A centrifugal microfluidic chip and detection method

Abstract

The application discloses a centrifugal microfluidic chip and a detection method. The centrifugal microfluidic chip comprises a substrate and a detection unit arranged on the substrate. The detection unit comprises a reagent sample hole, a first sample hole, a second sample hole, a first diffusion channel and a second diffusion channel. The first sample hole and the second sample hole are arranged at the end away from the center of the reagent sample hole along the radial direction of the substrate. The first sample hole and the second sample hole are arranged at intervals along the circumferential direction of the substrate. One end of the first diffusion channel and one end of the second diffusion channel are communicated with the reagent sample hole. The other end of the first diffusion channel is communicated with the first sample hole. The second end of the second diffusion channel is communicated with the second sample hole. The sulfonamide residue can be rapidly detected by using the microfluidic chip combined with gold nano materials.

Description

Technical Field

[0001] This application relates to the field of microfluidic chip technology, and in particular to a centrifugal microfluidic chip and a detection method thereof. Background Technology

[0002] Food may introduce harmful substances during processing, transportation, and storage, such as veterinary drug residues, heavy metal residues, pesticide residues, and pathogens, threatening food quality and safety. Therefore, it is necessary to explore accurate, efficient, sensitive, and economical detection methods to ensure food safety. Microfluidic chips are devices that manipulate fluids using tiny, narrow channels and chamber structures, enabling high-sensitivity, high-speed, high-throughput, and low-cost analysis. They integrate multiple functional modules, including sample separation, enrichment, mixing, derivatization, reaction, and detection, onto a single microchip. Manipulating fluids within channels with a width or depth of micrometers offers advantages such as low sample consumption, short reaction time, ease of use, high product conversion rate, and minimal waste generation. Integrating multi-sample analysis and detection onto microfluidic chips can effectively solve problems in biochemical sample analysis, such as low detection sensitivity, poor signal reproducibility, and susceptibility to sample contamination in open systems. Furthermore, it enables rapid and sensitive detection of target substances in microliters or even nanoliters of biochemical liquids.

[0003] Sulfonamides are a class of synthetic antibiotics that can inhibit the growth and reproduction of bacteria. Their high efficiency and low cost make them widely used in animal husbandry.

[0004] In related technologies, food safety testing can employ methods such as gas chromatography and high-performance liquid chromatography, but these methods suffer from drawbacks such as cumbersome procedures, high costs, long processing times, and the need to be conducted in a laboratory setting. Building on this, peroxidase mimics based on nanomaterials, including graphene oxide (GO), carbon nanotubes, carbon dots, and gold nanoparticles, have shown promising applications in recent years. This is because peroxidase mimics based on nanomaterials exhibit greater resistance to denaturation or protease digestion than natural enzymes. Furthermore, they offer advantages such as low preparation costs, relatively simple storage, more flexible design, and the ability to be mass-produced. Gold nanoclusters also possess unique characteristics such as excellent fluorescence properties, ultra-small size, and good biocompatibility, making them promising for applications in environmental monitoring, bioimaging, disease diagnosis, and treatment. Summary of the Invention

[0005] To solve at least one of the above-mentioned technical problems, this application provides a centrifugal microfluidic chip and a detection method, which can use a microfluidic chip combined with nanomaterials to rapidly detect sulfonamide residues. The technical solution adopted is as follows.

[0006] In a first aspect, the centrifugal microfluidic chip provided in this application includes a substrate and a detection unit. The substrate has a center. The detection unit is disposed on the substrate and includes a reagent inlet, a first sample port, a second sample port, a first diffusion channel, and a second diffusion channel. The reagent inlet is used to inject reagent. Along the radial direction of the substrate, the first sample port and the second sample port are respectively disposed at the end of the reagent inlet port away from the center. The first sample port and the second sample port are spaced apart along the circumference of the substrate. One end of the first diffusion channel and the second diffusion channel are both connected to the reagent inlet port, the other end of the first diffusion channel is connected to the first sample port, and the second end of the second diffusion channel is connected to the second sample port.

