Ureteral stent with antibacterial coating

Abstract

The utility model relates to ureteral stent technical field, concretely is a kind of ureteral stent with antibacterial coating, including ureteral stent, the ureteral stent one end is connected with distal end curl, the ureteral stent other end is connected with proximal end curl, the ureteral stent, distal end curl and proximal end curl are evenly provided with several side holes on it. The utility model adopts the three-layer functional structure design of bottom layer, middle layer and surface layer, the division of labor of each layer is clear and is realized synergistic effect by chemical bonding, and is not simple single mixed coating, uses the compounding combination of antibacterial peptide and zinc-doped zirconium phosphate silver-loaded nano particles, and zinc doping not only synergistic effect, more key is to play the role of stable and control silver ion release rate, avoids the burst release and too fast depletion of silver, adopts zwitterionic polymer polysulfobetaine pSBMA as outermost layer, constructs the physical barrier of anti-protein, antibacterial, anti-mineral crystal adhesion using its superhydration capacity.

Description

Technical Field

[0001] This utility model relates to the field of ureteral stent technology, specifically to a ureteral stent with an antibacterial coating. Background Technology

[0002] After ureteral stent (double-J stent) implantation, bacteria in the urine adhere to its surface, proliferate, and secrete extracellular matrix, forming a biofilm. Once the biofilm forms, antibiotics have difficulty penetrating it, leading to refractory catheter-related urinary tract infections (CAUTI). Urinary minerals (such as calcium oxalate and magnesium ammonium phosphate) deposit on the biofilm, causing stent scaling, blocking the lumen, and causing discomfort such as pain, hematuria, and urinary frequency. In severe cases, it can lead to kidney failure or even sepsis. Traditional systemic antibiotic treatment has little effect on biofilms and may even exacerbate bacterial resistance.

[0003] Generally, the main shortcomings of existing technologies include limited functionality and inability to comprehensively address problems. For example, silver coatings primarily focus on sterilization, but their ability to combat mineral scaling is weak or nonexistent. Scale buildup can cover the coating, rendering it ineffective, and the scaling itself can cause complications. The release behavior of antibacterial agents is uncontrollable; most coatings release excessively high doses of antibacterial agents in the initial implantation phase, after which the concentration rapidly declines, failing to maintain an effective antibacterial concentration over a period of several months, leaving a long "protective window" with significant safety and drug resistance risks. For instance, antibiotic coatings release sub-therapeutic concentrations of antibiotics locally for extended periods, creating a breeding ground for bacterial resistance and posing a huge potential public health risk. Their effectiveness against biofilms is limited; existing technologies are generally ineffective against established, mature biofilms. For example, antibiotics have difficulty penetrating the biofilm matrix, and silver ions may be captured and inactivated by extracellular polymeric substances (EPS).

[0004] Based on this, the present invention provides a ureteral stent with an antibacterial coating to solve the aforementioned technical problems. Utility Model Content

[0005] The purpose of this invention is to provide a ureteral stent with an antibacterial coating, thereby solving the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: This utility model proposes a ureteral stent with an antibacterial coating, comprising a ureteral stent, one end of which is connected to a distal coil and the other end of which is connected to a proximal coil. The ureteral stent, the distal coil, and the proximal coil are uniformly provided with a plurality of side holes. The outer side of the ureteral stent is coated with a bonding layer, a bactericidal layer, and an anti-adhesion layer in sequence from the inside to the outside.

[0007] Preferably, the bonding layer material is dopamine and its derivatives.

[0008] Preferably, the bactericidal layer material is a pH-sensitive biodegradable polymer.

[0009] Preferably, the anti-adhesion layer is made of a zwitterionic polymer.

[0010] Compared with the prior art, the beneficial effects of this utility model are: This invention employs a three-layer functionalized structure design consisting of a bottom layer, a middle layer, and a top layer. Each layer has a clear function and achieves synergistic effects through chemical bonding, rather than a simple single mixed coating. It uses a combination of antimicrobial peptides and zinc-doped zirconium phosphate-loaded silver nanoparticles. Zinc doping not only enhances the synergistic effect but, more importantly, stabilizes and regulates the release rate of silver ions, preventing sudden release and rapid depletion of silver. A specific pH-sensitive polymer, chitosan, is selected as the middle layer matrix, allowing it to swell and degrade only in acidic urine induced by infection, accelerating the release of antimicrobial agents and enabling intelligent switching from continuous low doses to high doses during infection. Polydopamine is used as the bottom layer to solve the problem of strong adhesion to inert scaffold substrates. A zwitterionic polymer brush is precisely grafted onto the surface layer using surface SI-ATRP technology to form a dense, strong, and uniform anti-adhesion layer. The zwitterionic polymer polysulfobetaine pSBMA is used as the outermost layer, utilizing its super hydration capacity to construct a physical barrier against protein, bacteria, and mineral crystal adhesion. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the antibacterial coated ureteral stent structure of this utility model; Figure 2 This is a schematic diagram of the cross-sectional structure of the ureteral stent with antibacterial coating of this utility model.

