PVA hydrogel-based artificial cornea and preparation method therefor

Abstract

A PVA hydrogel-based artificial cornea and a preparation method therefor. The artificial cornea comprises an optical center part and a skirt support, wherein the optical center part comprises a composite PVA hydrogel based on PVA and amino acid / caffeic acid modified chitosan; and the skirt support comprises PVA, amino acid / caffeic acid modified chitosan, nanophosphate, and polyethylene glycol hydroxy acid. The prepared artificial cornea has sufficient optical properties, excellent mechanical properties, good biocompatibility and infection resistance, reduced occurrence of post-implantation complications, and high safety.

Description

An artificial cornea based on PVA hydrogel and a preparation method thereof

[0001] The present application claims priority to the Chinese patent application No. 202411303409.0, filed on September 19, 2024, and entitled "An artificial cornea based on PVA hydrogel and a preparation method thereof", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of implant materials in medical devices and artificial organ technology, in particular to an artificial cornea based on PVA hydrogel and a preparation method thereof. BACKGROUND

[0003] The cornea is one of the tissues that make up the eyeball, and corneal diseases are common in ophthalmology. The common treatment method for corneal diseases is corneal transplantation. Traditional corneal transplantation is generally to transplant the cornea of another person, but the cornea resource is scarce, and the biological tissue of another person transplanted into the patient's body in corneal transplantation may cause rejection or infection. Artificial cornea as a cornea replacement material can solve the problem of lack of cornea donors to a great extent.

[0004] In early artificial corneas, almost the entire part of the artificial cornea is usually formed by a dense transparent inorganic material such as glass and a transparent resin such as polymethyl acrylate. However, such artificial corneas have low adhesion to biological tissues, and exert mechanical stress on the eyeball, which can easily cause deviation or infection of the artificial cornea, and it is very difficult to use the artificial cornea for a long time. Based on the above problems, people have developed artificial corneas formed by soft materials or fibrous materials with high biocompatibility. However, current artificial corneal transplantation still has many problems, such as the poor mechanical properties of hydrogels, which are easily torn during surgical suturing, even if the artificial cornea is successfully implanted, inflammation will occur due to the poor combination of eye tissue and artificial cornea, and the swelling resistance needs to be improved.

[0005] Polyvinyl alcohol has high compatibility with human tissues, no toxicity, no side effects, no degradation, stable chemical properties, excellent mechanical properties, and high water content, and is a very potential artificial cornea replacement material. However, its mechanical properties still have some differences with human cartilage, and it is difficult to obtain sufficient optical properties (such as high transparency, appropriate refractive index, or low scattering properties).

[0006] Therefore, there is an urgent need for an artificial cornea that has good biocompatibility, good mechanical properties, optical properties, and other properties.

[0007] SUMMARY

[0008] The present application aims at the deficiencies of the prior art, and provides a PVA hydrogel-based artificial cornea and a preparation method thereof.

[0009] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0010] In one aspect, the PVA hydrogel-based artificial cornea comprises an optical center part and a skirt support.

[0011] The optical center part comprises a composite PVA hydrogel based on PVA and amino acid / coffee acid modified chitosan.

[0012] The skirt support comprises PVA, amino acid / coffee acid modified chitosan, nano-phosphate, and polyethylene glycol hydroxy acid.

[0013] Further, the mass ratio of PVA to amino acid / coffee acid modified chitosan in the optical center part is 100:(8-15), and more preferably 100:12.

[0014] Further, the amino acid / coffee acid modified chitosan is prepared by modifying chitosan with amino acid and coffee acid; the mass ratio of chitosan, amino acid, and coffee acid is 10:(0.5-1):(0.2-0.3); preferably, the mass ratio of chitosan, amino acid, and coffee acid is 10:0.8:0.26.

[0015] Preferably, the amino acid is selected from any one or a combination of several of asparagine, glutamine, lysine, and tyrosine.

