Composite heparin anticoagulant coating and preparation method thereof

Abstract

The invention relates to the field of medical instruments, in particular to a composite heparin anticoagulant coating and a preparation method thereof. The method comprises the following steps: ultraviolet light pretreatment: carrying out ultraviolet light pretreatment on a substrate material to initiate polyethyleneimine to be grafted on the surface of the material; turning coating: coating the surface of the substrate material with a heparin solution, and fixing with an EDC solution; and the coating direction is changed in the coating process. Amino chains are introduced to the surface of a substrate material through ultraviolet light, the surface is provided with positive charges, and the heparin coating is formed through ionic bond combination. After the coating is completed, the coating is fixed by using an EDC solution, and the coating direction is changed in the coating process, so that the stability, the uniformity, the hydrophilicity and the anticoagulation performance of the coating are improved.

Description

Technical Field

[0001] The invention relates to the field of medical devices, and in particular to a composite heparin anticoagulant coating and a preparation method thereof. Background Art

[0002] Blood-contact medical devices often have poor biocompatibility and blood compatibility, which leads to plasma protein adsorption on the material surface after contact with blood, resulting in blood coagulation and even thrombosis. Therefore, it is crucial to modify the surface of polymer biomaterials used in medical devices that come into contact with human blood and introduce anticoagulants to reduce platelet adhesion and avoid thrombosis.

[0003] Polymer biomaterials used in blood-contact medical devices include polyethylene (PE), polypropylene (PP), polycarbonate (PC), poly(4-methyl-1-pentene) (PMP) and polyvinyl chloride (PVC). Common surface modification strategies mainly include constructing inert membrane surfaces, introducing bioactive substances, and surface biomimetic modification. However, physical modification methods are currently used for substrate materials. The surface is modified by introducing active substances through coating, which has poor stability and is easy to fall off.

[0004] Ultraviolet light grafting is the process of generating active free radicals on the surface of the grafted material under ultraviolet light irradiation, which in turn triggers the material to undergo a chain growth reaction to generate grafted chains, thereby improving the hydrophilicity and biocompatibility of the material.

[0005] Heparin is a naturally occurring linear polysaccharide composed of glucosamine, L-iduronide, N-acetylglucosamine and D-glucuronic acid in alternating forms. It is mainly located in the granules of mast cells and can provide natural anticoagulant surface activity for vascular endothelial cells. It prevents thrombosis by interacting with antithrombin III (AT III) after contact with blood. It is widely used in clinical practice to prevent and treat thromboembolic diseases, early treatment of disseminated intravascular coagulation and in vitro anticoagulation. At present, the technology of heparin coating mainly falls into two categories: physical coating and chemical covalent grafting. However, the coating uniformity and stability of the existing technology are poor, and it is easy to be eluted over time.

[0006] CN115990297 A discloses a heparin anticoagulant coating based on PTFE material and a method for preparing the heparin anticoagulant coating. The PTFE material is first treated with oxygen plasma, dopamine and APTMS are coated on the surface of the activated PTFE by dip coating to introduce active amino groups, and then a dense acrylic acid homopolymer (pHPA) is fixed. The PTFE material coated with the pHPA coating is then immersed in a heparin solution containing active carboxyl groups, incubated and heparin grafting is completed to obtain the heparin coating. The preparation process is relatively complicated, and the immersion coating results in a low utilization rate.

[0007] CN111544646 A discloses a small-caliber artificial blood vessel with a heparin coating grafted on the surface and a method for preparing a small-caliber artificial blood vessel, wherein the surface of the substrate is immersed in a dopamine solution for reaction, a multi-layer polydopamine coating is coated, and then grafted with polyethyleneimine through chemical bonding, and finally heparin is activated using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS), and a heparinized surface is obtained through amide bonding. Dopamine is physically coated on the substrate surface, and there is a disadvantage that the heparin coating is easily detached along with the dopamine coating. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides a composite heparin anticoagulant coating and a preparation method thereof.

