Microfluidic intraocular pressure sensor based on double-sided wall structure and preparation method thereof

Abstract

A microfluidic intraocular pressure (IOP) sensor based on a double-sidewall structure and its fabrication method are disclosed, which can be applied in the field of IOP sensing. The sensor includes: a corneal contact lens for transmitting changes in intraocular pressure; the corneal contact lens includes a planar sensing layer and a support structure; a sensing and display cavity is disposed within the planar sensing layer, the sensing and display cavity being spirally distributed around the center of the planar sensing layer for sensing and indicating changes in intraocular pressure; the support structure maintains a preset first curvature for the corneal contact lens. The sensing and display cavity includes: a sensing fluid cavity disposed on the outer ring of the planar sensing layer, one end of which is closed, and the other end connected to a display channel; the sensing fluid cavity is provided with a double-sidewall structure and is filled with an indicator fluid, the volume of which changes in response to changes in intraocular pressure; the display channel is connected at one end to the sensing fluid cavity and at the other end to a buffer chamber for displaying the displacement of the indicator fluid to indicate changes in intraocular pressure; the buffer chamber is connected at one end to the display channel and at the other end closed for balancing air pressure changes.

Description

Technical Field

[0001] This disclosure relates to the field of intraocular pressure sensing, and in particular to a microfluidic intraocular pressure sensor based on a double-sided wall structure and its fabrication method. Background Technology

[0002] Glaucoma is the leading cause of irreversible blindness worldwide. Early diagnosis and screening combined with targeted treatment are the best methods to slow the further progression of this disease. Pathologically elevated intraocular pressure (IOP) is the main pathogenic factor of glaucoma. IOP refers to the pressure exerted by the contents of the eyeball on the inner wall of the eye. When the production and drainage of aqueous humor are in balance, IOP is stable; when the aqueous humor drainage system is blocked, IOP rises, compressing the optic nerve and causing damage. IOP is affected not only by circadian rhythms but also by factors such as body posture, movement, and eye fixation tasks.

[0003] Existing intraocular pressure (IOP) measurement devices can measure IOP using methods such as flattening or entropion, achieving a single, highly accurate measurement within a fixed location and time period. However, these devices are operated by professionals and may miss dangerous IOP fluctuations, leading to inaccurate disease assessments and inappropriate treatment plans. Therefore, there is a need for an IOP measurement device that can continuously and accurately monitor IOP without time or space limitations.

[0004] Existing intraocular pressure (IOP) sensors can be divided into implantable and non-implantable types. Implantable IOP sensors are inserted into the eye through ophthalmic surgery to directly sense changes in intraocular pressure, offering high sensitivity and accuracy; however, the surgery increases the risk of eye trauma and infection. Non-implantable IOP sensors embed the sensing element within a contact lens, using the lens to detect changes in eye and corneal deformation, thus indirectly sensing changes in IOP. This method does not require surgical implantation, causing less harm to the eye and better meeting practical needs. However, this method has relatively lower accuracy and sensitivity, and because it primarily relies on electronic components for sensing, a mechanical mismatch between the electronic component and the cornea is unavoidable, potentially leading to corneal damage with prolonged use. Summary of the Invention

[0005] In view of this, the main objective of this disclosure is to provide a microfluidic intraocular pressure sensor based on a dual-sidewall structure and a method for fabricating the same, in order to partially solve at least one of the aforementioned technical problems.

[0006] To achieve the above objectives, one aspect of this disclosure provides a microfluidic intraocular pressure sensor based on a dual-sidewall structure. The microfluidic intraocular pressure sensor includes:

[0007] A corneal contact lens is used to transmit changes in intraocular pressure, which are generated by the target eye.

[0008] The aforementioned corneal contact lens includes: a planar sensing layer and a support structure located between the planar sensing layer and the target eyeball;

[0009] The aforementioned planar sensing layer contains a sensing and display cavity, which is spirally distributed around the center of the planar sensing layer, for sensing and indicating the changes in intraocular pressure; and

[0010] The aforementioned support structure is used to maintain the aforementioned corneal contact lens at a preset first curvature;

[0011] The aforementioned sensing and display cavity includes: a sensing liquid cavity, a display channel, and a buffer chamber;

[0012] The aforementioned sensing liquid cavity is located on the outer ring of the aforementioned planar sensing layer away from the aforementioned center, with one end closed and the other end connected to the aforementioned display channel. A preset number of double-sided wall structures are provided inside the aforementioned sensing liquid cavity. The aforementioned sensing liquid cavity is filled with indicator liquid, which is used to change the volume of the aforementioned sensing liquid cavity in response to the aforementioned change in intraocular pressure.

[0013] One end of the aforementioned display channel is connected to the aforementioned sensing fluid chamber, and the other end is connected to the aforementioned buffer chamber, for displaying the displacement of the aforementioned indicator fluid, so as to display the aforementioned intraocular pressure change;

[0014] One end of the aforementioned buffer chamber is connected to the aforementioned display channel, which is used to balance the pressure changes caused by the volume changes of the aforementioned sensing liquid chamber.

