3D-printed hydrogel materials, methods of making the same, and applications thereof in the preparation of smart contact lenses

Abstract

This invention belongs to the field of contact lens materials technology, specifically relating to 3D-printed hydrogel materials, their preparation methods, and their application in the fabrication of smart contact lenses. The 3D-printed hydrogel material comprises the following raw material components: hydroxyethyl methacrylate, polyethylene glycol diacrylate, 3-(trimethoxysilyl)propyl methacrylate, Pluronic F-127, poly(3,4-ethylenedioxythiophene):poly(p-phenylene sulfonate), and a photoinitiator. The 3D-printed hydrogel material provided by this invention can be directly molded into a contact lens substrate through high-precision 3D printing, thus providing a core material basis for developing next-generation comfortable, precise, and mass-producible personalized smart intraocular pressure monitoring contact lenses. This invention also provides its preparation method. Applying the hydrogel material of this invention to 3D-printed contact lenses meets the requirements for mechanical performance and comfort in contact lenses.

Description

Technical Field

[0001] This invention belongs to the field of contact lens materials technology, specifically relating to 3D printed hydrogel materials, their preparation methods, and their application in the preparation of smart contact lenses. Background Technology

[0002] Contact lenses, due to their conformal fit to the cornea, are considered an ideal wearable device platform for non-invasive and precise monitoring of physiological parameters such as intraocular pressure. Currently, smart contact lens products based on micro-strain sensing principles (such as Triggerfish) monitor corneal deformation to reflect changes in intraocular pressure by integrating rigid microelectromechanical systems (MEMS) circuitry. However, this technological approach faces significant bottlenecks: a mechanical modulus mismatch exists between the rigid MEMS device and the flexible cornea and lens substrate, which not only affects wearing comfort but may also inhibit natural corneal deformation, leading to poor consistency and accuracy of the sensing signal. Furthermore, challenges exist in lens thickness, manufacturing costs, and circuit power consumption, limiting its large-scale clinical application.

[0003] The development of flexible electronics technology offers new solutions to the aforementioned problems. By integrating flexible sensors into contact lenses, it is hoped that high-performance monitoring can be achieved while ensuring comfort. Hydrogels, as a material with high water content and excellent biocompatibility, are commonly used substrates for commercial contact lenses, and combining them with flexible electronics to construct "smart contact lenses" has become a research hotspot. For example, existing research has achieved highly sensitive wireless intraocular pressure monitoring by integrating a pyramid-shaped microstructure dielectric elastomer sensor with a pHEMA hydrogel lens through a conformal stacking assembly process, proving the feasibility of the technology. However, such methods often rely on complex multilayer integration and precision microfabrication processes, and challenges remain in manufacturing efficiency, cost control, and ensuring long-term reliable interfacial bonding between the device and the soft hydrogel matrix.

[0004] On the other hand, 3D printing technology, especially photopolymerization printing technologies such as digital light processing (DLP), provides a powerful tool for the precision manufacturing of complex three-dimensional structures, and has shown potential in the biomedical field, such as the fabrication of biomimetic corneal stromal scaffolds. Researchers have also explored the direct 3D printing of functionalized hydrogel structures on the surface of commercial contact lenses to endow them with functions such as color correction or ultraviolet sensing. Therefore, using 3D printing technology holds promise for achieving the integrated molding of sensor structures and hydrogel lens substrates, thereby simplifying the manufacturing process and enhancing structural integration and reliability.

[0005] At the materials level, photosensitive hydrogels such as gelatin methacrylamide (GelMA) have become commonly used materials for 3D bioprinting due to their good biocompatibility and photocurability. CN118718093A discloses the development of a 3D printing hydrogel with biological functions such as bidirectional regulation of hydrogen peroxide (H2O2) by combining catechol-modified gelatin methacrylate (GD) with polyethylene glycol diacrylate (PEGDA) for tissue repair. This demonstrates the possibility of endowing hydrogel materials with advanced biological functions beyond structural support through molecular design. However, current technologies lack an integrated 3D printing hydrogel material system specifically designed for smart contact lens applications that can balance excellent printing accuracy, high optical transparency, suitable mechanical properties (especially mechanical matching with the cornea), long-term wearing comfort, and stable integration of sensing functions. Most current research focuses either on the mechanical and optical properties of corneal tissue engineering scaffolds or on adding functional structures to existing lenses, failing to fundamentally design a matrix material suitable for smart manufacturing and functionally integrated contact lenses. Summary of the Invention

