阅读说明：本技术 一种胆道支架及其制备方法 (Biliary tract stent and preparation method thereof ) 是由 肖瑶 姚磊 赵杰 谭玉勇 于 2021-09-06 设计创作，主要内容包括：一种胆道支架及其制备方法,为了提高胆道支架的抗菌性能,降低胆道支架阻塞的风险,本发明在传统的胆道支架表面制备了聚乳酸/三氯生涂覆层,通过抗菌剂三氯生可以赋予胆道支架优异的抗菌能力,避免细菌与蛋白类物质附着于支架表面。深入研究后发现,抗菌剂添加量过多会导致胆道支架的生物相容性下降,进一步的,本发明在聚乳酸/三氯生涂覆层中添加了少量的石墨烯,如此,可以将胆道支架材料的溶血率降低到令人满意的水平。值得一提的是,石墨烯的添加量并非越高越好,过多的石墨烯会导致胆道支架的生物相容性进一步恶化。(In order to improve the antibacterial performance of the biliary tract stent and reduce the risk of biliary tract stent blockage, the invention prepares a polylactic acid/triclosan coating layer on the surface of the traditional biliary tract stent, and the antibacterial agent triclosan can endow the biliary tract stent with excellent antibacterial ability to prevent bacteria and protein substances from being attached to the surface of the stent. After intensive research, the inventor finds that the biocompatibility of the biliary tract stent is reduced due to the excessive addition of the antibacterial agent, and further, the invention adds a small amount of graphene in the polylactic acid/triclosan coating layer, so that the hemolysis rate of the biliary tract stent material can be reduced to a satisfactory level. It is worth mentioning that the higher the addition amount of graphene is, the better the addition amount is, and the excessive graphene may further deteriorate the biocompatibility of the biliary tract stent.)

1. The preparation method of the biliary tract stent is characterized by comprising the following steps:

A. pretreatment of a base material: sequentially polishing, grinding, deoiling, cleaning and drying the biliary tract stent material for later use, wherein sodium bicarbonate solution is selected for deoiling, deionized water is selected for cleaning and is matched with ultrasonic wave for assistance, and drying is carried out under the condition of nitrogen;

B. preparation of coating layer solution: weighing polylactic acid, adding the polylactic acid into an ethyl acetate solution, properly stirring to fully dissolve the polylactic acid, weighing triclosan, adding the triclosan into the polylactic acid solution, and uniformly stirring to obtain a coating layer solution;

C. preparing a coating layer: and (3) immersing the pretreated biliary tract stent material into the coating layer solution for 15-20min, taking out, airing, immersing again, repeating for 5-8 times, taking out, and drying in vacuum for 40-60h to obtain the biliary tract stent material containing the coating layer.

2. A method of making according to claim 1, wherein: the scaffold material was 1 x 1cm in size.

3. A method of making according to claim 1, wherein: the concentration of the sodium bicarbonate solution was 20%.

4. A method of making according to claim 1, wherein: the mass of the triclosan is 5-15% of that of the polylactic acid.

5. A method of making according to claim 1, wherein: the mass of the triclosan is 20-30% of that of the polylactic acid.

6. A method of preparing as defined in claim 5, wherein: the coating layer solution further includes a graphene dispersion.

7. A method of making according to claim 1, wherein: the graphene accounts for 1-5% of the mass of the polylactic acid.

8. A method of making according to claim 7, wherein: the graphene accounts for 3% of the mass of the polylactic acid.

9. A biliary stent, comprising: the biliary stent is prepared by any one of the methods of claims 1-8.

Technical Field

The invention relates to the field of biliary stents, in particular to a biliary stent and a preparation method thereof.

Background

Biliary obstruction, especially obstruction of common bile duct, is a common abnormality of biliary tract, and causes of biliary obstruction generally include calculi, inflammation, tumor, scars, and the like. The main clinical manifestations of biliary obstruction are right upper abdominal pain, fluctuating or progressive obstructive jaundice, and secondary biliary infection with chills and fever. If the biliary obstruction is not timely relieved, biliary tract infection is often caused, septicemia, biliary abscess, septic shock and multi-organ dysfunction are frequently caused, the disease condition is rapidly worsened, and the fatality rate is very high.

