Method for surface modification of a biomaterial with an ultrathin hydrophilic lubricating coating and applications thereof

Abstract

This invention relates to a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating and its application. The method comprises: mixing plasma-treated biomaterials with a precursor solution and performing an in-situ polymerization reaction to obtain biomaterials with an ultrathin hydrophilic lubricating coating; the precursor solution includes dopamine or its salt, zwitterionic monomers, and Tris buffer. The ultrathin hydrophilic lubricating coating prepared by the method of this invention can reduce the friction coefficient of biomaterial surfaces and has strong hydrophilic lubrication properties; it can form ultrathin hydrophilic lubricating coatings on the surfaces of different biomaterials, is suitable for surface modification of most biomaterials, has a simple and easy process, good hydrophilic lubrication properties, and can effectively improve the surface lubrication performance of biomedical materials.

Description

Technical Field

[0001] This invention belongs to the field of biomaterial surface modification technology, specifically relating to a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating and its application. Background Technology

[0002] Because the materials used in interventional medical devices lack lubrication, the friction between them and human tissues is significant during their movement within the body, which can increase patient discomfort during the detection and treatment of diseases. For example, the high friction during the movement of a capsule endoscope in the gastrointestinal tract can damage human tissues and organs. Furthermore, the significant friction can affect the movement of the capsule endoscope, impacting examination results.

[0003] Currently, friction can be reduced by lubricating the surface of medical devices. Methods for hydrophilic modification of polymer materials to enhance lubrication include surface coating, high-energy radiation, plasma modification, surface oxidation, and grafting modification. However, these common methods have drawbacks such as complex operation processes, specialized equipment, high energy consumption, and specific requirements for the substrate material. Therefore, a simpler, more convenient, non-toxic, harmless, and biocompatible lubricating coating preparation method is needed. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating and its application. The ultrathin hydrophilic lubricating coating prepared by the method of this invention can reduce the friction coefficient of the surface of biomaterials and has strong hydrophilic lubricating properties.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for modifying the surface of a biomaterial with an ultrathin hydrophilic lubricating coating, the method comprising: mixing plasma-treated biomaterial with a precursor solution and performing an in-situ polymerization reaction to obtain a biomaterial with an ultrathin hydrophilic lubricating coating; wherein the precursor solution comprises dopamine or its salt, zwitterionic monomers and Tris buffer.

[0007] Dopamine is a catecholamine neurotransmitter found in the central nervous system and a major component of mussel adhesive proteins. It can spontaneously polymerize in a weakly alkaline environment and spontaneously deposit on the surface of biomaterials, exhibiting excellent adhesion properties. Polydopamine (PDA) has a large number of hydrophilic hydroxyl and amino groups on its surface, which can significantly improve the wettability of material surfaces and can serve as adhesive sites, assisting covalently or non-covalently bonded target polymers in forming co-deposited coatings.

[0008] In this invention, dopamine monomers undergo oxidative polymerization in a weakly alkaline environment, forming a polydopamine linking layer on the surface of biomaterials. Simultaneously, the polydopamine acts as a polymerization initiator, generating numerous free radicals to initiate the polymerization of zwitterionic monomers. The wet adhesion effect of polydopamine allows the lubricating zwitterionic polymer to adhere well to the biomaterial surface, forming a stable hydrophilic lubricating coating. Plasma treatment increases the hydroxyl and carboxyl groups on the biomaterial surface, enhancing its chemical activity and surface energy, which facilitates the bonding between the biomaterial and the lubricating coating. The ultrathin hydrophilic lubricating coating prepared by the method of this invention can reduce the coefficient of friction on the biomaterial surface and exhibits strong hydrophilic lubricating properties.

[0009] Preferably, the atmosphere for plasma treatment is oxygen; the power of plasma treatment is 100-400W, for example, 100W, 120W, 150W, 180W, 200W, 220W, 250W, 280W, 300W, 320W, 350W, 380W, 400W, etc.; the plasma treatment time is 15-60min, for example, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min, 60min, etc.

