阅读说明：本技术 一种用于降低眼内压的肝素涂层引流管及其制备方法 (Heparin coating drainage tube for reducing intraocular pressure and preparation method thereof ) 是由 赵雪莹 范忠鹏 吴亮亮 刘静 蔡湫亭 马毓飞 于 2021-08-26 设计创作，主要内容包括：本发明属于眼科医用生物材料技术领域,提供一种用于降低眼内压的肝素涂层引流管及其制备方法,引流管包括生物高分子引流管基底以及在基底表面共价接枝的肝素涂层,其适用于微创植入,不仅生物相容性好、安全性高,而且具有良好的柔韧性和顺应性,并且其表面的肝素涂层能够有效的防止组织液或血液在其表面形成瘢痕或血栓,进一步降低手术可能出现的并发症。(The invention belongs to the technical field of ophthalmic medical biomaterials, and provides a heparin coating drainage tube for reducing intraocular pressure and a preparation method thereof.)

1. A heparin coated drainage tube for lowering intraocular pressure, characterized by: the heparin coating is formed by covalently grafting heparin on the surface of the substrate through a grafting technology.

2. Heparin coated drain for lowering intraocular pressure according to claim 1, characterized in that: the inner diameter of the drainage tube is 20-150 mu m, the outer diameter is 100-500 mu m, and the length of the drainage tube is 2-12 mm.

3. A preparation method of a heparin coating drainage tube for reducing intraocular pressure is characterized in that: the method comprises the following steps:

s1: preparing a drainage tube substrate:

s1.1: hydrophilic treatment of the metal wire: after the surface of the metal wire is treated by plasma, the metal wire is immersed into 10 percent (w/w) of water-soluble polymer solution for 30 minutes and then dried to obtain the hydrophilic metal wire;

s1.2: preparing 10% -20% -40% (w/w) gradient concentration biopolymer solution: dissolving biopolymer powder in sterile injection water, respectively preparing three solutions with the concentrations of 10% (w/w), 20% (w/w) and 40% (w/w), and preserving heat at 50-60 ℃ for later use;

s1.3: preparing a cross-linking fixing solution: preparing a cross-linking agent into a fixing solution with the concentration of 1% (w/w) for later use;

s1.4: sequentially carrying out cross-linking solidification on the hydrophilic metal wire in the step S1.1 by using 10-20-40% (w/w) gradient concentration biopolymer solution in the step S1.2 and then by using cross-linking fixing solution in the step S1.3 to finish a cycle operation; repeating the cycle operation for 1-100 times, and then drying and drawing off the metal wire to obtain a biopolymer drainage tube substrate;

wherein, the sequence of the steps S1.1-S1.3 includes but is not limited to the sequence;

s2: preparing a heparin coating on the surface of a drainage tube substrate:

s2.1: preparing a grafting agent solution containing a hydrazide group;

s2.2: preparing an aldehyde heparin solution;

s2.3: soaking the drainage tube substrate obtained in the step S1.4 in a crosslinking fixing solution again for sufficient crosslinking activation for 1-12 h to obtain a surface activated biopolymer drainage tube substrate;

s2.4: soaking the surface-activated biopolymer drainage tube substrate obtained in the step S2.3 in the grafting agent solution containing the hydrazide groups prepared in the step S2.1 to react for 1-12 h to obtain a drainage tube with the surface grafted with the grafting agent containing the hydrazide groups;

s2.5: soaking the drainage tube grafted with the hydrazide group-containing grafting agent on the surface obtained in the step S2.4 in the aldehyde heparin solution prepared in the step S2.2 for reaction for 1-12 h to obtain the drainage tube grafted with heparin on the surface;

wherein, the sequence of preparing the two solutions in the steps S2.1 and S2.2 includes but is not limited to the sequence;

s3: cleaning and drying

And (5) cleaning and drying the drainage tube with the surface grafted with the heparin obtained in the step (S2.5) to finally obtain the heparin coating drainage tube.