[0015] According to an embodiment of this disclosure, the cross-section of the sensing fluid cavity is a first rectangle;

[0016] The aforementioned sensing fluid cavity is provided with a predetermined number of the aforementioned double-sided wall structures, and the spacing between adjacent aforementioned double-sided wall structures is equal.

[0017] The aforementioned double-sided wall structure includes dividing the cavity of the aforementioned sensing liquid cavity into three parallel sub-cavities, which are connected at the intervals between the aforementioned double-sided wall structures.

[0018] According to embodiments of this disclosure, the cavity of the sensing liquid chamber is filled with the indicator liquid; and

[0019] In response to the change in intraocular pressure, the volume of the sensing fluid chamber changes, and the indicator fluid is either discharged or recovered.

[0020] According to an embodiment of this disclosure, the cross-section of the display channel is a second rectangle, and the area of ​​the second rectangle is 1 / 10 of the area of ​​the first rectangle.

[0021] According to embodiments of this disclosure, the planar sensing layer includes a first thin film and a second thin film;

[0022] The first film mentioned above is a patternless smooth film;

[0023] The side of the second film that contacts the first film includes a patterned groove; and

[0024] The first film and the second film are bonded together after plasma treatment;

[0025] The patterned groove, which is sealed after being attached, constitutes the aforementioned sensing and display cavity.

[0026] According to an embodiment of this disclosure, the planar sensing layer and the support structure are made of the same material, and pressure is applied to the planar sensing layer and the support structure to make them adhere together.

[0027] According to embodiments of this disclosure, the microfluidic intraocular pressure sensor further includes:

[0028] A bend with a preset second curvature is provided at the connection between the aforementioned sensing fluid cavity and the aforementioned display channel; and

[0029] A bend with a preset second curvature is provided at the connection between the above-mentioned display channel and the above-mentioned buffer chamber.

[0030] According to embodiments of this disclosure, the microfluidic intraocular pressure sensor further includes:

[0031] The radius of curvature of the aforementioned corneal contact lenses is 8-12 mm;

[0032] The aforementioned sensing display cavity is disposed within the internal region of the planar sensing layer, which is defined by an outer ring and an inner ring. The outer ring is a circular ring with a curved surface length of 2 mm from the edge of the planar sensing layer, and the inner ring is a circular ring with a curved surface length of 5 mm from the center.

[0033] The radius of curvature of the aforementioned support structure is the same as the radius of curvature of the outer concave side of the aforementioned corneal contact lens.

[0034] Another aspect of this disclosure provides a method for fabricating a microfluidic intraocular pressure sensor based on a dual-sidewall structure. The fabrication method includes:

[0035] A first mold with a sensing display cavity size is prepared on a silicon wafer by photolithography. The sensing display cavity includes a sensing liquid cavity, a display channel, and a buffer chamber.

[0036] A liquid flexible polymer solution is spin-coated onto a second mold and the first mold to obtain a non-patterned second film and a patterned first film.

[0037] The first thin film and the second thin film are subjected to plasma treatment to bond the first thin film and the second thin film together to obtain a cavity structure of a planar sensing layer.

[0038] The aforementioned liquid flexible polymer solution is drop-coated onto the surface of a copper mold with a preset curvature. When the liquid flexible polymer solution is in a semi-solid state, it is bonded to the cavity structure of the planar sensing layer to obtain a composite material. This composite material is then pressed to obtain the cavity structure of the microfluidic intraocular pressure sensor based on a dual-sidewall structure.

[0039] The indicator fluid is filled into the sensing fluid cavity and the display channel through the injection port, and the injection port is sealed with flexible silicone adhesive to prevent the indicator fluid from flowing back, thus obtaining the microfluidic intraocular pressure sensor based on the double-sidewall structure.

[0040] According to embodiments of this disclosure, the flexible polymer solution includes one of: polydimethylsiloxane, flexible silicone hydrogel, polydimethylsiloxane-modified polymer, or flexible silicone hydrogel-modified polymer.

[0041] Based on the above technical solutions, it can be seen that the embodiments of this disclosure have the following beneficial effects compared with the prior art:

[0042] When a contact lens transmits changes in intraocular pressure (IOP) to the sensing display cavity, the sensing fluid cavity within the cavity senses these changes, and its volume changes accordingly. Because the sensing fluid cavity contains a predetermined number of sidewall structures, these structures serve to divide the cavity into zones and provide support, ensuring more uniform force distribution when the sensing fluid cavity senses IOP changes. This results in a more accurate correlation between the IOP change sensed by the sensing fluid cavity and the resulting deformation. The volume change of the sensing fluid cavity after deformation causes displacement of the indicator fluid within the display channel. Based on this displacement, the IOP change can be numerically represented, thus achieving highly accurate IOP sensing.

[0043] In addition, a predetermined number of double-sided wall structures are set in the sensing fluid cavity, which can provide certain support for the cavity during the actual fabrication of the intraocular pressure sensor, thereby improving the sensor fabrication rate. Attached Figure Description

[0044] Figure 1 The schematic diagram illustrates a microfluidic intraocular pressure sensor based on a dual-sidewall structure according to an embodiment of the present disclosure.

