5.0:100 to 25:100 g/ml, the cartilage cartilage β-chitin or squid is soft. The chitosan is dissolved in a NaOH solution having a mass percentage concentration of 30% to 40%, stirred at 50 to 80 ° C for 1 to 6 hours, and then filtered to obtain a filter residue;

S12. The filter residue obtained in the step S11 is washed to neutrality and then dried to obtain the squid cartilage chitosan used in the step S1.

The degree of deacetylation of squid cartilage chitosan was determined by elemental analysis, and the viscosity average molecular weight of squid cartilage chitosan was determined by a dilute solution viscosity method to obtain a series of squid cartilage chitosan as shown in Table 1 below. It can be seen from Table 1 that using different deacetylation conditions (such as alkali concentration, time, temperature), the obtained chimon cartilage chitosan has similar molecular weights and different degrees of deacetylation.

Table 1

among them,

--chitin: salmon cartilage β-chitin;

2+1 ^a : deacetylation twice, the first 2h, the second 1h;

2+1+1 ⁶ : three times of deacetylation, the first 2h, the second 1h, the third 1h;

1+1+1+1+1 ^c : deacetylation five times, each time 1h;

CS-75 ^d : CS-75 was sonicated at 70 ° C for 2 h;

Nil ^e : Not completely dissolved, the viscosity average molecular weight could not be determined.

Further, the preparation of the squid cartilage chitosan further comprises, after step S12:

S13. Taking the squid cartilage chitosan obtained in step S12 as an intermediate product, the ratio of solid to liquid is 5.0:100. ～25:100g/ml ratio, the intermediate product is dissolved in a hydrochloric acid solution having a mass percentage concentration of 1% to 5% at room temperature, and sonicated at 60 to 80 ° C for 2 to 8 hours to obtain a mixed solution;

S14, adding 0.1~1.0mol/L NaOH solution to the mixture to adjust the mixture to neutrality, and suction filtration to obtain filter residue;

S15. The filter residue obtained in the step S14 is washed to neutrality and then dried to obtain a squid cartilage chitosan having a molecular weight different from that of the intermediate product, which is used as the squid cartilage chitosan used in the step S1.

The degree of deacetylation of squid cartilage chitosan was determined by elemental analysis. The viscosity average molecular weight of squid cartilage chitosan was determined by dilute solution viscosity method, and a series of squid cartilage chitosan as shown in Table 2 below were obtained. As can be seen from Table 2, by changing the sonication time and/or temperature, the obtained cartilage chitosan has a similar degree of deacetylation and a different molecular weight.

Table 2

among them,

--chitin: salmon cartilage β-chitin;

CS-150: DD (80.00 ± 0.65)%, MW (1.52 ± 0.25) × 10 ⁶ carp cartilage chitosan.

The invention is described in detail below by means of preferred embodiments.

Embodiment 1:

S1, 2.0g of squid cartilage chitosan (DD=75.70%, MW=1.20×10 ⁶ ) powder was dissolved in 50ml, 2% by mass concentration of acetic acid solution, stirred under the action of magnetic stirrer for 2h, to be completely After dissolution, a spinning dope is obtained;

S2. After filtering and defoaming the spinning dope, a spinneret with an inner diameter of 0.8 mm is input through a metering pump. Pressing the spinning dope into the coagulation bath to obtain the chitosan monofilament; wherein the mass percentage of each component of the coagulation bath comprises: sodium hydroxide 4%, ethanol 2%, and the rest is deionized water;

S3. The chitosan monofilament was soaked in deionized water to neutrality, and then stretched at room temperature for 10 N and dried for 1 day to obtain a novel chitosan absorbable surgical suture monofilament.

Wherein, the preparation of the squid cartilage chitosan powder in step S1 comprises:

S11, in a solid-liquid ratio of 5.0:100g / ml ratio, the salmon cartilage β-chitin is dissolved in a mass percentage concentration of 34% NaOH solution, stirred at 80 ° C for 2h and filtered to obtain filter residue;

S12. The filter residue is washed with deionized water until neutral, and then dried and ground to obtain a squid cartilage chitosan powder.