[0007] In some embodiments of this application, the detection unit further includes a sample delivery structure, the sample delivery structure including a sample delivery channel for injecting a sample to be tested, the sample delivery channel including a corner segment, the corner segment being disposed adjacent to the first sample hole, and the first sample hole being located inside the corner of the corner segment, the corner segment communicating with the first sample hole, so that the sample to be tested enters the first sample hole through the corner segment.

[0008] In some embodiments of this application, the sample delivery structure further includes a third sample hole and a waste liquid hole. One end of the sample delivery channel is connected to the third sample hole, and the other end is connected to the waste liquid hole. The corner section is located between the third sample hole and the waste liquid hole. The third sample hole is used to inject the sample to be tested, and the waste liquid hole is used to guide the sample to be tested to flow into the waste liquid hole.

[0009] In some embodiments of this application, the sample delivery channel is configured as a hydrophobic structure.

[0010] In some embodiments of this application, the sample delivery structure further includes a connecting channel, which is disposed between the corner segment and the first sample hole to connect the corner segment and the first sample hole, and the connecting channel is bent toward the first sample hole.

[0011] In some embodiments of this application, the length of the first diffusion channel is the same as the length of the second diffusion channel, and the angle bisector of the angle formed by the first diffusion channel and the second diffusion channel extends radially along the substrate.

[0012] In some embodiments of this application, the centrifugal microfluidic chip includes a plurality of detection units, which are spaced apart circumferentially along the substrate.

[0013] Secondly, this application also provides a detection method, including the following steps:

[0014] Inject gold nanoparticle reagents into the reagent inlet wells and centrifuge the substrate to disperse the gold nanoparticle reagents from the reagent inlet wells into the first and second sample wells.

[0015] The sample to be tested is injected into the third sample well so that the analyte in the sample enters the first sample well through the corner section of the sample delivery channel;

[0016] Inject the standard into the second sample well;

[0017] Inject dye into the reagent injection well and centrifuge the substrate to disperse the dye from the reagent injection well into the first and second sample wells.

[0018] In some embodiments of this application, after injecting dye into the reagent inlet well and centrifuging the substrate, the detection method further includes...

[0019] Compare the colors of the first and second sample wells to determine whether the concentration of the sample to be tested exceeds the concentration of the standard.

[0020] In some embodiments of this application, after injecting the sample to be tested into the third sample well so that the analyte in the sample enters the first sample well through the corner section of the sample delivery channel, the detection method further includes...

[0021] After the analyte in the sample enters the first sample well, the analyte in the sample is mixed with the gold nanoparticle reagent and incubated for 0.5 to 2 minutes.

[0022] In some embodiments of this application, the step of injecting the sample to be tested into the third sample well so that the analyte in the sample enters the first sample well through the corner section of the sample delivery channel includes...

[0023] The sample solution flows from the third sample well to the waste liquid well and through the corner section. The analyte in the sample enters the first sample well from the corner section through back extraction.

[0024] In some embodiments of this application, the analyte in the sample to be tested includes sulfamethoxazole.

[0025] The embodiments of this application have at least the following beneficial effects: Utilizing a first diffusion channel and a second diffusion channel arranged radially along the substrate, the reagent in the reagent inlet can be dispersed into the first and second sample wells under the centrifugal action of the substrate. The first sample well can be used for the reaction of the test sample, and the second sample well is used for the reaction of the standard. After the test sample and the standard have reacted with the reagent, the colors in the first and second sample wells can be compared to determine whether the sulfonamide residue concentration in the test sample exceeds the concentration in the standard, thus determining whether the residue concentration in the test sample exceeds the standard. On the one hand, the colorimetric detection method described above can quickly determine whether the concentration of sulfonamide residue exceeds the standard, thereby improving the efficiency of sulfonamide residue detection. On the other hand, using a microfluidic chip structure to detect sulfonamide residues, since the dimensions of the channels and reaction chambers on the substrate are approximately at the micrometer level, can reduce the amount of sample used, thereby reducing sample consumption, shortening the reaction time between the sample and the reagent, and improving detection efficiency and ease of operation. Meanwhile, the first diffusion channel, the second diffusion channel, the first sample well, and the second sample well on the substrate are set independently, allowing the reagents, the test samples, and the standards to react separately without interference. This avoids problems such as contamination during the reaction process, which helps to improve the sensitivity and accuracy of the detection and ensures the reliability of the detection results. Attached Figure Description

[0026] The aspects and advantages described and / or added to the embodiments of this application will become apparent and readily understood in conjunction with the following drawings. It should be noted that the embodiments illustrated in the following drawings are exemplary and are used only to explain this application, and should not be construed as limiting this application.

