A triple antigen test card

Abstract

A triple antigen test card comprises a shell and three independent liquid paths arranged in the shell, each of the liquid paths is provided with a sample adding port in communication with the outside, an observation window for observing a reading area, a buffer solution adding port and a subsequent liquid path in communication with a chromatographic medium; each of the liquid paths comprises a quantitative cavity in communication with the sample adding port, the top of the quantitative cavity is provided with an independent vent hole covered with a hydrophobic microporous membrane, a threshold trigger valve is arranged between the quantitative cavity and the subsequent liquid path, and the buffer solution adding port is only in communication with the liquid path after the threshold trigger valve, wherein the threshold trigger valve is opened when the quantitative cavity is in a full state or reaches a set volume; the threshold trigger valve remains closed when the quantitative cavity is not in the full state or does not reach the set volume, and the subsequent liquid path comprises a post-valve flow limiting channel in communication with the threshold trigger valve to stabilize the liquid supply to the chromatographic medium.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, and in particular to a triple antigen detection card. Background Technology

[0002] Lateral Flow Immunoassay (LFI) test strips are widely used for rapid screening of multiple targets due to their ease of operation and fast detection speed. Existing multi-strip test strips typically have multiple independent liquid channels within the same housing. After the sample solution is added through the sample dispensing port, the liquid enters the chromatography membrane under capillary force and is drawn by the absorbent pad to complete the colorimetric reading.

[0003] Most existing multi-channel test cards employ a straight-through liquid path consisting of a sample loading port, a liquid delivery channel, a chromatography membrane, and an absorbent pad. The membrane strips are arranged side-by-side, with observation windows corresponding to each strip. Vents are often present on the casing for venting. Some products include an overflow trough in the sample loading area to collect excess sample, and the membrane leading edge utilizes necking, geometric abrupt changes, or microporous membranes to achieve hysteresis and flow restriction. However, these structures have shortcomings in practical use. When the dropping speed or landing point deviates, the liquid path may become wetted before the target volume is formed, leading to premature sample injection. If the venting location or structure is inappropriate, air bubbles may become trapped, causing a "false fullness." If the overflow trough is connected to the main liquid path, excess sample may enter the main channel, compromising measurement accuracy. At the moment of liquid release, a surge and backflow can easily form in the large cross-section in front of the membrane, resulting in inconsistent initial volumes and start-up times across multiple liquid paths.

[0004] Therefore, the existing triple antigen test card has the problem of uneven sample addition, which avoids false negative results caused by insufficient samples and significantly improves the accuracy of testing and the tolerance of operation. Utility Model Content

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, one objective of this invention is to provide a triple antigen detection card, comprising a housing and three independent liquid channels disposed within the housing. Each liquid channel has a sample dispensing port communicating with the outside, an observation window for observing the reading area, a buffer injection port, and a subsequent liquid channel communicating with the chromatography medium. Each liquid channel includes a quantitative chamber communicating with the sample dispensing port. The top of the quantitative chamber has an independent vent hole covered with a hydrophobic microporous membrane. A threshold trigger valve is disposed between the quantitative chamber and the subsequent liquid channel. The buffer injection port communicates only with the liquid channel after the threshold trigger valve. The threshold trigger valve opens when the quantitative chamber is full or reaches a set volume; it remains closed when the quantitative chamber is not full or has not reached the set volume. The subsequent liquid channel includes a post-valve flow-limiting channel communicating with the threshold trigger valve to stably supply liquid to the chromatography medium.

[0006] In one possible implementation, the pore size of the independent vent is 0.3 to 0.6 mm, and the pore size of the hydrophobic microporous membrane is 0.1 to 0.45 μm.

[0007] In one possible implementation, the effective volume of the metering cavity is 60–100 μL, preferably 80 μL.

[0008] In one possible implementation, the threshold trigger valve includes an inlet microgroove communicating with the metering chamber and a sudden expansion section connected thereto. The width w1 of the inlet microgroove is 0.20 to 0.30 mm, the width w2 of the sudden expansion section is 0.8 to 1.0 mm, and the valve length L is 0.6 to 1.5 mm, and satisfies w2 / w1≥3.