[0009] At present, the anticoagulant coatings used in medical devices mostly use physical blending and ion adsorption to coat the surfactant on the surface, and the coating stability and uniformity are poor. In addition, the coating process is mostly static immersion or unidirectional coating. Therefore, the present invention proposes a method for preparing a heparin coating by using ultraviolet light to pretreat the substrate and then directional coating to improve the stability, uniformity, hydrophilicity and anticoagulant properties of the coating.

[0010] Specifically, the preparation method of the composite heparin anticoagulant coating provided in the first aspect of the present invention comprises: 1) UV pretreatment: UV pretreatment is performed on the substrate material to initiate polyethyleneimine (PEI) grafting onto the surface of the material.

[0011] 2) Directional coating: Use heparin solution to coat the surface of the base material, and fix it with EDC solution; change the coating direction in the middle of coating. The present invention introduces amino chains on the surface of the base material through ultraviolet light, and the surface has a positive charge. Heparin combines with it through ionic bonds to form a heparin coating. However, the heparin coating formed by ionic bonds cannot be preserved for a long time under the binding of hydrophilic proteins and blood flow flushing. After the coating is completed, the coating is fixed with EDC solution to enhance stability, and the coating direction is changed in the middle of coating, thereby improving the stability, uniformity, hydrophilicity and anticoagulant properties of the coating.

[0012] The invention realizes uniform coating of the heparin coating and enhances the stability of the coating by using the heparin solution and the EDC solution to cyclically flush and change the direction of the substrate material.

[0013] Preferably, the heparin solution is circulated and flushed at room temperature for 1-4 hours, and the circulation direction is changed and the circulation flushing is continued for 1-4 hours. For example, the circulation flushing time and the circulation flushing time after changing the circulation direction can be 1 hour, 1.5 hours, 1.8 hours, 2 hours, 2.2 hours, 2.5 hours, 3 hours, 3.5 hours, 3.8 hours, 4 hours, etc., and any values ​​and ranges therebetween.

[0014] More preferably, the EDC solution is circulated and flushed at room temperature for 0.5-2 h, and the circulation direction is changed and then the circulation is continued for 0.5-2 h.

[0015] More preferably, the flow rate of the heparin solution and / or EDC solution for circulatory flushing is 0.05-0.5 LPM, for example, the flow rate is 0.08 LPM, 0.09 LPM, 0.1 LPM, 0.2 LPM, 0.3 LPM, 0.4 LPM, etc., and any value and range therebetween.

[0016] The flow rate within the preferred range enables the heparin and EDC solutions to fully contact the surface of the substrate material, ensuring their uniform coating and reaction.

[0017] More preferably, the solvent of the heparin solution and / or the EDC solution is disodium hydrogen phosphate-citric acid buffer solution.

[0018] More preferably, the mass fraction of the heparin solution is 0.05%-0.3%, and the pH is 2-5. For example, the mass fraction is 0.05%, 0.06%, 0.08%, 0.09%, 0.1%, 0.15%, 0.2%, 0.25%, 0.28%, 0.3%, etc., and any value and range therebetween.

[0019] It is further preferred that the mass fraction of the EDC solution is 0.002‰-0.03‰ and the pH is 2-6. For example, the mass fraction is 0.002‰, 0.003‰, 0.004‰, 0.005‰, 0.006‰, 0.008‰, 0.009‰, 0.01‰, 0.015‰, 0.02‰, 0.025‰, 0.028‰, 0.03‰, etc., and any numerical value and range therebetween. A heparin solution having a mass fraction of 0.05%-0.3% and a pH of 2-5 is prepared by a disodium hydrogen phosphate-citric acid buffer solution to ensure that heparin plays a better role. The mass fraction of the EDC solution is 0.002‰-0.03‰, the pH is 2-6, and it is also prepared by a disodium hydrogen phosphate-citric acid buffer solution to better ensure reaction activity and efficiency.

