Dean flow sorting device and method for on-line quantitative detection of cow's milk somatic cells

Abstract

The invention discloses a Dean flow sorting device and method for on-line quantitative detection of cow's milk somatic cells, and belongs to the technical field of microfluidic cell detection. The device comprises a real-time cow milk sample collection unit, a sample inlet throttle valve, a Den flow micro-fluidic chip, a somatic cell enrichment milk sample outlet throttle valve, a somatic cell deficiency milk sample outlet throttle valve, an enrichment sample impedance detection unit, a deficiency sample impedance detection unit, a data processing unit and an online display unit. Interference suppression is realized by utilizing a sorting function of a Den flow micro-fluidic chip, somatic cells in cow milk are separated from other components, interference of complex conditions such as ion components in cow milk, environment temperature and the like on impedance data is effectively eliminated through comparative detection of somatic cell enrichment samples and somatic cell deletion samples, and the accuracy of a detection result is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of microfluidic cell detection, and relates to a Dean flow sorting device and method for online quantitative detection of bovine milk somatic cells. Background Art

[0002] High-quality raw milk is the first link to ensure the quality and safety of dairy products. It is very important to maintain the health of dairy cows at the source and reduce the occurrence of dairy cow diseases. Mastitis is the disease with the highest incidence in dairy cows. Subclinical mastitis has no obvious symptoms and is difficult to detect, which can easily cause the disease to spread in the herd, resulting in a decrease in milk production and a significant reduction in milk quality. The key to reducing its harm is to quickly and accurately detect sick cows with subclinical mastitis and take corresponding measures. Somatic cell count is a direct and accurate detection indicator in the diagnosis of dairy cow mastitis.

[0003] The detection methods of somatic cell count can be divided into direct method and indirect method. Among them, the direct method refers to the detection and identification of individual somatic cells one by one to achieve the purpose of counting, which mainly includes microscope counting method, Coulter counting method and fluorescence photoelectric counting method. The microscope method directly counts the somatic cells in bovine milk through somatic cell staining smears and microscope observation. Its detection accuracy is high, but it relies on manual observation and judgment, and the detection takes a long time. The Coulter counting method, also known as the electric pulse cell counting method, detects the somatic cell count by reading the voltage pulses generated when the somatic cells pass through the electrode slit. It requires a long time for instrument calibration and sample processing. The fluorescence photoelectric counting method is flow cytometry. Its principle is that the fluorescently stained cell nucleus produces fluorescence under the excitation of the laser, and the photoelectric pulse signal is used to count the somatic cells. This method also requires a time-consuming staining process.

[0004] Indirect detection methods collect relevant physical and chemical characteristic parameters of somatic cell mixtures and then estimate the number of somatic cells. They mainly include viscosity method, electrochemical method, and electrical impedance method. The detection principle of viscosity method or California Mastitis Test (CMT) is that under the action of surfactants or alkaline substances, somatic cells are lysed to release DNA and produce precipitation or gel. The range of somatic cells is indirectly determined according to the change in milk viscosity. Additional chemical reaction reagents are required, and the correlation between viscosity change and somatic cell count is not high enough, so the detection accuracy is low. The electrochemical method mainly detects the concentration of dissolved oxygen in milk by electrochemical reaction on platinum electrodes based on the consumption of oxygen in milk by cellular respiration, and then indirectly detects the concentration of somatic cells. However, since the concentration of dissolved oxygen in milk is greatly affected by other factors, the accuracy of the electrochemical method is also low. The electrical impedance method of somatic cell detection includes the conductivity method and the dielectric constant method / capacitance method. It is based on the detection of electrical parameters such as the electrical impedance (i.e., conductivity and dielectric constant / capacitance) of cow's milk. The principle is that due to the phospholipid bilayer membrane structure of somatic cells, the presence of somatic cells reduces the conductivity of cow's milk and increases the permittivity. The electrical impedance method has the advantages of not requiring supporting reagents, fast detection speed, and real-time detection. Summary of the invention

[0005] Among the main bovine milk somatic cell detection methods currently available, direct somatic cell counting methods based on microscopic imaging, fluorescence photoelectricity, Coulter counting, etc. have high quantitative accuracy, but require complex and time-consuming sample preprocessing, making it difficult to achieve online detection of somatic cells, and are mainly used for offline detection with regular sampling.