[0016] The above-mentioned amino acid / coffee acid modified chitosan is prepared by the following method:

[0017] (1) Dissolve amino acid, EDC (1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride), and NHS (N-hydroxysuccinimide) in double distilled water at room temperature to obtain an activated amino acid solution;

[0018] (2) Dissolve chitosan in acid to obtain a chitosan solution;

[0019] (3) Dissolve coffee acid and EDC in ethanol water to obtain a coffee acid solution;

[0020] (4) Mix the activated amino acid solution, the chitosan solution, and the coffee acid solution in steps (1) to (3), protect the reaction under nitrogen, adjust the pH to weak alkalinity after the reaction is completed, wash out the product by dialysis, and freeze-dry to obtain the amino acid modified chitosan.

[0021] Preferably, in step (1), the mass ratio of the amino acid, EDC, and NHS is 1:(2-3):(0.5-1).

[0022] Preferably, in step (2), the acid is any one of dilute hydrochloric acid, oleic acid, dilute nitric acid, and acetic acid with pH=5-5.5.

[0023] Preferably, in step (3), the mass ratio of the caffeic acid and EDC is 1:(1.5-3); and the volume ratio of ethanol to water in the ethanol aqueous solution is (20-60):(40-80).

[0024] Preferably, in step (4), the reaction time is 12-24 h, and the reaction temperature is 40-50°C.

[0025] Further, in the skirt support, the mass ratio of the PVA, the amino acid / caffeic acid modified chitosan, the polyethylene glycol hydroxy acid, and the nano-phosphate is 100:(5-10):(7-12):(5-10); and preferably, the mass ratio is 100:8:10:7.

[0026] Further, the skirt support further comprises cyclodextrin modified carbon nanotubes, and the addition amount of the cyclodextrin modified carbon nanotubes is 5-7.5% of the mass of the PVA; the cyclodextrin modified carbon nanotubes are prepared by the following method:

[0027] (1) The carbon nanotubes are placed in an acid for ultrasonic treatment to obtain carboxylated carbon nanotubes;

[0028] (2) The carboxylated carbon nanotubes and cyclodextrin are added to water, EDC and NHS are added, and the mixture is reacted overnight, filtered, and washed with water until neutral to obtain the cyclodextrin modified carbon nanotubes.

[0029] Preferably, in step (1), the acid is concentrated sulfuric acid and / or concentrated nitric acid.

[0030] Preferably, in step (1), the cyclodextrin is γ-cyclodextrin.

[0031] Preferably, in step (2), the mass ratio of the carboxylated carbon nanotubes to the cyclodextrin is 1:(0.25-0.32).

[0032] In another aspect, the preparation method of the PVA hydrogel-based artificial cornea described above comprises the following steps:

[0033] S1, PVA, amino acid / caffeic acid modified chitosan, polyethylene glycol hydroxy acid, and nano-phosphate are dispersed in water to form a spinning solution, and a non-woven fabric with middle through holes is prepared by electrospinning as a skirt support;

[0034] S2, mixing PVA, amino acid / caffeic acid modified chitosan, dimethyl sulfoxide and water to obtain a composite PVA hydrogel precursor solution;

[0035] S3, immersing the non-woven fabric in the composite PVA hydrogel precursor solution, and performing freeze-thaw treatment for 4-5 times to fix the PVA composite hydrogel on the surface of the non-woven fabric to form an optical center part, and then washing with water to remove the solvent to obtain the product.

[0036] Further, in step S1, the mass ratio of the total mass of PVA, amino acid / caffeic acid modified chitosan and nano-phosphate to the mass of water is (25-35):(65-75).

[0037] Further, in step S2, the mass ratio of the total mass of PVA and amino acid / caffeic acid modified chitosan to dimethyl sulfoxide and water is 1:(5-6):(1-2).

[0038] Further, in step S3, the freeze-thaw treatment process is as follows: freezing at-20 to-30℃ for 14-16h, and then placing at room temperature for 3.5-5h, repeating the process for 4-5 times to complete the freeze-thaw treatment.

[0039] Further, in step S1, before immersing the non-woven fabric in the composite PVA hydrogel precursor solution, the composite PVA hydrogel precursor solution is subjected to microwave treatment and infrared treatment in sequence; the microwave treatment is performed at a power of 140-180W for 30-50min; and the infrared treatment is performed at a wavelength of 780-850nm for 20-30min. The applicant found that, the prior infrared treatment and then microwave treatment of the composite PVA hydrogel precursor solution can help to obtain uniform PVA hydrogel, further improve the mechanical properties, reduce the defect that the PVA hydrogel is easily torn due to poor mechanical strength during surgical suturing, and improve the success rate of artificial cornea implantation.

