3D folded paper-based microfluidic multi-channel detection device and method

Abstract

The application discloses a 3D folded paper-based microfluidic multi-channel detection device and method. The device comprises a sample pretreatment distribution part, a longitudinal filtrate part arranged at one end of the sample pretreatment distribution part, and a multi-index color development part arranged at the other end of the longitudinal filtrate part. The sample pretreatment distribution part comprises a sample injection area and a liquid storage area arranged at the end of a flow channel distributed around the sample injection area. The surface of the flow channel and the surface of the liquid storage area are both solidified with a coagulant. The longitudinal filtrate part comprises a filtrate area, and the surface of the filtrate area is solidified with a coagulant. The multi-index color development part comprises a color development area. The longitudinal filtrate part is folded before the multi-index color development part. In a first folding state, the longitudinal filtrate part is folded forward to coincide with the filtrate area and the liquid storage area. In a second folding state, the multi-index color development part is further folded backward to coincide with the color development area and the filtrate area. The application can achieve the purposes of simple structure, convenient operation, direct processing of mixed sample liquid, uniform color development, and simultaneous multi-index integrated detection.

Description

Technical Field

[0001] This application relates to the field of point-of-care testing technology, specifically to a 3D folded paper-based microfluidic multichannel detection device and method. Background Technology

[0002] In recent years, paper-based microfluidics technology has been widely explored for point-of-care testing due to its advantages such as low cost, portability, no need for external pumps, and disposable nature. However, existing paper-based devices are mostly planar structures with low channel integration, making it difficult to achieve efficient solid-liquid separation and simultaneous detection of multiple liquid parameters. Furthermore, although existing research has attempted to achieve multi-step reaction control through folded structures, these structures have significant limitations:

[0003] (1) One type is folded before use, which is essentially equivalent to a multi-layer adhesive structure and cannot be used to trigger fluid timing control by folding action;

[0004] (2) Another type folds during the reaction, but each layer is a functional reaction zone. It lacks a non-reactive storage zone structure specifically for buffering and homogenizing the sample flow, which results in a lateral velocity gradient when the sample enters the detection zone, and cannot effectively suppress the coffee ring phenomenon of the liquid.

[0005] Therefore, there is an urgent need for a new type of paper-based microfluidic detection platform that is simple in structure, easy to operate, can directly process sample liquids, and can simultaneously detect multiple liquid indicators, so as to truly meet the real-time detection needs of multiple liquid indicators in various industries. Summary of the Invention

[0006] In view of this, the main objective of this application is to provide a 3D folded paper-based microfluidic multichannel detection device and method, so as to achieve the purpose of simple structure, convenient operation, direct processing of sample liquid, uniform color development, and simultaneous integrated detection of multiple indicators.

[0007] In a first aspect, this application provides a 3D folded paper-based microfluidic multichannel detection device. The main body of the detection device includes a first part, a second part disposed at one end of the first part, and a third part disposed at the other end of the second part. The first part is a sample pretreatment and dispensing section, the second part is a longitudinal filtrate section, and the third part is a multi-index colorimetric section.

[0008] The sample pretreatment and distribution unit includes a sample injection area located in the center, multiple flow channels distributed around the sample injection area, a liquid storage area at the end of the flow channel, and a coagulant solidified on the surface of the flow channel and the surface of the liquid storage area.

[0009] The longitudinal filtrate section contains multiple independent filtrate zones arranged in parallel, and the surface of the filtrate zones is solidified with a coagulant.

[0010] The multi-index colorimetric section contains multiple independent and parallel colorimetric zones, each of which is solidified with colorimetric reaction reagents corresponding to multiple liquid indices in the sample solution.

[0011] The 3D folded paper-based microfluidic multichannel detection device undergoes two folding states in sequence during use, with the longitudinal filtrate section folding before the multi-index color development section. In the first folding state, the longitudinal filtrate section has been folded forward until the front of the filtrate area coincides with the front of the liquid storage area in the corresponding position.

[0012] In the second folded state, the multi-index colorimetric section is further folded back to overlap with the back of the colorimetric area and the back of the filtrate area in the corresponding position.

[0013] As described above, the flow channel surface and the liquid storage area surface of the sample pretreatment distribution section are respectively solidified with coagulants, which causes the sample liquid to form aggregated large molecular particles during the flow process in the flow channel and the waiting process of uniformly filling the liquid storage area, thus pretreating the sample liquid and eliminating complex operations such as centrifugation and pipetting. This facilitates the filtration step and truly realizes convenient use in real-time testing scenarios. The longitudinal filtration section adopts an independent filtration area, which, combined with its folded design that overlaps with the liquid storage area, achieves efficient separation of aggregated particles and clear liquid phase in the sample liquid. This significantly reduces the interference of aggregated particles in the sample liquid on the colorimetric reaction, thereby improving the linear correlation between the detection signal and the concentration of liquid index. A dedicated liquid storage area is set at the end of the flow channel, allowing the sample liquid to fully settle and be evenly distributed after the lateral flow ends. After folding, the liquid penetrates into the filtration area and colorimetric area in a purely longitudinal manner, avoiding edge enrichment caused by lateral flow, effectively suppressing the coffee ring phenomenon, and making the color distribution in the colorimetric area uniform. This facilitates stable reading of values ​​by multi-channel quantitative colorimetric reading equipment and improves detection repeatability and resolution. The device is compact and easy to operate, making it suitable for rapid on-site testing scenarios. The functional areas of the first to third parts of the device are physically isolated to prevent cross-contamination and improve testing reliability.