[0045] Figure 2 A schematic diagram of a microfluidic intraocular pressure sensor based on a dual-sidewall structure according to another embodiment of the present disclosure is shown.

[0046] Figure 3 A flowchart illustrating a method for fabricating a microfluidic intraocular pressure sensor based on a dual-sidewall structure according to an embodiment of the present disclosure is shown.

[0047] Figure 4 The schematic diagram illustrates a step-by-step flowchart of a method for fabricating a microfluidic intraocular pressure sensor based on a dual-sidewall structure according to an embodiment of the present disclosure.

[0048] Figure 5 A schematic diagram illustrating the relationship between gas-liquid interface displacement and pressure according to an embodiment of the present disclosure is shown. Detailed Implementation

[0049] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0050] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0051] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0052] When using expressions such as "at least one of A, B, and C", the expression should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B, and C, etc.).

[0053] In realizing the concept of this disclosure, the inventors discovered at least the following problems in the related technology:

[0054] Existing non-implantable intraocular pressure sensors embed sensing elements within contact lenses, using the contact lens to transmit changes in eye and corneal deformation, which are then indirectly sensed by the sensing element to detect changes in intraocular pressure. However, this method has relatively low accuracy and sensitivity, and since it primarily relies on electronic components for sensing, there may be a mechanical mismatch between the electronic components and the cornea, potentially leading to corneal damage with prolonged use.

[0055] To at least partially address the existing technical problems, this disclosure provides a microfluidic intraocular pressure sensor based on a dual-sidewall structure and its fabrication method. It can be applied to the field of intraocular pressure sensing.

[0056] Figure 1 The schematic diagram illustrates a microfluidic intraocular pressure sensor based on a dual-sidewall structure according to an embodiment of the present disclosure.

[0057] like Figure 1 As shown, the microfluidic intraocular pressure sensor based on a dual-sidewall structure includes: a corneal contact lens 1.

[0058] A corneal contact lens 1 is used to transmit changes in intraocular pressure generated by the target eye. The corneal contact lens includes a planar sensing layer and a support structure located between the planar sensing layer and the target eye.

[0059] The planar sensing layer contains a sensing and display cavity, which is spirally distributed around the center of the planar sensing layer to sense and display changes in intraocular pressure.

[0060] According to embodiments of this disclosure, the sensing display cavity includes: a sensing liquid cavity 2, a display channel 3, and a buffer chamber 4.

[0061] The sensing liquid chamber 2 is located in the outer ring of the planar sensing layer away from the center. One end is closed and the other end is connected to the display channel. A preset number of double-sided wall structures 5 are provided in the sensing liquid chamber, and the sensing liquid chamber is filled with indicator liquid 6.

[0062] The sensing liquid cavity 2 is used to change its volume in response to changes in intraocular pressure, so that the indicator liquid 6 in the sensing liquid cavity 2 is squeezed and moves towards the display channel 3, thereby changing the displacement of the indicator liquid 6 at the gas-liquid interface 7 of the display channel 3.

[0063] One end of the display channel 3 is connected to the sensing fluid chamber 2, and the other end is connected to the buffer chamber 4. It is used to display the displacement of the indicator fluid 6 so as to show the change in intraocular pressure.

[0064] One end of the buffer chamber 4 is connected to the display channel 3, and the other end is closed, which is used to balance the air pressure change caused by the volume change of the sensing liquid chamber 2.

[0065] According to embodiments of this disclosure, the microfluidic intraocular pressure sensor based on a dual-sidewall structure further includes a support structure.

[0066] The support structure is positioned between the planar sensing layer and the target eyeball, that is, in Figure 1 The microfluidic intraocular pressure sensor shown, based on a dual-sidewall structure, has a support structure on its back. The support structure is tightly bonded to the planar sensing layer on the concave side of the corneal contact lens to maintain the corneal contact lens at a preset first curvature.

[0067] According to embodiments of this disclosure, the specific value of the preset first curvature can be the curvature of the target eyeball, so that the corneal contact lens maintains the same curvature as the target eyeball, thereby improving the comfort of wearing the microfluidic intraocular pressure sensor based on the dual-sidewall structure.

[0068] Understandably, in Figure 1 From the perspective of the sensor, the supporting structure is covered by the planar sensing layer, so the supporting structure cannot be observed directly.

[0069] According to embodiments of this disclosure, the sensing fluid cavity 2 in the sensing display cavity senses changes in intraocular pressure transmitted by the corneal contact lens, and its volume changes accordingly. Since the sensing fluid cavity 2 is provided with a predetermined number of sidewall structures 5, the sidewall structures 5 can divide the area and provide support, making the force on the sensing fluid cavity 2 more uniform when it senses changes in intraocular pressure. This results in a more accurate correspondence between the intraocular pressure change sensed by the sensing fluid cavity 2 and the deformation that occurs after sensing the intraocular pressure change. The volume change of the sensing fluid cavity 2 after deformation causes the indicator fluid 6 within the sensing fluid cavity 2 to shift. The displacement of the indicator fluid 6 allows for a numerical representation of the intraocular pressure change, thereby achieving highly sensitive intraocular pressure sensing.

