Preparation method of anticoagulant coating based on polydopamine-astragalus polysaccharide phosphate

Abstract

The invention discloses a preparation method of an anticoagulant coating based on polydopamine-astragalus polysaccharide phosphate. The preparation method comprises the following steps: S1, constructing a polydopamine nano coating; and S2, preparing the astragalus polysaccharide sulfate coating. The anti-coagulation coating based on the polydopamine-astragalus polysaccharide phosphate has the technical effects and advantages that compared with the existing anti-coagulation coating, the anti-coagulation coating based on the polydopamine-astragalus polysaccharide phosphate shows remarkable advantages. Through self-polymerization of polydopamine, the adhesiveness of the coating and a substrate material is greatly improved, and the stability and durability of the coating are ensured. Meanwhile, due to the addition of the astragalus polysaccharide sulfate, the anticoagulation performance is effectively enhanced, the inhibition on platelet activity is reduced, and the risk of abnormal bleeding is reduced. In addition, the preparation method is simple in process, environment-friendly and easy to popularize. In conclusion, the anticoagulant coating has a wide application prospect in the biomedical field, and provides powerful support for improving the blood compatibility of medical instruments.

Description

Technical Field

[0001] The invention relates to the field of anticoagulant coating preparation, and more specifically to a method for preparing an anticoagulant coating based on polydopamine-astragalus polysaccharide phosphate. Background Art

[0002] Currently, the most commonly used biomedical anticoagulant coating is heparin coating. However, the biological activity of heparin coating will decrease after it is fixed on the surface of polymer materials. It will also reduce platelet activity and cause complications such as abnormal bleeding. Summary of the invention

[0003] In order to overcome the above-mentioned defects of the prior art, the present invention provides a method for preparing an anticoagulant coating based on polydopamine-astragalus polysaccharide phosphate, with the purpose of solving the problems of poor adhesion, poor anticoagulant effect, and easy occurrence of complications in the existing anticoagulant coating.

[0004] The technical solution of the present invention is as follows:

[0005] A method for preparing an anticoagulant coating based on polydopamine-astragalus polysaccharide phosphate comprises the following steps:

[0006] S1. Construction of polydopamine nanocoating, including:

[0007] The substrate material is pretreated, and the surface roughness and active groups are increased by acid treatment and physical methods to improve the adhesion of the polydopamine coating. 100 mL of a 2 wt% dopamine hydrochloride aqueous solution with a pH of 8.5 is prepared, and the pretreated substrate material is immersed in an alkaline solution containing dopamine, and a polydopamine coating is formed on the surface of the material by the self-polymerization reaction of dopamine under alkaline conditions. Stir at room temperature for 36 hours, take it out, rinse it with ultrapure water, vacuum dry it, and load a layer of polydopamine bottom layer on its surface.

[0008] The polydopamine-coated substrate is covalently bonded on the surface of the substrate containing amine or thiol groups through Michael addition and Schiff base reaction, and the polydopamine-coated substrate is immersed in a solution containing polymer precursors to form a polymer network through chemical cross-linking reaction.

[0009] During the intermediate modification process, polymers containing amine or aldehyde groups can react with the corresponding functional groups on the polydopamine coating through a Schiff base reaction to form stable covalent bonds.

[0010] S2. Preparation of astragalus polysaccharide sulfate coating, comprising

[0011] 2.1 Experimental materials and main instruments

[0012] 1) Astragalus polysaccharide after crude extraction and purification (alkali extraction and alcohol precipitation);

[0013] 2) ethanol;

[0014] 3) Sodium chloride;

[0015] 4) Sodium cyanoborohydride;

[0016] 5) 98% concentrated sulfuric acid;

[0017] 6) Sodium nitrite;

[0018] 2.2 Coating construction

[0019] (1) Pretreatment of medical devices / materials

[0020] Perform preliminary sterilization and disinfection on the blood-contact medical devices to be assembled, take out the blood-contact medical devices, rinse them with medical disinfectant, put them in a ventilated place to air-dry, and then sterilize them with ethylene oxide, and store them in a stainless steel box at room temperature and pressure for standby use;

[0021] (2) Sulfation treatment of astragalus polysaccharide

[0022] First, the astragalus polysaccharide after alkali extraction, alcohol precipitation and purification is dehydrated and dried. Secondly, according to the ratio of concentrated sulfuric acid to astragalus polysaccharide of 6:1, astragalus polysaccharide is quickly added to concentrated sulfuric acid, and after stirring and reacting at 0°C for 4 hours, the pH of the reaction system is adjusted to weak alkalinity to obtain astragalus polysaccharide sulfate solution; finally, the obtained solution is dialyzed for 20 hours, poured into 2 times the volume of 95% ethanol, and precipitated; after standing, the precipitate is filtered out and dried to obtain astragalus polysaccharide sulfate;

[0023] (3) Preparation of coating

[0024] First, polysaccharide sulfate or collagen is dissolved in deionized water, a certain amount of sodium nitrite is added, and the mixture is stirred in an ice bath under acidic conditions for 2 hours; the pH of the solution is adjusted to neutral, and then dialyzed for 24 hours, during which the deionized water is replaced 3 times to obtain a polysaccharide sulfate coating solution and a collagen coating solution.