[0020] Preferably, the ultraviolet light pretreatment in step 1) includes plasma-ultraviolet pretreatment or ultraviolet-ozone pretreatment.

[0021] In the present invention, the UV pretreatment is to modify the surface of the substrate material under UV irradiation, initiate PEI grafting on the surface of the material, and pretreat the material to improve its hydrophilicity and biological activity, etc. Preferably, the substrate material is UV pretreated without a photosensitizer, and free radicals or oxygen-containing groups are generated on the surface of the material by plasma-UV or UV-ozone treatment.

[0022] Preferably, the plasma-ultraviolet pretreatment comprises: 1) Place the substrate material in an argon plasma environment for treatment.

[0023] 2) Treating the treated substrate material in an environment containing O2.

[0024] 3) Mixing the PEI solution with the substrate material and reacting them under ultraviolet irradiation. The present invention places the substrate material in an argon plasma environment to treat it so that free radicals are generated on its surface. The treated substrate material is exposed to air (O2 environment), and peroxide groups are formed on the surface of the material. It is placed in a PEI solution, and the peroxide groups are decomposed into free radical initiating substances under ultraviolet irradiation, which are grafted on its surface to form grafted chains.

[0025] Preferably, in step 1), the PMP hollow fiber membrane is placed in an argon plasma environment for treatment for 10-15 min.

[0026] Preferably, in step 2), the treatment is carried out in air for 10-15 min.

[0027] Preferably, in step 3), the solvent of the PEI solution is a phosphate buffer solution with a configuration mass fraction of 1%-16%; the reaction is carried out in an ice water bath and at a stirring speed of 35-75 rpm, and the reaction time is 20-30 min.

[0028] Preferably, after step 3), the method further comprises washing with deionized water for 12-24 hours and freeze-drying.

[0029] Preferably, the UV-ozone pretreatment comprises: 1) Place the substrate material under a low-pressure mercury vapor lamp for activation.

[0030] 2) Mix the PEI solution with the substrate material and react under UV irradiation.

[0031] In the present invention, the substrate material is placed under a low-pressure mercury vapor lamp, the surface of the substrate material is activated, a series of oxygen-containing groups are generated, and then PEI is grafted on the surface to form graft chains.

[0032] Preferably, in step 1), the low-pressure mercury vapor lamp emits ultraviolet light with wavelengths of 253.7 nm and 184.9 nm; and the activation treatment time is 10-20 min.

[0033] Preferably, in step 2), the solvent of the PEI solution is a phosphate buffer solution with a configuration mass fraction of 1%-16%; the reaction is carried out in an ice water bath and at a stirring speed of 35-75 rpm, and the reaction time is 20-30 min.

[0034] Preferably, after step 2), the method further comprises washing with deionized water for 12-24 hours and freeze-drying.

[0035] Preferably, the substrate material is a PMP hollow fiber membrane.

[0036] As a specific implementation, the plasma-ultraviolet pretreatment comprises the following steps: S1. Place the PMP hollow fiber membrane in an argon plasma environment for 10-15 min to generate free radicals on the PMP surface.

[0037] S2. The PMP hollow fiber membrane with free radicals generated on the surface is exposed to air for 10-15 min (O2 environment), and peroxide groups are formed on the surface of the hollow fiber membrane.

[0038] S3. Use phosphate buffer solution (PBS) to prepare a PEI solution with a mass fraction of 1-16%.

[0039] S4. Transfer the PEI solution with a mass fraction of 1%-16% into a three-necked flask, then move the PMP hollow fiber membrane into the three-necked flask, introduce nitrogen into the flask for 15-30 min, exhaust all oxygen, turn on the UV lamp, and keep the whole process in an ice water bath and a dynamic environment (set the stirring speed to 50 rpm) for 20-30 min.