[0070] According to the embodiments of this disclosure, since the sensing liquid cavity 2 has a wide cavity cross-sectional diameter, when setting the sensing liquid cavity 2, it can be set as a discontinuous ring, with one end of the discontinuous ring closed and the other end connected to the display channel 3.

[0071] like Figure 1 As shown, the planar sensing layer can be divided into multiple regions by a preset angular scale, and the two ends of the sensing fluid cavity 2 can be placed in the same region when setting the regions. In the remaining regions, each region can be equipped with one double-sided wall structure 5.

[0072] According to an embodiment of this disclosure, a double-sided wall structure 5 includes two supporting walls, the distance between the two supporting walls and the distance between each of the two supporting walls and the cavity wall of its adjacent sensing liquid cavity 2 are equal.

[0073] Since the double-sided wall structure 5 is set in the sensing liquid cavity 2 with a certain curvature, each double-sided wall structure 5 includes two supporting walls that are arc-shaped walls with curvature approximately or equal to that of the sensing liquid cavity 2.

[0074] A double-sided wall structure 5 divides the cavity of the sensing fluid chamber 2 into three parallel sub-cavities. The three parallel sub-cavities are connected at the end of the double-sided wall structure 5, that is, the three parallel sub-cavities are connected at the interval between the double-sided wall structure 5 in which they are located and the adjacent double-sided wall structure 5.

[0075] According to embodiments of this disclosure, when the interval is divided at a 45° angular scale, the spacing between adjacent double-sided wall structures 5 can be the length of the sensing liquid cavity 2 corresponding to a 2° angle. Alternatively, the interval can be divided at a 60° angular scale, and the spacing between the corresponding double-sided wall structures 5 can be adjusted according to actual conditions, but is not limited thereto. Embodiments of this disclosure do not limit the specific number of double-sided wall structures 5 or the spacing between them; those skilled in the art can design according to actual needs.

[0076] According to embodiments of this disclosure, the microfluidic intraocular pressure sensor based on a dual-sidewall structure further includes:

[0077] The curved radius of the corneal contact lens is 8-12mm; the sensing and display cavity is located inside the planar sensing layer, which is limited by an outer ring and an inner ring. The outer ring is a ring with a curved length of 2mm from the edge of the planar sensing layer, and the inner ring is a ring with a curved length of 5mm from the center; the curved radius of the support structure is the same as the curved radius of the outer concave side of the corneal contact lens.

[0078] According to embodiments of this disclosure, the radius of curvature of the corneal contact lens is primarily set based on the radius of curvature of the eyeball. The curvature of the corneal contact lens can approximate the curvature of the eyeball, with a radius of curvature between 8 and 12 mm. To ensure comfort when actually wearing the intraocular pressure sensor and to consider the success rate of intraocular pressure sensor fabrication, the thickness of the corneal contact lens can be set to 200 μm to 400 μm.

[0079] According to embodiments of this disclosure, the size of the inner ring should be set so as not to obstruct the pupil from acquiring external light signals. Those skilled in the art can design it according to actual needs, and no limitations are imposed here.

[0080] According to the embodiments of this disclosure, since the cross-sectional diameter of the display channel 3 cavity is smaller than that of the sensing liquid cavity 2, and the display channel 3 is responsible for displaying the change in intraocular pressure, it is necessary to set the display channel 3 cavity to have a sufficient display length. In this embodiment, the display channel 3 can be set as a spiral-distributed annular cavity of 1.5 to 2 turns.

[0081] According to the embodiments of this disclosure, after setting the specific location and specific cross-sectional diameter of the sensing display cavity and the display channel 3 cavity, those skilled in the art can design the specific location and specific cross-sectional diameter of the buffer chamber 4 according to actual needs, and this disclosure does not impose specific limitations.

[0082] Figure 2 A schematic diagram of a microfluidic intraocular pressure sensor based on a dual-sidewall structure according to another embodiment of the present disclosure is shown.

[0083] You can set to Figure 1The schematically illustrated microfluidic intraocular pressure sensor based on a double-sided wall structure is symmetrically cut to obtain, as shown below. Figure 2 The diagram shows a cross-sectional view of a microfluidic intraocular pressure sensor based on a dual-sidewall structure.

[0084] According to embodiments of this disclosure, the cross-section of the sensing fluid cavity 2 is a first rectangle. The cross-section of the walls in the double-wall structure 5 is a solid rectangle. Figure 2 As shown, the left-side sensing liquid chamber 2 is divided into three parallel sub-chambers by a double-sided wall structure 5, and the right-side sensing liquid chamber 2 is divided into three parallel sub-chambers by another double-sided wall structure 5. The three parallel sub-chambers of the left-side sensing liquid chamber 2 are connected at the end of the corresponding double-sided wall structure 5, that is, the three parallel sub-chambers are connected at the interval between the double-sided wall structure 5 and its adjacent double-sided wall structure 5. The interval double-sided wall structure 5 is used to ensure that the indicating liquid 6 fills the sub-chambers uniformly and can reduce the generation of air bubbles.