[0027] Figure 1 This is a schematic diagram of the centrifugal microfluidic chip structure provided in the embodiments of this application;

[0028] Figure 2 A schematic diagram of the detection unit of the centrifugal microfluidic chip provided in the embodiments of this application;

[0029] Figure 3 for Figure 2 AA cross-section view;

[0030] Figure 4 for Figure 2 A magnified view of section B;

[0031] Figure 5 A flowchart of the detection method provided in the embodiments of this application.

[0032] Reference numerals: 100, centrifugal microfluidic chip; 10, substrate; 20, detection unit; 21, reagent inlet; 22, first sample port; 23, second sample port; 24, first diffusion channel; 25, second diffusion channel; 26, sample delivery structure; 261, sample delivery channel; 2610, corner section; 2611, first flow section; 2612, second flow section; 262, third sample port; 263, waste liquid port; 264, connecting channel. Detailed Implementation

[0033] The following is combined Figures 1 to 5 The embodiments of this application are described in detail below, examples of which are illustrated 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 application, and should not be construed as limiting this application.

[0034] In the description of this application, it should be understood that the use of terms such as "center," "middle," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" to indicate orientation or positional relationships is based on the orientation or positional relationships shown in the accompanying drawings and is only for the convenience of describing this application and simplifying the description, and does 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 application. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0035] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" 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 between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0036] Firstly, please refer to Figures 1 to 4This application provides a centrifugal microfluidic chip 100, including a substrate 10 and a detection unit 20 disposed on the substrate 10. The substrate 10 has a center O. The detection unit 20 includes a reagent inlet 21, a first sample hole 22, a second sample hole 23, a first diffusion channel 24, and a second diffusion channel 25. The reagent inlet 21 is used for injecting reagents. Along the radial direction of the substrate 10, the first sample hole 22 and the second sample hole are respectively disposed at the end of the reagent inlet 21 away from the center O, and the first sample hole 22 and the second sample hole 23 are spaced apart along the circumferential direction of the substrate 10. One end of the first diffusion channel 24 and the second diffusion channel 25 are both connected to the reagent inlet 21, the other end of the first diffusion channel 24 is connected to the first sample hole 22, and the second end of the second diffusion channel 25 is connected to the second sample hole 23. Using the first diffusion channel 24 and the second diffusion channel 25 arranged radially along the substrate 10, the reagent in the reagent inlet 21 can be dispersed into the first sample well 22 and the second sample well 23 under the centrifugation of the substrate 10. The first sample well 22 can be used for the reaction of the test sample, and the second sample well 23 is used for the reaction of the standard. After the test sample and the standard have reacted with the reagent, the colors in the first sample well 22 and the second sample well 23 can be compared to determine whether the concentration of the test sample (e.g., sulfamethoxazole, hereinafter referred to as sulfanilamide residue) exceeds the concentration in the standard, thus determining whether the residue concentration in the test sample exceeds the standard. On the one hand, this colorimetric detection method can quickly determine whether the concentration of sulfanilamide residue exceeds the standard, thereby improving the efficiency of sulfanilamide residue detection. On the other hand, the centrifugal microfluidic chip 100 structure is used to detect sulfonamide residues. Since the flow channels (e.g., the first diffusion channel 24 and the second diffusion channel 25) and reaction chambers (e.g., the first sample well 22 and the second sample well 23) on the substrate 10 are approximately micrometer-sized, the amount of sample (e.g., test sample, standard, reagent, etc.) required can be reduced, thus lowering sample consumption, shortening the reaction time between the sample and reagent, and improving detection efficiency and ease of operation. Simultaneously, the first diffusion channel 24, the second diffusion channel 25, and the first sample well 22 and the second sample well 23 on the substrate 10 are independently configured, allowing reagents, test samples, and standards to react separately without interference. This avoids contamination during the reaction process, improving detection sensitivity and accuracy, and ensuring the reliability of the detection results.