[0014] As an optional embodiment of the first aspect, the longitudinal filtrate section uses Whatman No. 3 filter paper or alternative filter paper with equivalent pore size and capillary properties.

[0015] As described above, during the longitudinal permeation process of the longitudinal filtrate section, the aggregated particles in the sample solution, due to their size being larger than the pores of the filter paper, are deposited at the bottom of the longitudinal filtrate section under the influence of gravity, while the clarified liquid phase flows upward along the fiber network longitudinally through capillary action, achieving efficient solid-liquid separation in the sample solution. This characteristic of the filter paper can effectively trap aggregated particles while retaining a good capillary rise rate of the clarified liquid phase.

[0016] As an optional embodiment of the first aspect, the number of liquid storage zones, the number of filtrate zones, and the number of color development zones are equal.

[0017] As shown above, after the device is folded, the three areas of liquid storage area, filtrate area and color development area are located in the same vertical area and are arranged adjacent to each other in sequence. Therefore, the number of liquid storage area, filtrate area and color development area are equal and they correspond one by one in terms of orientation.

[0018] As an optional embodiment of the first aspect, one end of the flow channel is also connected to the sample inlet of the lateral chromatography device.

[0019] As shown above, one of the flow channels is also connected to the sample inlet of the lateral chromatography device, which fully combines the advantages of the paper-based microstructure of the device and the lateral chromatography device, and has strong scalability. After the sample solution flows to the sample inlet of the lateral chromatography device after the flow channel pretreatment step, the simultaneous detection of protein macromolecules is completed by lateral chromatography of the sample solution, realizing the detection of liquid indicators of small molecules and macromolecules in one go.

[0020] As an optional embodiment of the first aspect, the number of flow channels is not less than the number of liquid storage areas.

[0021] Therefore, in order to achieve the scalability of the device and integrate the detection of other liquid indicators, flow channels should also be reserved for use in other detections, such as immunochromatographic detection.

[0022] As an optional embodiment of the first aspect, when the longitudinal filtrate section and the multi-index color development section are not folded, the sample pretreatment distribution section, the longitudinal filtrate section and the multi-index color development section are arranged adjacent to each other and laid out in a coplanar manner.

[0023] As described above, when the three functional areas are initially folded and in use, they are arranged in an adjacent, flat, and coplanar manner. Crease lines are also set between the first and second parts, and between the second and third parts. This not only facilitates the folding of these three parts, but also greatly simplifies the manufacturing process, reduces costs, and effectively ensures the reliability of testing. At the same time, this layout allows users to precisely control the reaction sequence by simply folding the parts step by step without complicated assembly, avoiding cross-interference, and facilitating portable storage.

[0024] Secondly, this application also provides a method for simultaneous detection of multiple liquid indicators, which uses the 3D folded paper-based microfluidic multichannel detection device described in any of the first aspects to simultaneously detect multiple liquid indicators in a sample solution, comprising:

[0025] The sample solution is added dropwise to the sample injection area of ​​the sample pretreatment distribution section, and the sample solution flows laterally from the injection area to the storage area along the flow channel.

[0026] After the sample liquid in the storage area stops flowing and is evenly distributed, fold the longitudinal filtrate section to fit tightly against the front of the filtrate area and the front of the storage area, so that the sample liquid is filtered into the filtrate area by longitudinal permeation.

[0027] After the filtered sample solution evenly fills the filtrate area, the multi-index colorimetric part is folded back to the back of its colorimetric area and closely adhered to the back of the filtrate area, so that the filtered sample solution enters the front of the colorimetric area in a longitudinal permeation manner and a colorimetric reaction occurs.

[0028] After the colorimetric reaction is fully completed, insert the 3D folded paper-based microfluidic multichannel detection device into the multichannel quantitative colorimetric reading device, and quantitatively output the values ​​of multiple liquid indicators through the accompanying application.

