Microfluidic chip and detection device based on optically enhanced detection of dielectric microsphere arrays

Abstract

The present invention discloses a microfluidic chip based on optically enhanced detection of a dielectric microsphere array, comprising a chip body, wherein the chip body comprises an upper cover plate, a flow channel layer, and a bottom plate layer stacked in sequence; a dielectric microsphere array is embedded on the contact surface between the upper cover plate and the flow channel layer, capable of focusing incident excitation light and refracting the excited optical signal to the outside of the upper cover plate; the portion of the dielectric microsphere array exposed from the upper cover plate is specifically modified; an injection port, a liquid outlet, and a detection area are provided on the contact surface between the flow channel layer and the upper cover plate, the detection area is connected to the injection port and the liquid outlet, and the detection area is in direct contact with the portion of the dielectric microsphere array exposed from the upper cover plate. The present invention also discloses a microfluidic detection device. The present invention achieves antibody coating by specifically modifying the exposed surface of the dielectric microsphere array, and the object to be detected is captured on the surface of the exposed microspheres through the combination of antigen and antibody, thereby enriching the object and greatly improving the sensitivity and resolution of optical detection.

Description

Technical Field

[0001] The present invention relates to an optical detection chip and device, in particular to a microfluidic chip and a detection device based on optically enhanced detection of a dielectric microsphere array. Background Art

[0002] Optical signal detection can be categorized into fluorescence and Raman spectroscopy. Fluorescence is the light emitted by a substance after absorbing light or other electromagnetic radiation, and it has extensive applications in biochemistry and medicine. Fluorescent chemical groups can be attached to biomacromolecules through chemical reactions, and the fluorescence emitted by the tracer groups can then be observed to sensitively detect these biomacromolecules. Raman spectroscopy is a spectroscopic method for studying molecular vibrations and rotations. It is a specific spectrum produced by the inelastic scattering of excitation light by the analyte. Known as the "fingerprint" of a substance, Raman spectroscopy can be used to study molecular structural information and has excellent detection specificity. It also has the advantages of short detection times, non-contact with the sample, and the ability to simultaneously and qualitatively and quantitatively detect a variety of liquids, gases, and solids. Optical signal detection technology has rapidly developed and has found widespread application in fields such as materials analysis, biomedicine, and petrochemicals, providing a powerful research method for the development of various disciplines.

[0003] Microfluidics refers to the science and technology involved in systems that use microchannels to process or manipulate tiny fluids. It integrates complex processing flows and plays a vital role in fields such as organic synthesis, microreactors, chemical analysis, and biomedicine. Microfluidics often require optical detection methods, and their combination with optical detection technology holds great potential and development prospects.

[0004] Protein microarrays are a high-throughput technology for analyzing protein function. The principle is to subject a solid-phase carrier (glass slides, silicon, etc.) to a special chemical treatment, then immobilize known protein molecule products (antibodies, etc.) onto them. Based on the properties of these biomolecules, the test proteins (antigens, etc.) that specifically bind to them are captured. After washing and purification, confirmation and biochemical analysis are performed. Its detection method is to label the test protein with fluorescent dye or isotopes. Proteins bound to the chip will emit a specific signal, which is recorded with a camera during detection and analyzed using computer software. Currently, research on high-sensitivity and high-resolution detection methods and the integration of imaging and data analysis remain the focus of future development.

[0005] Currently, fluorescence detection often requires very high detection sensitivity, which requires that optical signals can still be detected at very low fluorescence signal intensities. Similarly, in Raman spectroscopy detection, the intensity of Raman scattered light is very low, resulting in low sensitivity in detection, which greatly limits the application of Raman spectroscopy. In addition, the mainstream mature Raman detection spectrometers have a short working distance and the focus position requires precise positioning, which also hinders the integration of Raman spectroscopy methods. This makes it difficult to apply optical detection technology in integrated microfluidic systems. In the field of protein chips, the use of glass slides as carriers for optical signal detection often does not meet the required sensitivity and resolution. This requires the search for a micro-nanostructure that can enhance optical signals. Summary of the Invention

[0006] Purpose of the invention: In order to overcome the deficiencies in the prior art, the purpose of the present invention is to provide a microfluidic chip based on dielectric microsphere array optical enhanced detection with enhanced optical detection sensitivity and good signal stability. Another purpose of the present invention is to provide a microfluidic detection device that significantly improves the optical signal intensity.