[0040] Compared with the prior art, the present application has the following beneficial effects:

[0041] 1. The present application provides an artificial cornea based on PVA hydrogel and a preparation method thereof. The artificial cornea has good biocompatibility, high water content, good optical properties, excellent mechanical properties, and the advantages of sterilization and anti-inflammation, and can reduce the occurrence of post-implantation complications.

[0042] 2、The application provides an artificial cornea based on PVA hydrogel, which is prepared by adding amino acid / coffee acid modified chitosan into the optical center part and the skirt support material, the introduction of amino acid into the chitosan helps to enhance the biocompatibility and antibacterial property of the chitosan, and makes up for the defect of poor mechanical property of the chitosan after water absorption; the introduction of coffee acid into the chitosan further increases the antibacterial property and anti-inflammatory property of the chitosan and reduces the anti-infective property; in addition, the applicant has found that the simultaneous introduction of amino acid and coffee acid into the chitosan can greatly improve the antibacterial property and long-acting antibacterial property, and also enables the modified chitosan to form a more uniform three-dimensional network cross-linking structure with the PVA hydrogel, so that the mechanical property is greatly improved, the defect of poor mechanical property of the existing PVA hydrogel and the easy tearing during surgical suture is made up, and the safety is improved; on the other hand, the water content and the light transmittance of the PVA hydrogel are also improved, so that the artificial cornea has sufficient optical transparency.

[0043] 3、The artificial cornea based on PVA hydrogel of the application adds cyclodextrin modified carbon nanotubes into the skirt support, compared with unmodified carbon nanotubes, the compatibility of the modified carbon nanotubes with PVA and other materials is better, the mechanical strength and toughness of the skirt support can be improved, and the implant safety is improved; in addition, the addition of cyclodextrin modified carbon nanotubes and polyethylene glycol hydroxy acid has a certain synergistic effect, which not only greatly improves the mechanical property, but also helps to improve the hydrophilicity and the water content. DETAILED DESCRIPTION

[0044] The following non-limiting examples can enable those skilled in the art to have a more comprehensive understanding of the application, but do not limit the application in any way. The following content is only an exemplary description of the scope of the application claimed by the application, and those skilled in the art can make various changes and modifications to the application disclosed, which should also belong to the scope of the application claimed.

[0045] The application will be further described in the following specific examples. The various chemical reagents used in the examples of the application are obtained through conventional commercial channels unless otherwise specified.

[0046] Example 1

[0047] An artificial cornea based on PVA hydrogel, comprising an optical center part and a skirt support;

[0048] The optical center part comprises a composite PVA hydrogel based on PVA and amino acid / coffee acid modified chitosan; the mass ratio of PVA to amino acid / coffee acid modified chitosan is 100:8;

[0049] The skirt support comprises PVA, amino acid / coffee acid modified chitosan, polyethylene glycol hydroxy acid and nano-phosphate with a mass ratio of 100:5:7:5.

[0050] wherein the amino acid / caffeic acid modified chitosan is prepared by the following method:

[0051] (1) 0.5 parts by weight of amino acid, 1 part by weight of EDC, 0.25 parts by weight of NHS are dissolved in 50 parts by weight of double distilled water to obtain an activated amino acid solution;

[0052] (2) 10 parts by weight of chitosan is dissolved in 20 parts by weight of hydrochloric acid with pH = 5.5 to obtain a chitosan solution;

[0053] (3) 0.2 parts by weight of caffeic acid, 0.35 parts by weight of EDC are dissolved in 50 parts by weight of ethanol water (volume ratio 6:4) to obtain a caffeic acid solution;

[0054] (4) The activated amino acid solution, chitosan solution and caffeic acid solution in steps (1) to (3) are mixed, and the reaction is carried out under nitrogen protection at 40°C for 24h. After the reaction is completed, the pH is adjusted to 7.5, the product is washed out by dialysis, and then freeze-drying is performed to obtain the amino acid modified chitosan.

