A moisturizing protein-based contact lens and a method of making the same

Abstract

This invention belongs to the field of contact lens technology, and provides a moisturizing protein-based contact lens and its preparation method. The preparation method includes the following steps: mixing a silk fibroin solution and a hyaluronic acid-binding protein solution to obtain a protein mixture solution; mixing a hydrophilic modification component, an oxygen-permeable modification component, and water to obtain a composite modifier; mixing the protein mixture solution, the composite modifier, and a crosslinking agent to obtain a pre-crosslinked mixture; molding the pre-crosslinked mixture and performing gradient crosslinking, followed by sequential soaking in buffer solution, rinsing, and sterilization to obtain the moisturizing protein-based contact lens. The contact lens of this invention uses protein as the main component, does not rely on silicon-based substances or harmful crosslinking agents, and possesses high biocompatibility, high oxygen permeability, suitable mechanical properties, and controllable degradation.

Description

Technical Field

[0001] This invention relates to the field of contact lens technology, and in particular to a moisturizing protein-based contact lens and its preparation method. Background Technology

[0002] Contact lenses are important medical devices for correcting vision, improving the appearance of the eyes, and assisting in eye treatment. The material properties of these lenses directly determine their safety, comfort, and durability. Currently, most mainstream contact lens materials on the market are synthetic polymers, such as polymethyl methacrylate (PMMA) and siloxane polymers. While these materials meet basic optical and mechanical requirements, they suffer from limited biocompatibility and difficulties in balancing oxygen permeability and hydrophilicity. Long-term wear can easily lead to discomfort such as dry eyes, redness, and allergies. Furthermore, they are difficult to biodegrade after disposal, causing environmental pollution.

[0003] To address the aforementioned shortcomings, existing technologies have explored the use of natural biomaterials to fabricate contact lenses, with protein-based materials becoming a research hotspot due to their excellent biocompatibility and cell affinity. For example, existing technologies utilize single-protein materials such as collagen and silk fibroin to fabricate contact lenses; however, single-protein materials suffer from insufficient mechanical strength, rapid degradation under physiological conditions, and poor light transmittance, failing to meet the practical needs of contact lens use. Other technologies improve the stability of protein materials by adding cross-linking agents, but traditional cross-linking agents may disrupt the natural structure of proteins, reducing biocompatibility, and are difficult to balance with oxygen permeability, mechanical properties, and degradability. Furthermore, some technologies introduce silicon-based substances to enhance oxygen permeability, but this further reduces the material's biocompatibility and degradability, limiting its application in short-term wear and medical fields.

[0004] Therefore, it is of great significance to develop a moisturizing protein-based contact lens with protein as the main component, which does not rely on silicon-based substances and harmful cross-linking agents, and has high biocompatibility, high oxygen permeability, suitable mechanical properties and controllable degradation, as well as its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide a moisturizing protein-based contact lens and its preparation method, thereby solving the problems of poor biocompatibility, insufficient oxygen permeability, poor mechanical properties and complex preparation process in the prior art.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing moisturizing protein-based contact lenses, the method comprising the following steps: 1) Mix the silk fibroin solution and the hyaluronic acid-bound protein solution to obtain a protein mixture solution; 2) Mix the hydrophilic modifier, the oxygen-permeable modifier, and water to obtain a composite modifier; 3) Mix the protein mixture, composite modifier, and crosslinking agent to obtain a pre-crosslinked mixture; 4) After the pre-crosslinked mixture is injected into the mold, it is subjected to gradient crosslinking, followed by soaking in buffer solution, rinsing and sterilization treatment in sequence to obtain moisturizing protein-based contact lenses.

[0007] Preferably, in step 1), the solvent for the silk fibroin solution is an acetic acid solution with a pH of 3.5 to 4.5 and a silk fibroin concentration of 20 to 30 mg / mL. The solvent for the hyaluronic acid-binding protein solution is water, and the concentration of hyaluronic acid-binding protein is 5~20 mg / mL.

