Sensitivity-adjustable contact lens type intraocular pressure monitoring equipment and preparation method thereof

Abstract

According to the contact lens type intraocular pressure monitoring equipment capable of regulating and controlling the sensitivity and the preparation method of the contact lens type intraocular pressure monitoring equipment, a sensing unit is made of a composite two-dimensional conductive material prepared from Ti3T2Cx MXene and carboxylated multi-walled carbon nanotubes in different proportions, and the sensitivity and the detection range of a sensor can be directly controlled by adjusting the proportions and the spraying volume; the application scene of corneal contact lens type intraocular pressure monitoring equipment is further expanded, and the flexibility and variability of the equipment are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible sensors, and in particular relates to a contact lens type intraocular pressure monitoring device with adjustable sensitivity and a preparation method thereof. Background Art

[0002] Intraocular pressure (IOP) is one of the important physiological signals of the human body. It can directly reflect the state of aqueous humor circulation in the eye and can serve as a reliable guide for clinical eye diagnosis. In cases where IOP is significantly increased, such as glaucoma, the change in IOP is not uniform throughout the day. It not only shows a strong biological rhythm, but also the IOP value at night is usually significantly higher than that during the day. In some cases of acute IOP increase, the change in IOP can often reach a high value of 50-60 mmHg, posing new challenges for IOP monitoring. At present, the "Goldman" tonometer is the "gold standard" used in clinical practice. However, it has the disadvantages of not being able to measure continuously, the sensitivity and monitoring range cannot be adjusted, and it relies on the experience of professionals. Therefore, the development of wearable, continuously monitored contact lens-type IOP monitoring equipment is of great significance.

[0003] In the prior art, corneal contact lens-type intraocular pressure monitoring devices generally have problems such as too small monitoring range or too low monitoring sensitivity. In the complex situation of clinical intraocular pressure monitoring, they cannot adapt to the different requirements for high sensitivity and high detection range in different application scenarios. In actual clinical applications, there are great limitations, which affects the application and promotion of contact lens-type intraocular pressure sensors. Summary of the invention

[0004] To solve the above problems, the present invention provides a contact lens-type intraocular pressure monitoring device with adjustable sensitivity and a preparation method thereof. The sensitivity and detection range of the sensor can be directly controlled by adjusting the ratio and the spraying volume, and the application range is wide.

[0005] A contact lens-type intraocular pressure monitoring device with adjustable sensitivity, comprising, from top to bottom, a first flexible packaging layer 31, an elastic sensor substrate 2, a sensor functional unit 1, and a second flexible packaging layer 32;

[0006] The first flexible encapsulation layer 31 and the second flexible encapsulation layer 32 are used to encapsulate the elastic sensor substrate 2 and the sensor functional unit 1; the elastic sensor substrate 2 is used to support the sensor functional unit 1;

[0007] The sensor functional unit 1 is a Wheatstone bridge structure composed of two reference arms and two strain arms, and the sensor functional unit 1 is made of Ti3T2C x The composite conductive material composed of MXene and carboxylated multi-walled carbon nanotubes is sprayed, and Ti3T2C xThe sensitivity and detection range of the sensor functional unit 1 are different due to different ratios between MXene and carboxylated multi-walled carbon nanotubes and different spray volumes of the composite conductive material.

[0008] Further, when the spraying volume of the composite conductive material is 2000 μL, and the mass fractions of the carboxylated multi-walled carbon nanotubes are 0.05%, 0.1%, 0.3%, 0.5%, and 1%, respectively, the sensitivity of the sensor functional unit 1 gradually decreases with the increase of the mass fractions of 0.05%, 0.1%, and 0.3%, and the strain detection range gradually increases with the increase of the mass fractions of 0.05%, 0.1%, and 0.3%;

[0009] During the increase from 0.3% to 0.5%, the sensitivity increases and the strain detection range decreases;

[0010] During the rise from 0.5% to 1%, the sensitivity decreases and the strain detection range decreases.

