A microfluidic detection device and method based on quantum dot luminescence

Abstract

This invention discloses a microfluidic detection device based on quantum dot luminescence, comprising a microfluidic chip, including a microfluidic chip body, a sample liquid inlet, a sample chamber, a main channel, at least one branch channel, and at least one detection unit. The detection unit includes a magnetic bead chamber, a mixing channel, a first inverted U-shaped channel, a detection chamber, and a second inverted U-shaped channel arranged sequentially. An electromagnet is located on the back of the detection chamber, which is connected to a three-electrode system. A reagent chamber is located above the detection chamber, and a paraffin valve is located between the reagent chamber and the detection chamber. A heating element is located on the back of the paraffin valve. An electrochemical workstation is also included. At least one detection component includes a rotating filter and a photon counting detector, with the rotating filter facing the front of the detection chamber and the photon counting detector facing the rotating filter. This invention also discloses a microfluidic detection method. The microfluidic chip of this invention is driven entirely by gravity, eliminating the need for an external pump; it can perform simultaneous quantitative detection of multiple viruses.

Description

Technical Field

[0001] This invention relates to the field of microfluidic biodetection technology, and in particular to a microfluidic detection device and microfluidic detection method based on quantum dot luminescence. Background Technology

[0002] Rapid, highly sensitive, and on-site virus detection is a core aspect of infectious disease prevention and control. Among the current mainstream virus detection technologies, RT-PCR has high sensitivity but is complex to operate, relies on large laboratory equipment, and has a long testing cycle; ELISA is simple to operate but lacks sensitivity, is prone to false positives, and cannot achieve simultaneous detection of multiple viruses.

[0003] Microfluidic chip technology integrates sample pretreatment, immune reactions, and other processes onto a micrometer-scale chip, representing a core technological direction for rapid on-site virus detection. However, existing microfluidic virus detection chips still have significant drawbacks: firstly, most require external fluid-driven devices such as syringe pumps or peristaltic pumps, resulting in complex structures; secondly, most existing microfluidic electrochemiluminescence (ECL) detection chips cannot achieve simultaneous quantitative detection of multiple targets, making it difficult to meet the needs of joint detection of various respiratory viruses. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a microfluidic detection device and a microfluidic detection method based on quantum dot luminescence.

[0005] To achieve the above objectives, an embodiment of the present invention provides the following technical solution:

[0006] A microfluidic detection device based on quantum dot luminescence, comprising:

[0007] A microfluidic chip, comprising a microfluidic chip body, a sample liquid inlet, a sample chamber, a main channel, at least one branch channel, and at least one detection unit disposed on and connected in sequence to the microfluidic chip body;

[0008] The detection unit includes a magnetic bead cavity, a mixing channel, a first inverted U-shaped channel, a detection cavity, and a second inverted U-shaped channel arranged sequentially along the fluid flow direction. An electromagnet is located on the back of the detection cavity. The detection cavity is connected to a three-electrode system. A reagent cavity is located above the detection cavity. A paraffin valve is located between the reagent cavity and the detection cavity. A heating element is located on the back of the paraffin valve.

[0009] An electrochemical workstation, which is connected to the three-electrode system;

[0010] At least one detection component, the detection component including a rotating filter and a photon counting detector, the rotating filter facing the front of the detection cavity and the photon counting detector facing the rotating filter.

[0011] As a further improvement of the present invention, the outlet of the first inverted U-shaped flow channel is connected to the upper part of the detection cavity, and the top of the first inverted U-shaped flow channel is higher than the upper edge of the detection cavity.

[0012] As a further improvement of the present invention, the inlet of the second inverted U-shaped flow channel is connected to the lower part of the detection cavity, and the top of the second inverted U-shaped flow channel is flush with the upper edge of the detection cavity.

[0013] As a further improvement of the present invention, the outlet of the second inverted U-shaped flow channel is connected to a waste liquid chamber.

[0014] As a further improvement of the present invention, an exhaust hole is provided at the top of the waste liquid chamber, and a breathable and waterproof membrane is provided at the exhaust hole.