[0008] Preferably, in step 1), the mass ratio of silk fibroin to hyaluronic acid-binding protein is 1~6:4~9; The mixing is ultrasonic mixing, with a power of 200~300W and a mixing time of 10~20min.

[0009] Preferably, in step 2), the hydrophilic modifying component is low molecular weight hyaluronic acid with a molecular weight of 100~200kDa, and the oxygen permeability modifying component is trehalose or agarose.

[0010] Preferably, in step 2), the mixing temperature is 30~40℃, the mixing speed is 100~200rpm, and the mixing time is 20~30min; The mass ratio of the hydrophilic modified component, the oxygen-permeable modified component, and water is 2~5:1~2:15~30.

[0011] Preferably, in step 3), the mass ratio of the protein mixture solution, the composite modifier, and the crosslinking agent is 60~90:5~30:1~6, and the crosslinking agent is proanthocyanidins and / or tannic acid.

[0012] Preferably, in step 3), the mixing speed is 80~120 rpm and the mixing time is 30~60 min.

[0013] Preferably, in step 4), the gradient crosslinking includes a first crosslinking and a second crosslinking. The temperature of the first crosslinking is 5~10℃ and the time of the first crosslinking is 30~60min. The temperature of the second crosslinking is 20~25℃ and the time of the second crosslinking is 4~8h.

[0014] Preferably, in step 4), the soaking time in the buffer solution is 2-4 hours, and the buffer solution is a phosphate buffer solution; The rinsing reagent is water, and the rinsing is performed 3 to 5 times, with each rinsing lasting 10 to 15 minutes. The sterilization temperature is 120~125℃, and the sterilization time is 30~60 minutes.

[0015] The present invention also provides a method for preparing moisturizing protein-based contact lenses, resulting in moisturizing protein-based contact lenses.

[0016] The beneficial effects of this invention are: This invention uses a protein mixture as the main component, selecting silk fibroin protein with excellent biocompatibility, supplemented by natural cross-linking agents and composite modifiers, without adding any silicon substances or harmful chemical synthetic reagents. The material has excellent biocompatibility and strong affinity with eye tissue, which can significantly reduce discomfort symptoms such as dryness and allergies caused by long-term wear, improve wearing comfort and safety, and the material is biodegradable, so it will not cause pollution to the environment after disposal.

[0017] This invention optimizes the compounding ratio of protein mixtures and combines the synergistic effect of composite modifiers to improve the hydrophilicity and water-locking capacity of materials while optimizing the pore structure of the materials, achieving high oxygen permeability with an oxygen permeability coefficient of 120~180 barrer. This meets the oxygen requirements of the cornea and avoids problems such as redness, swelling, and pain caused by corneal hypoxia. At the same time, through a two-step natural cross-linking process, a stable cross-linking network is formed, giving the contact lenses appropriate mechanical strength, with a tensile strain of not less than 50%, making them less prone to breakage and deformation, and with a service life of 1~3 months, thus balancing practicality and durability.

[0018] The preparation method of this invention is simple, requiring no complex equipment or harsh reaction conditions. The two-step crosslinking process can effectively control the degree of crosslinking and avoid damage to the protein structure. At the same time, post-processing steps such as centrifugation and rinsing can ensure product purity and safety. The entire preparation process is easy to scale up for industrial production, with low production costs. Compared with existing synthetic polymer contact lenses and single protein contact lenses, it has stronger market competitiveness. Detailed Implementation

[0019] This invention provides a method for preparing moisturizing protein-based contact lenses, the method comprising the following steps: 1) Mix the silk fibroin solution and the hyaluronic acid-bound protein solution to obtain a protein mixture solution; 2) Mix the hydrophilic modifier, the oxygen-permeable modifier, and water to obtain a composite modifier; 3) Mix the protein mixture, composite modifier, and crosslinking agent to obtain a pre-crosslinked mixture; 4) After the pre-crosslinked mixture is injected into the mold, it is subjected to gradient crosslinking, followed by soaking in buffer solution, rinsing and sterilization treatment in sequence to obtain moisturizing protein-based contact lenses.