4. A method of making a heparin coated drain for reducing intraocular pressure as claimed in claim 3, wherein: in the preparation step S1.1, the metal wire is a stainless steel wire or a nickel-titanium wire, and the diameter of the metal wire is 20-150 mu m.

5. A method of making a heparin coated drain for reducing intraocular pressure as claimed in claim 4, wherein: the water-soluble polymer of the water-soluble polymer solution in the preparation step S1.1 is one of sodium polystyrene sulfonate, polyoxyethylene, polyvinylpyrrolidone and polyvinyl alcohol.

6. A method of making a heparin coated drain for reducing intraocular pressure as claimed in claim 4, wherein: the biopolymer of the gradient concentration biopolymer solution in the preparation step S1.2 is one of chitosan or its derivative, sodium hyaluronate or its derivative, sodium alginate or its derivative, gelatin, silk fibroin, cellulose and its derivative.

7. A method of making a heparin coated drain for reducing intraocular pressure as claimed in claim 4, wherein: the cross-linking agent for cross-linking the stationary liquid in the preparation step S1.3 is one of 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide, 4- (4, 6-dimethoxytriazine-2-yl) -4-methylmorpholine hydrochloride, crotonaldehyde, glutaraldehyde and calcium chloride.

8. A method of making a heparin coated drain for reducing intraocular pressure as claimed in claim 4, wherein: the grafting agent for preparing the grafting agent solution containing the hydrazide groups in the step S2.1 is one of dihydrazide, polyhydrazide, hydrazide group-modified biomacromolecules and hydrazide group-modified artificially synthesized polymers;

wherein the dihydrazide is one of adipic acid dihydrazide, oxalic acid dihydrazide, succinic acid dihydrazide, malonic acid dihydrazide, ethyl malonic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, maleic acid dihydrazide, pimelic acid dihydrazide and dithiodipropylhydrazide;

the biomacromolecule modified by the hydrazide group is one of chitosan modified by the hydrazide group, sodium hyaluronate modified by the hydrazide group, sodium alginate modified by the hydrazide group, gelatin modified by the hydrazide group, silk fibroin modified by the hydrazide group and cellulose modified by the hydrazide group.

The hydrazide group modified artificially synthesized polymer is one of hydrazide group modified polyether, hydrazide group modified polyester, hydrazide group modified polyurethane, hydrazide group modified polyurea and hydrazide group modified polyacrylate.

9. A method of making a heparin coated drain for reducing intraocular pressure as claimed in claim 4, wherein: the concentration of the grafting agent solution containing the hydrazide groups in the preparation step S2.1 is 0.01-20% (w/w), and the solvent is one of water, dimethyl sulfoxide, N-dimethylformamide and N, N-dimethylacetamide or a mixed solvent consisting of at least two of the components according to different proportions.

10. A method of making a heparin coated drain for reducing intraocular pressure as claimed in claim 4, wherein: the aldehyde-based heparin in the aldehyde-based heparin solution in the preparation step S2.2 is heparin or heparin derivatives which are chemically modified to make the molecular structure of the heparin molecules contain aldehyde groups, and the chemical modification method is sodium nitrite oxidation or sodium periodate oxidation.

11. A method of making a heparin coated drain for reducing intraocular pressure as claimed in claim 4, wherein: the concentration of the aldehyde heparin solution in the preparation step S2.2 is 0.01-20% (w/w), and the solvent is one of water, methanol, ethanol, isopropanol, tetrahydrofuran, dimethyl sulfoxide, N-dimethylformamide and N, N-dimethylacetamide or a mixed solvent of at least two of the components in different proportions.

Technical Field

The invention relates to the technical field of ophthalmic medical biomaterials, in particular to a heparin coating drainage tube for reducing intraocular pressure and a preparation method thereof.

