Medical absorbable collagen antibacterial suture line and preparation method thereof

Abstract

The invention provides a medical absorbable collagen antibacterial suture line and a preparation method thereof. The preparation method comprises the following steps: S1, sequentially carrying out pretreatment, homogenization, digestion, sterilization, salting-out and purification on animal skin to obtain collagen; s2, performing solution blending on collagen and a chitosan derivative to prepare a spinning solution; s3, performing wet spinning on the spinning solution to obtain a wire rod; and S4, crosslinking or weaving the wire rod to prepare the medical antibacterial suture line capable of absorbing collagen. The suture line is high in collagen purity, in a special fiber bundle shape, low in antigenicity, good in spinnability, smooth in surface, soft and smooth in line body and easy to knot, does not need to be soaked before being used, can reduce scar hyperplasia and avoid centipede-shaped suture traces during suture, has antibacterial and hemostatic functions, and is suitable for clinical application. A physical hemostasis barrier can be quickly generated in the suturing process, and an excellent suturing effect is achieved.

Description

Technical Field

[0001] This invention relates to the field of collagen suture technology, and in particular to a medical absorbable collagen antibacterial suture and its preparation method. Background Technology

[0002] Currently, the collagen sutures used clinically on the market are mainly divided into two types: catgut sutures and beaver tail sutures.

[0003] After viral inactivation, catgut undergoes a chrome tanning process. While this process can prolong the degradation period and increase the strength of the catgut, the trivalent chromium introduced during chrome tanning accelerates its conversion to hexavalent chromium in bodily fluids. Hexavalent chromium is carcinogenic, sensitizing, and organ toxic, posing a potentially high risk to human health. Furthermore, the glutaraldehyde crosslinking agent used is also classified as a Group 3 carcinogen. If residual glutaraldehyde is present during surgery, it can cause chemical burns to the wound and neurotoxicity.

[0004] Beaver tail sutures are made from tendons extracted from the tail of beavers, and are produced through processes such as soaking, dehydration, air drying, and polishing. However, they suffer from issues such as stiffness. Furthermore, both catgut sutures and beaver tail sutures require soaking before use, which not only makes knotting the sutures during surgery difficult but also increases the operation time and poses potential risks to patients.

[0005] In view of the above problems, this invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a medical absorbable collagen antibacterial suture and its preparation method. The suture has a smooth surface, is soft and easy to knot, does not require soaking before use, can reduce scar hyperplasia during suturing, and has antibacterial and hemostatic functions.

[0007] This invention provides a method for preparing medical absorbable collagen antibacterial sutures, comprising the following steps: S1: The animal skin is pretreated, homogenized, digested, sterilized, salted out, and purified in sequence to obtain collagen. S2: Collagen and chitosan derivatives are solution blended to prepare spinning solution; S3: Wet spinning is performed on the spinning solution to obtain wire; S4: Cross-linking or braiding the thread to produce a medical absorbable collagen antibacterial suture.

[0008] In step S1, there are no strict restrictions on the animal hides used; for example, fresh cowhide, pigskin, sheepskin, etc., can be used.

[0009] Pretreatment includes: removing dust, grease and adhering fascia from the animal skin, then soaking it in a 1-15 wt% acetic acid solution for 24-168 h, for example, a concentration of 10% acetic acid solution and a soaking time of 72 h; rinsing after soaking, removing hair and subcutaneous soft tissue, cleaning thoroughly, cutting into pieces and crushing.

[0010] Homogenization includes: placing the pretreated animal skin in a 0.2-1 mol / L acetic acid solution, stirring at room temperature for 5-10 h, then removing it and adding another 0.2-1 mol / L acetic acid solution for homogenization; during homogenization, the mass ratio of animal skin to acetic acid solution can be 1:(8-12), for example, 1:10.

[0011] Digestion includes: adding pepsin solution to the suspension obtained by homogenization, digesting at 15-25 °C for 2-8 days (e.g., 2-5 days), and then inactivating pepsin; specifically, the activity of the pepsin solution can be 0.02-0.5 U / mL, for example 0.05-0.2 U / mL, and the volume ratio of suspension to pepsin solution can be (20-80):1; inactivation includes: adjusting the pH of the digested solution to 8-10 with 5-10 mol / L NaOH solution to inactivate pepsin.

