Microfluidic device and system for collecting a fluid sample

Abstract

This invention discloses a microfluidic device and system for collecting fluid samples, relating to the field of microfluidics technology. It includes a microfluidic chip, a first memory, and a detection component. The first memory comprises a first storage tube, a cap, a driving mechanism, and a second storage tube. The cap has a first inlet connected to a first outlet of the microfluidic chip. The driving mechanism is located on the cap. The second storage tube is connected to the driving mechanism and located inside the first storage tube. The detection component is configured to continuously detect whether a marker appears in the droplets of the fluid sample when the fluid sample flows from the first outlet of the microfluidic chip to the first inlet of the cap. If so, it controls the driving mechanism to move the second storage tube directly below the first inlet of the cap to collect the fluid sample. This invention can precisely control the timing of collecting marker fluid samples, minimizing the collection of impurity cells while conserving fluid sample, thus improving the purity of the target marker.

Description

Technical Field

[0001] This invention relates to the field of microfluidics, and in particular to a microfluidic device and system for collecting fluid samples. Background Technology

[0002] Specific biomarkers in human body fluids (such as blood) have become important evidence for researchers to discover and determine the progression of diseases. Circulating tumor cells (CTCs), as an important real-time tumor-specific biomarker present in the blood, play a crucial role in the early detection and monitoring of disease progression in cancer patients. However, the number of CTCs in the blood is extremely small compared to the large number of blood cells (10 white blood cells per milliliter of blood). 9 (The number of CTCs is 10-30). Therefore, it is necessary to effectively separate and purify specific biomarkers in blood to meet the requirements of downstream detection analysis or in vitro reculture analysis.

[0003] Microfluidics, as a technology for manipulating liquids at the micro- and nano-scale, has seen significant progress in the development of various microfluidic chips for the isolation of specific biomarkers such as CTCs.

[0004] However, the collection of biomarkers after separation by microfluidic chips in existing microfluidic technologies still has the following problems: it takes a period of time for the sample fluid flow rate to rise from zero to the set speed. During this process, the microfluidic channel cannot form a stable laminar flow state between the buffer solution and the original sample solution. If biomarker collection starts too early, more impurity cells will be collected, reducing the purity of the target biomarker. If biomarker collection starts too late, it will result in a great waste of sample solution. Summary of the Invention

[0005] This invention provides a microfluidic device and system for collecting fluid samples, which solves the technical problem that existing microfluidic devices for collecting fluid samples in the related art have difficulty in controlling the timing of starting to collect markers, resulting in a large number of impurity cells collected or waste of sample liquid.

[0006] In a first aspect, a microfluidic device for collecting fluid samples is provided, comprising: Microfluidic chips; The first memory includes: -First storage tube; - A cap is disposed on the opening of the first storage tube, and the cap is provided with a first inlet connected to the first outlet of the microfluidic chip; - A drive mechanism, which is disposed on the cap; - A second storage tube, which is connected to the drive mechanism and located inside the first storage tube; A detection component, located outside the first storage tube and electrically connected to the drive mechanism, is configured as follows: As the fluid sample flows from the first outlet of the microfluidic chip to the first inlet of the cap, the presence of markers in the droplets of the fluid sample is continuously detected. If so, the drive mechanism is controlled to move the second storage tube directly below the first inlet of the cap to collect the fluid sample.

[0007] In some embodiments, the continuous detection of whether a marker appears in the droplets of the fluid sample includes: Detect whether particles or cells within a preset size range are present in droplets of a fluid sample; If so, then the presence of a marker in the droplets of the fluid sample is confirmed.

[0008] In some embodiments, the drive mechanism includes: The first electromagnet and the second electromagnet are spaced apart on the cap. A slide rail is provided on the tube cap and located between the first electromagnet and the second electromagnet; A permanent magnet, which is disposed on the slide rail and can slide along the slide rail; The bracket has its upper end connected to the permanent magnet and its lower end supporting the second storage tube.

[0009] In some embodiments, the cap includes two first grooves and a second groove disposed between the two first grooves, the two first grooves being used to install the first electromagnet and the second electromagnet, and the second groove being used to install the slide rail.