In clinical practice, the biliary stent implantation is a common interventional therapy method for solving the biliary obstruction. However, biliary stent occlusion is a common clinical problem, mainly due to the deposition of bacterial biofilm formed by viscous proteins and bacteria on the stent surface, and the accumulation of bacteria and products with calcium palmitate and calcium bilirubinate to form biliary mud. Therefore, it is an effective method to prepare a biliary stent having antibacterial properties to alleviate the occlusion. In view of this, how to prepare a biliary stent having excellent antibacterial properties is a long-standing problem in the medical field.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a preparation method of a biliary tract stent, which can improve the antibacterial performance of the biliary tract stent and has good biocompatibility.

The preparation method of the biliary tract stent is characterized by comprising the following steps:

A. pretreatment of a base material: sequentially polishing, grinding, deoiling, cleaning and drying the biliary tract stent material for later use, wherein sodium bicarbonate solution is selected for deoiling, deionized water is selected for cleaning and is matched with ultrasonic wave for assistance, and drying is carried out under the condition of nitrogen;

B. preparation of coating layer solution: weighing polylactic acid, adding the polylactic acid into an ethyl acetate solution, properly stirring to fully dissolve the polylactic acid, weighing triclosan, adding the triclosan into the polylactic acid solution, and uniformly stirring to obtain a coating layer solution;

C. preparing a coating layer: and (3) immersing the pretreated biliary tract stent material into the coating layer solution for 15-20min, taking out, airing, immersing again, repeating for 5-8 times, taking out, and drying in vacuum for 40-60h to obtain the biliary tract stent material containing the coating layer.

Further, the scaffold material has a size of 1 x 1 cm.

Further, the concentration of the sodium bicarbonate solution was 20%.

Further, the mass of the triclosan is 5-15% of the mass of the polylactic acid.

Further, the mass of the triclosan is 20-30% of the mass of the polylactic acid.

Further, the coating layer solution further includes a graphene dispersion.

Further, the graphene accounts for 1-5% of the mass of the polylactic acid.

Further, the graphene accounts for 3% of the mass of the polylactic acid.

Furthermore, the invention also provides a biliary tract stent prepared by the method.

In order to improve the antibacterial performance of the biliary tract stent and reduce the risk of blockage of the biliary tract stent, the invention prepares the polylactic acid/triclosan coating layer on the surface of the traditional biliary tract stent, and the antibacterial agent triclosan can endow the biliary tract stent with excellent antibacterial capability, thereby preventing bacteria and protein substances from being attached to the surface of the stent. After intensive research, the inventor finds that the biocompatibility of the biliary tract stent is reduced due to the excessive addition of the antibacterial agent, and further, the invention adds a small amount of graphene in the polylactic acid/triclosan coating layer, so that the hemolysis rate of the biliary tract stent material can be reduced to a satisfactory level. It is worth mentioning that the higher the addition amount of graphene is, the better the addition amount is, and the excessive graphene may further deteriorate the biocompatibility of the biliary tract stent.

Detailed Description

The technical effects of the present invention are demonstrated below by specific examples, but the embodiments of the present invention are not limited thereto.

Example 1

A. Pretreatment of a base material: cutting the biliary tract stent material into 1 × 1cm, polishing, grinding, removing oil, cleaning and drying for later use, wherein sodium bicarbonate solution with the concentration of 20% is selected for removing oil, deionized water is selected for cleaning and matched with ultrasonic wave for assistance, and drying is carried out under the condition of nitrogen;

B. preparation of coating layer solution: weighing 20g of polylactic acid, adding the polylactic acid into an ethyl acetate solution, properly stirring to fully dissolve the polylactic acid, weighing triclosan according to 5% of the mass of the polylactic acid, adding the triclosan into the polylactic acid solution, and uniformly stirring to obtain a coating layer solution;

C. preparing a coating layer: and (3) immersing the pretreated biliary tract stent material into the coating layer solution for 15min, taking out, airing, immersing again, repeating for 5 times, taking out, and drying in vacuum for 60h to obtain the biliary tract stent material containing the coating layer.

Example 2

A. Pretreatment of a base material: cutting the biliary tract stent material into 1 × 1cm, polishing, grinding, removing oil, cleaning and drying for later use, wherein sodium bicarbonate solution with the concentration of 20% is selected for removing oil, deionized water is selected for cleaning and matched with ultrasonic wave for assistance, and drying is carried out under the condition of nitrogen;

B. preparation of coating layer solution: weighing 20g of polylactic acid, adding the polylactic acid into an ethyl acetate solution, properly stirring to fully dissolve the polylactic acid, weighing triclosan according to 8% of the mass of the polylactic acid, adding the triclosan into the polylactic acid solution, and uniformly stirring to obtain a coating layer solution;

C. preparing a coating layer: and (3) immersing the pretreated biliary tract stent material into the coating layer solution for 15min, taking out, airing, immersing again, repeating for 5 times, taking out, and drying in vacuum for 60h to obtain the biliary tract stent material containing the coating layer.