[0020] In this invention, in step 1), the solvent for the silk fibroin solution is preferably an acetic acid solution, the pH value of the acetic acid solution is preferably 3.5-4.5, more preferably 3.8-4.4, and even more preferably 4-4.2, and the concentration of the silk fibroin is preferably 20-30 mg / mL, more preferably 22-28 mg / mL, and even more preferably 24-26 mg / mL; The solvent for the hyaluronic acid-binding protein solution is preferably water, and the concentration of the hyaluronic acid-binding protein is preferably 5-20 mg / mL, more preferably 7-18 mg / mL, and even more preferably 10-15 mg / mL.

[0021] In this invention, the ratio of silk fibroin to hyaluronic acid-binding protein can achieve uniformity in the protein structure, taking into account both biocompatibility and mechanical properties, and avoiding the defects of single protein materials.

[0022] In this invention, the pH value of the acetic acid used ensures that the natural structure of collagen and silk fibroin is not damaged, thereby improving the stability of the solution.

[0023] In this invention, in step 1), the mass ratio of silk fibroin to hyaluronic acid-binding protein is preferably 1~6:4~9, more preferably 2~5:5~8, and even more preferably 3~4:6~7. The mixing is preferably ultrasonic mixing, the ultrasonic mixing power is preferably 200~300W, more preferably 220~280W, more preferably 240~260W, and the ultrasonic mixing time is preferably 10~20min, more preferably 12~18min, and more preferably 14~15min.

[0024] In this invention, in step 2), the hydrophilic modification component is preferably low molecular weight hyaluronic acid, the molecular weight of which is preferably 100~200kDa, more preferably 120~180kDa, and even more preferably 150~160kDa. The oxygen permeability modification component is preferably trehalose or agarose.

[0025] In this invention, the combination of the hydrophilic modification component and the oxygen permeability modification component can significantly improve the hydrophilicity and water-locking ability of the material. At the same time, the molecular structure of trehalose optimizes the porosity of the material, improves the oxygen permeability, and reduces the dryness of the eyes when wearing it.

[0026] In this invention, in step 2), the mixing temperature is preferably 30~40℃, more preferably 32~38℃, and even more preferably 34~36℃; the mixing speed is preferably 100~200rpm, more preferably 120~180rpm, and even more preferably 140~160rpm; and the mixing time is preferably 20~30min, more preferably 22~28min, and even more preferably 24~26min. The preferred mass ratio of the hydrophilic modified component, the oxygen-permeable modified component, and water is 2~5:1~2:15~30, more preferably 3~4:1.2~1.8:18~28, and even more preferably 3.2~3.8:1.4~1.6:20~24.

[0027] In this invention, in step 3), the mass ratio of the protein mixture solution, the composite modifier, and the crosslinking agent is preferably 60~90:5~30:1~6, more preferably 65~85:8~26:2~5, and even more preferably 70~80:15~20:3~4. The crosslinking agent is preferably proanthocyanidins and / or tannic acid.

[0028] In this invention, the crosslinking agent can form a stable crosslinking network without destroying the natural structure of the protein, thereby improving the mechanical strength and anti-degradation properties of the material, while further enhancing the biocompatibility and antioxidant capacity of the material. By using a natural crosslinking agent combined with gradient crosslinking, oxygen permeability, moisture retention, mechanical properties and biocompatibility are improved without using silicon components and toxic crosslinking agents.

[0029] In this invention, the crosslinking agent avoids irritating eye tissues compared to silicon-based substances and chemically synthesized crosslinking agents.

[0030] In this invention, in step 3), the mixing speed is preferably 80~120 rpm, more preferably 90~110 rpm, and even more preferably 100~105 rpm, and the mixing time is preferably 30~60 min, more preferably 35~55 min, and even more preferably 40~50 min.

