Preparation method of polyvinyl alcohol hydrophilic film on surface of medical catheter
By forming a cross-linked polyvinyl alcohol hydrophilic film on the surface of medical catheters, the balance problem between the hydrophilicity and mechanical properties of the catheter surface is solved, the production cost is reduced, the biocompatibility and safety are improved, and the long-term stable use of the catheter is achieved.
Patent Information
- Application Number
- CN202510846490.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-24
- Publication Date
- 2025-09-26
AI Technical Summary
Existing strategies for hydrophilizing the surfaces of medical catheters have problems such as difficulty in balancing surface hydrophilicity and mechanical properties, biosafety risks induced by chemical modification, and high production costs, leading to coating failure, tissue damage, and infection risks.
A water-insoluble polyvinyl alcohol hydrophilic film is formed on the surface of the medical catheter by inducing molecular cross-linking with an alkaline solution. The polyvinyl alcohol solution is applied by dipping, spraying or brushing, and cross-linked in an alkaline solution to form a cross-linked polyvinyl alcohol hydrophilic film.
It achieves high biocompatibility, low cost, excellent mechanical properties and non-toxicity on the catheter surface, avoids coating damage, reduces friction coefficient and improves hydrophilicity, reduces harmful residues, and improves the service life and safety of the catheter.
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of surface modification of biomedical materials, and specifically relates to a method for constructing a polyvinyl alcohol hydrophilic film on the surface of a medical catheter by inducing molecular cross-linking with an alkaline solution. The method is particularly suitable for lubricating functional treatment of the surface of medical catheters such as interventional catheters and urinary catheters. Background Art
[0002] Surface hydrophilization strategies based on polymer blending, covalent grafting and physical adsorption coatings have been widely used in the field of interventional devices, but their technical limitations have restricted clinical translation effects. The polymer blending method can achieve a modified stability of more than 6 months by compounding hydrophilic polymers (such as PEG, PVP) with matrix materials. However, the blending process causes a significant deterioration in the mechanical properties of the substrate. Covalent grafting technology uses plasma or radiation pretreatment to introduce active sites on the surface of the material, and then grafts zwitterionic polymer brushes. Although this scheme can obtain an interfacial bonding strength of more than 2MPa, high-energy pretreatment will cause damage to the microstructure of the substrate, resulting in a loss of device compliance. Physical adsorption coatings (such as dip coating) are widely used due to their simple process, but their reliance on a binding mechanism of weak intermolecular interactions limits the durability of the coating.
[0003] The existing technology system faces three core contradictions: First, the difficulty of balancing surface hydrophilicity and mechanical properties. For example, while grafting modification improves coating wear resistance, it also reduces catheter bending fatigue life. Second, chemical modification poses biosafety risks. Third, the economic bottlenecks brought about by the complex process chain, and the multi-step processing flow increases production costs, seriously hindering industrialization. The combined effect of these deficiencies means that current hydrophilic devices still face clinical pain points such as coating failure, tissue damage, and infection risks in long-term implant applications. New modification strategies are urgently needed to break through the existing technical framework. Summary of the Invention
[0004] To address the problems with existing solutions for improving the hydrophilicity of medical catheter surfaces, the present invention proposes to improve the hydrophilicity of the medical catheter surface by inducing molecular cross-linking of polyvinyl alcohol (PVA) coated on the surface of the medical catheter using an alkaline solution to form a water-insoluble polyvinyl alcohol hydrophilic film. To achieve the above objectives, the present invention primarily comprises the following aspects:
[0005] A method for preparing a polyvinyl alcohol hydrophilic film on the surface of a medical catheter comprises the following steps:
[0006] (1) Cleaning the medical catheter to be modified and setting it aside;
[0007] (2) Weighing a predetermined mass of polyvinyl alcohol and a corresponding volume of deionized water, and adding the two to a reaction vessel; then placing the reaction vessel in a constant temperature bath, heating it to above 80° C., and mechanically stirring it at a constant speed under constant temperature conditions until the polyvinyl alcohol is completely dissolved, ultimately forming a polyvinyl alcohol aqueous solution with a concentration of 0.5 wt.% to 25 wt.%.
[0008] (3) applying a polyvinyl alcohol solution on the surface of a clean medical catheter by dipping, spraying or brushing, and repeating the operation after drying until a uniform polyvinyl alcohol film is formed; wherein the dipping method is to immerse the medical catheter in the polyvinyl alcohol solution and then take it out and dry it; the spraying method is to use an atomizer to atomize the polyvinyl alcohol solution and then spray it onto the catheter surface and dry it at the same time; the brushing method is to use a brush or a scraper to evenly apply the polyvinyl alcohol solution on the catheter surface and then dry it, and repeat multiple times.
