A coating for mouth mirror and preparation method thereof

Abstract

The present invention relates to the technical field of glass surface treatment, and in particular to a coating for a mouth mirror and a preparation method thereof. The coating adopts modified polypropylene imine as a main component, and the polyethylene imine is modified by polydopamine sulfonate and / or catechol, lysine, and then coated on the surface of the mouth mirror. The prepared coating is not only highly hydrophilic and has good anti-fogging properties, but also can play an antibacterial effect after being coated on the mouth mirror, thereby reducing the risk of bacterial infection. The prepared coating has a better combination effect with the mirror surface, so it has better durability and wear resistance, and can maintain a longer anti-fogging effect.

Description

Technical Field

[0001] The invention relates to the technical field of glass surface treatment, and in particular to a coating for a mouth mirror and a preparation method thereof. Background Art

[0002] The mouth mirrors currently used in clinical and teaching are disposable and have no anti-fogging and self-cleaning functions. When the mouth mirror is exposed to an environment with a large temperature difference, the mirror surface is prone to fogging, making it difficult for doctors or users to see the internal situation of the oral cavity, affecting the accuracy of diagnosis and treatment. In medical surgery or precision operations, after being placed in the mouth, the high humidity of the oral gas during exhalation or the debris and moisture during drilling and grinding of the tooth body can cause the mirror surface to fog or become unclear, affecting the operation, increasing the risk of operation, and even causing medical accidents. Fogging of the mouth mirror requires additional time and measures to remove the fog, such as using anti-fogging agents, wiping or heating, which will increase the complexity and time required for the workflow. For patients, fogging of the mouth mirror may require longer operation to wait for the fog to dissipate, reducing the comfort of the visit. Frequent wiping and handling may damage the surface of the mouth mirror, affecting its durability and service life. Fogging will significantly reduce the light transmittance, which will interfere with the inspection process that relies on light, affecting the imaging quality and accuracy.

[0003] There are two main approaches to solving the fogging problem. First, the generation of fog can be reduced by adjusting the environment in which the substrate is located, such as temperature and humidity. For example, in some laboratories equipped with expensive optical instruments, equipment is usually used to maintain constant temperature and humidity to prevent fogging on the glass surface. However, the application of this method is limited, the cost is high, and it is not suitable for large-scale promotion. Another method is to modify the surface of the substrate, mainly including hydrophobic modification and hydrophilic modification. Hydrophobic modification is to change the properties of the substrate surface so that it has the ability to repel water droplets, thereby reducing the adhesion of water molecules. Since water droplets will roll off the surface due to gravity, hydrophobic coatings have advantages in anti-fogging durability. However, only when the water droplets reach a certain size (about 10 microns) can they be removed by rolling, so hydrophobic coatings inevitably have an induction anti-fogging period, although this time may be short, it is still unacceptable in some application scenarios. Hydrophilic anti-fog coatings prevent the formation of fog by allowing condensed water molecules to diffuse rapidly to form a thin film. This coating does not have the inductive anti-fogging period problem of hydrophobic coatings.

[0004] CN111057998A discloses a super-hydrophilic anti-fog coating and its preparation method and application. The coating is composed of TiO2 with photocatalytic activity and doping elements, wherein the doping elements include metal elements and / or non-metallic elements. The present invention reduces its bandgap width by metal and / or non-metal doping of TiO2 with photocatalytic properties, thereby achieving visible light-induced super-hydrophilic anti-fog; the element-doped TiO2 super-hydrophilic anti-fog coating provided by the invention has the advantages of good bonding force, high transparency, long anti-fog time, good anti-fog effect, etc. The contact angle between the obtained coating surface and water is less than 5°, and the super-hydrophilicity is still good after being placed for 3 months. The coating and the wear pin wrapped with dust-free cloth with a diameter of 10 mm are rubbed 500 times under the friction conditions of a load of 1 kg and a stroke of 5 mm. The contact angle with water is still less than 10°, and the light transmittance is 85-92%. At the same time, the preparation method is simple and easy, with high controllability, low cost, and can be mass-produced, and has good application prospects in the field of transparent substrate anti-fog.