[0010] In some embodiments, the detection component includes: A laser used to irradiate droplets of a fluid sample; A photodetector is used to convert received optical signals into electrical signals. The controller is electrically connected to the photodetector, the first electromagnet, and the second electromagnet.

[0011] In some embodiments, the photodetector is a photomultiplier tube.

[0012] In some embodiments, the microfluidic device for collecting fluid samples further includes: Three second memories, two of which are connected to the first inlet and the second inlet of the microfluidic chip, respectively, and the other second memory is connected to the second outlet of the microfluidic chip; A constant pressure gas source is connected to the first memory and three second memories.

[0013] In some embodiments, both the first and second storage tubes are made of polypropylene, and the caps are made of polytetrafluoroethylene, polyetheretherketone, or stainless steel.

[0014] In some embodiments, the microfluidic chip is an acoustic microfluidic chip, an inertial microfluidic chip, or a dielectrophoretic microfluidic chip.

[0015] Secondly, a microfluidic system for collecting fluid samples is provided, including the aforementioned microfluidic device for collecting fluid samples.

[0016] The beneficial effects of the technical solution provided by this invention include: This invention provides a microfluidic device and system for collecting fluid samples. The microfluidic device continuously detects droplets of fluid samples using a detection component. Once a marker appears in the droplet, the device controls a driving mechanism to move a second storage tube directly below the first inlet of the tube cap to collect the fluid sample. This precise timing of marker collection minimizes the collection of impurity cells while conserving fluid sample, thus improving the purity of the target marker. Furthermore, this invention employs a sheathed design for completely sealed collection of the marker sample, ensuring continuous sample collection and a sterile environment, providing effective support for subsequent downstream detection and analysis or in vitro reculture analysis. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a microfluidic device for collecting fluid samples provided in an embodiment of the present invention; Figure 2 A schematic diagram illustrating the operation of the drive structure of a microfluidic device for collecting fluid samples, provided in an embodiment of the present invention; Figure 3 A cross-sectional schematic diagram of the connection between the permanent magnet and the slide rail provided in an embodiment of the present invention; Figure 4 A schematic diagram of the connection between the permanent magnet and the support in the drive structure of a microfluidic device for collecting fluid samples, provided in an embodiment of the present invention; Figure 5 Provided for embodiments of the present invention Figure 4 Top view; Figure 6A schematic diagram of a microfluidic device for collecting fluid samples provided in an embodiment of the present invention; Figure 7 Another schematic diagram of a microfluidic device for collecting fluid samples provided in an embodiment of the present invention; Figure 8 A schematic diagram illustrating the different particle or cell motion states of a fluid sample in a microfluidic chip, provided in an embodiment of the present invention. Figure 9 Bright-field image of breast cancer cell lines provided in an embodiment of the present invention; Figure 10 This is a staining image of the viability of breast cancer cell lines provided in an embodiment of the present invention; Figure label: 1. Microfluidic chip; 2. First memory; 21. First memory tube; 22. Tube cap; 221. First groove; 222. Second groove; 23. Drive mechanism; 231. First electromagnet; 232. Second electromagnet; 233. Slide rail; 234. Permanent magnet; 235. Support; 236. Slider; 237. Adhesive plate; 238. Support top; 239. Test tube collar; 24. Second memory tube; 3. Detection components; 31. Laser; 32. Photodetector; 33. Controller; 4. Secondary memory; 5. Constant pressure air source. Detailed Implementation

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

[0020] This invention provides a microfluidic device for collecting fluid samples, which solves the technical problem that existing microfluidic devices for collecting fluid samples have difficulty in controlling the timing of starting to collect markers, resulting in a large number of impurity cells collected or waste of sample liquid.

[0021] See Figure 1 As shown, this embodiment of the invention provides a microfluidic device for collecting fluid samples, including: a microfluidic chip 1, a first memory 2, and a detection component 3.