The surgical suture prepared in this example has a diameter of 0.27 mm, a tensile strength of 45.47 N, and a tensile elongation at break of 14.13%.

Embodiment 2:

S1, 2.2g of squid cartilage chitosan (DD=79.99%, MW=1.15×10 ⁶ ) powder was dissolved in 50ml, 2% by mass concentration of acetic acid solution, stirred under the action of magnetic stirrer for 2h, to be completely After dissolution, a spinning dope is obtained;

S2. After filtering and defoaming the spinning dope, a spinning nozzle with an inner diameter of 0.5 mm is input through a metering pump, and the spinning dope is squeezed into a coagulation bath by a pressure of 60 N to obtain a chitosan monofilament; wherein, each group of the coagulation bath The mass percentage of the fraction includes: 6% sodium hydroxide, 1% ethanol, and the rest is deionized water;

S11, in a solid-liquid ratio of 25:100g / ml ratio, the salmon cartilage β-chitin is dissolved in a mass percentage concentration of 30% NaOH solution, stirred at 50 ° C for 6h and filtered to obtain filter residue;

The surgical suture prepared in this example has a diameter of 0.29 mm, a tensile strength of 45.17 N, and a tensile elongation at break of 14.13%.

Embodiment 3:

S1, 1.0 g of squid cartilage chitosan (DD=84.48%, MW=1.13×10 ⁶ ) powder was dissolved in 50 ml of 2% by mass acetic acid solution, stirred under the action of a magnetic stirrer for 2 h, to be completely After dissolution, a spinning dope is obtained;

S2. After filtering and defoaming the spinning dope, a spinning nozzle with an inner diameter of 1.0 mm is input through a metering pump, and the spinning dope is squeezed into a coagulation bath by a pressure of 100 N to obtain a chitosan monofilament; wherein, each group of the coagulation bath The mass percentage of the fraction includes: 5% sodium hydroxide, 3% ethanol, and the rest is deionized water;

S11, in a solid-liquid ratio of 10:100g / ml ratio, the salmon cartilage β-chitin is dissolved in a mass percentage concentration of 38% NaOH solution, stirred at 60 ° C for 5h and filtered to obtain filter residue;

The surgical suture prepared in this example has a diameter of 0.44 mm, a tensile strength of 45.41 N, and a tensile elongation at break of 14.19%.

Embodiment 4:

S1, 1.8g squid cartilage chitosan (DD=80.00%, MW=1.52×10 ⁶ ) powder was dissolved in 50ml, 2% by mass concentration of acetic acid solution, stirred under the action of magnetic stirrer for 2h, to be completely After dissolution, a spinning dope is obtained;

S2. After filtering and defoaming the spinning dope, a spinneret having an inner diameter of 0.8 mm is input through a metering pump, and the spinning dope is extruded into a coagulation bath by a pressure of 80 N to obtain a chitosan monofilament; wherein the coagulation bath groups are The mass percentage of the fraction includes: 4% sodium hydroxide, 2% ethanol, and the rest is deionized water;

S11, in a solid-liquid ratio of 15:100g / ml ratio, the salmon cartilage β-chitin is dissolved in a 40% by mass concentration of NaOH solution, stirred at 70 ° C for 3h and filtered to obtain filter residue;

The surgical suture prepared in this example has a diameter of 0.36 mm, a tensile strength of 45.06 N, and a tensile elongation at break of 14.10%.

Embodiment 5:

S1, 1.5g of squid cartilage chitosan (DD=80.12%, MW=1.2×10 ⁶ ) powder was dissolved in 50ml, 2% by mass concentration of acetic acid solution, stirred under the action of magnetic stirrer for 2h, to be completely After dissolution, a spinning dope is obtained;

S2. After filtering and defoaming the spinning dope, a spinning nozzle with an inner diameter of 0.8 mm is input through a metering pump, and the spinning dope is squeezed into a coagulation bath by a pressure of 20 N to obtain a chitosan monofilament; wherein, each group of the coagulation bath The mass percentage of the fraction includes: 4% sodium hydroxide, 2% ethanol, and the rest is deionized water;