[0025] Secondly, add appropriate amounts of sodium chloride and sodium cyanoborohydride to the obtained polysaccharide sulfate coating liquid and collagen coating liquid, mix them thoroughly, and adjust the solution pH to 3.5; immerse the blood-contact medical device material in the polysaccharide sulfate coating liquid, shake and react in a constant temperature water bath at 40°C for 2 hours, take it out and wash the polysaccharide sulfate that is not firmly bound to the surface with deionized water, and blow it dry with nitrogen. The dried blood-contact medical device material is immediately immersed in the collagen coating liquid, shake and react in a constant temperature water bath at 40°C for 2 hours, take it out and wash the collagen that is not firmly bound to the surface with deionized water, and blow it dry with nitrogen. Repeat the above process 4 times, and after drying, obtain the target blood-contact medical device with a composite anticoagulant coating of astragalus polysaccharide phosphate coating.

[0026] Technical effects and advantages of the present invention:

[0027] Compared with the currently available anticoagulant coatings, the anticoagulant coating based on polydopamine-astragalus polysaccharide phosphate proposed in the present invention shows significant advantages. Through the self-polymerization of polydopamine, the adhesion between the coating and the substrate material is greatly improved, ensuring the stability and durability of the coating. At the same time, the addition of astragalus polysaccharide sulfate not only effectively enhances the anticoagulant performance, but also reduces the inhibition of platelet activity and reduces the risk of abnormal bleeding. In addition, the preparation method is simple in process, environmentally friendly, and easy to promote. In summary, the anticoagulant coating of the present invention has broad application prospects in the biomedical field and provides strong support for improving the blood compatibility of medical devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall process of the present invention. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] like Figure 1 The method for preparing an anticoagulant coating based on polydopamine-astragalus polysaccharide phosphate comprises the following steps:

[0031] S1. Construction of polydopamine nanocoating, including:

[0032] The substrate material is pretreated, and the surface roughness and active groups are increased by acid treatment and physical methods to improve the adhesion of the polydopamine coating. 100 mL of a 2 wt% dopamine hydrochloride aqueous solution with a pH of 8.5 is prepared, and the pretreated substrate material is immersed in an alkaline solution containing dopamine, and a polydopamine coating is formed on the surface of the material by the self-polymerization reaction of dopamine under alkaline conditions. Stir at room temperature for 36 hours, take it out, rinse it with ultrapure water, vacuum dry it, and load a layer of polydopamine bottom layer on its surface.

[0033] The polydopamine-coated substrate is covalently bonded on the surface of the substrate containing amine or thiol groups through Michael addition and Schiff base reaction, and the polydopamine-coated substrate is immersed in a solution containing polymer precursors to form a polymer network through chemical cross-linking reaction.

[0034] During the intermediate modification process, polymers containing amine or aldehyde groups can react with the corresponding functional groups on the polydopamine coating through a Schiff base reaction to form stable covalent bonds.

[0035] S2. Preparation of astragalus polysaccharide sulfate coating, comprising

[0036] 2.1 Experimental materials and main instruments

[0037] 1) Astragalus polysaccharide after crude extraction and purification (alkali extraction and alcohol precipitation);

[0038] 2) ethanol;

[0039] 3) Sodium chloride;

[0040] 4) Sodium cyanoborohydride;

[0041] 5) 98% concentrated sulfuric acid;

[0042] 6) Sodium nitrite;

[0043] 2.2 Coating construction

[0044] (1) Pretreatment of medical devices / materials

[0045] Perform preliminary sterilization and disinfection on the blood-contact medical devices to be assembled, take out the blood-contact medical devices, rinse them with medical disinfectant, put them in a ventilated place to air-dry, and then sterilize them with ethylene oxide, and store them in a stainless steel box at room temperature and pressure for standby use;

[0046] (2) Sulfation treatment of astragalus polysaccharide

[0047] First, the astragalus polysaccharide after alkali extraction, alcohol precipitation and purification is dehydrated and dried. Secondly, according to the ratio of concentrated sulfuric acid to astragalus polysaccharide of 6:1, astragalus polysaccharide is quickly added to concentrated sulfuric acid, and after stirring and reacting at 0°C for 4 hours, the pH of the reaction system is adjusted to weak alkalinity to obtain astragalus polysaccharide sulfate solution; finally, the obtained solution is dialyzed for 20 hours, poured into 2 times the volume of 95% ethanol, and precipitated; after standing, the precipitate is filtered out and dried to obtain astragalus polysaccharide sulfate;

[0048] (3) Preparation of coating

[0049] First, polysaccharide sulfate or collagen is dissolved in deionized water, a certain amount of sodium nitrite is added, and the mixture is stirred in an ice bath under acidic conditions for 2 hours; the pH of the solution is adjusted to neutral, and then dialyzed for 24 hours, during which the deionized water is replaced 3 times to obtain a polysaccharide sulfate coating solution and a collagen coating solution.