[0010] Other specific point values ​​within the range of the above values ​​can be selected, and will not be elaborated on here.

[0011] The power and time of plasma treatment determine the kinetic energy of the incident ions and the number of free radicals formed on the material surface. In this invention, the plasma treatment is set with specific power and time, resulting in an ultrathin hydrophilic lubricating coating with a lower coefficient of friction and stronger hydrophilic lubrication performance.

[0012] Preferably, the concentration of dopamine or its salt in the precursor solution is 1-5 mg / mL, for example, it can be 1 mg / mL, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL, 3 mg / mL, 3.5 mg / mL, 4 mg / mL, 4.5 mg / mL, 5 mg / mL, etc.

[0013] Other specific point values ​​within the range of the above values ​​can be selected, and will not be elaborated on here.

[0014] The oxidative polymerization of dopamine monomers further initiates the polymerization reaction of zwitterionic monomers. The concentration of dopamine monomers affects the generation of free radicals, which in turn affects the degree of polymerization of zwitterionic monomers. In this invention, a specific concentration range of dopamine monomers is set, resulting in an ultrathin hydrophilic lubricating coating with a lower coefficient of friction and stronger hydrophilic lubrication properties.

[0015] Preferably, the mass ratio of the dopamine or its salt to the zwitterionic monomer is 1:(10-25), for example, it can be 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, 1:21, 1:22, 1:23, 1:24, 1:25, etc.

[0016] Other specific point values ​​within the range of the above values ​​can be selected, and will not be elaborated on here.

[0017] The content of zwitterionic monomers is crucial to the formation of hydrophilic lubricating coatings. However, more zwitterionic monomers are not necessarily better; rather, as the content increases, the hydrophilic lubricating properties of the coating initially increase and then decrease. In this invention, the content of zwitterionic monomers is set within a specific range, resulting in an ultrathin hydrophilic lubricating coating with a lower coefficient of friction and stronger hydrophilic lubricating properties.

[0018] Preferably, the zwitterionic monomer comprises any one or a combination of at least two of sulfobetaine methacrylate, 2-methacryloyloxyethyl phosphocholine, or carboxybetaine methacrylate.

[0019] Preferably, the zwitterionic monomer comprises a combination of sulfobetaine methacrylate and 2-methacryloyloxyethyl phosphoric acid choline, sulfobetaine methacrylate and carboxybetaine methacrylate, or 2-methacryloyloxyethyl phosphoric acid choline and carboxybetaine methacrylate.

[0020] In this invention, the two zwitterionic monomers have a synergistic effect, and compared with a single zwitterionic monomer, the resulting ultrathin hydrophilic lubricating coating has a lower coefficient of friction and stronger hydrophilic lubrication performance.

[0021] Preferably, the mass ratio of sulfobetaine methacrylate to 2-methacryloyloxyethyl phosphoric acid choline, sulfobetaine methacrylate to carboxybetaine methacrylate, or 2-methacryloyloxyethyl phosphoric acid choline to carboxybetaine methacrylate is independently (5-15):(5-15).

[0022] The specific point values ​​in the first (5-15) can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, etc.; the specific point values ​​in the second (5-15) can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, etc.

[0023] Other specific point values ​​within the range of the above values ​​can be selected, and will not be elaborated on here.

[0024] In this invention, zwitterionic monomers exhibit superior synergistic effects within a specific mass ratio range.

[0025] Preferably, the concentration of the Tris buffer is 8-12 mM, for example, it can be 8 mM, 8.5 mM, 9 mM, 9.5 mM, 10 mM, 10.5 mM, 11 mM, 11.5 mM, 12 mM, etc.; the pH of the Tris buffer is 8-9, for example, it can be 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9, etc.

[0026] Other specific point values ​​within the range of the above values ​​can be selected, and will not be elaborated on here.