[0015] As a further improvement of the present invention, the sample cavity has an inverted pentagonal cavity structure.

[0016] As a further improvement of the present invention, the mixing channel is a meandering mixing channel with a diameter of 400-800 μm.

[0017] As a further improvement of the present invention, the number of the diversion channels and the detection units is two, both of the diversion channels are connected to the main channel, and the two detection units are respectively connected to the two diversion channels.

[0018] As a further improvement of the present invention, it also includes a support base, the support base being provided with a slot, at least one of the electromagnets and at least one of the heating elements, at least one connector being provided in the slot, the microfluidic chip body being inserted into the slot, the electromagnets facing the back of the detection cavity, and the heating elements facing the back of the paraffin valve.

[0019] A microfluidic detection method, employing the aforementioned quantum dot-based luminescence microfluidic detection device, includes the following steps:

[0020] (1) Sample injection: The viral sample solution is injected into the sample chamber and diverted into the magnetic bead chamber of the detection unit under gravity.

[0021] (2) Capture and enrichment: The freeze-dried nano magnetic beads powder in the magnetic bead cavity is incorporated into the virus sample liquid and enters the mixing channel. The virus combines with the nano magnetic beads to form a magnetic bead-virus complex, which flows into the detection cavity and is fixed by electromagnet adsorption.

[0022] (3) Reagent release: Heating melts the paraffin valve, and the quantum dot probes and co-reactants pre-stored in the reagent chamber flow into the detection chamber under the action of gravity, and incubate to form a "magnetic bead-virus-quantum dot probe" sandwich complex;

[0023] (4) Detection and analysis: The quantum dot electrochemiluminescence is excited by applying a constant potential through a three-electrode system. The luminescence signals of different wavelengths are collected sequentially by switching rotating filters and a photon counting detector to complete the quantitative detection of multiple viruses.

[0024] The beneficial effects of this invention are:

[0025] (1) Full gravity-driven design, no external pump body required, extremely portable: Through the collaborative design of sample chamber, mixing channel, first inverted U-shaped channel, detection chamber, reagent chamber and second inverted U-shaped channel, the fluid is driven by gravity throughout the process, without the need for any external injection pump, peristaltic pump or other driving equipment, and the chip structure is extremely simple.

[0026] (2) All reagents are pre-stored, the closed system prevents contamination, and the operation is extremely simple: the quantum dot probe and co-reactant are pre-stored and sealed through the paraffin valve, and the nano magnetic beads are pre-stored as lyophilized powder, which can achieve long-term storage at room temperature; the detection process only requires one sample addition, and the subsequent whole process is completed in the closed chip without manual sample addition, which completely avoids sample contamination and biosafety risks, and can be operated by non-professionals.

[0027] (3) Double inverted U-shaped flow channel design with high flow control accuracy: The first inverted U-shaped flow channel with its top higher than the upper edge of the detection chamber prevents backflow and avoids reverse contamination of the sample chamber by the fluid; the second inverted U-shaped flow channel with its top flush with the detection chamber achieves precise liquid level control, ensuring that the reagent volume in the detection chamber is constant and the reaction conditions are consistent, which greatly improves the detection accuracy.

[0028] (4) Multicolor quantum dot ECL detection, single chip realizes multi-virus detection: CdSe / CdS / ZnS core-shell quantum dots with three characteristic wavelengths are used to label different viral antibodies. A single detection chamber can simultaneously complete the quantitative detection of three viruses. The dual symmetric unit can be extended to the detection of six viruses. The detection throughput is flexible and controllable. Combined with rotating filter and time synchronization control, crosstalk between different wavelength signals is completely avoided, and the detection specificity and accuracy are excellent.

[0029] (5) Magnetic bead enrichment and meandering mixing enhancement for high detection sensitivity: The virus is efficiently enriched by freeze-dried nano magnetic bead powder, and the binding efficiency of the virus and magnetic beads is enhanced by the meandering mixing channel. Combined with the high signal-to-noise ratio advantage of quantum dot ECL, it meets the detection requirements of low concentration virus samples.