[0037] For example, the substrate 10 can be configured as a circular or elliptical structure. When the substrate 10 is centrifuged, the substrate 10 can rotate around the center O without changing the position of the center O. Under centrifugal action, the material in the flow channel outside the center O can flow radially from the center O to the circumference of the substrate 10.

[0038] Optionally, the sample to be tested is usually extracted with an organic solvent, while the reagent in the first sample well 22 is an aqueous solution. The two are difficult to mix directly, so the sample to be tested usually cannot be directly added to the first sample well 22. Therefore, in order to facilitate the test reagent to enter the first sample well 22 better, in some embodiments, the detection unit 20 further includes a sample delivery structure 26. The sample delivery structure 26 includes a sample delivery channel 261 for injecting the sample to be tested. The sample delivery channel 261 includes a corner section 2610. The corner section 2610 is located adjacent to the first sample well 22, and the first sample well 22 is located inside the corner of the corner section 2610. The corner section 2610 is connected to the first sample well 22 so that the test component in the sample to be tested enters the first sample well 22 through the corner section 2610. Using the sample delivery channel 261, the sample to be tested can be back-extracted into the first sample well 22 as it passes through the channel. This means the extracted substance can return from the organic phase to the aqueous phase. On one hand, while ensuring the back-extraction of sulfonamides, this prevents organic solutions in the sample from entering the first sample well 22, thus guaranteeing effective reaction between the analyte and other reagents in the first sample well. On the other hand, by placing the first sample well 22 inside the corner, during centrifugation of the substrate 10, the substances in the substrate 10 flow radially from the inside out due to centrifugal force. Therefore, the sample to be tested in the corner section 2610 flows towards the outside of the corner, preventing organic solutions from entering the first sample well 22 and ensuring the accuracy and reliability of the detection.

[0039] In some embodiments, the sample delivery structure 26 further includes a third sample hole 262 and a waste liquid hole 263. One end of the sample delivery channel 261 is connected to the third sample hole 262, and the other end is connected to the waste liquid hole 263. A corner section 2610 is located between the third sample hole 262 and the waste liquid hole 263. The third sample hole 262 is used to inject the sample to be tested, and the waste liquid hole 263 is used to guide the sample to be tested to flow into the waste liquid hole 263. Using the waste liquid hole 263, both ends of the sample delivery channel 261 are connected to the atmosphere through the third sample hole 262 and the waste liquid hole 263, thereby providing power for the sample to be tested to flow in the sample delivery channel 261, ensuring that the sample to be tested can automatically flow in the sample delivery channel 261 using the capillary flow of the channel, and flow through the corner section 2610, so that the sample to be tested can enter the first sample hole 22.

[0040] In some embodiments, the sample delivery channel 261 is configured with a hydrophobic structure. This allows the sample delivery channel 261 to possess hydrophobic properties, enabling the sulfonamide test sample dissolved in an organic solvent to flow along the sample delivery channel 261 from the third sample hole 262 to the waste liquid hole 263 via capillary action. Exemplarily, the hydrophobic properties of the sample delivery channel 261 can be achieved by silanizing the surface of the sample delivery channel 261. For example, a silanizing reagent is obtained by mixing 0.5 mL of dichlorodimethylsilane with 2 mL of n-hexanol. During the treatment, the first sample hole 22 is first blocked, then the silanizing reagent is injected into the third sample hole 262 using a syringe, filling the entire sample delivery channel 261 with the silanizing reagent. After reacting the silanizing reagent with the surface of the sample delivery channel 261 for 15 minutes, the reagent is flushed out of the sample delivery channel 261.