Background

Glaucoma is an irreversible blinding eye disease characterized by damage to the optic papilla, loss of vision and associated visual field defects, the main factors responsible for the pathogenesis being pathological elevated intraocular pressure and insufficient blood supply to the optic nerve, but the factors that induce glaucoma are complex. The main clinical treatment method at present is intraocular pressure reduction, intraocular pressure reduction treatment of early glaucoma is mainly performed by adopting a medicament mode, but drug resistance can be generated by long-term administration of patients, most of patients are in the middle and late stages at the time of treatment, and the requirement of medicament treatment cannot be met, so that operation is needed for treatment. Currently, the clinical surgical treatment mode still uses a Glaucoma Filtration Surgery (GFS) as a main surgical mode to establish an aqueous humor drainage channel so as to achieve the effect of reducing intraocular pressure. In the filtration surgery, trabeculectomy is still the main diagnosis and treatment means for controlling the progress of glaucoma in China at the present stage, however, various complications such as early superficial anterior chamber, hemangiocele, filtration bleb wrapping, choroidal detachment or delayed choroidal hemorrhage exist for a long time after the surgery, and fibrosis and scarring of the filtration bleb further cause the failure of the surgery.

With the continuous progress of medical science and technology in recent years, minimally invasive technology has been gradually applied to the treatment of glaucoma disease. Compared with the conventional treatment method, the minimally invasive surgery has the advantages of small wound area, short recovery period of patients and obvious reduction of adverse reactions and complications. The glaucoma drainage tube present therein has received a wide attention. The drainage tube is very small in size, and is delivered to a proper position in a minimally invasive mode through a delivery device to guide aqueous humor out of the anterior chamber so as to achieve the function of reducing intraocular pressure. Chinese patent CN 107811752A discloses a micro-chitosan glaucoma drainage tube, the inner diameter is 300-700 μm, the outer diameter is 400-950 μm, the micro-chitosan glaucoma drainage tube is prepared by a template-solidification method, the process is simple, and the cost is low. Nevertheless, the chitosan material itself has positive charge, and when implanted into eyes and contacted with tissues or blood, the chitosan material is easy to cause reactions such as allergy, inflammation and blood coagulation; chinese patent CN 110524769A discloses a micron-sized glaucoma drainage tube, the inner diameter is 100-500 μm, the outer diameter is 300-1000 μm, gelatin or derivatives thereof are used as a matrix, and the micron-sized glaucoma drainage tube is finally prepared by steps of curing, crosslinking, drying and the like through a self-made gel tube preparation device, and has good biocompatibility and controllable performance; however, it has been shown that gelatin can promote the aggregation of platelets, increase the release of platelet active factors PF4, P-selectin and TXB2, stimulate the intrinsic coagulation pathway and thus play a role in rapid hemostasis, so the glaucoma drainage tube using gelatin as a matrix still cannot avoid the coagulation reaction generated when contacting the intraocular tissue or blood; chinese patent CN 111467581A discloses an acrylic acid ester glaucoma drainage tube, the inner diameter is 35-75 μm, the outer diameter is 300-400 μm, the drainage tube is obtained by lifting and dipping in sol-gel liquid through a lifting wire, and the steps of crosslinking, curing, impurity removal, drying, demolding and the like are carried out, so that the drainage tube has good flexibility and compliance, however, toxic small molecules such as a free radical initiator, a crosslinking agent and the like used in the preparation process cannot be completely removed, the safety risk still exists when the drainage tube is applied to a human body for a long time, and inflammation, blood coagulation and the like caused when the drainage tube is contacted with tissues or blood in the human body cannot be avoided. In this regard, none of these patents teach how to address or reduce adverse reactions such as allergy, inflammation or coagulation or other complications caused thereby that may occur when a glaucoma drainage tube is implanted in an eye in contact with tissue or blood.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: in order to overcome the defects in the prior art, the invention provides a heparin coating drainage tube for reducing intraocular pressure and a preparation method thereof.

The technical scheme adopted for solving the technical problems is as follows: a heparin coated drainage tube for reducing intraocular pressure comprises a substrate and a heparin coating, wherein the substrate is made of a biopolymer material, and the heparin coating is formed by covalently grafting heparin on the surface of the substrate through a grafting technology.