[0005] CN116102977A provides a transparent hydrophilic anti-fog coating with silicon-doped carbonized polymer dots as building blocks and a preparation method thereof, which belongs to the technical field of hydrophilic anti-fog coating preparation. The invention firstly prepares polyamino oligosiloxane MAOS by hydrothermal method with 3-aminopropyltriethoxysilane as raw material and tetramethylammonium hydroxide as catalyst, and then reacts with ethylenediaminetetraacetic acid to prepare Si-CPDs, and then adds ethylene oxide, γ-glycidyloxypropyltrimethoxysilane GPTMS, curing agent and leveling agent, and applies the coating solidified liquid obtained after aging on the substrate, and forms a Si-O-Si cross-linked network structure after thermal curing, thereby obtaining a transparent hydrophilic anti-fog coating. The coating material has good film-forming properties, and the introduction of inorganic silicon oxide (from MAOS and GPTMS) gives the coating a high surface hardness; the introduction of hydrophilic groups (from the hydroxyl groups obtained by the ring-opening reaction of ethylene oxide and amino groups) gives the coating a hydrophilic anti-fog function.

[0006] Hydrophilic anti-fog coatings can promote the rapid spreading of water droplets on the surface of materials into a water film to prevent fogging. In order to make transparent materials such as glass have better anti-fog performance, hydrophilic modification of their surfaces is a direct, simple and effective method. However, due to the limitations of the preparation method, current anti-fog coatings generally have the problems of poor anti-fog durability, poor water resistance, poor weather resistance and poor wiping resistance. Therefore, the research and development of super-hydrophilic coatings with long-term anti-fog performance is the development direction of today's anti-fog technology. It is of great significance to research and develop super-hydrophilic anti-fog coatings with high hardness, high wear resistance and scratch resistance. Summary of the invention

[0007] In view of the above-mentioned defects in the prior art, the technical problem to be solved by the present invention is to provide a coating for a mouth mirror and a preparation method thereof.

[0008] Traditional petrochemical polymers, such as polyether, polyethylene, polyacrylate, polyacrylamide and polymethacrylate, have been widely used in the field of polymer coatings. These materials have become preferred materials for manufacturing anti-fog coatings due to their excellent processability, good elasticity and high transparency. In addition, the cost of these raw materials is relatively low, so that they can be produced and applied on a large scale. The present invention provides a hydrophilic anti-fog coating, which uses modified polyethyleneimine as the main component, grafts catechol through Michael addition, and then introduces lysine to react with polyethyleneimine for modification, and polydopamine sulfonate compounding, wherein lysine can react with polyethyleneimine through Michael addition and Schiff base, and can also interact with catechol groups to produce covalent bonds. The sulfonic acid group of polydopamine sulfonate and the catechol group of catechol synergistically enhance hydrophilicity, and compounding makes the functional groups on the coating surface more evenly distributed, increasing the spreadability and wettability of water on the surface. Since polyethyleneimine is rich in amine groups in its molecular structure and has a certain viscosity, these amine groups can form hydrogen bonds with water molecules, making it hydrophilic. By grafting catechol groups on polyethyleneimine, it has better adhesion, and the catechol groups can destroy the cell walls and cell membranes of bacteria, increase the permeability of the cell membrane, cause leakage of intracellular substances, affect the normal metabolism and protein synthesis of bacteria, and thus play an antibacterial role. Polyethyleneimine can promote bacterial adhesion through electrostatic attraction. Due to the uneven charge caused, the attached bacteria are destroyed and thus have antibacterial properties. The lysine side chain contains amino groups, which can interact with the negatively charged components of the bacterial cell wall, thereby affecting the integrity of the bacterial cell wall and causing bacterial death. As a result, the modified polyethyleneimine has strong antibacterial properties. Therefore, the prepared coating is not only highly hydrophilic and anti-fogging, but also can play an antibacterial effect after being applied to the mouth mirror, thereby reducing the risk of bacterial infection. Since the modified polyethyleneimine has improved adhesion, the prepared coating combines better with the mirror surface, so it has better durability and wear resistance, and can maintain the anti-fog effect longer.