[0040] S5. Take out the PMP hollow fiber membrane, wash it with deionized water for 12-24 h to remove the unreacted substances and the generated copolymers, and finally place it in a freeze drying box for freeze drying.

[0041] As a specific implementation, the UV-ozone pretreatment comprises the following steps: S1. After the PMP hollow fiber membrane is placed under a low-pressure mercury vapor lamp (which can simultaneously emit ultraviolet light with wavelengths of 253.7 nm and 184.9 nm) for 10-20 min, the surface of the PMP hollow fiber membrane is activated and a series of oxygen-containing groups are generated.

[0042] S2. Use PBS to prepare a PEI solution with a mass fraction of 1-16%.

[0043] S3. Transfer the PEI solution with a mass fraction of 1-16% into a three-necked flask, then move the PMP hollow fiber membrane into the three-necked flask, introduce nitrogen into the flask for 15-30 min, exhaust all oxygen, turn on the UV lamp, and keep the whole process in an ice water bath and a dynamic environment (set the stirring speed to 50 rpm) for 20-30 min.

[0044] S4. Take out the PMP hollow fiber membrane, wash it with deionized water for 12-24 h to remove the unreacted substances and the generated copolymers, and finally place it in a freeze drying box for freeze drying.

[0045] The second aspect of the present invention provides a composite heparin anticoagulant coating prepared by the above preparation method.

[0046] The third aspect of the present invention provides the use of the composite heparin anticoagulant coating obtained by the above-mentioned preparation method in blood-contacting medical devices.

[0047] The beneficial effects of the present invention are at least: (1) The present invention generates free radicals or oxygen-containing groups on the surface of the substrate material by ultraviolet excitation, and then grafts substances onto the surface to modify its hydrophilicity and biocompatibility, thereby improving the stability of the coating.

[0048] (2) The present invention does not require a photosensitizer. Free radicals or oxygen-containing groups are generated on the surface of the substrate material by plasma-ultraviolet or ultraviolet-ozone. The heparin coating prepared by grafting the substance and coating it with a heparin solution has a good anticoagulant effect.

[0049] (3) The present invention changes the coating direction during coating, thereby achieving coating uniformity, increasing heparin coverage, and improving the hydrophilicity and anticoagulant effect of the heparin coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 A diagram of the plasma-ultraviolet pretreatment concept provided for an embodiment of the present invention.

[0052] Figure 2 A diagram of the UV-ozone pretreatment concept provided in an embodiment of the present invention.

[0053] Figure 3The water contact angle graphs of the surface of the PMP hollow fiber membrane before and after the UV pretreatment provided in the embodiments of the present invention, wherein (a) is a water contact angle graph of the untreated PMP hollow fiber membrane, (b) is a water contact angle graph of the PMP hollow fiber membrane after plasma-UV pretreatment (Example 1), and (c) is a water contact angle graph of the PMP hollow fiber membrane after UV-ozone pretreatment (Example 2).

[0054] Figure 4 The figures are the verification results of toluidine blue staining provided in the embodiments of the present invention, wherein (a) is the staining picture of the untreated PMP hollow fiber membrane, (b) is the staining picture of the PMP hollow fiber membrane directly coated with heparin, (c) is the staining picture of the PMP hollow fiber membrane coated with heparin after plasma-UV pretreatment (Example 1), and (d) is the staining picture of the PMP hollow fiber membrane coated with heparin after UV-ozone pretreatment (Example 2).

[0055] Figure 5 The water contact angle graphs of the heparin coatings provided in the embodiments of the present invention, wherein (a) is a water contact angle graph of a PMP hollow fiber membrane directly coated with heparin, (b) is a water contact angle graph of a PMP hollow fiber membrane coated with heparin after plasma-UV pretreatment (Example 1), and (c) is a water contact angle graph of a PMP hollow fiber membrane coated with heparin after UV-ozone pretreatment (Example 2).