[0022] The microfluidic chip 1 can be an acoustic microfluidic chip, an inertial microfluidic chip, or a dielectrophoretic microfluidic chip; in this embodiment, an acoustic microfluidic chip is actually used. The first memory 2 includes: a first storage tube 21, a cap 22, a driving mechanism 23, and a second storage tube 24. The cap 22 is disposed on the opening of the first storage tube 21, and the cap 22 has a first inlet connected to the first outlet of the microfluidic chip 1. The driving mechanism 23 is disposed on the cap 22, and the second storage tube 24 is connected to the driving mechanism 23 and located inside the first storage tube 21. Specifically, the first memory 2 is designed with two first storage tubes 21 and second storage tubes 24 of different capacities in a sheathed configuration, wherein the capacity of the first storage tube 21 is 50 mL, and the capacity of the second storage tube 24 is 1.5 mL. The first storage tube 21 can be a commercially available conical test tube with a diameter of 28.6 mm and a height of 121.4 mm, and the second storage tube 24 can be a commercially available conical test tube with a diameter of 10.8 mm and a height of 39.3 mm.

[0023] See Figure 1 and Figure 2 As shown, the detection component 3 is located outside the first storage tube 21 and electrically connected to the drive mechanism 23, and is configured as follows: When a fluid sample flows from the first outlet of the microfluidic chip 1 to the first inlet of the cap 22, the presence of markers in the droplets of the fluid sample is continuously detected. If so, the drive mechanism 23 is controlled to drive the second storage tube 24 to move directly below the first inlet of the cap 22 to collect fluid samples.

[0024] The microfluidic device for collecting fluid samples in this embodiment of the invention continuously detects droplets of fluid samples using a detection component. Once a marker appears in the droplet, the drive mechanism is controlled to move the second storage tube directly below the first inlet of the cap to collect the fluid sample. This precise timing of marker collection minimizes the collection of impurity cells while conserving fluid sample, thus improving the purity of the target marker. Furthermore, this embodiment employs a sheath design for completely sealed collection of the marker sample, ensuring continuous sample collection and a sterile environment, providing effective support for subsequent downstream detection and analysis or in vitro reculture analysis.

[0025] As an optional implementation, in one embodiment of the invention, the continuous detection of whether a marker appears in the droplets of the fluid sample includes: Detect whether particles or cells within a preset size range are present in the droplets of a fluid sample; If so, then the presence of a marker in the droplets of the fluid sample is confirmed.

[0026] Taking the sorting of breast cancer cells (markers) in a fluid sample as an example, the original fluid sample contains a large number of white blood cells (10T). 9 ( / mL) Due to the time lag in fluid flow rate stabilization during the initial stage, a large number of leukocytes will mix into the fluid sample droplets. If collected too early, the purity of breast cancer cells in the fluid sample will be reduced. The vast majority of leukocytes are smaller than 10 μm, while breast cancer cells are larger than 15 μm. The system detects whether particles or cells within a preset size range (greater than 15 μm) appear in the fluid sample droplets. If so, it is determined that breast cancer cells are present in the fluid sample droplets. At this time, the drive mechanism 23 is controlled to move the second storage tube 24 to directly below the first inlet of the cap 22 to collect the fluid sample, making the collection timing more precise.