[0031] In this invention, in step 3), the mixture is centrifuged to remove air bubbles and impurities from the system. The centrifugation speed is preferably 3000~5000 rpm, more preferably 3500~4500 rpm, and even more preferably 4000~4200 rpm. The centrifugation time is preferably 10~15 min, more preferably 11~14 min, and even more preferably 12~13 min.

[0032] In this invention, step 4) preferably includes a first crosslinking and a second crosslinking. The temperature of the first crosslinking is preferably 5~10℃, more preferably 6~9℃, and even more preferably 7~8℃. The time of the first crosslinking is preferably 30~60min, more preferably 35~50min, and even more preferably 40~45min. The temperature of the second crosslinking is preferably 20~25℃, more preferably 21~24℃, and even more preferably 22~23℃. The time of the second crosslinking is preferably 4~8h, more preferably 5~7h, and even more preferably 5.5~6h.

[0033] In this invention, the gradient crosslinking can avoid structural inhomogeneity caused by excessively rapid crosslinking reaction, thereby improving the optical performance and mechanical stability of the lens.

[0034] In this invention, in step 4), the soaking time of the buffer solution is preferably 2-4 hours, more preferably 2.5-3.5 hours, and even more preferably 3 hours, and the buffer solution is preferably phosphate buffer solution; The preferred rinsing agent is water, the preferred number of rinsings is 3 to 5, more preferably 4, and the preferred rinsing time for each rinsing is 10 to 15 minutes, more preferably 11 to 14 minutes, and more preferably 12 to 13 minutes. The sterilization temperature is preferably 120~125℃, more preferably 121~124℃, and even more preferably 122~123℃. The sterilization time is preferably 30~60min, more preferably 35~55min, and even more preferably 40~50min.

[0035] The present invention also provides a method for preparing moisturizing protein-based contact lenses, resulting in moisturizing protein-based contact lenses.

[0036] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0037] Example 1

[0038] A silk fibroin solution with a concentration of 25 mg / mL was prepared using acetic acid solution with pH=4.0 as the solvent; a hyaluronic acid-binding protein solution with a concentration of 12 mg / mL was prepared using water as the solvent. The two solutions were mixed according to a ratio of 3:7 between silk fibroin and hyaluronic acid-binding protein and ultrasonically mixed at 250W power for 15 min to obtain a protein mixture solution. Low molecular weight hyaluronic acid (molecular weight of 150kDa), trehalose and water were mixed at a mass ratio of 3.5:1.5:22 at 35℃ and 150rpm for 25 minutes until completely dissolved to obtain a composite modifier. The protein mixture, composite modifier, and proanthocyanidins were stirred at 100 rpm for 45 min at a mass ratio of 75:18:3.5, and then centrifuged at 4000 rpm for 12 min to remove air bubbles and impurities from the system, thus obtaining a pre-crosslinked mixture. The pre-crosslinked mixture is injected into a special mold for contact lenses. It is first crosslinked at 7.5℃ for 42 min, and then crosslinked at 22.5℃ for 5.5 h. After crosslinking, it is soaked in phosphate buffer for 3 h, then rinsed with deionized water 4 times, each time for 12 min. Finally, it is sterilized at 122℃ for 45 min, cooled and removed to obtain moisturizing protein-based contact lenses.

[0039] Example 2

[0040] A silk fibroin solution with a concentration of 20 mg / mL was prepared using acetic acid solution with pH=3.5 as solvent; a hyaluronic acid-binding protein solution with a concentration of 5 mg / mL was prepared using water as solvent. The two solutions were mixed according to a ratio of 1:9 between silk fibroin and hyaluronic acid-binding protein and ultrasonically mixed at 200W power for 20 min to obtain a protein mixture solution. Low molecular weight hyaluronic acid (molecular weight of 100kDa), agarose and water were mixed at a mass ratio of 2:1:15 at 30℃ and 100rpm for 30 minutes until completely dissolved to obtain a composite modifier. The protein mixture, composite modifier, and proanthocyanidins were stirred at 80 rpm for 60 min at a mass ratio of 60:5:1, and then centrifuged at 3500 rpm for 15 min to remove air bubbles and impurities from the system, thus obtaining a pre-crosslinked mixture. The pre-crosslinked mixture is injected into a special mold for contact lenses. It is first crosslinked at 5°C for 60 min, then crosslinked at 20°C for 8 h. After crosslinking, it is soaked in phosphate buffer for 2 h, then rinsed three times with deionized water for 15 min each time. Finally, it is sterilized at 120°C for 60 min, cooled and removed to obtain moisturizing protein-based contact lenses.