[0009] To achieve the above object, the present invention provides a method for preparing a coating for a mouth mirror, comprising the following steps:

[0010] S1, dissolving polydopamine sulfonate and / or catechol and polyethyleneimine in phosphate buffer, adding lysine after stirring to dissolve, and continuing to stir to obtain a modified polyethyleneimine solution;

[0011] S2. Clean the mouth mirror and blow dry it, apply the polyethyleneimine solution on the surface of the mouth mirror, and then dry it to obtain the coating for the mouth mirror.

[0012] Furthermore, the mass ratio of the polydopamine sulfonate, polyethyleneimine and lysine is 1-4:1-2:2-4.

[0013] Furthermore, the mass ratio of catechol, polyethyleneimine and lysine is 1-4:1-2:2-4.

[0014] Furthermore, the mass ratio of the polydopamine sulfonate, catechol, polyethyleneimine and lysine is 0.5-2:0.5-2:1-2:2-4.

[0015] Furthermore, the pH of the phosphate buffer is 8.5-8.8, and the concentration is 0.01 mmol / L.

[0016] Furthermore, the stirring and dissolving time is 2 to 3 hours.

[0017] Furthermore, the stirring time is continued for 10 to 16 hours.

[0018] Furthermore, the concentration of the modified polyethyleneimine solution is 20-50 g / L.

[0019] Furthermore, the drying temperature ranges from 30 to 50°C.

[0020] The present invention also provides a coating for a mouth mirror, which is prepared by the above method and application of the coating in the field of medical devices.

[0021] Beneficial effects of the present invention:

[0022] Compared with the prior art, the coating for the mouth mirror prepared by the present invention is not only highly hydrophilic and has good anti-fogging properties, but also has an antibacterial effect after being applied to the mouth mirror, thereby reducing the risk of infection. The prepared coating has a better combination effect with the mirror surface, so it has better durability and wear resistance, and can maintain a longer anti-fogging effect. DETAILED DESCRIPTION

[0023] Polyethyleneimine, Mw=5000kDa, Guangdong Wengjiang Chemical Reagent.

[0024] Polydopamine sulfonate is prepared by the following method: 2 mL of 30% ammonia water, 40 mL of anhydrous ethanol and 90 mL of water are stirred at room temperature for 30 min. A dopamine hydrochloride solution with a mass concentration of 0.05 g / mL is added to the above solution and reacted for 24 h to obtain a polydopamine nanoparticle dispersion. Take 2 mL of the polydopamine nanoparticle dispersion, add 16 mL of acetone under stirring, and let it stand for sedimentation after the addition is completed. After sedimentation for 10 min, the precipitate is collected by low-speed centrifugation (500 r / min, 5 min), the supernatant is removed, the precipitate is washed with acetone 3 times and dried naturally to obtain polydopamine nanoparticles. 1.2 g of polydopamine nanoparticles are added to 200 mL of Tris buffer with a pH of 8.5, and then 0.5 g of sodium 3-mercapto-1-propanesulfonate is added. After stirring at 60°C for 9 h, the precipitate is separated by centrifugation, washed with ethanol and then water, and dried.

[0025] Staphylococcus aureus, CGMCC1.282, China General Microbiological Culture Collection Center.

[0026] Candida albicans, CICC1965, China Industrial Microbiology Culture Collection Center.

[0027] Example 1

[0028] A method for preparing a coating for a mouth mirror comprises the following steps, measured in parts by weight:

[0029] S1. Dissolve 1 part of catechol and 1 part of polyethyleneimine in 0.01mmol / L, pH=8.5 phosphate buffer, stir for 2h to dissolve, then add 2 parts of lysine, continue stirring for 12h to obtain a modified polyethyleneimine solution with a concentration of 30g / L;

[0030] S2. Clean the mouth mirror and blow dry it, apply the polyethyleneimine solution on the surface of the mouth mirror, and dry it at 45° C. to obtain the coating for the mouth mirror.