[0027] As an optional implementation, in one embodiment of the invention, see [link to relevant documentation]. Figure 2 As shown, the driving mechanism 23 includes: a first electromagnet 231, a second electromagnet 232, a slide rail 233, a permanent magnet 234, and a bracket 235. The first electromagnet 231 and the second electromagnet 232 are spaced apart on the cap 22. The slide rail 233 is located on the cap 22 and between the first electromagnet 231 and the second electromagnet 232. The permanent magnet 234 is located on the slide rail 233 and can slide along it. The upper end of the bracket 235 is connected to the permanent magnet 234, and the lower end supports the second storage tube 24. The permanent magnet can be a neodymium magnet, a cube with a side length of 5mm. The slide rail 233 has a semi-enclosed structure for easy disassembly or replacement, and its lower base is a cuboid with a length, width, and thickness of 6mm. The first electromagnet 231 and the second electromagnet 232 can be ferrite cores with an outer diameter of 4mm and a height of 9mm. The support 235 includes a bent connecting rod and a circular bracket. The inner diameter of the circular bracket matches the opening size of a 1.5 mL test tube, and its characteristic inner diameter is 11 mm. The vertical height of the bent connecting rod is adapted to the height of the first storage tube 21 and the second storage tube 24. The characteristic vertical length of the bent connecting rod is 40-50 mm, and its characteristic horizontal length is 1-3 mm. See also... Figure 3 As shown, the permanent magnet 234 can be connected to a slider 236, and a slide rail 233 can be provided inside, allowing the slider 236 to slide on the slide rail. See also Figure 4 and Figure 5 As shown, the lower end of the permanent magnet 234 is bonded to the support top 238 at the upper end of the bracket 235 using a resin adhesive plate 237. That is, the second storage tube 24 is suspended inside the first storage tube 21 through the test tube collar 239 at the lower end of the bracket 235.

[0028] See Figure 2As shown, when the first electromagnet 231 is energized and the second electromagnet 232 is de-energized, the first electromagnet 231 generates a magnetic field that attracts the permanent magnet 234, causing the support 235 and the second storage tube 24 to move directly below the first inlet of the cap 22 to collect fluid samples. When the first electromagnet 231 is de-energized and the second electromagnet 232 is energized, the second electromagnet 232 generates a magnetic field that attracts the permanent magnet 234, causing the support 235 and the second storage tube 24 to move away from directly below the first inlet of the cap 22.

[0029] As an optional implementation, in one embodiment of the invention, the cap 22 includes two first grooves 221 and a second groove 222 disposed between the two first grooves 221. The two first grooves 221 are used to install the first electromagnet 231 and the second electromagnet 232, and the second groove 222 is used to install the slide rail 233. This design is simple in structure and easy to install. The two first grooves 221 are located on the upper outer surface of the cap 22, with a diameter of 5mm and a depth of 10mm, and the distance between the two first grooves 221 is 10mm. The second groove 222 is located on the inner surface of the cap 22, with a length of 8mm and a depth of 10mm.

[0030] As an optional implementation, in one embodiment of the invention, see [link to relevant documentation]. Figure 1 As shown, the detection component 3 includes a laser 31, a photodetector 32, and a controller 33. The photodetector 32 can be a photomultiplier tube; taking breast cancer cells as a marker as an example, the critical size for photomultiplier tube detection can be set to 15 μm. The wavelength of the laser 31 can be approximately 532 nm, and the photomultiplier tube is used for signal detection and feedback to the controller 33.

[0031] The laser 31 is used to irradiate the droplets of the fluid sample. The photodetector 32 is used to convert the received optical signal into an electrical signal. The controller 33 is electrically connected to the photodetector 32, the first electromagnet 231, and the second electromagnet 232. In the figure, the controller 33 has two signal output channels, CH1 and CH2. CH1 is connected to the first electromagnet 231, and CH2 is connected to the second electromagnet 232. The controller 33 can detect whether particles or cells within a preset size range appear in the droplets of the fluid sample based on the electrical signal converted by the photodetector 32. If no particles or cells within a preset size range are found in the droplets of the detected fluid sample, the controller 33 controls the first electromagnet 231 to be de-energized and the second electromagnet 232 to be energized. The second electromagnet 232 generates a magnetic field that attracts the permanent magnet 234, causing the support 235 and the second storage tube 24 to move away from directly below the first inlet of the cap 22.

[0032] If particles or cells within a preset size range are found in the droplets of the fluid sample, it is determined that a marker has appeared in the droplets of the fluid sample. When the controller 33 controls the first electromagnet 231 to be energized and the second electromagnet 232 to be de-energized, the first electromagnet 231 generates a magnetic field to attract the permanent magnet 234, which drives the support 235 and the second storage tube 24 to move directly below the first inlet of the cap 22 to collect the fluid sample.