Furthermore, the inner diameter of the drainage tube is 20-150 μm, the outer diameter is 100-500 μm, and the length of the drainage tube is 2-12 mm. Preferably, the inner diameter of the drainage tube is 50-80 μm, the outer diameter is 120-250 μm, and the length of the drainage tube is 3-8 mm.

A preparation method of a heparin coated drainage tube for reducing intraocular pressure comprises the following steps:

s1: preparing a drainage tube substrate:

s1.1: hydrophilic treatment of the metal wire: after the surface of the metal wire is treated by plasma, the metal wire is immersed into 10 percent (w/w) of water-soluble polymer solution for 30 minutes and then dried to obtain the hydrophilic metal wire;

s1.2: preparing 10% -20% -40% (w/w) gradient concentration biopolymer solution: dissolving biopolymer powder in sterile injection water, respectively preparing three solutions with the concentrations of 10% (w/w), 20% (w/w) and 40% (w/w), and preserving heat at 50-60 ℃ for later use;

s1.3: preparing a cross-linking fixing solution: preparing a cross-linking agent into a fixing solution with the concentration of 1% (w/w) for later use;

s1.4: sequentially carrying out cross-linking solidification on the hydrophilic metal wire in the step S1.1 by using 10-20-40% (w/w) gradient concentration biopolymer solution in the step S1.2 and then by using cross-linking fixing solution in the step S1.3 to finish a cycle operation; repeating the cycle operation for 1-100 times, and then drying and drawing off the metal wire to obtain a biopolymer drainage tube substrate;

wherein, the sequence of the steps S1.1-S1.3 includes but is not limited to the sequence;

s2: preparing a heparin coating on the surface of a drainage tube substrate:

s2.1: preparing a grafting agent solution containing a hydrazide group;

s2.2: preparing an aldehyde heparin solution;

s2.3: soaking the drainage tube substrate obtained in the step S1.4 in a crosslinking fixing solution again for sufficient crosslinking activation for 1-12 h to obtain a surface activated biopolymer drainage tube substrate;

s2.4: soaking the surface-activated biopolymer drainage tube substrate obtained in the step S2.3 in the grafting agent solution containing the hydrazide groups prepared in the step S2.1 to react for 1-12 h to obtain a drainage tube with the surface grafted with the grafting agent containing the hydrazide groups;

s2.5: soaking the drainage tube grafted with the hydrazide group-containing grafting agent on the surface obtained in the step S2.4 in the aldehyde heparin solution prepared in the step S2.2 for reaction for 1-12 h to obtain the drainage tube grafted with heparin on the surface;

wherein, the sequence of preparing the two solutions in the steps S2.1 and S2.2 includes but is not limited to the sequence;

s3: cleaning and drying

And (5) cleaning and drying the drainage tube with the surface grafted with the heparin obtained in the step (S2.5) to finally obtain the heparin coating drainage tube.

Specifically, the metal wire in the preparation step S1.1 is a stainless steel wire or a nickel-titanium wire, and the diameter of the metal wire is 20-150 μm, preferably 40-100 μm.

Specifically, the water-soluble polymer of the water-soluble polymer solution in the preparation step S1.1 is one of sodium polystyrene sulfonate (PSS), polyethylene oxide (PEO), polyvinylpyrrolidone (PVP), and polyvinyl alcohol (PVA).

Preferably, the water-soluble polymer is polyethylene oxide (PEO) or polyvinylpyrrolidone (PVP).

More preferably, the water-soluble polymer is polyvinylpyrrolidone (PVP).

Specifically, the biopolymer of the gradient concentration biopolymer solution in the preparation step S1.2 is one of chitosan or its derivative, sodium hyaluronate or its derivative, sodium alginate or its derivative, gelatin, silk fibroin, cellulose and its derivative.

Preferably, the biopolymer of the gradient biopolymer solution in the preparation step S1.2 is one of chitosan or its derivative, gelatin, sodium alginate or its derivative.

Further preferably, the biopolymer of the biopolymer solution with gradient concentration in the preparation step S1.2 is gelatin.