[0041] In some embodiments, the sample delivery channel 261 further includes a first flow section 2611 and a second flow section 2612. The first flow section 2611 connects the third sample hole 262 and the corner section 2610, and the second flow section 2612 connects the corner section 2610 and the waste liquid hole 263. The first flow section 2611 is arranged radially along the substrate 10, and the third sample hole 262 is located on the side of the corner section 2610 facing the center O of the substrate 10. The second flow section 2612 extends from the first sample hole 22 towards the second sample hole 23. In this way, the extending directions of the first flow section 2611 and the second flow section 2612 can form an angle, which is the corner angle of the corner section 2610. By setting the first flow section 2611 to extend radially along the substrate 10, during the centrifugation of the substrate 10, the sample to be tested can flow radially from the center O to the outer periphery of the substrate 10 under the action of centrifugal force. That is, the sample to be tested located in the sample delivery channel 261 can obtain the power to flow from the third sample hole 262 to the corner section 2610, thereby ensuring that the sample to be tested can smoothly pass through the corner section 2610 and be back-extracted to the first sample hole 22. The organic solution in the sample to be tested can continue to enter the waste liquid hole 263 for temporary storage along the second flow section 2612. By setting the second flow section 2612 along the direction from the first sample hole 22 to the second sample hole 23, the space occupied by the second flow section 2612 on the substrate 10 can be reduced, making the entire detection unit 20 more compact and occupying a smaller area, which makes it easier to set up a larger number of detection units 20 on the substrate 10 of the same area.

[0042] In some embodiments, the sample delivery structure 26 further includes a connecting channel 264, which is disposed between the corner section 2610 and the first sample hole 22 to connect the corner section 2610 and the first sample hole 22. The connecting channel 264 is bent toward the first sample hole 22. By using the bent connecting channel 264, the contact area between the connecting channel 264 and the first sample hole 22 can be increased, while the contact area between the first sample hole and the corner section 2610 can be reduced. In this way, while ensuring that the sulfonamide component in the corner section 2610 can be back-extracted to the first sample hole 22, the reagent in the first sample hole 22 is prevented from entering the sample delivery channel 261 and flowing out from the third sample hole 262 and the waste liquid hole 263.

[0043] To ensure that the reagent in the reagent inlet 21 is more evenly dispersed into the first sample well 22 and the second sample well 23, in some embodiments, the length of the first diffusion channel 24 is the same as the length of the second diffusion channel 25, and the angle bisector of the angle formed by the first diffusion channel 24 and the second diffusion channel 25 extends radially along the substrate 10. Thus, the reagent inlet 21, the first sample well 22, and the second sample well 23 approximately form a triangular structure on the surface of the substrate 10, and more specifically, an isosceles triangle. By setting the angle bisector of the apex of this isosceles triangle to extend radially along the substrate 10, the reagent in the reagent inlet 21 can be evenly dispersed into the first diffusion channel 24 and the second diffusion channel 25 during centrifugation of the substrate 10. This ensures that the amount of reagent entering the first sample well 22 and the second sample well 23 is approximately the same, improving the consistency of the detection conditions in the two sample wells during colorimetric detection, thereby ensuring the accuracy of the detection.

[0044] In some embodiments, the microfluidic chip 100 includes a plurality of detection units 20, which are spaced apart circumferentially along the substrate 10. This allows for the simultaneous detection of multiple samples using the plurality of detection units 20 on the substrate 10, thereby improving the detection efficiency of sulfonamide residues. By arranging the detection units 20 circumferentially along the substrate 10, or evenly spaced, for example, each detection unit 20 occupies a roughly fan-shaped space on the substrate 10. The plurality of detection units 20 form multiple fan-shaped structures, which are concentrically arranged. This ensures that the substrate 10 provides the same and uniform centrifugation effect to each detection unit 20 during centrifugation, ensuring the accuracy and reliability of the detection.

[0045] For example, the substrate 10 may be made of glass, and the substrate 10 is formed by bonding two layers of glass. The opposite sides of the two glass layers can be etched with flow channels (e.g., a first diffusion channel 24, a second diffusion channel 25, and a sample delivery channel 261, etc.) by chemical etching. For example, the width of the flow channel is 150-250 μm, such as 150 μm, 200 μm, 220 μm, or 250 μm, and the depth is 20-40 μm, such as 20 μm, 25 μm, 30 μm, 34 μm, or 40 μm.

[0046] Secondly, please refer to Figure 5 This application provides a detection method comprising the following steps:

[0047] S1. Inject gold nanoparticle reagent into the reagent inlet well and centrifuge the substrate to disperse the gold nanoparticle reagent from the reagent inlet well into the first sample well and the second sample well.