[0009] In one possible implementation, the inner wall of the threshold trigger valve is a hydrophobic surface with a static water contact angle ≥110°.

[0010] In one possible implementation, the threshold trigger valve has an opening critical capillary pressure of 50–120 Pa, which is matched with the liquid column pressure in the metering chamber.

[0011] In one possible implementation, a guide structure is provided at the downstream end of the threshold trigger valve, an annular step is provided at the first section after the valve, and a microporous rectifier with an aperture of 0.22 to 0.45 μm is provided downstream of it.

[0012] In one possible implementation, the cross-sectional dimensions of the downstream flow restriction channel are 0.10–0.25 mm in height, 0.50–1.20 mm in width, and 4–6 mm in length.

[0013] In one possible implementation, the buffer injection port has a built-in throttling component, which is a microporous membrane, and the buffer injection port is only connected to the downstream liquid path of the valve.

[0014] In one possible implementation, a slit with a width of 0.3 to 0.6 mm is provided between the three liquid channels, and each liquid channel corresponds to an independent absorbent pad.

[0015] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Based on the above technical solution, the triple antigen detection card of this invention achieves volumetric control of the sample liquid by setting up a quantitative chamber with an independent vent and a hydrophobic microporous membrane in each liquid path. During sample addition, air can be discharged through the vent, allowing the liquid to smoothly enter the quantitative chamber. Only when the sample liquid fills the quantitative chamber and generates sufficient liquid column pressure will this pressure overcome the opening threshold of the threshold trigger valve, causing the valve to open and the sample to enter the subsequent liquid path and supply the chromatography medium. If the sample does not fill the quantitative chamber, the liquid column pressure is insufficient to open the threshold trigger valve, and the liquid cannot enter the downstream liquid path, thus blocking the detection process. This structure realizes automatic determination and control of sample volume, avoids false negative results caused by insufficient sample, and significantly improves detection accuracy and operational error tolerance. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of the triple antigen detection card provided in an embodiment of the present invention; Figure 2 for Figure 1 A cross-sectional view of the sample inlet of the device shown. Figure 3 for Figure 2 Enlarged view of region A in the middle; Figure 4 for Figure 2 A magnified view of region B in the middle.

[0018] Explanation of reference numerals in the attached figures: 1. Shell; 2. Sample inlet; 3. Observation window; 4. Buffer injection port; 5. Quantitative chamber; 6. Independent vent; 7. Hydrophobic microporous membrane; 8. Threshold trigger valve; 9. Chromatography medium; 10. Inlet microgroove; 11. Sudden expansion section; 12. Guiding structure; 13. Throttling component; 14. Absorbent pad. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0020] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0021] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0022] The embodiments of this utility model are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0023] Figure 1 This is a schematic diagram of the structure of the triple antigen detection card provided in an embodiment of the present invention; Figure 2 for Figure 1 A cross-sectional view of the sample inlet 2 of the device shown; Figure 3 for Figure 2 Enlarged view of region A in the middle; Figure 4 for Figure 2 A magnified view of region B in the middle.

[0024] Please see Figure 1-4 In one possible implementation, a triple antigen detection card includes a housing 1 and three independent liquid paths disposed within the housing 1. Each liquid path has a sample application port 2 communicating with the outside, an observation window 3 for observing the reading area, a buffer injection port 4, and a subsequent liquid path communicating with the chromatography medium 9. Each liquid path includes a quantitative chamber 5 communicating with the sample application port 2. The top of the quantitative chamber 5 has an independent vent 6 covered with a hydrophobic microporous membrane 7. A threshold trigger valve 8 is disposed between the quantitative chamber 5 and the subsequent liquid path. The buffer injection port 4 is only connected to the liquid path after the threshold trigger valve 8. The threshold trigger valve 8 is opened when the quantitative chamber 5 is full or reaches a set volume; the threshold trigger valve 8 remains closed when the quantitative chamber 5 is not full or has not reached the set volume. The subsequent liquid path includes a post-valve flow-limiting channel communicating with the threshold trigger valve 8 to stably supply liquid to the chromatography medium 9.