[0085] The connection relationships between the three parallel sub-cavities of the sensing liquid cavity 2, which are divided by the double-sided wall structure 5, are the same or similar, and will not be described in detail here.

[0086] According to embodiments of this disclosure, the length of the sensing liquid cavity 2 in the plane containing the circular shape of the planar sensing layer can be set as the length of the cross-section of the sensing liquid cavity 2, and the length of the sensing liquid cavity 2 in the thickness direction of the corneal contact lens can be set as the height of the cross-section of the sensing liquid cavity 2. The definitions of length and height can also be applied to the display channel 3 and the buffer chamber 4. In one embodiment, the cross-section of the sensing liquid cavity 2 can be set as a rectangle with a length of 450 μm and a height of 100 μm, and the double-side wall structure 5 provided in the sensing liquid cavity 2 includes two solid rectangular walls with a cross-section of 75 μm in length and 100 μm in height.

[0087] like Figure 2 As shown, the sensing fluid chamber 2 is filled with indicator fluid 6. In response to changes in intraocular pressure, the sensing fluid chamber 2 changes its volume, discharging or retrieving the indicator fluid 6.

[0088] According to the embodiments of this disclosure, the indicator liquid 6 can be ink, dyed glycerin, or sodium solution doped with pigment. The embodiments of this disclosure do not limit the specific type of indicator liquid 6, and those skilled in the art can select it according to actual needs.

[0089] According to an embodiment of this disclosure, in response to changes in intraocular pressure, the volume of the sensing liquid cavity 2 can be changed, which can cause the gas-liquid interface 7 in the display channel 3 to shift. By detecting the position of the gas-liquid interface 7, the intraocular pressure can be visualized.

[0090] like Figure 2 As shown, channel 3 has a cross-section of the second rectangle.

[0091] According to the embodiments of this disclosure, after the sensing liquid cavity 2 senses a change in intraocular pressure, such as an increase in intraocular pressure, the sensing liquid cavity 2 is stretched by pressure, causing the indicator liquid 6 in the display channel 3 to flow to the sensing liquid cavity 2. This allows for the displacement of the gas-liquid interface 7 corresponding to the indicator liquid 6 in the display channel 3. To make the change of the indicator liquid 6 in the display channel 3 more obvious, the cross-sectional diameter of the display channel 3 should be smaller than the cross-sectional diameter of the sensing liquid cavity 2.

[0092] According to embodiments of this disclosure, in order for the display channel 3 to amplify the display of intraocular pressure changes, the cross-sectional area of ​​the display channel 3 can be set to be at least half the cross-sectional area of ​​the sensing fluid cavity 2. Furthermore, considering manufacturing processes, a display channel 3 with too small a cross-section would increase manufacturing difficulty and compromise dimensional accuracy. Therefore, the cross-sectional area of ​​the display channel 3 can be set to 1 / 10 of the cross-sectional area of ​​the location in the sensing fluid cavity 2 where the double-sidewall structure 5 exists, achieving the effect of amplifying the display of intraocular pressure changes while also considering the achievable range of cross-sectional area within the limits of manufacturing capabilities.

[0093] In one embodiment, when the sensing liquid cavity 2 has a rectangular cross-section of 450 μm in length and 100 μm in height, and the double-side wall structure 5 in the sensing liquid cavity 2 includes two solid rectangular walls with a cross-section of 75 μm in length and 100 μm in height, the display channel 3 can be set to have a rectangular cross-section of 60 μm in width and 50 μm in height.

[0094] According to an embodiment of this disclosure, when the volume of the sensing liquid cavity 2 changes in response to changes in intraocular pressure, the pressure in the closed sensing display cavity changes. To reduce the risk of damage to the closed sensing display cavity caused by drastic changes in the volume of the sensing liquid cavity 2, a buffer chamber 4 is provided to balance the pressure change in the chamber caused by changes in the volume of the sensing liquid cavity 2.

[0095] In one embodiment, the buffer chamber 4 can be configured as a rectangle with a length of 200 μm and a height of 100 μm.

[0096] According to embodiments of this disclosure, the planar sensing layer may include a first thin film and a second thin film.

[0097] The second film is a smooth, unpatterned film; the side of the first film that contacts the second film includes a patterned groove; the first and second films are bonded together after plasma treatment. The patterned groove, sealed after bonding, constitutes the sensing display cavity.

[0098] According to embodiments of this disclosure, plasma treatment can be oxygen plasma treatment. The embodiments of this disclosure do not limit the specific type of plasma treatment, and those skilled in the art can select according to actual needs.