[0055] The embodiment also provides a preparation method of a PVA hydrogel-based artificial cornea, including the following steps:

[0056] S1, 25 parts by weight of PVA, amino acid / caffeic acid modified chitosan, polyethylene glycol hydroxy acid and nano-phosphate are dispersed in 75 parts of water to form a spinning solution, and a non-woven fabric with middle through holes is prepared by electrospinning as a skirt support;

[0057] S2, 10 parts by weight of PVA and amino acid / caffeic acid modified chitosan are uniformly mixed with 50 parts by weight of dimethyl sulfoxide and 20 parts by weight of water to obtain a composite PVA hydrogel precursor solution;

[0058] S3, the non-woven fabric is immersed in the composite PVA hydrogel precursor solution, frozen at -200°C for 16h, and then placed at room temperature for 3.5h. The process is repeated 4 times to complete the freeze-thaw treatment.

[0059] Example 2

[0060] A PVA hydrogel-based artificial cornea includes an optical central part and a skirt support;

[0061] The optical central part comprises a composite PVA hydrogel based on PVA and amino acid / caffeic acid modified chitosan; the mass ratio of PVA to amino acid / caffeic acid modified chitosan is 100:12;

[0062] The skirt support comprises PVA, amino acid / caffeic acid modified chitosan, polyethylene glycol hydroxy acid and nano-phosphate with a mass ratio of 100:8:10:7.

[0063] The amino acid / caffeic acid modified chitosan is prepared by the following method:

[0064] (1) 0.8 parts by weight of amino acid, 0.8 parts by weight of EDC, and 0.8 parts by weight of NHS are dissolved in 50 parts by weight of double distilled water to obtain an activated amino acid solution;

[0065] (2) 10 parts by weight of chitosan is dissolved in 20 parts by weight of hydrochloric acid with pH = 5.5 to obtain a chitosan solution;

[0066] (3) 0.26 parts by weight of caffeic acid and 0.78 parts by weight of EDC are dissolved in 50 parts by weight of ethanol water (volume ratio 6:4) to obtain a caffeic acid solution;

[0067] (4) The activated amino acid solution, the chitosan solution, and the caffeic acid solution in steps (1) to (3) are mixed, and the reaction is carried out under nitrogen protection at 50°C for 12h. After the reaction is completed, the pH is adjusted to 7.5, the product is washed out by dialysis, and freeze-drying is performed to obtain the amino acid modified chitosan.

[0068] The embodiment also provides a preparation method of a PVA hydrogel-based artificial cornea, including the following steps:

[0069] S1, 35 parts by weight of PVA, amino acid / caffeic acid modified chitosan, polyethylene glycol hydroxy acid, and nano-phosphate are dispersed in 65 parts of water to form a spinning solution, and a non-woven fabric with a middle through hole is prepared by electrospinning as a skirt support;

[0070] S2, 10 parts by weight of PVA and amino acid / caffeic acid modified chitosan are uniformly mixed with 60 parts by weight of dimethyl sulfoxide and 10 parts by weight of water to obtain a composite PVA hydrogel precursor solution;

[0071] S3, the non-woven fabric is immersed in the composite PVA hydrogel precursor solution, frozen at -200°C for 16h, and then placed at room temperature for 3.5h. The process is repeated 5 times to complete the freeze-thaw treatment.

[0072] Example 3

[0073] A PVA hydrogel-based artificial cornea includes an optical central part and a skirt support;

[0074] The optical central part contains a composite PVA hydrogel based on PVA and amino acid / caffeic acid modified chitosan; the mass ratio of PVA to amino acid / caffeic acid modified chitosan is 100:15;

[0075] The skirt support contains PVA, amino acid / caffeic acid modified chitosan, polyethylene glycol hydroxy acid, and nano-phosphate with a mass ratio of 100:10:12:10.