[0007] Technical solution: The microfluidic chip based on optically enhanced detection of dielectric microsphere arrays described in the present invention includes a chip body, which includes an upper cover plate, a flow channel layer and a bottom plate layer stacked in sequence; the dielectric microsphere array is embedded on the contact surface between the upper cover plate and the flow channel layer, which can focus the incident excitation light and refract the excited optical signal to the outside of the upper cover plate; the portion of the dielectric microsphere array exposed from the upper cover plate is specifically modified to achieve antibody coating, and the objects to be detected (antigens, exosomes, cells) can be captured on the surface of the leaked microspheres through the combination of antigens and antibodies; an injection port, a liquid outlet, and a detection area are provided on the contact surface between the flow channel layer and the upper cover plate, and the detection area is connected to the injection port and the liquid outlet, and the detection area is in direct contact with the portion of the dielectric microsphere array exposed from the upper cover plate.

[0008] Furthermore, the dielectric microsphere array is embedded in the upper cover plate to a depth of 0.3 to 1.0 times the diameter of the dielectric microspheres. The dielectric microspheres have a higher refractive index and melting temperature than the upper cover plate, and a diameter of 300 μm or less. The dielectric microspheres are preferably BaTiO3 microspheres or doped high-refractive-index glass microspheres.

[0009] Furthermore, the excitation light is a convergent light beam or a parallel light beam, and the angle between the excitation light and the upper cover plate is 30 degrees to 150 degrees.

[0010] The upper cover plate should be highly transparent within the fluorescence spectrum range and have a low melting temperature. The upper cover plate is made of PMMA, PC, PMDS or PP material, and the dielectric microsphere array is embedded in the upper cover plate by hot pressing.

[0011] Furthermore, the flow channel layer for detecting optical signals is an acrylic plate with a thickness of more than 0.1 mm.

[0012] In order to avoid interference and reduce the impact on detection data, the bottom plate layer is quartz glass or silicon wafer.

[0013] Furthermore, a comparison area is provided on the contact surface between the flow channel layer and the upper cover plate for comparing the enhancement effect of the dielectric microsphere array, and the comparison area is connected to the liquid injection port and the liquid outlet.

[0014] The microfluidic detection device described in the present invention includes a chip body, a probe, an expansion structure and an optical lens; the chip body includes an upper cover plate, a flow channel layer and a bottom plate layer stacked in sequence; a dielectric microsphere array is embedded on the contact surface between the upper cover plate and the flow channel layer, which can focus incident excitation light and refract the excited optical signal to the outside of the upper cover plate; the portion of the dielectric microsphere array exposed from the upper cover plate is specifically modified; an injection port, a liquid outlet and a detection area are provided on the contact surface between the flow channel layer and the upper cover plate, the detection area is connected to the injection port and the liquid outlet, and the detection area is in direct contact with the portion of the dielectric microsphere array exposed from the upper cover plate; the expansion structure is connected to the probe and can adjust and fix the optical lens; the optical lens is coaxial with the probe, and the focus of the optical lens coincides with the focus of the outgoing light beam of the probe's excitation light, so that the outgoing light beam of the optical lens becomes nearly parallel light, greatly increasing the working distance.

[0015] Furthermore, the excited optical signal is a fluorescence signal, a Raman spectrum signal or a chemiluminescence signal. The distance from the bottom of the extended structure to the upper surface of the chip body is not affected by distance and angle.

[0016] Working Principle: The excitation light from a conventional detector probe is first converted into parallel light through a lens, increasing the working distance. The focusing enhancement effect of a dielectric microsphere array is then utilized to focus the parallel light emitted by the lens into the detection chamber of a microfluidic chip, multiplying the spectral signal intensity. The microsphere array is designed to be embedded under the upper cover of the microfluidic chip's detection chamber, achieving on-chip detection integration. The microspheres are specifically modified in the portion exposed under the upper cover, allowing for specific binding, capture, and enrichment of the detection substance, thereby enhancing sensitivity.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following significant features:

[0018] 1. By specifically modifying the exposed surface of the medium microsphere array to achieve antibody coating, the objects to be detected (antigens, exosomes, cells) can be captured on the surface of the leaked microspheres through the combination of antigen and antibody, which plays an enrichment role and greatly improves the sensitivity of optical detection;

[0019] 2. The dielectric microsphere array with good focusing effect is integrated into the microfluidic chip. The process flow is complete and the sealing is good, which is very convenient for integrated detection chip.

