A long-acting antibacterial coating stent and a preparation method and application thereof

Abstract

The application provides a long-acting antibacterial coating stent and a preparation method and application thereof, wherein the long-acting antibacterial coating stent comprises a stent body and a multilayer antibacterial coating, the multilayer antibacterial coating is alternately coated on the surface of the stent, the coating on the inner wall and the outer wall of the stent body comprises three layers of nano silver gel and two layers of polyethylene imine alternately formed, the nano gel coating is formed by mixing the nano silver gel and the polydopamine according to a solution volume ratio of 1:1, and the uniform coating is ensured by using a spin coating method, the stent is suitable for being applied to a ureteral stent, has good bactericidal performance and excellent anti-adhesion capacity, and can reduce urinary tract infections and stent surface crust caused by stent placement and other problems.

Description

Technical Field

[0001] This invention relates to the field of ureteral stent technology, and in particular to a long-lasting antibacterial coated stent, its preparation method, and its application. Background Technology

[0002] Ureteral stents and catheters are essential tools in the diagnosis and treatment of many urinary tract diseases (urinary tract stones, ureteral stricture, urinary tract injury, difficulty urinating, urinary tract surgery, etc.). Through their supporting and dilating effects, they can not only ensure smooth drainage of urine in the upper and lower urinary tracts, but also promote injury healing and stone expulsion.

[0003] As foreign bodies in the urinary tract, urinary stents often cause proteins or bacteria in the urine to adhere to their surface after entering the body. These adherent bacteria then secrete polysaccharide matrix, fibrin, and lipoproteins to form a bacterial biofilm, leading to refractory urinary tract infections. Such stent-related urinary tract infections are usually not suppressable with antibiotics. Furthermore, the presence of the biofilm formed after bacterial adhesion and the unique metabolic microenvironment of the urinary tract can cause calcium or non-calcium crystalline substances in the urine to adhere to and accumulate on the stent surface, resulting in a crust formation. These limitations are more pronounced in patients requiring long-term ureteral stent placement, increasing the treatment cost and discomfort associated with the need for regular stent replacements.

[0004] Antimicrobial coatings aim to use surface modification and coating technologies to apply antimicrobial agents to the surface of materials. Through the release or contact sterilization of antimicrobial substances, they inhibit bacterial adhesion and survival on scaffolds, and resist the formation and adhesion of urinary crystals, thereby inhibiting bacterial biofilm formation and ultimately preventing infection and crusting. This is considered one of the most effective preventative measures. Currently, commonly used antimicrobial coatings employ antimicrobial agents such as antibiotics, antimicrobial peptides, triclosan, and nano-silver complexes. Related research results also show that antimicrobial coatings can reduce the occurrence of infection and surface crusting to a certain extent.

[0005] However, various calcium crystals, proteins, and changes in urine pH in the urinary environment can all affect the stability and function of antibacterial coating materials. For example, when the stent surface is covered by non-bacterial substances, the antibacterial properties of the coating may be rendered ineffective. Similarly, the poor penetration and drug resistance of bacterial biofilms formed on the stent surface are also important reasons why many antibacterial coating solutions have been eliminated. Therefore, how to achieve long-term antibacterial and anti-adhesion effects and maintain stable function in the special microenvironment of the urinary tract has become one of the urgent problems to be solved in the research of novel urinary tract stents. Summary of the Invention

[0006] One advantage of this invention is that it provides a long-lasting antibacterial coated stent, its preparation method, and its application. By using a multi-layer assembly technique, a long-lasting antibacterial coating is applied to the surface of the ureteral stent to obtain a long-lasting antibacterial coated ureteral stent, which can achieve a stable bactericidal effect in the urine environment, thereby inhibiting infection.

[0007] One advantage of this invention is that it provides a long-lasting antibacterial coated stent, its preparation method, and its application. It can achieve long-lasting antibacterial and anti-adhesion properties and function stably in the special microenvironment of the urinary tract. This is of great significance for solving problems such as urinary tract infections and stent surface crusting caused by stent placement in the urology field.

[0008] Another advantage of this invention is that it provides a long-lasting antibacterial coated stent, its preparation method and application. The inner and outer coatings of the ureteral stent are treated separately, and finally, three layers of nanogel and two layers of polyethyleneimine are alternately coated. The multilayer material can effectively ensure the long-lasting antibacterial effect.

[0009] Another advantage of this invention is that it provides a long-lasting antibacterial coating scaffold, its preparation method and application. In the preparation process, a rotation coating method is used, which makes the coating more uniform and stable, and can maintain good bactericidal and long-lasting stable anti-crusting performance.

[0010] Another advantage of the present invention is that it provides a long-lasting antibacterial coating stent, its preparation method and application. The long-lasting antibacterial coating not only has long-lasting antibacterial properties, but also has good cell compatibility, is safe and non-cytotoxic, can reduce tissue inflammation, and is suitable for application in the field of ureteral stents.

[0011] Another advantage of this invention is that it provides a long-lasting antibacterial coated stent, its preparation method and application, which has antibacterial effect against a variety of common bacteria, is degradable, has good biocompatibility, and the ureteral stent coated with the long-lasting antibacterial coating is suitable for use after urinary tract stone surgery, ureteral stricture, and malignant tumors such as cervical cancer.