Specifically, the crosslinking agent for preparing the crosslinking fixing solution in the step S1.3 is one of 1- (3-dimethylaminopropyl) -3-Ethylcarbodiimide (EDC), 4- (4, 6-dimethoxytriazin-2-yl) -4-methylmorpholine hydrochloride (DMTMM), crotonaldehyde, glutaraldehyde and calcium chloride.

Preferably, the cross-linking agent for preparing the cross-linked fixative in step S1.3 is glutaraldehyde.

Specifically, the grafting agent of the grafting agent solution containing the hydrazide group in the step S2.1 is one of dihydrazide, polyhydrazide, hydrazide group-modified biomacromolecule, and hydrazide group-modified artificially synthesized polymer.

Wherein the dihydrazide is one of adipic acid dihydrazide, oxalic acid dihydrazide, succinic acid dihydrazide, malonic acid dihydrazide, ethyl malonic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, maleic acid dihydrazide, pimelic acid dihydrazide and dithiodipropylhydrazide.

The biomacromolecule modified by the hydrazide group is one of chitosan modified by the hydrazide group, sodium hyaluronate modified by the hydrazide group, sodium alginate modified by the hydrazide group, gelatin modified by the hydrazide group, silk fibroin modified by the hydrazide group and cellulose modified by the hydrazide group.

The hydrazide group modified artificially synthesized polymer is one of hydrazide group modified polyether, hydrazide group modified polyester, hydrazide group modified polyurethane, hydrazide group modified polyurea and hydrazide group modified polyacrylate.

Specifically, the concentration of the grafting agent solution containing the hydrazide group in the preparation step S2.1 is 0.01-20% (w/w), and the solvent is one of water, dimethyl sulfoxide, N-dimethylformamide and N, N-dimethylacetamide or a mixed solvent of at least two of the above components in different proportions.

Specifically, the aldehyde heparin in the preparation step S2.2 is heparin or heparin derivatives, which are chemically modified to have aldehyde groups in their molecular structures. Wherein, the chemical modification method is sodium nitrite oxidation or sodium periodate oxidation.

Specifically, the concentration of the aldehyde heparin solution in the preparation step S2.2 is 0.01-20% (w/w), and the solvent is one of water, methanol, ethanol, isopropanol, tetrahydrofuran, dimethyl sulfoxide, N-dimethylformamide and N, N-dimethylacetamide or a mixed solvent of at least two of the above components in different proportions.

The invention has the beneficial effects that: the heparin coating drainage tube for reducing the intraocular pressure and the preparation method thereof are suitable for minimally invasive implantation, have good biocompatibility and high safety, and have good flexibility and compliance, and the heparin coating on the surface of the drainage tube can effectively prevent tissue fluid or blood from forming scars or thrombus on the surface of the drainage tube, thereby further reducing the possible complications of the operation.

Drawings

The invention is further illustrated by the following figures and examples.

FIG. 1 is a graph comparing the change in hydrophilicity before and after coating.

FIG. 2 is a comparison of the dyeing before and after coating.

Figure 3 is a standard curve of heparin sodium.

Figure 4 is a stability curve of the coating in BSS buffer.

Detailed Description

The present invention will now be described in detail with reference to the accompanying drawings.

The invention discloses a heparin coating drainage tube for reducing intraocular pressure, which comprises a substrate and a heparin coating, wherein the substrate is made of a biopolymer material, and the heparin coating is formed by covalently grafting heparin on the surface of the substrate through a grafting technology. The inner diameter of the drainage tube is 20-150 mu m, the outer diameter is 100-500 mu m, and the length of the drainage tube is 2-12 mm. Preferably, the inner diameter of the drainage tube is 50-80 μm, the outer diameter is 120-250 μm, and the length of the drainage tube is 3-8 mm.