[0006] The indirect detection method based on the detection of other physical and chemical parameters related to the somatic cell count (mainly electrical parameters, namely electrical impedance) and the estimation of the somatic cell count has a fast detection speed and has become the main method for online somatic cell detection. However, the ionic composition and ambient temperature changes of mastitis cow milk are complex, which seriously interferes with impedance and other data, and easily overwhelms the impedance changes caused by somatic cells.

[0007] To this end, in order to address the problems of weak somatic cell online detection signals, strong interference and difficult quantification, the present invention proposes a sorting device based on a Dean flow microfluidic chip to sort and enrich somatic cells in bovine milk, eliminate the interference of bovine milk ion components on impedance data through control detection of somatic cell-deficient samples, enhance the detection signal through the enrichment of somatic cells, achieve signal sensitization and interference suppression for somatic cell detection, and obtain accurate and effective impedance information. Subsequently, based on the electrical equivalent model of a single cell and using the original impedance data of the milk sample, the number of somatic cells is quantitatively obtained, thereby realizing online quantitative detection of bovine milk somatic cells, which is beneficial to ensuring the quality and safety of dairy products.

[0008] The present invention is achieved through the following technical solutions:

[0009] A Dean flow sorting device for online quantitative detection of bovine milk somatic cells, comprising a real-time bovine milk sample collection unit, a sample inlet throttle valve, a Dean flow microfluidic chip, a somatic cell enriched milk sample outlet throttle valve, a somatic cell depleted milk sample outlet throttle valve, an enriched sample impedance detection unit, a depleted sample impedance detection unit, a data processing unit and an online display unit;

[0010] The real-time milk sample collection unit is connected to the inlet of the Dean flow microfluidic chip through the inlet throttle valve, the Dean flow microfluidic chip has two outlets, namely the somatic cell enriched milk sample outlet and the somatic cell depleted milk sample outlet, the somatic cell enriched milk sample outlet is connected to the enriched sample impedance detection unit through the somatic cell enriched milk sample outlet throttle valve, the somatic cell depleted milk sample outlet is connected to the depleted sample impedance detection unit through the somatic cell depleted milk sample outlet throttle valve, the data processing unit is connected to the enriched sample impedance detection unit and the depleted sample impedance detection unit, and the online display unit is connected to the data processing unit;

[0011] A real-time milk sample collection unit, used to obtain real-time milk samples;

[0012] An inlet throttle valve, used to control the flow rate of the milk sample entering the microfluidic chip;

[0013] Dean flow microfluidic chip for sorting somatic cells in bovine milk;

[0014] A throttle valve at the outlet of the somatic cell enriched milk sample, used to adjust the flow rate of the outlet of the somatic cell enriched milk sample;

[0015] A throttle valve at the outlet of the somatic cell-deficient milk sample, used to control the flow rate of the outlet of the somatic cell-deficient milk sample;

[0016] An enriched sample impedance detection unit, used to detect the impedance value of a somatic cell-enriched milk sample;

[0017] A missing sample impedance detection unit, used to detect the impedance value of a milk sample with somatic cell missing;

[0018] A data processing unit is used to process the signals input from the two impedance detection units, eliminate the interference of ion components on the impedance data, and quantitatively obtain the accurate number of somatic cells using the impedance data according to the electrical equivalent model of the single cell;

[0019] The online display unit is used to display the somatic cell test results of the milk sample in real time.

[0020] Furthermore, the Dean flow microfluidic chip is a flow channel arranged in a spiral shape, and the flow channel is divided into an inlet flow channel and an outlet flow channel with the intersection of the circle center as the dividing point, the inlet flow channel and the outlet flow channel are arranged at intervals from the outside to the inside, and the inlet flow channel and the outlet flow channel are arranged in opposite clockwise directions. Taking the following structure as an example, vice versa, that is, along the fluid flow direction, the inlet flow channel is arranged in a counterclockwise direction from the inlet to the intersection of the circle center, and along the fluid flow direction, the outlet flow channel is arranged in a clockwise direction from the intersection of the circle center to the outlet, and the end of the outlet flow channel is bifurcated into two outlets with unequal cross-sectional areas. The outlet with a larger cross-sectional area on the outer wall is a somatic cell-deficient milk sample outlet, and the outlet with a smaller cross-sectional area on the inner wall is a somatic cell-enriched milk sample outlet.

