Polycitrate modified artificial ligament and preparation method thereof

Abstract

The invention provides a poly-citrate modified artificial ligament and a preparation method thereof, and belongs to the technical field of biomedical materials, and the poly-citrate modified artificial ligament is formed by rolling a poly-citrate coating modified PET woven film. According to the modified PET artificial ligament prepared from the PET woven film modified by the polycitrate coating, the biocompatibility and osteogenic activity of the PET artificial ligament are improved, the chronic foreign body reaction is improved, the mechanical behavior of natural ligament tissue can be better simulated, and the osseointegration capacity of the PET artificial ligament is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of biomedical materials and relates to a polycitrate-modified artificial ligament and a preparation method thereof. Background Art

[0002] At present, the incidence of anterior cruciate ligament injury caused by sports shows a clear upward trend. Anterior cruciate ligament reconstruction is the first choice for treating this injury, and the selection of grafts is the key to the success of the operation. The grafts commonly used in clinical anterior cruciate ligament reconstruction include autologous grafts, allogeneic grafts, and polyethylene terephthalate (PET) artificial ligaments. Due to the advantages of PET artificial ligaments such as sufficient supply, superior mechanical properties, and the ability to promote rapid recovery after surgery, they are widely used in anterior cruciate ligament reconstruction surgery. Through the analysis of adverse events after PET artificial ligament surgery, bone tunnel enlargement is a characteristic manifestation of failed cases, which may not only cause the graft to rupture again, but also increase the risk of surgical failure, thereby increasing the difficulty of revision surgery and the incidence of osteoarthritis. Therefore, how to effectively promote the good integration of PET artificial ligaments with bones is the main challenge faced in clinical anterior cruciate ligament reconstruction surgery.

[0003] When PET grafts are used to reconstruct the anterior cruciate ligament, the following problems exist: PET, as a non-degradable inert hydrophobic material, leads to insufficient interaction between it and cells, thus affecting biocompatibility; during the PET implantation process, friction between it and the tunnel bone tissue will produce friction particles, which are considered to be the main cause of chronic foreign body reaction (inflammation). This reaction may cause long-term pain and dysfunction; persistent chronic inflammatory response will activate fibroblasts, leading to excessive fibrosis at the implant interface, affecting the stability and function of the graft and increasing the risk of postoperative complications; chronic inflammatory response will also hinder the adhesion and regeneration of endothelial cells and hinder the process of angiogenesis. This not only delays the healing time, but may also lead to local blood supply insufficiency, thus affecting the biological integration and functional recovery of the PET graft. In summary, although PET artificial ligaments are widely used due to their superior mechanical properties, they still face many challenges and shortcomings in clinical use, and there is an urgent need to improve material design or surgical techniques to improve their clinical effects and postoperative recovery of patients.

[0004] Therefore, in the art, it is desired to develop a modified PET artificial ligament to improve the biocompatibility and osteogenic activity of the artificial ligament, improve chronic foreign body reaction, etc. Summary of the invention

[0005] In view of the deficiencies of the prior art, the object of the present invention is to provide a polycitrate-modified artificial ligament and a preparation method thereof for reconstruction of the anterior cruciate ligament.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a polycitrate-modified artificial ligament, wherein the polycitrate-modified artificial ligament is rolled from a PET woven film modified with a polycitrate coating.

[0007] The modified PET artificial ligament prepared from the PET woven film modified by the polycitrate coating of the present invention improves the biocompatibility and osteogenic activity of the PET artificial ligament, improves chronic foreign body reaction (inflammation), can better simulate the mechanical behavior of natural ligament tissue, and improves the bone integration ability of the PET artificial ligament.

[0008] In addition, the residual carboxyl and hydroxyl groups on the polycitrate coating can also be further functionally modified to enhance the application potential of the material.

[0009] Preferably, the polycitrate coating-modified PET woven film comprises a PET woven film and a polycitrate coating disposed on both side surfaces and in the gaps of the PET woven film.

[0010] Preferably, the polycitrate coating is obtained by curing a polycitrate prepolymer.

[0011] Preferably, the polycitrate prepolymer includes any one of poly(1,8-octanediol) citrate prepolymer, poly(ethylene glycol) citrate prepolymer, poly(glycerol) citrate prepolymer, poly(1,4-butylene glycol) citrate prepolymer, and poly(citrate-caprolactone) prepolymer, or a combination of at least two of them.