[0006] The technical problem this invention aims to solve is to overcome the aforementioned deficiencies of existing technologies and provide a 3D-printable hydrogel material. This material can be directly molded into a contact lens substrate through high-precision 3D printing and possesses the potential for easy integration with flexible sensing elements or inherent sensing response characteristics. This provides a core material foundation for developing next-generation, comfortable, accurate, and mass-producible smart intraocular pressure monitoring contact lenses. This invention also provides a method for its preparation. Applying this hydrogel material to 3D-printed contact lenses satisfies the requirements for mechanical performance and comfort in contact lenses.

[0007] The 3D printing hydrogel material of the present invention, based on a total weight of 100 parts of hydroxyethyl methacrylate and 3-(trimethoxysilyl)propyl methacrylate, comprises the following raw material components: 85-95 parts of hydroxyethyl methacrylate, 5-15 parts of 3-(trimethoxysilyl)propyl methacrylate, 1.5-2 parts of polyethylene glycol diacrylate, 0.3-0.6 parts of photoinitiator, 0.05-0.2 parts of Pluronic F-127, and 0.5-1.0 parts of a mixture of poly(3,4-ethylenedioxythiophene) and poly(p-styrene sulfonate).

[0008] The photoinitiator is one of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone, 2,4-diethylthioxanthrone, and ethyl phenol-formate.

[0009] The preparation method of the 3D printing hydrogel material includes the following steps: mixing hydroxyethyl methacrylate, 3-(trimethoxysilyl)propyl methacrylate, polyethylene glycol diacrylate, Pluronic F-127, poly(3,4-ethylenedioxythiophene) and poly(p-styrene sulfonate) and a photoinitiator, stirring in the dark, and then ultrasonically dispersing to obtain a uniformly dispersed 3D printing hydrogel material.

[0010] After mixing, stir in the dark using magnetic stirring at a speed of 350 r / min to 600 r / min, and then sonicate for 30 min to 70 min.

[0011] The magnetic stirring time is 60 min to 120 min.

[0012] The application of the 3D printing hydrogel material involves using it to print hydrogel smart contact lenses.

[0013] The specific steps for printing hydrogel smart contact lenses are as follows: First, use UG software to create a 3D printing model that matches the curvature of the corneal contact lens surface. Then, place the 3D printing hydrogel material into the material tank of the photopolymer 3D printer for printing.

[0014] The printing time is 120-180 minutes, followed by ultraviolet light irradiation for shaping. The ultraviolet light irradiation wavelength is 365nm-405nm, and the irradiation time is 6-8 hours.

[0015] The specific steps for creating the 3D printed model are as follows:

[0016] (1) Establish a finite element model of the cornea of ​​the contact lens wearer to obtain the geometric morphology parameters and mechanical performance parameters of the smart contact lens that match the target corneal morphology. The geometric morphology parameters of the smart contact lens include thickness, radius of curvature, base arc radius, diameter, and central area thickness. The mechanical performance parameters of the smart contact lens include elastic modulus and fracture strength.

[0017] (2) Based on the geometric parameters of the smart contact lens obtained by simulation, a 3D printing model with the same surface curvature as the smart contact lens is established.

[0018] The method for obtaining the mechanical performance parameters of smart contact lenses is as follows: the cornea is regarded as a hyperelastic, anisotropic and incompressible material, and the strain energy function HGO model proposed by Gasser, Holzapfel and Ogden is used to obtain the mechanical performance parameters of smart contact lenses. The elastic modulus of smart contact lenses is 950kPa~3500kPa, and the fracture strength is 350kPa~1200kPa.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] (1) The geometric shape and material mechanical properties of the hydrogel contact lens of the present invention are obtained by finite element modeling simulation, which fully takes into account the differences in human corneal biomechanical properties before wearing the lens and the changes in human corneal biomechanical properties after wearing the lens, so as to achieve a truly personalized design of contact lens geometry and mechanical properties.