[0012] According to one aspect of the present invention, a method for preparing a long-lasting antibacterial coated scaffold is provided, comprising the following steps: (S10) Prepare a long-lasting antibacterial coating solution; (S20) Treat the surface of the support material; (S30) Coating the inner wall of the support tube; and (S40) Coating the outer wall of the support tube.

[0013] The step (S10) includes the following steps: (S101) preparation of nanogel; (S102) preparation of nanosilver gel; (S103) preparation of first coating solution; and (S104) preparation of second coating solution.

[0014] In step (S101), the polyepoxide compound and the thiol compound are dissolved in DMF solvent to a total concentration of 5%, wherein the molar ratio of thiol and epoxy functional groups is in the range of 1.2-1:1. Nanogels are prepared by proton transfer polymerization using either 1,8-diazacyclo[5.4.0]undec-7-ene (DBU) or triethylamine as a catalyst. In step (S102), silver nitrate is added to the nanogels, wherein the thiol functional groups... The silver nitrate molar ratio is 1:1-3, and the nano-silver gel is prepared by reduction with sodium borohydride; wherein in step (S103), a 10 mmol / L tris(hydroxymethyl)aminomethane buffer solution is prepared, the pH is adjusted to 8.5 with hydrochloric acid, a 2 mg / mL dopamine solution is prepared with the buffer solution, and then mixed with the 2 mg / mL nano-silver gel prepared in step (S102) so that the volume ratio of dopamine solution to nano-silver gel solution is 1:1, thus obtaining the first coating solution.

[0015] In step (S104), the second coating solution is 3 mg / mL polyethyleneimine.

[0016] In step (S20), the stent material is rinsed three times alternately with deionized water and 95% ethanol under ultrasonic water bath, with each rinsing time being 5-10 minutes, and then dried with nitrogen to complete the surface treatment of the stent material.

[0017] The step (S30) includes the following steps: (S301) applying a first layer of coating to the inner wall of the stent tube; (S302) applying a second layer of coating to the inner wall of the stent tube; and (S303) applying multiple layers of coating to the inner wall of the stent tube.

[0018] In step (S301), the first coating solution prepared in step (S103) is drawn into the tube wall, the two ends of the tube are sealed, and the support tube is rotated at a 45° angle for 24 hours using a 3D rotator. It is then removed, the inner wall of the tube is washed with deionized water, and dried with nitrogen. At this point, a support tube with a single layer of nano-silver gel coated on the inner wall is formed. In step (S302), the second coating solution prepared in step (S104) is drawn into the wall of the support tube coated with nano-silver gel, the two ends of the tube are sealed, and the support tube is... Using a 3D rotator, rotate the tube at a 45° angle for 30 minutes, remove it, clean the inner wall of the tube with deionized water, and dry it with nitrogen. At this point, a support tube with an inner layer of nano-silver gel and an outer layer of polyethyleneimine is formed. In step (S303), steps (S301) and (S302) are repeated alternately, with step (S301) repeated twice and step (S302) repeated once. The final coating consists of three layers of nano-silver gel and two layers of polyethyleneimine, and the inner wall coating of the tube is now complete.

[0019] The step (S40) includes the following steps: (S401) applying a first layer of coating to the outer wall of the stent tube; (S402) applying a second layer of coating to the outer wall of the stent tube; and (S403) applying multiple layers of coating to the outer wall of the stent tube.

[0020] In step (S401), the two ends of the support material with the inner wall coated are sealed and completely immersed in the first coating solution, the amount of the first coating solution added being 1-2 mL / cm². 2 The stent tube is rotated at a 45° angle for 24 hours using a 3D rotator. The stent tube is then removed, its outer wall is cleaned with deionized water, and dried with nitrogen. This forms a stent tube with a single layer of nano-silver gel coated on its outer wall. In step (S402), the stent tube from step (S401) is completely immersed in the second coating solution, with a concentration of 1-2 mL / cm³. 2 The support tube is rotated at a 45° angle for 30 minutes using a 3D rotator. After removal, the outer wall of the tube is cleaned with deionized water and dried with nitrogen. At this point, a support tube with an inner layer of nano-silver gel and an outer layer of polyethyleneimine is formed on the outer wall. In step (S403), steps (S401) and (S402) are repeated alternately, with step (S401) repeated twice and step (S402) repeated once. The final coating consists of three layers of nano-silver gel and two layers of polyethyleneimine, and the outer wall coating of the tube is now complete.

[0021] According to another aspect of the present invention, the present invention also provides a long-lasting antibacterial coated ureteral stent, comprising: One support body; and A multi-layer composite antibacterial coating, comprising an inner coating and an outer coating, is alternately applied to the inner and outer surfaces of the stent body.

[0022] The multilayer antibacterial coating includes a nano-silver gel coating and a polyethyleneimine coating, wherein the nano-gel coating is formed by mixing the nano-silver gel and the polydopamine in a solution volume ratio of 1:1.

[0023] The inner and outer walls of the scaffold body are coated with three layers of nano-silver gel and two layers of polyethyleneimine in alternating layers.

[0024] According to another aspect of the invention, the invention also provides an application of a long-lasting antibacterial coated stent, wherein the long-lasting antibacterial coating is suitable for application to a ureteral stent.

[0025] The long-lasting antibacterial coated stent comprises a stent body and a multilayer antibacterial coating, wherein the coatings on the inner and outer walls of the stent body each comprise a coating formed by alternating layers of nano-silver gel and two layers of polyethyleneimine. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of an existing ureteral stent tube after it has formed a shell.