[0025] Specifically, the aforementioned detection card improves sample control and signal stability during the detection process through optimized combination of liquid path structures. After the sample is introduced into each liquid path through the sample inlet 2, the liquid first fills the quantitative chamber 5. The vent at the top of the chamber, in conjunction with the hydrophobic microporous membrane 7, allows gas to escape smoothly while preventing liquid leakage, thus ensuring smooth liquid injection. When the quantitative chamber 5 is completely filled or the liquid volume reaches the set value, the pressure generated by the liquid column inside reaches the threshold trigger valve 8, which is automatically activated, allowing the sample to enter the subsequent liquid path. This mechanism ensures that detection is only initiated when a sufficient amount of sample is reached, effectively preventing false judgments caused by low sample volume. The flow-limiting channel set after the trigger valve regulates the liquid flow rate, ensuring a stable flow rate when flowing through the chromatography medium 9 region, guaranteeing the uniformity of the chromatography reaction and the reliability of the detection results. The independent setting of the buffer injection port 4 avoids buffer interference in the quantitative process, intervening only after the sample flows, which helps to promote sample flow and complete subsequent reactions.

[0026] Through the above structure, the test card achieves liquid control while maintaining a compact design, which not only improves operational convenience and detection accuracy but also enhances the system's tolerance to abnormal sample volumes. The independent configuration of multiple liquid paths allows for the parallel detection of multiple antigens, improving diagnostic efficiency. The coordination mechanism between the quantitative chamber 5 and the trigger valve enables automatic sample volume determination, avoiding manual intervention and improving the standardization of the detection process.

[0027] In one possible implementation, the pore size of the independent vent 6 is 0.3 to 0.6 mm, and the pore size of the hydrophobic microporous membrane 7 is 0.1 to 0.45 μm.

[0028] Specifically, the vent diameter is set between 0.3 and 0.6 mm, which facilitates the effective discharge of gas from the cavity during liquid injection, preventing liquid flow interruption due to gas resistance, and also preventing liquid from overflowing to the vent. By covering the vent with a hydrophobic microporous membrane 7 with a pore size of 0.1–0.45 μm, the system's liquid-gas separation capability can be further enhanced. This pore size range effectively prevents liquid permeation while allowing gas to pass through smoothly, thus ensuring that the metering chamber 5 remains in a state of gas pressure balance during liquid injection, preventing liquid column breakage or premature valve triggering.

[0029] The aforementioned structure enhances the stability of the sample injection process, preventing microbubbles or liquid residue from affecting threshold triggering, thus making the entire flow control process more stable and controllable. By ensuring consistent sample volume in each test, it improves the repeatability and accuracy of test results. The membrane structure is not directly exposed to the sample liquid, effectively reducing the risk of clogging and extending the lifespan of the test card.

[0030] In one possible implementation, the effective volume of the metering chamber 5 is 60–100 μL, preferably 80 μL.

[0031] Specifically, the above structure ensures that the sample volume received by each liquid path maintains a certain operational tolerance while meeting detection sensitivity requirements. Specifically, 60 μL is the lower limit volume to guarantee basic reaction requirements, 100 μL is the maximum safe volume the system can hold, and 80 μL represents a balance between liquid filling efficiency, reaction adequacy, and system stability. By setting upper and lower limits for the effective volume, sample overflow due to excessive liquid injection can be effectively prevented, and the problem of inaccurate threshold triggering due to insufficient sample can also be avoided, thus ensuring consistency and reliability in each detection process.