[0076] The amino acid / caffeic acid modified chitosan is prepared by the following method:

[0077] (1) 1 part by weight of amino acid, 1 part by weight of EDC, 1 part by weight of NHS are dissolved in 50 parts by weight of double distilled water to obtain an activated amino acid solution;

[0078] (2) 10 parts by weight of chitosan are dissolved in 20 parts by weight of hydrochloric acid with pH = 5.5 to obtain a chitosan solution;

[0079] (3) 0.3 parts by weight of caffeic acid, 0.9 parts by weight of EDC are dissolved in 50 parts by weight of ethanol water (volume ratio 6:4) to obtain a caffeic acid solution;

[0080] (4) The activated amino acid solution, the chitosan solution and the caffeic acid solution in steps (1) to (3) are mixed, and the reaction is carried out under nitrogen protection at 50°C for 12h. After the reaction is completed, the pH is adjusted to 7.5, the product is washed out by dialysis, and then freeze-drying is performed to obtain the amino acid modified chitosan.

[0081] The embodiment also provides a preparation method of a PVA hydrogel-based artificial cornea, including the following steps:

[0082] S1, 35 parts by weight of PVA, amino acid / caffeic acid modified chitosan, polyethylene glycol hydroxy acid and nano-phosphate are dispersed in 65 parts of water to form a spinning solution, and a non-woven fabric with middle through holes is prepared by electrospinning as a skirt support;

[0083] S2, 10 parts by weight of PVA and amino acid / caffeic acid modified chitosan are uniformly mixed with 60 parts by weight of dimethyl sulfoxide and 10 parts by weight of water to obtain a composite PVA hydrogel precursor solution;

[0084] S3, the non-woven fabric is immersed in the composite PVA hydrogel precursor solution, frozen at-200°C for 16h, and then placed at room temperature for 3.5h. The process is repeated 5 times to complete the freeze-thaw treatment.

[0085] Example 4

[0086] The difference from example 2 is that in this embodiment, the mass ratio of chitosan, amino acid and caffeic acid in the preparation process of the amino acid / caffeic acid modified chitosan is 10:0.3:0.1.

[0087] Example 5

[0088] The difference from example 2 is that in this embodiment, the mass ratio of chitosan, amino acid and caffeic acid in the preparation process of the amino acid / caffeic acid modified chitosan is 10:1.2:0.5.

[0089] Example 6

[0090] The difference from Example 2 is that in this example, the mass ratio of PVA to amino acid / caffeic acid modified chitosan in the optical center part is 100:5.

[0091] Example 7

[0092] The difference from Example 2 is that in this example, the mass ratio of PVA to amino acid / caffeic acid modified chitosan in the optical center part is 100:18.

[0093] Example 8

[0094] The difference from Example 2 is that in this example, 5% of PVA in the skirt support is replaced by cyclodextrin modified carbon nanotubes; wherein the cyclodextrin modified carbon nanotubes are prepared by the following method:

[0095] (1) Put 1 part by weight of carbon nanotubes into 50 parts by weight of concentrated nitric acid, ultrasonic treatment for 20 min, water washing to neutral, drying to get carboxylated carbon nanotubes;

[0096] (2) Add 1 part by weight of carboxylated carbon nanotubes and 0.25 parts by weight of cyclodextrin to 100 parts by weight of water, add 1 part by weight of EDC and 1 part by weight of NHS, react overnight under ice bath condition, suction filtration, water washing to neutral to get cyclodextrin modified carbon nanotubes.

[0097] Example 9

[0098] The difference from Example 8 is that in this example, an equal amount of carboxylated carbon nanotubes is used instead of cyclodextrin modified carbon nanotubes.

[0099] Example 10

[0100] The difference from Example 8 is that in this example, an equal amount of unmodified carbon nanotubes is used instead of cyclodextrin modified carbon nanotubes.

[0101] Example 11

[0102] The difference from Example 2 is that in this example, the step S2 of preparing the PVA hydrogel-based artificial cornea includes: mixing 10 parts by weight of PVA and amino acid / caffeic acid modified chitosan with 60 parts by weight of dimethyl sulfoxide and 10 parts by weight of water, microwave treatment under the condition of 180W for 30min, and then infrared treatment under the wavelength of 850nm for 20min to get the composite PVA hydrogel precursor solution.