[0031] Example 2

[0032] A method for preparing a coating for a mouth mirror comprises the following steps, measured in parts by weight:

[0033] S1. Dissolve 1 part of catechol and 2 parts of polyethyleneimine in 0.01mmol / L, pH=8.5 phosphate buffer, stir for 2h to dissolve, then add 2 parts of lysine, continue stirring for 12h to obtain a modified polyethyleneimine solution with a concentration of 30g / L;

[0034] S2. Clean the mouth mirror and blow dry it, apply the polyethyleneimine solution on the surface of the mouth mirror, and dry it at 35°C to obtain the coating for the mouth mirror.

[0035] Example 3

[0036] A method for preparing a coating for a mouth mirror comprises the following steps, measured in parts by weight:

[0037] S1. Dissolve 2 parts of catechol and 1 part of polyethyleneimine in 0.01mmol / L, pH=8.5 phosphate buffer, stir for 2h to dissolve, then add 2 parts of lysine, continue stirring for 12h to obtain a modified polyethyleneimine solution with a concentration of 30g / L;

[0038] S2. Clean the mouth mirror and blow dry it, apply the polyethyleneimine solution on the surface of the mouth mirror, and dry it at 35°C to obtain the coating for the mouth mirror.

[0039] Example 4

[0040] A method for preparing a coating for a mouth mirror comprises the following steps, measured in parts by weight:

[0041] S1. Dissolve 1 part of catechol and 1 part of polyethyleneimine in 0.01mmol / L, pH=8.5 phosphate buffer, stir for 2h to dissolve, then add 3 parts of lysine, continue stirring for 12h to obtain a modified polyethyleneimine solution with a concentration of 30g / L;

[0042] S2. Clean the mouth mirror and blow dry it, apply the polyethyleneimine solution on the surface of the mouth mirror, and dry it at 35°C to obtain the coating for the mouth mirror.

[0043] Example 5

[0044] A method for preparing a coating for a mouth mirror comprises the following steps, measured in parts by weight:

[0045] S1. Dissolve 1 part of catechol and 1 part of polyethyleneimine in 0.01mmol / L, pH=8.5 phosphate buffer, stir for 2h to dissolve, then add 4 parts of lysine, continue stirring for 12h to obtain a modified polyethyleneimine solution with a concentration of 30g / L;

[0046] S2. Clean the mouth mirror and blow dry it, apply the polyethyleneimine solution on the surface of the mouth mirror, and dry it at 35°C to obtain the coating for the mouth mirror.

[0047] Example 6

[0048] A method for preparing a coating for a mouth mirror comprises the following steps, measured in parts by weight:

[0049] S1. Dissolve 1 part of polydopamine sulfonate and 1 part of polyethyleneimine in 0.01mmol / L, pH=8.5 phosphate buffer, stir for 2h to dissolve, then add 2 parts of lysine, continue stirring for 12h to obtain a modified polyethyleneimine solution with a concentration of 30g / L;

[0050] S2. Clean the mouth mirror and blow dry it, apply the polyethyleneimine solution on the surface of the mouth mirror, and dry it at 45° C. to obtain the coating for the mouth mirror.

[0051] Example 7

[0052] A method for preparing a coating for a mouth mirror comprises the following steps, measured in parts by weight:

[0053] S1, dissolving 0.5 parts of polydopamine sulfonate, 0.5 parts of catechol and 1 part of polyethyleneimine in 0.01mmol / L, pH=8.5 phosphate buffer, stirring for 2h to dissolve, adding 2 parts of lysine, and continuing to stir for 12h to obtain a modified polyethyleneimine solution with a concentration of 30g / L;

[0054] S2. Clean the mouth mirror and blow dry it, apply the polyethyleneimine solution on the surface of the mouth mirror, and dry it at 45° C. to obtain the coating for the mouth mirror.

[0055] Comparative Example 1

[0056] A method for preparing a coating for a mouth mirror comprises the following steps, measured in parts by weight:

[0057] S1. Dissolve 1 part of polyethyleneimine in 0.01mmol / L, pH=8.5 phosphate buffer, and stir for 2h to obtain a polyethyleneimine solution with a concentration of 30g / L;

[0058] S2. Clean the mouth mirror and blow dry it, apply the polyethyleneimine solution on the surface of the mouth mirror, and dry it at 35°C to obtain the coating for the mouth mirror.