[0048] S2. Inject the sample to be tested into the third sample well so that the analyte in the sample enters the first sample well through the corner section of the sample delivery channel;

[0049] S3. Inject the standard into the second sample well;

[0050] S4. Inject the dye into the reagent injection well and centrifuge the substrate to disperse the dye from the reagent injection well into the first and second sample wells.

[0051] For example, the analyte in the sample described above could be sulfamethoxazole. Of course, in other examples, the analyte in the sample could also be other drug residues. The tester can select a reagent that reacts with the drug in the target sample based on the actual needs of the test. The following explanation uses sulfamethoxazole as an example.

[0052] When detecting sulfamethoxazole, BSA-AuNCs gold nanoparticles can be used as the gold nanoparticle reagent. BSA-AuNCs gold nanoparticles possess peroxidase activity, capable of oxidizing dyes (i.e., substrates, such as OPD, or o-phenylenediamine) in the presence of hydrogen peroxide to produce a yellow product, 2,3-diaminophenazine, exhibiting a characteristic absorption peak at 450 nm, resulting in a yellow color. Sulfamethoxazole inhibits the activity of gold nanoparticles. Therefore, by adding the gold nanoparticle reagent to the reagent injection wells and centrifuging the substrate, the gold nanoparticle reagent can be uniformly dispersed into the first and second sample wells. The corner section of the sample delivery channel allows for the back-extraction of sulfamethoxazole extracted with organic solvents into the first sample well, where it mixes and reacts with the gold nanoparticles. Simultaneously, the standard injected into the second sample well also contains sulfamethoxazole; the sulfamethoxazole in the known concentration of the standard also reacts with the gold nanoparticles in the second sample well. Next, the substrate (e.g., OPD and hydrogen peroxide) was uniformly dispersed into the first and second sample wells again using the reagent injection wells. The substrate and the gold nanomaterial in the first sample well reacted with hydrogen peroxide under the catalysis of the reaction and produced a color. The less the gold nanoparticles were inhibited, the more yellow product could be generated, and the deeper the color, indicating a lower sulfonamide content.

[0053] Using the above method to detect sulfonamide residues in the test sample not only allows for direct visual comparison of the colors in the first and second sample wells to determine the relationship between the sulfonamide concentration in the test sample and the concentration in the standard, ensuring the accuracy of the detection, but also improves detection efficiency and shortens the detection time by using colorimetric detection.

[0054] Optionally, the order of operations for steps S2 and S3 can be interchanged or performed simultaneously.

[0055] For example, the gold nanoparticle reagent material may also include a phosphate-acid buffer solution, and the sulfonamide residue may be sulfamethoxazole.

[0056] In some embodiments, after completing step S4 above, the detection method further includes:

[0057] S5. Compare the colors of the first and second sample wells to determine whether the concentration of the sample to be tested exceeds the concentration of the standard.

[0058] By comparing the colors of the products in the first and second sample wells, it can be determined whether the sulfonamide concentration in the test sample exceeds the concentration in the standard. If the color in the first sample well is lighter than that in the second sample well, it indicates that the sulfonamide concentration in the test sample exceeds the concentration in the standard; conversely, if the color in the first sample well is darker than that in the second sample well, it indicates that the sulfonamide concentration in the test sample does not exceed the concentration in the standard. In other examples, the color of the products in the first and second sample wells can also be detected separately or simultaneously using ultraviolet light to determine the sulfonamide concentration in the test sample.

[0059] In some embodiments, after completing step S2 above, the detection method further includes:

[0060] S20. After the analyte in the sample enters the first sample well, the analyte in the sample is mixed with the gold nanoparticle reagent and incubated for 0.5 to 2 minutes, for example, 0.5 minutes, 1 minute, 1.5 minutes, or 2 minutes. This mixing and incubation provides sufficient time for the sample and gold nanomaterials to fully mix, ensuring a complete reaction and improving the accuracy of the detection results.

[0061] In some embodiments, step S2 above further includes the following step:

[0062] S21. The sample solution to be tested flows from the third sample well to the waste liquid well and through the corner section. The analyte in the sample to be tested enters the first sample well from the corner section through back extraction.

[0063] By performing back-extraction at the corner section, it is ensured that the sulfonamide in the test sample can enter the first sample well in the corner section, while preventing the organic solution in the test sample from entering the first sample well. This allows the sulfonamide in the first sample well to fully contact and react with the gold nanoparticle reagent material. For example, the organic solution can be ethyl acetate.

