Anti-fog coating for medical endoscope lens and preparation method thereof

Abstract

The present invention relates to the field of anti-fog coatings, specifically an anti-fog coating for medical endoscope lenses and a preparation method thereof. The method comprises the following steps: dissolving hydroxyethyl methacrylate and phosphotungstic acid in a mixed solution of water and an organic solvent, adding an initiator, stirring, and polymerizing to obtain a polymer solution; dissolving a hydrophilic zwitterion, hydroxyethyl methacrylate, and magnesium chloride in water, adding an initiator and a cross-linking agent, and stirring to obtain a monomer solution; and mixing the polymer solution with the monomer solution, stirring, spin-coating, and drying the mixture onto a glass slide to obtain the anti-fog coating. Compared with existing technologies, the present invention has advantages such as a low refractive index, high transparency, and resistance to shedding.

Description

Technical Field

[0001] The present invention relates to the field of anti-fog coatings, and in particular to an anti-fog coating for a medical endoscope lens and a preparation method thereof. Background Art

[0002] Endoscopes, such as laparoscopes, arthroscopy, and gastroenteroscopes, are among the most important diagnostic and therapeutic instruments in modern medicine and are widely used in clinical settings. Endoscopes allow direct observation of the morphology of diseased areas or the tissue structure of internal organs, facilitating subsequent diagnosis and treatment. Endoscopes can alleviate patient suffering and improve diagnostic accuracy, leading to their widespread adoption in numerous medical settings. Minimally invasive surgical procedures, in particular, rely heavily on endoscopes.

[0003] As my country's medical technology continues to improve, medical endoscopy technology is becoming increasingly advanced. Minimally invasive surgical procedures are now widely practiced clinically in my country. These procedures primarily rely on an endoscopic system for observation and manipulation, which primarily includes the endoscope system, image display system, lighting system, and flushing and cleaning system. The most critical component of the endoscope system is the camera lens. However, when the endoscopic camera used in current minimally invasive surgery is inserted into the patient's body, temporary fluctuations in temperature and humidity can cause condensation on its surface, affecting the clarity of the surgical field on the display. Therefore, the anti-fog effect of the endoscopic camera is crucial to the success of the surgery, making anti-fog treatment of the endoscopic camera crucial. Traditional methods to address lens fogging include the introduction of a flushing system for cleaning or preheating the lens. However, these methods are time-consuming, lack stability, and do not fundamentally address the problem of endoscope fogging during surgery.

[0004] Hydrophobic or hydrophilic coatings can prevent fog formation due to their water-repellent properties or water absorption and diffusion mechanisms. Hydrophilic coatings, in particular, can adsorb surface water molecules, forming a continuous hydration layer on the substrate surface, reducing light scattering caused by droplets and enhancing light transmittance, thereby exhibiting effective anti-fog properties. Hydrophilic coatings have been proven to be one of the most effective anti-fog methods. However, the hygroscopic expansion of hydrophilic coatings and their weak adhesion to the surface often lead to interfacial damage, wrinkling, and cracking of the coating. The uneven coating surface exacerbates light refraction and scattering, resulting in reduced substrate transparency. Therefore, durable hydrophilic coatings with strong interfacial adhesion have attracted extensive research. Currently, the common method for preparing hydrophilic surfaces is to use polymers rich in hydrophilic functional groups such as hydroxyl (OH), amines (NH2), and carboxyl / ester (COOH / COOR). Synthetic hydrophilic polymers are popular for preparing anti-fog surfaces because they are low-cost, tunable, and have strong interactions with water. However, these methods do not improve the adhesion between the coating and the substrate surface. After absorbing water and swelling, the adhesion is low and it is easy to fall off, which limits its application in medical devices. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide an anti-fog coating for medical endoscope lenses with high adhesion, anti-fog properties and certain antibacterial properties and a preparation method thereof.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A method for preparing an anti-fog coating comprises the following steps:

[0008] Dissolving hydroxyethyl methacrylate (HEMA) and phosphotungstic acid (PTA) in a mixed solution of water and an organic solvent, adding an initiator, stirring, and polymerizing to obtain a polymer solution;

[0009] Dissolving a hydrophilic zwitterion, hydroxyethyl methacrylate, and magnesium chloride in water, adding a crosslinking agent and an initiator, and stirring to obtain a monomer solution;

[0010] The polymer solution and the monomer solution are mixed, stirred, and spin-coated on a glass slide, and then dried to obtain the anti-fog coating.