[0009] (4) Weighing a predetermined mass of an alkali source, wherein the alkali source is selected from at least one of sodium tripolyphosphate, lithium hydroxide, calcium hydroxide, sodium hydroxide, or concentrated ammonia water; measuring a corresponding volume of deionized water; adding the alkali source and deionized water into a reaction vessel, and mechanically stirring at a constant speed until completely dissolved, to prepare an alkaline aqueous solution with a concentration of 0.5 mol / L to 10 mol / L.
[0010] (5) The medical catheter coated with polyvinyl alcohol is completely immersed in an alkaline solution for 0.5 to 24 hours, taken out, and then completely immersed in deionized water for 0.5 to 24 hours to form a cross-linked polyvinyl alcohol hydrophilic film on the catheter surface through a cross-linking reaction.
[0011] (6) Immersing the medical catheter with the cross-linked polyvinyl alcohol hydrophilic film in deionized water for multiple soaking and cleaning until the residual alkaline substances and uncross-linked polyvinyl alcohol molecules are completely removed.
[0012] Furthermore, the surface material of the medical catheter is selected from hydrophobic polymer materials such as polyamide (PA), latex (natural rubber), poly(dimethylsiloxane) (PDMS), poly(ethylene) (PE), poly(ethylene terephthalate) (PET), poly(propylene) (PP), poly(styrene) (PS), poly(tetrafluoroethylene) (PTFE), poly(polyurethane) (PU), and polyvinyl chloride (PVC).
[0013] Furthermore, the medical catheter is selected from intravascular angiography catheters, balloon dilatation catheters, central venous catheters, over-the-needle peripheral catheters, micro-floating catheters, arteriovenous pressure measuring catheters, angiography catheters, balloon catheters, PTCA catheters, PTA catheters, microcatheters, thrombolytic catheters, guide catheters, ablation catheters, tracking balloons, hard guidewires, soft-tip guidewires, renal artery guidewires, microguidewires, push guidewires, super-smooth guidewires, arterial sheaths, venous sheaths, micro-puncture sheath filters, spring emboli, embolic microspheres, platinum microemboli, occluders, and urinary catheters.
[0014] Furthermore, the polyvinyl alcohol ([C2H4O] n Polyvinyl alcohol (PVA) is an organic compound. Its degree of polymerization is classified into ultra-high (molecular weight 250,000-300,000), high (molecular weight 170,000-220,000), medium (molecular weight 120,000-150,000), and low (molecular weight 25,000-35,000). The degree of alcoholysis generally ranges from 78%, 88%, and 98%. Partial alcoholysis typically ranges from 87% to 89%, while complete alcoholysis ranges from 98% to 100%. Polyvinyl alcohol grades include, but are not limited to, PVA 1792, PVA 1799, and PVA 224.
[0015] Furthermore, the alkali source is a water-soluble alkaline compound selected from alkali metal hydroxides, alkali metal carbonates, alkali metal phosphates or alkaline earth metal hydroxides. The constant temperature heating device can be a constant temperature water bath, a constant temperature oil bath, a constant temperature sand bath, an oven, etc.;
[0016] Compared with the existing methods for improving the hydrophilicity of medical catheter surfaces, the present invention has the following outstanding advantages:
[0017] First, the modifier selected by the present invention, polyvinyl alcohol, has good biocompatibility, is non-toxic and is the only exogenous organic substance that can be degraded in the body;
[0018] Second, the modifiers, equipment, and devices used in the present invention are common and readily available, which means that the process of the present invention has low cost and versatility.
[0019] Third, the cross-linked polyvinyl alcohol hydrophilic film on the surface of the medical catheter is insoluble in water, and the cross-linked polyvinyl alcohol hydrophilic film has excellent mechanical properties, which can avoid damage and falling off during use.
[0020] Fourthly, the process for improving the hydrophilicity of the surface of a medical catheter proposed by the present invention will not cause damage to the medical catheter or destroy its mechanical properties.
[0021] Fifth, the product obtained by the process for improving the hydrophilicity of the surface of the medical catheter proposed in the present invention does not have the problem of residual toxic organic matter (formaldehyde, glutaraldehyde) and heavy metal ions.
[0022] Specific implementation cases
[0023] The present invention is further described in detail below by way of examples, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.
[0024] Example 1
[0025] Clean the central venous catheter to be modified and set aside. Weigh 40g of polyvinyl alcohol (PVA 224) and 2L of deionized water and add them to a reaction vessel. The reaction vessel is then placed in a thermostatic bath, heated to above 85°C, and mechanically stirred at a constant speed under constant temperature until the polyvinyl alcohol (PVA 224) is completely dissolved, forming a 2 wt.% polyvinyl alcohol aqueous solution. The surface of the central venous catheter is immersed in the polyvinyl alcohol solution and then removed and dried. Repeat this process 30 times.