[0041] Example 3

[0042] A silk fibroin solution with a concentration of 30 mg / mL was prepared using acetic acid solution with pH=4.5 as solvent; a hyaluronic acid-binding protein solution with a concentration of 20 mg / mL was prepared using water as solvent. The two solutions were mixed according to a ratio of 6:4 between silk fibroin and hyaluronic acid-binding protein and ultrasonically mixed at 300W power for 10 min to obtain a protein mixture solution. Low molecular weight hyaluronic acid (molecular weight of 200kDa), trehalose and water were mixed at a mass ratio of 5:2:30 at 40℃ and 200rpm for 20 minutes until completely dissolved to obtain a composite modifier. The protein mixture, composite modifier, and proanthocyanidins were stirred at 120 rpm for 30 min at a mass ratio of 90:30:6, and then centrifuged at 4500 rpm for 10 min to remove air bubbles and impurities from the system, thus obtaining a pre-crosslinked mixture. The pre-crosslinked mixture is injected into a special mold for contact lenses. It is first crosslinked at 10°C for 30 min, then crosslinked at 25°C for 4 h. After crosslinking, it is soaked in phosphate buffer for 4 h, then rinsed with deionized water 5 times for 10 min each time, and finally sterilized at 125°C for 30 min. After cooling, it is taken out to obtain moisturizing protein-based contact lenses.

[0043] Comparative Example 1

[0044] Compared with Example 1, "trehalose" is removed, while the other steps are the same as in Example 1.

[0045] Comparative Example 2

[0046] Compared to Example 1, the "hyaluronic acid-binding protein solution" was removed, while the other steps were the same as in Example 1.

[0047] Comparative Example 3

[0048] Compared with Example 1, glutaraldehyde was used instead of proanthocyanidins, and the gradient crosslinking was modified to crosslinking at 22.5°C for 6 hours. Other steps were the same as in Example 1.

[0049] The moisturizing protein-based contact lenses obtained in Examples 1-3 and Comparative Examples 1-3 were subjected to the following performance tests, and the performance results are shown in Table 1: Oxygen permeability test: Referring to GB / T 11417.7-2012 "Ophthalmic Contact Lenses - Part 7: Determination of Oxygen Permeability and Transmissibility", an oxygen permeability meter was used to measure the oxygen permeability coefficient (Dk value, unit: barrer) and oxygen transmission rate (Dk / t value) of each sample under conditions of 25℃ and 85% relative humidity. A higher oxygen permeability coefficient indicates better oxygen permeability of the contact lens, and a better ability to meet the oxygen requirements of the cornea.

[0050] Moisturizing performance test: Take each sample, blot the surface moisture with filter paper, and weigh the initial mass (m0). The sample was immersed in phosphate buffer (pH=7.4, simulating the environment of human tears) at 25℃ for 2 hours. After removal, the surface moisture was blotted dry, and the saturated water absorption mass (m1) was weighed. The moisturizing rate was calculated using the formula: Moisturizing rate (%) = (m1 - m0) / m0 × 100%; After the sample has absorbed saturated water, it is placed in an environment of 25℃ and 40% relative humidity. The sample mass is weighed every 1 hour, and the time when the sample mass drops to 1.2 times the initial mass is recorded as the water-locking time (h). The higher the moisturizing rate and the longer the water-locking time, the better the moisturizing performance of the contact lens, which can reduce the dryness of the eyes when wearing it.

