Method for monitoring and cleaning blockage of nozzle of flow cytometer

Abstract

The invention discloses a flow cytometer nozzle blockage monitoring and cleaning method, which belongs to the field of cell sorting, and is characterized in that a flow resistance element is connected in a sheath fluid output pipeline to increase the flow resistance of the whole flow path; the blockage state of the nozzle is analyzed through pressure detection of a flow cavity, a flowmeter is connected between a sheath liquid flow path and a liquid drop generator flow path to facilitate evaluation of flow resistance of all parts in the liquid path, and circuit equivalence is performed on the flow path from an inlet of a sheath liquid tube to an outlet of the nozzle according to the flow path-circuit equivalence principle. And calculating the flow resistance of each component in the liquid path, calculating the increasing multiplying power of the nozzle flow resistance at the t-th moment, and judging the blockage condition of the nozzle and whether the nozzle can be automatically cleaned according to the error limit and the increasing multiplying power of the nozzle flow resistance.

Description

Technical Field

[0001] The invention relates to the field of cell sorting, and in particular to a method for monitoring and cleaning the nozzle blockage of a flow cell sorter. Background Art

[0002] A flow cytometer is a device for high-throughput analysis and sorting and enrichment of cells. It performs optical detection based on the physical, chemical, immune and other characteristic parameter information of cells, and sorts and enriches specific cell subpopulations through a preselected parameter range. Compared with a flow cytometer, the sorter also contains two important unique devices in hardware: a droplet generator and a nozzle. Among them, the droplet generator is installed at the front end of the flow chamber, and the piezoelectric transducer acts on the sheath liquid and sample flow at ultra-high frequency to generate droplets of uniform size and equal intervals; the nozzle is installed at the outlet of the flow chamber, and the tiny throttle holes on it limit the size of the generated droplets, usually with an aperture of 70 to 130 μm. Due to the large flow resistance of the tiny throttle holes of the nozzle, the liquid flow system of the sorter is very different from that of the analyzer, especially the sheath liquid pressure used to achieve three-dimensional fluid dynamic focusing will be increased by ten times or even dozens of times. Fluid pumps commonly used in flow cytometers to drive sheath fluids at constant pressure or constant current, such as diaphragm pumps, peristaltic pumps, and syringe pumps, are generally difficult to use in sorters. Therefore, flow cytometers usually use pneumatic control systems to drive sheath fluids and sample flows at constant pressure or constant current.

[0003] In flow cytometers, the tiny aperture of the nozzle usually poses a risk of clogging. When the nozzle is partially clogged, it will affect the normal generation of droplets; it will also change the sheath fluid pressure in the droplet generator, thereby affecting the delay parameters of the sorting droplets. At present, the user often observes the final state of droplet generation to determine whether the nozzle has a clogging problem. This method usually has a certain degree of subjectivity, places higher requirements on the user's instrument usage experience, and cannot determine the degree of nozzle clogging in real time. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, one of the objectives of the present invention is to provide a flow cell sorter nozzle clogging monitoring method that can automatically determine the clogging degree of the nozzle.

[0005] One of the purposes of the present invention is achieved by the following technical solution:

[0006] A flow cell sorter nozzle blockage monitoring and cleaning method comprises the following steps:

[0007] Build a flow cell sorter, connect the gas supply path with the sample path and the sheath liquid path, the sample path and the sheath liquid path are connected with the droplet generation path, the sheath liquid path is provided with a control valve and a flow resistance element, and the droplet generation path includes a nozzle;

[0008] Get the upper limit of the nozzle flow resistance increase factor and the limiting rate of change of pressure in the flow chamber of the flow cell sorter

[0009] The nozzle is installed into the flow cell sorter, and the pressure in the flow cell chamber is recorded when the nozzle is completely unblocked in the analysis or sorting state of the flow cell sorter.

[0010] In the analysis or sorting state of the flow cell sorter, the real-time pressure in the flow cell chamber is collected.