[0103] Example 12

[0104] The difference between the example 2 and the present example is that, in the present example, the step S2 of preparing the PVA-based hydrogel artificial cornea comprises: mixing 10 parts by weight of PVA and amino acid / caffeic acid modified chitosan together, 60 parts by weight of dimethyl sulfoxide and 10 parts by weight of water, and treating the mixture with infrared light at a wavelength of 850 nm for 20 min to obtain a composite PVA hydrogel precursor solution.

[0105] Comparative Example 1

[0106] The difference between the example 2 and the present example is that, in the present example, the step S2 of preparing the PVA-based hydrogel artificial cornea comprises: mixing 10 parts by weight of PVA and amino acid / caffeic acid modified chitosan together, 60 parts by weight of dimethyl sulfoxide and 10 parts by weight of water, and treating the mixture with infrared light at a wavelength of 850 nm for 20 min to obtain a composite PVA hydrogel precursor solution.

[0107] (1) 0.8 parts by weight of amino acid, 0.8 parts by weight of EDC and 0.8 parts by weight of NHS were dissolved in 50 parts by weight of double distilled water to obtain an activated amino acid solution;

[0108] (2) 10 parts by weight of chitosan was dissolved in 20 parts by weight of hydrochloric acid with pH = 5.5 to obtain a chitosan solution;

[0109] (3) The activated amino acid solution and the chitosan solution were mixed, and the mixture was protected by nitrogen and reacted at 50°C for 12 h. After the reaction was completed, the pH was adjusted to 7.5, the product was washed out and dialyzed, and then freeze-dried to obtain the amino acid modified chitosan.

[0110] Comparative Example 2

[0111] The difference between the example 2 and the present example is that, in the present example, the step S2 of preparing the PVA-based hydrogel artificial cornea comprises: mixing 10 parts by weight of PVA and amino acid / caffeic acid modified chitosan together, 60 parts by weight of dimethyl sulfoxide and 10 parts by weight of water, and treating the mixture with infrared light at a wavelength of 850 nm for 20 min to obtain a composite PVA hydrogel precursor solution.

[0112] (1) 10 parts by weight of chitosan was dissolved in 20 parts by weight of hydrochloric acid with pH = 5.5 to obtain a chitosan solution;

[0113] (2) 0.26 parts by weight of caffeic acid and 0.78 parts by weight of EDC were dissolved in 50 parts by weight of ethanol water (volume ratio 6:4) to obtain a caffeic acid solution;

[0114] (3) The chitosan solution and the caffeic acid solution were mixed, and the mixture was protected by nitrogen and reacted at 50°C for 12 h. After the reaction was completed, the pH was adjusted to 7.5, the product was washed out and dialyzed, and then freeze-dried to obtain the amino acid modified chitosan.

[0115] Comparative Example 3

[0116] The difference between the example 2 and the present example is that, in the present example, the step S2 of preparing the PVA-based hydrogel artificial cornea comprises: mixing 10 parts by weight of PVA and amino acid / caffeic acid modified chitosan together, 60 parts by weight of dimethyl sulfoxide and 10 parts by weight of water, and treating the mixture with infrared light at a wavelength of 850 nm for 20 min to obtain a composite PVA hydrogel precursor solution.

[0117] Comparative Example 4

[0118] The difference from Example 2 is that in this comparative example, no amino acid / caffeic acid modified chitosan is added in the keratoprosthesis.

[0119] Comparative Example 5

[0120] The difference from Example 8 is that in this comparative example, no polyethylene glycol hydroxy acid is added in the skirt support.

[0121] Test Example 1

[0122] The keratoprosthesis obtained in the above examples and comparative examples is tested for light transmittance, water absorption, mechanical properties, and antibacterial properties. The specific testing methods are as follows:

[0123] 1. Light transmittance: Take the sample at the optical center, and test the light transmittance in the wavelength range of 400-800 nm by ultraviolet spectrophotometry.

[0124] 2. Water content test: Take an appropriate amount of swelled sample, wipe off the surface moisture, weigh the film as W1, completely dry it and weigh as W2, and calculate the water content R = (W1-W2) / W1 x 100%.