[0032] Furthermore, the volume setting of the quantitative chamber 5 directly affects the opening timing of the threshold trigger valve 8. By matching the set liquid column pressure with the threshold trigger condition, it automatically triggers when the liquid volume reaches the predetermined value, ensuring that subsequent reactions proceed according to the predetermined rhythm. Precise control of the sample volume can also reduce signal deviation during chromatography, improving the clarity and readability of the colored area on the test strip. In addition, the fixed volume design simplifies the user operation process, enabling non-professionals to obtain reproducible results in practical applications, making it particularly suitable for rapid testing scenarios such as primary healthcare and home self-testing.

[0033] Please see Figure 2 In one possible implementation, the threshold trigger valve 8 includes an inlet microgroove 10 connected to the metering chamber 5 and a sudden expansion section 11 connected thereto. The width w1 of the inlet microgroove 10 is 0.20 to 0.30 mm, the width w2 of the sudden expansion section 11 is 0.8 to 1.0 mm, the valve length L is 0.6 to 1.5 mm, and w2 / w1≥3 is satisfied.

[0034] Specifically, the flow of liquid within the capillary structure is restricted by capillary pressure. When sample liquid flows from the metering chamber 5 into the inlet microchannel 10, it is temporarily blocked by a large capillary force due to the narrow channel, preventing it from entering the subsequent liquid path. Only when the liquid accumulates in the metering chamber 5 to a certain column height and the internal static pressure exceeds the capillary resistance will flow be triggered, allowing it to cross the expansion section 11 and enter the subsequent system.

[0035] Therefore, the sudden expansion section 11 rapidly expands the channel cross-section through a geometric abrupt change, causing a change in the liquid contact angle and a sudden drop in capillary force, thus forming a critical potential barrier in fluid dynamics. Once the inlet liquid overcomes this barrier and fills the sudden expansion section 11, the entire channel transitions to a low-resistance flow state, forming a continuous channel, thereby allowing the liquid to flow stably. The function of the sudden expansion section 11 is to reinforce this capillary pressure abrupt change range, construct a clear "start threshold," prevent erroneous flow when the sample volume is insufficient, and ensure that the reaction process is only initiated when the liquid column pressure is sufficient.

[0036] The channel length L controls the residence path of the liquid inside the valve. While maintaining a compact structure, it adjusts the overall capillary stability zone length, which helps improve the dynamic stability and interface retention during liquid flow. Furthermore, the width ratio setting of w2 / w1≥3 ensures a sufficiently significant capillary pressure drop, guaranteeing a clear capillary force change effect that is less susceptible to manufacturing tolerances, liquid viscosity, or environmental changes, thus improving the consistency and repeatability of the trigger valve.

[0037] In one possible implementation, the inner wall of the threshold trigger valve 8 is a hydrophobic surface, and its static water contact angle is not less than 110°.

[0038] The aforementioned structure enhances the threshold control capability for liquid flow by regulating the surface properties of the valve body's inner wall. Specifically, the hydrophobic surface has a high contact angle, which significantly increases the interfacial energy between the liquid and the channel wall, making it more difficult for the liquid to wet the channel surface, thereby increasing the capillary pressure required to pass through this area. When the liquid enters the threshold trigger valve 8 from the metering chamber 5, it must overcome the repulsive effect generated by the hydrophobic surface to complete the interface expansion and move forward. Therefore, the stronger the hydrophobicity, the higher the required liquid column pressure, and the more obvious the threshold triggering effect.

[0039] When the contact angle is not less than 110°, the liquid exhibits a "spherical aggregation" state on the surface, making it difficult to diffuse and flow across the wall, thus increasing the initial resistance at the valve. This structure allows the threshold trigger valve 8 to not only rely on the capillary pressure difference generated by the abrupt change in channel geometry but also further incorporate the surface energy limiting factor, forming a dual control mechanism. Even under conditions of fluctuating ambient temperature and humidity or changes in sample surface tension, relatively constant triggering conditions can be maintained, improving system stability.

[0040] The valve body surface treated with hydrophobic coating can be achieved through chemical coating (such as fluorosilane), plasma treatment, or hydrophobic polymer coating. The treated surface has low energy, making it less prone to adsorbing moisture or impurities. This helps avoid problems such as false triggering or valve lag caused by minute contaminants or liquid residue, while also improving the self-cleaning performance of the flow channel and extending the reliable service life of the device.