[0056] Figure 6 The anticoagulant effect of the heparin coating prepared in the embodiment of the present invention is detected, wherein (a) is a picture of the untreated PMP hollow fiber membrane after contacting with blood for 6 hours, (b) is a picture of the PMP hollow fiber membrane directly coated with heparin after contacting with blood for 6 hours, (c) is a picture of the PMP hollow fiber membrane (Example 1) coated with heparin after plasma-UV pretreatment after contacting with blood for 6 hours, and (d) is a picture of the PMP hollow fiber membrane (Example 2) coated with heparin after UV-ozone pretreatment after contacting with blood for 6 hours.

[0057] Figure 7 The figures are the staining results of the heparin coating prepared by directional coating according to the embodiment of the present invention, wherein (a) is the front and back staining picture of the PMP hollow fiber membrane with unidirectional coating after pretreatment, and (b) is the front and back staining picture of the PMP hollow fiber membrane with directional coating after pretreatment.

[0058] Figure 8 The figures are the results of heparin coating staining using different flow rates of cyclic flushing and reverse flushing in this embodiment, wherein (a) is a staining picture of the PMP hollow fiber membrane after cyclic flushing and reverse flushing at a flow rate of 1 LPM, and (b) is a staining picture of the PMP hollow fiber membrane after cyclic flushing and reverse flushing at a flow rate of 0.3 LPM.

[0059] Fig. 9 The figures are the staining results of cyclic flushing and reverse flushing at different times when heparin was coated in this embodiment, wherein (a) is a staining picture of the PMP hollow fiber membrane after cyclic flushing and reverse flushing for 0.5 h each, and (b) is a staining picture of the PMP hollow fiber membrane after cyclic flushing and reverse flushing for 2 h each.

[0060] Fig.10 The figures are the staining results of the heparin coating coated with different concentrations of heparin solutions in this embodiment, wherein (a) is a staining picture of the PMP hollow fiber membrane coated with 0.03% heparin solution, and (b) is a staining picture of the PMP hollow fiber membrane coated with 0.3% heparin solution.

[0061] Fig.11 The figures are the staining results of the heparin coating fixed by EDC solutions of different concentrations in this embodiment, wherein (a) is the staining picture of the PMP hollow fiber membrane fixed by 0.001‰ EDC solution, and (b) is the staining picture of the PMP hollow fiber membrane fixed by 0.03‰ EDC solution. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. 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.

[0063] It should be understood that the following examples are only exemplary illustrations and explanations of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect. Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available products, or can be prepared by known methods. If the specific technology or conditions are not specified in the examples, they are all conventional methods or carried out according to the technology or conditions described in the literature of the field, or according to the product instructions. The reagents and instruments used, etc., which do not indicate the manufacturer, are all conventional products that can be purchased through regular channels.

[0064] The implementation steps of the present invention are as follows, taking PMP hollow fiber membrane as an example: Example 1 This embodiment provides a method for preparing a heparin coating by plasma-ultraviolet pretreatment of a PMP hollow fiber membrane and directional coating ( Figure 1 ), the steps are as follows.

[0065] S1. Place the PMP hollow fiber membrane in an argon plasma environment for 10 min to generate free radicals on the PMP surface.

[0066] S2. The PMP hollow fiber membrane with free radicals generated on the surface was exposed to air for 15 min (O2 environment), and peroxide groups were formed on the surface of the hollow fiber membrane.

[0067] S3. Use PBS to prepare a 10% PEI solution.

[0068] S4. Transfer the 10% PEI solution into a three-necked flask, then move the PMP hollow fiber membrane into the three-necked flask, introduce nitrogen into the flask for 20 min, exhaust all oxygen, turn on the UV lamp, and keep the whole process in an ice water bath and a dynamic environment (set the stirring speed to 50 rpm) for 25 min.