[0125] 3. Mechanical properties: The tensile strength and elongation at break are tested according to GB / T1040-Plastics Determination of tensile properties, and the sample size is 10mm x 40mm, which is tested at room temperature with a tensile rate of 30mm / min.

[0126] 4. Corneal suture: Two 5-0 sutures are inserted into the edges of the decellularized keratoprosthesis at both ends, and are fixed on the clamps at both ends of the mechanical testing machine. The two ends are stretched at a speed of 50mm / min until the sutures tear the decellularized keratoprosthesis. The maximum tensile force at which the sutures tear the decellularized keratoprosthesis is recorded as the suture force.

[0127] 5. Antibacterial properties

[0128] The test is performed by the inhibition zone method, and the test strains are Staphylococcus aureus, Escherichia coli, and Bacillus subtilis. The antibacterial properties of the sample after being placed for 8 months are also tested.

[0129] The test results are shown in Tables 1 and 2 below.

[0130] Table 1

[0131] The results show that the artificial cornea prepared by the method of the application has a light transmittance of 90% or more at 700 nm, good optical properties, a water content of 80% or more, a light transmittance and a water content similar to those of a normal human cornea, a tensile strength of about 3 MPa, an elongation at break of 400% or more, excellent mechanical properties, a maximum suture load of 1 MPa or more, and the ability to withstand the cutting force of suture threads, thereby improving the success rate and safety of implantation.

[0132] Table 2

[0133] The results show that the artificial cornea prepared by the method of the application has an antibacterial ring diameter of 30 mm or more against Staphylococcus aureus, Escherichia coli, and Bacillus subtilis, has excellent antibacterial properties, and has an antibacterial ring diameter of more than 20 mm after 14 days, with long-lasting antibacterial properties. Compared with the antibacterial properties of Examples 2, 4-8, and Comparative Examples 1-4 at 14 days, the antibacterial properties of the amino acid / coffee acid modified chitosan are significantly reduced. It can be seen that the addition of amino acid / coffee acid modified chitosan not only helps to improve the antibacterial properties of the artificial cornea, but also endows it with long-lasting antibacterial properties.

[0134] Test Example 2

[0135] Cytotoxicity test

[0136] The in vitro cytotoxicity test was performed by MTT colorimetric method, and the specific steps were as follows:

[0137] (1) Sample extraction solution preparation

[0138] Under sterile operation, 90 cm 2 of the sample was added to 15.00 mL of extraction medium (10% fetal bovine serum MEM (1xMEM)) at a ratio of 6 cm 2 / mL, and the extraction stock solution was obtained after 24 h of extraction at 37°C. Before use, it was filtered with a 0.22 um sterile filter membrane.

[0139] Positive control group: 10% fetal bovine serum MEM (1xMEM) containing 5% DMSO.

[0140] Blank control group: 10% fetal bovine serum MEM (1xMEM).

[0141] (2) Set up blank group, negative control group, positive control group, sample group, each group has 6 parallel holes (96 well cell culture plate), the density is 1×10 4The cell suspension of 1.5x105cells / mL was inoculated into each group of parallel holes, 100 mL of cell suspension was added to each hole, and the cells were cultured in a 37°C incubator containing 5% CO2 for 24 h. After the culture ended, the original culture solution was discarded, fresh cell culture solution was added to the blank control group, the positive control solution was added to the positive control group, and the sample extract was added to the sample group, 100 mL per hole. Then the culture was continued for 72 h. After the culture ended, the morphology of the cultured cells was observed under a microscope. MTT with a density of 5 g was added to each group of parallel holes, 20 mL per hole. After 4 h of continuous culture, the culture solution was discarded, 150 L of DMSO was added, the DMSO solution containing the cells was placed on a shaker for 10 min, and the absorbance at 570 nm and 630 nm was measured by an enzyme-labeled instrument. The proliferation rate RGR was calculated as A / A0x 100%. Wherein, A is the absorbance of the sample or the positive control group; A0is the absorbance of the blank control group.

[0142] (3) The cytotoxicity reaction grading evaluation standard is shown in Table 3 below.

[0143] Table 3

[0144] (4) The test results are shown in Table 4 below.