[0027] Figure 2 This is a schematic diagram of a long-lasting antibacterial coated ureteral stent according to a preferred embodiment of the present invention.

[0028] Figure 3 This is a morphological diagram of a long-lasting antibacterial coating on a polyurethane substrate according to a preferred embodiment of the present invention.

[0029] Figure 4 These are scanning electron microscope images and hydrophilicity / hydrophobicity test images of the surface of the long-lasting antibacterial coating according to the above-described preferred embodiment of the present invention.

[0030] Figure 5 This is a schematic diagram of the release of silver from the long-lasting antibacterial coated ureteral stent sample according to the above-described preferred embodiment of the present invention.

[0031] Figure 6 This is a schematic diagram of the cytotoxic release of the long-lasting antibacterial coated scaffold sample according to the above-described preferred embodiment of the present invention.

[0032] Figure 7 and Figure 8 This is a schematic diagram of the antibacterial test results of the long-lasting antibacterial coated stent sample and the modified ureteral stent according to the above-described preferred embodiment of the present invention.

[0033] Figure 9 This is a schematic diagram of the long-lasting antibacterial performance test of the long-lasting antibacterial coated ureteral stent according to the above-described preferred embodiment of the present invention in a static artificial urine environment.

[0034] Figure 10 This is a schematic diagram illustrating the long-lasting antibacterial performance test of the long-lasting antibacterial coated ureteral stent according to the above-described preferred embodiment of the present invention in a flowing artificial urine environment.

[0035] Figure 11 This is a schematic diagram illustrating the anti-crusting performance test of the long-lasting antibacterial coated ureteral stent according to the above-described preferred embodiment of the present invention in static and flowing artificial bacterial urine environments.

[0036] Figure 12 This is a schematic diagram illustrating the anti-caking performance test of the long-lasting antibacterial coated ureteral stent according to the above-described preferred embodiment of the present invention in different urine environments.

[0037] Figure 13 This is a schematic diagram illustrating the antibacterial and anti-crusting performance test of the long-lasting antibacterial coated ureteral stent according to the above-described preferred embodiment of the present invention in an animal.

[0038] Figure 14 This is a schematic diagram of the surface calcium and magnesium deposition test of the long-acting antibacterial coated ureteral stent according to the above-described preferred embodiment of the present invention in rats.

[0039] Figure 15 This is a schematic diagram of serum liver function indicators in animals after the long-acting antibacterial coated ureteral stent of the above-described preferred embodiment of the present invention has been used in animals.

[0040] Figure 16 This is a schematic diagram of the pathological results of liver and kidney tissues in an animal after the long-acting antibacterial coated ureteral stent of the above-described preferred embodiment of the present invention has been placed in the animal for a predetermined period of time.

[0041] Figure 17 This is a schematic diagram of bladder tissue inflammation assessment in an animal using the long-acting antibacterial coated ureteral stent according to the above-described preferred embodiment of the present invention.

[0042] Figure 18 The results are based on the test results of the long-lasting antibacterial coated ureteral stent according to the above-described preferred embodiment of the present invention. Detailed Implementation

[0043] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0044] Ureteral stents provide support, dilation, and internal drainage for the ureter, primarily used to relieve obstruction or promote ureteral healing. However, in practice, current ureteral stents, as foreign bodies in the urinary tract, often lead to the adhesion of proteins or bacteria from the urine to their surface. These bacteria then secrete polysaccharide matrix, fibrin, and lipoproteins to form a bacterial biofilm, causing intractable urinary tract infections. Such stent-related urinary tract infections are usually not treatable with antibiotics. Furthermore, the presence of the biofilm formed after bacterial adhesion and the unique metabolic microenvironment of the urinary tract causes calcium or non-calcium crystalline substances in the urine to adhere and accumulate on the stent surface, leading to the formation of a crust. Figure 1 As shown. These limitations are more pronounced in patients requiring long-term ureteral stent placement, increasing the treatment cost and discomfort associated with the need for regular stent replacements.

[0045] To address the aforementioned technical problems, this invention provides a long-lasting antibacterial coated stent, its preparation method, and its application. This stent can achieve a stable bactericidal effect in a urinary environment, thereby inhibiting stent-related urinary tract infections and the formation of a crust on the stent surface.

[0046] Reference Appendix Figure 2 As shown, the long-lasting antibacterial coating stent provided by the present invention includes a stent body 10, an inner coating 20, an outer coating 30, and a channel 40, wherein the channel 40 extends through the head end and the tail end of the stent body 10 to form a working channel for drainage.

[0047] The stent body 10 includes an inner wall 11 and an outer wall 12. The inner coating 20 is applied to the outer side of the inner wall 11, and the outer coating 30 is applied to the outer side of the outer wall 12, so that the inner and outer sides of the stent body 10 of the ureteral stent are covered by coatings, so that the ureter has a long-lasting antibacterial effect.

[0048] Both the inner coating 20 and the outer coating 30 are composite antibacterial coatings. Each coating comprises two types: a nano-silver gel coating and a polyethyleneimine coating. The nano-silver gel coating consists of three layers, and the polyethyleneimine coating consists of two layers. These two coatings are alternately applied to the inner wall 11 and the outer wall 12. This multi-layered coating, formed by alternating layers, achieves a good long-lasting antibacterial effect, effectively preventing bacterial growth and crust formation.