[0021] Furthermore, the cell sorting principle of the Dean flow microfluidic chip can be briefly described as follows: the fluid flow in the flow channel behaves as a parabolic Poiseuille flow. When the fluid flows in the curved flow channel, the radial pressure and centrifugal force gradient are unbalanced, causing the fluid in the central area of ​​the flow channel to flow counterclockwise and clockwise toward the top and bottom of the flow channel, respectively, to compensate for the low fluid flow near the wall. Therefore, the fluid in the curved flow channel generates two reverse vortices at the bottom and top of the flow channel, namely, the Dean vortex. After the milk sample enters the Dean flow microfluidic sorting chip, the somatic cells and other particles in the curved flow channel are simultaneously subjected to the inertial lift F L and Dean Drag F D Under certain parameter conditions, the particles in the bend can reach F L and F D The equilibrium position of a particle depends on its size.

[0022] Furthermore, taking somatic cells as the sorting objects, in order to achieve the ideal sorting function, reduce the chip flow resistance and improve the detection flux, the cross-sectional height h of the Dean flow microfluidic chip channel is set to 80 μm and the width w is set to 400 μm.

[0023] Furthermore, in order to ensure that the somatic cells with larger sizes at the chip outlet are gathered on the inner wall of the microfluidic channel and realize the effective sorting of the somatic cells, the number of circles is four and the channel spacing is 800 μm.

[0024] Furthermore, the cross-sectional width of the outlet port of the somatic cell-enriched milk sample is 80 μm, and the cross-sectional width of the outlet port of the somatic cell-depleted milk sample is 320 μm.

[0025] Furthermore, the production of Dean flow microfluidic chips is completed by mold injection molding. First, an aluminum main mold is made, and then a laser micromachining process is used to manufacture a microchannel chip mold containing an inlet / outlet. The low spontaneous fluorescence polymer material cycloolefin polymer COP is selected, and the microfluidic chip is processed by injection molding. The chip is aligned, bonded and packaged with high strength by laser thermal welding to ensure the high strength and high consistency of the chip.

[0026] Furthermore, the throughput of the online detection of bovine milk somatic cell count in the present invention can reach 1 mL / min, and the flow rate ratio controlled by the inlet throttle valve, the somatic cell enriched milk sample outlet throttle valve, and the somatic cell-depleted milk sample outlet throttle valve is set to 5:1:4. When the detection flux is 800 μL / min, that is, the flow rate controlled by the inlet throttle valve is 800 μL / min, the flow rates controlled by the somatic cell enriched milk sample outlet throttle valve and the somatic cell-depleted milk sample outlet throttle valve are 160 μL / min and 640 μL / min, respectively.

[0027] A Dean flow sorting method for online quantitative detection of bovine milk somatic cells, the steps are as follows:

[0028] 1. Collect the milk sample being processed or produced through the real-time milk sample collection unit, and control the flow rate of the milk sample through the inlet throttle valve;

[0029] 2. The milk sample enters the Dean flow microfluidic chip, and the somatic cells and other particles are subjected to the inertial lift force F in the curved flow channel. L and Dean Drag F D The double effect of the particles in the curved channel reaches F L and F D The somatic cells are enriched, and other small particles are discharged from the sample outlet of the somatic cell-deficient sample. The flow rates of the two outlets are controlled by the throttle valve of the somatic cell-enriched milk sample outlet and the throttle valve of the somatic cell-deficient milk sample outlet respectively.

[0030] 3. The enriched sample impedance detection unit performs impedance detection on the enriched sample, and the missing sample impedance detection unit performs detection on the sample missing somatic cells;

[0031] 4. The impedance detection data is processed by the data processing unit. The electrical equivalent model of a single cell is used to perform quantitative analysis based on the original impedance data of the milk sample to calculate the number of somatic cells in the milk. The processed somatic cell data information is displayed in real time through the online display unit.

[0032] Beneficial effects:

[0033] 1. Simple operation, no need for complex and time-consuming sample pretreatment, capable of achieving real-time online detection, breaking through the traditional method's reliance on offline laboratory testing, and suitable for industrial continuous detection.

[0034] 2. High detection throughput and fast detection speed. Through the reasonable size parameter setting of the Dean flow microfluidic chip, the system can quickly process milk samples at a detection flux of 1mL / min, greatly improving production efficiency.

[0035] 3. Interference suppression is achieved by using the sorting function of the Dean flow microfluidic chip to separate somatic cells from other components in the milk. By comparing the somatic cell-enriched samples with the somatic cell-deficient samples, the interference of complex conditions such as the ion composition and ambient temperature in the milk on the impedance data is effectively eliminated, ensuring the accuracy of the test results.