The invention discloses a preparation method of a heparin coating drainage tube for reducing intraocular pressure, which is used for preparing the drainage tube and comprises the following steps:

s1: preparing a drainage tube substrate:

s1.1: hydrophilic treatment of the metal wire: the hydrophilic metal wire is obtained by immersing the metal wire after plasma surface treatment in a 10% (w/w) water-soluble polymer solution for 30 minutes and then drying. Wherein the metal wire is a stainless steel wire or a nickel titanium wire, and the diameter of the metal wire is 20-150 μm, preferably 40-100 μm. The water-soluble polymer of the water-soluble polymer solution is one of sodium polystyrene sulfonate (PSS), polyethylene oxide (PEO), polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA); preferably, the water-soluble polymer is polyethylene oxide (PEO) or polyvinylpyrrolidone (PVP); more preferably, the water-soluble polymer is polyvinylpyrrolidone (PVP).

S1.2: preparing 10% -20% -40% (w/w) gradient concentration biopolymer solution: dissolving the biopolymer powder in sterile injection water, respectively preparing three solutions with the concentrations of 10% (w/w), 20% (w/w) and 40% (w/w), and preserving heat at 50-60 ℃ for later use. Wherein, the biological macromolecule for preparing the biological macromolecule solution with gradient concentration is one of chitosan or derivatives thereof, sodium hyaluronate or derivatives thereof, sodium alginate or derivatives thereof, gelatin, silk fibroin, cellulose and derivatives thereof; preferably, the biological macromolecule is one of chitosan or derivatives thereof, gelatin, sodium alginate or derivatives thereof; more preferably, the biopolymer is gelatin.

S1.3: preparing a cross-linking fixing solution: the cross-linking agent is prepared into a fixing solution with the concentration of 1% (w/w) for standby. Wherein the crosslinking agent for preparing the crosslinking stationary liquid is one of 1- (3-dimethylaminopropyl) -3-Ethylcarbodiimide (EDC), 4- (4, 6-dimethoxytriazine-2-yl) -4-methylmorpholine hydrochloride (DMTMM), crotonaldehyde, glutaraldehyde and calcium chloride; preferably, the cross-linking agent is glutaraldehyde.

S1.4: sequentially carrying out cross-linking solidification on the hydrophilic metal wire in the step S1.1 by using 10-20-40% (w/w) gradient concentration biopolymer solution in the step S1.2 and then by using cross-linking fixing solution in the step S1.3 to finish a cycle operation; and repeating the cycle operation for 1-100 times, and then drying and drawing off the metal wire to obtain the biopolymer drainage tube substrate.

Wherein, the sequence of the steps S1.1-S1.3 includes but is not limited to the sequence;

s2: preparing a heparin coating on the surface of a drainage tube substrate:

s2.1: preparing a grafting agent solution containing a hydrazide group. Specifically, the grafting agent for preparing the grafting agent solution containing the hydrazide groups is one of dihydrazide, polyhydrazide, hydrazide group modified biomacromolecules and hydrazide group modified artificially synthesized polymers. Wherein the dihydrazide is one of adipic acid dihydrazide, oxalic acid dihydrazide, succinic acid dihydrazide, malonic acid dihydrazide, ethyl malonic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, maleic acid dihydrazide, pimelic acid dihydrazide and dithiodipropylhydrazide. The biomacromolecule modified by the hydrazide group is one of chitosan modified by the hydrazide group, sodium hyaluronate modified by the hydrazide group, sodium alginate modified by the hydrazide group, gelatin modified by the hydrazide group, silk fibroin modified by the hydrazide group and cellulose modified by the hydrazide group. The hydrazide group modified artificially synthesized polymer is one of hydrazide group modified polyether, hydrazide group modified polyester, hydrazide group modified polyurethane, hydrazide group modified polyurea and hydrazide group modified polyacrylate. The concentration of the grafting agent solution is 0.01-20% (w/w), and the solvent is one of water, dimethyl sulfoxide, N-dimethylformamide and N, N-dimethylacetamide or a mixed solvent of at least two of the components in different proportions.