[0051] Mechanical property testing: Referring to GB / T 1040.3-2006 "Determination of Tensile Properties of Plastics - Part 3: Test Conditions for Films and Sheets", a universal testing machine was used to cut each sample into strips of 10mm × 50mm. The tensile speed was set to 5mm / min, and the tensile strength (unit: MPa) and tensile strain (unit: %) of the samples were measured. Higher tensile strength indicates stronger resistance to fracture; higher tensile strain indicates better flexibility and less susceptibility to breakage and deformation.

[0052] Biocompatibility testing

[0053] Cytotoxicity test: The extract of each sample (soaked at 25℃ for 24h, extract concentration of 0.1g / mL) was co-cultured with L929 fibroblasts for 24h. Cell viability was determined by MTT assay. Cell viability ≥90% was considered to be non-cytotoxic and biocompatibility was good. Eye irritation test: Select healthy New Zealand white rabbits (3 rabbits per group), and wear each sample on the surface of the rabbit's eyeball for 8 hours a day for 7 consecutive days. Observe whether the rabbit's eyes show irritation symptoms such as redness, swelling, increased secretions, and corneal opacity.

[0054] Table 1. Performance test results of moisturizing protein-based contact lenses obtained in Examples 1-3 and Comparative Examples 1-3

[0055] As shown in Table 1, the moisturizing protein-based contact lenses prepared in Examples 1-3 exhibit excellent performance in all aspects. Their oxygen permeability coefficients are all between 120 and 180 barrers, significantly higher than the 105.4 barrers of the blank control group, fully meeting the oxygen requirements of the cornea. Their moisturizing rate is above 79%, and their water-locking time is above 10 hours, significantly better than the 58.3% moisturizing rate and 4.5 hours water-locking time of the blank control group, effectively alleviating eye dryness during wear. Their tensile strength is between 1.56 and 2.05 MPa, and their tensile strain is above 59%, demonstrating good mechanical properties and resistance to breakage and deformation. Their cell viability is above 94%, indicating excellent biocompatibility and no eye irritation.

[0056] Comparative Example 1, lacking the oxygen permeability modifier, had an oxygen permeability coefficient of only 68.9 barrer, significantly lower than the 155.3 barrer of Example 1. This indicates that the oxygen permeability modifier (trehalose / agarose) effectively optimizes the material's pore structure, significantly improving the oxygen permeability of contact lenses and preventing discomfort caused by corneal hypoxia. Comparative Example 2 used single-protein silk fibroin as the raw material without the addition of hyaluronic acid-binding protein, resulting in a decrease in moisturizing rate to 65.7%, a shortened water-locking time to 7.3 hours, a decrease in tensile strength to 1.03 MPa, a decrease in tensile strain to 38.5%, a decrease in cell viability to 88.2%, and the occurrence of mild eye irritation. This demonstrates that the combined use of silk fibroin and hyaluronic acid-binding protein can synergistically improve the material's moisturizing performance, mechanical properties, and biocompatibility, overcoming the shortcomings of single-protein materials and ensuring the product's wearing comfort and practicality. Comparative Example 3 used a traditional chemical crosslinking agent instead of a natural crosslinking agent and did not employ a gradient crosslinking process, resulting in a cell survival rate of 75.6%, significant eye irritation, and a tensile strain of 42.3%. This indicates that the natural crosslinking agent (proanthocyanidins / tannic acid) used in this invention can ensure biocompatibility without damaging the protein structure, while the gradient crosslinking process can improve the mechanical stability and optical properties of the material, avoiding the defects of traditional crosslinking methods. The blank control group (commercially available synthetic polymer contact lenses) had a longer service life and higher tensile strength, but its oxygen permeability, moisturizing rate, and cell survival rate were all lower than those of Examples 1-3, and it also exhibited mild eye irritation. This demonstrates that the moisturizing protein-based contact lenses prepared in this invention are superior to commercially available products in terms of oxygen permeability, moisturizing properties, biocompatibility, and environmental friendliness, solving the core defects of existing technologies and possessing stronger market competitiveness.