[0012] Preferably, the molecular weight of the polycitrate prepolymer is 1000-10000Da, for example 1000Da, 2000Da, 3000Da, 4000Da, 5000Da, 6000Da, 7000Da, 8000Da, 9000Da, 10000Da, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0013] Preferably, the polycitrate prepolymer is prepared by a melt reaction.

[0014] Preferably, the polycitrate prepolymer is prepared by the following method: The citric acid and the polyol are mixed and melt-reacted to obtain the polycitrate prepolymer, wherein the polyol includes any one of 1,8-octanediol, ethylene glycol, glycerol, 1,4-butanediol, and 6-hydroxyacetic acid, or a combination of at least two thereof.

[0015] Preferably, the molar ratio of citric acid to polyol is 1:(0.8-1.2), such as 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, etc., but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. By controlling the molar ratio of citric acid to polyol within a specific range, the properties of the obtained polycitrate prepolymer can be regulated, thereby regulating the mechanical properties, degradation properties and osteogenic activity of the polycitrate.

[0016] Preferably, the temperature of the melt reaction is 120-160°C, such as 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, etc., but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. The time of the melt reaction is 10-90min, such as 10min, 20min, 30min, 40min, 50min, 60min, 70min, 80min, 90min, etc., but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. The molecular weight of the polycitrate prepolymer can be regulated by controlling the temperature and time of the melt reaction.

[0017] In a second aspect, the present invention provides a method for preparing the polycitrate-modified artificial ligament as described in the first aspect, the preparation method comprising the following steps: The surfaces of both sides of the PET woven film are coated with polycitrate prepolymer, and then subjected to heat curing treatment to obtain a PET woven film modified with a polycitrate coating, which is then rolled to obtain the polycitrate modified artificial ligament.

[0018] Preferably, before coating the polycitrate prepolymer on both sides of the PET woven film, the method further includes subjecting the PET woven film to surface plasma treatment. Subjecting the PET woven film to surface plasma treatment can enrich the surface of the PET woven film with hydroxyl groups, thereby increasing its adhesion to polycitrate.

[0019] Preferably, the coating amount of the polycitrate prepolymer is 0.01-0.5g (for example, 0.01g, 0.03g, 0.05g, 0.08g, 0.1g, 0.15g, 0.2g, 0.25g, 0.3g, 0.35g, 0.4g, 0.45g, 0.5g, etc.) per square centimeter of PET woven film, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable. It should be noted that this coating amount is the mass of the polycitrate prepolymer required for double-sided coating) of the polycitrate prepolymer.

[0020] Preferably, the heat curing treatment includes an air blast heat curing treatment and a vacuum heat curing treatment performed sequentially.

[0021] Preferably, the temperature of the blast heat curing treatment is 60-100°C, for example 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable. The time of the blast heat curing treatment is 0.5-3 days, for example 0.5 day, 1 day, 1.5 days, 2 days, 2.5 days, 3 days, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] Preferably, the temperature of the vacuum heat curing treatment is 100-140°C, for example 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable. The time of the vacuum heat curing treatment is 2-24h, for example 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0023] As a preferred technical solution of the present invention, the preparation method comprises the following steps: The PET woven film is subjected to surface plasma treatment, and then 0.01-0.5 g of polycitrate prepolymer is coated on each square centimeter of the PET woven film, followed by a forced air heat curing treatment at 60-100°C for 0.5-3 days, and then a vacuum heat curing treatment at 100-140°C for 2-24 hours to obtain a PET woven film modified with a polycitrate coating, which is then curled to obtain the polycitrate modified artificial ligament.

[0024] Compared with the prior art, the present invention has the following beneficial effects: (1) Currently, PET artificial ligaments are non-degradable inert materials with poor biocompatibility and bone integration ability. The present invention improves the biocompatibility and osteogenic activity of artificial ligaments by modifying PET artificial ligaments with polycitrate. (2) Currently, the implantation of PET artificial ligaments will lead to inflammatory reactions between the bone tissues in the tunnel. The present invention improves the anti-inflammatory and antioxidant effects of PET artificial ligaments by using polycitrate to modify the PET artificial ligaments, and can improve chronic foreign body reactions (inflammation). (3) Although the current PET artificial ligaments have high strength and durability, they are significantly different from natural ligaments in terms of elasticity and mechanical adaptability. The present invention uses polycitrate to modify the PET artificial ligaments, which can better simulate the mechanical behavior of natural ligament tissue and improve the bone integration ability of the PET artificial ligaments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the SEM image of the polycitrate modified artificial ligament provided in Example 1.

[0026] Figure 2 This is the SEM image of the unmodified PET artificial ligament provided in Comparative Example 1.