[0012] Legend: 1. Ureteral stent; 2. Side hole; 3. Distal curl; 4. Proximal curl; 5. Supporting layer; 6. Sterilizing layer; 7. Anti-adhesion layer. Detailed Implementation

[0013] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0014] Please see Figures 1 to 2This utility model proposes a ureteral stent with an antibacterial coating, including a ureteral stent 1, one end of which is connected to a distal coil 3, and the other end of which is connected to a proximal coil 4. A plurality of side holes 2 are evenly opened on the ureteral stent 1, the distal coil 3 and the proximal coil 4. The outer side of the ureteral stent 1 is coated with a firming layer 5, a bactericidal layer 6 and an anti-adhesion layer 7 from the inside to the outside. It should also be noted that the material of the bonding layer 5 is dopamine and its derivatives. One end of the molecules of this layer is strongly attached to the surface of the substrate, and the other end provides abundant active functional groups, including amino and phenolic hydroxyl groups, which provide covalent grafting sites for the middle layer, greatly enhancing the overall coating's firmness and durability, and solving the problem of poor bonding and easy detachment between the coating and the hydrophobic support substrate. It should also be noted that the bactericidal layer 6 is made of a pH-sensitive biodegradable polymer, specifically chitosan; the antibacterial agent is a composite system of "broad-spectrum antimicrobial peptide (AMP)" and "zinc-doped zirconium phosphate silver-loaded nanoparticles (Ag@ZrP(Zn)NPs)". The composite antibacterial agent is uniformly dispersed in a pH-sensitive polymer matrix. When there is no local infection, the coating slowly releases a low dose of antibacterial agent to maintain basic protection. When bacterial infection causes the microenvironment pH value to drop below 6.0, the polymer matrix swells or breaks down chains, accelerating the release of a high concentration of antibacterial agent, thus achieving "intelligent response" and "on-demand drug delivery". It should also be noted that the anti-adhesion layer 7 is made of zwitterionic polymer, specifically polysulfobetaine (pSBMA). The zwitterionic polymer is firmly grafted onto the surface of the middle layer through surface grafting. The zwitterionic material forms a dense "hydration layer" on the coating surface through strong electrostatic hydration, which can effectively block the approach and adhesion of bacteria, proteins and mineral crystals, reducing the starting point of biofilm and scaling from the source. This layer has a porous structure, allowing antibacterial ions and small molecule peptides to pass through smoothly from the lower layer; In a specific implementation, firstly, the ureteral stent 1 is subjected to plasma cleaning to improve surface activity and cleanliness. The cleaned ureteral stent 1 is then immersed in dopamine-Tris buffer solution (pH=8.5) and subjected to a shaking reaction at room temperature in the dark for 4-12 hours to allow the polydopamine layer to be uniformly deposited on the surface of the ureteral stent 1. After removal, the stent is washed with deionized water. An acetic acid solution of the pH-sensitive polymer chitosan is prepared. Antimicrobial peptides and composite nanoparticles (Ag@ZrP(Zn)NPs) are ultrasonically dispersed in the above solution to form a uniform mixed sol. The stent with the firming layer 5 is immersed in this mixed sol and a uniform film is formed by dip coating. Light crosslinking is performed by genipin crosslinking agent to solidify the structure of the sterilization layer 6. The ureteral stent 1 with the middle layer is immersed in a solution containing zwitterionic monomer SBMA. The surface SI-ATRP reaction is initiated by an initiator to graft a zwitterionic polymer brush structure with controllable thickness, uniformity and firmness onto the surface of the sterilization layer 6. Finally, the coated stent is thoroughly cleaned with ultrapure water to remove unreacted monomers, catalysts and physically adsorbed polymers. The stent is then sterilized by ethylene oxide or low-temperature plasma to obtain the ureteral stent 1 with the firming layer 5, the sterilization layer 6 and the anti-adhesion layer 7.

[0015] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0016] The preferred embodiments of this utility model disclosed above are merely illustrative of the present utility model. These preferred embodiments do not exhaustively describe all details, nor do they limit the utility model to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of this utility model, thereby enabling those skilled in the art to better understand and utilize it. This utility model is limited only by the claims and their full scope and equivalents.

Claims

1. A ureteral stent with an antibacterial coating, comprising a ureteral stent (1), characterized in that, One end of the ureteral stent (1) is connected to a distal coil (3), and the other end of the ureteral stent (1) is connected to a proximal coil (4). Several side holes (2) are evenly provided on the ureteral stent (1), the distal coil (3) and the proximal coil (4). The outer side of the ureteral stent (1) is coated with a firming layer (5), a bactericidal layer (6) and an anti-adhesion layer (7) from the inside to the outside.

2. The ureteral stent with an antibacterial coating according to claim 1, characterized in that, The material of the solid layer (5) is dopamine and its derivatives.

3. A ureteral stent with an antibacterial coating according to claim 2, characterized in that, The bactericidal layer (6) is made of a pH-sensitive biodegradable polymer.

4. A ureteral stent with an antibacterial coating according to claim 3, characterized in that, The anti-adhesion layer (7) is made of zwitterionic polymer.

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