S2.2: preparing aldehyde heparin solution. Specifically, the aldehyde heparin for preparing the aldehyde heparin solution is heparin molecules of which the molecular structures contain aldehyde groups due to chemical modification of heparin or heparin derivatives. Wherein, the chemical modification method is sodium nitrite oxidation or sodium periodate oxidation. The concentration of the aldehyde heparin solution is 0.01-20% (w/w), and the solvent is one of water, methanol, ethanol, isopropanol, tetrahydrofuran, dimethyl sulfoxide, N-dimethylformamide and N, N-dimethylacetamide or a mixed solvent of at least two of the components in different proportions.

S2.3: and (5) soaking the drainage tube substrate obtained in the step (S1.4) in a crosslinking fixing solution again for sufficient crosslinking activation for 1-12 h to obtain a surface activated biopolymer drainage tube substrate.

S2.4: and (3) soaking the surface-activated biopolymer drainage tube substrate obtained in the step (S2.3) in the grafting agent solution containing the hydrazide groups obtained in the step (S2.1) to react for 1-12 h, so as to obtain the drainage tube with the surface grafted with the grafting agent containing the hydrazide groups.

S2.5: and (3) soaking the drainage tube grafted with the hydrazide group-containing grafting agent on the surface obtained in the step (S2.4) in the aldehyde heparin solution prepared in the step (S2.2) for reaction for 1-12 h to obtain the drainage tube grafted with heparin on the surface.

Wherein, the sequence of preparing the two solutions in steps S2.1 and S2.2 includes, but is not limited to, the above sequence.

S3: cleaning and drying:

and (5) cleaning and drying the drainage tube with the surface grafted with the heparin obtained in the step (S2.5) to finally obtain the heparin coating drainage tube.

The following sets of specific data are used to specifically illustrate the preparation method and the test results.

An exemplary embodiment is as follows:

1: preparation of heparin coating drainage tube

S1: preparing a drainage tube substrate:

s1.1: hydrophilic treatment of the metal wire: selecting a nickel-titanium wire with the diameter of 60 mu m, performing plasma surface treatment, immersing the wire into a 10% (w/w) polyvinylpyrrolidone solution for 30 minutes, and then drying to obtain a hydrophilic metal wire;

s1.2: preparing 10% -20% -40% (w/w) gelatin solution with gradient concentration: dissolving gelatin powder in sterile injection water, preparing three solutions with the concentrations of 10% (w/w), 20% (w/w) and 40% (w/w) respectively, and preserving heat at 50-60 ℃ for later use;

s1.3: preparing glutaraldehyde crosslinking stationary liquid: preparing a glutaraldehyde crosslinking agent into a fixing solution with the concentration of 1% (w/w) for later use;

s1.4: sequentially passing the hydrophilic nickel-titanium wires through 10-20-40% (w/w) gradient concentration gelatin solution in the step S1.2, and then performing crosslinking and curing through glutaraldehyde crosslinking fixing solution in the step S1.3 to complete a cycle operation; repeating the cycle operation for 30 times, and then drying and drawing out the nickel-titanium wires to obtain the gelatin drainage tube substrate;

s2: preparing a heparin coating on the surface of the gelatin drainage tube substrate:

s2.1: preparing 10% (w/w) adipic dihydrazide grafting agent solution: dissolving 10g of adipic acid dihydrazide solution in sterile injection water to prepare a grafting agent solution with the concentration of 10% (w/w);

s2.2: preparing 1% (w/w) of aldehyde heparin solution: dissolving 1g of aldehyde heparin oxidized by sodium nitrite in sterile injection water to prepare 1% (w/w) aldehyde heparin solution;

s2.3: soaking the gelatin drainage tube substrate obtained in the step S1.4 in glutaraldehyde fixing solution with the concentration of 1% (w/w) again for sufficient crosslinking and activation for 12h to obtain a gelatin drainage tube with activated surface aldehyde groups;

s2.4: soaking the gelatin drainage tube substrate with activated surface aldehyde groups obtained in the step S2.3 in 10% (w/w) adipic dihydrazide grafting agent solution for reaction for 1h to obtain the gelatin drainage tube with activated surface hydrazide groups;

s2.5: soaking the gelatin drainage tube with the surface hydrazide group activated obtained in the step S2.4 in 1% (w/w) aldehyde heparin solution for reaction for 12h to obtain the gelatin drainage tube with the surface grafted with heparin;

s3: cleaning and drying: and (5) cleaning and drying the gelatin drainage tube with the surface grafted with the heparin obtained in the step (S2.5) to finally obtain the heparin coating drainage tube.