[0030] (6) High integration and compatible with automated detection equipment: It integrates the entire process of sample enrichment, immune reaction, electrochemical excitation and signal detection into one unit. It can realize fully automated timing control of heating plate, electromagnet, potential application, filter switching and signal acquisition through microcontroller. It can be widely used for rapid on-site detection of airborne viruses, clinical samples and environmental samples. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the internal structure of a microfluidic chip according to a preferred embodiment of the present invention;

[0033] Figure 2 This is an exploded view of the microfluidic chip according to a preferred embodiment of the present invention;

[0034] Figure 3 This is an exploded structural diagram of the support base and detection component according to a preferred embodiment of the present invention;

[0035] Figure 4 This is an exploded structural diagram of the microfluidic chip and the carrier according to a preferred embodiment of the present invention;

[0036] Figure 5 This is a front view of a preferred embodiment of the present invention without a housing.

[0037] Figure 6 A schematic diagram of the structure of the outer casing according to a preferred embodiment of the present invention;

[0038] Figure 7 This is a flowchart of a preferred embodiment of the microfluidic detection method of the present invention;

[0039] In the diagram: 1. Microfluidic chip; 10. Microfluidic chip body; 101. Cover plate; 102. Base plate; 11. Sample liquid inlet; 12. Sample chamber; 13. Main channel; 14. Branch channel; 15. Detection unit; 151. Magnetic bead chamber; 152. Mixing channel; 153. First inverted U-shaped channel; 154. Detection chamber; 155. Second inverted U-shaped channel; 156. Electromagnet; 157. Reagent chamber; 158. Paraffin valve; 159. Heating element; 16. Waste liquid chamber; 161. Vent; 2. Electrochemical workstation; 3. Detection component; 31. Rotating filter; 32. Photon counting detector; 4. Three-electrode system; 5. Support; 51. Slot; 52. Connector; 6. Housing. Detailed Implementation

[0040] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0041] Please see Figures 1-5 This application discloses a microfluidic detection device based on quantum dot luminescence, including a microfluidic chip 1, an electrochemical workstation 2, and at least one detection component 3. The microfluidic chip 1 includes a microfluidic chip body 10, a sample liquid inlet 11, a sample chamber 12, a main flow channel 13, at least one branch channel 14, and at least one detection unit 15, all sequentially connected to the microfluidic chip body 10. The detection unit 15 includes a magnetic bead chamber 151, a mixing channel 152, a first inverted U-shaped channel 153, a detection chamber 154, and a second inverted U-shaped channel 155, arranged sequentially along the fluid flow direction. An electromagnet 156 is located on the back of the detection chamber 154, and a three-electrode system 4 is connected to the detection chamber 154. A reagent chamber 157 is located above the detection chamber 154, and a paraffin valve 158 is located between the reagent chamber 157 and the detection chamber 154. A heating element 159 is located on the back of the paraffin valve 158. The electrochemical workstation 2 is connected to the three-electrode system 4. The detection assembly 3 includes a rotating filter 31 and a photon counting detector 32. The rotating filter 31 faces the front of the detection cavity 154, and the photon counting detector 32 faces the rotating filter 31.

[0042] Preferably, the microfluidic chip body 10 is formed by hot-pressing a cover plate 101 and a base plate 102 together, both of which are made of optical-grade polymer material. Preferably, the microfluidic chip body 10 is made of any one of polymethyl methacrylate, polycarbonate, or cyclic olefin copolymer, exhibiting good light transmittance, excellent biocompatibility, and ease of processing and molding. Preferably, the overall dimensions of the microfluidic chip body 10 are 75mm × 50mm × 5mm.

[0043] The sample inlet 11 is preferably located at the top center of the microfluidic chip body 10 and is connected to the sample chamber 12. The sample chamber 12 is preferably an inverted pentagonal cavity structure, which facilitates a relatively large initial gravitational potential energy for the sample liquid, allowing it to flow smoothly under gravity. Its lower pointed end extends into the main flow channel 13. The volume of the sample chamber 12 is preferably 2 mL. The number of flow dividers 14 and detection units 15 is preferably two. Both flow dividers 14 are connected to the main flow channel 13, and the two detection units 15 are connected to the two flow dividers 14 respectively. The main flow channel 13 is divided into two equal-width flow dividers 14, and the two detection units 15 are symmetrically arranged to ensure consistent fluid flow rates in both paths.