[0020] 3. Combining optical signal detection technology with microfluidics technology, by expanding the structure, the focused light beam emitted by the spectrometer is converted into parallel light, increasing the working distance and stability. Under the irradiation of parallel excitation light, the light beam is focused in the detection cavity through the microsphere, thereby obtaining a stronger optical signal. This method has a good optical signal enhancement effect at different distances and angles and has extremely high stability.

[0021] 4. The output light beam of the detector after passing through the lens is parallel light, which is conducive to expanding the working distance and there is no need to consider the focusing problem of the light beam. The dielectric microsphere array is integrated on the microfluidic detection chip. Through the convergence effect of the dielectric microsphere array, the detection beam is accurately focused on the position of the molecule to be measured, avoiding complex focusing and alignment operations. It is easy to use and is a highly promising long-distance, contactless detection method. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention;

[0023] Figure 2 is a perspective view of the expanded structure 3 of the present invention;

[0024] Figure 3 is a top view of the chip body 1 of the present invention;

[0025] Figure 4 It is a left perspective view of the upper cover plate 11 of the present invention;

[0026] Figure 5 Schematic diagram of the optical path of the dielectric microsphere array 14 of the present invention;

[0027] Figure 6 is a diagram showing the working principle of the dielectric microsphere array 14 of the present invention;

[0028] Figure 7 is a microscopic image of the dielectric microsphere array 14 of the present invention;

[0029] Figure 8 is a top view of the flow channel layer 12 of the present invention;

[0030] Figure 9 is a Raman scattering spectrum diagram at different distances of the present invention;

[0031] Figure 10 This is a comparison diagram of the enhancement effect of the present invention at different distances;

[0032] Figure 11 is a Raman scattering spectrum diagram under the deflection angle of the present invention;

[0033] Figure 12 This is a comparison diagram of the enhancement effect under the deflection angle of the present invention. DETAILED DESCRIPTION

[0034] like Figure 1 The expansion structure 3 of the microfluidic detection device is fixedly connected to the probe 2 by threads. Both are made by 3D printing and are made of ABS thermoplastic engineering plastic. The expansion structure 3 can adjust and fix the optical lens 4. The optical lens 4 is coaxial with the probe 2 and the outgoing light beam of the detector. The focus of the optical lens 4 coincides with the focus of the outgoing light beam of the excitation light of the probe 2, so that the outgoing light beam becomes nearly parallel light. The optical lens 4 has a focal length of 3mm and is made of K9 crystal material. The chip body 1 includes an upper cover plate 11, a flow channel layer 12 and a bottom plate layer 13 from top to bottom. The layers are bonded and fixed by double-sided tape with good sealing properties. The flow channel layer 12 is made of acrylic plate with a thickness of more than 0.1mm. The bottom plate layer 13 is made of quartz glass or silicon wafer.

[0035] like Figure 2 The extended structure 3 includes a first column 31 and a second column 32, which can be fixed on the probe 2. The side wall of the first column 31 has a threaded hole 33, and the side wall of the second column 32 has two threaded holes 33, which can be fixed and adjusted in position. The matching slots 34 on the first column 31 and the second column 32 can fix the optical lens 4 by tightening the screws. The outgoing beam of the excitation light of the detector will be converted into nearly parallel light through the optical lens 4, and the specific position of the optical lens 44 can be determined by adjusting the position of the extended structure 3. The parallel light emitted from the extended structure 2 is irradiated on the dielectric microsphere array 14, and is focused again in the detection area 123 through the dielectric microsphere array 14 to achieve optical signal measurement of the target to be measured.