[0011] Further, when the mass fraction of carboxylated multi-walled carbon nanotubes is 0.3%, and the spraying volumes of the composite conductive material are 500 μL, 1000 μL, 1500 μL, 2000 μL, and 2500 μL, respectively, the sensitivity of the sensor functional unit 1 gradually increases with the increase of the spraying volume of 500 μL, 1000 μL, 1500 μL, and 2000 μL, and the detection range gradually increases with the increase of the mass fraction of 0.05%, 0.1%, and 0.3%;

[0012] During the increase from 2000μL to 2500μL, the sensitivity decreases.

[0013] Further, when the mass fraction of the carboxylated multi-walled carbon nanotubes is 0.3% and the spraying volume of the composite conductive material is 2000 μL, the strain detection range of the sensor functional unit 1 is the largest;

[0014] When the mass fraction of the carboxylated multi-walled carbon nanotubes is 0.5% and the spraying volume of the composite conductive material is 1000 μL, the sensitivity of the sensor functional unit 1 is the highest.

[0015] Furthermore, the material used for the first flexible encapsulation layer 31 and the second flexible encapsulation layer 32 is polydimethylsiloxane.

[0016] Furthermore, the elastic sensor substrate 2 is made of polyvinylidene fluoride (PVFD) polymer material.

[0017] Furthermore, the contact lens type intraocular pressure monitoring device is attached to the simulated eyeball to be tested through the second flexible packaging layer 32, and the sensor functional unit 1 is provided with an external wire interface for leading the intraocular pressure signal of the simulated eyeball to be tested to the host computer.

[0018] A method for preparing a contact lens-type intraocular pressure monitoring device with adjustable sensitivity comprises the following steps:

[0019] S1: spraying a polymer release agent on a glass sheet a and heating and drying;

[0020] S2: spin coating a polymer or hydrogel solution on the glass sheet a treated with a release agent, and obtaining a first flexible encapsulation layer 31 thin film after drying;

[0021] S3: treating the first flexible encapsulation layer 31 film with oxygen plasma under vacuum conditions to temporarily modify the film surface and improve its hydrophilicity;

[0022] S4: spin coating a polymer solution on the modified first flexible encapsulation layer 31 film and heating and drying the film to obtain an elastic sensor substrate 2 attached to the first flexible encapsulation layer 31 film;

[0023] S5: Determine Ti3T2C according to the set sensitivity requirements and strain detection range x The ratio between MXene and carboxylated multi-walled carbon nanotubes, and the volume of the sprayed composite conductive material solution are determined;

[0024] S6: transferring the glass sheet a to a heating platform and continuously heating it, covering the elastic sensor substrate 2 with a mask having a bridge structure, and spraying a composite conductive material solution with a set ratio and volume with a spray gun to obtain a sensor functional unit 1;

[0025] S7: Spin-coating a polymer or hydrogel solution on the sensor functional unit 1, and obtaining a second flexible encapsulation layer 32 thin film after drying;

[0026] S8: The encapsulated integrated film is removed from the glass sheet a, and placed in a mold for hot pressing and molding, thereby completing the preparation of a contact lens-type intraocular pressure monitoring device with adjustable sensitivity.

[0027] Furthermore, Ti3T2C x The mass fraction ratio between MXene and carboxylated multi-walled carbon nanotubes ranges from 1:0.0005 to 1:0.01; the volume of the sprayed composite conductive material solution ranges from 100 μL to 2500 μL.

[0028] Beneficial effects:

[0029] 1. The present invention provides a contact lens-type intraocular pressure monitoring device with adjustable sensitivity, wherein the sensing unit material is Ti3T2C x The composite two-dimensional conductive material made of different ratios of MXene and carboxylated multi-walled carbon nanotubes can directly control the sensitivity and detection range of the sensor by adjusting the ratio and spraying volume, further expanding the application scenarios of corneal contact lens-type intraocular pressure monitoring devices and increasing the flexibility and variability of the equipment.