[0011] According to the formula Calculation error limit

[0012] A flow meter is connected between the sheath liquid flow path and the droplet generation flow path, the nozzle is installed in the flow cell sorter, the flow resistance element is not operated through the control valve, and the sheath liquid flow rate Q1 of the flow meter is collected; the nozzle is removed from the flow cell sorter, the flow resistance element is operated through the control valve, and the sheath liquid flow rate Q2 of the flow meter is collected; the nozzle is installed in the flow cell sorter, the flow resistance element is operated through the control valve, and the sheath liquid flow rate Q3 of the flow meter is collected;

[0013] According to the flow path-circuit equivalence principle, the flow path from the sheath liquid tube inlet to the nozzle outlet is equivalent to the circuit, and the following is obtained:

[0014]

[0015] Wherein, LR1 is the flow resistance of the nozzle; LR2 is the flow resistance of the flow chamber and the flow cavity; LR3 is the flow resistance of the flow resistance element; P2 is the driving gas pressure in the sheath liquid barrel;

[0016] Calculate LR1, LR2 and LR3 according to formulas (1)-(3), let is the flow resistance of the nozzle in the unblocked state, then the increase factor of the nozzle flow resistance at time t is

[0017] when When the nozzle is blocked and cannot be automatically cleaned; and When the nozzle is blocked, it is judged that the nozzle is blocked and can be automatically cleaned; when When the nozzle is judged to be not blocked or partially blocked but no automatic cleaning is required.

[0018] Furthermore, when and The automatic cleaning steps are as follows:

[0019] S1: Obtain the lower limit value of the flow resistance increase ratio of the nozzle

[0020] S2: maintaining or increasing the pressure of the sheath fluid flow path, disabling the flow resistance element through the control valve, and running the flow cytometer for a preset time;

[0021] S3: Make the flow resistance element work through the control valve, and calculate the and η(t);

[0022] S4: When When the automatic cleaning is finished; when When , return to step S2 until

[0023] Furthermore, when the flow resistance element is working, the flow cell sorter is in an analysis or sorting state; when the flow resistance element is not working, the flow cell sorter is in a cleaning state.

[0024] Furthermore, the control valve is a three-way two-position valve. When position A is connected to position B, the flow resistance element does not work, and when position A is connected to position C, the flow resistance element works.

[0025] Furthermore, according to the equivalent circuit diagram of the nozzle being installed in the flow cell sorter and the flow resistance element being operated by the control valve, the following is obtained: 100%, thus

[0026] Furthermore, the flow resistance element is a throttle valve or a slender tube.

[0027] Furthermore, when When the nozzle cannot be automatically cleaned, the nozzle is removed from the flow cell sorter for ultrasonic cleaning.

[0028] Furthermore, the flow resistance of the nozzle in the unblocked state is This is the state of a brand new nozzle when it is used for the first time or after the nozzle has just been ultrasonically cleaned.

[0029] Furthermore, the upper limit of the nozzle flow resistance increase ratio is and the limiting rate of change of pressure in the flow chamber of the flow cell sorter is the system parameter.

[0030] Furthermore, the nozzle aperture is 70-130 μm.

[0031] Compared with the prior art, the flow cell sorter nozzle blockage monitoring and cleaning method of the present invention increases the flow resistance of the entire flow path by connecting a flow resistance element in the sheath liquid output pipeline, and analyzes the blockage state of the nozzle by pressure detection of the flow chamber. In order to facilitate the evaluation of the flow resistance of each component in the liquid path, a flow meter is connected between the sheath liquid flow path and the droplet generator flow path. According to the flow path-circuit equivalence principle, the flow path from the sheath liquid tube inlet to the nozzle outlet is circuit equivalent, the flow resistance of each component in the liquid path is calculated, and the increase ratio of the nozzle flow resistance at the tth moment is calculated. The nozzle blockage condition and whether it can be automatically cleaned are judged according to the error limit and the increase ratio of the nozzle flow resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flow chart of the flow cell sorter nozzle blockage monitoring and cleaning method of the present invention;

[0033] Figure 2 It is a schematic diagram of the structure of the flow cell sorter nozzle blockage monitoring and cleaning method of the present invention;

[0034] Figure 3 It is a schematic diagram of connecting a flow meter between the sheath liquid flow path and the droplet generation flow path of the present invention;

[0035] Figure 4 It is an equivalent circuit diagram when the nozzle is inserted and the A position and the B position of the three-way two-position valve are connected;

[0036] Figure 5 It is an equivalent circuit diagram when the nozzle is pulled out and the A position and C position of the three-way two-position valve are connected;

[0037] Figure 6 This is the equivalent circuit diagram when the nozzle is inserted and the A position and C position of the three-way two-position valve are connected.