[0036] like Figures 3 to 7A dielectric microsphere array 14 is embedded on the contact surface between the upper cover plate 11 and the flow channel layer 12, with an embedding depth of 0.3 to 1.0 times the diameter of the dielectric microspheres. The dielectric microspheres have a higher refractive index and melting temperature than the upper cover plate, and a diameter of 300 μm or less. The dielectric microspheres are preferably BaTiO3 microspheres or high-refractive-index glass microspheres, such as ZBLAN glass microspheres doped with Ho3+ ions, with a diameter of 180 to 220 μm. The dielectric microspheres have a higher refractive index than the upper cover plate 11, and a higher melting temperature than the upper cover plate 11. The outgoing light beam from the optical lens 4, incident from the outside of the upper cover plate 11, is focused on the detection area 123 within the flow channel layer 12. The optical signal excited by the outgoing light beam is refracted by the dielectric microsphere array 14 and propagates to the outside of the upper cover plate 11. The outgoing light beam from the optical lens 4 is a convergent light beam or a parallel light beam, and the angle between the outgoing light beam from the optical lens 4 and the upper cover plate 11 is 30 to 150 degrees. The excited optical signal is a fluorescence signal, a Raman spectrum signal or a chemiluminescence signal. The material of the upper cover 11 needs to have a low melting temperature, and the upper cover 11 needs to be highly transparent within the fluorescence spectrum range, so the material selected is organic glass (PMMA, PC, PMDS or PP). The portion of the dielectric microsphere array 14 that is exposed from the upper cover 11 is specifically modified to achieve antibody coating, and the objects to be detected (antigens, exosomes, cells) can be captured on the surface of the leaked microspheres through the combination of antigens and antibodies. The shape of the limiting boundary of the dielectric microsphere array 14 is consistent with the shape of the detection area of ​​the chip body 1.

[0037] The dielectric microsphere array 14 is embedded into the upper cover plate 11 by hot pressing, which specifically includes the following steps:

[0038] S1. Laser-cut an acrylic sheet into a square shape with a thickness of 1.1 to 2 times the diameter of the microspheres. This is used to shape the microsphere array, facilitating the fixation of the dielectric microsphere array 14, further reducing detection errors. This ensures uniqueness of variables when comparing enhancement effects, improving the stability of the method. It also shapes the upper cover plate 11, smoothing the top surface of the film and reducing detection errors. After cutting, the surface remains clean and flat, facilitating subsequent direct splicing onto the top surface of the microfluidic chip.

[0039] S2. Prepare a thin film with a circular center cut out to define the area for the dielectric microsphere array 14. This film is made of quartz glass and has a thickness of 0 to 0.6 times the diameter of the microspheres. The circular shape matches the shape of the detection area 123, and the circular boundary also facilitates the self-assembly of the dielectric microsphere array 14.

[0040] S3, then you need to prepare a clean base plate for film preparation, use a clean 10mm thick quartz glass plate as the base plate and wipe it clean with alcohol.

[0041] S4. Clean the surface of the acrylic plate and the thin film with alcohol to avoid protrusions caused by dust particles when connecting with double-sided tape. Use a thin and well-sealed UV adhesive to stick the thin film to the base plate. Stick a layer of double-sided tape on the bottom surface of the acrylic plate to facilitate subsequent connection with other parts of the microfluidic chip. Press the pasted base plate tightly for 10 hours to ensure tight adhesion.

[0042] In step S5, 10 mg of dielectric microspheres with a diameter of 180-220 μm are mixed with 200 μl of water and placed under ultrasound for 5 minutes. The mixture is then dropped onto the shaped area of ​​dielectric microsphere array 14. The entire structure is placed in an oven at 75°C until completely dried, and then removed. During the evaporation of the liquid, dielectric microsphere array 14 self-assembles due to surface tension.

[0043] S6, place the entire structure horizontally and fix it, align the unadhesive surface of the acrylic plate and attach it to the sheet, and place the entire structure into a vacuum bag to maintain vacuum.

[0044] S7, the whole structure is placed in a vacuum oven. In order to make the upper surface of the prepared film flat, it needs to be kept horizontal and fixed at 160°C. Continuous pressure needs to be applied on the acrylic plate. For about 1 hour, most of the microsphere array is embedded. After it is slowly cooled, it is taken out.

[0045] S8, after the complete upper cover plate 11 is formed, slowly tear off the upper cover plate 11 to obtain the upper cover plate 11 with the dielectric microsphere array 14.

[0046] At this point, the upper cover plate 11 with the dielectric microsphere array 14 and double-sided tape on the bottom is completed and can be directly integrated on the upper surface of the microfluidic chip.