[0030] 2. The present invention provides a method for preparing a contact lens-type intraocular pressure monitoring device with adjustable sensitivity. The sensing unit is patterned by a simple mask spraying method, and then the contact lens-type intraocular pressure monitoring device with adjustable sensitivity is prepared by hot pressing molding technology. The operation process is relatively simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 1 is a schematic diagram of the structure of a contact lens-type intraocular pressure monitoring device with adjustable sensitivity according to an embodiment of the present invention;

[0032] Figure 2 a is a test result diagram of the influence of the ratio of the composite two-dimensional conductive material with adjustable sensitivity on the sensitivity and detection range of the intraocular pressure sensor in the example of the present invention;

[0033] Figure 2 b is a test result diagram of the influence of the spray volume of the composite two-dimensional conductive material with adjustable sensitivity on the sensitivity and detection range of the intraocular pressure sensor in the example of the present invention;

[0034] Figure 3 Schematic diagram of an intraocular pressure simulation test platform constructed in an embodiment of the present invention;

[0035] Figure 4 a is a dynamic step response curve of the high-sensitivity intraocular pressure sensor in an embodiment of the present invention;

[0036] Figure 4 b is a curve of resistance change (ΔR) and pressure change of the high-sensitivity intraocular pressure sensor in the rising and falling stages in an embodiment of the present invention;

[0037] Figure 5 a is a dynamic step response curve of the wide detection limit intraocular pressure sensor in an embodiment of the present invention;

[0038] Figure 5 b is a curve of resistance change (ΔR) and pressure change of the wide detection limit intraocular pressure sensor in the rising and falling stages in the embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0040] A contact lens-type intraocular pressure monitoring device with adjustable sensitivity, characterized in that it includes, from top to bottom, a first flexible packaging layer 31, an elastic sensor substrate 2, a sensor functional unit 1, and a second flexible packaging layer 32; the sensor substrate 2 is made of polyvinylidene fluoride PVFD polymer material;

[0041] The first flexible encapsulation layer 31 and the second flexible encapsulation layer 32 are used to encapsulate the elastic sensor substrate 2 and the sensor functional unit 1; the elastic sensor substrate 2 is used to support the sensor functional unit 1, that is, the sensor functional unit 1 is located on the elastic sensor substrate 2;

[0042] The sensor functional unit 1 is a Wheatstone bridge structure composed of two reference arms and two strain arms, which are connected and divided by grooves; the groove width is 100 μm; the sensor functional unit 1 is made of Ti3T2C x The composite conductive material composed of MXene and carboxylated multi-walled carbon nanotubes is sprayed, and Ti3T2C x The sensitivity and detection range of the sensor functional unit 1 are different due to different ratios between MXene and carboxylated multi-walled carbon nanotubes and different spray volumes of the composite conductive material.

[0043] It should be noted that the sensor functional unit 1 is a resistive sensor with a power supply interface; the material used for the second flexible packaging layer 32 and the first flexible packaging layer 31 is polydimethylsiloxane. The thickness of the in-eye self-driven intraocular pressure monitoring device is 160μm; the thickness of the sensor substrate 2 is 200nm and the width is 1.2mm; the thickness of the sensor functional unit 1 is 780nm and the width is 1.2mm.

[0044] When the spraying volume of the composite conductive material is 2000 μL, and the mass fractions of carboxylated multi-walled carbon nanotubes are 0.05%, 0.1%, 0.3%, 0.5%, and 1%, respectively, the sensitivity of the sensor functional unit 1 gradually decreases with the increase of the mass fractions of 0.05%, 0.1%, and 0.3%, and the strain detection range gradually increases with the increase of the mass fractions of 0.05%, 0.1%, and 0.3%; in the process of increasing from 0.3% to 0.5%, the sensitivity increases accordingly, and the strain detection range decreases accordingly; in the process of increasing from 0.5% to 1%, the sensitivity decreases accordingly, and the strain detection range decreases accordingly.

[0045] When the mass fraction of carboxylated multi-walled carbon nanotubes is 0.3% and the spraying volumes of the composite conductive material are 500μL, 1000μL, 1500μL, 2000μL, and 2500μL, respectively, the sensitivity of the sensor functional unit 1 gradually increases with the increase of the spraying volume of 500μL, 1000μL, 1500μL, and 2000μL, and the detection range gradually increases with the increase of the mass fraction of 0.05%, 0.1%, and 0.3%; in the process of increasing from 2000μL to 2500μL, the sensitivity decreases accordingly.