[0069] S5. Take out the PMP hollow fiber membrane, wash it with deionized water for 24 h to remove the unreacted substances and the generated copolymers, and finally place it in a freeze drying box for freeze drying.

[0070] S6. Build a coating circuit device.

[0071] S7. Use sodium hydrogen phosphate-citrate buffer solution to prepare a heparin solution with a mass fraction of 0.3% and a pH of 3-4.

[0072] S8. Circulate and flush at a flow rate of 0.3 LPM for 2 hours at room temperature, then change the circulation direction and continue to circulate and flush for 2 hours.

[0073] S9. Remove the solution from the circuit.

[0074] S10. Use sodium hydrogen phosphate-citric acid buffer solution to prepare an EDC solution with a mass fraction of 0.03‰ and a pH of 5-6.

[0075] S11. Circulate and flush at a flow rate of 0.3 LPM for 0.5 h at room temperature. After changing the circulation direction, continue to circulate and flush for 0.5 h.

[0076] S12. Remove the solution in the circuit.

[0077] S13. Place the coated object in an oven and dry for 8 h.

[0078] Example 2 This embodiment provides a method for preparing a heparin coating by UV-ozone pretreatment of a PMP hollow fiber membrane and directional coating ( Figure 2 ), the steps are as follows.

[0079] S1. After the PMP hollow fiber membrane was placed under a low-pressure mercury vapor lamp (which can simultaneously emit ultraviolet light with wavelengths of 253.7 nm and 184.9 nm) for 15 min, the surface of the PMP hollow fiber membrane was activated and a series of oxygen-containing groups were generated.

[0080] S2. Use PBS to prepare a 10% PEI solution.

[0081] S4. Transfer the 10% PEI solution into a three-necked flask, then move the PMP hollow fiber membrane into the three-necked flask, introduce nitrogen into the flask for 20 min, exhaust all oxygen, turn on the UV lamp, and keep the whole process in an ice water bath and a dynamic environment (set the stirring speed to 50 rpm) for 25 min.

[0082] S5. Take out the PMP hollow fiber membrane, wash it with deionized water for 24 h to remove the unreacted substances and the generated copolymers, and finally place it in a freeze drying box for freeze drying.

[0083] S6. Build a coating circuit device.

[0084] S7. Use sodium hydrogen phosphate-citrate buffer solution to prepare a heparin solution with a mass fraction of 0.3% and a pH of 3-4.

[0085] S8. Circulate and flush at a flow rate of 0.3 LPM for 2 hours at room temperature, then change the circulation direction and continue to circulate and flush for 2 hours.

[0086] S9. Remove the solution from the circuit.

[0087] S10. Use sodium hydrogen phosphate-citric acid buffer solution to prepare an EDC solution with a mass fraction of 0.03‰ and a pH of 5-6.

[0088] S11. Circulate and flush at a flow rate of 0.3 LPM for 0.5 h at room temperature. After changing the circulation direction, continue to circulate and flush for 0.5 h.

[0089] S12. Remove the solution in the circuit.

[0090] S13. Place the coated object in an oven and dry for 8 h.

[0091] Example 3 The same treatment method as in Example 1 was used, except that the flow rates of the circulating flushing and the reverse flushing were changed to 1 LPM when coating heparin.

[0092] Example 4 The same treatment method as in Example 2 was used, except that the time of the cyclic flushing and the reverse flushing was changed to 0.5 h during the heparin coating.

[0093] Example 5 The same treatment method as in Example 1 was used, except that the heparin solution during coating was 0.03%.

[0094] Example 6 The same treatment method as in Example 2 was used, except that the EDC solution used to fix the coating was 0.001‰.

[0095] Comparative Example 1 The same treatment method was used as in Example 1 and Example 2, except that the PMP hollow fiber membrane was directly coated with heparin without UV pretreatment.