S11. The squid cartilage chitosan (DD=80.00%, Mw=1.52×10 ⁶ ) powder prepared in Example 4 was dissolved at a mass concentration of 1 at a ratio of solid to liquid ratio of 15:100 g/ml. % hydrochloric acid solution, placed in an ultrasonic cleaner at 60 ° C for 2.5 h;

S12, adding 1mol/L NaOH solution to adjust the solution to neutrality, suction filtration, and the filter residue obtained by suction filtration is repeatedly washed with deionized water and absolute ethanol, and dried and ground in a blast drying oven at 60 °C. The squid cartilage chitosan powder was obtained.

The surgical suture prepared in this example has a diameter of 0.22 mm, a tensile strength of 44.98 N, and a tensile elongation at break of 14.12%.

Example 6:

S1, 2.0g of squid cartilage chitosan (DD=79.51%, MW=0.91×10 ⁶ ) powder was dissolved in 50ml, 2% by mass concentration of acetic acid solution, stirred under the action of magnetic stirrer for 2h, to be completely After dissolution, a spinning dope is obtained;

S2. After filtering and defoaming the spinning dope, a spinning nozzle with an inner diameter of 0.5 mm is input through a metering pump, and the spinning dope is extruded into a coagulation bath with a pressure of 50 N to obtain a chitosan monofilament; wherein, each group of the coagulation bath The mass percentage of the fraction includes: 4% sodium hydroxide, 2% ethanol, and the rest is deionized water;

S11, the squid cartilage chitosan (DD=80.00%, Mw=1.52×10 ⁶ ) powder prepared in Example 4 was dissolved at a mass concentration of 5 at a ratio of solid to liquid ratio of 10:100 g/ml. % hydrochloric acid solution, placed in an ultrasonic cleaner at 80 ° C for 4 h;

S12, adding 0.8 mol / L NaOH solution to adjust the solution to neutral, suction filtration, the filter residue obtained after suction filtration is repeatedly washed with deionized water and absolute ethanol, and placed in a blast drying oven at 60 ° C, Grinding to obtain a salmon cartilage chitosan powder.

The surgical suture prepared in this example has a diameter of 0.24 mm, a tensile strength of 45.21 N, and a tensile elongation at break of 14.02%.

Example 7:

S1, 2.5g salmon cartilage chitosan (DD=78.71%, MW=0.62×10 ⁶ ) powder was dissolved in 50ml, 2% by mass concentration of acetic acid solution, stirred under the action of magnetic stirrer for 2h, to be completely After dissolution, a spinning dope is obtained;

S2. After filtering and defoaming the spinning dope, a spinning nozzle with an inner diameter of 0.3 mm is input through a metering pump, and the spinning dope is squeezed into a coagulation bath by a pressure of 70 N to obtain a chitosan monofilament; wherein, each group of the coagulation bath The mass percentage of the fraction includes: 4% sodium hydroxide, 2% ethanol, and the rest is deionized water;

S3, chitosan monofilament is washed with deionized water to neutrality, and then stretched 10N at room temperature and dried 1 Days, the new chitosan absorbs surgical suture monofilaments.

S11, the squid cartilage chitosan (DD=80.00%, Mw=1.52×10 ⁶ ) powder prepared in Example 4 was dissolved in a mass percentage at room temperature according to a ratio of solid to liquid ratio of 15:100 g/ml. In a 3% hydrochloric acid solution, placed in an ultrasonic cleaner at 70 ° C for 8 h;

S12, adding 0.3 mol / L NaOH solution to adjust the solution to neutral, suction filtration, the filter residue obtained after suction filtration is repeatedly washed with deionized water and absolute ethanol, and placed in a blast drying oven at 60 ° C, Grinding to obtain a salmon cartilage chitosan powder.

The surgical suture prepared in this example has a diameter of 0.21 mm, a tensile strength of 45.38 N, and a tensile elongation at break of 14.09%.

Those skilled in the art will recognize that many variations are possible in the above description, and thus the embodiments are only used to describe one or more specific embodiments.