[0046] Based on this, when the mass fraction of carboxylated multi-walled carbon nanotubes is 0.3% and the spraying volume of the composite conductive material is 2000 μL, the strain detection range of the sensor functional unit 1 is the largest; when the mass fraction of carboxylated multi-walled carbon nanotubes is 0.5% and the spraying volume of the composite conductive material is 1000 μL, the sensitivity of the sensor functional unit 1 is the highest.

[0047] Furthermore, a method for preparing an in-eye self-driven intraocular pressure monitoring device comprises:

[0048] S1: spraying a polymer release agent on a glass sheet a and heating and drying;

[0049] S2: spin coating a polymer or hydrogel solution on the glass sheet a treated with a release agent, and obtaining a first flexible encapsulation layer 31 thin film after drying;

[0050] S3: treating the first flexible encapsulation layer 31 film with oxygen plasma under vacuum conditions to temporarily modify the film surface and improve its hydrophilicity;

[0051] S4: spin coating a polymer solution on the modified first flexible encapsulation layer 31 film and heating and drying the film to obtain an elastic sensor substrate 2 attached to the first flexible encapsulation layer 31 film;

[0052] S5: Determine Ti3T2C according to the set sensitivity requirements and strain detection range x The ratio between MXene and carboxylated multi-walled carbon nanotubes, and the volume of the sprayed composite conductive material solution are determined;

[0053] S6: transferring the glass sheet a to a heating platform and continuously heating it, covering the elastic sensor substrate 2 with a mask having a bridge structure, and spraying a composite conductive material solution with a set ratio and volume with a spray gun to obtain a sensor functional unit 1;

[0054] S7: Spin-coating a polymer or hydrogel solution on the sensor functional unit 1, and obtaining a second flexible encapsulation layer 32 thin film after drying;

[0055] S8: The encapsulated integrated film is removed from the glass sheet a, and placed in a mold for hot pressing and molding, thereby completing the preparation of a contact lens-type intraocular pressure monitoring device with adjustable sensitivity.

[0056] It should be noted that in step S1, the polymer release agent sprayed is a polysiloxane spray, a fluorine-containing polymer spray, etc.; the release agent is dried at a temperature of 115-125°C for 5-10 minutes. For example, one implementation of step S1 is: spray a polysiloxane spray polymer release agent on a clean glass sheet a and heat and dry it on a heating table at 120°C for 15 minutes to form an adhesion layer on the surface of the glass sheet;

[0057] In step S2, the spin coating solution is a polymer solution or hydrogel solution such as polydimethylsiloxane (PDMS), polybutylene adipate-terephthalate (PBAT), etc. The rotation speed of the spin coating polymer or hydrogel solution to form a film is 500-3000 rpm, and the time is 10-25s. The temperature for drying the first flexible encapsulation layer film is 85-140°C, and the time is 10-30min. For example, one implementation of step S2 is: spin coating a polydimethylsiloxane (PDMS) solution at 1000 rpm on a glass sheet a treated with a release agent for 15s, and heating and drying at 90°C on a heating table for 30min to obtain a first flexible encapsulation layer 31 film;

[0058] In step S3, oxygen plasma treatment is performed under vacuum conditions for 5-15 minutes. For example, one implementation of step S3 is: subjecting the first flexible encapsulation layer 31 film to oxygen plasma treatment under vacuum conditions for 10 minutes to temporarily modify the film surface and improve its hydrophilicity;

[0059] In step S4, the spin coating solution is a polymer solution such as polyvinylidene fluoride (PVFD), an aqueous solution such as waterborne polyurethane (WPU). The rotation speed of the spin coating polymer solution is 1000-2000 rpm, and the time is 10-20s. The temperature of the elastic sensor substrate film is 30-60°C, and the time is 10-30min. For example, one implementation of step S4 is: spin coating the P (VDF-TrFE) polymer solution on the modified first flexible encapsulation layer 31 film at a rotation speed of 2000 rpm for 10s, and drying at 30°C for 20min to obtain a P (VDF-TrFE) polymer film, and obtaining an elastic sensor substrate 2 attached to the first flexible encapsulation layer 31 film;

[0060] In step S4, the solvent of the P(VDF-TrFE) polymer solution is dimethylformamide (DMF) with a concentration of 10%;