[0012] Salting out involves adding 1-2 mol / L (e.g., 1.4-1.6 mol / L) sodium chloride solution to the sterilized solution obtained from sterilization, allowing it to stand for 20-30 h, then centrifuging and collecting the lower precipitate. Specifically, the volume ratio of the sterilized solution to the sodium chloride solution can be 1:(0.8-1.2), for example, 1:1. The centrifugation speed can be 11000-13000 r / min, and the centrifugation time can be 20-40 min.

[0013] Purification involves dissolving the precipitate obtained from salting out in a 0.4-0.6 mol / L acetic acid solution, dialyzing first with a 0.03-0.05 mol / L sodium dihydrogen phosphate solution for 20-30 h, then dialyzing with a 0.01-0.03 mol / L sodium dihydrogen phosphate solution for 20-30 h, followed by dialyzing with ultrapure water for 45-50 h. The concentration of the sodium dihydrogen phosphate solution used in the second dialysis is controlled to be 0.01-0.02 mol / L lower than that used in the first dialysis. Alternatively, ultrafiltration can be used for desalination.

[0014] Furthermore, the dialysis products can be freeze-dried after dialysis to obtain collagen freeze-dried powder, which can then be stored under cold conditions.

[0015] In step S2, the chitosan derivative can be carboxymethyl chitosan; the mass ratio of collagen to chitosan derivative in the spinning solution is controlled to be 1:(1-25).

[0016] More specifically, the solution blending includes: stirring and mixing a chitosan derivative solution and a collagen solution; wherein the chitosan derivative solution is prepared by mixing a chitosan derivative with a 1-3 wt% acetic acid solution, and the mass ratio of the chitosan derivative to the acetic acid solution can be 1:(10-12); the collagen solution is prepared by mixing collagen with a 0.4-0.6 mol / L acetic acid solution, and the mass ratio of the collagen to the acetic acid solution can be 1:(80-120).

[0017] In step S3, wet spinning includes: degassing, filtering, and spinning the spinning solution to form nascent fibers in a coagulation bath; the nascent fibers are sequentially drawn through a coagulation bath, a first drawing roller, a drawing bath, a washing bath, a second drawing roller, a setting box, a third drawing roller, and a winding machine to obtain wire; specifically, the coagulation bath uses a saturated sodium sulfate solution at a temperature of 35-40 ℃; the drawing bath uses a 40-60 wt% ethanol solution at a temperature of 40-50 ℃; the washing bath uses purified water at a temperature of 40-50 ℃; the setting box temperature is 80-100 ℃; the first drawing roller draws at 5-7 m / min, the second drawing roller draws at 16-18 m / min, and the third drawing roller draws at 19-21 m / min; the wire diameter is 0.1-0.7 mm, for example, 0.2-0.4 mm (3-0 specification wire diameter or 4-0 specification wire diameter).

[0018] In step S4, crosslinking includes: soaking the suture in a 0.3-0.5 wt% genipin solution for 2-4 hours (e.g., 2-3 hours), followed by rinsing with ultrapure water 2-5 times to remove free genipin, and then drying and shaping the suture; wherein the drying and shaping temperature can be 30-45 ℃, for example 40-45 ℃, and the drying and shaping time can be 6-24 hours, for example 8-18 hours. Genipin is a natural green crosslinking agent derived from geniposide, which has excellent biocompatibility and antibacterial properties, can reduce tissue inflammation, and lower the risk of postoperative infection; the epoxide of genipin undergoes ring-opening and crosslinks with the amino groups of carboxymethyl chitosan and collagen to form a stable three-dimensional network structure, and the ester group of genipin can also undergo condensation reaction with the carboxyl groups of both, making it a suitable and ideal crosslinking agent for absorbable collagen sutures in this invention.

[0019] The present invention also provides a medical absorbable collagen antibacterial suture, which is prepared according to the above preparation method.

[0020] The implementation of this invention has at least the following advantages: 1. The collagen extracted by this invention has high purity, low antigenicity, and high process safety. It is freeze-dried into collagen freeze-dried powder, which is easy to store.

[0021] 2. The suture prepared by this invention has a smooth surface and is easy to knot; at the same time, the suture is soft and does not need to be soaked before use, which helps to shorten the operation time.