[0041] It is worth noting that the hydrophobicity parameter can be fine-tuned according to different liquid properties. For example, when used for biological samples with low surface tension, the contact angle can be further increased to over 120° to enhance the liquid-blocking effect. The hydrophobic effect can also be physically enhanced through micro / nano-structured surface textures (such as lotus leaf-like structures), thereby improving control capabilities without altering the material itself. Hydrophobic regions can also be locally deployed, concentrated only in critical threshold segments, thus balancing triggering accuracy with manufacturing cost control.

[0042] In one possible implementation, the threshold capillary pressure for opening the threshold trigger valve 8 is set between 50 and 120 Pa, a pressure range that matches the static pressure generated by the liquid column in the metering chamber 5 under normal filling conditions. For example, in a preferred embodiment, when the effective volume of the metering chamber 5 is 80 μL, the liquid column pressure corresponding to its vertical height is approximately 70–90 Pa, which is just within the critical opening range of the trigger valve. This structure ensures that only when the sample liquid actually reaches the predetermined volume can a pressure sufficient to overcome the threshold capillary pressure be generated, thereby triggering the liquid to flow into subsequent liquid paths.

[0043] The capillary pressure of the trigger valve is determined by the width w1 of its microgroove, the width w2 of its expansion section 11, the valve length L, and the contact angle of its inner wall. In this embodiment, by setting the width of the inlet microgroove 10 to 0.25 mm and the width of the expansion section 11 to 0.9 mm (satisfying w2 / w1≥3), and by performing hydrophobic treatment on the inner surface of the valve (contact angle≥110°), the critical pressure can be stably controlled within the above range. This parameter configuration not only demonstrates good repeatability in experiments (batch-to-batch fluctuation <±5 Pa), but also adapts to changes in ambient temperature and liquid viscosity, maintaining reliable valve triggering.

[0044] The aforementioned structure establishes a stable balance between the static pressure in the quantitative chamber 5 and the capillary resistance of the threshold trigger valve 8, enabling automated, passively controlled quantitative liquid release. This mechanism does not rely on additional sensors or pressurization devices, possesses a natural cutoff function when the sample volume is insufficient, and can stably release when the sample volume is sufficient, thus improving the overall device's fault tolerance and detection reliability.

[0045] Please see Figure 2 , 4 In one possible implementation, a guide structure 12 is provided at the downstream end of the threshold trigger valve 8, an annular step is provided at the first section after the valve, and a microporous rectifier with a pore size of 0.22 to 0.45 μm is configured downstream of it.

[0046] During the process of liquid flowing from the threshold trigger valve 8 into the downstream liquid path, without a guiding structure, the liquid interface is easily deformed, air bubbles are entrained, or there is a sudden change in contact angle due to unstable liquid kinetic energy, which in turn affects the stability of the liquid supply in the flow-limiting channel. This embodiment provides a guiding structure 12 at the valve outlet end, which allows the liquid to smoothly expand along a predetermined path when it enters the flow channel front in the initial stage, reducing the probability of interface instability. The guiding structure 12 effectively mitigates the risk of backflow caused by the liquid impacting the front wall through geometric guidance, providing a smooth transition for the liquid in the flow-limiting section.

[0047] Specifically, an annular step downstream of the guide section forms a local liquid collection cavity to stabilize the liquid flow rate and reduce lateral liquid drift. The step's height and width are designed proportionally to ensure continuous liquid flow while simultaneously providing physical flow restriction and stabilizing the interface transition; it is a crucial buffer unit connecting the trigger valve and the rectifier plate. The microporous rectifier plate, located immediately downstream of the step, has a pore size controlled between 0.22 and 0.45 μm, effectively filtering out fine particles or bubbles and stabilizing the liquid interface morphology at the front end. The pore structure of the rectifier plate allows for surface flow control, preventing directional drift, sudden velocity changes, or intermittent flow before the liquid enters the chromatography region, thus significantly improving the consistency and continuity of the liquid supply.