[0044] Preferably, the volume of the magnetic bead cavity 151 is 200 μL, and the inlet of the magnetic bead cavity 151 is connected to the diversion channel 14. The magnetic bead cavity 151 is pre-stored with lyophilized nano-magnetic bead powder, which is a superparamagnetic nanoparticle aggregate that has been lyophilized into powder form, and the surface of the nano-magnetic beads is modified with virus capture antibodies.

[0045] The two ends of the mixing channel 152 are respectively connected to the outlet of the magnetic bead cavity 151 and the inlet of the first inverted U-shaped channel 153. Preferably, the mixing channel 152 is a meandering mixing channel with a diameter of 400-800 μm, which is used to prolong the fluid residence time and enhance the mixing of viruses and magnetic nanobeads, so that the viruses and magnetic nanobeads can fully contact and bind, thereby improving virus capture efficiency and detection sensitivity. More preferably, the diameter of the mixing channel 152 is 600 μm. More preferably, the mixing channel 152 is a continuous S-shaped meandering structure. The inner wall of the mixing channel 152 is hydrophilically modified by oxygen plasma.

[0046] Preferably, the outlet of the first inverted U-shaped flow channel 153 is connected to the upper part of the detection chamber 154, and the top of the first inverted U-shaped flow channel 153 is higher than the upper edge of the detection chamber 154 to prevent fluid backflow. More preferably, the top of the first inverted U-shaped flow channel 153 is 3 mm higher than the upper edge of the detection chamber 154.

[0047] The preferred detection cavity 154 has a volume of 600 μL and is positioned directly opposite the rotating filter 31 and the photon counting detector 32. The three-electrode system 4 is fabricated using a screen printing process, which is simple, cost-effective, and suitable for mass production. The three-electrode system 4 includes a working electrode, a platinum wire counter electrode, and an Ag / AgCl reference electrode. The working end of the three-electrode system 4 is located inside the detection cavity 154 and can directly contact the detection reagent. The external port of the three-electrode system 4 is exposed at the lower edge of the microfluidic chip body 10 for connection to the electrochemical workstation 2.

[0048] Preferably, the volume of the reagent chamber 157 is larger than that of the detection chamber 154, and the reagent chamber 157 pre-stores the detection reagent. The reagent chamber 157 and the detection chamber 154 are separated by a paraffin valve 158. The paraffin valve 158 is a sealing structure made of paraffin wax, which is solid at room temperature and melts when heated to 40-60℃, thus connecting the reagent chamber 157 and the detection chamber 154. This allows the detection reagent in the reagent chamber 157 to flow completely into the detection chamber 154 under gravity, and also flushes the inner wall of the detection chamber 154, reducing non-specific adsorption and lowering the background signal. Preferably, the volume of the detection reagent is 900 μL, comprising CdSe / CdS / ZnS core-shell quantum dot probes conjugated with antibodies against the SARS-CoV-2 N protein, influenza A HA antibody, and respiratory syncytial virus F protein, respectively, and the co-reactant K2S2O8. Quantum dots are semiconductor nanocrystals with dimensions ranging from 1 to 10 nm. Due to the quantum confinement effect, their emission wavelength can be continuously tunable by precisely controlling the particle size. This embodiment uses CdSe / CdS / ZnS core-shell structured quantum dots. By controlling the size of the CdSe core, quantum dots with three characteristic emission wavelengths—480 nm blue light, 550 nm green light, and 620 nm red light—were obtained. These quantum dots exhibit advantages such as high quantum yield, good photochemical stability, and narrow half-maximum width at half-maximum (HWHM), making them ideal luminescent markers for multicolor crosstalk-free joint detection. The characteristic emission wavelengths of the three quantum dot probes—480 nm blue light, 550 nm green light, and 620 nm red light—correspond to specific antibodies against three different viruses, i.e., three viral targets.