[0022] 3. The collagen in the suture matrix of the present invention can reduce scar hyperplasia and avoid "centipede-like" suture marks. The chitosan derivative not only has antibacterial function, but also hemostatic function. It can quickly generate a physical hemostatic barrier during the suturing process and has excellent suturing effect. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 Electron micrograph of the collagen prepared in Example 1; Figure 2 The image shows the antibacterial effect of the spinning solution prepared in Example 1. Figure 3 Cell liveness and death staining fluorescence image of the medical absorbable collagen antibacterial suture prepared in Example 1; Figure 4 The cell viability results for the medical absorbable collagen antibacterial suture prepared in Example 1; Figure 5 Optical density results for the medical absorbable collagen antibacterial suture prepared in Example 1; Figure 6 The force-deformation curve of the medical absorbable collagen antibacterial suture prepared in Example 1; Figure 7 The force-deformation curve of the medical absorbable collagen antibacterial suture prepared in Example 2; Figure 8 The force-deformation curve of the medical absorbable collagen antibacterial suture prepared in Example 3; Figure 9 Electrophoresis image of the medical absorbable collagen antibacterial suture prepared in Example 3; Figure 10 The force-deformation curve of the medical absorbable collagen antibacterial suture prepared in Example 4; Figure 11 Electrophoresis diagram of absorbable collagen surgical sutures, as shown in Example 1. Detailed Implementation

[0025] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1 The preparation method of the medical absorbable collagen antibacterial suture in this embodiment includes the following steps: Step 1: Preparation of collagen freeze-dried powder 1.1 Pre-treatment of cowhide After removing dust from the fresh cowhide, scrape off the grease and adhering fascia with a knife. Soak the treated cowhide in a 10% glacial acetic acid solution for 72 hours. After soaking, remove the cowhide, rinse it clean, scrape off the hair and soft subcutaneous tissue with a knife, clean it thoroughly, and cut it into 5 cm × 5 cm pieces. Grind the pieces of cowhide with a meat grinder.

[0029] 1.2 Homogenization and Digestion The cowhide pretreated in step 1.1 was swollen with 0.2 mol / L acetic acid solution and stirred at room temperature for 10 h. The waste liquid was discarded, and then 0.2 mol / L acetic acid solution was added again, controlling the mass ratio of cowhide to acetic acid solution to 1:10. Homogenization was performed using a homogenizer to obtain a suspension.

[0030] A pepsin solution with an activity of 0.2 U / mL was transferred into the above suspension for digestion, and the volume ratio of the suspension to the pepsin solution was controlled at 80:1. Digestion was carried out at 15 °C for 5 days, and then the pH of the digestion solution was adjusted to 10 using 10 mol / L NaOH solution to inactivate the pepsin.

[0031] 1.3 Sterilization and salt precipitation centrifugation Connect the sterile filter to a bottle containing 10 mmol / L hydrochloric acid solution, a peristaltic pump, and an empty bottle. First, remove the air, then wet the filter element. After wetting, sterilize the digestion solution obtained in step 1.2 and collect the liquid to obtain the sterile solution.

[0032] Add 1.5 mol / L sodium chloride solution to the above sterilization solution for salting out, controlling the volume ratio of sterilization solution to sodium chloride solution to be 1:1. After standing for 24 h, centrifuge the collagen solution after salting out at 12000 r / min for 30 min and collect the lower precipitate.

[0033] 1.4 Dialysis Lyophilization The precipitate obtained in step 1.3 was redissolved in 0.5 mol / L acetic acid solution, dialyzed with 0.04 mol / L sodium dihydrogen phosphate solution for 24 h, then dialyzed with 0.02 mmol / L sodium dihydrogen phosphate solution in a gradient for 24 h, and then dialyzed with ultrapure water for 48 h. Dialysis was performed using dialysis bags from Ruida Heng Hui Technology, with a diameter of 34 mm and a molecular weight cutoff of 5 kDa. After dialysis, the dialysis product was freeze-dried using a SCIENTZ-30F / B freeze dryer to obtain collagen freeze-dried powder, which was then stored under cold storage.

[0034] Electron micrograph of the prepared collagen is shown in the figure. Figure 1 The results showed that, unlike conventional emulsified liquid collagen, the collagen prepared by this invention is in the form of special fiber bundles with a D-periodic striation spacing of about 65 nm visible on the fiber bundles. It has excellent spinnability and can form intermolecular blends with carboxymethyl chitosan for spinning, thereby improving the strength and suturing effect of the suture.