[0021] (2) The hydrogel contact lens of the present invention achieves precise molding through photopolymerization 3D printing. By establishing a finite element model of the contact lens, the geometric morphology parameters and mechanical performance parameters of the contact lens matching the target human body are obtained. Based on the mechanical performance parameters, the type of monomer and copolymerization ratio, prepolymerization time, printing time and ultraviolet light irradiation time are determined to achieve controllable design of the geometric structure and mechanical performance of the contact lens, and realize the "customization" of the contact lens.

[0022] (3) The hydrogel contact lenses prepared by the present invention have the ability to sense changes in intraocular pressure in a timely manner and have high biocompatibility, which can meet the needs of patients to monitor intraocular pressure in real time and are comfortable to wear. Attached Figure Description

[0023] Figure 1 This is a finite element model diagram of the smart contact lens of the present invention;

[0024] Figure 2 This is a scanning electron microscope image of the inner surface of the hydrogel smart contact lens printed in Example 1;

[0025] Figure 3 A scanning electron microscope image of the outer surface of the hydrogel smart contact lens printed in Example 1;

[0026] Figure 4 This is a water contact angle test diagram of the hydrogel smart contact lens printed in Example 2;

[0027] Figure 5 The graphs show the equilibrium water content and oxygen permeability test results of the hydrogel smart contact lenses printed in Examples 2 and 3.

[0028] Figure 6 These are tensile performance test diagrams of the hydrogel smart contact lenses printed in Examples 2 and 3;

[0029] Figure 7 Figure 1 shows the resistance cycling test results of the hydrogel smart contact lens printed in Example 4 under strain conditions of 1%, 5%, and 10%.

[0030] Figure 8 The image shows the results of a thousand-cycle resistance cycling test conducted on the hydrogel smart contact lens printed in Example 4 under 10% strain conditions.

[0031] Figure 9 Image showing cell survival results from biocompatibility testing of the hydrogel contact lenses printed in Example 4;

[0032] Figure 10 The anti-inflammatory results of the biocompatibility test for the hydrogel contact lenses printed in Example 4 are shown in the figure.

[0033] Figure 11 The total infrared spectrum of the hydrogel smart contact lenses printed in Examples 1, 2, 3, and 4;

[0034] Figure 12 The total ultraviolet spectrum of the hydrogel smart contact lenses printed in Examples 1, 2, 3, and 4 is shown. Detailed Implementation

[0035] The present invention will be further described below with reference to specific embodiments. Unless otherwise specified, the raw materials used in the embodiments are all commercially available conventional raw materials; unless otherwise specified, the process methods used in the embodiments are conventional methods in the art.

[0036] The raw materials used are as follows:

[0037] Hydroxyethyl methacrylate: HEMA, 99% anhydrous;

[0038] 3-(trimethoxysilyl)propyl methacrylate: KH-570, 97%;

[0039] Polyethylene glycol diacrylate: PEGDA, 97%, average molecular weight approximately 400, containing MEHQ stabilizer;

[0040] Pluronic F-127: Biological reagent grade;

[0041] Poly(3,4-ethylenedioxythiophene) and poly(p-styrene sulfonate) mixture: PEDOT:PSS, DRY, redispersible granules;

[0042] Photoinitiator diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide: TPO, 97%, molecular weight 348.37;

[0043] Ethyl 2,4,6-trimethylbenzoylphenylphosphonate: TPO-L, 98%, molecular weight 316.3, all purchased from Aladdin Reagent Co., Ltd. (Shanghai, China).

[0044] Example 1

[0045] The specific steps of the hydrogel smart contact lens of the present invention are as follows:

[0046] (1) Preparation of 3D printing hydrogel material: 95 parts of hydroxyethyl methacrylate and 5 parts of 3-(trimethoxysilyl)propyl methacrylate were mixed, and 1.8 parts of polyethylene glycol diacrylate, 1 part of poly(3,4-ethylenedioxythiophene) and poly(p-styrene sulfonate) mixture, 0.1 parts of Pluronic F-127 and 0.6 parts of photoinitiator TPO were added in sequence. After mixing, the mixture was magnetically stirred at 350 r / min for 90 min in the dark, and then ultrasonically treated for 60 min until it was uniformly dispersed to obtain 3D printing hydrogel material.