[0027] Preferably, the biomaterial includes any one of polycarbonate, polypropylene, polytetrafluoroethylene, polyvinylidene chloride, silicone rubber, polydimethylsiloxane, polyurethane, polyethylene, polyethylene terephthalate, polylactic acid, or polycaprolactone.

[0028] The method of this invention can form an ultrathin hydrophilic lubricating coating on the surface of different biomaterials, and is applicable to the surface modification of most biomaterials. The process is simple and easy to implement, with good hydrophilic lubricity, and can effectively improve the surface lubrication performance of biomedical materials.

[0029] Preferably, the in-situ polymerization reaction time is 8-24 hours, for example, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, etc.; the in-situ polymerization reaction temperature is 20-30°C, for example, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, etc.

[0030] Other specific point values ​​within the range of the above values ​​can be selected, and will not be elaborated on here.

[0031] Preferably, the in-situ polymerization reaction further includes washing and drying steps.

[0032] Preferably, the solvent used for washing includes ethanol and / or deionized water.

[0033] Preferably, the drying method includes baking or drying with nitrogen gas.

[0034] In a second aspect, the present invention provides the application of the method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating as described in the first aspect in the preparation of medical devices.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The ultrathin hydrophilic lubricating coating prepared by the method of this invention can reduce the friction coefficient of the biomaterial surface and has strong hydrophilic lubricating properties. Specifically, dopamine monomers undergo oxidative polymerization in a weakly alkaline environment, forming a polydopamine linking layer on the biomaterial surface. Simultaneously, it acts as a polymerization initiator, generating a large number of free radicals to initiate the polymerization of zwitterionic monomers. The wet adhesion effect of polydopamine allows the zwitterionic polymer with lubricating properties to adhere well to the biomaterial surface, forming a stable hydrophilic lubricating coating. Plasma treatment can increase the hydroxyl and carboxyl groups on the biomaterial surface, enhancing the chemical activity and surface energy of the biomaterial surface, which is beneficial for the bonding between the biomaterial and the lubricating coating.

[0037] (2) The method of the present invention can form an ultra-thin hydrophilic lubricating coating on the surface of different biomaterials, and is applicable to the surface modification of most biomaterials; the process is simple and easy to implement, and has good hydrophilic lubricity, which can effectively improve the surface lubrication performance of biomedical materials. Attached Figure Description

[0038] Figure 1 Image of the polycarbonate substrate with surface-modified ultrathin hydrophilic lubricating coating (PDA-PSBMA) in Example 1;

[0039] Figure 2 X-ray photoelectron spectroscopy (XPS) spectrum of the ultrathin hydrophilic lubricating coating (PDA-PSBMA) modified on the surface of the polycarbonate substrate in Example 1;

[0040] Figure 3 This is a scanning electron microscope image of the ultrathin hydrophilic lubricating coating (PDA-PSBMA) modified on the surface of the polycarbonate substrate in Example 1.

[0041] Figure 4 This is a scanning electron microscope image of the polydopamine coating (PDA) modified on the surface of the polycarbonate substrate in Comparative Example 2. Detailed Implementation

[0042] To further illustrate the technical means and effects of the present invention, the following describes the technical solution of the present invention in conjunction with preferred embodiments of the present invention. However, the present invention is not limited to the scope of the embodiments.

[0043] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0044] Example 1

[0045] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating, the specific steps of which are as follows:

[0046] (1) The polycarbonate substrate was subjected to plasma treatment at 300W power for 30 minutes in an oxygen atmosphere;

[0047] (2) Preparation of precursor solution: 40 mg dopamine hydrochloride and 600 mg sulfobetaine methacrylate (SBMA) were dissolved in 20 mL Tris buffer solution (10 mM, pH = 8.5);

[0048] (3) The plasma-treated polycarbonate substrate was mixed with the precursor solution for 16 hours to carry out an in-situ polymerization reaction. After the polycarbonate substrate was removed, it was rinsed with deionized water and dried with nitrogen to obtain an ultrathin hydrophilic lubricating coating (PDA-PSBMA) modified on the surface of the polycarbonate substrate. The product appearance is as follows. Figure 1 As shown.