[0035] Step 2: Preparation of spinning solution 2.1 Preparation of carboxymethyl chitosan solution 10 g of carboxymethyl chitosan conforming to the requirements of the Pharmacopoeia of the People's Republic of China was selected and 110 g of 2 wt% acetic acid was added. The mixture was stirred at 40 °C for 2 h until a transparent liquid was obtained, thus preparing a carboxymethyl chitosan solution.

[0036] 2.2 Preparation of collagen solution Take 10 g of the lyophilized collagen powder obtained in step 1, and redissolve it with 30 g of 0.5 mol / L acetic acid solution. Stir until a transparent liquid is obtained to prepare a collagen solution.

[0037] 2.3 Solution blending The collagen solution from step 2.2 was poured into the carboxymethyl chitosan solution from step 2.1, with a mass ratio of collagen to carboxymethyl chitosan of 1:1. The mixture was stirred at 40 °C for 1 h to obtain the spinning solution.

[0038] The antibacterial effect of the spinning solution against *Escherichia coli* and *Staphylococcus aureus* was determined using the plate count method. The results are shown in [Figure number missing]. Figure 2 Meanwhile, the antibacterial rate is calculated using the following formula:

[0039] The results showed that the number of colonies in the Escherichia coli test group (a) was 5 CFU, and the number of colonies in the control group (b) was 200 CFU, with an antibacterial rate of 97.5%; the number of colonies in the Staphylococcus aureus test group (c) was 5 CFU, and the number of colonies in the control group (d) was 250 CFU, with an antibacterial rate of 98%.

[0040] Step 3: Wet spinning to prepare wire The spinning solution prepared in step 2 is placed in the solution tank of the wet spinning machine. After settling and vacuuming, air bubbles are removed from the spinning solution. The deaerated spinning solution is then delivered to the metering pump via external compressed air. The metered spinning solution is filtered through the spinneret filter and then sent to the spinneret assembly through the solution pipeline. The spinning solution passes through the distribution plate and spinneret inside the assembly to obtain a fine flow of solution.

[0041] In this embodiment, a single-hole spinneret is used to prepare monofilament wire. The wire is sequentially drawn through a coagulation bath, a first drawing roller, a drawing bath, a washing bath, a second drawing roller, a setting box, a third drawing roller, and a winding machine. The coagulation bath uses a saturated sodium sulfate solution at a temperature of 40 ℃, the drawing bath uses a 50 wt% ethanol solution at a temperature of 45 ℃, the washing bath uses purified water at a temperature of 45 ℃, the setting box temperature is 90 ℃, the first drawing roller draws at 6 m / min, the second drawing roller draws at 17 m / min, and the third drawing roller draws at 20 m / min.

[0042] The wire on the winding spool was taken and its diameter was tested according to the standard "YY1116-2020 Absorbable Surgical Sutures". The results showed that the wire diameter was 0.225 mm, which is in line with the 4-0 specification wire diameter (0.200-0.249 mm) in the standard.

[0043] Step 4: Monofilament suture process Genipin that meets the pharmacopoeia requirements was selected and added to ultrapure water to prepare a genipin solution with a concentration of 0.3 wt%. The temperature of the genipin solution was controlled at a constant 30 ℃.

[0044] The monofilament prepared in step 3 was immersed in the above genipin solution for 3 hours. After immersion, the monofilament was removed and rinsed three times with ultrapure water to remove free genipin. Then, the monofilament was dried and shaped at 40 °C for 18 hours to obtain medical absorbable collagen antibacterial suture.

[0045] Using L929 cells as a model, the cytotoxicity of medical absorbable collagen antibacterial sutures was evaluated using an extract culture method. The experiment included a control group (C), group A (medical absorbable collagen antibacterial sutures, A), and group B (Johnson & Johnson absorbable sutures, B). Cell viability (CV) and optical density (OD) values ​​were measured at different time points (day 1, day 3, and day 5), and cell viability and death were stained and photographed. Results are shown below. Figure 3 The results showed that each group had a large number of live cells with normal morphology and a very low percentage of dead cells, further verifying the biocompatibility of the material and providing biosafety support for clinical applications.

[0046] Cell viability (CV) and optical density (OD) results are shown in the figure. Figure 4 , Figure 5 The results showed that the cell survival rate of each group remained above 90% at all three time points, indicating that the extracts of each material did not severely inhibit cell survival, the experimental system had good stability, and the overall system met the basic requirements for low cytotoxicity of medical materials. In addition, the OD values ​​of each group showed a significant upward trend with the extension of culture time, which is consistent with the time-dependent law of cell growth, indicating that the material did not inhibit cell proliferation, and the extract of the material may have a promoting effect on cell proliferation or metabolic activity.