[0026] Weigh 40g of sodium hydroxide, measure 1L of deionized water and add it to a reaction vessel. Mechanically stir at a constant speed until completely dissolved to prepare an alkaline aqueous solution with a concentration of 1mol / L. A central venous catheter coated with polyvinyl alcohol (PVA 224) is completely immersed in the alkaline solution and soaked for 24 hours, then taken out and completely immersed in deionized water for 10 hours. After cross-linking reaction, a cross-linked polyvinyl alcohol hydrophilic film is formed on the surface of the central venous catheter. The central venous catheter with the cross-linked polyvinyl alcohol hydrophilic film is immersed in deionized water for multiple soaking and cleaning until the residual alkaline substances and uncross-linked polyvinyl alcohol molecules are completely removed. Thus, the polyvinyl alcohol hydrophilic film is modified on the surface of the central venous catheter. The friction coefficient of the unmodified central venous catheter is reduced from 5.59 to 0.66, and the contact angle is reduced from 85° to 30°.
[0027] Example 2
[0028] Clean the PTCA catheter to be modified and set aside. Weigh 10g of polyvinyl alcohol (PVA 1799) and 1L of deionized water and add them to a reaction vessel. The reaction vessel is then placed in a constant-temperature bath, heated to 90°C, and mechanically stirred at a constant speed until the polyvinyl alcohol (PVA 1799) is completely dissolved, ultimately forming a 1wt.% polyvinyl alcohol aqueous solution. Atomize the 1wt.% polyvinyl alcohol (PVA 1799) solution onto the clean PTCA catheter using an atomizer and spray it onto the catheter surface, allowing it to dry.
[0029] Weigh 112g of potassium hydroxide and add 1L of deionized water to a reaction vessel. Mechanically stir at a constant speed until completely dissolved to produce an alkaline aqueous solution with a concentration of 2mol / L. A PTCA catheter coated with polyvinyl alcohol (PVA 1799) was completely immersed in the alkaline solution for 0.5 hours, then removed and completely immersed in deionized water for 1 hour. A cross-linked polyvinyl alcohol hydrophilic film was formed on the catheter surface through a cross-linking reaction. The PTCA catheter coated with the cross-linked polyvinyl alcohol hydrophilic film was immersed in deionized water and rinsed multiple times until the residual alkaline substances and uncross-linked polyvinyl alcohol molecules were completely removed. Thus, the polyvinyl alcohol hydrophilic film was modified on the surface of the PTCA catheter. The friction coefficient of the unmodified PTCA catheter was reduced from 6.5 to 0.77, and the contact angle was reduced from 80° to 29°.
[0030] Example 3
[0031] Clean the catheter to be modified and set aside. Weigh 100g of polyvinyl alcohol (PVA 1788) and 1L of deionized water and add them to a reaction vessel. Then place the reaction vessel in a constant temperature bath, heat it to 95°C, and mechanically stir it at a constant speed under constant temperature conditions until the polyvinyl alcohol is completely dissolved, eventually forming a polyvinyl alcohol (PVA 1788) aqueous solution with a concentration of 10wt.%. Use a brush to evenly apply the 10wt.% polyvinyl alcohol (PVA1788) aqueous solution on the clean catheter surface and then dry it. Repeat 10 times.
[0032] Weigh 115g of lithium hydroxide and 1L of deionized water; add the alkali source and deionized water to a reaction vessel and mechanically stir at a constant speed until completely dissolved to produce an alkaline aqueous solution with a concentration of 5mol / L. A catheter coated with polyvinyl alcohol (PVA 1788) is completely immersed in the alkaline solution for 6 hours, then removed and completely immersed in deionized water for 6 hours to form a cross-linked polyvinyl alcohol hydrophilic film on the catheter surface through a cross-linking reaction. The catheter with the cross-linked polyvinyl alcohol hydrophilic film is immersed in deionized water and rinsed multiple times until the residual alkaline substances and uncross-linked polyvinyl alcohol molecules are completely removed. Thus, the polyvinyl alcohol hydrophilic film is modified on the catheter surface. The friction coefficient of the unmodified catheter is reduced from 5.7 to 0.65, and the contact angle is reduced from 76° to 28°.
Claims
1. A method for preparing a polyvinyl alcohol hydrophilic film on the surface of a medical catheter, comprising two main steps: coating the surface of the medical catheter with polyvinyl alcohol, and cross-linking the polyvinyl alcohol coating with an alkaline solution to form the polyvinyl alcohol hydrophilic film, characterized in that: (1) Polyvinyl alcohol coating on the surface of medical catheters The process of coating the surface of a medical catheter with polyvinyl alcohol comprises two steps in chronological order: preparing a polyvinyl alcohol solution (I) and coating the polyvinyl alcohol solution on the surface of the medical catheter (II).