[0048] The above structure not only improves the control accuracy of the liquid in the transition region, but also reduces the system's sensitivity to external interference factors such as attitude and gravity direction, making the detection card suitable for use in various scenarios such as multi-angle placement and vibration transportation.

[0049] In one possible implementation, the cross-sectional dimensions of the downstream flow restriction channel are 0.10–0.25 mm in height, 0.50–1.20 mm in width, and 4–6 mm in length.

[0050] Following the threshold trigger valve 8, the channel structure further controls the flow rate and volume of liquid entering the chromatography medium 9. Specifically, by precisely defining the channel geometry within a microscale range, capillary pressure-driven fluid control can be achieved, ensuring that liquid is supplied to the chromatography region in a constant, slow, and repeatable manner, avoiding problems such as sample overflow, incomplete chromatography, or signal drift.

[0051] The height of 0.10–0.25 mm ensures the channel is within the capillary control range, preventing flow velocity fluctuations due to gravity or inertia under capillary force. The width of 0.50–1.20 mm provides sufficient cross-sectional area to suppress interfacial fluctuations while maintaining a certain flux, achieving stable interfacial propagation. The length of 4–6 mm acts as a buffer, allowing for a smooth velocity transition in the flow-limiting channel after the liquid's momentary release through the trigger valve, effectively delaying the initial impact and preventing an "overshoot" effect on the chromatography membrane.

[0052] It is worth noting that the geometric constraint design of the flow-limiting channel can also be coordinated with the capillary liquid absorption capacity of the subsequent chromatography strips to form an overall liquid flow impedance matching system.

[0053] Please see Figure 2 , 3 In one possible implementation, the buffer injection port 4 has a built-in throttling member 13, which is a microporous membrane, and the buffer injection port 4 is only connected to the liquid path after the threshold trigger valve 8.

[0054] The above structure addresses the issue of buffer solution accidentally flowing into the chromatography region when sample quantification conditions are not met, thereby preventing background interference or false color development. Specifically, by setting a throttling component 13 within the buffer inlet 4 and using a microporous membrane with limited permeability as this component, passive control of the buffer solution inflow rate and initiation timing is achieved, forming an auxiliary flow-limiting mechanism.

[0055] The permeability of the microporous membrane allows the buffer solution to enter the liquid path at a controlled rate after external addition. Its inherent filtration and flow stabilization functions help suppress potential instantaneous pressure surges during the injection process. The throttling component 13 is positioned after the threshold trigger valve 8, meaning the buffer solution can only enter the triggered liquid path and cannot flow into the chromatography medium 9 through channels that do not meet the sample volume requirements. This ensures that the timing of buffer solution intervention is strictly matched to the sample detection process. This flow path selectivity effectively improves the system's anti-interference capability and enhances the controllability of the reaction sequence.

[0056] Furthermore, even if the user injects buffer solution in advance during operation, it will not adversely affect the detection process. Simultaneously, this structure can be performed in parallel with conventional sample loading operations, simplifying the usage process and improving the end-user experience. The microporous membrane, as a throttling component 13, also possesses good chemical compatibility and dimensional controllability, facilitating standardized integration during mass production.

[0057] In one possible implementation, a slit with a width of 0.3 to 0.6 mm is provided between the three liquid channels, and each liquid channel corresponds to an independent absorbent pad 14.

[0058] The aforementioned structure, by incorporating physical isolation slits between the three liquid channels, effectively prevents lateral penetration or capillary cross-flow of liquids in different channels during use, thereby avoiding mutual interference between detection signals. The slit width is controlled within the range of 0.3–0.6 mm, based on the balance between the surface tension behavior of the liquid and the capillary traction force between the microscopic channels, ensuring that the liquid interfaces of each channel remain independent and do not contact each other under normal detection conditions.