[0047] The breaking strength was tested according to the standard YY1116-2020 Absorbable Surgical Sutures, and the results are shown below. Figure 6 The results show that the fracture strength is 9.16 N, which meets the standard (≥7.55 N).

[0048] Example 2 The preparation method of the medical absorbable collagen antibacterial suture in this embodiment includes the following steps: Step 1: Preparation of collagen freeze-dried powder 1.1 Processing cowhide After removing dust from the fresh cowhide, scrape off the grease and adhering fascia with a knife. Soak the treated cowhide in a 10% glacial acetic acid solution for 72 hours. After soaking, remove the cowhide, rinse it clean, scrape off the hair and soft subcutaneous tissue with a knife, clean it thoroughly, and cut it into 2 cm × 2 cm pieces. Grind the pieces of cowhide with a meat grinder.

[0049] 1.2 Homogenization and Digestion The cowhide pretreated in step 1.1 was swollen with a 1 mol / L acetic acid solution and stirred at room temperature for 5 h. The waste liquid was then discarded, and another 1 mol / L acetic acid solution was added. The mass ratio of cowhide to acetic acid solution was controlled at 1:10. Homogenization was performed using a homogenizer to obtain a suspension.

[0050] A pepsin solution with an activity of 0.05 U / mL was transferred into the above suspension for digestion, and the volume ratio of the suspension to the pepsin solution was controlled at 20:1. Digestion was carried out at 25 °C for 2 days. Then, the pH of the digestion solution was adjusted to 8 using 5 mol / L NaOH solution to inactivate the pepsin.

[0051] 1.3 Sterilization and salt precipitation centrifugation Connect the sterile filter to a bottle containing 10 mmol / L hydrochloric acid solution, a peristaltic pump, and an empty bottle. First, remove the air, then wet the filter element. After wetting, sterilize the digestion solution obtained in step 1.2 and collect the liquid to obtain the sterile solution.

[0052] Add 1.4 mol / L sodium chloride solution to the above sterilization solution for salting out, controlling the volume ratio of sterilization solution to sodium chloride solution to be 1:1. After standing for 30 h, centrifuge the collagen solution after salting out at 12000 r / min for 30 min and collect the lower precipitate.

[0053] 1.4 Dialysis Lyophilization The precipitate obtained in step 1.3 was redissolved in 0.4 mol / L acetic acid solution, dialyzed with 0.03 mol / L sodium dihydrogen phosphate solution for 20 h, then dialyzed with 0.01 mol / L sodium dihydrogen phosphate solution in a gradient for 20 h, and then dialyzed with ultrapure water for 45 h. Dialysis was performed using dialysis bags from Ruida Heng Hui Technology, with a diameter of 34 mm and a molecular weight cutoff of 5 kDa. After dialysis, the dialysis product was freeze-dried using a SCIENTZ-30F / B freeze dryer to obtain collagen freeze-dried powder, which was then stored under cold storage.

[0054] Step 2: Preparation of spinning solution 2.1 Preparation of carboxymethyl chitosan solution 10 g of carboxymethyl chitosan conforming to the requirements of the Pharmacopoeia of the People's Republic of China was selected and 110 g of 2 wt% acetic acid was added. The mixture was stirred at 40 °C for 2 h until a transparent liquid was obtained, thus preparing a carboxymethyl chitosan solution.

[0055] 2.2 Preparation of collagen solution Take 1 g of the lyophilized collagen powder obtained in step 1, and redissolve it with 30 g of 0.5 mol / L acetic acid solution. Stir until a transparent liquid is obtained to prepare a collagen solution.

[0056] 2.3 Solution blending The collagen solution from step 2.2 was poured into the carboxymethyl chitosan solution from step 2.1, with a mass ratio of collagen to carboxymethyl chitosan of 1:10. The mixture was stirred at 40 °C for 1 h to obtain the spinning solution.

[0057] Step 3: Wet spinning to prepare wire The spinning solution prepared in step 2 is placed in the solution tank of the wet spinning machine. After settling and vacuuming, air bubbles are removed from the spinning solution. The deaerated spinning solution is then delivered to the metering pump via external compressed air. The metered spinning solution is filtered through the spinneret filter and then sent to the spinneret assembly through the solution pipeline. The spinning solution passes through the distribution plate and spinneret inside the assembly to obtain a fine flow of solution.