[0036] 4. Through the enrichment of somatic cells, the present invention significantly enhances the impedance signal caused by somatic cells, greatly improving the sensitivity of detection. By detecting the enriched samples, clearer signal changes can be obtained than traditional methods, ensuring accurate quantification of somatic cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 : A schematic diagram of an online quantitative detection system for bovine milk somatic cells based on Dean flow sorting technology according to the present invention;

[0038] Figure 2 : A schematic diagram of the sorting principle of the Dean flow microfluidic chip involved in the present invention;

[0039] Figure 3 : Schematic diagram of the size parameters of the Dean flow microfluidic chip involved in the present invention.

[0040] The symbols in the accompanying drawings are:

[0041] 1. Real-time milk sample collection unit;

[0042] 2. Inlet throttle valve;

[0043] 3. Dean flow microfluidic chip;

[0044] 4. Throttle valve for the outlet of somatic cell enriched milk sample;

[0045] 5. Throttle valve for the outlet of somatic cell-deficient milk sample;

[0046] 6. Enriched sample impedance detection unit;

[0047] 7. Missing sample impedance detection unit;

[0048] 8. Data processing unit;

[0049] 9. Online display unit;

[0050] 301, injection port;

[0051] 302, outlet for somatic cell enriched milk sample;

[0052] 303, somatic cell loss milk sample outlet. DETAILED DESCRIPTION

[0053] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. However, the following embodiments are limited to explaining the present invention, and the protection scope of the present invention should include the entire contents of the claims, and through the description of the following embodiments, those skilled in the art can fully implement the entire contents of the claims of the present invention.

[0054] The objective of the present invention is achieved through the following technical solutions:

[0055] Example 1

[0056] like Figure 1 As shown, a Dean flow sorting device for online quantitative detection of bovine milk somatic cells comprises a real-time bovine milk sample collection unit, a sample inlet throttle valve, a Dean flow microfluidic chip, a somatic cell enriched milk sample outlet throttle valve, a somatic cell depleted milk sample outlet throttle valve, an enriched sample impedance detection unit, a depleted sample impedance detection unit, a data processing unit and an online display unit;

[0057] A real-time milk sample collection unit 1 is used to obtain real-time milk samples;

[0058] The injection port throttle valve 2 is used to control the flow rate of the milk sample entering the microfluidic chip to ensure that the sample enters the microfluidic chip at an appropriate speed;

[0059] Dean flow microfluidic chip 3 is the core of the system, responsible for the sorting and enrichment of somatic cells. Through the unique microfluidic structure and Dean flow effect, it can effectively sort somatic cells in milk;

[0060] Throttle valve 4 for the outlet of the somatic cell enriched milk sample, which is used to adjust the flow rate of the outlet of the somatic cell enriched milk sample to ensure sufficient sorting and enrichment;

[0061] A throttle valve 5 at the outlet of the somatic cell-deficient milk sample, which is used to control the flow rate of the outlet of the somatic cell-deficient milk sample to ensure the sorting efficiency;

[0062] An enriched sample impedance detection unit 6, used to detect the impedance value of the somatic cell-enriched milk sample;

[0063] A missing sample impedance detection unit 7, used to detect the impedance value of a somatic cell-deficient milk sample;

[0064] The data processing unit 8 is used to process the signals inputted from the two impedance detection units, eliminate the interference of ion components on the impedance data, and quantitatively obtain the accurate number of somatic cells using the impedance data according to the electrical equivalent model of the single cell;

[0065] The online display unit 9 is used to display the somatic cell detection result of the milk sample in real time.

[0066] Furthermore, the Dean flow microfluidic chip, as the core of the present invention, is a double-helix rectangular cross-section flow channel, including an inlet 301, a somatic cell enriched milk sample outlet 302, and a somatic cell depleted milk sample outlet 303.

[0067] Furthermore, if Figure 2 As shown in the figure, the cell sorting principle of the Dean flow microfluidic chip can be briefly described as follows: the fluid flow in the flow channel is a parabolic Poiseuille flow. When the fluid flows in the curved channel, the radial pressure and centrifugal force gradient are unbalanced, causing the fluid in the center area of ​​the flow channel to flow counterclockwise and clockwise toward the top and bottom of the flow channel, respectively, to compensate for the low fluid flow near the wall. Therefore, the fluid in the curved channel generates two reverse vortices at the bottom and top of the channel, namely, the Dean vortex. After the milk sample enters the Dean flow microfluidic sorting chip, the somatic cells and other particles in the curved channel are simultaneously subjected to the inertial lift F L and Dean Drag F D Under certain parameter conditions, the particles in the bend can reach F L and F D The equilibrium position of a particle depends on its size.