[0059] Specifically, the independent absorbent pads 14 at the end of the liquid path further enable directional driving of the liquid flow and collection of residual liquid. Each absorbent pad 14 is independently arranged and connected to the corresponding chromatography strip, ensuring that the liquid supply, reaction, and end liquid traction processes of each liquid path do not interfere with each other. The absorbent pads 14 continuously pull the liquid through their own capillary drive, which helps the sample to pass completely through the detection line, while removing unreacted reagent residues, reducing background noise, and improving the clarity of the detection window.

[0060] This structure effectively improves the independence of liquid paths and system stability in multi-channel antigen detection card applications. On the one hand, the physically isolated slit design prevents capillary crossflow or liquid cross-permeation between adjacent liquid paths, ensuring that the detection processes of each channel do not interfere with each other, thereby achieving signal independence and response consistency when multiple indicators are detected simultaneously. On the other hand, even under conditions of slight device tilt or unstable operating posture, the isolation structure can still maintain stable liquid flow along its respective path, improving the robustness of the device in actual use environments. In addition, the slit structure is easy to implement through processes such as injection molding or in-mold inserts, and has high compatibility with the integrated design of the detection card housing 1, which helps to standardize production molds and control dimensional consistency in mass production processes, enhancing the feasibility of this solution.

[0061] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0062] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

[0063] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0064] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A triple antigen detection card, comprising a housing and three independent liquid channels disposed within the housing, each liquid channel having a sample application port communicating with the outside, an observation window for observing the reading area, a buffer injection port, and a subsequent liquid channel communicating with the chromatography medium; characterized in that: Each of the liquid paths includes a quantitative chamber connected to the sample dispensing port. The top of the quantitative chamber is provided with an independent vent hole covered with a hydrophobic microporous membrane. A threshold trigger valve is provided between the quantitative chamber and the subsequent liquid path. The buffer injection port is only connected to the liquid path after the threshold trigger valve. The threshold trigger valve opens when the quantitative chamber is full or reaches a set volume; the threshold trigger valve remains closed when the quantitative chamber is not full or has not reached the set volume. The subsequent liquid path includes a post-valve flow-limiting channel connected to the threshold trigger valve to stably supply liquid to the chromatography medium.

2. The triple antigen detection card according to claim 1, characterized in that, The diameter of the independent vent is 0.3 to 0.6 mm, and the diameter of the hydrophobic microporous membrane is 0.1 to 0.45 μm.

3. The triple antigen detection card according to claim 1 or 2, characterized in that, The effective volume of the metering cavity is 60–100 μL.

4. The triple antigen detection card according to claim 1, characterized in that, The threshold trigger valve includes an inlet microgroove connected to the metering chamber and a sudden expansion section connected thereto. The width w1 of the inlet microgroove is 0.20 to 0.30 mm, the width w2 of the sudden expansion section is 0.8 to 1.0 mm, and the valve length L is 0.6 to 1.5 mm, and satisfies w2 / w1≥3.

5. The triple antigen detection card according to claim 4, characterized in that, The inner wall of the threshold trigger valve is a hydrophobic surface and the static water contact angle is ≥110°.

6. The triple antigen detection card according to claim 5, characterized in that, The threshold trigger valve has an opening critical capillary pressure of 50–120 Pa, which is matched with the liquid column pressure in the metering chamber.

7. The triple antigen detection card according to claim 6, characterized in that, The downstream end of the threshold trigger valve is provided with a guide structure, an annular step is provided at the first section after the valve, and a microporous rectifier with a pore size of 0.22 to 0.45 μm is provided downstream of it.

8. The triple antigen detection card according to claim 7, characterized in that, The cross-sectional dimensions of the downstream flow restriction channel are: height 0.10–0.25 mm, width 0.50–1.20 mm, and length 4–6 mm.

9. The triple antigen detection card according to claim 1, characterized in that, The buffer injection port has a built-in throttling component, which is a microporous membrane, and the buffer injection port is only connected to the downstream liquid path of the valve.

10. The triple antigen detection card according to claim 1, characterized in that, A slit with a width of 0.3 to 0.6 mm is set between the three liquid channels, and each liquid channel corresponds to an independent absorbent pad.

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