[0058] In this embodiment, a single-hole spinneret is used to prepare monofilament wire. The wire is sequentially drawn through a coagulation bath, a first drawing roller, a drawing bath, a washing bath, a second drawing roller, a setting box, a third drawing roller, and a winding machine. The coagulation bath uses a saturated sodium sulfate solution at a temperature of 35 ℃, the drawing bath uses a 40 wt% ethanol solution at a temperature of 40 ℃, the washing bath uses purified water at a temperature of 40 ℃, and the setting box temperature is 80 ℃. The drawing speed of the first drawing roller is 6 m / min, the second drawing roller is 17 m / min, and the third drawing roller is 20 m / min.

[0059] Take the suture from the winding spool and test the suture diameter according to the standard "YY1116-2020 Absorbable Surgical Sutures"; the results show that the suture diameter is 0.322 mm, which meets the 3-0 specification suture diameter (0.300-0.349 mm) in the standard.

[0060] Step 4: Monofilament suture process Genipin that meets the pharmacopoeia requirements was selected and added to ultrapure water to prepare a genipin solution with a concentration of 0.5 wt%. The temperature of the genipin solution was controlled at a constant 30 ℃.

[0061] The monofilament prepared in step 3 was immersed in the above genipin solution for 2 hours. After immersion, the monofilament was removed and rinsed 5 times with ultrapure water to remove free genipin. Then, the monofilament was dried and shaped at 45 °C for 8 hours to obtain medical absorbable collagen antibacterial suture.

[0062] The breaking strength was tested according to the standard YY1116-2020 Absorbable Surgical Sutures, and the results are shown below. Figure 7 The results show that the fracture strength is 14.17 N, which meets the standard (≥12.2 N).

[0063] Example 3 The preparation method of the medical absorbable collagen antibacterial suture in this embodiment includes the following steps: Step 1: Preparation of collagen freeze-dried powder 1.1 Processing cowhide After removing dust from the fresh cowhide, scrape off the grease and adhering fascia with a knife. Soak the treated cowhide in a 10% glacial acetic acid solution for 72 hours. After soaking, remove the cowhide, rinse it clean, scrape off the hair and soft subcutaneous tissue with a knife, clean it thoroughly, and cut it into 4 cm × 4 cm pieces. Grind the pieces of cowhide with a meat grinder.

[0064] 1.2 Homogenization and Digestion The cowhide pretreated in step 1.1 was swollen with 0.5 mol / L acetic acid solution and stirred at room temperature for 8 h. The waste liquid was discarded, and then another 0.5 mol / L acetic acid solution was added, controlling the mass ratio of cowhide to acetic acid solution to 1:10. Homogenization was performed using a homogenizer to obtain a suspension.

[0065] A pepsin solution with an activity of 0.1 U / mL was transferred into the above suspension for digestion, and the volume ratio of the suspension to the pepsin solution was controlled at 30:1. Digestion was carried out at 20 °C for 4 days, and then the pH of the digestion solution was adjusted to 9 with 10 mol / L NaOH solution to inactivate the pepsin.

[0066] 1.3 Sterilization and salt precipitation centrifugation Connect the sterile filter to a bottle containing 10 mmol / L hydrochloric acid solution, a peristaltic pump, and an empty bottle. First, remove the air, then wet the filter element. After wetting, sterilize the digestion solution obtained in step 1.2 and collect the liquid to obtain the sterile solution.

[0067] Add 1.6 mol / L sodium chloride solution to the above sterilization solution for salting out, controlling the volume ratio of sterilization solution to sodium chloride solution to be 1:1. After standing for 30 h, centrifuge the collagen solution after salting out at 12000 r / min for 30 min and collect the lower precipitate.

[0068] 1.4 Dialysis Lyophilization The precipitate obtained in step 1.3 was redissolved in 0.6 mol / L acetic acid solution, dialyzed against 0.05 mol / L sodium dihydrogen phosphate solution for 30 h, then dialyzed against 0.03 mol / L sodium dihydrogen phosphate solution in a gradient for 30 h, and finally dialyzed against ultrapure water for 50 h. Dialysis was performed using dialysis bags from Ruida Heng Hui Technology, with a diameter of 34 mm and a molecular weight cutoff of 5 kDa. After dialysis, the dialysis product was freeze-dried using a SCIENTZ-30F / B freeze dryer to obtain collagen freeze-dried powder, which was then stored under cold storage.