[0068] Furthermore, if Figure 3 As shown, taking somatic cells as the sorting objects, in order to achieve the ideal sorting function, reduce the chip flow resistance and improve the detection throughput, the cross-sectional height h of the Dean flow microfluidic chip flow channel is set to 80 μm and the width w is set to 400 μm.

[0069] Furthermore, if Figure 3 As shown, in order to ensure that the larger somatic cells at the chip outlet are gathered on the inner wall of the microchannel and realize the effective sorting of somatic cells, the structure of the Dean flow microfluidic chip is a double helix with four turns and a channel spacing of 800μm.

[0070] Furthermore, if Figure 3 As shown, the inner wall outlet of the Dean flow microfluidic chip is a somatic cell-enriched milk sample outlet, whose cross-sectional width is 80 μm, and the outer wall outlet is a somatic cell-deficient milk sample outlet, whose cross-sectional width is 320 μm.

[0071] Furthermore, the production of Dean flow microfluidic chips is completed by mold injection molding. First, an aluminum main mold is made, and then a laser micromachining process is used to manufacture a microchannel chip mold containing an inlet / outlet. The low spontaneous fluorescence polymer material cycloolefin polymer COP is selected, and the microfluidic chip is processed by injection molding. The chip is aligned, bonded and packaged with high strength by laser thermal welding to ensure the high strength and high consistency of the chip.

[0072] Furthermore, the throughput of the online detection of bovine milk somatic cell count in the present invention can reach 1 mL / min, and the flow rate ratio controlled by the inlet throttle valve, the somatic cell enriched milk sample outlet throttle valve, and the somatic cell-depleted milk sample outlet throttle valve is set to 5:1:4. When the detection flux is 800 μL / min, that is, the flow rate controlled by the inlet throttle valve is 800 μL / min, the flow rates controlled by the somatic cell enriched milk sample outlet throttle valve and the somatic cell-depleted milk sample outlet throttle valve are 160 μL / min and 640 μL / min, respectively.

[0073] Example 2

[0074] A Dean flow sorting method for online quantitative detection of bovine milk somatic cells, the steps are as follows:

[0075] 1. Collect milk samples being processed or produced through the real-time milk sample collection unit to ensure that the milk samples obtained truly reflect the current somatic cell level of the dairy cow. Control the flow rate of the milk sample through the inlet throttle valve to ensure that the milk enters the Dean flow microfluidic chip at an appropriate speed. Too fast sample flow rate will affect the sorting efficiency of somatic cells, while too slow will prolong the detection time and reduce the detection throughput.

[0076] 2. The milk sample enters the Dean flow microfluidic chip. The double helix structure of the chip and the shape and size of the microchannel determine the sorting effect. The specific principle is: somatic cells and other particles are affected by the inertial lift F in the curved channel. L and Dean Drag F D Under certain parameter conditions, the particles in the bend can reach F L and F D The equilibrium position of the particles depends on their size. By setting the reasonable related parameters mentioned above, the diversion of somatic cell enriched and depleted samples is achieved. At the outlet of the somatic cell enriched sample, somatic cells are effectively enriched, and the outlet of the somatic cell depleted sample mainly discharges other small particles. The flow rates of the two outlets are controlled by the throttle valve of the somatic cell enriched milk sample outlet and the throttle valve of the somatic cell depleted milk sample outlet to ensure the best sorting effect.

[0077] 3. The somatic cell enriched and depleted samples flow into the corresponding impedance detection units respectively. The impedance value of the somatic cell enriched milk sample measured by the enriched sample impedance detection unit is The impedance value of the milk sample with somatic cell deficiency measured by the impedance detection unit is By comparing the differences between the two, the interference of factors such as milk ion composition and ambient temperature on the impedance data is eliminated, making the impedance changes caused by somatic cells more significant.

[0078] 4. The impedance detection data is processed by the data processing unit. First, the interference of the impedance signal caused by the complex ion composition in the milk and the change of ambient temperature is eliminated. Then, the electrical equivalent model of a single cell is used to perform quantitative analysis based on the original impedance data of the milk sample to calculate the number of somatic cells in the milk. The complex dielectric constant of the milk sample can be obtained from the impedance data. , the complex dielectric constants corresponding to the somatic cell enriched and depleted samples can be expressed as and According to the cell polarization model in continuous media, ,in, is the equivalent complex dielectric constant of somatic cells, which can be obtained experimentally, and p is the volume fraction of somatic cells in the somatic cell-enriched sample, which is directly related to the number of somatic cells N. ,in is the volume of the somatic cell, It is the volume of the detection pool. Combined with the known or measurable data such as the characteristic size parameters and electrical parameters of somatic cells and the size of the detection pool, the quantitative somatic cell count can be obtained. The processed somatic cell data information is displayed in real time through the online display unit, which is convenient for dairy producers or testers to grasp the somatic cell concentration of milk in a timely manner, effectively helping users make timely decisions and ensure the safety of dairy product quality.