[0049] Those skilled in the art will understand that the number of coatings of the inner coating 20 and the outer coating 30 is not limited to the example of this embodiment, and may be other numbers of coatings, such as alternating coatings of nano-silver gel and polyethyleneimine, or mixed coatings of nano-silver gel and polyethyleneimine.

[0050] The method for preparing a long-lasting antibacterial coated stent provided by the present invention is as follows, wherein the method for preparing a long-lasting antibacterial coated ureteral stent includes the following steps: (S10) Prepare a long-lasting antibacterial coating solution; (S20) Treat the surface of the support material; (S30) Coating the inner wall of the support tube; and (S40) Coating the outer wall of the support tube.

[0051] The step (S10) mentioned above includes the following steps: Preparation of (S101) nanogels; (S102) Preparation of nano-silver gel; (S103) Preparation of the first coating solution; and (S104) Preparation of the second coating solution.

[0052] In step (S101), polyepoxides and thiols are used as reactants, and are dissolved in DMF solvent at a molar ratio of thiol to epoxy functional groups ranging from 1.2 to 1:1, to achieve a total concentration of 5%. Nanogels are then prepared by proton transfer polymerization under an alkaline catalyst.

[0053] The polyepoxide compound is an epoxy compound with at least two epoxy groups, and the thiol compound is a thiol compound containing at least two mercapto groups. The base catalyst is one of 1,8-diazacyclo[5.4.0]undec-7-ene (DBU) or triethylamine. The nanogel achieves an average particle size of 50-400 nm in water. Example 1

[0054] The molar ratio of mercapto to epoxy is 1:1, and the catalyst is 1,8-diazacyclic [5.4.0]undec-7-ene (DBU).

[0055] Weigh 0.168 mmol pentaerythritol tetra-3-mercaptopropionate and 0.336 mmol polyethylene glycol diglycidyl ether, with a mercapto to epoxy molar ratio of 1:1. Dissolve them in 5 mL of DMF solvent and stir magnetically for 30 min. Add 5 μL of LBU solution to the reaction solution and stir magnetically for 24 h under a nitrogen atmosphere to obtain the nanogel. Example 2

[0056] The molar ratio of mercapto to epoxy is 1:1, and the catalyst is triethylamine.

[0057] Weigh 0.168 mmol pentaerythritol tetra-3-mercaptopropionate and 0.336 mmol polyethylene glycol diglycidyl ether, with a mercapto to epoxy molar ratio of 1:1. Dissolve them in 5 mL of DMF solvent and stir magnetically for 30 min. Add 140 μL of triethylamine solution to the reaction solution and stir magnetically for 24 h under a nitrogen atmosphere to obtain nanogels.

[0058] In step (S102), silver nitrate is added to the above-mentioned nanogel in a molar ratio of thiol functional groups to silver nitrate of 1:1-3, and the nanogel is prepared by reduction with sodium borohydride. The average particle size of the silver nanoparticles in the prepared nanogel is 5-50 nm. Example 3

[0059] Take 1 mL of the nanogel prepared in either Example 1 or Example 2, and slowly add 9 mL of deionized water dropwise to the reaction solution at a ratio of 1:9 under magnetic stirring, and stir magnetically for 10 min.

[0060] Add 640 μL of 20 mg / mL silver nitrate solution to the reaction solution and stir magnetically for 8-12 h at room temperature in the dark. Then add 180 μL of 40 mg / mL sodium borohydride to the reaction solution and stir magnetically for 4 h. The prepared nano-silver gel solution is then obtained by dialysis purification. Example 4

[0061] Take 1 mL of the nanogel prepared in either Example 1 or Example 2, and slowly add 9 mL of deionized water dropwise to the reaction solution at a ratio of 1:9 under magnetic stirring, and stir magnetically for 10 min.

[0062] Add 200 μL of 20 mg / mL silver nitrate solution to the reaction solution and stir magnetically for 8-12 h at room temperature in the dark. Then add 20 μL of 40 mg / mL sodium borohydride to the reaction solution and stir magnetically for 4 h. The prepared nano-silver gel solution is then obtained by dialysis purification.

[0063] In step (S103), the first coating solution is prepared. Example 5

[0064] Prepare a 10 mmol / L tris(hydroxymethyl)aminomethane buffer solution and adjust the pH to 8.5 with hydrochloric acid. Use this buffer solution to prepare a 2 mg / mL dopamine solution. After dissolving, quickly mix it with a 2 mg / mL nano-silver gel solution. The volume ratio of dopamine solution to nano-silver gel solution is 1:1.

[0065] In step (S104), the second coating solution is prepared.

[0066] Prepare a 3 mg / mL solution of polyethyleneimine.

[0067] In step (S20), the ureteral stent is made of polyurethane (PU), including thermoplastic polyurethane rubber (TPU) tubing.

[0068] The scaffold material was rinsed three times alternately with deionized water and 95% ethanol under ultrasonic water bath, with each rinsing time being 5-10 minutes, and then dried with nitrogen.

[0069] The step (S30) includes the following steps: (S301) First coating on the inner wall of the support tube; (S302) The second coating on the inner wall of the stent tube; and (S303) Multi-layer coating on the inner wall of the stent tube.