While the invention has been described and described with reference to the embodiments of the embodiments In addition, many modifications may be made to adapt a particular situation to the teachings of the invention, without departing from the inventive concept. Therefore, the invention is not limited to the specific embodiments disclosed herein, but the invention may also include all embodiments and equivalents thereof.

Claims

A method for preparing an absorbable surgical suture, comprising the steps of:

S1, the squid cartilage chitosan is dissolved to obtain a spinning dope; wherein the squid cartilage chitosan has a degree of deacetylation greater than 60% and a molecular weight greater than 0.5×10 6 ;

S2, drying the spinning dope and drying to obtain the absorbable surgical suture.
A method of preparing an absorbable surgical suture according to claim 1, wherein said spinning in step S2 is wet spinning.
The method for preparing an absorbable surgical suture according to claim 2, wherein the wet spinning comprises the steps of: feeding the spinning dope into a spinneret having an inner diameter of 0.1 to 1.0 mm through a metering pump; Pressing the spinning dope into a coagulation bath with a pressing force of 10 to 100 N to obtain a chitosan monofilament;

Wherein, the components of the coagulation bath comprise, by mass percentage, 4% to 6% of sodium hydroxide, 1% to 3% of ethanol, and the rest are deionized water.
The method for preparing an absorbable surgical suture according to claim 1, wherein in step S1, the squid cartilage chitosan is dissolved in a solvent at a ratio of solid to liquid of 1.0:100 to 5.0:100 g/ml. The spinning dope is obtained.
The method of preparing an absorbable surgical suture according to claim 4, wherein the solvent is acetic acid having a mass percent concentration of 2%.
The method for preparing an absorbable surgical suture according to claim 1, wherein the spinning dope further comprises filtering and defoaming the spinning dope before spinning the spinning dope in step S2.
The method for preparing an absorbable surgical suture according to claim 1, wherein the preparation of the salmon cartilage chitosan in step S1 comprises the following steps:

S11. The squid cartilage β-chitin is dissolved in a NaOH solution having a mass percentage concentration of 30% to 40% at a ratio of solid to liquid of 5.0:100 to 25:100 g/ml, and stirred at 50 to 80 ° C for 1 to 6 hours. After filtration, the first filter residue is obtained;

S12. The first filter residue is washed to neutral and then dried to obtain a first salmon cartilage chitosan as the salmon cartilage chitosan of step S1.
The method for preparing an absorbable surgical suture according to claim 7, further comprising the following steps after step S12:

S13. The first salmon cartilage chitosan obtained in step S12 is used as a first intermediate product, and is solidified. The first intermediate product is dissolved in a NaOH solution having a mass percentage concentration of 30% to 40% at a liquid ratio of 5.0:100 to 25:100 g/ml, and stirred at 50 to 80 ° C for 1 to 6 hours, followed by filtration. Second filter residue;

S14. The second filter residue is washed to neutrality and then dried to obtain a second salmon cartilage chitosan having a different degree of deacetylation from the first intermediate product as the salmon cartilage chitosan of step S1.
The method for preparing an absorbable surgical suture according to claim 7 or 8, further comprising the following steps after step S12 or step S14:

S15, the first squid cartilage chitosan obtained in step S12 or the second squid cartilage chitosan obtained in step S14 is used as a second intermediate product at a solid-liquid ratio of 5.0:100 to 25:100 g/ml. Proportion, the second intermediate product is dissolved in a hydrochloric acid solution having a mass percentage concentration of 1% to 5% at room temperature, and sonicated at 60 to 80 ° C for 2 to 8 hours to obtain a mixed solution;

S16, adding 0.1~1.0 mol/L NaOH solution to the mixture to adjust the mixture to neutrality, and suction filtration to obtain a third filter residue;

S17. The third filter residue is washed to neutrality and then dried to obtain a third salmon cartilage chitosan having a molecular weight different from that of the second intermediate product, as the salmon cartilage chitosan of step S1.
An absorbable surgical suture, which is produced by the method for preparing an absorbable surgical suture according to any one of claims 1-9.