[0011] Furthermore, the mass ratio of hydroxyethyl methacrylate to phosphotungstic acid is (8-12):(10-14), preferably 10:12.

[0012] Furthermore, the hydrophilic zwitterion is 2-methacryloyloxyethyl phosphorylcholine (MPC).

[0013] Furthermore, the mass ratio of the 2-methacryloyloxyethyl phosphorylcholine to magnesium chloride (MgCl2) is (1-2):0.1.

[0014] Furthermore, the mass ratio of the polymer solution to the monomer solution is 1-3:1, preferably 2:1.

[0015] Furthermore, when the hydrophilic zwitterion, hydroxyethyl methacrylate and magnesium chloride are dissolved in water, hydroxyethyl methacrylate is added to increase the viscosity of the solution, thereby ensuring the hydrophilicity of the material and increasing the crosslinking density, forming an entangled structure and inhibiting swelling. The mass ratio of the hydroxyethyl methacrylate to the hydrophilic zwitterion is (1-2):(0.05-0.1).

[0016] Furthermore, the initiator includes one of benzoyl peroxide, lauroyl peroxide or azobisisobutyronitrile (AIBN).

[0017] Furthermore, the cross-linking agent is N,N'-methylenebisacrylamide.

[0018] Furthermore, the mass ratio of the crosslinking agent to the initiator is (1-1.1):1.

[0019] Furthermore, when preparing the anti-fog coating, the drying temperature is 60-80° C., preferably 70° C., and the drying time is 12-36 hours, preferably 24 hours.

[0020] An anti-fog coating prepared by the method is used for anti-fog modification of medical endoscope lenses.

[0021] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0022] (1) The coating prepared by the present invention has a small refractive index and high transparency, and does not affect the normal use of the endoscope lens: since the molecules on the surface of the hydrophilic coating have a strong affinity with water molecules, water droplets can spread on the coating surface to form a water film, reducing the scattering of light, and establishing a barrier between the coating and the dirt surface, thereby playing an anti-fog and anti-fouling role, which can effectively solve the problem that the medical endoscope lens is prone to fogging and swelling after entering the human body, thereby affecting the observation effect.

[0023] (2) The adhesive layer of the coating of the present invention adopts phosphotungstic acid, and the introduction of its supramolecular effect greatly improves the adhesion of the coating, which can adhere stably for a long time and is not easy to fall off. In addition, the preparation method of the coating of the present invention is simple and easy to mass produce and promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the infrared spectrum characterization diagram of the adhesive layer polymer solution in Example 1;

[0025] Figure 2 This is the infrared spectrum characterization diagram of the anti-fog coating polymer solution in Example 1;

[0026] Figure 3 This is an anti-fog effect diagram of the broken piece in Example 4 and the glass slide without anti-fog coating. DETAILED DESCRIPTION

[0027] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] The following examples are implemented based on the above technical solutions of the present invention, and provide detailed implementation methods and specific operating processes, but the protection scope of the present invention is not limited to the following examples.

[0029] The following are more detailed implementation cases, which further illustrate the technical solutions of the present invention and the technical effects that can be obtained.

[0030] In the following examples, unless otherwise specified, raw materials, reagents or processing techniques are all conventional commercially available products or conventional processing techniques in the art.

[0031] Example 1

[0032] This embodiment provides a method for preparing an anti-fog coating, and the steps are as follows:

[0033] Preparation of adhesive layer: 8g HEMA and 9.6g PTA were dissolved in a mixed solvent of 41.2g water and 41.2g ethylene glycol, and after mixing, 1g initiator: AIBN was added and stirred at room temperature to form a precursor solution. Free radical polymerization was carried out at 70°C under nitrogen atmosphere for 2h to form a polymer solution. The polymer solution was characterized by infrared spectroscopy, as shown in FIG. Figure 1 As shown, 1710cm -1 The red shift of the C=O peak at φ represents the hydrogen bonding interaction between the polymerized hydroxyethyl methacrylate and phosphotungstic acid, indicating that the adhesive layer was successfully prepared.

[0034] Prepare the hydrophilic layer: Dissolve 1g MPC, 0.1g MgCl2, and 0.05g HEMA in 9g water, mix well, then add 0.01g AIBN and 0.01g cross-linker (N,N'-methylenebisacrylamide), and stir well at room temperature to form a monomer solution.