[0079] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A Dean flow sorting device for online quantitative detection of bovine milk somatic cells, characterized in that: It includes a real-time milk sample collection unit, a sample inlet throttle valve, a Dean flow microfluidic chip, a somatic cell enriched milk sample outlet throttle valve, a somatic cell depleted milk sample outlet throttle valve, an enriched sample impedance detection unit, a depleted sample impedance detection unit, a data processing unit and an online display unit; The real-time milk sample collection unit is connected to the inlet of the Dean flow microfluidic chip through the inlet throttle valve, the Dean flow microfluidic chip has two outlets, namely the somatic cell enriched milk sample outlet and the somatic cell depleted milk sample outlet, the somatic cell enriched milk sample outlet is connected to the enriched sample impedance detection unit through the somatic cell enriched milk sample outlet throttle valve, the somatic cell depleted milk sample outlet is connected to the depleted sample impedance detection unit through the somatic cell depleted milk sample outlet throttle valve, the data processing unit is connected to the enriched sample impedance detection unit and the depleted sample impedance detection unit, and the online display unit is connected to the data processing unit; The Dean flow microfluidic chip is a flow channel arranged in a spiral shape, and the flow channel is divided into an inlet flow channel and an outlet flow channel with the intersection of the center of the circle as the dividing point. The inlet flow channel and the outlet flow channel are arranged at intervals from the outside to the inside, and the inlet flow channel and the outlet flow channel are arranged in a counterclockwise direction. The end of the outlet flow channel is bifurcated into two outlets with different cross-sectional areas. The outlet with a larger cross-sectional area on the outer wall is a somatic cell-deficient milk sample outlet, and the outlet with a smaller cross-sectional area on the inner wall is a somatic cell-enriched milk sample outlet.

2. A Dean flow sorting device for online quantitative detection of bovine milk somatic cells according to claim 1, characterized in that: The cross-sectional height h of the flow channel of the Dean flow microfluidic chip is set to 80 μm, and the width w is set to 400 μm.

3. The Dean flow sorting device for online quantitative detection of bovine milk somatic cells according to claim 1, characterized in that: The Dean flow microfluidic chip has four circles around it, and the flow channel spacing is 800 μm.

4. The Dean flow sorting device for online quantitative detection of bovine milk somatic cells according to claim 1, characterized in that: The cross-sectional width of the outlet of the somatic cell-enriched milk sample is 80 μm, and the cross-sectional width of the outlet of the somatic cell-depleted milk sample is 320 μm.

5. The Dean flow sorting device for online quantitative detection of bovine milk somatic cells according to claim 1, characterized in that: The flow rate ratio controlled by the inlet throttle valve, the somatic cell-enriched milk sample outlet throttle valve, and the somatic cell-depleted milk sample outlet throttle valve is set to 5:1:

4.

6. A Dean flow sorting method for online quantitative detection of bovine milk somatic cells, characterized in that: Here are the steps: Step 1, collecting the milk sample being processed or produced by the real-time milk sample collection unit, and controlling the flow rate of the milk sample by the inlet throttle valve; Step 2: The milk sample enters the Dean flow microfluidic chip, and the somatic cells and other particles are subjected to the inertial lift force F in the curved flow channel. L and Dean Drag F D The double effect of the particles in the curved channel reaches F L and F D The somatic cells are enriched, and other small particles are discharged from the sample outlet of the somatic cell-deficient sample. The flow rates of the two outlets are controlled by the throttle valve of the somatic cell-enriched milk sample outlet and the throttle valve of the somatic cell-deficient milk sample outlet respectively. Step 3: The enriched sample impedance detection unit performs impedance detection on the enriched sample, and the missing sample impedance detection unit performs detection on the sample missing somatic cells; Step 4: The impedance detection data is processed by a data processing unit. A single-cell electrical equivalent model is used to perform quantitative analysis based on the original impedance data of the milk sample to calculate the number of somatic cells in the milk. The processed somatic cell data information is displayed in real time through an online display unit.

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