[0059] Comparative Example 2

[0060] A method for preparing a coating for a mouth mirror comprises the following steps, measured in parts by weight:

[0061] S1. Dissolve 1 part of catechol and 1 part of polyethyleneimine in 0.01mmol / L, pH=8.5 phosphate buffer, and stir for 2h to obtain a modified polyethyleneimine solution with a concentration of 30g / L.

[0062] S2. Clean the mouth mirror and blow dry it, apply the modified polyethyleneimine solution on the surface of the mouth mirror, and dry it at 35° C. to obtain the coating for the mouth mirror.

[0063] Comparative Example 3

[0064] A method for preparing a coating for a mouth mirror comprises the following steps, measured in parts by weight:

[0065] S1. Dissolve 1 part of polyethyleneimine in 0.01mmol / L, pH=8.5 phosphate buffer, stir for 2h to dissolve, then add 2 parts of lysine, continue stirring for 12h to obtain a modified polyethyleneimine solution with a concentration of 30g / L;

[0066] S2. Clean the mouth mirror and blow dry it, apply the polyethyleneimine solution on the surface of the mouth mirror, and dry it at 35°C to obtain the coating for the mouth mirror.

[0067] Test Example 1

[0068] The coatings prepared in the embodiments and control examples were tested for water contact angles and compared with the mouth mirrors that were not treated with the coating. Two standard methods were used to test the anti-fogging of the coating: the hot steam method and the cold and warm method. Hot steam anti-fogging test: First, the coated and untreated mouth mirrors were placed on a beaker filled with 80°C hot water for 1 minute. During this process, the formation of fog on the slide was observed, and the fogging conditions were recorded. Cold and warm anti-fogging test: Black A4 paper with text was pasted on the surface of the coated and untreated mouth mirrors with double-sided tape. Then, the slides were placed in a refrigerator preset at -20°C for 1 hour. After taking it out, it was placed in a room temperature environment with a relative humidity of 40%, the formation of fog was observed, and the fogging on the mouth mirror was recorded. The specific results are shown in Table 1.

[0069] Table 1 Water contact and anti-fog test results of mouth mirror coating

[0070] Experimental protocol Water contact angle / ° Hot steam anti-fog test Cold and warm anti-fog test Untreated mouth mirror 37.2 Fogging Fogging Example 1 4.2 No fogging No fogging Example 2 10.1 No fogging No fogging Example 3 8.9 No fogging No fogging Example 4 9.2 No fogging No fogging Example 5 10.4 No fogging No fogging Example 6 5.3 No fogging No fogging Example 7 3.0 No fogging No fogging Comparative Example 1 12.5 No fogging No fogging Comparative Example 2 9.5 No fogging No fogging Comparative Example 3 9.7 No fogging No fogging

[0071] As can be seen from Table 1, the coating prepared by the present invention has good hydrophilicity, so when a water drop contacts the coating surface, when the water contact angle approaches 0° (super-hydrophilic state), the water drop will gradually spread on the surface of the substrate to form a layer of water film, which will weaken the refraction and scattering of light, and fog will not be generated. Compared with Examples 1 to 7, the addition ratio of each raw material is different, resulting in different water contact angles on the coating surface, and from the experimental data, it can be seen that the proportional water contact angle in Example 7 is the smallest, which means that the hydrophilicity is also the best, so the dosage ratio in Example 7 is the best. In Example 6, although the sulfonic acid group in polydopamine sulfonate has super-hydrophilicity, when used alone, due to its strong intramolecular cohesion, it is difficult for the sulfonic acid group to be evenly distributed on the coating surface, resulting in a high water contact angle of 5.3°. This intermolecular action weakens the ability of water to form a continuous water film on the surface, and fails to fully demonstrate its expected super-hydrophilic effect. In the compounding scheme of Example 7, the sulfonic acid group of polydopamine sulfonate and the catechol group of catechol form a synergistic effect at the molecular level, significantly improving the hydrophilicity of the coating, and reducing the water contact angle to 3.0 °. This synergistic effect comes from the extremely strong hydrophilicity of the sulfonic acid group and the good distribution of the catechol group. The sulfonic acid group strongly acts on the water molecule through hydrogen bonds, making it very easy to form a water film on the surface, and the catechol group reduces the intermolecular cohesion through the π-π stacking and hydrogen bonding with the sulfonic acid group, so that the hydrophilic group is evenly distributed on the coating surface. This synergistic effect increases the surface free energy of the coating, improves the spreadability and wettability of water, thereby significantly reducing the water contact angle, and achieving ideal super-hydrophilicity, so the water contact angle of Example 7 is the minimum. And the embodiment is compared with Reference Examples 1 to 3, and polyethyleneimine is modified to varying degrees, and the hydrophilicity of the coating is enhanced, but the coating hydrophilicity in the embodiment is better, and the coating surface shows better wettability. From the anti-fogging test, we can see that the mouth mirror with modified coating will not fog in both the hot steam method and the cold and warm method, while the untreated mouth mirror will fog in both methods. This is because the surface of the modified mouth mirror contains a super-hydrophilic coating, which can make the water molecules condensed on the surface of the substrate form a thin water film, which will not refract and scatter the light, so it will not generate fog; while the untreated mouth mirror has poor surface wettability, and the water vapor condenses into small water droplets on the surface when it encounters cold, thus fogging occurs.