[0047] (2) The specific steps for printing hydrogel smart contact lenses are as follows: First, a 3D printing model with the same curvature as the corneal contact lens surface is created using UG software. The designed model is as follows: Figure 1 As shown, the 3D-printed hydrogel material, with a diameter of 14.12 mm, a base arc radius of curvature of 9.97 mm, a central layer thickness of 0.22 mm, and a lens thickness of 0.2 mm, was placed in the feed tank of a photopolymer 3D printer for printing. The printing time was 150 minutes, followed by ultraviolet (UV) irradiation for shaping. The UV irradiation wavelength was 405 nm, and the irradiation time was 6 hours, resulting in a hydrogel contact lens.

[0048] The scanning electron microscope results of the hydrogel contact lenses prepared in this embodiment are as follows: Figure 2-3 As shown, Figure 2 These are scan images of the inner surface of a contact lens (two of which are attached images from two parallel tests). Figure 3 These are scan images of the outer surface of a contact lens (two of which are attached images from two parallel tests), such as... Figure 2-3 As shown, the processed contact lens has a smooth surface free of particles. All parts of the lens exhibit a consistently smooth structure, indicating that the hydrogel material can maintain morphological consistency and structural stability during the printing process. A smooth surface effectively enhances lens comfort, as a rough surface causes friction and discomfort during wear.

[0049] Example 2

[0050] The specific steps of the hydrogel smart contact lens of the present invention are as follows:

[0051] (1) Preparation of 3D printing hydrogel material: 90 parts of hydroxyethyl methacrylate and 10 parts of 3-(trimethoxysilyl)propyl methacrylate were mixed, and 1.8 parts of polyethylene glycol diacrylate, 1 part of a mixture of poly(3,4-ethylenedioxythiophene) and poly(p-styrene sulfonate), 0.1 parts of Pluronic F-127 and 0.6 parts of photoinitiator ethyl 2,4,6-trimethylbenzoylphenylphosphonate were added in sequence. After mixing, the mixture was magnetically stirred at 350 r / min for 100 min in the dark, and then ultrasonically treated for 60 min until it was uniformly dispersed to obtain 3D printing hydrogel material.

[0052] (2) The specific steps for printing hydrogel smart contact lenses are as follows: First, a 3D printing model with the same curvature as the corneal contact lens surface is created using UG software. The designed model is as follows: Figure 1 As shown, the 3D-printed hydrogel material, with a diameter of 14.12 mm, a base arc radius of curvature of 9.97 mm, a central layer thickness of 0.22 mm, and a lens thickness of 0.2 mm, was placed in the feed tank of a photopolymer 3D printer for printing. The printing time was 140 minutes, followed by ultraviolet (UV) irradiation for shaping. The UV irradiation wavelength was 405 nm, and the irradiation time was 6 hours, resulting in a hydrogel contact lens.

[0053] The water contact angle test results of the hydrogel contact lenses prepared in this embodiment are as follows: Figure 4 As shown, the water contact angle of the surface of the hydrogel contact lens is 73°, indicating that it has good hydrophilicity.

[0054] Example 3

[0055] The specific steps of the hydrogel smart contact lens of the present invention are as follows:

[0056] (1) Preparation of 3D printing hydrogel material: 90 parts of hydroxyethyl methacrylate and 10 parts of 3-(trimethoxysilyl)propyl methacrylate were mixed, and 1.8 parts of polyethylene glycol diacrylate, 0.5 parts of poly(3,4-ethylenedioxythiophene) and poly(p-styrene sulfonate) mixture, 0.1 parts of Pluronic F-127 and 0.6 parts of photoinitiator TPO were added in sequence. After mixing, the mixture was magnetically stirred at 350 r / min for 120 min in the dark, and then ultrasonically treated for 70 min until it was uniformly dispersed to obtain 3D printing hydrogel material.