[0029] As described above, the sample solution undergoes surface modification as it flows laterally through the flow channel in the sample pretreatment distribution section, thus pretreating the sample solution to achieve particle aggregation. While continuing particle aggregation in the storage zone of the sample pretreatment distribution section, and waiting for the sample solution to be evenly distributed, the longitudinal filtration section is folded to create uniform longitudinal liquid flow conditions. Utilizing the characteristic that aggregated particles are less likely to flow longitudinally, combined with the filtration zone of the longitudinal filtration section, further filtration of the sample solution is achieved, allowing the clarified liquid phase to flow longitudinally into the filtration zone. Colorimetric detection of liquid indicators is then performed in the color development zone of the multi-index colorimetric section. This device achieves automatic sample pretreatment, supports high-precision multi-index detection, and also enables quantitative detection. Furthermore, it is the first device to achieve simultaneous, real-time detection of multiple liquid indicators under the same environment. This method utilizes a 3D folded paper-based microfluidic multichannel detection device with a folding sequence that alters the sample flow pattern. Specifically, by waiting for the sample liquid to uniformly fill the reservoir and stop flowing before folding, the flow pattern is changed from the existing combination of lateral and longitudinal flow (flowing and seeping simultaneously) to a flow pattern where lateral flow stops before longitudinal flow occurs after the reservoir is established. This reduces the lateral elution effect within the color development zone, suppresses the formation of the coffee ring phenomenon, and ultimately improves color uniformity and detection resolution. Furthermore, this method triggers solid-liquid separation during the two folds, achieving effective separation of the sample liquid and significantly improving detection linearity.

[0030] As an optional embodiment of the second aspect, a coagulant is solidified on the surface of the storage area and the surface of the flow channel. During the process of the sample liquid flowing laterally in the flow channel and the sample liquid uniformly filling the storage area, the coagulant pre-treats the sample liquid, wherein the pre-treatment includes particle agglomeration treatment of the sample liquid.

[0031] As described above, the sample solution is pretreated during its flow in the channel and during the process of uniformly filling the storage area, forming large particles that are easy to settle. This significantly shortens the solid-liquid separation time, improves the clarity of the filtered sample solution, reduces the risk of particles clogging the filter paper pores, and ensures the sensitivity of the subsequent colorimetric reaction.

[0032] As an optional embodiment of the second aspect, the sample solution flows laterally along a flow channel to the injection end of the lateral chromatography device, and the detection line signal and control line signal of the lateral chromatography device are synchronously acquired and quantitatively analyzed by a multi-channel quantitative colorimetric reading device.

[0033] The sample solution, after pretreatment in one of the channels, enters the lateral chromatography device to complete the immunochromatographic detection of protein macromolecules. The lateral chromatography signal is simultaneously acquired and quantified by a multi-channel quantitative colorimetric reading device, realizing the fusion of data from the colorimetric channel and the chromatography channel, and improving the repeatability and accuracy of the immunoassay.

[0034] In summary, this application provides a 3D folded paper-based microfluidic multichannel detection device and method. This device, through a three-stage collaborative design of a sample pretreatment distribution section – a longitudinal filtrate section – and a multi-index colorimetric section, integrates automatic sample filtration, multi-channel distribution, chemical colorimetry, and immunochromatography. It significantly improves the accuracy, uniformity, and linearity of detection, and achieves one-stop, simultaneous, and real-time detection of multiple liquid indicators. It boasts advantages such as ease of operation, low cost, and strong scalability. This method, through the coordinated structure and folding sequence of the device, alters the traditional flow pattern of the sample solution, weakens the lateral elution effect within the colorimetric zone, and suppresses the formation of the coffee ring phenomenon, thereby ultimately improving colorimetric uniformity and detection resolution. The longitudinal filtrate section employs an independent filtrate zone, which, combined with the design of overlapping with the end reservoir after folding, achieves efficient sample separation, significantly reducing the interference of aggregated particles in the sample solution on the colorimetric reaction, thereby improving the linear correlation between the detection signal and the concentration of the liquid indicator. Attached Figure Description

[0035] The various technical features of this application and their relationships will be further explained below with reference to the accompanying drawings. The drawings are exemplary; some technical features are not shown to scale, and some drawings may omit technical features commonly used in the art to which this application pertains that are not essential for understanding and implementing this application, or additionally show technical features that are not essential for understanding and implementing this application. In other words, the combination of various technical features shown in the drawings is not intended to limit this application. Furthermore, throughout this application, the same reference numerals refer to the same things. Specific descriptions of the drawings are as follows:

[0036] Figures 1a-1b This is a structural view of the 3D folded paper-based microfluidic multichannel detection device in this application;

[0037] Figure 2 This is a comparison of the standard curves for creatinine detection between the 3D folded paper-based microfluidic multichannel detection device in this application and existing devices.

[0038] Figure 3 This is a bar chart comparing the H-color values ​​of the 3D folded paper-based microfluidic multichannel detection device in this application with those of existing devices in the color development area;

[0039] Figure 4 This is a flowchart illustrating the method for simultaneous detection of multiple liquid indicators in this application.