[0035] Preparation of anti-fog coating:

[0036] 3 g of polymer solution was mixed with 1 g of monomer solution, mechanically stirred for 30 min, and then spin-coated on a glass slide (75 mm long, 25 mm wide, and 1 mm thick). The mixture was placed in an oven for drying at 70 ° C for 24 h. Polymerization occurred during the drying process, and the polymer was characterized by infrared spectroscopy. Figure 2 As shown, 1700cm -1 The C=C peak of the zwitterionic MPC disappears, indicating that MPC polymerizes into PMPC and cross-links with HEMA, indicating that the anti-fog coating is successfully prepared. After drying, the anti-fog coating is finally formed on the surface of the glass slide.

[0037] Example 2

[0038] This embodiment provides a method for preparing an anti-fog coating, and the steps are as follows:

[0039] Preparation of the adhesive layer: 10 g HEMA and 12 g PTA were dissolved in a mixed solvent of 39 g water and 39 g ethylene glycol. After mixing, 1 g initiator (AIBN) was added and stirred at room temperature to form a precursor solution. Free radical polymerization was carried out at 70°C under a nitrogen atmosphere for 2 h to form a polymer solution.

[0040] Prepare the hydrophilic layer: Dissolve 1.2g MPC, 0.1g MgCl2, and 0.06g HEMA in 8.8g water, mix well, then add 0.01g AIBN and 0.01g cross-linker (N,N'-methylenebisacrylamide), stir well at room temperature to form a monomer solution;

[0041] Preparation of anti-fog coating:

[0042] 2 g of polymer solution was mixed with 1 g of monomer solution, mechanically stirred for 30 minutes, and then spin-coated on a glass slide (75 mm long, 25 mm wide, and 1 mm thick). The mixture was placed in an oven for drying at 70°C for 24 hours. A polymerization reaction occurred during the drying process, and the anti-fog coating was finally formed on the surface of the glass slide after drying.

[0043] Example 3

[0044] This embodiment provides a method for preparing an anti-fog coating, and the steps are as follows:

[0045] Preparation of the adhesive layer: 12 g HEMA and 15.6 g PTA were dissolved in a mixed solvent of 36.2 g water and 36.2 g ethylene glycol. After mixing, 1 g initiator (AIBN) was added and stirred at room temperature to form a precursor solution. Free radical polymerization was carried out at 70°C under a nitrogen atmosphere for 2 h to form a polymer solution.

[0046] Prepare the hydrophilic layer: Dissolve 1.5g MPC, 0.1g MgCl2, and 0.075g HEMA in 8.5g water, mix well, then add 0.01g AIBN and 0.01g cross-linker (N,N'-methylenebisacrylamide), and stir well at room temperature to form a monomer solution.

[0047] Preparation of anti-fog coating:

[0048] 1 g of polymer solution was mixed with 1 g of monomer solution, mechanically stirred for 30 minutes, and then spin-coated on a glass slide (75 mm long, 25 mm wide, and 1 mm thick). The mixture was placed in an oven for drying at 70°C for 24 hours. A polymerization reaction occurred during the drying process, and the anti-fog coating was finally formed on the surface of the glass slide after drying.

[0049] Example 4

[0050] This embodiment provides a method for preparing an anti-fog coating, and the steps are as follows:

[0051] Preparation of the adhesive layer: 14 g HEMA and 18.2 g PTA were dissolved in a mixed solvent of 33.9 g water and 33.9 g ethylene glycol. After mixing, 1 g initiator (AIBN) was added and stirred at room temperature to form a precursor solution. Free radical polymerization was carried out at 70°C under a nitrogen atmosphere for 2 h to form a polymer solution.

[0052] Prepare the hydrophilic layer: dissolve 2g MPC, 0.1g MgCl2 and 0.1g HEMA in 8g water, mix well, add 0.01g AIBN and 0.01g cross-linker (N,N'-methylenebisacrylamide), stir well at room temperature to form a monomer solution;

[0053] Preparation of anti-fog coating:

[0054] 1 g of polymer solution was mixed with 1 g of monomer solution, mechanically stirred for 30 minutes, and then spin-coated on a glass slide (75 mm long, 25 mm wide, and 1 mm thick). The mixture was placed in an oven for drying at 70°C for 24 hours. A polymerization reaction occurred during the drying process, and the anti-fog coating was finally formed on the surface of the glass slide after drying.