[0070] In step (S301), the first coating solution prepared in step (S103) is drawn into the tube wall, and both ends of the tube are sealed. At room temperature, the stent tube is rotated at a 45° angle for 24 hours using a 3D rotator. Then, the stent tube is removed, the inner wall is gently washed with deionized water to remove excess coating solution, and the stent tube is dried with nitrogen. At this point, a stent tube with a single layer of nano-silver gel coated on the inner wall is formed.

[0071] In step (302), the prepared second coating solution from step (S104) is drawn into the wall of the scaffold tube coated with nano-silver gel, and both ends of the tube are sealed. At room temperature, the scaffold tube is rotated at a 45° angle for 30 minutes using a 3D rotator. Then, the scaffold tube is removed, and the inner wall is gently washed with deionized water to remove excess coating solution. It is then dried with nitrogen gas, resulting in a scaffold tube with an inner layer of nano-silver gel and an outer layer of polyethyleneimine coated on the inner wall.

[0072] In step (S303), steps (S301) and (S302) are repeated alternately, with step (S301) repeated twice and step (S302) repeated once. The final coating consists of three layers of nano-silver gel and two layers of polyethyleneimine, thus completing the coating of the inner wall of the tube.

[0073] The step (S40) includes the following steps: (S401) First coating on the outer wall of the support tube; (S402) The second coating on the outer wall of the support tube; and (S403) Multi-layer coating on the outer wall of the support tube.

[0074] In step (S401), the two ends of the coated support material on the inner wall are sealed, and the material is immersed in the prepared first coating solution, with the amount of the first coating solution added being 1-2 mL / cm². 2 The preferred injection rate for the stent tube is 1 mL / cm². 2 The stent tube is completely immersed in the first coating solution. At room temperature, the stent tube is rotated at a 45° angle for 24 hours using a 3D rotator. Then, the stent tube is removed, the outer wall is gently cleaned with deionized water to remove excess coating solution, and the stent tube is dried with nitrogen gas. At this time, a stent tube with a single layer of nano-silver gel coated on the outer wall is formed.

[0075] Sealing both ends helps protect the inner wall of the coated support tube.

[0076] In step (S402), the support tube from step (S401) is immersed in the prepared second coating solution, and the amount of the second coating solution added is 1-2 mL / cm. 2The preferred injection rate for the stent tube is 1 mL / cm². 2 The stent tube is completely immersed in the second coating solution. At room temperature, the stent tube is rotated at a 45° angle for 30 minutes using a 3D rotator. Then, the stent tube is removed, and the outer wall is gently cleaned with deionized water to remove excess coating solution. It is then dried with nitrogen. At this point, a stent tube with an outer wall coated with an inner layer of nano-silver gel and an outer layer of polyethyleneimine is formed.

[0077] In step (S403), steps (S401) and (S402) are repeated alternately, with step (S401) repeated twice and step (S402) repeated once. The final coating consists of three layers of nano-silver gel and two layers of polyethyleneimine, thus completing the coating on the outer wall of the tube.

[0078] The biological tests for the ureteral stent prepared above are as follows: Test 1: Morphology test of long-lasting antibacterial coating on substrate The morphology of the long-lasting antibacterial coating on the polyurethane substrate in this invention is as follows: Figure 3 As shown (sPTE) Ag Single-layer nano-silver gel coating; mPTE Ag The multilayer nano-silver gel coating of the present invention, wherein... Figure 3 Image A shows the morphology of different coating methods on the surface of the polyurethane board; Figure 3 Image B shows the morphology of the coating of the present invention on the surface of a polyurethane pipe. It can be seen that the spin coating method used in the present invention produces a more uniform coating.

[0079] Test 2: Electron microscopy scanning and surface hydrophilicity / hydrophobicity test of long-lasting antibacterial coating surface The scanning electron microscope image of the long-lasting antibacterial coating surface in this invention is shown below. Figure 4 As shown in A, Figure 4 A is a single-layer nanogel (sPTE) Ag ) and the multilayer nanosilver gel (mPTE) of the present invention Ag Electron microscopy image of the coating on a polyurethane surface. The thickness of the multilayer nano-silver gel coating of the present invention is approximately between 342-359 nm.

[0080] Surface hydrophilicity / hydrophobicity test results are as follows Figure 4 As shown in Figure B, the surface of the long-lasting antibacterial coating of the present invention was tested, and the results showed that its surface has stronger hydrophilicity, with a water contact angle between 28-35°.

[0081] Test 3: Silver Release Test in Figure 5 A represents the silver content at each sampling point. Figure 5 B in the figure represents the cumulative release curve of silver.

[0082] ordinary single-layer nano silver coating (sPTE) Ag Polyurethane board and the multilayer long-lasting antibacterial coating (mPTE) prepared by the present invention Ag Polyurethane plates were cut into 50*10mm pieces and immersed in 6mL of pH=7.4 PBS buffer. The Ag levels under physiological conditions were investigated using an inductively coupled plasma atomic absorption spectrometer. + Release behavior was studied, and the cumulative release of nanosilver over 60 days was calculated. The results are as follows: Figure 5 As shown in the figure, compared with ordinary single-layer nano-silver coating (sPTE) Ag Compared with polyurethane boards, the silver release of the long-lasting antibacterial coating scaffold sample of the present invention is significantly increased, and the modified long-lasting antibacterial coating scaffold provided by the present invention exhibits good cell compatibility.