[0049] Preferably, the inlet of the second inverted U-shaped flow channel 155 is connected to the lower part of the detection chamber 154, and the top of the second inverted U-shaped flow channel 155 is flush with the upper edge of the detection chamber 154, used to control the liquid level in the detection chamber 154 and ensure that the reaction liquid remains in the detection chamber 154. Preferably, the outlet of the second inverted U-shaped flow channel 155 is connected to a waste liquid chamber 16. Preferably, the volume of the waste liquid chamber 16 is 4 mL, used to temporarily store overflowing liquid. Preferably, the top of the waste liquid chamber 16 is provided with a vent 161, and a breathable and waterproof membrane (not shown in the figure) is provided at the vent 161, which can balance the internal air pressure of the microfluidic chip body 1 during the waste liquid storage process, ensuring that the fluid flows smoothly under gravity drive without liquid accumulation or backflow. More preferably, the breathable and waterproof membrane is a polytetrafluoroethylene breathable and waterproof membrane, further ensuring that gas can pass through and liquid leakage is blocked.

[0050] Please see Figure 3 , Figure 4 It also includes a support 5, which is provided with a slot 51, at least one electromagnet 156 and at least one heating element 159. At least one connector 52 is provided in the slot 51. The microfluidic chip body 10 is inserted into the slot 51. The electromagnet 156 faces the back of the detection cavity 154 and the heating element 159 faces the back of the paraffin valve 158.

[0051] Please see Figure 4 , Figure 5 , Figure 6 Furthermore, the electrochemical workstation 2 is preferably housed within the carrier 5. When the microfluidic chip body 10 is inserted into the slot 51, the three-electrode system 4 contacts the connector 52, which in turn connects to the electrochemical workstation 2, thus achieving electrical connection between the three-electrode system 4 and the electrochemical workstation 2. The system also includes a housing 6, with the carrier 5, rotating filter 31, and photon counting detector 32 all housed within the housing 6 for easy portability. Preferably, the electrochemical workstation 2 is model EC-1550A, consisting of a digital signal generator, a data acquisition system, and a potentiostat. Preferably, the rotating filter 31 is driven to rotate by a stepper motor, automatically switching to filter other wavelengths. Preferably, the photon counting detector 32 is model H11890.

[0052] The microfluidic chip in this embodiment is equipped with two sets of symmetrical detection units 15, which share a sample chamber 12 and a waste liquid chamber 16. Each set can detect three types of viruses simultaneously, and a single chip can detect six types of viruses simultaneously. The number of detection units can be flexibly adjusted according to detection requirements.

[0053] Before testing, the sample chamber 12 is placed facing upwards and the ports of the three-electrode system 4 are facing downwards, in a vertical position. The three-electrode system 4 is connected to the miniaturized electrochemical workstation 2. The detection chamber 154 is sequentially aligned with the rotating filter 31 and the photon counting detector 32. The heating element 159, electromagnet 156, electrochemical workstation 2, rotating filter 31, and photon counting detector 32 are all connected to the microcontroller chip to achieve fully automated control of the entire process.

[0054] Please see Figure 7 This application also discloses a microfluidic detection method, which uses the quantum dot-based luminescence microfluidic detection device described in the above embodiments, and includes the following steps:

[0055] (1) Sample injection: The viral sample solution is injected into the sample chamber 12 and diverted into the magnetic bead chamber 151 of the detection unit 15 under gravity drive;

[0056] (2) Capture and enrichment: The freeze-dried nano magnetic bead powder in the magnetic bead cavity 151 is incorporated into the virus sample liquid and enters the mixing channel 152. The virus combines with the nano magnetic beads to form a magnetic bead-virus complex, which flows into the detection cavity 154 and is then adsorbed and fixed by the electromagnet 156.

[0057] (3) Reagent release: Heating melts the paraffin valve 158, and the quantum dot probe and co-reactant pre-stored in the reagent chamber 157 flow into the detection chamber 154 under the action of gravity, and incubate to form a "magnetic bead-virus-quantum dot probe" sandwich complex.