[0061] In step S5, Ti3T2C is prepared xThe ratio of MXene and carboxylated multi-walled carbon nanotubes (C-MWCNT) was tested to obtain composite conductive materials with different sensitivities and detection ranges, and further tests were performed to determine the volume of the sprayed composite conductive material solution. x The different ratios of MXene and carboxylated multi-walled carbon nanotubes (C-MWCNT) range from 1:0.0005 to 1:0.01 by mass fraction; the volume of the sprayed composite conductive material ranges from 100 μL to 2500 μL. For example, one implementation of step S5 is: Ti3T2C x The mass ratio of MXene to carboxylated multi-walled carbon nanotubes was 1:0.003, and the intraocular pressure monitoring device prepared with a spraying volume of 2000 μL had the highest sensitivity; Ti3T2C x The intraocular pressure monitoring device prepared with a mass ratio of MXene to carboxylated multi-walled carbon nanotubes of 1:0.005 and a spraying volume of 1500 μL has the widest detection range.

[0062] When spraying the functional material in step S6, the glass sheet should be placed on a heating platform with a temperature of 55-85°C, and the distance between the spray gun and the glass sheet should be 20-40 cm. For example, one implementation of step S6 is: transfer the glass sheet a to the heating platform and continue heating at 65°C, cover the elastic sensor substrate 2 with a mask having a bridge structure, and spray the Ti3T2C x A composite conductive material composed of different ratios of MXene and carboxylated multi-walled carbon nanotubes (C-MWCNT) is obtained to obtain a sensor functional unit 1;

[0063] In step S7, the spin coating solution is a polymer solution or hydrogel solution such as polydimethylsiloxane (PDMS), polybutylene adipate-terephthalate (PBAT), etc. The rotation speed of the spin coating polymer or hydrogel solution to form a film is 500-3000rpm, and the time is 10-25s. The temperature for drying the second flexible encapsulation layer film is 85-140°C, and the time is 10-30min. For example, one implementation of step S7 is: spin coating polydimethylsiloxane (PDMS) solution on the sensor functional unit 1 at 1000rpm for 15s, and heating and drying at 90°C on a heating table for 30min to obtain a second flexible encapsulation layer 32 film;

[0064] In step S8, the temperature of the hot pressing molding is 120-185°C, and the time is 15-50 minutes. For example, one implementation of step S8 is: removing the packaged integrated film from the glass sheet a, placing it in a mold and performing hot pressing molding at 160°C for 30 minutes, thereby completing the preparation of the contact lens-type intraocular pressure monitoring device with adjustable sensitivity;

[0065] For the Ti3T2C mentioned in step S5x Electrochemical performance tests were conducted to investigate the effects of the ratio of MXene and carboxylated multi-walled carbon nanotubes (C-MWCNT) and the volume of the sprayed composite conductive material solution on the sensitivity and detection range of the intraocular pressure monitoring device, including:

[0066] Preparation of test samples: Ti3T2C with good performance was determined through preliminary experiments x The different ratios of MXene and carboxylated multi-walled carbon nanotubes (C-MWCNT) range from 1:0.0005 to 1:0.01 by mass fraction; the volume of the sprayed composite conductive material ranges from 100 μL to 2500 μL. 2000 μL Ti3T2C x MXene@C-MWCNT composite materials, the mass fraction of C-MWCNT is 0.05%, 0.1%, 0.3%, 0.5%, 1%, respectively, after continuous heating and drying at 60°C, spin coating of polydimethylsiloxane (PDMS) solution at 1000rpm for 15s, and heating and drying at 90°C on a heating table for 30min, finally preparing sample a of 0.5mm*2mm. Ti3T2C with a mass fraction of 0.3% of C-MWCNT is sprayed on the modified elastic sensor substrate obtained in step S3. x The MXene@C-MWCNT composite materials were sprayed in volumes of 500 μL, 1000 μL, 1500 μL, 2000 μL, and 2500 μL, respectively. After continuous heating and drying at 60 °C, polydimethylsiloxane (PDMS) solution was spin-coated at 1000 rpm for 15 s and heated and dried at 90 °C on a heating table for 30 min. Finally, sample b of 0.5 mm*2 mm was prepared.