[0049] Example 2

[0050] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating, the specific steps of which are as follows:

[0051] (1) The polypropylene substrate was subjected to plasma treatment at 400W power for 15 minutes in an oxygen atmosphere;

[0052] (2) Preparation of precursor solution: 100 mg dopamine hydrochloride and 2500 mg 2-methacryloyloxyethyl phosphocholine (MPC) were dissolved in 20 mL Tris buffer solution (8 mM, pH=8);

[0053] (3) The plasma-treated polypropylene substrate was mixed with the precursor solution for 8 hours and an in-situ polymerization reaction was carried out. After the polypropylene substrate was taken out, it was rinsed with deionized water and dried with nitrogen to obtain an ultra-thin hydrophilic lubricating coating (PDA-PMPC) modified on the surface of the polypropylene substrate.

[0054] Example 3

[0055] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating, the specific steps of which are as follows:

[0056] (1) The polytetrafluoroethylene material was treated with plasma at 100W power for 60 minutes in an oxygen atmosphere;

[0057] (2) Preparation of precursor solution: 20 mg dopamine hydrochloride and 200 mg carboxybetaine methacrylate (CBMA) were dissolved in 20 mL Tris buffer solution (12 mM, pH=9);

[0058] (3) The plasma-treated polytetrafluoroethylene material was mixed with the precursor solution for 24 hours to carry out in-situ polymerization. After the polytetrafluoroethylene material was taken out, it was rinsed with deionized water and dried with nitrogen to obtain an ultra-thin hydrophilic lubricating coating (PDA-PCBMA) modified on the surface of the polytetrafluoroethylene material.

[0059] Example 4

[0060] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating. The only difference between this method and Example 1 is that "sulfobetaine methacrylate (SBMA)" is replaced with an equal amount of "2-methacryloyloxyethyl phosphocholine (MPC)", while all other raw materials and steps remain unchanged.

[0061] Example 5

[0062] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating. The only difference between this method and Example 1 is that "sulfobetaine methacrylate (SBMA)" is replaced with an equal amount of "carboxybetaine methacrylate (CBMA)," while all other raw materials and steps remain unchanged.

[0063] Example 6

[0064] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating. The only difference between this method and Example 1 is that "600 mg sulfobetaine methacrylate (SBMA)" is replaced with "300 mg sulfobetaine methacrylate (SBMA) and 300 mg 2-methacryloyloxyethyl phosphocholine (MPC)". All other raw materials and steps remain unchanged.

[0065] Example 7

[0066] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating. The only difference between this method and Example 1 is that "600 mg sulfobetaine methacrylate (SBMA)" is replaced with "150 mg sulfobetaine methacrylate (SBMA) and 450 mg carboxybetaine methacrylate (CBMA)", while all other raw materials and steps remain unchanged.

[0067] Example 8

[0068] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating. The only difference between this method and Example 1 is that "600 mg sulfobetaine methacrylate (SBMA)" is replaced with "450 mg 2-methacryloyloxyethyl phosphocholine (MPC) and 150 mg carboxybetaine methacrylate (CBMA)". All other raw materials and steps remain unchanged.

[0069] Example 9

[0070] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating. The only difference between this method and Example 1 is that "600 mg sulfobetaine methacrylate (SBMA)" is replaced with "60 mg sulfobetaine methacrylate (SBMA) and 540 mg 2-methacryloyloxyethyl phosphocholine (MPC)". All other raw materials and steps remain unchanged.

[0071] Example 10

[0072] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating. The only difference between this method and Example 1 is that "600mg sulfobetaine methacrylate (SBMA)" is replaced with "200mg sulfobetaine methacrylate (SBMA)," while all other raw materials and steps remain unchanged.