[0033] As an optional implementation, in one embodiment of the invention, see [link to relevant documentation]. Figure 6 and Figure 7 As shown, the microfluidic device for collecting fluid samples further includes three second memories 4 and a constant pressure gas source 5. Two of the second memories 4 are connected to the first inlet and the second inlet of the microfluidic chip 1, respectively, and the other second memory 4 is connected to the second outlet of the microfluidic chip 1. The constant pressure gas source 5 is connected to the first memory 2 and the three second memories 4.

[0034] Specifically, see Figure 8As shown, the microfluidic chip 1 typically includes a first inlet A, a second inlet B, a first outlet C, and a second outlet D. The first inlet A is the raw sample liquid, the second inlet B is the buffer solution, the first outlet C is the marker sample liquid, and the second outlet D is the waste liquid. Specifically, one second memory 4 provides the raw sample liquid and is connected to the first inlet A; one second memory 4 provides the buffer solution and is connected to the second inlet B; one second memory 4 collects the waste liquid and is connected to the second outlet D; and the first inlet E of the first memory 2 (or the cap 22) collects the marker sample liquid and is connected to the first outlet C. The second inlet F of the first memory 2 is connected to the constant pressure air source 5. Similarly, the three second memory units 4 are connected to the constant pressure air source 5. The constant pressure air source 5 uses an air compressor to pressurize the air. After sterile filtration, the air pressure is stabilized by a high-speed electromagnetic gas valve. The air pressure of the constant pressure air source 5 can be set between 0.005-0.1 MPa to facilitate flow rate adjustment. The flow rate of the first outlet C is generally set to 300-500 μL / hr. The flow rates of other outlets can be set to a fixed flow rate ratio to ensure that the outlet liquid flows out in droplet form, which is beneficial for detection by the photodetector 32. In addition, the first inlet E of the first memory 2 uses a 1 / 16 Luer connector and a 1 / 16 capillary tube with an outer diameter of 1.58 mm and an inner diameter of 0.25 mm. The second inlet F of the first memory 2 (or the cap 22) uses a one-way quick-connect valve, and the air pipe interface size is 4 mm outer diameter. In this embodiment of the invention, the collected waste liquid can be recycled and processed again (because it is sealed and sterile, the original sample is almost undamaged) for reuse and purification.

[0035] See Figure 8 As shown, taking the sorting of breast cancer cells in a fluid sample as an example, when the fluid sample in the microfluidic chip 1 reaches a non-laminar steady state from zero to the target velocity, although cancer cells are being separated, the liquid at the sample outlet still contains a large number of white blood cells, such as... Figure 8 On the left, when the flow rate ratio between the two inlets of microfluidic chip 1 reaches a stable laminar flow state, due to the buffer sheath flow, white blood cells are squeezed out from waste liquid outlet C, and cancer cells flow out from the other outlet D, as shown. Figure 8 Right side. See also Figure 2As shown, in a non-laminar flow stable state, when the controller 33 controls the first electromagnet 231 to be de-energized and the second electromagnet 232 to be energized, the second electromagnet 232 generates a magnetic field that attracts the permanent magnet 234, causing the support 235 and the second storage tube 24 to move away from directly below the first inlet of the cap 22. When in a laminar flow stable state, when the controller 33 controls the first electromagnet 231 to be energized and the second electromagnet 232 to be de-energized, the first electromagnet 231 generates a magnetic field that attracts the permanent magnet 234, causing the support 235 and the second storage tube 24 to move directly below the first inlet of the cap 22 to collect fluid samples. See also... Figure 9 and Figure 10 As shown, the breast cancer cells in the sample were collected by the microfluidic device of this embodiment of the invention, and the breast cancer cells in the sample maintained good viable morphology. Figure 9 Bright field image of breast cancer cell lines. Figure 10 This is a staining image of viability of breast cancer cell lines. Figure 9 Bright-field images of breast cancer cell lines can demonstrate that breast cancer cells have an intact external structure. Figure 10 Viability staining of breast cancer cell lines can demonstrate that breast cancer cells are viable and capable of being recultured and analyzed further.