[0055] Detection experiment:

[0056] 1. The anti-fog time of a glass slide coated with an anti-fog coating prepared in Example 4, a glass slide coated only with an adhesive layer (the preparation method is the same as that of the preparation method of the anti-fog coating in Example 4, except that the monomer solution is not added, and the relative amounts of the other components and the process conditions are the same as those in Example 4), a glass slide coated only with a hydrophilic layer (the preparation method is the same as that of the preparation method of the anti-fog coating in Example 4, except that the polymer solution is not added, and the relative amounts of the other components and the process conditions are the same as those in Example 4), an untreated glass slide, and a glass slide coated with a commercially available anti-fog spray (Rainys glasses anti-fog spray) (comparative example) under 80°C hot steam was tested. The coating dimensions were all: 75 mm long, 25 mm wide, and 1 mm thick. The specific results are shown in the following table:

[0057] Table 1: Anti-fog time of glass slides coated with different coatings

[0058] Group Anti-fog time Untreated slides 0min Glass slides coated with adhesive layer only 10min Glass slides coated with a hydrophilic layer only 15min comparison group 20min Example 4 30min

[0059] 2. Perform tensile test:

[0060] In Example 4 above, 1 g of the polymer solution and 1 g of the monomer solution were mixed and mechanically stirred for 30 minutes. Then, 0.2 g was spin-coated on a glass slide (75 mm long, 25 mm wide, and 1 mm thick). The overlap area between the two glass slides, which was also the coating area, was 25×10 mm. The mixture was then placed in an oven for drying at 70° C. for 24 hours. A polymerization reaction occurred during the drying process, and the anti-fog coating was finally formed on the surface of the glass slide after drying.

[0061] 0.2 g of the polymer solution in Example 4 was mechanically stirred for 30 minutes and spin-coated on a glass slide (75 mm long, 25 mm wide, and 1 mm thick). The overlap area between the two glass slides, which was also the coating area, was 25 × 10 mm. The solution was then placed in an oven for drying at 70°C for 24 hours. A polymerization reaction occurred during the drying process, and the adhesive layer was finally formed on the surface of the glass slide after drying.

[0062] 0.2 g of a commercially available anti-fog spray (Rainys Anti-fog Spray for Glasses) was spin-coated on a glass slide (75 mm long, 25 mm wide, and 1 mm thick). The overlap area between the two glass slides, which was also the coating area, was 25 × 10 mm. The slide was then placed in an oven for drying at 70°C for 24 hours. A polymerization reaction occurred during the drying process, and the control group was finally formed on the surface of the glass slide after drying.

[0063] A tensile test was conducted (reference standard: ASTM F2255-05). The test results are shown in the following table:

[0064] Table 2: Adhesion strength of glass slides coated with different coatings

[0065] Group Adhesive strength (dry) Adhesion strength (wet) comparison group 0.8MPa 0.5MPa Adhesion Group 1.5MPa 1.3MPa Example 4 1.5MPa 1.1MPa

[0066] From the results of test experiments 1 and 2, it can be seen that after the anti-fog coating is sprayed on the surface of a transparent material, it can effectively prevent water vapor from condensing into small water droplets on its surface, thereby achieving an anti-fogging effect, and has high bonding strength and is not easy to fall off.

[0067] 3. Biocompatibility evaluation:

[0068] The biocompatibility of this coating was evaluated according to the extract test in GB / T 16886. The specific steps are as follows:

[0069] (1) Extraction

[0070] The cover glass (20×20 mm) containing the coating prepared in Example 1-4 was sterilized by radiation and then extracted with 10% fetal bovine serum DMEM culture medium at 37° C. for 24 hours to obtain an extract.

[0071] (2) Cell culture

[0072] L929 cells in the exponential growth phase were digested with trypsin, and 100 μL of cells with a concentration of 1×10 5 The cell suspension of 100 cells / mL was inoculated into a 96-well plate, with 6 parallel wells for each of the blank group (cultured in normal medium) and the experimental sample group, and cultured in a 37° C., 5% CO 2 incubator for 24 h.

[0073] After 24 h, the culture medium of the experimental group was replaced with an equal volume of the extract, and the culture medium of the control group was replaced normally and cultured for another 24 h.

[0074] (3) Detection

[0075] After culturing for 24 h, 10 μL of CCK-8 (Bebo Biotech) was added to each well, and the absorbance was measured at a wavelength of 450 nm using a microplate reader after incubation for 4 h.

[0076] The relative cell proliferation rate of the experimental group was calculated with the absorbance of the control group as 100%.