[0072] Test Example 2

[0073] In order to evaluate the adhesion of the coating, the coating interface bonding performance was tested using the hundred-grid method with reference to the standard "GB / T 9286-2021 Paint and Varnish Cross-cut Test". The operation steps are as follows: Place the coated mirror flat on a flat workbench, hold a hundred-grid knife, ensure that the blade is perpendicular to the coating surface during the cutting process, and draw 10 equally spaced horizontal lines on the mirror at a speed of 20-50mm / s. Rotate the mirror 90°, and use the hundred-grid knife again to draw 10 equally spaced vertical lines perpendicular to the horizontal lines on the film surface to form a 10×10 square grid. Take a piece of transparent tape and stick it on the square grid in a direction parallel to the grid lines, and make sure that the tape is firmly attached. After it is firmly attached, gently peel off a corner of the tape and tear off the tape smoothly at an angle of 60°. Use a magnifying glass to observe the grid damage on the surface of the mirror and rate the degree of damage to the coating.

[0074] Table 2 Adhesion performance test results of mouth mirror coating

[0075] Experimental protocol level Example 1 Level 0 Example 2 Level 0 Example 3 Level 0 Example 4 Level 0 Example 5 Level 0 Example 6 Level 0 Example 7 Level 0 Comparative Example 1 Level 2 Comparative Example 2 Level 0 Comparative Example 3 Level 2

[0076] As can be seen from Table 2, the coating prepared by the embodiment has better adhesion, which may be due to the coating in the embodiment using modified polyethyleneimine as the main component, grafting catechol by Michael addition, and then introducing lysine to react with polyethyleneimine for modification, wherein lysine can react with polyethyleneimine by Michael addition and Schiff base reaction, and can also interact with catechol groups to produce covalent bonds. Since polyethyleneimine is rich in amine groups in its molecular structure and has a certain viscosity, catechol groups can be grafted onto polyethyleneimine, and catechol groups can be effectively attached to various substrate surfaces through hydrogen bonds, metal coordination, π-π / π-cations, thiol reduction and other interactions, so the coating has better adhesion, and since the adhesion of the modified polyethyleneimine is improved, the prepared coating has a better combination effect with the mirror surface, so the durability and wear resistance are better, and the anti-fog effect can be maintained for a longer time. However, the polyethyleneimine in Comparative Examples 1 and 3 is not modified by catechol, and the coating does not have a catechol group, so the adhesion of the coating is poor.