[0067] like Figure 2 As shown in a, as the strain gradually increases, the sensitivity (expressed in this test using ΔR / R) of the test samples made of different C-MWCNTs doping ratios during the test process shows a trend of first increasing and then decreasing, and there is a maximum point. An independent analysis of the ratio with the best sensing performance found that when the C-MWCNTs doping ratio was 0.3%, the sensor had the widest detection range, with a strain of up to 10%; when the doping ratio was increased to 0.5%, the sensitivity of the sensor was 186.6% at a tensile strain of 5.6%, demonstrating its superior sensing performance.

[0068] like Figure 2 As shown in b, with the gradual increase of strain, the xThe sensitivity of the test samples made of MXene@0.3%-C-MWCNT composite spray volume during the test (expressed in this test using ΔR / R) showed a trend of first increasing and then decreasing, and there was a maximum point. An independent analysis of the spray volume with the best sensing performance found that: when Ti3T2C x The highest sensitivity can be obtained when the spraying volume of MXene@0.3%-C-MWCNT composite material is 2000μL, and the maximum sensing detection range can be obtained when the spraying volume is 1000μL.

[0069] The results of the comparative experiments show that different C-MWCNTs doping ratios and different Ti3T2C x The spray volume of MXene@0.3%-C-MWCNT composite material can jointly affect the detection range and sensitivity of the sensor. Combining different spray volumes of materials with different ratios can obtain a wide range of adjustable sensitivity and detection range, so it can be well adapted to different detection environments and application scenarios. In summary, the test results fully demonstrate that by simply adjusting the Ti3T2C x The conclusion that the sensitivity and detection range of the sensor can be successfully regulated by adjusting the mass fraction of C-MWCNT in the MXene@C-MWCNT composite material and the spraying volume of the composite material provides theoretical support for the preparation process of adjustable corneal contact lens-type intraocular pressure monitoring equipment. At the same time, through the analysis of further test results, we can also find the optimal spraying ratio and spraying volume by controlling the variable method. x The best performance wide detection range sensor can be obtained by spraying 2000 μL of MXene@0.3%-C-MWCNT composite material, Ti3T2C x The best performance of high-sensitivity sensor can be obtained by spraying 1000 μL of MXene@0.5%-C-MWCNT composite material.

[0070] According to the optimal ratio and spraying volume obtained in step S5, the electrochemical performance test of the high-sensitivity intraocular pressure monitoring device and the wide detection limit intraocular pressure monitoring device obtained by the present invention is performed, including:

[0071] Build as Figure 3The intraocular pressure testing platform shown is composed of an artificial simulated eyeball, a stepping motor, a liquid bag, a commercial pressure gauge and a test source meter; the liquid bag is suspended on the stepping motor and moves with the stepping motor to control the height of the liquid bag; the liquid bag is connected to the artificial simulated eyeball, and the liquid pressure is changed by changing the height of the liquid bag to control the pressure inside the artificial simulated eyeball; the other end of the artificial simulated eyeball is connected to a commercial pressure gauge to test the pressure inside the artificial simulated eyeball; the corneal contact lens type intraocular pressure monitoring device obtained by the present invention is placed on the artificial simulated eyeball to sense the pressure changes inside the artificial simulated eyeball; the test source meter is connected to four pins of the corneal contact lens type intraocular pressure monitoring device, two pins are used to power the sensor composed of the sensor substrate 2 obtained in step S4 and the sensor functional unit 1 obtained in step S6, and the other two pins are used to collect the corresponding output voltage of the device.

[0072] Electrochemical performance test of high-sensitivity contact lens intraocular pressure sensor:

[0073] The sensor composed of the sensor substrate 2 obtained in step S4 and the sensor functional unit 1 obtained in step S6 is powered by a test source meter, and the height of the liquid bag is changed by a stepper motor to control the dynamic step of the pressure in the artificial simulated eyeball within the range of 0-30 mmHg, that is, the pressure is paused for 10 seconds every time it rises by 3.75 mmHg. Figure 4 The voltage response ΔV shown in a can well match the pressure change, proving the good response rate of the intraocular pressure monitoring device. The step image shown in the figure can achieve symmetrical distribution of the rising and falling parts, proving that the intraocular pressure monitoring device has good deformation recovery ability.