[0099] According to embodiments of this disclosure, the microfluidic intraocular pressure sensor based on a dual-sidewall structure further includes the following structure:

[0100] A bend with a preset second curvature is provided at the connection between the sensing liquid chamber 2 and the display channel 3; a bend with a preset second curvature is provided at the connection between the display channel 3 and the buffer chamber 4.

[0101] According to embodiments of this disclosure, a bend with a preset second curvature and a small curvature is provided at the connection between the sensing liquid chamber 2, the display channel 3, and the buffer chamber 4 to avoid obstruction of the flow of the indicator liquid 6 when it moves in a region of large curvature change, thereby improving the responsiveness of the indicator liquid 6 to changes in intraocular pressure. It is understood that the specific value of the preset second curvature can be selected by those skilled in the art according to actual needs.

[0102] According to embodiments of this disclosure, the planar sensing layer and the support structure are made of the same material, and pressure is applied to the planar sensing layer and the support structure to make them adhere together.

[0103] Figure 3 A flowchart illustrating a method for fabricating a microfluidic intraocular pressure sensor based on a dual-sidewall structure according to an embodiment of the present disclosure is shown.

[0104] like Figure 3 As shown, the fabrication method of the microfluidic intraocular pressure sensor based on the double-sidewall structure includes operations S310 to S350.

[0105] In operation S310, a first mold with the size of a sensing display cavity is prepared on a silicon wafer by photolithography. The sensing display cavity includes a sensing liquid cavity 2, a display channel 3, and a buffer chamber 4.

[0106] In operation S320, a liquid flexible polymer solution is spin-coated onto a first mold and a second mold to obtain a patterned first film and a patternless second film.

[0107] In operation S330, the first and second films are subjected to plasma treatment to bond them together, thus obtaining a planar sensing layer.

[0108] In operation S340, a liquid flexible polymer solution is drop-coated onto the surface of a copper mold with a preset curvature. When the liquid flexible polymer solution is in a semi-solid state, it is bonded to the planar sensing layer to obtain a composite material. The composite material is then pressed to obtain a cavity structure for a microfluidic intraocular pressure sensor based on a double-sidewall structure.

[0109] In operation S350, the indicator liquid 6 is filled into the sensing liquid chamber 2 and the display channel 3 through the injection port, and the injection port is sealed with flexible silicone glue to prevent the indicator liquid 6 from flowing back, thus obtaining a microfluidic intraocular pressure sensor based on a dual-sidewall structure.

[0110] According to embodiments of this disclosure, the buffer chamber 4 can be connected to the outside world in order to balance the pressure changes caused by changes in the volume of the sensing liquid chamber.

[0111] Figure 4 The schematic diagram illustrates a step-by-step flowchart of a method for fabricating a microfluidic intraocular pressure sensor based on a dual-sidewall structure according to an embodiment of the present disclosure.

[0112] According to embodiments of this disclosure, a first mold with the size of a sensing display cavity can be obtained on a planar silicon wafer by photolithography.

[0113] According to embodiments of this disclosure, since the heights of the sensing liquid cavity 2 and the buffer chamber 4 can be equal, while the height of the display channel 3 is less than the heights of the sensing liquid cavity 2 and the buffer chamber 4, the sensing liquid cavity 2 and the buffer chamber 4 can be defined on the silicon wafer using photolithography. Then, the display channel 3 can be defined on the silicon wafer using the same process, thus realizing a mold with patterns of different heights. For example, the material used in the photolithography process can be SU-8 2075, SU-8 2050, etc. Embodiments of this disclosure do not limit the specific material type for the photolithography process; those skilled in the art can select according to actual needs.

[0114] like Figure 4 As shown in part (A), the first mold is cut off by a plane perpendicular to the plane where the first mold is located. The cross-sectional schematic diagram of the first mold includes the cavity shape of the sensing display cavity with different cross-sectional diameters made of SU-8 material.

[0115] According to embodiments of this disclosure, such as Figure 4 As shown in section (B), a liquid flexible polymer solution can be spin-coated onto a first mold for molding to obtain a patterned first film.

[0116] According to embodiments of this disclosure, such as Figure 4 As shown in section (C), after obtaining a patterned first thin film, a planar second thin film is fabricated using the same material. The circular size of the second thin film is the same as that of the first thin film, and there are no microstructures on the second thin film. Both the patterned first thin film and the unpatterned second thin film are treated with oxygen plasma, and after being bonded face to face, a cavity structure of the planar sensing layer can be obtained.

[0117] According to embodiments of this disclosure, such as Figure 4As shown in section (D), a polymer solution is drop-coated onto the surface of a copper mold having a preset curvature identical to that of the eyeball. This polymer solution material is the same as that used to fabricate the first and second films. When the polymer solution transitions from a liquid to a semi-solid state, the cavity structure of the planar sensing layer is directly bonded to the surface of the copper mold containing the semi-solid polymer and pressed down to ensure a tight bond between the cavity structure of the planar sensing layer and the semi-solid polymer. This results in a three-dimensional cavity structure of a microfluidic intraocular pressure sensor with a preset curvature and a dual-sidewall structure.