[0083] Test 4: Cytotoxicity Test (1) Seed the cultured 3T3 cells at a density of 1×10⁴ cells / well into 96-well plates, add 100 μL of DMEM complete medium to each well, and incubate overnight in a cell culture incubator; (2) Remove the old medium, place the substrate (6 mm in diameter) into the well plate, add 100 μL of DMEM basal medium, and incubate for 24 h; (3) Remove the old medium and substrate, wash twice with PBS, add 100 μL of DMEM basal medium containing 10% CCK-8, and continue incubation for 1 h. Measure the optical density at 450 nm in each well using a microplate reader. Set up 6 replicates for each sample. Cell viability is as follows: Figure 6 As shown: The results indicate that the coating was co-cultured with the cells ( Figure 6 (A) The coated scaffold samples showed good cell compatibility in PBS solutions released at 24 and 48 hours.

[0084] Figure 6 The cytotoxicity test was performed, where A represents the cell survival rate after co-culturing the scaffold-coated sample with cells for 24 h, and B represents the cell survival rate after co-culturing the scaffold-coated sample with cells for 24 h and 48 h after release in PBS.

[0085] Test 5: In vitro antibacterial performance test (1) Cut the substrate into small round pieces with a diameter of 6 mm, sterilize with ultraviolet light for 15-30 min, place the substrate in a 96-well plate, and add 10 -5(1) Bacterial suspension with a concentration of CFU / mL; (2) Substrate without antimicrobial nanogel coating was inoculated as a control group; well plate inoculated with bacterial solution without any substrate sample was used as a positive control, and well plate without any bacteria and substrate sample was used as a negative control; (3) All samples and controls were incubated at 37℃ for 24h; (4) 100μL of the solution in the above 96-well plate was evenly spread on an agar plate and incubated for 24h. The colonies were counted. Each group of experiments contained 3 parallel samples. The antibacterial rate of each group of samples was calculated according to the following formula:

[0086] In the antibacterial test, two incubation methods were used: the shaking method and the static method. In the shaking method, the antibacterial test solution was incubated in a shaker at 37°C (120 rpm) for 24 hours. In the static method, the antibacterial test solution was incubated in a hydroponic incubator at 37°C for 24 hours. Ordinary ureteral stents (before modification) and the long-lasting antibacterial coated stent of this invention (after modification) were used as controls. The results are shown in the appendix. Figure 7 As shown in the figure, the long-lasting antibacterial coating support of this invention has an antibacterial effect on bacterial solutions in both static and dynamic states.

[0087] Antibacterial performance was tested in an artificial urine environment. The bacteria were co-incubated with common Gram-negative bacteria of the urinary tract and methicillin-resistant Staphylococcus aureus for 24 hours. Results are shown in the appendix. Figure 8 As shown in Table 1, from the appendix Figure 8 As can be seen from Table 1, the long-lasting antibacterial coating stent prepared by the present invention has antibacterial effects against several common bacteria such as Escherichia coli, Staphylococcus aureus, Proteus mirabilis, and Enterococcus faecalis in a urine environment.

[0088] Table 1. Antibacterial test results of long-lasting antibacterial coated ureteral stents E. coli 99.9% Staphylococcus aureus 99.9% Proteus mirabilis 99.9% Enterococcus faecalis 99.9% Test 6: Long-lasting antibacterial performance in urine environment The prepared samples, including single-layer samples and uncoated polyurethane ureteral stent samples, were cut into 6*6 mm sizes. Artificial urine was prepared (calcium chloride 0.49 g / L, magnesium chloride hexahydrate 0.65 g / L, sodium chloride 4.6 g / L, disodium sulfate 2.3 g / L, trisodium citrate dihydrate 0.65 g / L, disodium oxalate 0.02 g / L, potassium dihydrogen phosphate 2.8 g / L, potassium chloride 1.6 g / L, ammonium chloride 1.0 g / L, urea 25 g / L, gelatin 5.0 g / L). The samples were immersed in the bacterial solution and incubated for 30 days. Bacteria were added at different time points for plating. Figure 9 As shown, the coated polyurethane material of the present invention exhibits superior antibacterial properties over time in environments with four types of bacteria and mixed bacteria compared to single-layer materials.

[0089] Figure 9Long-lasting antibacterial test in a static artificial urine environment: A: Escherichia coli, B: Staphylococcus aureus, C: Enterococcus faecalis, D: Proteus mirabilis, E: a mixture of four bacteria. The coating prepared according to this invention was applied to the inner wall of a silicone tube, and its long-lasting antibacterial properties were tested in an artificial urine circulation environment simulating urine flow (flow rate 1 mL / min, 37°C). Figure 10 As shown, in the context of flowing urine infected with Escherichia coli and Proteus mirabilis, it exhibits a longer-lasting bactericidal effect compared to monolayers.

[0090] Test 7: Anti-crust test The coating prepared according to this invention was applied to a polyurethane plate, cut into 10*3mm pieces, and immersed in 10mL of artificial urine containing Proteus mirabilis for 24 hours. The pH of the urine was measured at different time points. After 24 hours, the sample was removed and scanned under an electron microscope. The results are as follows: Figure 11 As shown in Figure A, the coating prepared by this invention can kill bacteria more quickly, thereby inhibiting the increase in pH caused by urease produced by bacteria, and ultimately inhibiting the formation of magnesium ammonium phosphate precipitate, keeping the urine clear, and its surface has almost no crystal deposits. After 30 days of testing in a flowing urine environment under the same conditions, the results are as follows... Figure 11 As shown in Figure B, it can maintain good bactericidal and anti-crusting properties.