[0074] right Figure 4 The pressure and voltage changes at each pause in a are linearly fitted. Figure 4 The fitting curve of the voltage response ΔV change with the pressure in b shows that the voltage change of the sensor has an excellent linear relationship with the pressure during the application of increasing and decreasing pressure. The sensor composed of the sensor substrate 2 obtained in step S4 and the sensor functional unit 1 obtained in step S6 has stable performance during the rise and fall of intraocular pressure. During the rise process, the sensitivity reaches 33.21mV / mmHg, and the linear regression coefficient R 2 is 0.99426. During the decline, the sensitivity reaches 32.78mV / mmHg, and the linear regression coefficient R 2 The sensitivity fluctuation in the two processes was only 0.13%, indicating that the high-sensitivity corneal contact lens intraocular pressure sensor has good reproducibility and stability.

[0075] Electrochemical performance testing of wide detection limit contact lens intraocular pressure sensor:

[0076] The sensor composed of the sensor substrate 2 obtained in step S4 and the sensor functional unit 1 obtained in step S6 is powered by a test source meter, and the height of the liquid bag is changed by a stepper motor to control the dynamic step of the pressure in the artificial simulated eyeball within the range of 0-60 mmHg, that is, the pressure is paused for 10 seconds every time it rises by 7.5 mmHg. Figure 5 The voltage response ΔV shown in a can well match the pressure change, proving the good response rate of the intraocular pressure monitoring device. The step image shown in the figure can achieve symmetrical distribution of the rising and falling parts, proving that the intraocular pressure monitoring device has good deformation recovery ability.

[0077] right Figure 5 The pressure and voltage changes at each pause in a are linearly fitted. Figure 5 The fitting curve of the voltage response ΔV change with the pressure in b shows that the voltage change of the sensor has an excellent linear relationship with the pressure during the application of increasing and decreasing pressure. The sensor composed of the sensor substrate 2 obtained in step S4 and the sensor functional unit 1 obtained in step S6 has stable performance during the rise and fall of intraocular pressure. During the rise process, the sensitivity reaches 1.495mV / mmHg, and the linear regression coefficient R 2 is 0.99571. During the decline, the sensitivity reaches 1.523mV / mmHg, and the linear regression coefficient R 2 The sensitivity fluctuation in the two processes was only 0.18%, indicating that the high-sensitivity corneal contact lens intraocular pressure sensor has good reproducibility and stability.

[0078] The unique advantage of the corneal contact lens intraocular pressure sensor in this work is that the sensitivity and maximum detection limit can be adjusted by using a simple strategy, which means that it can be adapted to more complex application scenarios. The electrochemical performance test results of two typical examples show that the sensor composed of the sensor substrate 2 obtained in step S4 and the sensor functional unit 1 obtained in step S6 has stable performance and good repeatability, achieving the requirements of adjustable sensitivity and detection range.

[0079] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may certainly make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A contact lens-type intraocular pressure monitoring device with adjustable sensitivity, characterized in that: It comprises, from top to bottom, a first flexible packaging layer (31), an elastic sensor substrate (2), a sensor functional unit (1), and a second flexible packaging layer (32); The first flexible encapsulation layer (31) and the second flexible encapsulation layer (32) are used to encapsulate the elastic sensor substrate (2) and the sensor functional unit (1); the elastic sensor substrate (2) is used to support the sensor functional unit (1); The sensor functional unit (1) is a Wheatstone bridge structure composed of two reference arms and two strain arms, and the sensor functional unit (1) is made of Ti3T2C x The composite conductive material composed of MXene and carboxylated multi-walled carbon nanotubes is sprayed, and Ti3T2C x The sensitivity and detection range of the sensor functional unit (1) are different due to different ratios between MXene and carboxylated multi-walled carbon nanotubes and different spray volumes of the composite conductive material.

2. A contact lens type intraocular pressure monitoring device with adjustable sensitivity as claimed in claim 1, characterized in that: When the spraying volume of the composite conductive material is 2000 μL, and the mass fractions of the carboxylated multi-walled carbon nanotubes are 0.05%, 0.1%, 0.3%, 0.5%, and 1%, respectively, the sensitivity of the sensor functional unit (1) gradually decreases with the increase of the mass fractions of 0.05%, 0.1%, and 0.3%, and the strain detection range gradually increases with the increase of the mass fractions of 0.05%, 0.1%, and 0.3%. During the increase from 0.3% to 0.5%, the sensitivity increases and the strain detection range decreases; During the rise from 0.5% to 1%, the sensitivity decreases and the strain detection range decreases.