[0057] (2) The specific steps for printing hydrogel smart contact lenses are as follows: First, a 3D printing model with the same curvature as the corneal contact lens surface is created using UG software. The designed model is as follows: Figure 1As shown, the 3D-printed hydrogel material, with a diameter of 14.12 mm, a base arc radius of curvature of 9.97 mm, a central layer thickness of 0.22 mm, and a lens thickness of 0.2 mm, was placed in the feed tank of a photopolymer 3D printer for printing. The printing time was 130 minutes, followed by ultraviolet (UV) irradiation for shaping. The UV irradiation wavelength was 405 nm, and the irradiation time was 6 hours, resulting in a hydrogel contact lens.

[0058] The hydrogel contact lenses prepared in Examples 2 and 3 above were tested for balanced water content (EWC) and oxygen permeability (DK). The results are as follows: Figure 5 As shown, the equilibrium water content of the contact lenses all exceeds 30%, and the oxygen permeability is also at a high level, indicating that the prepared hydrogel contact lenses have good wearing comfort.

[0059] The hydrogel contact lenses prepared in Examples 2 and 3 above were subjected to tensile performance tests, and the results are as follows: Figure 6 As shown, the stress of hydrogel contact lenses increases linearly with strain. When the strain reaches 0.17 and 0.28, the sample is destroyed, indicating that it has a high elastic modulus.

[0060] Example 4

[0061] The specific steps of the hydrogel smart contact lens of the present invention are as follows:

[0062] (1) Preparation of 3D printing hydrogel material: 85 parts of hydroxyethyl methacrylate and 15 parts of 3-(trimethoxysilyl)propyl methacrylate were mixed, and 1.8 parts of polyethylene glycol diacrylate, 1 part of poly(3,4-ethylenedioxythiophene) and poly(p-styrene sulfonate) mixture, 0.1 parts of Pluronic F-127 and 0.3 parts of photoinitiator TPO were added in sequence. After mixing, the mixture was magnetically stirred at 350 r / min for 90 min in the dark, and then ultrasonically treated for 60 min until it was uniformly dispersed to obtain 3D printing hydrogel material.

[0063] (2) The specific steps for printing hydrogel smart contact lenses are as follows: First, a 3D printing model with the same curvature as the corneal contact lens surface is created using UG software. The designed model is as follows: Figure 1 As shown, the 3D-printed hydrogel material, with a diameter of 14.12 mm, a base arc radius of curvature of 9.97 mm, a central layer thickness of 0.22 mm, and a lens thickness of 0.2 mm, was placed in the feed tank of a photopolymer 3D printer for printing. The printing time was 120 minutes, followed by ultraviolet (UV) irradiation for shaping. The UV irradiation wavelength was 405 nm, and the irradiation time was 6 hours, resulting in a hydrogel contact lens.

[0064] The conductivity of the hydrogel contact lens prepared in this embodiment was tested, and the resistance cycling test results under different strains are as follows: Figure 7 As shown, multiple and stable cyclic effects can be achieved; under 10% strain conditions, a thousand resistance cycle tests were conducted, and the results after a long period of measurement are as follows: Figure 8 As shown, the contact lens can still maintain a relatively stable resistance value, proving that the hydrogel contact lens has excellent cycle stability.

[0065] Biocompatibility testing was performed on the hydrogel contact lenses prepared in this embodiment. Cell viability after three days of culture was as follows: Figure 9 As shown (Example 4 shows "hydrogel-containing medium", 50% medium, and 100% medium), cells can still proliferate and survive normally in the medium containing hydrogel material; the anti-inflammatory test results are as follows. Figure 10 As shown, M0 macrophages differentiated into M2 macrophages. This differentiation requires the participation of anti-inflammatory factors, reflecting that the contact lens material has anti-inflammatory capabilities and demonstrating the good biocompatibility of the hydrogel contact lens.