[0091] Figure 11 A: Anti-crust performance test under static artificial bacterial urine conditions; B: Long-term anti-crust performance test under flowing artificial bacterial urine conditions.

[0092] In addition, the long-term anti-crusting performance of the long-lasting antibacterial coating stent of this invention was tested under different artificial urine environments, and compared with ordinary ureteral stents as a reference. The comparative test results in normal artificial urine, hypercalciuria, and hyperoxaluria are shown in the appendix. Figure 12 As shown in the figure, the long-lasting antibacterial coating stent of this invention exhibits highly efficient anti-crusting properties in various urine environments.

[0093] Test 8: Antibacterial and Anti-crusting Test in Animals The prepared sample and uncoated polyurethane material were cut into 4*2mm pieces. 6-8 week old SD rats were selected. The rats were fasted for 12 hours prior to surgery and anesthetized via intraperitoneal injection. After anesthesia, the rats were weighed, fixed, and disinfected. A midline incision was made in the abdomen to locate and expose the bladder. Urine was aspirated with a syringe and flushed with physiological saline. A 5mm incision was made at the top of the bladder, the stent sample was inserted, and the bladder, subcutaneous muscle tissue, and outer skin were sutured layer by layer. Rats were sacrificed on days 15 and 30 post-implantation, the stent was removed, and its surface morphology was tested using SEM. The test results are as follows: Figure 13 and Figure 14 As shown in the results, compared with the control group (uncoated polyurethane material, i.e., PU before modification), the long-lasting antibacterial composite coating of the present invention also exhibits good antibacterial and long-lasting stable anti-crusting effects in the urine environment of animals.

[0094] Figure 13 : Surface electron microscopy and urine smear results after implantation in animals; Figure 14 The amount of calcium and magnesium deposited on the surface of the material 15 and 30 days after implantation in animals.

[0095] Test 9: Animal Safety Test Thirty days after implantation in the rat bladder, the silver content in both blood and urine was below the detection line, as shown in Table 2 and Appendix. Figure 15 The animal's liver and kidney function indicators were all within the normal range, and the liver and kidney pathological tissue results after 30 days were as follows: Figure 16 As shown, no obvious abnormalities were observed in the liver and kidney tissues, indicating that the coating of the present invention has good safety and biocompatibility. (See attached reference.) Figure 17 As shown, the long-lasting antibacterial coated scaffold (i.e., modified PU) provided by the present invention causes less inflammation in the surrounding tissue.

[0096] Figure 15 Serum liver and kidney function indicators in animals 15 and 30 days after implantation were measured. Figure 16 The images show the pathological results of liver and kidney tissues in animals 30 days after implantation. A: Liver, B: Kidney.

[0097] Table 2. Silver content tests in urine and blood of animals 15 and 30 days after implantation. Table 2. Silver content tests in urine and blood of animals 15 and 30 days after implantation.

[0098] " / " indicates that the sample does not contain silver, and "-" indicates that the silver content is below the detection limit, <10 ppb / mL.

[0099] The test results above show that the long-lasting antibacterial coated stent prepared by the above method has multiple alternating layers forming a composite coating with uniform surface coating. In biological testing, the long-lasting antibacterial coated stent provided by this invention is non-cytotoxic, has good biocompatibility, and possesses antibacterial and anti-crusting properties, making it suitable for clinical application as a ureteral stent.

[0100] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the present invention. The objectives of the present invention have been fully and effectively achieved. The functions and structural principles of the present invention have been demonstrated and explained in the embodiments, and any variations or modifications may be made to the implementation of the present invention without departing from the stated principles.

Claims

1. A method for preparing a long-lasting antibacterial coated ureteral stent, characterized in that, Includes the following steps: (S10) Prepare a long-lasting antibacterial coating solution, including preparing a nano-silver gel, mixing the nano-silver gel solution with a polydopamine solution to form a first coating solution, and preparing a polyethyleneimine solution as a second coating solution. The step (S10) includes the following steps: (S101) Preparation of nanogel: dissolving a polyepoxide compound and a thiol compound in DMF solvent, using one of 1,8-diazacyclo[5.4.0]undec-7-ene or triethylamine as a catalyst, and preparing nanogel by proton transfer polymerization; (S102) Preparation of nanosilver gel: adding silver nitrate to the nanogel, and reducing it with sodium borohydride to prepare nanosilver gel; (S103) Preparation of the first coating solution: mixing a dopamine solution and the nanosilver gel solution in a volume ratio of 1:1 to obtain the first coating solution; In step (S101), the total concentration of the polyepoxide compound and the thiol compound is 5%, wherein the molar ratio of thiol functional groups to epoxy functional groups is in the range of 1.2-1:

1. In step (S102), the molar ratio of thiol functional groups to silver nitrate is 1:1-3. In step (S103), a 10 mmol / L tris(hydroxymethyl)aminomethane buffer solution is prepared, and the pH is adjusted to 8.5 with hydrochloric acid. A 2 mg / mL dopamine solution is prepared with this buffer solution, and then mixed with the 2 mg / mL nano-silver gel prepared in step (S102) to obtain the first coating solution. (S20) Treat the surface of the ureteral stent material; (S30) Coating the inner wall of the ureteral stent: First, a first coating solution is applied to the inner wall of the ureteral stent to form a first layer of nano-silver gel coating; then, a second coating solution is applied to the inner wall of the ureter to form a second layer of polyethyleneimine coating; the above steps are repeated alternately to ultimately form multiple alternating layers of nano-silver gel coating and polyethyleneimine coating on the inner wall of the ureteral stent; and (S40) Coating the outer wall of the ureteral stent: First, seal both ends of the ureteral stent after the inner wall coating is completed. Then, apply the first coating solution to the outer wall of the ureteral stent to form the first layer of nano-silver gel coating on the outer wall. Next, apply the second coating solution to the outer wall of the ureteral stent to form the second layer of polyethyleneimine coating on the outer wall. Repeat the above steps alternately to finally form multiple layers of alternating nano-silver gel coating and polyethyleneimine coating on the outer wall of the ureteral stent.

2. The method for preparing the long-acting antibacterial coated ureteral stent according to claim 1 further includes a step (S104) of preparing a second coating solution, wherein the second coating solution is a 3 mg / mL polyethyleneimine solution.

3. The method for preparing a long-lasting antibacterial coated ureteral stent according to claim 1 or 2, wherein in step (S20), the stent material is rinsed three times alternately with deionized water and 95% ethanol under ultrasonic water bath, with each rinsing time being 5-10 minutes, and then dried with nitrogen to complete the surface treatment of the stent material.

4. The method for preparing the long-lasting antibacterial coated ureteral stent according to claim 3, wherein step (S30) includes the following steps: (S301) First coating of the inner wall of the ureteral stent: The prepared first coating solution is drawn into the tube wall, both ends of the tube are sealed, and the stent is rotated at a 45° angle for 24 hours using a 3D rotator. The stent is then removed, the inner wall is washed with deionized water, and dried with nitrogen. At this point, a ureteral stent with a single layer of nano-silver gel coated on the inner wall is formed. (S302) Second coating of the inner wall of the ureteral stent: The prepared second coating solution is drawn into the tube wall of the ureteral stent coated with nano-silver gel, both ends of the tube are sealed, and the ureteral stent is rotated using a 3D rotator. The instrument is rotated at a 45° angle for 30 minutes, then removed and the inner wall of the tube is cleaned with deionized water and dried with nitrogen. At this time, a ureteral stent with an inner layer of nano-silver gel and an outer layer of polyethyleneimine is formed on the inner wall. (S303) The multi-layer coating of the inner wall of the ureteral stent is repeated alternately with the steps (S301) and (S302), wherein step (S301) is repeated twice and step (S302) is repeated once, and finally a tube inner wall coating composed of three layers of nano-silver gel and two layers of polyethyleneimine is formed.

5. The method for preparing the long-lasting antibacterial coated ureteral stent according to claim 4, wherein step (S40) includes the following steps: (S401) The first coating layer is applied to the outer wall of the ureteral stent. The stent material with the inner wall coated is sealed at both ends and immersed in the first coating solution, the amount of which is 1-2 mL / cm. 2 Ureteral stent: The ureteral stent is rotated at a 45° angle for 24 hours using a 3D rotator. The ureteral stent is then removed, its outer wall is cleaned with deionized water, and dried with nitrogen. At this point, a ureteral stent with a single layer of nano-silver gel coated on its outer wall is formed. (S402) Second coating of the outer wall of the ureteral stent: The ureteral stent from step (S401) is immersed in a second coating solution, the amount of which is 1-2 mL / cm². 2 The ureteral stent is rotated at a 45° angle for 30 minutes using a 3D rotator. After removal, the outer wall of the stent is cleaned with deionized water and dried with nitrogen. At this point, a ureteral stent with an inner layer of nano-silver gel and an outer layer of polyethyleneimine is formed on the outer wall. (S403) Multi-layer coating of the outer wall of the ureteral stent is carried out alternately. Steps (S401) and (S402) are repeated alternately, with step (S401) repeated twice and step (S402) repeated once, finally forming a tube outer wall coating composed of three layers of nano-silver gel and two layers of polyethyleneimine.

6. A long-lasting antibacterial coated ureteral stent prepared by the preparation method according to any one of claims 1 to 5, characterized in that, include: One ureteral stent body; and A multi-layer composite antibacterial coating, comprising an inner coating and an outer coating, which are alternately applied to the inner and outer surfaces of the scaffold body, wherein both the inner coating and the outer coating comprise coatings formed by alternating layers of nano-silver gel and multiple layers of polyethyleneimine.

7. The long-lasting antibacterial coated ureteral stent according to claim 6, wherein each of the composite antibacterial coatings comprises a nano-silver gel coating and a polyethyleneimine coating, wherein the nano-gel coating is formed by mixing the nano-silver gel and the polydopamine at a solution volume ratio of 1:1, wherein the concentration of the polyethyleneimine solution is 3 mg / mL.

8. The long-lasting antibacterial coated ureteral stent according to claim 6, wherein both the inner coating and the outer coating comprise a coating formed by alternating layers of three layers of nano-silver gel and two layers of polyethyleneimine.

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