[0040] Explanation of reference numerals in the attached figures

[0041] 1-Sample pretreatment and distribution unit, 10-Sample injection area, 11, 12-Storage area, 13-Side chromatography device, 14, 15, 16-Flow channel, 2-Longitudinal filtrate unit, 20, 21-Filtrate area, 3-Multi-index colorimetric unit, 30, 31-Colorimetric area, 4-Multi-channel quantitative colorimetric reading device.

[0042] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0043] The preferred embodiments of this application will now be described in detail with reference to the accompanying drawings, so that the advantages and features of this application can be more easily understood by those skilled in the art, thereby providing a clearer and more definite definition of the scope of protection of this application.

[0044] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0045] It should be noted that in the description herein, the terms "middle," "front," "back," "top," "bottom," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention 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. Therefore, they should not be construed as limitations on this application.

[0046] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," "socketing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection; they can refer to a direct connection, an indirect connection via an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0047] To clearly illustrate the implementation of this application, the structures shown in the accompanying drawings are merely illustrative of preferred embodiments of this application and are not intended to limit the technical solutions of this application. Some details (such as specific dimensions, shapes, or connection methods) may be simplified or omitted, and should not be presumed to be an undue limitation on the scope of protection of this application. For the omitted parts or details that are not precisely represented, those skilled in the art can understand and implement them based on the content of this application and conventional technical means.

[0048] It should be noted that the multi-channel detection device for sample solutions described in this application can be widely applied in various fields such as environmental and water quality monitoring, food safety, industrial process control and chemical engineering, biomanufacturing, scientific research analysis, agricultural and soil extract detection, and rapid on-site detection. It has significant application value for the simultaneous, rapid, and low-cost quantitative analysis of multiple chemical or biological components in complex liquid samples. For example, in the field of environmental and water quality monitoring, multiple liquid indicators such as nitrates, nitrites, and heavy metal ions need to be detected simultaneously in water quality assessment; in food processing, the content of preservatives and oxidants, such as sulfur dioxide, melamine, and glucose, needs to be monitored; in biomanufacturing and scientific research, cell culture often requires real-time tracking of changes in the concentration of metabolites such as glucose, lactic acid, and proteins. It can also be used to detect multiple liquid indicators in whole blood samples. These liquid indicators can include routine blood parameters, biochemical parameters covering blood glucose, blood lipids, serum creatinine, blood urea nitrogen, and electrolytes, and include, but are not limited to, parameters such as protein concentration, lactic acid, glucose, creatinine, uric acid, and albumin.

[0049] The aforementioned liquid indicators are not only found in biological cell culture media, but are also widely distributed in biological manufacturing waste liquids, environmental water bodies, or food extracts. This multi-channel detection device is suitable for the detection of a variety of liquids, and the liquid indicators may include one or more of small molecule organic matter, inorganic ions, proteins, or polysaccharides.

[0050] The technical solutions of this application and how they solve the aforementioned technical problems will be described in detail below with specific embodiments. The specific embodiments described below can be combined with each other to form new embodiments. The same or similar ideas or processes described in one embodiment may not be repeated in other embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0051] [Specific Implementation Examples of a 3D Folded Paper-Based Microfluidic Multichannel Detection Device]

[0052] This 3D folded paper-based microfluidic multichannel detection device consists of a continuous paper-based material that has been processed (such as laser cutting or punching) and has two fold lines, dividing it into three functional areas: a sample pretreatment and distribution section (located in the bottom layer after folding), a longitudinal filtration section (located in the middle layer after folding), and a multi-index color development section (located in the top layer after folding). In its initial state, these three parts are fully unfolded and laid out in a coplanar manner. The area of ​​the first part is larger than the areas of the second and third parts, while the areas of the second and third parts are equal.

[0053] In the first part, the sample pretreatment distribution unit includes a sample injection area located in the center, a reservoir area distributed around the sample injection area, and an immunoassay area (which may not include an immunoassay area). A flow channel is provided between the sample injection area and the reservoir area, and a flow channel is also provided between the sample injection area and the immunoassay area. There is one and only one sample injection area, and the number of reservoir areas can be two, three, or even more. The number of immunoassay areas can be one or more. The number of flow channels is equal to the sum of the number of reservoir areas and the number of immunoassay areas.

[0054] In one specific embodiment, this application takes the detection of three liquid indicators, namely creatinine, uric acid and albumin, in whole blood samples as an example. That is, there are two reservoir areas and one immunoassay area. Correspondingly, there are two filtrate areas on the longitudinal filtrate section and two color development areas on the multi-indicator color development section.