[0066] Comparative Example 1

[0067] The difference between this comparative example and Example 4 is that the formulation of the 3D printing hydrogel material was adjusted, and the effect of the content of photoinitiator TPO on the polymerization effect of this material was investigated: 85 parts by weight of hydroxyethyl methacrylate and 15 parts by weight of 3-(trimethoxysilyl)propyl methacrylate were mixed, and then 1.8 parts by weight of polyethylene glycol diacrylate, 1 part by weight of a mixture of poly(3,4-ethylenedioxythiophene) and poly(p-phenylene sulfonate), 0.1 parts by weight of Pluronic F-127, and 0.2 parts by weight of photoinitiator TPO were added sequentially. The above substances were placed in a beaker and mixed, and then magnetically stirred at 350 r / min for 90 min in the dark, followed by ultrasonic treatment for 60 min until the dispersion was uniform, thus obtaining the 3D printing hydrogel material.

[0068] The above 3D printing hydrogel material was placed in the material tank of a photopolymer 3D printer for printing. The printing time was 150 minutes. After being irradiated with 405nm ultraviolet light for 12 hours, it still failed to form. The reason was that the photoinitiator content was too low and the number of free radicals generated was insufficient to initiate the polymerization reaction.

[0069] Comparative Example 2

[0070] The only difference between this comparative example and Example 3 is that the formulation of the 3D printing hydrogel material was adjusted, specifically the content of the poly(3,4-ethylenedioxythiophene) and poly(p-phenylene sulfonate) mixture. The effect of the change in its content on the conductivity of contact lenses was investigated: 90 parts by weight of hydroxyethyl methacrylate and 10 parts by weight of 3-(trimethoxysilyl)propyl methacrylate were mixed, followed by the addition of 1.8 parts by weight of polyethylene glycol diacrylate, 0.4 parts by weight of the poly(3,4-ethylenedioxythiophene) and poly(p-phenylene sulfonate) mixture, 0.1 parts by weight of Pluronic F-127, and 0.6 parts by weight of photoinitiator TPO. The mixture was placed in a beaker and stirred magnetically at 350 rpm for 90 min in the dark, followed by ultrasonic treatment for 60 min until uniform dispersion was obtained, thus yielding the 3D printing hydrogel material.

[0071] The specific steps for printing hydrogel smart contact lenses are as follows: First, a 3D printing model with the same curvature as the corneal contact lens surface is created using UG software. The designed model is as follows: Figure 1 As shown, the 3D-printed hydrogel material, with a diameter of 14.12 mm, a base arc radius of curvature of 9.97 mm, a central layer thickness of 0.22 mm, and a lens thickness of 0.2 mm, was placed in the feed tank of a photopolymer 3D printer for printing. The printing time was 120 minutes, followed by ultraviolet (UV) irradiation for shaping. The UV irradiation wavelength was 405 nm, and the irradiation time was 6 hours, resulting in a hydrogel contact lens.

[0072] The testing methods for the prepared hydrogel contact lenses in the above embodiments and comparative examples are as follows:

[0073] (1) Water contact angle test:

[0074] Water contact angle was tested at room temperature using a HARKE-SPCAX3 contact angle meter with a droplet size of 3.0 μL. Five measurements were taken and the average value was calculated.

[0075] (2) Equilibrium moisture content (EWC) and oxygen permeability (DK) tests:

[0076] After freeze-drying, the contact lenses were soaked in deionized water at room temperature, and measurements were taken every 2 hours until the mass no longer changed. The weight before soaking was recorded. And the weight at water absorption equilibrium is Then the equilibrium moisture content EWC = (W t -W0) / W0×100%. The DK value depends on the equilibrium water content of a water-saturated hydrogel contact lens, DK=167e 0.0397EWC The data used are the average values ​​of 5 independent tests.

[0077] (3) Elastic modulus and fracture strength test:

[0078] The tensile properties of hydrogel contact lenses were tested using a universal testing machine (INSTRON 3343). The test specimens were dumbbell-shaped, and the loading rate was 10 mm / min.

[0079] (4) Fourier transform infrared spectroscopy analysis:

[0080] First, the prepared hydrogel contact lenses were soaked in water for 2 hours, then placed in a flat polytetrafluoroethylene mold and frozen for 48 hours. Afterward, they were quickly transferred to a vacuum freeze dryer for 24 hours. The samples were then tested at room temperature using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR, Thermo Scientific Nicolet iS50), with a wavelength range of 4000-4000 cm⁻¹. -1 The scanning speed is 0.25Hz-125kHz.