[0036] The embodiments of the present invention are not limited to the collection of a single sample fluid target. Multiple second storage tubes 24 can be connected in parallel in the first storage tube 21 to separate three different sizes of cells, such as platelets, white blood cells and cancer cells, so as to achieve separate collection of white blood cells and cancer cells and reduce the impact of platelet cells on purity.

[0037] As an optional implementation, in one embodiment of the invention, both the first storage tube 21 and the second storage tube 24 are made of polypropylene (PP), and the tube cap 22 is made of polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), or stainless steel. The above materials have good biocompatibility and can be repeatedly sterilized at high temperatures.

[0038] This invention also provides a microfluidic system for collecting fluid samples, including the aforementioned microfluidic device for collecting fluid samples.

[0039] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" 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; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0040] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0041] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A microfluidic device for collecting fluid samples, characterized in that, include: Microfluidic chip (1); The first memory (2) includes: -First storage tube (21); - A cap (22) is provided on the opening of the first storage tube (21), and the cap (22) is provided with a first inlet connected to the first outlet of the microfluidic chip (1); - Drive mechanism (23), which is disposed on the cap (22); - A second storage tube (24), which is connected to the drive mechanism (23) and located inside the first storage tube (21); The detection component (3), which is located outside the first storage tube (21) and electrically connected to the drive mechanism (23), is configured as follows: When a fluid sample flows from the first outlet of the microfluidic chip (1) to the first inlet of the cap (22), the presence of markers in the droplets of the fluid sample is continuously detected. If so, the drive mechanism (23) is controlled to drive the second storage tube (24) to move directly below the first inlet of the cap (22) to collect fluid samples.

2. The microfluidic device for collecting fluid samples according to claim 1, characterized in that, The continuous detection of whether markers appear in droplets of the fluid sample includes: Detect whether particles or cells within a preset size range are present in droplets of a fluid sample; If so, then the presence of a marker in the droplets of the fluid sample is confirmed.

3. The microfluidic device for collecting fluid samples according to claim 1, characterized in that, The drive mechanism (23) includes: The first electromagnet (231) and the second electromagnet (232) are spaced apart on the cap (22); A slide rail (233) is provided on the cap (22) and located between the first electromagnet (231) and the second electromagnet (232); A permanent magnet (234) is disposed on the slide rail (233) and can slide along the slide rail (233); The bracket (235) is connected at its upper end to the permanent magnet (234) and at its lower end to support the second storage tube (24).

4. The microfluidic device for collecting fluid samples according to claim 3, characterized in that: The cap (22) includes two first grooves (221) and a second groove (222) located between the two first grooves (221). The two first grooves (221) are used to install the first electromagnet (231) and the second electromagnet (232), and the second groove (222) is used to install the slide rail (233).

5. The microfluidic device for collecting fluid samples according to claim 3, characterized in that, The detection component (3) includes: A laser (31) is used to irradiate droplets of a fluid sample; A photodetector (32) is used to convert received optical signals into electrical signals; The controller (33) is electrically connected to the photodetector (32), the first electromagnet (231) and the second electromagnet (232).

6. The microfluidic device for collecting fluid samples according to claim 5, characterized in that: The photodetector (32) is a photomultiplier tube.

7. The microfluidic device for collecting fluid samples according to claim 1, characterized in that, Also includes: Three second memories (4), two of which are connected to the first inlet and the second inlet of the microfluidic chip (1) respectively, and the other second memory (4) is connected to the second outlet of the microfluidic chip (1); A constant pressure gas source (5) is connected to the first memory (2) and three second memories (4).

8. The microfluidic device for collecting fluid samples according to claim 7, characterized in that: The first storage tube (21) and the second storage tube (24) are both made of polypropylene, and the tube cap (22) is made of polytetrafluoroethylene, polyetheretherketone or stainless steel.

9. The microfluidic device for collecting fluid samples according to claim 1, characterized in that: The microfluidic chip (1) is an acoustic microfluidic chip, an inertial microfluidic chip, or a dielectrophoretic microfluidic chip.

10. A microfluidic system for collecting fluid samples, characterized in that, The microfluidic device for collecting fluid samples as described in any one of claims 1-9.

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