[0055] like Figures 1a-1bAs shown in the figure, taking the orientation shown in the figure as an example, the 3D folded paper-based microfluidic multichannel detection device includes a sample pretreatment and distribution unit 1 located on the right side of the figure during the folding process, a longitudinal filtrate unit 2 located in the middle of the figure during the folding process, and a multi-index color development unit 3 located on the left side of the figure during the folding process. Figure 1a The storage area, filtrate area, and color development area shown are the front side; the back side is not shown. On the sample pretreatment distribution unit 1, two flow channels 14 and 15 are arranged side by side on the left side of the sample injection area 10, and the ends of the two flow channels 14 and 15 are respectively connected to two storage areas 11 and 12; a flow channel 16 is arranged on the right side of the sample injection area 10, and the end of the flow channel 16 is integrated with a lateral chromatography device 13 (i.e., LFA protein test strip) for immunoassay of the liquid indicator protein.

[0056] exist Figure 1a In the sample pretreatment distribution unit 1, a longitudinal filtration section 2 is provided on the left side of the two liquid storage areas 11 and 12. Two corresponding filtration areas 20 and 21 are arranged side-by-side on the longitudinal filtration section 2. When the longitudinal filtration section 2 is folded above the sample pretreatment distribution unit 1, the two filtration areas 20 and 21 completely cover the area directly above the two liquid storage areas 11 and 12 (see [reference]). Figure 1b That is, the front sides of the filtrate zones 20 and 21 completely overlap with the front sides of the storage zones 11 and 12. A multi-index colorimetric unit 3 is provided on the left side of the two filtrate zones 20 and 21. Two corresponding colorimetric zones 30 and 31 are arranged side-by-side on the multi-index colorimetric unit 3. When the multi-index colorimetric unit 3 is folded above the longitudinal filtrate section 2 and the sample pretreatment distribution section 1, the two colorimetric zones 30 and 31 completely cover the top of the two filtrate zones 20 and 21, that is, the back sides of the colorimetric zones 30 and 31 completely overlap with the back sides of the filtrate zones 20 and 21. See [reference needed] after folding. Figure 1b That is, the sample pretreatment distribution unit 1, the longitudinal filtrate unit 2, and the multi-index color development unit 3 are arranged adjacent to each other from bottom to top.

[0057] This 3D folded paper-based microfluidic multichannel detection device, when folded, has a vertical configuration of tightly stacked components from bottom to top, forming a vertical capillary flow path (liquid storage area → filtrate area → color development area). It utilizes gravity to assist particle sedimentation while ensuring unidirectional upward migration of the clarified liquid phase, thereby enhancing the efficiency of sample separation.

[0058] In this embodiment, the sample solution used is the collected whole blood sample, and the liquid indicators used are creatinine, uric acid, albumin, etc. The colorimetric area 30 can be set as the colorimetric area for creatinine detection, and the colorimetric area 31 can be set as the colorimetric area for uric acid detection. The two colorimetric areas 30 and 31 are completely independent and do not communicate with each other. The reservoir areas 11 and 12 store whole blood samples containing agglutinated red blood cells; the filtrate areas 20 and 21 store serum after filtering the agglutinated red blood cells.

[0059] In this application, the storage areas 11 and 12 are mainly used to homogenize the sample, and the front side is also solidified with a coagulant, which can further enhance the aggregation of red blood cells in the whole blood sample; the front and back sides of the filtrate areas 20 and 21 can be solidified with a coagulant to enhance the filtration of the whole blood sample.

[0060] In this application, surface modification is performed on the flow channels 14, 15, and 16 of the sample pretreatment distribution section 1 to initially achieve particle aggregation. After the whole blood sample is evenly distributed in the storage areas 11 and 12 of the sample pretreatment distribution section 1, it is folded to form longitudinally uniform liquid flow conditions. By utilizing the characteristic that aggregated red blood cells are more difficult to flow longitudinally, combined with the filtration areas 20 and 21 of the longitudinal filtration section 2, further filtration of the whole blood sample is achieved, avoiding color interference of red blood cells on the colorimetric reaction. The colorimetric reaction reagent is solidified in the colorimetric areas 30 and 31 of the multi-index colorimetric section 3, and the filtered serum undergoes a colorimetric reaction here to achieve colorimetric detection of the detection target.

[0061] In the above embodiments, Figure 2 This is a comparison of the standard curves for creatinine detection using the 3D folded paper-based microfluidic multichannel detection device described in this application and an existing device (without a filter structure). The horizontal axis represents creatinine concentration (mg / dL), and the vertical axis represents the intensity of the RGB red channel in the colorimetric region. The experimental group used the 3D folded paper-based microfluidic multichannel detection device, while the control group used the existing device. Figure 2 The results show that the detection signal of the 3D folded paper-based microfluidic multichannel detection device in this application has a highly linear relationship with the concentration (R² = 0.9829), while the linearity of the existing device in the control group is poor (R² = 0.2181), proving that the design of the longitudinal filtrate section 2 of this application significantly improves the detection linearity.