[0077] Test Example 3

[0078] In order to verify the antibacterial activity of the coating, two bacteria were selected: Staphylococcus aureus and Candida albicans. The experimental steps were as follows: the uncoated mouth mirror was used as the blank control group, and the experimental group was the coated mouth mirror. These glass pieces were incubated with a bacterial suspension containing Escherichia coli and Staphylococcus aureus (400 μL, concentration of 10 6CFU / mL) for 1 hour of co-culture. After culture, the bacterial suspension was diluted 100,000 times with PBS solution, and the diluted bacterial solution was inoculated on the culture medium. The culture medium inoculated with bacteria was placed in an incubator at 37°C and continued to be cultured for 24 hours. The plate counting method was used to count the number of colony forming units (CFU) on the culture medium to evaluate the antibacterial effect of the coating. The antibacterial rate (A) was calculated as: A= (A0-A1) / A0*100%. Among them, A0 represents the number of colonies in the control group, and A1 represents the number of colonies in the experimental group.

[0079] Table 3 Antibacterial test results of mouth mirror coating

[0080] Experimental protocol Antibacterial rate of Staphylococcus aureus / % Candida albicans antibacterial rate / % Example 1 95.67 99.78 Example 2 95.43 99.23 Example 3 94.68 99.45 Example 4 94.67 99.34 Example 5 95.55 98.78 Example 6 94.98 99.34 Example 7 95.87 99.89 Comparative Example 1 65.78 68.91 Comparative Example 2 76.72 78.76 Comparative Example 3 75.67 80.12

[0081] Staphylococcus aureus ( Staphylococcus aureus ) is a gram-positive bacterium that can cause maxillofacial infections and has a tendency to increase due to the misuse of antibiotics. If a physician is exposed to this bacterium during treatment, they may be at risk for skin infection, especially if there are wounds or broken skin. In addition, if Staphylococcus aureus enters the bloodstream, it may cause more serious infections such as bacteremia or sepsis. Candida species ( Candida species , including Candida albicans ( Candida albicans ), etc., which can cause oral candidiasis under certain conditions, especially in patients with low immunity or long-term use of antibiotics. Doctors who are infected with Candida may suffer from skin or mucous membrane infections, such as paronychia and cutaneous candidiasis. In hospital environments, Candida may also be spread through contact, leading to an increase in hospital infections. The coatings prepared by the present invention have good antibacterial properties, thereby reducing the risk of infection. Compared with control examples 1 to 3, the antibacterial rate of the embodiment is higher. This may be because in the embodiment, catechol is grafted by Michael addition, and then lysine is introduced to react with polyethyleneimine for modification. The catechol group can destroy the cell wall and cell membrane of bacteria, increase the permeability of the cell membrane, cause leakage of intracellular substances, affect the normal metabolism and protein synthesis of bacteria, and thus play an antibacterial role. Polyethyleneimine can promote bacterial adhesion through electrostatic attraction. Due to the uneven charge caused, the attached bacteria are destroyed and thus have antibacterial properties. The lysine side chain contains an amino group, which can interact with the negatively charged components of the bacterial cell wall, thereby affecting the integrity of the bacterial cell wall and causing bacterial death. It can achieve antibacterial properties through multiple mechanisms and multiple pathways, resulting in the modified polyethyleneimine having strong antibacterial properties. Therefore, the prepared coating is not only highly hydrophilic and anti-fogging, but also can have an antibacterial effect after being applied to the mouth mirror. In Control Example 1, polyethyleneimine was not modified, while Control Examples 2 and 3 were modified with catechol and lysine, respectively. The antibacterial effects were not as good as those of Examples 1, 6, and 7.

[0082] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for preparing a coating for a mouth mirror, characterized in that: The steps include: S1. Dissolve polydopamine sulfonate, catechol and polyethyleneimine in phosphate buffer, stir for 2-3 hours until dissolved, then add lysine, and continue stirring for 10-16 hours to obtain a modified polyethyleneimine solution; the mass ratio of polydopamine sulfonate, catechol, polyethyleneimine and lysine is 0.5-2:0.5-2:1-2:2-4; S2. Clean the mouth mirror and blow dry it, apply 20-50 g / L modified polyethyleneimine solution on the surface of the mouth mirror, and dry it at 30-50°C to obtain the coating for the mouth mirror.

2. The method for preparing a coating for a mouth mirror according to claim 1, characterized in that: The pH of the phosphate buffer is 8.5-8.

8.

3. A coating for a mouth mirror, characterized in that: Prepared by the method according to any one of claims 1 to 2.

4. Use of the coating as claimed in claim 3 in the field of medical devices.