[0027] Figure 3 This is a graph showing the tensile properties test results of the polycitrate modified artificial ligaments provided in Example 1, Example 4, and Example 5 and the unmodified PET artificial ligament provided in Comparative Example 1.

[0028] Figure 4 This is a graph showing the osteogenic activity test results of the polycitrate-modified artificial ligaments provided in Examples 1-3 and the unmodified PET artificial ligament provided in Comparative Example 1. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0030] Unless otherwise specified, the PET woven film used in the examples and comparative examples of the present invention is a medium-thickness woven film (thickness is 0.8 mm) with low density. Example 1

[0031] In this embodiment, a polycitrate modified artificial ligament is provided, and the preparation method comprises the following steps: (1) preparing poly(1,8-octanediol-citric acid) prepolymer by a melt method: mixing citric acid and 1,8-octanediol in a molar ratio of 1:1, and subjecting the mixture to a melt reaction at 140° C. for 30 min to obtain a poly(1,8-octanediol-citric acid) prepolymer having a molecular weight of 3000 Da; (2) The PET woven film is subjected to surface plasma treatment, and then the surfaces of both sides of the PET woven film are coated with polycitrate-1,8-octanediol prepolymer, with 0.1 g of polycitrate-1,8-octanediol prepolymer coated per square centimeter of the PET woven film, followed by a forced air heat curing treatment at 80°C for 2 days, and then a vacuum heat curing treatment at 140°C for 4 hours to obtain a PET woven film modified with a polycitrate coating, which is then rolled to obtain the polycitrate-modified artificial ligament. Example 2

[0032] In this embodiment, a polycitrate modified artificial ligament is provided, and the preparation method comprises the following steps: (1) Preparation of polyethylene citrate prepolymer by melt method: citric acid and ethylene glycol were mixed in a molar ratio of 1:1, and melt-reacted at 160° C. for 20 min to obtain polyethylene citrate prepolymer with a molecular weight of 2000 Da; (2) The PET woven film is subjected to surface plasma treatment, and then poly(ethylene glycol citrate) prepolymer is coated on both sides of the PET woven film. 0.1 g of poly(ethylene glycol citrate) prepolymer is coated per square centimeter of the PET woven film. The PET woven film is then subjected to blown heat curing treatment at 60°C for 3 days, and then subjected to vacuum heat curing treatment at 120°C for 12 hours to obtain a PET woven film modified with a poly(citrate) coating. The PET woven film is then rolled to obtain the poly(citrate) modified artificial ligament. Example 3

[0033] In this embodiment, a polycitrate modified artificial ligament is provided, and the preparation method comprises the following steps: (1) Preparing polycitric acid-1,4-butanediol prepolymer by a melt method: citric acid and 1,4-butanediol were mixed in a molar ratio of 1:1, and melt-reacted at 120° C. for 80 min to obtain a polycitric acid-1,4-butanediol prepolymer having a molecular weight of 5000 Da; (2) The PET woven film is subjected to surface plasma treatment, and then the surfaces of both sides of the PET woven film are coated with polycitrate-1,4-butylene glycol prepolymer, with 0.1 g of polycitrate-1,4-butylene glycol prepolymer coated on each square centimeter of the PET woven film. The PET woven film is then subjected to blown heat curing treatment at 100°C for 1 day, and then subjected to vacuum heat curing treatment at 100°C for 24 hours to obtain a PET woven film modified with a polycitrate coating, which is then rolled to obtain the polycitrate-modified artificial ligament. Example 4

[0034] The only difference between this embodiment and embodiment 1 is that in step (2), 0.3 g of poly(1,8-octanediol citrate) prepolymer is coated per square centimeter of the PET woven film. Example 5

[0035] The only difference between this embodiment and embodiment 1 is that in step (2), 0.5 g of poly(1,8-octanediol citrate) prepolymer is coated per square centimeter of the PET woven film.

[0036] Comparative Example 1 This comparative example provides an unmodified PET artificial ligament, which is rolled from a PET woven film.

[0037] The polycitrate modified artificial ligament provided in Example 1 and the unmodified PET artificial ligament provided in Comparative Example 1 were characterized by scanning electron microscopy (SEM), and the results were as follows: Figure 1 and Figure 2As shown, it can be seen that the surface of the artificial ligament modified with polycitrate is evenly loaded with a uniform polycitrate coating compared to the unmodified PET artificial ligament.