[0069] Step 2: Preparation of spinning solution 2.1 Preparation of carboxymethyl chitosan solution 10 g of carboxymethyl chitosan conforming to the requirements of the Pharmacopoeia of the People's Republic of China was selected and 110 g of 2 wt% acetic acid was added. The mixture was stirred at 40 °C for 2 h until a transparent liquid was obtained, thus preparing a carboxymethyl chitosan solution.

[0070] 2.2 Preparation of collagen solution Select 0.4 g of the lyophilized collagen powder obtained in step 1, and redissolve it with 30 g of 0.5 mol / L acetic acid solution. Stir until a transparent liquid is obtained to prepare a collagen solution.

[0071] 2.3 Solution blending The collagen solution from step 2.2 was poured into the carboxymethyl chitosan solution from step 2.1, with a mass ratio of collagen to carboxymethyl chitosan of 1:25. The mixture was stirred at 40 °C for 1 h to obtain the spinning solution.

[0072] Step 3: Wet spinning to prepare wire The spinning solution prepared in step 2 is placed in the solution tank of the wet spinning machine. After settling and vacuuming, air bubbles are removed from the spinning solution. The deaerated spinning solution is then delivered to the metering pump via external compressed air. The metered spinning solution is filtered through the spinneret filter and then sent to the spinneret assembly through the solution pipeline. The spinning solution passes through the distribution plate and spinneret inside the assembly to obtain a fine flow of solution.

[0073] In this embodiment, a single-hole spinneret is used to prepare multifilament yarn. The yarn is sequentially drawn through a coagulation bath, a first drafting roller, a drafting bath, a washing bath, a second drafting roller, a setting box, a third drafting roller, and a winding machine. The coagulation bath uses a saturated sodium sulfate solution at a temperature of 40 ℃, the drafting bath uses a 60 wt% ethanol solution at a temperature of 50 ℃, the washing bath uses purified water at a temperature of 50 ℃, and the setting box temperature is 100 ℃. The drafting speed of the first drafting roller is 6 m / min, the drafting speed of the second drafting roller is 17 m / min, and the drafting speed of the third drafting roller is 20 m / min.

[0074] Take the wire from the winding spool and measure its linear density using a YG086 yarn length measuring machine; it is 52 dtex.

[0075] Step 4: Multifilament braided stitching process The thread prepared in step 3 is twisted and then wound into 16 spools with a twist of 60 turns per meter. The thread is then braided using a KBL16-90 16-spindle braiding machine at a spindle speed of 85 r / min and a braiding pitch of 3.1 mm to ensure that the thread is tightly interwoven and stress is dispersed, thus producing a medical absorbable collagen antibacterial suture.

[0076] The suture diameter and breaking strength were tested according to the standard YY1116-2020 Absorbable Surgical Sutures. The results showed that the suture diameter was 0.387 mm, which conforms to the 2-0 specification suture diameter (0.350-0.399 mm) in the standard; the breaking strength was 22.69 N (see [reference needed]). Figure 8 It meets the standard (≥19.6 N).

[0077] Samples were taken for electrophoresis testing. Lane 1 contained molecular weight standards (markers), and lane 2 contained suture samples. Results are shown below. Figure 9 The results showed that the collagen purity was 100%.

[0078] Example 4 Except for step 1.4, the rest is the same as in Example 1; in this example, step 1.4 uses ultrafiltration lyophilization, as detailed below: The precipitate obtained in step 1.3 was redissolved in a 0.5 mol / L acetic acid solution, and the collagen was desalted and purified using an ultrafiltration system, as follows: Membrane pretreatment: Place the inlet and reflux tubes into 30 L of 0.1 mol / L sodium hydroxide solution. Place the permeate end tubing into a floor drain. Turn on the ultrafiltration system and drain 15 L of 0.1 mol / L sodium hydroxide solution. Then close the permeate end tubing. The total circulation time should be at least 30 min. Open the permeate end tubing and drain the sodium hydroxide solution in the tubing. Then place the inlet tube into 40 L of purified water. Connect the reflux end and the permeate end to a floor drain for rinsing. Then equilibrate the membrane with at least 15 L of 10 mmol / L hydrochloric acid solution. Use test strips to check that the pH value of the reflux outlet and the permeate end is neutral.