[0096] Comparative Example 2 The same treatment method as in Example 1 was used, except that after the PMP hollow fiber membrane was UV pretreated, heparin was only coated unidirectionally.

[0097] Testing and Characterization (1) Hydrophilic properties of PMP hollow fiber membranes before and after UV pretreatment (Examples 1 and 2).

[0098] The results are as follows Figure 3 As shown in the figure, the contact angle of water on the surface of PMP was detected before and after pretreatment at room temperature, which verified that PMP was a hydrophobic material. After pretreatment, the water contact angle decreased from 95.5° to 90.3° (or 89.8°), indicating that the hydrophilicity of PMP was improved after grafting.

[0099] (2) After UV pretreatment and heparin coating, the uniformity and coverage of the heparin coating changed (Examples 1 and 2).

[0100] The heparin coating coverage was tested using the toluidine blue staining method. After the dye was adsorbed onto the negatively charged heparin surface, the dye color changed from blue to purple. Figure 4 As shown, the heparin coating was directly performed without UV pretreatment (Comparative Example 1), and the staining result was not obvious, showing a light blue-purple color, indicating that only a small amount of heparin coating adhered to the surface of the PMP hollow fiber, and the coating effect was not good. However, after UV pretreatment and then coating, the surface of the PMP hollow fiber was uniformly purple, indicating that the heparin coating evenly covered its surface, indicating that UV pretreatment and then coating were conducive to the adhesion of the heparin coating on the PMP surface.

[0101] (3) Hydrophilic properties of heparin coatings prepared after UV pretreatment combined with heparin coating (Examples 1 and 2).

[0102] The results are as follows Figure 5As shown, the water contact angles of the PMP hollow fiber membranes directly coated with heparin without UV pretreatment (Comparative Example 1) and the PMP hollow fiber membranes coated after UV pretreatment were tested at room temperature. It can be seen from the figure that after heparin coating after pretreatment, the water contact angle decreased from 87.4° to 75.1° (or 74.7°), indicating that the heparin coating formed by UV pretreatment of the grafted material and then coating has better hydrophilicity and can increase the coating effect of the heparin coating.

[0103] (4) Anticoagulant properties of heparin coating after UV pretreatment (Examples 1 and 2).

[0104] The anticoagulant effect of the heparin coating was tested by coagulation experiments. Figure 6 As shown, a large number of spot-like thrombi are attached to the surface of the untreated PMP hollow fiber membrane (Comparative Example 1) after contact with blood for 6 hours. A small amount of thrombi are also formed on the surface of the fiber membrane that is directly coated with heparin without UV pretreatment after contact with blood for 6 hours. However, only a few spot-like thrombi are formed on the surface of the fiber membrane that is coated after UV pretreatment 6 hours after contact with blood, indicating that the heparin coating formed after UV pretreatment has the best anticoagulant effect and has better anticoagulant performance.

[0105] (5) Uniformity and coverage of directional heparin coating (Example 1).

[0106] The results are as follows Figure 7 As shown, from the staining results, it can be seen that compared with the unidirectional coating (Comparative Example 2), the coating direction is changed midway, which increases the coverage of heparin, makes the heparin coating more uniform, and can improve the hydrophilicity and anticoagulant properties of the heparin coating.

[0107] (6) Uniformity and coverage of heparin coatings applied at different flow rates (Examples 1 and 3).

[0108] The results are as follows Figure 8 As shown, from the staining results, it can be seen that compared with the flow rate of 1 LPM, the uniformity and coverage of the heparin coating are significantly improved when the flow rate of 0.3 LPM is used for coating.

[0109] (7) Heparin coating uniformity and coverage at different coating times (Examples 2 and 4).

[0110] The results are as follows Fig. 9 As shown in the figure, the staining results show that compared with the coating for 1 h (circulation flushing and reverse flushing for 0.5 h each), the heparin coating coated for 4 h (circulation flushing and reverse flushing for 2 h each) is significantly more uniform and has a higher heparin coverage.