[0062] In the first part (sample pretreatment distribution section 1), calcium ions can be used as the coagulant solidified in channels 14, 15, and 16 to pre-agglutinate red blood cells in whole blood samples. This innovatively utilizes the property that solid-liquid separation naturally occurs when whole blood samples pass longitudinally through Whatman No. 3 filter paper, achieving more thorough serum separation in the second part (longitudinal filtrate section 2). The mechanism is that the agglutinated red blood cell clusters are less likely to pass longitudinally through the porous structure of Whatman No. 3 filter paper and are deposited downwards under gravity, while serum can naturally flow upwards longitudinally under the influence of fibers. This effect is triggered when the second part folds back to the first part and when the third part (multi-index colorimetric section 3) folds back to the second part. By repeatedly utilizing this mechanism, effective separation of red blood cells and serum in whole blood samples is achieved, and the detection linearity is greatly improved (experimental results are shown in Figure 1). Figure 2 (As shown).

[0063] In the above embodiments, Figure 3 The image shows a histogram comparing the H-color values ​​of the 3D folded paper-based microfluidic multichannel detection device in this application with those of an existing device (without an end reservoir structure), used to quantitatively compare the color characteristics of the 3D folded paper-based microfluidic detection device in the experimental group and the existing device in the control group after the colorimetric reaction. Figure 3 The H-color value of the existing device in the control group on the left is 210; Figure 3 The H-hue value of the proposed 3D folded paper-based microfluidic multichannel detection device, shown on the right, is 216. The results indicate that a higher H-hue value signifies a stronger signal output, which helps improve the ability to identify low-concentration sample solutions, thereby enhancing resolution. The end-sump design of this application effectively suppresses the coffee ring phenomenon, significantly improving color uniformity and detection resolution.

[0064] In this application, a liquid storage area at the end of the flow channel is introduced into the structure of the first part of the 3D folded paper-based microfluidic multichannel detection device. This liquid storage area structure is coordinated with the folding form. By waiting for the sample liquid to uniformly fill the liquid storage area and stop flowing, the second part is folded in sequence and the third part is folded in the reverse direction. This changes the flow mode of the sample liquid. The way the liquid flows from the flow channel into the color development area is changed from the traditional flow mode of simultaneous horizontal and vertical flow (side flow with osmosis) to the flow mode of this application, which first flows horizontally and then stops, and then the vertical flow becomes the main flow. This reduces the horizontal elution effect inside the color development area, suppresses the formation of coffee ring phenomenon, and thus ultimately improves the color development uniformity and detection resolution (experimental results are shown in the figure). Figure 3 (As shown).

[0065] It should be noted that the pad structure refers to the physical carrier form of a paper-based microfluidic detection device. It is typically a disposable, portable detection chip or test strip card made by cutting, stacking, functionalizing, and folding multiple layers of filter paper or other porous materials (such as Whatman filter paper). Pad is a general term for paper-based detection platforms in the fields of microfluidics and point-of-care testing; while mpad (microfluidic paper chip) is a paper-based detection platform that uses capillary action to drive liquids to complete multi-step biochemical analysis by constructing hydrophilic / hydrophobic patterns on filter paper to form controllable microchannels and reaction zones. The 3D folded paper-based microfluidic multichannel detection device designed in this application is based on the mpad structure and has strong scalability. For example, it successfully integrates with the lateral chromatography device 13 in channel 16, realizing the detection of protein macromolecules and integrating colorimetric and immunochromatographic detection modes.

[0066] [Specific Implementation Examples of a Method for Simultaneous Detection of Multiple Liquid Indicators]

[0067] like Figure 4As shown, this application provides a method for simultaneous detection of multiple liquid indicators, which uses any of the above-described 3D folded paper-based microfluidic multichannel detection devices to simultaneously detect multiple liquid indicators in a sample solution, comprising:

[0068] S101: The sample solution is added dropwise to the sample injection area of ​​the sample pretreatment distribution section, and the sample solution flows laterally from the injection area to the storage area along the flow channel.

[0069] In addition, as an extension, the end of one of the channels is connected to the sample inlet of the lateral chromatography device, and the ends of the other channels are connected to the storage area. The sample solution flows laterally along the channels and flows to the storage area and the sample inlet of the lateral chromatography device, respectively.

[0070] S102: After the sample liquid in the storage area stops flowing and is evenly distributed, fold the longitudinal filtrate section to fit tightly against the front of the filtrate area and the front of the storage area, so that the sample liquid is filtered into the filtrate area by longitudinal permeation.

[0071] S103: After the filtered sample solution has evenly filled the filtrate area, the multi-index colorimetric part is folded back to the back of the colorimetric area and closely adhered to the back of the filtrate area, so that the filtered sample solution enters the front of the colorimetric area in a longitudinal permeation manner and a colorimetric reaction occurs.

[0072] S104: After the colorimetric reaction is fully completed, insert the 3D folded paper-based microfluidic multichannel detection device into the multichannel quantitative colorimetric reading device, and quantitatively output the values ​​of multiple liquid indicators through the supporting application.