[0057] In summary, the preparation method of the moisturizing protein-based contact lenses described in this invention, through the rational compounding of protein raw materials, the addition of composite modifiers, and the use of natural cross-linking agents and gradient cross-linking processes, produces contact lenses that possess high oxygen permeability, high moisturizing properties, excellent mechanical properties, excellent biocompatibility and biodegradability, are comfortable to wear, safe and environmentally friendly, and have a simple preparation process that is easy to industrialize. Compared with existing technologies and commercially available products, these methods have significant advantages.

[0058] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a moisturizing protein-based contact lens, characterized in that, The preparation method includes the following steps: 1) Mix the silk fibroin solution and the hyaluronic acid-bound protein solution to obtain a protein mixture solution; 2) Mix the hydrophilic modifier, the oxygen-permeable modifier, and water to obtain a composite modifier; 3) Mix the protein mixture, composite modifier, and crosslinking agent to obtain a pre-crosslinked mixture; 4) After the pre-crosslinked mixture is injected into the mold, it is subjected to gradient crosslinking, followed by soaking in buffer solution, rinsing and sterilization treatment in sequence to obtain moisturizing protein-based contact lenses.

2. The method for preparing a moisturizing protein-based contact lens according to claim 1, characterized in that, In step 1), the solvent for the silk fibroin solution is acetic acid solution, the pH value of the acetic acid solution is 3.5~4.5, and the concentration of silk fibroin is 20~30mg / mL; The solvent for the hyaluronic acid-binding protein solution is water, and the concentration of hyaluronic acid-binding protein is 5~20 mg / mL.

3. The method for preparing a moisturizing protein-based contact lens according to claim 2, characterized in that, In step 1), the mass ratio of silk fibroin to hyaluronic acid-binding protein is 1~6:4~9; The mixing is ultrasonic mixing, with a power of 200~300W and a mixing time of 10~20min.

4. The method for preparing a moisturizing protein-based contact lens according to claim 1 or 3, characterized in that, In step 2), the hydrophilic modification component is low molecular weight hyaluronic acid with a molecular weight of 100~200kDa, and the oxygen permeability modification component is trehalose or agarose.

5. The method for preparing a moisturizing protein-based contact lens according to claim 4, characterized in that, In step 2), the mixing temperature is 30~40℃, the mixing speed is 100~200rpm, and the mixing time is 20~30min; The mass ratio of the hydrophilic modified component, the oxygen-permeable modified component, and water is 2~5:1~2:15~30.

6. The method for preparing a moisturizing protein-based contact lens according to claim 5, characterized in that, In step 3), the mass ratio of the protein mixture solution, the composite modifier, and the crosslinking agent is 60~90:5~30:1~6, and the crosslinking agent is proanthocyanidins and / or tannic acid.

7. The method for preparing a moisturizing protein-based contact lens according to claim 6, characterized in that, In step 3), the mixing speed is 80~120 rpm and the mixing time is 30~60 min.

8. The method for preparing a moisturizing protein-based contact lens according to claim 1, characterized in that, In step 4), the gradient crosslinking includes a first crosslinking and a second crosslinking. The temperature of the first crosslinking is 5~10℃ and the time of the first crosslinking is 30~60min. The temperature of the second crosslinking is 20~25℃ and the time of the second crosslinking is 4~8h.

9. The method for preparing a moisturizing protein-based contact lens according to claim 8, characterized in that, In step 4), the soaking time of the buffer solution is 2-4 hours, and the buffer solution is phosphate buffer solution; The rinsing reagent is water, and the rinsing is performed 3 to 5 times, with each rinsing lasting 10 to 15 minutes. The sterilization temperature is 120~125℃, and the sterilization time is 30~60 minutes.

10. A moisturizing protein-based contact lens prepared by the method of preparing a moisturizing protein-based contact lens according to any one of claims 1 to 9.

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