[0077] Relative cell proliferation rate = As / Ac×100%

[0078] As: absorbance of experimental wells (containing cells, culture medium, CCK-8 solution and coating extracts);

[0079] Ac: absorbance of control well (containing cells, culture medium, and CCK-8 solution);

[0080] The biological properties of the antifogging agents prepared in Examples 1-4 were judged by combining the relative cell proliferation grading table. The relative proliferation (calculated based on the cell concentration on the 7th day) was graded 0 or 1 and was considered qualified.

[0081] Table 3: Cell relative proliferation grading table:

[0082]

[0083]

[0084] The experimental results are shown in the following table:

[0085] Table 4: Results of relative cell proliferation grading in Examples 1-4

[0086] Group Cell proliferation grading Example 1 1 Example 2 1 Example 3 1 Example 4 1

[0087] 4. Light transmittance test: The light transmittance of the coating was characterized by a UV-visible spectrophotometer. Specifically, the anti-fog coating prepared in Examples 1-4 was evenly coated on a glass slide (75×25 mm) and dried in a 25°C environment for 24 hours. The light transmittance in the wavelength range of 400-900 nm was collected using a UV-visible spectrophotometer under dry conditions. The glass slide coated with the anti-fog coating was then immersed in deionized water for 24 hours, and the light transmittance in the wavelength range of 400-900 nm was collected again using a UV-visible spectrophotometer for comparison. An average transmittance of more than 85% was considered transparent. The test results are as follows:

[0088] Table 5: Light transmittance test results of Examples 1-4

[0089] Group Light transmittance under dry conditions Light transmittance under wet conditions Example 1 93％ 90％ Example 2 91％ 88％ Example 3 92％ 91％ Example 4 90％ 86％

[0090] The results show that the anti-fog coating maintains good light transmittance under both dry and wet conditions, both above 85%, meeting the usage standards.

[0091] At the same time, combined Figure 3 Compared with the glass slide without anti-fog coating, the glass slide coated with anti-fog coating (Example 4) can remain fog-free for 30 minutes at 2 cm above a constant temperature 60°C water bath, demonstrating the good anti-fog ability of the coating.

[0092] Hydrophilic coatings are currently a mainstream anti-fog material and have broad application prospects in medical endoscopes. The coating's high transparency allows it to be applied to endoscope lenses without affecting their normal operation. Furthermore, the coating's high adhesion and the antibacterial properties of magnesium ions impart excellent adhesion and antibacterial properties to endoscope lenses, preventing them from falling off during use.

[0093] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A method for preparing an anti-fog coating, characterized in that: The following steps are involved: Dissolving hydroxyethyl methacrylate and phosphotungstic acid in a mixed solution of water and an organic solvent, adding an initiator, stirring, and polymerizing to obtain a polymer solution; Dissolving a hydrophilic zwitterion, hydroxyethyl methacrylate, and magnesium chloride in water, adding a crosslinking agent and an initiator, and stirring to obtain a monomer solution; The polymer solution and the monomer solution are mixed, stirred, and spin-coated on a substrate, and then dried to obtain the anti-fog coating.

2. The method for preparing the anti-fog coating according to claim 1, wherein: The mass ratio of the hydroxyethyl methacrylate to phosphotungstic acid is (8-12):(10-14).

3. The method for preparing the anti-fog coating according to claim 1, wherein: The hydrophilic zwitterion is 2-methacryloyloxyethyl phosphorylcholine.

4. The method for preparing the anti-fog coating according to claim 3, wherein: The mass ratio of the 2-methacryloyloxyethyl phosphorylcholine to magnesium chloride is (1-2):0.

1.

5. The method for preparing the anti-fog coating according to claim 1, wherein: The mass ratio of the polymer solution to the monomer solution is 1-3:

1.

6. The method for preparing the anti-fog coating according to claim 1, wherein: When the hydrophilic zwitterion, hydroxyethyl methacrylate and magnesium chloride are dissolved in water, the mass ratio of hydroxyethyl methacrylate to the hydrophilic zwitterion is (1-2):(0.05-0.1).

7. The method for preparing the anti-fog coating according to claim 1, wherein: The initiator includes one of benzoyl peroxide, lauroyl peroxide or azobisisobutyronitrile.

8. The method for preparing the anti-fog coating according to claim 1, wherein: The mass ratio of the crosslinking agent to the initiator is (1-1.1):

1.

9. The method for preparing the anti-fog coating according to claim 1, wherein: When preparing the anti-fog coating, the drying temperature is 60-80° C. and the drying time is 12-36 hours.

10. An application of an anti-fog coating prepared by the method according to any one of claims 1 to 9, characterized in that: The anti-fog coating is used for anti-fog modification of medical endoscope lenses.

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