[0047] The subsequent preparation process of the chip body 1 includes the following steps:

[0048] S1, the upper cover plate 11 of the chip body 1 has been manufactured, and the middle flow channel layer 12 is manufactured by laser cutting. It is divided into a liquid injection 121, a liquid outlet 122, a flow channel, a detection area 123, and a comparison area 124. The thickness is more than 0.1 mm and the material is an acrylic plate.

[0049] S2, the bottom plate layer 13 is made of quartz glass to minimize the impact on the test data. The three-layer package is adhered using double-sided tape and pressed for 12 hours to complete the overall package.

[0050] like Figure 8The contact surface between the flow channel layer 12 and the upper cover plate 11 is provided with a liquid injection port 121, a liquid outlet 122, a detection area 123, and a comparison area 124. The detection area 123 and the comparison area 124 are both connected to the liquid injection port 121 and the liquid outlet 122 via pipes. The detection area 123 is in direct contact with the portion of the dielectric microsphere array 14 exposed from the upper cover plate 11.

[0051] The method for using the microfluidic detection device specifically includes the following steps:

[0052] a. Use a syringe to draw the sample solution to be tested, install it on the syringe pump, and fix and seal it with the capillary hose of the injection port 121;

[0053] b. Turn on the syringe pump and push the test liquid into the chip body 1 at a speed of 50 μL / min. After a certain period of time, when the test liquid reaches the detection area 123 and the comparison area 124, stop the syringe pump;

[0054] c. Turn on the spectrometer, aim the parallel light at the detection area 123 and the comparison area 124, and select the appropriate excitation light intensity and integration time;

[0055] d. After collecting the spectral data, turn off the spectrometer, replace the syringe with pure water, and push it in at a speed of 100 μL / min to complete the flushing of the chip body 1. Then, the next detection experiment can be carried out.

[0056] Test 1

[0057] In order to further explore the effects of working distance and angle and demonstrate the unique advantages of the present invention, ethanol was used as the experimental object to explore the effect of working distance on optical signal intensity.

[0058] The specific experimental steps are as follows: ethanol is injected from the injection port through the push of the syringe pump at a speed of 50 μL / min. After the ethanol fills the detection cavity area 123, the spectrometer is turned on, the laser power is selected to 36.5 W, the integration time is 10 s, and multiple sets of spectral signal data are collected.

[0059] Adjust the working distance and repeat the above steps. To determine the enhancement effect at different working distances, the spectral signal enhancement effect at working distances (from the extended structure 2 to the upper surface of the chip body 1) of 10mm, 20mm, 30mm, 40mm, and 50mm was investigated. -1 The characteristic peak at the bottom is used as the comparison target to compare the enhancement factor under the microsphere condition. The results are as follows Figures 9-10 As shown in the figure, in the 10-50mm area, there is a stable enhancement effect of about 6 times.

[0060] Testing the enhancement effect at different distances revealed that the spectral signal enhancement factor exhibited a stable fluctuation trend. In this invention's detection device, the lens's output beam is nearly parallel. From a geometric optics perspective, the spot size and position of the parallel light irradiating the microsphere array surface remain unchanged at longer working distances. It is predicted that a stable enhancement effect of approximately 6x will be achieved even at working distances greater than 50 mm.

[0061] Test 2

[0062] Using ethanol as the experimental subject, the effect of angle on optical signal intensity was investigated. Further verification of the enhancement effect at different angles was conducted, and the optical signal enhancement factor was investigated from 0° to 30°.

[0063] The specific experimental steps are as follows: ethanol is injected from the injection port through the push of the syringe pump at a speed of 50ul / min. After the ethanol fills the detection area 123, the spectrometer is turned on, the laser power is selected to 36.5W, the integration time is 10s, and multiple sets of spectral signal data are collected. After completing data collection, rinse with pure water.

[0064] Adjust the angle of the probe 2, change the angle between the incident light beam and the horizontal plane, and repeat the above steps. Here, the specific deflection angle is determined by measuring the horizontal and vertical distances of the light spot formed by the outgoing light beam of the optical lens 4 on the upper surface of the chip body 1. The arc tangent of the ratio of the two is the specific angle. It is verified that when the deflection angle is 0° to 30°, the ethanol 880cm -1 The characteristic peak at is the comparison target, such as Figures 11-12 As shown, there is a stable enhancement effect of about 6 times.