2: testing the surface hydrophilicity change (contact angle test) of the prepared heparin coated drainage tube:

the heparin coating caused a change in surface hydrophilicity, but since the drainage tube size was very small, it was difficult to perform contact angle measurements, etc., and therefore, to investigate the hydrophilicity of the drainage tube surfaces before and after coating, the drainage tube was replaced with a gelatin sheet (1 cm x 0.1 cm), and water contact angle measurements were performed on the gelatin sheet samples before and after coating.

The test process is as follows: and (3) dropwise adding 20 mu L of purified water on the surface of the sample, respectively shooting the contact section of the water and the surface of the sample at 0s, 10s, 20s, 30s, 40s, 50s and 60s after dropwise adding, obtaining water contact angle data of 7 different time points, and calculating the average contact angle of the water contact angle data through software fitting. As shown in fig. 1, the water contact angle after coating was significantly reduced compared to the water contact angle before coating, thus confirming successful preparation of the heparin coating and improved hydrophilicity after coating.

3. Testing the distribution uniformity of the heparin on the surface of the prepared heparin coating drainage tube:

sulfonic groups in heparin molecules can form a purple complex with Toluidine Blue (TBO) dye, so the heparin distribution on the surface of the substrate is detected by the following method:

a. preparing toluidine blue solution (0.01M HCl, 0.2wt% NaCl, 0.001wt% TBO);

b. and soaking the sample to be tested (before and after coating) in toluidine blue solution for reaction, then taking out, washing with purified water, drying, and photographing to observe the surface color of the substrate. As shown in fig. 2, the left side is a staining pattern before coating, the color is not changed basically, the right side is a staining pattern after coating, the color is purple red, which indicates that the heparin coating is prepared successfully, and the right side is stained uniformly, so that the heparin coating can be judged to be distributed more uniformly.

4. Testing the durability of the prepared heparin coating drainage tube:

sulfonic acid groups in heparin molecules can form purple complexes with Toluidine Blue (TBO) dye, the complexes have characteristic absorption at 623nm, so the heparin content in coated heparin can be measured by uv-vis spectrophotometry, and gelatin sheets (1 cm x 0.1 cm) are used instead of drainage tubes, and the test method is as follows:

a. preparing toluidine blue solution (0.01M HCl, 0.2wt% NaCl, 0.001wt% TBO);

b. mixing and oscillating 2.5mL of standard heparin sodium solution with known content and 2.5mL of freshly prepared toluidine blue solution for 30 s;

c. n-hexane was added to the above test tube, and the mixture was sufficiently shaken for 30 seconds. Taking an organic phase, measuring the absorbance at the wavelength of 623nm by using a spectrophotometer, and drawing an absorbance-heparin sodium content standard curve as shown in figure 3;

d. immersing samples to be tested (gelatin sheets before and after coating) into 5mL of BSS buffer solution, eluting and oscillating for 0 day, 1 day, 2 days, 4 days, 7 days, 15 days and 30 days at 37 ℃, taking out, then immersing in 2.5mL of freshly prepared toluidine blue solution, diluting to 5mL, slightly oscillating for 4h at room temperature, and taking out the samples; the absorbance of the liquid was measured at a wavelength of 623nm and calculated with reference to the standard curve shown in FIG. 3. The results are shown in fig. 4, which shows that the coating is stable in BSS buffer solution, and the density of the heparin coating is not changed greatly from 0 to 30 days, which indicates that the heparin coating is combined stably and firmly.

In light of the foregoing description of preferred embodiments in accordance with the invention, it is to be understood that numerous changes and modifications may be made by those skilled in the art without departing from the scope of the invention. The technical scope of the present invention is not limited to the contents of the specification, and must be determined according to the scope of the claims.