1. Preparation of polyvinyl alcohol solution Weighing a predetermined mass of polyvinyl alcohol and a corresponding volume of deionized water, and adding the two to a reaction vessel; then placing the reaction vessel in a constant temperature bath, heating it to above 80° C., and mechanically stirring it at a constant speed under constant temperature until the polyvinyl alcohol is completely dissolved, ultimately forming a polyvinyl alcohol aqueous solution with a concentration of 0.5 wt.% to 25 wt.%; II. Evenly coat the polyvinyl alcohol solution on the surface of the medical catheter Applying a polyvinyl alcohol solution to a clean medical catheter surface by dipping, spraying, or brushing, and repeating the process after drying until a uniform polyvinyl alcohol film is formed; wherein the dipping method involves immersing the medical catheter in the polyvinyl alcohol solution and then removing it for drying; the spraying method involves atomizing the polyvinyl alcohol solution with an atomizer and then spraying it onto the catheter surface while drying; and the brushing method involves using a brush or scraper to evenly apply the polyvinyl alcohol solution to the catheter surface and then drying, and repeating the process multiple times. (2) Alkaline solution cross-linked polyvinyl alcohol coating The process of cross-linking the polyvinyl alcohol on the surface of a medical catheter with an alkaline solution includes three steps in chronological order: preparing the alkaline solution (I), cross-linking the polyvinyl alcohol on the surface of the medical catheter with the alkaline solution (II), and cleaning (III). I. Preparation of alkaline solution Weighing a predetermined mass of an alkaline source, the alkaline source being selected from at least one of sodium tripolyphosphate, lithium hydroxide, calcium hydroxide, sodium hydroxide, or concentrated ammonia solution; measuring a corresponding volume of deionized water; adding the alkaline source and deionized water into a reaction vessel, and mechanically stirring at a constant speed until completely dissolved, to prepare an alkaline aqueous solution with a concentration of 0.5 mol / L to 10 mol / L; II. Alkaline solution cross-linking of polyvinyl alcohol on the surface of medical catheters The medical catheter coated with polyvinyl alcohol is completely immersed in an alkaline solution for 0.5 to 24 hours, then taken out and completely immersed in deionized water for 0.5 to 24 hours to form a cross-linked polyvinyl alcohol hydrophilic film on the catheter surface through a cross-linking reaction; III. Cleaning The medical catheter with the cross-linked polyvinyl alcohol hydrophilic film on its surface is immersed in deionized water for multiple immersion cleaning until the residual alkaline substances and uncross-linked polyvinyl alcohol molecules are completely removed.
2. The method for preparing a polyvinyl alcohol hydrophilic film on the surface of a medical catheter according to claim 1, characterized in that: The surface material of the medical catheter is selected from polyamide (PA), latex (natural rubber), poly(dimethylsiloxane) (PDMS), poly(ethylene) (PE), poly(ethylene terephthalate) (PET), poly(propylene) (PP), poly(styrene) (PS), poly(tetrafluoroethylene) (PTFE), poly(polyurethane) (PU), and polyvinyl chloride (PVC).
3. The method for preparing a polyvinyl alcohol hydrophilic film on the surface of a medical catheter according to claim 1, characterized in that: Medical catheters are selected from intravascular angiography catheters, balloon dilatation catheters, central venous catheters, over-the-needle peripheral catheters, micro-floating catheters, arteriovenous pressure measurement catheters, angiography catheters, balloon catheters, PTCA catheters, PTA catheters, microcatheters, thrombolytic catheters, guide catheters, ablation catheters, tracking balloons, hard guidewires, soft-tip guidewires, renal artery guidewires, micro guidewires, push guidewires, super-smooth guidewires, arterial sheaths, venous sheaths, micro-puncture sheath filters, spring emboli, embolic microspheres, platinum microemboli, occluders, and urinary catheters.
4. The method for preparing a polyvinyl alcohol hydrophilic film on the surface of a medical catheter according to claim 1, characterized in that: Polyvinyl alcohol (C2H4O]n) is an organic compound. The degree of polymerization of polyvinyl alcohol is divided into ultra-high degree of polymerization (molecular weight 250,000-300,000), high degree of polymerization (molecular weight 170,000-220,000), medium degree of polymerization (molecular weight 120,000-150,000) and low degree of polymerization (25,000-35,000); the degree of alcoholysis is 78%, 88% and 98%. The degree of alcoholysis of partial alcoholysis is 87%-89%, and the degree of alcoholysis of complete alcoholysis is 98%-100%. Polyvinyl alcohol models include polyvinyl alcohol 17-92, polyvinyl alcohol 17-99 and polyvinyl alcohol 224.
5. The method for preparing a polyvinyl alcohol hydrophilic film on the surface of a medical catheter according to claim 1, characterized in that: The alkali source is a water-soluble alkaline compound selected from alkali metal hydroxides, alkali metal carbonates, alkali metal phosphates or alkaline earth metal hydroxides.