[0038] The tensile properties of the artificial ligaments modified with polycitrate provided in Example 1, Example 4, and Example 5 and the unmodified PET artificial ligament provided in Comparative Example 1 were tested. The test method was as follows: the artificial ligaments provided in Example 1, Example 4, Example 5, and Comparative Example 1 were placed in a universal testing machine for tensile properties testing at a tensile rate of 50 mm / min. The test results are shown in FIG. Figure 3 As shown, it can be seen that compared with the unmodified PET artificial ligament, the tensile properties of the artificial ligament modified with polycitrate are significantly enhanced, which is mainly related to the type of polycitrate and the amount of coating modification.

[0039] The osteogenic activity test was performed on the polycitrate-modified artificial ligaments provided in Examples 1-3 and the unmodified PET artificial ligament provided in Comparative Example 1, as follows: MC3T3-E1 cells were seeded in a six-well plate, 300,000 cells per well, and co-cultured with the artificial ligament for 3 days, followed by real-time PCR detection to detect osteogenic-related genes, including alkaline phosphatase (ALP), type I collagen (Col1), osteopontin (OPN), and Runt-related transcription factor 2 (Rnux2). The test results are shown in FIG. Figure 4 As shown, it can be seen that the artificial ligament modified with polycitrate has good osteogenic activity compared with the unmodified PET artificial ligament.

[0040] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the polycitrate modified artificial ligament and the preparation method thereof, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A polycitrate modified artificial ligament, characterized in that: The polycitrate modified artificial ligament is formed by rolling a PET woven film modified by a polycitrate coating.

2. The polycitrate modified artificial ligament according to claim 1, characterized in that: The polycitrate coating modified PET woven film comprises a PET woven film and a polycitrate coating arranged on both side surfaces and in the gap of the PET woven film.

3. The polycitrate modified artificial ligament according to claim 2, characterized in that: The polycitrate coating is obtained by curing the polycitrate prepolymer; The polycitrate prepolymer includes any one of polycitrate-1,8-octanediol prepolymer, polycitrate-ethylene glycol prepolymer, polycitrate-glycerol prepolymer, polycitrate-1,4-butylene glycol prepolymer, and polycitrate-caprolactone prepolymer, or a combination of at least two thereof; The molecular weight of the polycitrate prepolymer is 1000-10000Da.

4. The polycitrate modified artificial ligament according to claim 3, characterized in that: The polycitrate prepolymer is prepared by a melt reaction; The polycitrate prepolymer is prepared by the following method: The citric acid and the polyol are mixed and melt-reacted to obtain the polycitrate prepolymer, wherein the polyol includes any one of 1,8-octanediol, ethylene glycol, glycerol, 1,4-butanediol, and 6-hydroxyacetic acid, or a combination of at least two thereof.

5. The polycitrate modified artificial ligament according to claim 4, characterized in that: The molar ratio of citric acid to polyol is 1:(0.8-1.2); The temperature of the melting reaction is 120-160° C., and the time of the melting reaction is 10-90 minutes.

6. A method for preparing a polycitrate-modified artificial ligament as claimed in any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: The surfaces of both sides of the PET woven film are coated with polycitrate prepolymer, and then subjected to heat curing treatment to obtain a PET woven film modified with a polycitrate coating, which is then rolled to obtain the polycitrate modified artificial ligament.

7. The preparation method according to claim 6, characterized in that: Before coating the polycitrate prepolymer on both sides of the PET woven film, the method further includes a step of performing surface plasma treatment on the PET woven film.

8. The preparation method according to claim 6, characterized in that: The coating amount of the polycitrate prepolymer is 0.01-0.5 g of the polycitrate prepolymer per square centimeter of the PET woven film.

9. The preparation method according to claim 6, characterized in that: The heat curing treatment includes an air blast heat curing treatment and a vacuum heat curing treatment performed sequentially; The temperature of the blast heat curing treatment is 60-100°C, and the time of the blast heat curing treatment is 0.5-3 days; The temperature of the vacuum heat curing treatment is 100-140° C., and the time of the vacuum heat curing treatment is 2-24 hours.

10. The preparation method according to claim 6, characterized in that: The preparation method comprises the following steps: The PET woven film is subjected to surface plasma treatment, and then 0.01-0.5 g of polycitrate prepolymer is coated on each square centimeter of the PET woven film, followed by a forced air heat curing treatment at 60-100°C for 0.5-3 days, and then a vacuum heat curing treatment at 100-140°C for 2-24 hours to obtain a PET woven film modified with a polycitrate coating, which is then curled to obtain the polycitrate modified artificial ligament.

Images