[0081] (5) Ultraviolet transmittance analysis:

[0082] The optical transmission properties of contact lenses were systematically characterized using a UV-Vis spectrophotometer (Agilent Cary 60, USA), with particular attention paid to the transmission performance in the UVA (315-400 nm) band and part of the UVB (280-315 nm) band. The measurement wavelength range was set to cover the entire 400-800 nm band, a setting determined by both human visual sensitivity (400-700 nm visible light region) and UV protection requirements (<400 nm UV region). Standard phosphate-buffered saline (PBS, pH 7.4) was used as a blank control for baseline calibration before the experiment to simulate the optical behavior of the lenses in a physiological environment. A dual-beam optical system was used during the testing process to achieve measurement stability. After sterilization, the lens samples were loaded into quartz cuvettes (10 mm optical path). A three-dimensional sample holder precisely adjusted the incident light to penetrate the optical center of the lens perpendicularly. At a scanning speed of 600 nm / min, the spectral bandwidth was 1 nm. Data was acquired every 0.5 nm, and each sample had to be measured three times before the average transmittance was calculated.

[0083] (6) Biocompatibility testing methods:

[0084] Rabbit corneal epithelial cells (rCECs) were used as culture cells. Hydrogel contact lenses were immersed in culture medium for 24 hours. Cells were then cultured in culture medium without hydrogel extract (control group) and culture medium containing hydrogel extract (experimental group). Cell viability and mortality were assessed on days 1 and 3 using acridine orange (AO) green dye (10 mg / mL, 1 µL) and propidium iodide (PI) red dye (1 mg / mL, 10 µL). The stained samples were observed using a fluorescence microscope (EVOSM5000, ThermoFisher Scientific). Images of acridine orange (AO)-labeled live cells and propidium iodide (PI)-labeled dead cells were captured to study the relative cell viability in co-culture with hydrogel. A relative cell viability close to or reaching 1 indicated good biocompatibility of the hydrogel. Undifferentiated M0 macrophages (RAW 264.7) were used for in vitro inflammation assays. Macrophages were collected and seeded at a density of 50,000 cells / mL into 24-well plates, with 1 mL of cell suspension in each well. The macrophages were then co-cultured with hydrogel material for 1 day. A control group was established using M0 macrophages cultured without hydrogel material. The morphology of the macrophages was observed using an optical microscope (Olympus IX73, Japan).

[0085] (7) Conductivity Test: To enable intraocular pressure monitoring in contact lenses, the hydrogel material must possess good conductivity. First, the hydrogel was prepared into samples with a smooth surface and uniform thickness (20mm × 5mm × 1mm). Then, in a temperature and humidity controlled environment, a universal tester (TH2810B-LCR, China) was used to measure the sample using the four-point probe method. The resistance change curve over time was recorded, and the conductivity data was calculated based on the sample's geometric dimensions. During the process, it is important to maintain good contact between the probe and the sample interface and apply moderate pressure to avoid sample deformation. Multiple locations should be selected for repeated testing on each sample to improve the reliability of the results. Cyclic resistance tests under different strains and thousands of resistance cycles were also conducted to assess the cyclic stability.

[0086] Infrared analysis and ultraviolet transmittance tests were performed on the hydrogel smart contact lenses prepared in Examples 1 to 4 above. The infrared analysis results are as follows: Figure 11 As shown, the absorption peaks of the hydroxyl and ester carbonyl groups appear at 3419 cm⁻¹. -1 and 1714cm -1 Nearby, 2943cm -1 The absorption peak at that point corresponds to n-alkanes (-CH) and (-CH2). - Stretching of (-CH3) and (-CH3), 1234cm -1 The peak at 1200-1000 cm⁻¹ is assigned to the -CH₃ bending vibration, while the peak at 1200-1000 cm⁻¹ appears.-1 The bimodal pattern appearing in the interval corresponds to Si-O bonds. The test results for UV transmittance are as follows: Figure 12 As shown, the light transmittance of the contact lenses is in the range of 400-500nm, with the lowest reaching over 65% and the highest approaching 80%, proving that the hydrogel contact lenses have good light transmittance.