Example 3

A. Pretreatment of a base material: cutting the biliary tract stent material into 1 × 1cm, polishing, grinding, removing oil, cleaning and drying for later use, wherein sodium bicarbonate solution with the concentration of 20% is selected for removing oil, deionized water is selected for cleaning and matched with ultrasonic wave for assistance, and drying is carried out under the condition of nitrogen;

B. preparation of coating layer solution: weighing 20g of polylactic acid, adding the polylactic acid into an ethyl acetate solution, properly stirring to fully dissolve the polylactic acid, weighing triclosan according to 12% of the mass of the polylactic acid, adding the triclosan into the polylactic acid solution, and uniformly stirring to obtain a coating layer solution;

C. preparing a coating layer: and (3) immersing the pretreated biliary tract stent material into the coating layer solution for 15min, taking out, airing, immersing again, repeating for 5 times, taking out, and drying in vacuum for 60h to obtain the biliary tract stent material containing the coating layer.

Example 4

A. Pretreatment of a base material: cutting the biliary tract stent material into 1 × 1cm, polishing, grinding, removing oil, cleaning and drying for later use, wherein sodium bicarbonate solution with the concentration of 20% is selected for removing oil, deionized water is selected for cleaning and matched with ultrasonic wave for assistance, and drying is carried out under the condition of nitrogen;

B. preparation of coating layer solution: weighing 20g of polylactic acid, adding the polylactic acid into an ethyl acetate solution, properly stirring to fully dissolve the polylactic acid, weighing triclosan according to 15% of the mass of the polylactic acid, adding the triclosan into the polylactic acid solution, and uniformly stirring to obtain a coating layer solution;

C. preparing a coating layer: and (3) immersing the pretreated biliary tract stent material into the coating layer solution for 15min, taking out, airing, immersing again, repeating for 5 times, taking out, and drying in vacuum for 60h to obtain the biliary tract stent material containing the coating layer.

Example 5

A. Pretreatment of a base material: cutting the biliary tract stent material into 1 × 1cm, polishing, grinding, removing oil, cleaning and drying for later use, wherein sodium bicarbonate solution with the concentration of 20% is selected for removing oil, deionized water is selected for cleaning and matched with ultrasonic wave for assistance, and drying is carried out under the condition of nitrogen;

B. preparation of coating layer solution: weighing 20g of polylactic acid, adding the polylactic acid into an ethyl acetate solution, properly stirring to fully dissolve the polylactic acid, weighing triclosan according to 20% of the mass of the polylactic acid, adding the triclosan into the polylactic acid solution, and uniformly stirring to obtain a coating layer solution;

C. preparing a coating layer: and (3) immersing the pretreated biliary tract stent material into the coating layer solution for 15min, taking out, airing, immersing again, repeating for 5 times, taking out, and drying in vacuum for 60h to obtain the biliary tract stent material containing the coating layer.

Example 6

A. Pretreatment of a base material: cutting the biliary tract stent material into 1 × 1cm, polishing, grinding, removing oil, cleaning and drying for later use, wherein sodium bicarbonate solution with the concentration of 20% is selected for removing oil, deionized water is selected for cleaning and matched with ultrasonic wave for assistance, and drying is carried out under the condition of nitrogen;

B. preparation of coating layer solution: weighing 20g of polylactic acid, adding the polylactic acid into an ethyl acetate solution, properly stirring to fully dissolve the polylactic acid, weighing triclosan according to 30% of the mass of the polylactic acid, adding the triclosan into the polylactic acid solution, and uniformly stirring to obtain a coating layer solution;

C. preparing a coating layer: and (3) immersing the pretreated biliary tract stent material into the coating layer solution for 15min, taking out, airing, immersing again, repeating for 5 times, taking out, and drying in vacuum for 60h to obtain the biliary tract stent material containing the coating layer.

Next, the samples tested in examples 1 to 6 were evaluated for antibacterial properties and biocompatibility.