[0118] According to embodiments of this disclosure, such as Figure 4 As shown in section (E), the indicator liquid 6 is dropped at the injection port, and the indicator liquid 6 fills the sensing liquid cavity 2 and the display channel 3 by capillary force. Finally, the injection port is sealed with flexible silicone glue to prevent the dyeing liquid from flowing back.

[0119] According to the embodiments of this disclosure, when a cavity structure of a microfluidic intraocular pressure sensor based on a double-sidewall structure is obtained, an opening can be made at one of the closed ends of the sensing fluid cavity 2 using a punch as an injection port. After the indicator liquid 6 is injected, the injection port can be closed.

[0120] The flexible polymer solution according to the embodiments of this disclosure may include one of the following: polydimethylsiloxane, flexible silicone hydrogel, polydimethylsiloxane-modified polymer, or flexible silicone hydrogel-modified polymer. The embodiments of this disclosure do not limit the specific material type of the flexible polymer solution, and those skilled in the art can select according to actual needs.

[0121] According to embodiments of this disclosure, the process for fabricating a cavity structure of a microfluidic intraocular pressure sensor based on a double-sidewall structure on a planar silicon wafer using photolithography is relatively simple in practical fabrication, and the success rate of fabricating the patterned first thin film is high. Because a predetermined number of double-sidewall structures 5 are provided at the original location of the sensing fluid cavity on the patterned first thin film, the double-sidewall structures 5 can support the cavity during the face-to-face bonding process of the first and second thin films, preventing the cavity walls of the sensing fluid cavity from adhering, further improving the success rate of fabricating the cavity structure of the microfluidic intraocular pressure sensor based on the double-sidewall structure.

[0122] Figure 5 A schematic diagram illustrating the relationship between gas-liquid interface displacement and pressure according to an embodiment of the present disclosure is shown.

[0123] like Figure 5 As shown, the pressure sensed by the microfluidic intraocular pressure sensor based on the double-sided wall structure is linearly proportional to the displacement of the gas-liquid interface 7 in the display channel of the microfluidic intraocular pressure sensor based on the double-sided wall structure.

[0124] According to embodiments of this disclosure, Figure 5 In the figure, x represents the pressure sensed by the microfluidic intraocular pressure sensor based on the double-sided wall structure; y represents the displacement of the gas-liquid interface 7 in the display channel 3 of the microfluidic intraocular pressure sensor based on the double-sided wall structure.

[0125] According to embodiments of this disclosure, Figure 5 The constant value of 659.582 is the slope coefficient used to calculate the pressure sensed by the microfluidic tonometer based on the double-sided wall structure and the displacement of the gas-liquid interface 7 in the display channel 3 of the microfluidic tonometer based on the double-sided wall structure. This slope coefficient characterizes the sensitivity of the microfluidic tonometer based on the double-sided wall structure.

[0126] According to embodiments of this disclosure, Figure 5 The constant value 6318 corresponds to the initial displacement of the microfluidic intraocular pressure sensor based on the double-sided wall structure when it senses a preset pressure. In the specific embodiment corresponding to this value, the preset pressure is approximately 10 mmHg. This constant value can be changed according to actual needs. Applying this constant to the microfluidic intraocular pressure sensor based on the double-sided wall structure ensures that the initial position of the gas-liquid interface 7 is within the display channel 3 when the sensor actually measures intraocular pressure, preventing errors in readings.

[0127] According to embodiments of this disclosure, Figure 5 Chinese R 2 The linearity between the pressure x sensed by the microfluidic tonometer based on the double-sided wall structure and the displacement y of the gas-liquid interface 7 in the display channel 3 of the microfluidic tonometer based on the double-sided wall structure is 0.999, based on actual measurement data. 2 The approximation of 1 indicates that the displacement of the gas-liquid interface 7 in the display channel 3 of the microfluidic intraocular pressure sensor based on the double-sided wall structure can intuitively and accurately reflect the pressure sensed by the microfluidic intraocular pressure sensor based on the double-sided wall structure, and the sensor has good sensing performance.

[0128] According to the embodiments of this disclosure, it can be seen from the above technical solutions that the microfluidic intraocular pressure sensor based on a double-sidewall structure and its preparation method provided by the present invention have at least one or a part of the following beneficial effects:

[0129] (1) The microfluidic intraocular pressure sensor based on the double-sided wall structure can be directly worn on the patient's eyes. It can directly monitor changes in intraocular pressure by detecting the displacement of the gas-liquid interface 7 in the display channel 3. It has the characteristics of being non-invasive, easy to operate, and capable of continuous measurement.

[0130] (2) The sensing fluid cavity of the microfluidic intraocular pressure sensor based on the double-side-wall structure is designed with double side walls, which can effectively improve the success rate of sensor fabrication and optimize the sensor's sensing performance.

[0131] (3) The microfluidic intraocular pressure sensor based on a double-sided wall structure and its preparation method proposed in this invention are prepared by processes such as mold making, which are simple and low in cost.