[0065] Testing the enhancement effect at different angles revealed that the spectral signal enhancement factor exhibited a stable, fluctuating trend. In this invention's detection device, the output beam from the lens is nearly parallel. From a geometric optics perspective, the focal position of parallel light after being focused by the microsphere array shifts with the operating angle, but the relative position of the focus to the microspheres and the quality of the focus remain unchanged. It is predicted that a stable enhancement effect of approximately 6x will be achieved even at operating angles of 30° to 60°.

Claims

1. A microfluidic chip based on dielectric microsphere array optically enhanced detection, characterized by: The invention comprises a chip body (1), wherein the chip body (1) comprises an upper cover plate (11), a flow channel layer (12) and a bottom plate layer (13) stacked in sequence; a dielectric microsphere array (14) is embedded on the contact surface between the upper cover plate (11) and the flow channel layer (12), and is capable of focusing incident excitation light and refracting the excited optical signal to the outside of the upper cover plate (11); a portion of the dielectric microsphere array (14) exposed from the upper cover plate (11) is specifically modified; a liquid injection port (121), a liquid outlet (122) and a detection area (123) are provided on the contact surface between the flow channel layer (12) and the upper cover plate (11); the detection area (123) is connected to the liquid injection port (121) and the liquid outlet (122), and the detection area (123) is in direct contact with the portion of the dielectric microsphere array (14) exposed from the upper cover plate (11).

2. The microfluidic chip based on dielectric microsphere array optical enhanced detection according to claim 1, characterized in that: The depth of the dielectric microsphere array (14) embedded in the upper cover plate (11) is 0.3 to 1.0 times the diameter of the dielectric microspheres.

3. The microfluidic chip based on dielectric microsphere array optical enhanced detection according to claim 1, characterized in that: The refractive index and melting temperature of the dielectric microspheres are higher than those of the upper cover plate (11), and the diameter is less than or equal to 300 μm.

4. The microfluidic chip based on dielectric microsphere array optical enhanced detection according to claim 1, characterized in that: The excitation light is a convergent light beam or a parallel light beam, and the angle between the excitation light and the upper cover plate (11) is 30 degrees to 150 degrees.

5. The microfluidic chip based on dielectric microsphere array optical enhanced detection according to claim 1, characterized in that: The upper cover plate (11) is made of PMMA, PC, PMDS or PP material, and the dielectric microsphere array (14) is embedded in the upper cover plate (11) by hot pressing.

6. The microfluidic chip based on dielectric microsphere array optical enhanced detection according to claim 1, characterized in that: The flow channel layer (12) is an acrylic plate with a thickness greater than or equal to 0.1 mm.

7. The microfluidic chip based on dielectric microsphere array optical enhanced detection according to claim 1, characterized in that: The bottom plate layer (13) is quartz glass or silicon wafer.

8. The microfluidic chip based on dielectric microsphere array optically enhanced detection according to claim 1, characterized in that: A contrast area (124) is further provided on the contact surface between the flow channel layer (12) and the upper cover plate (11), and the contrast area (124) is connected to the liquid injection port (121) and the liquid outlet (122).

9. A microfluidic detection device, characterized in that: The invention comprises a chip body (1), a probe (2), an expansion structure (3) and an optical lens (4); the chip body (1) comprises an upper cover plate (11), a flow channel layer (12) and a bottom plate layer (13) stacked in sequence; a dielectric microsphere array (14) is embedded on the contact surface between the upper cover plate (11) and the flow channel layer (12), which can focus the incident excitation light and refract the excited optical signal to the outside of the upper cover plate (11); the portion of the dielectric microsphere array (14) exposed from the upper cover plate (11) is specifically modified; the flow channel layer (12) and the upper cover plate (13) are connected to each other. 1), a liquid injection port (121), a liquid outlet (122), and a detection area (123) are provided on the contact surface of the probe (1); the detection area (123) is connected to the liquid injection port (121) and the liquid outlet (122); the detection area (123) is in direct contact with the portion of the dielectric microsphere array (14) exposed from the upper cover plate (11); the expansion structure (3) is connected to the probe (2) and can adjust and fix the optical lens (4); the optical lens (4) is coaxial with the probe (2), and the focus of the optical lens (4) coincides with the focus of the outgoing beam of the excitation light of the probe (2).

10. The microfluidic detection device according to claim 9, characterized in that: The excited optical signal is a fluorescence signal, a Raman spectrum signal or a chemiluminescence signal.

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