[0073] In the embodiments of this application, the sample solution is dropped into the sample inlet area of ​​the 3D folded paper-based microfluidic multichannel detection device. The sample solution flows laterally along the flow channels 14, 15, and 16 of the sample pretreatment distribution section 1, and finally stops at the end storage areas 11 and 12, gradually distributing evenly. Specifically, after the sample solution has evenly filled the storage areas 11 and 12, the longitudinal filtration section 2 is folded to the right for the first time (see...). Figure 1a (See the arrow in the image) so that the front sides of the two independent filtrate zones 20 and 21 of the longitudinal filtrate section 2 are fully aligned with the front sides of the two independent reservoir zones 11 and 12, respectively. The serum in the whole blood sample slowly fills the filtrate zones 20 and 21 in a three-dimensional longitudinal flow manner. After the sample solution has evenly filled the front sides of the filtrate zones 20 and 21, the multi-index colorimetric section 3 is folded in the opposite direction (see the image). Figure 1a(The arrow in the middle indicates that the multi-index colorimetric section 3 is folded to the left), so that the back sides of the two independent colorimetric areas 30 and 31 in the multi-index colorimetric section 3 are fully attached to the back sides of the two independent filtrate areas 20 and 21 respectively. The serum in the whole blood sample slowly fills the front side of the colorimetric areas 30 and 31 in a three-dimensional longitudinal flow manner and a colorimetric reaction occurs. After the colorimetric reaction has fully occurred, the 3D folded paper-based microfluidic multi-channel detection device is inserted into the multi-channel quantitative colorimetric reading device 4. After the mobile phone is connected to the multi-channel quantitative colorimetric reading device 4, the values ​​of multiple liquid indicators can be read in the mobile phone App.

[0074] By integrating a lateral chromatography device 13 (such as an LFA test strip) into the flow channel 16, the measurement range of this 3D folded paper-based microfluidic multichannel detection device can be broadened. For example, if the sample inlet of an LFA test strip used to detect albumin is fixed at the end of the flow channel 16 of the sample pretreatment distribution unit 1, the sample solution can flow into the LFA test strip after pretreatment and enter the cross-flow immunoassay process, and finally read the albumin value.

[0075] In summary, this application provides a 3D folded paper-based microfluidic multichannel detection device and method. This device, through a three-stage collaborative design of a sample pretreatment distribution section – a longitudinal filtrate section – and a multi-index colorimetric section, integrates automatic sample filtration, multi-channel distribution, chemical colorimetry, and immunochromatography. It significantly improves the accuracy, uniformity, and linearity of detection, and achieves one-stop, simultaneous, and real-time detection of multiple liquid indicators. It boasts advantages such as ease of operation, low cost, and strong scalability. This method, through the coordinated structure and folding sequence of the device, alters the traditional flow pattern of the sample solution, weakens the lateral elution effect within the colorimetric zone, and suppresses the formation of the coffee ring phenomenon, thereby ultimately improving colorimetric uniformity and detection resolution. The longitudinal filtrate section employs an independent filtrate zone, which, combined with the design of overlapping with the end reservoir after folding, achieves efficient sample separation, significantly reducing the interference of particulate components in the sample solution on the colorimetric reaction, thereby improving the linear correlation between the detection signal and the concentration of the liquid indicator.

[0076] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, is used to perform the above-described method for simultaneous detection of multiple liquid indicators, the method for simultaneous detection of multiple liquid indicators including at least one of the schemes described in the above embodiments.

[0077] The computer storage medium in this application embodiment can be any combination of one or more computer-readable media. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. For example, a computer-readable storage medium can be, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0078] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0079] The program code contained on a computer-readable medium may be transmitted using any suitable medium, including, but not limited to, wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0080] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0081] Furthermore, the terms "first, second, third, etc." or similar terms such as module A, module B, and module C used in the specification and claims are only used to distinguish similar objects and do not represent a specific ordering of objects. It is understood that, where permissible, a specific order or sequence may be interchanged so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0082] In the above description, the labels of the steps involved do not necessarily mean that the steps will be executed in a certain order. The order of the steps can be interchanged or executed simultaneously if permitted.

[0083] The term "comprising" as used in the specification and claims should not be construed as limiting itself to what follows; it does not exclude other elements or steps. Therefore, it should be interpreted as specifying the presence of the mentioned feature, integral, step, or component, but does not exclude the presence or addition of one or more other features, integrals, steps, or components, or groups thereof. Thus, the statement "device comprising means A and B" should not be limited to a device consisting solely of components A and B.

[0084] Unless otherwise defined, all technical and scientific terms used throughout this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning as stated in this application or derived from the content described herein shall prevail. Furthermore, the terminology used in this description is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0085] Note that the above are merely preferred embodiments and the technical principles employed in this application. Those skilled in the art will understand that this application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the technical concept of this application, all of which fall within the scope of protection of this application.