[0132] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0133] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A microfluidic intraocular pressure sensor based on a dual-sidewall structure, comprising: A corneal contact lens used to transmit changes in intraocular pressure generated by the target eye; The corneal contact lens includes: a planar sensing layer and a support structure located between the planar sensing layer and the target eyeball; The planar sensing layer contains a sensing and display cavity, which is spirally distributed around the center of the planar sensing layer to sense and indicate changes in intraocular pressure; and The support structure is used to maintain the corneal contact lens at a preset first curvature; The sensing and display cavity includes: a sensing liquid cavity, a display channel, and a buffer chamber; The sensing fluid cavity is located on the outer ring of the planar sensing layer away from the center, closed at one end and connected to the display channel at the other end. A preset number of double-sided wall structures are provided inside the sensing fluid cavity. The sensing fluid cavity is filled with indicator fluid to change the volume of the sensing fluid cavity in response to changes in intraocular pressure. A preset number of double-sided wall structures are provided inside the sensing fluid cavity. The spacing between adjacent double-sided wall structures is equal. Each double-sided wall structure includes two supporting walls. The distance between the two supporting walls and the distance between each supporting wall and the cavity wall of its adjacent sensing fluid cavity are equal. The two supporting walls included in each double-sided wall structure are arc-shaped walls with the same curvature as the sensing fluid cavity. Each double-sided wall structure divides the cavity of the sensing fluid cavity into three parallel sub-cavities. The three parallel sub-cavities are connected at the interval between the double-sided wall structure in which it is located and its adjacent double-sided wall structures. One end of the display channel is connected to the sensing fluid chamber, and the other end is connected to the buffer chamber, for displaying the displacement of the indicator fluid in order to display the change in intraocular pressure; One end of the buffer chamber is connected to the display channel, and the other end is closed, which is used to balance the air pressure change caused by the change in the volume of the sensing liquid chamber.

2. The microfluidic intraocular pressure sensor as described in claim 1, wherein, The cross-section of the sensing fluid cavity is a first rectangle.

3. The microfluidic intraocular pressure sensor as described in claim 1, wherein, The sensing fluid chamber is filled with the indicator fluid; as well as The sensing fluid chamber changes volume in response to the change in intraocular pressure, discharging or recovering the indicator fluid.

4. The microfluidic intraocular pressure sensor as described in claim 2, wherein, The display channel has a cross-section of a second rectangle, the area of ​​which is 1 / 10 of the area of ​​the first rectangle.

5. The microfluidic intraocular pressure sensor as described in claim 1, wherein, The planar sensing layer includes a first thin film and a second thin film; The side of the first film that contacts the second film includes a patterned groove; The second film is a patternless smooth film; and The first film and the second film are bonded together after plasma treatment; The patterned groove, which is sealed after being fitted, constitutes the sensing display cavity.

6. The microfluidic intraocular pressure sensor as described in claim 1, wherein, The planar sensing layer and the supporting structure are made of the same material. By applying pressure to the planar sensing layer and the supporting structure, the planar sensing layer and the supporting structure are made to fit together.

7. The microfluidic intraocular pressure sensor as described in claim 1, further comprising: A bend with a preset second curvature is provided at the connection between the sensing liquid cavity and the display channel; as well as A bend with a preset second curvature is provided at the connection between the display channel and the buffer chamber.

8. The microfluidic intraocular pressure sensor as described in claim 7, further comprising: The sensing display cavity is disposed within the internal region of the planar sensing layer, which is defined by an outer ring and an inner ring. The outer ring is a curved ring with a distance of 2 mm from the edge of the planar sensing layer, and the inner ring is a curved ring with a distance of 5 mm from the center. The radius of curvature of the support structure is the same as the radius of curvature of the outer concave side of the corneal contact lens.

9. A method for fabricating a microfluidic intraocular pressure sensor based on a dual-sidewall structure as described in any one of claims 1 to 8, comprising: A first mold with the size of a sensing display cavity is prepared on a silicon wafer by photolithography. The sensing display cavity includes a sensing liquid cavity, a display channel, and a buffer chamber. A liquid flexible polymer solution is spin-coated onto a second mold and a first mold to obtain a patternless second film and a patterned first film. The first and second films are subjected to plasma treatment to bond them together, resulting in a cavity structure of the planar sensing layer. The liquid flexible polymer solution is drop-coated onto the surface of a copper mold with a preset curvature. When the liquid flexible polymer solution is in a semi-solid state, it is bonded to the cavity structure of the planar sensing layer to obtain a composite material. The composite material is then pressed to obtain the cavity structure of the microfluidic intraocular pressure sensor based on the double-sidewall structure. as well as The indicator fluid is filled into the sensing fluid chamber and the display channel through the injection port, and the injection port is sealed with flexible silicone adhesive to prevent the indicator fluid from flowing back, thus obtaining the microfluidic intraocular pressure sensor based on the double-sidewall structure.

10. The preparation method according to claim 9, wherein the flexible polymer solution comprises: One of the following: polydimethylsiloxane, flexible silicone hydrogel, polydimethylsiloxane-modified polymer, or flexible silicone hydrogel-modified polymer.

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