[0073] Example 11

[0074] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating. The only difference between this method and Example 1 is that "600mg sulfobetaine methacrylate (SBMA)" is replaced with "1200mg sulfobetaine methacrylate (SBMA)," while all other raw materials and steps remain unchanged.

[0075] Example 12

[0076] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating. The only difference between this embodiment and Example 1 is that "40 mg dopamine hydrochloride and 600 mg sulfobetaine methacrylate (SBMA)" are replaced with "10 mg dopamine hydrochloride and 150 mg sulfobetaine methacrylate (SBMA)", while all other raw materials and steps remain unchanged.

[0077] Example 13

[0078] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating. The only difference between this embodiment and Example 1 is that "40 mg dopamine hydrochloride and 600 mg sulfobetaine methacrylate (SBMA)" are replaced with "120 mg dopamine hydrochloride and 1800 mg sulfobetaine methacrylate (SBMA)", while all other raw materials and steps remain unchanged.

[0079] Example 14

[0080] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating. The only difference between this embodiment and Embodiment 1 is that "treatment with 300W plasma for 30 minutes" is replaced with "treatment with 80W plasma for 90 minutes". All other raw materials and steps remain unchanged.

[0081] Example 15

[0082] This embodiment provides a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating. The only difference between this embodiment and Embodiment 1 is that "treatment with 300W plasma for 30 minutes" is replaced with "treatment with 450W plasma for 12 minutes". All other raw materials and steps remain unchanged.

[0083] Comparative Example 1

[0084] This comparative example provides a method for modifying the surface of a biomaterial with an ultrathin hydrophilic lubricating coating. The only difference between this method and Example 1 is that the polycarbonate substrate in step (1) is not subjected to plasma treatment, while the other raw materials and steps remain unchanged.

[0085] Comparative Example 2

[0086] This comparative example provides a method for modifying the surface of a biomaterial with a polydopamine coating. The only difference between this method and Example 1 is that sulfobetaine methacrylate (SBMA) is not added in step (2), while other raw materials and steps remain unchanged, thus obtaining a polydopamine coating (PDA) modified on the surface of a polycarbonate substrate.

[0087] Test Example 1

[0088] (1) X-ray photoelectron spectroscopy (XPS) characterization: XPS analysis was performed on the ultrathin hydrophilic lubricating coating modified on the polycarbonate substrate surface of Example 1. The test results are as follows: Figure 2 As shown, a distinct S2p peak appeared at 166.3 eV, indicating a high S content in the coating, which means that the PDA-PSBMA coating was successfully modified on the surface of the polycarbonate substrate.

[0089] (2) Scanning Electron Microscopy (SEM) Analysis: The ultrathin hydrophilic lubricating coating modified on the polycarbonate substrate surface of Example 1 and the polydopamine coating modified on the polycarbonate substrate surface of Comparative Example 2 were analyzed using a JSM-IT800 scanning electron microscope. The test results are as follows: Figure 3 and Figure 4 As shown, PDA-PSBMA or PDA aggregates are distributed on the surface of the polycarbonate substrate.

[0090] Test Example 2

[0091] (1) Test samples: Coatings for surface modification of biomaterials in Examples 1-15 and Comparative Examples 1-2;

[0092] (2) Coating thickness test: The coating thickness of the sample was measured using a spectroscopic ellipsometry and an atomic force microscope;

[0093] (3) Wetting performance test: The static water contact angle of the sample coating was measured using a DSA-100 contact angle meter;

[0094] (4) Lubrication performance test: In order to simulate the rigid-soft contact interface, a polydimethylsiloxane (PDMS) hemisphere was used instead of a rigid slider to reduce the contact pressure; the CSM friction tester was used to test the sample coating, with a test amplitude of 5 mm and a 1 Hz reciprocating cycle to test the friction coefficient of the sample coating.