The test method of the antibacterial performance comprises the following steps: concentration of the selected bacterial liquid is 4X 10⁸The bacterial liquid for test (cfu/ml) of Staphylococcus aureus was added to the surface of the sample in an amount of 0.2ml, and the mixture was treated at 37 ℃ and RH>Culturing for 48h under 90% conditions, then taking out a sample, counting viable bacteria, and obtaining the antibacterial rate through counting. Each sample was run in 5 replicates and a coated biliary stent without triclosan was used as a control. Wherein, the formula for calculating the antibacterial rate is as follows:

R(％)＝(A-B)/A×100

in the formula: r represents the antibacterial rate;

a represents the average number of recovered bacteria in the control group;

b represents the average number of recovered bacteria in the example sample.

In addition, the biocompatibility of the test sample is evaluated through a hemolysis experiment, and the specific method comprises the following steps: the sample is directly contacted with blood, and the amount of hemoglobin released after rupture of erythrocyte membrane is measured to detect the degree of hemolysis in vitro of each sample. The absorption wavelength of hemoglobin is 545nm, and its concentration can be detected by a spectrophotometer. The specific operation steps are as follows:

(1) blood is collected from the heart of a healthy rabbit by 100mL, and 2% potassium oxalate by 5mL is added to prepare fresh anticoagulation blood. And taking 40mL of anticoagulation blood, and adding 50mL of 0.9% sodium chloride injection for dilution.

(2) Taking 3 silicified test tubes, loading a test sample and 10mL of sodium chloride injection into one test tube, taking a blank of one test tube as a negative control group, adding 10mL of sodium chloride normal saline, and taking a blank of the other test tube as a positive control group, and respectively adding 10mL of distilled water.

(3) All the test tubes are kept constant in a water bath at 37 ℃ for 30min, 5mL of anticoagulated rabbit blood is added respectively, and the temperature is kept at 37 ℃ for 60 min.

(4) The supernatant of the test tube was taken and the absorbance was measured at 545 nm. Three replicates of each sample were run and averaged.

The hemolysis rate is calculated as follows:

hemolysis ratio (%) (sample average absorbance-absorbance in negative group)/(absorbance in positive group-absorbance in negative group) × 100

Specifically, the experimental results are shown in table 1.

TABLE 1 antibacterial and hemolytic rates of examples 1-6

Sample numbering	Antibacterial ratio/%)	Percent of hemolysis%
			Example 1	65.7	2.1
Example 2	76.3	3.6
			Example 3	79.6	3.7
Example 4	81.2	4.6
			Example 5	85.4	8.3
Example 6	87.1	11.7

As can be seen from table 1, as the content of triclosan in the coating solution increases, the content of the antibacterial agent in the coating increases, and the antibacterial performance of the biliary stent coating is further improved, however, the antibacterial performance is improved, and the biocompatibility of the coating material is reduced, and when the content of triclosan in the coating solution is 30% of that of polylactic acid, the hemolysis rate is as high as 11.7%, and generally, the hemolysis rate below 5% is considered to be a satisfactory experimental result.

In order to improve the biocompatibility of the biliary stent under the condition of ensuring the antibacterial rate, we further make various attempts, and finally find that the biocompatibility of the biliary stent can be improved by adding the graphene ethanol dispersion liquid into the coating layer solution, and specific experimental results are shown in table 2, wherein the base sample refers to that the graphene ethanol dispersion liquid is added into the coating layer solution on the basis of the corresponding embodiment, and the graphene content refers to the mass ratio of graphene to polylactic acid.

TABLE 2 antibacterial and hemolytic rates after graphene addition

Base sample	Content of graphene/%)	Antibacterial ratio/%)	Percent of hemolysis%
				Example 5	1	85.6	3.3
Example 5	3	85.7	0.9
				Example 5	5	85.9	1.6
Example 5	15	89.2	10.6
				Example 6	1	87.1	4.3
Example 6	3	87.3	1.2
				Example 6	5	87.4	3.7
Example 6	15	90.0	16.7

As can be seen from table 2, after a small amount of the graphene ethanol dispersion is added to the coating layer solution, the hemolysis rate of the coating layer can be greatly reduced, and in consideration of experimental errors, it can be considered that the small amount of graphene has almost no influence on the antibacterial performance of the coating layer. However, the influence of the addition amount of graphene on the performance of the coating shows an irregular trend, and when the addition amount of graphene is up to 15%, the obtained result is that the antibacterial rate is improved, and the biocompatibility is further deteriorated.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.