[0111] (8) Heparin coating uniformity and coverage of heparin solutions with different concentrations (Examples 1 and 5).

[0112] The results are as follows Fig.10 As shown, from the staining results, it can be seen that compared with 0.03% heparin solution, heparin is more evenly attached to the material surface when coated with a heparin solution with a mass concentration of 0.3%.

[0113] (9) Uniformity and coverage of heparin coating fixed with EDC solutions of different concentrations (Examples 2 and 6).

[0114] The results are as follows Fig.11 As shown, the staining results show that when the heparin coating is fixed with 0.03‰ EDC solution, the uniformity and coverage of the heparin coating are increased compared with that with 0.001‰ EDC solution.

[0115] Table 1 Performance test results of various embodiments

[0116] The present invention utilizes plasma-ultraviolet light or ultraviolet-ozone technology to stimulate the generation of free radicals or oxygen-containing groups on the surface of the PMP hollow fiber membrane, thereby inducing PEI to generate graft chains on its surface, thereby improving the hydrophilicity of the PMP hollow fiber membrane, enhancing the surface adhesion, and introducing amino functional groups to promote the adhesion and binding of heparin on its surface. The heparin coating prepared by the present invention through ultraviolet pretreatment combined with heparin directional coating is more uniform, has better hydrophilicity and anticoagulant properties, and has great application potential.

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a composite heparin anticoagulant coating, characterized in that: include: 1) UV pretreatment: UV pretreatment of the substrate material to initiate grafting of polyethyleneimine (PEI) onto the surface of the material; 2) Directional coating: a heparin solution is used to coat the surface of the substrate material and an EDC solution is used to fix the substrate; the coating direction is changed in the middle of the coating process.

2. The method for preparing the composite heparin anticoagulant coating according to claim 1, characterized in that: Use heparin solution for circulatory flushing at room temperature for 1-4 hours, then change the circulation direction and continue to circulate for 1-4 hours; and / or, use EDC solution for circulatory flushing at room temperature for 0.5-2 hours, then change the circulation direction and continue to circulate for 0.5-2 hours.

3. The method for preparing the composite heparin anticoagulant coating according to claim 2, characterized in that: The flow rate of circulating flushing with heparin solution and / or EDC solution is 0.05-0.5 LPM.

4. The method for preparing the composite heparin anticoagulant coating according to any one of claims 1 to 3, characterized in that: The mass fraction of the heparin solution is 0.05%-0.3%, and the pH is 2-5; and / or the mass fraction of the EDC solution is 0.002‰-0.03‰, and the pH is 2-6.

5. The method for preparing the composite heparin anticoagulant coating according to claim 4, characterized in that: The solvent of the heparin solution and / or the EDC solution is disodium hydrogen phosphate-citric acid buffer solution.

6. The method for preparing the composite heparin anticoagulant coating according to claim 1, characterized in that: The ultraviolet light pretreatment in step 1) includes plasma-ultraviolet pretreatment or ultraviolet-ozone pretreatment.

7. The method for preparing the composite heparin anticoagulant coating according to claim 6, characterized in that: The plasma-ultraviolet pretreatment comprises: 1) placing the substrate material in an argon plasma environment for treatment; 2) treating the treated substrate material in an environment containing O2; 3) Mix the PEI solution with the substrate material and react under UV irradiation.

8. The method for preparing the composite heparin anticoagulant coating according to claim 6, characterized in that: The ultraviolet-ozone pretreatment comprises: 1) Place the substrate material under a low-pressure mercury vapor lamp for activation treatment; 2) Mix the PEI solution with the substrate material and react under UV irradiation.

9. The method for preparing the composite heparin anticoagulant coating according to claim 1, characterized in that: The substrate material is a PMP hollow fiber membrane.

10. The composite heparin anticoagulant coating prepared by the preparation method according to any one of claims 1 to 9.

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