[0058] (4) Detection and analysis: The quantum dot electrochemiluminescence is excited by applying a constant potential through the three-electrode system 4, and the emission signals of different wavelengths are collected sequentially by switching the rotating filter 31 and the photon counting detector 32 to complete the quantitative detection of multiple viruses.

[0059] To better illustrate the microfluidic detection method of the present invention, the following are specific steps.

[0060] 1. Sample injection: Take 1000 μL of the virus sample liquid formed by pretreatment after airborne virus sampling and inject it into the sample chamber 12 through the sample liquid inlet 11. The virus sample liquid is uniformly split into the magnetic bead chambers 151 corresponding to the two sets of detection units 15 under gravity drive through the main channel 13.

[0061] 2. Virus capture and enrichment: The lyophilized nano-magnetic bead powder in the magnetic bead cavity 151 is incorporated into the virus sample liquid and enters the meandering mixing channel 152. The lyophilized nano-magnetic bead powder is dispersed into individual nano-magnetic beads in the virus sample liquid. The fluid is fully mixed in the S-shaped meandering channel with a residence time of ≥30s. The virus in the sample binds specifically and fully to the capture antibody on the surface of the nano-magnetic beads to form a magnetic bead-virus complex.

[0062] 3. Magnetic bead fixation: The magnetic bead-virus complex flows into the detection chamber 154 through the first inverted U-shaped flow channel 153. The microcontroller controls the activation of the electromagnet 156 on the back of the detection chamber 154 to adsorb and fix the magnetic bead-virus complex at the bottom of the detection chamber 154, thus completing the enrichment and fixation of the virus.

[0063] 4. Reagent release: The microcontroller controls the activation of the heating plate 159 on the back of the paraffin valve 158, heating it to 50°C and maintaining it for 30 seconds, melting the paraffin valve 158. The quantum dot probe and co-reactant pre-stored in the reagent chamber 157 flow completely into the detection chamber 154 under the action of gravity.

[0064] 5. Immunoincubation: Incubate at room temperature in the dark for 5 minutes. The specific antibodies on the surface of the quantum dot probe bind specifically to the virus immobilized on the magnetic nanobeads, forming a "magnetic bead-virus-quantum dot probe" sandwich immune complex.

[0065] 6. Electrochemiluminescence excitation: The microcontroller controls the electrochemical workstation 2 to apply a constant potential to the three-electrode system 4 to excite electrochemiluminescence. A potential of -1.0V (relative to the reference electrode) is applied to the working electrode, driving the quantum dots to generate electrochemiluminescence under the action of the co-reactant.

[0066] 7. Multi-wavelength synchronous detection: The microcontroller controls the potential application of the electrochemical workstation 2, the rotation of the rotating filter 31, and the signal acquisition of the photon counter detector 32. The rotating filter 31 switches sequentially in the order of "empty channel → 480nm filter → 550nm filter → 620nm filter", with each channel staying for 5 seconds, corresponding to one complete photon counter detection scan. After the acquisition is completed, the rotating filter 31 switches to the next channel, and the photon counter detector 32 scans again. After the photon counter detector 32 acquires the emission signals of the corresponding wavelengths, the background signal acquired in the empty channel is subtracted to obtain the light signals of the three viruses: COVID-19, H1N1, and RSV. The operating voltage of the photomultiplier tube in the photon counter detector 32 is adjusted for different wavelengths: 750V for the 480nm channel, 800V for the 550nm channel, and 820V for the 620nm channel.

[0067] 8. Signal Processing: After detection, the photon counting detector 32 converts the collected light signal into a count value. After the microcontroller subtracts the background noise and system error, it substitutes the effective light signal intensity corresponding to each wavelength into the preset standard curve and automatically converts it into the concentration value of the corresponding virus. After detection, the electromagnet 156, heating plate 159, rotating filter 31, electrochemical workstation 2, photon counting detector 32 and microcontroller control system are turned off, the microfluidic chip 1 is taken out, and the entire detection process is completed.