[0079] Start the peristaltic pump for circulation concentration at a speed of 450 r / min. Pump the collagen solution into the ultrafiltration system and concentrate it at a pressure of 0.15 MPa until the volume is reduced to 1 / 6 of the original volume.

[0080] Finally, the dialysis products were freeze-dried using a SCIENTZ-30F / B freeze dryer to obtain collagen freeze-dried powder, which was then refrigerated.

[0081] The breaking strength was tested according to the standard YY1116-2020 Absorbable Surgical Sutures, and the results are shown below. Figure 10 The results show that the fracture strength is 9.22 N, which meets the standard (≥7.55 N).

[0082] Compare with Example 1 A commercially available brand of absorbable collagen surgical sutures, specification 3-0, was selected. Samples were taken for electrophoresis testing; lane 1 was used for molecular weight standards (markers), and lane 2 was used for the surgical suture samples. Results are shown below. Figure 11 The results showed that the surgical sutures were not clearly defined and contained miscellaneous sutures.

[0083] Compare with Example 2 Except for replacing the carboxymethyl chitosan in Example 1 with chitosan, the rest is the same as in Example 1.

[0084] Compare with Example 3 Except for replacing the carboxymethyl chitosan in Example 1 with polycaprolactone, the rest is the same as in Example 1.

[0085] Compare with Example 4 Except for replacing the cowhide in Example 1 with pig Achilles tendon, the rest is the same as in Example 1.

[0086] Smoothness was tested using the ASTM F2382-19 drag force method, and breaking strength was tested using the YY1116-2020 absorbable surgical suture standard. Flexibility was verified using the measured elastic modulus. The results are shown in Table 1.

[0087] Table 1

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a medical absorbable collagen antibacterial suture, characterized in that, Includes the following steps: S1: The animal skin is pretreated, homogenized, digested, sterilized, salted out, and purified in sequence to obtain collagen. S2: Collagen and chitosan derivatives are solution blended to prepare spinning solution; S3: Wet spinning is performed on the spinning solution to obtain wire; S4: Cross-linking or braiding the thread to produce a medical absorbable collagen antibacterial suture.

2. The preparation method according to claim 1, characterized in that, Pretreatment includes: removing dust, grease and adhering fascia from the animal skin, soaking in a 1-15 wt% acetic acid solution for 24-168 h; rinsing after soaking, removing hair and soft subcutaneous tissue, cleaning thoroughly, cutting into pieces and crushing.

3. The preparation method according to claim 1, characterized in that, Homogenization involves placing the pretreated animal skin in a 0.2-1 mol / L acetic acid solution, stirring at room temperature for 5-10 h, then removing it and adding another 0.2-1 mol / L acetic acid solution for homogenization.

4. The preparation method according to claim 1, characterized in that, Digestion includes: Add pepsin solution to the suspension obtained by homogenization and digest at 15-25 °C for 2-8 days, then inactivate pepsin.

5. The preparation method according to claim 1, characterized in that, Salting out includes: Add 1-2 mol / L sodium chloride solution to the sterilized solution obtained by sterilization, let it stand for 20-30 h, then centrifuge and collect the lower precipitate.

6. The preparation method according to claim 5, characterized in that, Purification includes: The precipitate obtained by salting out was dissolved in 0.4-0.6 mol / L acetic acid solution. Dialysis was first performed with 0.03-0.05 mol / L sodium dihydrogen phosphate solution for 20-30 h, then with 0.01-0.03 mol / L sodium dihydrogen phosphate solution for 20-30 h, and finally with ultrapure water for 45-50 h. The concentration of sodium dihydrogen phosphate solution used in the second dialysis was controlled to be 0.01-0.02 mol / L lower than that used in the first dialysis.

7. The preparation method according to claim 1, characterized in that, The mass ratio of collagen to chitosan derivative in the spinning solution is controlled to be 1:(1-25).

8. The preparation method according to claim 1, characterized in that, The wire diameter is 0.1-0.7 mm.

9. The preparation method according to claim 1, characterized in that, Crosslinking includes: The wire is soaked in a 0.3-0.5 wt% genipin solution for 2-4 hours, then rinsed 2-5 times with ultrapure water to remove free genipin, and then dried and shaped.

10. A medical absorbable collagen antibacterial suture, characterized in that, Prepared according to the preparation method according to any one of claims 1-9.

Images