[0064] In the description of this specification, the use of terms such as "an embodiment," "some examples," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples" indicates 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 this application. 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.

[0065] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

[0066] In the description of this application, the presence of a comma ("、") in the patent title indicates an "and" relationship, not an "or" relationship. For example, if the patent title is "A and B", it means that the content claimed in this application is: a technical solution with the subject matter title A and a technical solution with the subject matter title B.

Claims

1. A centrifugal microfluidic chip, characterized in that: include A substrate having a center; A detection unit, disposed on the substrate, comprises: The reagent inlet port is used for injecting reagents. A sample delivery structure, the sample delivery structure including a sample delivery channel for injecting a sample to be tested, the sample delivery channel including a corner section; The first sample hole and the second sample hole are arranged along the radial direction of the substrate, and are respectively located at the end of the reagent inlet hole away from the center. The first sample hole and the second sample hole are arranged at intervals along the circumferential direction of the substrate. A first diffusion channel and a second diffusion channel, one end of which is connected to the reagent inlet, the other end of which is connected to the first sample port, and the second end of which is connected to the second sample port; The corner segment is located adjacent to the first sample hole, and the first sample hole is located inside the corner of the corner segment. The corner segment is connected to the first sample hole so that the sample to be tested can enter the first sample hole through the corner segment. The sample delivery structure also includes a connecting channel, which is located between the corner segment and the first sample hole to connect the corner segment and the first sample hole. The connecting channel is bent toward the first sample hole.

2. The centrifugal microfluidic chip according to claim 1, characterized in that: The sample delivery structure also includes a third sample hole and a waste liquid hole. One end of the sample delivery channel is connected to the third sample hole, and the other end is connected to the waste liquid hole. The corner section is located between the third sample hole and the waste liquid hole. The third sample hole is used to inject the sample to be tested, and the waste liquid hole is used to guide the sample to be tested to flow into the waste liquid hole.

3. The centrifugal microfluidic chip according to claim 2, characterized in that: The sample delivery channel is designed with a hydrophobic structure.

4. The centrifugal microfluidic chip according to any one of claims 1 to 3, characterized in that: The length of the first diffusion channel is the same as the length of the second diffusion channel, and the angle bisector of the angle formed by the first diffusion channel and the second diffusion channel extends radially along the substrate.

5. The centrifugal microfluidic chip according to any one of claims 1 to 3, characterized in that: The centrifugal microfluidic chip includes multiple detection units, which are spaced apart circumferentially along the substrate.

6. A detection method, characterized in that, Applied to the centrifugal microfluidic chip according to any one of claims 1-5, the detection method includes the following steps: Inject gold nanoparticle reagents into the reagent inlet wells and centrifuge the substrate to disperse the gold nanoparticle reagents from the reagent inlet wells into the first and second sample wells. The sample to be tested is injected into the third sample well so that the analyte in the sample enters the first sample well through the corner section of the sample delivery channel; Inject the standard into the second sample well; Inject dye into the reagent injection well and centrifuge the substrate to disperse the dye from the reagent injection well into the first and second sample wells.

7. The detection method according to claim 6, characterized in that: The detection method further includes injecting dye into the reagent injection well, centrifuging the substrate, and then... Compare the colors of the first and second sample wells to determine whether the concentration of the sample to be tested exceeds the concentration of the standard.

8. The detection method according to claim 6, characterized in that: After injecting the sample to be tested into the third sample well, so that the analyte in the sample enters the first sample well through the corner section of the sample delivery channel, the method further includes... After the analyte in the sample enters the first sample well, the analyte in the sample is mixed with the gold nanoparticle reagent and incubated for 0.5 to 2 minutes.

9. The detection method according to claim 6, characterized in that: The step of injecting the sample to be tested into the third sample well, so that the analyte in the sample enters the first sample well through the corner section of the sample delivery channel, includes... The sample solution to be tested flows from the third sample well to the waste liquid well and through the corner section. The analyte in the sample solution enters the first sample well from the corner section through back extraction.

10. The detection method according to claim 6, characterized in that: The analyte in the sample to be tested includes sulfamethoxazole.

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