[0068] The entire detection process can be completed automatically through a microcontroller preset program without manual intervention. The total detection time is ≤20 minutes, enabling rapid on-site detection of viruses.

[0069] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0070] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A microfluidic detection device based on quantum dot luminescence, characterized in that, include: A microfluidic chip, comprising a microfluidic chip body, a sample liquid inlet, a sample chamber, a main channel, at least one branch channel, and at least one detection unit disposed on and connected in sequence to the microfluidic chip body; The detection unit includes a magnetic bead cavity, a mixing channel, a first inverted U-shaped channel, a detection cavity, and a second inverted U-shaped channel arranged sequentially along the fluid flow direction. An electromagnet is located on the back of the detection cavity. The detection cavity is connected to a three-electrode system. A reagent cavity is located above the detection cavity. A paraffin valve is located between the reagent cavity and the detection cavity. A heating element is located on the back of the paraffin valve. An electrochemical workstation, which is connected to the three-electrode system; At least one detection component, the detection component including a rotating filter and a photon counting detector, the rotating filter facing the front of the detection cavity and the photon counting detector facing the rotating filter.

2. The microfluidic detection device based on quantum dot luminescence according to claim 1, characterized in that, The outlet of the first inverted U-shaped flow channel is connected to the upper part of the detection cavity, and the top of the first inverted U-shaped flow channel is higher than the upper edge of the detection cavity.

3. The microfluidic detection device based on quantum dot luminescence according to claim 1, characterized in that, The inlet of the second inverted U-shaped flow channel is connected to the lower part of the detection cavity, and the top of the second inverted U-shaped flow channel is flush with the upper edge of the detection cavity.

4. A microfluidic detection device based on quantum dot luminescence according to claim 1 or 3, characterized in that, The outlet of the second inverted U-shaped flow channel is connected to a waste liquid chamber.

5. A microfluidic detection device based on quantum dot luminescence according to claim 4, characterized in that, The top of the waste liquid chamber is provided with an exhaust hole, and a breathable and waterproof membrane is provided at the exhaust hole.

6. A microfluidic detection device based on quantum dot luminescence according to claim 1, characterized in that, The sample chamber has an inverted pentagonal cavity structure.

7. A microfluidic detection device based on quantum dot luminescence according to claim 1, characterized in that, The mixing channel is a meandering mixing channel with a diameter of 400-800 μm.

8. A microfluidic detection device based on quantum dot luminescence according to claim 1, characterized in that, The number of the diversion channels and the detection units is two. Both diversion channels are connected to the main channel, and the two detection units are respectively connected to the two diversion channels.

9. A microfluidic detection device based on quantum dot luminescence according to claim 1, characterized in that, It also includes a support base, which is provided with a slot, at least one electromagnet and at least one heating element. At least one connector is provided in the slot. The microfluidic chip body is inserted into the slot. The electromagnet faces the back of the detection cavity and the heating element faces the back of the paraffin valve.

10. A microfluidic detection method, characterized in that, The microfluidic detection device based on quantum dot luminescence as described in any one of claims 1-9 includes the following steps: (1) Sample injection: The viral sample solution is injected into the sample chamber and diverted into the magnetic bead chamber of the detection unit under gravity. (2) Capture and enrichment: The freeze-dried nano magnetic beads powder in the magnetic bead cavity is incorporated into the virus sample liquid and enters the mixing channel. The virus combines with the nano magnetic beads to form a magnetic bead-virus complex, which flows into the detection cavity and is fixed by electromagnet adsorption. (3) Reagent release: Heating melts the paraffin valve, and the quantum dot probes and co-reactants pre-stored in the reagent chamber flow into the detection chamber under the action of gravity, and incubate to form a "magnetic bead-virus-quantum dot probe" sandwich complex; (4) Detection and analysis: The quantum dot electrochemiluminescence is excited by applying a constant potential through a three-electrode system. The luminescence signals of different wavelengths are collected sequentially by switching rotating filters and a photon counting detector to complete the quantitative detection of multiple viruses.

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