3. A contact lens type intraocular pressure monitoring device with adjustable sensitivity as claimed in claim 1, characterized in that: When the mass fraction of carboxylated multi-walled carbon nanotubes is 0.3%, and the spraying volumes of the composite conductive material are 500 μL, 1000 μL, 1500 μL, 2000 μL, and 2500 μL, respectively, the sensitivity of the sensor functional unit (1) gradually increases with the increase of the spraying volume of 500 μL, 1000 μL, 1500 μL, and 2000 μL, and the detection range gradually increases with the increase of the mass fraction of 0.05%, 0.1%, and 0.3%. During the increase from 2000μL to 2500μL, the sensitivity decreases.

4. A contact lens type intraocular pressure monitoring device with adjustable sensitivity as claimed in any one of claims 1 to 3, characterized in that: When the mass fraction of carboxylated multi-walled carbon nanotubes is 0.3% and the spraying volume of the composite conductive material is 2000 μL, the strain detection range of the sensor functional unit (1) is the largest; When the mass fraction of the carboxylated multi-walled carbon nanotubes is 0.5% and the spraying volume of the composite conductive material is 1000 μL, the sensitivity of the sensor functional unit (1) is the highest.

5. The contact lens type intraocular pressure monitoring device with adjustable sensitivity as claimed in claim 1, characterized in that: The material used for the first flexible packaging layer (31) and the second flexible packaging layer (32) is polydimethylsiloxane.

6. The contact lens type intraocular pressure monitoring device with adjustable sensitivity as claimed in claim 1, characterized in that: The elastic sensor substrate (2) is made of polyvinylidene fluoride (PVFD) polymer material.

7. The contact lens type intraocular pressure monitoring device with adjustable sensitivity as claimed in claim 1, characterized in that: The contact lens type intraocular pressure monitoring device is attached to the simulated eyeball to be tested via a second flexible packaging layer (32), and the sensor functional unit (1) is provided with an external wire interface for leading the intraocular pressure signal of the simulated eyeball to be tested to a host computer.

8. A method for preparing a contact lens-type intraocular pressure monitoring device with adjustable sensitivity, characterized in that: The following steps are involved: S1: spraying a polymer release agent on a glass sheet a and heating and drying; S2: spin coating a polymer or hydrogel solution on the glass sheet a treated with a release agent, and obtaining a first flexible encapsulation layer (31) thin film after drying; S3: treating the first flexible encapsulation layer (31) thin film with oxygen plasma under vacuum conditions to temporarily modify the surface of the thin film to improve its hydrophilicity; S4: spin coating a polymer solution on the modified first flexible encapsulation layer (31) film and heating and drying the film to obtain an elastic sensor substrate (2) attached to the first flexible encapsulation layer (31) film; S5: Determine Ti3T2C according to the set sensitivity requirements and strain detection range x The ratio between MXene and carboxylated multi-walled carbon nanotubes, and the volume of the sprayed composite conductive material solution are determined; S6: transferring the glass sheet a to a heating table for continuous heating, covering the elastic sensor substrate (2) with a mask having a bridge structure, and spraying a composite conductive material solution of a set ratio and volume with a spray gun to obtain a sensor functional unit (1); S7: spin coating a polymer or hydrogel solution on the sensor functional unit (1), and obtaining a second flexible encapsulation layer (32) thin film after drying; S8: The encapsulated integrated film is removed from the glass sheet a, and placed in a mold for hot pressing and molding, thereby completing the preparation of a contact lens-type intraocular pressure monitoring device with adjustable sensitivity.

9. The method for preparing a contact lens-type intraocular pressure monitoring device with adjustable sensitivity as claimed in claim 8, characterized in that: Ti3T2C x The mass fraction ratio between MXene and carboxylated multi-walled carbon nanotubes ranges from 1:0.0005 to 1:0.01; the volume of the sprayed composite conductive material solution ranges from 100 μL to 2500 μL.

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