[0050] Secondly, add appropriate amounts of sodium chloride and sodium cyanoborohydride to the obtained polysaccharide sulfate coating liquid and collagen coating liquid, mix them thoroughly, and adjust the solution pH to 3.5; immerse the blood-contact medical device material in the polysaccharide sulfate coating liquid, shake and react in a constant temperature water bath at 40°C for 2 hours, take it out and wash the polysaccharide sulfate that is not firmly bound to the surface with deionized water, and blow it dry with nitrogen. The dried blood-contact medical device material is immediately immersed in the collagen coating liquid, shake and react in a constant temperature water bath at 40°C for 2 hours, take it out and wash the collagen that is not firmly bound to the surface with deionized water, and blow it dry with nitrogen. Repeat the above process 4 times, and after drying, obtain the target blood-contact medical device with a composite anticoagulant coating of astragalus polysaccharide phosphate coating.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an anticoagulant coating based on polydopamine-astragalus polysaccharide phosphate, characterized in that: The following steps are involved: S1. Construction of polydopamine nanocoating, including: The substrate material is pretreated to increase the surface roughness and active groups by acid treatment and physical methods, thereby improving the adhesion of the polydopamine coating; 100 mL of a 2 wt% dopamine hydrochloride aqueous solution with a pH of 8.5 is prepared, and the pretreated substrate material is immersed in an alkaline solution containing dopamine, and a polydopamine coating is formed on the surface of the material by utilizing the self-polymerization reaction of dopamine under alkaline conditions; the substrate material is stirred at room temperature for 36 hours, taken out, rinsed with ultrapure water, and vacuum dried, and a layer of polydopamine bottom layer is loaded on the surface of the substrate material; S2. Preparation of astragalus polysaccharide sulfate coating, comprising: (1) Pretreatment of medical devices / materials Perform preliminary sterilization and disinfection on the blood-contact medical devices to be assembled, take out the blood-contact medical devices, rinse them with medical disinfectant, put them in a ventilated place to air-dry, and then sterilize them with ethylene oxide, and store them in a stainless steel box at room temperature and pressure for standby use; (2) Sulfation treatment of astragalus polysaccharide First, the astragalus polysaccharide after alkali extraction, alcohol precipitation and purification is dehydrated and dried; secondly, according to the ratio of concentrated sulfuric acid to astragalus polysaccharide substance of 6:1, astragalus polysaccharide is quickly added to concentrated sulfuric acid, and after stirring and reacting at 0°C for 4 hours, the pH of the reaction system is adjusted to weak alkalinity to obtain an astragalus polysaccharide sulfate solution; finally, the obtained solution is dialyzed for 20 hours, poured into 2 times the volume of 95% ethanol, and precipitated; after standing, the precipitate is filtered out and dried to obtain astragalus polysaccharide sulfate; (3) Preparation of coating First, polysaccharide sulfate or collagen is dissolved in deionized water, a certain amount of sodium nitrite is added, and the mixture is stirred in an ice bath under acidic conditions for 2 hours; the pH of the solution is adjusted to neutral, and then dialyzed for 24 hours, during which the deionized water is replaced 3 times, to obtain a polysaccharide sulfate coating solution and a collagen coating solution; Secondly, add appropriate amounts of sodium chloride and sodium cyanoborohydride to the obtained polysaccharide sulfate coating liquid and collagen coating liquid respectively, mix them thoroughly, and adjust the pH of the solution to 3.5; immerse the blood-contact medical device material in the polysaccharide sulfate coating liquid, shake and react in a constant temperature water bath at 40°C for 2 hours, take out and wash the polysaccharide sulfate that is not firmly bound to the surface with deionized water, and blow dry with nitrogen; the dried blood-contact medical device material is immediately immersed in the collagen coating liquid, shake and react in a constant temperature water bath at 40°C for 2 hours, take out and wash the collagen that is not firmly bound to the surface with deionized water, and blow dry with nitrogen; repeat the above process 4 times, and after drying, obtain the target blood-contact medical device with a composite anticoagulant coating of astragalus polysaccharide phosphate coating.

2. The method for preparing an anticoagulant coating based on polydopamine-astragalus polysaccharide phosphate according to claim 1, characterized in that: In S1, covalent bonding is performed on the surface of a substrate containing amine or thiol groups through Michael addition and Schiff base reaction, the polydopamine-coated substrate is immersed in a solution containing a polymer precursor, and a polymer network is formed through a chemical cross-linking reaction.

3. The method for preparing an anticoagulant coating based on polydopamine-astragalus polysaccharide phosphate according to claim 1, characterized in that: In S1, during the intermediate modification process, the polymer containing an amine group or an aldehyde group can react with the corresponding functional group on the polydopamine coating through a Schiff base reaction to form a stable covalent bond.

4. The method for preparing an anticoagulant coating based on polydopamine-astragalus polysaccharide phosphate according to claim 1, characterized in that: In step S2, the experimental materials and main instruments include: 1) Alkaline extraction and alcohol precipitation of astragalus polysaccharide after crude extraction and purification; 2) ethanol; 3) Sodium chloride; 4) Sodium cyanoborohydride; 5) 98% concentrated sulfuric acid; 6) Sodium nitrite.

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