[0086] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A 3D folded paper-based microfluidic multi-channel detection device, characterized in that, The main body of the detection device includes a first part, a second part disposed at one end of the first part, and a third part disposed at the other end of the second part. The first part is a sample pretreatment and dispensing section, the second part is a longitudinal filtrate section, and the third part is a multi-index colorimetric section. The sample pretreatment distribution unit includes a sample injection area located in the center and multiple channels distributed around the sample injection area. A liquid storage area is provided at the end of each channel. A coagulant is solidified on the surface of both the channel and the liquid storage area. The longitudinal filtrate section includes multiple independent filtrate zones arranged in parallel, and the coagulant is solidified on the surface of the filtrate zones. The multi-index colorimetric section includes multiple independently arranged colorimetric zones, and each colorimetric zone is respectively cured with colorimetric reaction reagents corresponding to multiple liquid indices in the sample solution. The 3D folded paper-based microfluidic multichannel detection device undergoes two folding states in sequence during use, and the longitudinal filtrate section is folded before the multi-index color development section. In the first folding state, the longitudinal filtrate section has been folded forward to overlap with the front of the filtrate area and the front of the liquid storage area in the corresponding position. In the second folded state, the multi-index colorimetric section is further folded back to overlap with the back of the colorimetric area and the back of the filtrate area in the corresponding position.

2. The 3D folded paper-based microfluidic multi-channel detection device according to claim 1, characterized in that, The longitudinal filtrate section uses Whatman No. 3 filter paper or alternative filter paper with equivalent pore size and capillary properties.

3. The 3D folded paper-based microfluidic multi-channel detection device according to claim 1, characterized in that, The number of the liquid storage zone, the number of the filtrate zone, and the number of the color development zone are equal.

4. The 3D folded paper-based microfluidic multi-channel detection device according to claim 3, characterized in that, One of the flow channels is also connected to the sample inlet of a lateral chromatography device.

5. The 3D folded paper-based microfluidic multi-channel detection device according to claim 4, characterized in that, The number of flow channels is not less than the number of liquid storage zones.

6. The 3D folded paper-based microfluidic multi-channel detection device according to claim 1, characterized in that, When neither the longitudinal filtrate section nor the multi-index colorimetric section is folded, the sample pretreatment distribution section, the longitudinal filtrate section, and the multi-index colorimetric section are arranged adjacent to each other and laid out in a coplanar manner.

7. A method for simultaneous detection of multiple liquid indicators, characterized in that, The simultaneous detection of multiple liquid parameters in a sample solution using the 3D folded paper-based microfluidic multichannel detection device according to any one of claims 1-6 includes: The sample solution is added dropwise to the injection area of ​​the sample pretreatment distribution section, and the sample solution flows laterally from the injection area to the storage area along the flow channel. After the sample liquid in the storage area stops flowing and is evenly distributed, the longitudinal filtrate section is folded to fit tightly against the front of the filtrate area and the front of the storage area, so that the sample liquid is filtered to the back of the filtrate area in a longitudinal permeation manner. After the filtered sample solution evenly fills the filtrate area, the multi-index colorimetric part is folded back to the back of its colorimetric area and closely adheres to the back of the filtrate area, so that the filtered sample solution enters the front of the colorimetric area in the longitudinal permeation manner and a colorimetric reaction occurs. After the colorimetric reaction is fully completed, the 3D folded paper-based microfluidic multi-channel detection device is inserted into the multi-channel quantitative colorimetric reading device, and the values ​​of multiple liquid indicators are quantitatively output through the supporting application.

8. The method for simultaneous detection of multiple liquid indicators according to claim 7, characterized in that, The surface of the liquid storage area and the surface of the flow channel are solidified with a coagulant. During the process of the sample liquid flowing laterally in the flow channel and the sample liquid uniformly filling the liquid storage area, the coagulant pre-treats the sample liquid, wherein the pre-treatment includes particle agglomeration treatment of the sample liquid.

9. The method for simultaneous detection of multiple liquid indicators according to claim 8, characterized in that, The longitudinal filtrate section uses Whatman No. 3 filter paper or an alternative filter paper with equivalent pore size and capillary properties. The coagulant is cured on the surface of the filtrate zone in the longitudinal filtrate section. After the longitudinal filtrate section is folded so that the front side of the filtrate zone is tightly attached to the front side of the storage zone, the sample liquid located in the storage zone is filtered along the front side of the filtrate zone to the back side of the filtrate zone under the coagulation action of the coagulant.

10. The method for simultaneous detection of multiple liquid indicators according to claim 8, characterized in that, Also includes: The sample solution flows laterally along one of the flow channels to the inlet end of the lateral chromatography device; The detection line signal and the quality control line signal of the lateral chromatography device are synchronously acquired and quantitatively analyzed by the multi-channel quantitative colorimetric reading device.

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