[0145] Table 4

[0146] The results show that the artificial cornea of Comparative Example 4 does not add amino acid / caffeic acid modified chitosan, and compared with Comparative Example 4, the artificial corneas of Comparative Examples 1-3 have a certain inhibitory effect on cell proliferation, while the artificial corneas prepared by the method of the present application have a significant promoting effect on cell proliferation, and the cell proliferation rate is more than 90%, i.e. the artificial cornea provided by the present application has good biocompatibility and can ensure the normal growth of cells.

[0147] In addition, after the artificial cornea extract provided by the present application was injected into mice through acute systemic toxicity test, the mice were normal and no obvious symptoms appeared, and there was no acute systemic toxicity reaction.

[0148] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and use the application. Those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described herein to other embodiments without creative labor. Therefore, the present application is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present application without departing from the scope of the present application should be within the scope of protection of the present application.

Claims

1. A PVA hydrogel-based keratoprosthesis, comprising an optical central part and a skirt support, wherein, the optical central part comprises a composite PVA hydrogel based on PVA and amino acid / caffeic acid modified chitosan; the skirt support comprises PVA, amino acid / caffeic acid modified chitosan, nano-phosphate, polyethylene glycol hydroxy acid.

2. The PVA-based hydrogel-based keratoprosthesis of claim 1, wherein, The mass ratio of PVA to amino acid / caffeic acid modified chitosan in the optical central part is 100:(8-15).

3. The PVA-based hydrogel-based keratoprosthesis of claim 1, wherein, The amino acid / caffeic acid modified chitosan is prepared by modifying chitosan with amino acid and caffeic acid; The mass ratio of chitosan, amino acid and caffeic acid is 10:(0.5-1):(0.2-0.3).

4. The PVA-based hydrogel-based keratoprosthesis of claim 1, wherein, The amino acid is selected from any one or a combination of asparagine, glutamine, lysine and tyrosine.

5. The PVA-based hydrogel-based keratoprosthesis of claim 1, wherein, In the skirt support, the mass ratio of PVA, amino acid / caffeic acid modified chitosan, polyethylene glycol hydroxy acid and nano-phosphate is 100:(5-10):(7-12):(5-10).

6. The PVA-based hydrogel keratoprosthesis of any of claims 1-5, wherein, The skirt support further comprises cyclodextrin modified carbon nanotubes; the addition amount of the cyclodextrin modified carbon nanotubes is 5-7.5% of the mass of PVA.

7. The PVA-based hydrogel-based keratoprosthesis of claim 6, wherein, The cyclodextrin modified carbon nanotubes are prepared by the following method: (1) Put the carbon nanotubes into acid and ultrasonically treat to obtain carboxylated carbon nanotubes; (2) Add the carboxylated carbon nanotubes and cyclodextrin to water, add EDC and NHS, react overnight, suction filter and wash with water until neutral to obtain cyclodextrin modified carbon nanotubes.

8. The PVA-based hydrogel-based keratoprosthesis of claim 7, wherein, The mass ratio of the carboxylated carbon nanotubes to cyclodextrin is 1:(0.25-0.32).

9. A method for the production of a PVA-based hydrogel keratoprosthesis according to any one of claims 1-8, wherein, The method comprises the following steps: S1, disperse PVA, amino acid / caffeic acid modified chitosan, polyethylene glycol hydroxy acid and nano-phosphate in water to form a spinning solution, and prepare a non-woven fabric with intermediate through holes as the skirt support by electrospinning; S2, mix PVA, amino acid / caffeic acid modified chitosan, dimethyl sulfoxide and water uniformly to obtain a composite PVA hydrogel precursor solution; S3, immerse the non-woven fabric in the composite PVA hydrogel precursor solution, freeze-thaw for 4-5 times, fix the PVA composite hydrogel on the surface of the non-woven fabric to form the optical central part, and then wash with water to remove the solvent. The freeze-thaw process is as follows: freeze at -20 to -30℃ for 14-16h, then place at room temperature for 3.5-5h, repeat the process for 4-5 times, and then complete the freeze-thaw process.

10. The method of claim 9, wherein the PVA-based hydrogel artificial cornea is prepared by the steps of: ​

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