[0087] The test results are shown in Table 1.

[0088] Table 1 Test Results

[0089]

[0090] As can be seen from Table 1, the wearing comfort and biocompatibility of the hydrogel contact lens are very good. In Comparative Example 2, after reducing the total amount of the added conductive materials PEDOT and PSS, its resistance cycle stability deteriorated, its conductivity decreased, and its fracture strength decreased. This may be because the reduction in their content leads to a decrease in the amount of conductive material inside the contact lens, and the ability of the hydrogel network structure formed by polymerizing with other materials to resist deformation is reduced.

Claims

1. A 3D printing hydrogel material, characterized in that, Based on a total weight of 100 parts of hydroxyethyl methacrylate and 3-(trimethoxysilyl)propyl methacrylate, the raw material components include the following: 85-95 parts of hydroxyethyl methacrylate, 5-15 parts of 3-(trimethoxysilyl)propyl methacrylate, 1.5-2 parts of polyethylene glycol diacrylate, 0.3-0.6 parts of photoinitiator, 0.05-0.2 parts of Pluronic F-127, and 0.5-1.0 parts of a mixture of poly(3,4-ethylenedioxythiophene) and poly(p-styrene sulfonate); The photoinitiator is one of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone, and 2,4-diethylthioxanthrone.

2. A method for preparing the 3D printing hydrogel material according to claim 1, characterized in that: The process includes the following steps: mixing hydroxyethyl methacrylate, 3-(trimethoxysilyl)propyl methacrylate, polyethylene glycol diacrylate, Pluronic F-127, poly(3,4-ethylenedioxythiophene) and poly(p-styrene sulfonate) and a photoinitiator, stirring in the dark, and then ultrasonically dispersing to obtain a uniformly dispersed 3D printing hydrogel material.

3. The method for preparing 3D printed hydrogel material according to claim 2, characterized in that: After mixing, stir in the dark using magnetic stirring at a speed of 350 r / min to 600 r / min, and then sonicate for 30 min to 70 min.

4. The method for preparing 3D printed hydrogel material according to claim 3, characterized in that: The magnetic stirring time is 60 min to 120 min.

5. The application of the 3D printing hydrogel material as described in claim 1 in the fabrication of smart contact lenses, characterized in that, The specific steps for printing hydrogel smart contact lenses are as follows: First, use UG software to create a 3D printing model that matches the curvature of the corneal contact lens surface. Then, place the 3D printing hydrogel material into the material tank of the photopolymer 3D printer for printing.

6. The application of the 3D printing hydrogel material according to claim 5, characterized in that: The printing time is 120-180 minutes, followed by ultraviolet light irradiation for shaping. The ultraviolet light irradiation wavelength is 365nm-405nm, and the irradiation time is 6-8 hours.

7. The application of the 3D printing hydrogel material according to claim 5 or 6, characterized in that, The specific steps for creating the 3D printed model are as follows: (1) Establish a finite element model of the cornea of ​​the contact lens wearer to obtain the geometric morphology parameters and mechanical performance parameters of the smart contact lens that match the target corneal morphology. The geometric morphology parameters of the smart contact lens include thickness, radius of curvature, base arc radius, diameter, and central area thickness. The mechanical performance parameters of the smart contact lens include elastic modulus and fracture strength. (2) Based on the geometric parameters of the smart contact lens obtained by simulation, a 3D printing model with the same surface curvature as the smart contact lens is established.

8. The application of the 3D printing hydrogel material according to claim 7, characterized in that: The method for obtaining the mechanical performance parameters of smart contact lenses is as follows: the cornea is regarded as a hyperelastic, anisotropic and incompressible material, and the strain energy function HGO model proposed by Gasser, Holzapfel and Ogden is used to obtain the mechanical performance parameters of smart contact lenses. The elastic modulus of smart contact lenses is 950kPa~3500kPa, and the fracture strength is 350kPa~1200kPa.

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