[0095] (5) The test results are shown in Table 1:

[0096] Table 1

[0097] sample Coating thickness (nm) Water contact angle (°) coefficient of friction Example 1 32 20 0.013 Example 2 28 23 0.028 Example 3 27 24 0.035 Example 4 30 21 0.014 Example 5 29 22 0.014 Example 6 41 11 0.004 Example 7 38 13 0.005 Example 8 37 13 0.005 Example 9 35 18 0.009 Example 10 23 34 0.068 Example 11 24 30 0.059 Example 12 19 39 0.072 Example 13 22 31 0.063 Example 14 25 30 0.051 Example 15 23 33 0.065 Comparative Example 1 20 42 0.093 Comparative Example 2 15 93 0.11

[0098] Examples 1-5 show that the ultrathin hydrophilic lubricating coating prepared by the method of the present invention can reduce the friction coefficient of the surface of biomaterials and has strong hydrophilic lubricating properties. Examples 6-8 show that there is a synergistic effect between zwitterionic monomers. Example 9 shows that the mass ratio between zwitterionic monomers is crucial to the hydrophilic lubricating properties of the coating. Examples 10-11, 12-13, and 14-15 show that the content of zwitterionic monomers, the concentration of dopamine monomers, and the power and time of plasma treatment also affect the hydrophilic lubricating properties of the coating.

[0099] The applicant declares that this invention illustrates a method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product of this invention, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

[0100] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0101] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A method for modifying the surface of a biomaterial with an ultrathin hydrophilic lubricating coating, characterized in that, The method for modifying the surface of the biomaterial with an ultrathin hydrophilic lubricating coating includes: mixing plasma-treated biomaterial with a precursor solution and performing an in-situ polymerization reaction to obtain a biomaterial with an ultrathin hydrophilic lubricating coating modified on the surface; the precursor solution is dopamine or its salt, zwitterionic monomer and Tris buffer solution; The plasma treatment atmosphere is oxygen, the plasma treatment power is 100-400 W, and the time is 15-60 min; The zwitterionic monomer is a combination of sulfobetaine methacrylate and 2-methacryloyloxyethyl phosphoric acid choline, sulfobetaine methacrylate and carboxybetaine methacrylate, or 2-methacryloyloxyethyl phosphoric acid choline and carboxybetaine methacrylate. The mass ratio of sulfobetaine methacrylate to 2-methacryloyloxyethyl phosphoric acid choline, sulfobetaine methacrylate to carboxybetaine methacrylate, or 2-methacryloyloxyethyl phosphoric acid choline to carboxybetaine methacrylate is independently (5-15):(5-15). The mass ratio of the dopamine or its salt to the zwitterionic monomer is 1:(10-25); The concentration of dopamine or its salt in the precursor solution is 1-5 mg / mL.

2. The method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating according to claim 1, characterized in that, The concentration of the Tris buffer is 8-12 mM, and the pH of the Tris buffer is 8-9.

3. The method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating according to claim 1, characterized in that, The biomaterials include any one of polycarbonate, polypropylene, polytetrafluoroethylene, polyvinylidene chloride, silicone rubber, polydimethylsiloxane, polyurethane, polyethylene, polyethylene terephthalate, polylactic acid, or polycaprolactone.

4. The method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating according to claim 1, characterized in that, The in-situ polymerization reaction takes 8-24 hours and is carried out at a temperature of 20-30°C.

5. The method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating according to claim 1, characterized in that, The in-situ polymerization reaction also includes washing and drying steps.

6. The method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating according to claim 5, characterized in that, The solvent used for washing includes ethanol and / or deionized water.

7. The method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating according to claim 5, characterized in that, The drying methods include baking or drying with nitrogen gas.

8. The application of the method for modifying the surface of biomaterials with an ultrathin hydrophilic lubricating coating according to any one of claims 1-7 in the preparation of medical devices.

Images