[0038] In the figure: 10, air supply circuit; 11, compressor; 12, filter; 13, water mist separator; 14, pressure reducing valve; 15, gas storage tank; 16, safety valve; 20, sample flow path; 21, first electrical proportional valve; 22, first pressure gauge; 23, sample tank; 24, sample tube; 25, sampling needle; 26, first liquid level gauge; 30, sheath liquid flow path; 31, second electrical proportional valve; 32, second pressure gauge; 33, sheath liquid barrel; 34, second liquid level gauge; 35, flow resistance element; 36, control valve; 40, droplet generation flow path; 41, third pressure gauge; 42, flow cavity; 43, flow chamber; 44, nozzle; 50, flow meter. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0041] See also Figure 1 The present invention provides a flow cell sorter nozzle blockage monitoring and cleaning method, comprising the following steps:

[0042] A flow cell sorter is constructed, an air supply path is connected to a sample path and a sheath liquid path, the sample path and the sheath liquid path are connected to a droplet generation path, the sheath liquid path is provided with a control valve and a flow resistance element, and the droplet generation path includes a nozzle;

[0043] Get the upper limit of the nozzle flow resistance increase factor and the limiting rate of change of pressure in the flow chamber of the flow cell sorter

[0044] Install the nozzle into the flow cell sorter. When the flow cell sorter is in the analysis or sorting state, record the pressure in the flow chamber when the nozzle is completely unblocked.

[0045] During the analysis or sorting of the flow cell sorter, the real-time pressure in the flow chamber is collected.

[0046] According to the formula Calculation error limit

[0047] A flow meter is connected between the sheath liquid flow path and the droplet generation flow path, the nozzle is installed in the flow cell sorter, the flow resistance element is disabled by the control valve, and the sheath liquid flow Q1 of the flow meter is collected; the nozzle is removed from the flow cell sorter, the flow resistance element is enabled by the control valve, and the sheath liquid flow Q2 of the flow meter is collected; the nozzle is installed in the flow cell sorter, the flow resistance element is enabled by the control valve, and the sheath liquid flow Q3 of the flow meter is collected;

[0048] According to the flow path-circuit equivalence principle, the flow path from the sheath liquid tube inlet to the nozzle outlet is equivalent to the circuit, and the following is obtained:

[0049]

[0050] Among them, LR1 is the flow resistance of the nozzle; LR2 is the flow resistance of the flow chamber and the flow cavity; LR3 is the flow resistance of the flow resistance element; P2 is the driving gas pressure in the sheath liquid barrel;

[0051] Calculate LR1, LR2 and LR3 according to formulas (1)-(3), let is the flow resistance of the nozzle in the unblocked state, then the increase rate of the nozzle flow resistance at time t is

[0052] when When the nozzle is blocked, it is judged that it cannot be cleaned automatically; when and When the nozzle is blocked, it can automatically clean it; when When the nozzle is judged to be not blocked or partially blocked but no automatic cleaning is required.

[0053] Please continue reading Figure 2 , the flow cytometer is specifically constructed as follows: the flow cytometer includes an air supply path 10, a sample path 20, a sheath liquid path 30, and a droplet generation path 40. The sample path 20 and the sheath liquid path 30 are respectively connected to the air supply path 10, the air supply path 10 drives the sample in the sample path 20 and the sheath liquid in the sheath liquid path 30, the sample path 20 and the sheath liquid path 30 are connected to the droplet generation path 40, and the sample in the sample path 20 and the sheath liquid in the sheath liquid path 30 enter the droplet generation path 40 to generate droplets.

[0054] The gas supply circuit 10 includes a compressor 11, a filter 12, a water mist separator 13, a pressure reducing valve 14 and a gas storage tank 15 connected in sequence, and a safety valve 16 is installed on the gas storage tank 15. The pressure reducing valve 14 is used to preliminarily adjust the output air pressure of the compressor 11, which can be adjusted manually or electrically. The output air pressure is generally set to 1.2 to 2 times the maximum air supply pressure in the sheath liquid flow path 30, but does not exceed the maximum allowable input air pressure value of the first electrical proportional valve 21 and the second electrical proportional valve 31. The gas storage tank 15 is used to store the compressed gas after the pressure reduction of the pressure reducing valve 14, and the safety valve 16 is used to ensure the safety of the air supply pressure at its rear end. The safety valve 16 can use a pressure switch with a contact tongue spring, that is, when the air pressure in the gas storage tank 15 is higher than 80% to 100% of the maximum allowable input air pressure value of the first electrical proportional valve 21 or the second electrical proportional valve 31, the safety valve 16 automatically opens and releases air to reduce the pressure of the gas storage tank 15 to the set pressure value; otherwise, the safety valve 16 is always in a closed state.

[0055] The sample flow path 20 includes a first electrical proportional valve 21, a first pressure gauge 22, a sample tank 23, a sample tube 24 and a sampling needle 25 which are connected in sequence, and a first liquid level gauge 26 is installed on the sample tube 24. The first electrical proportional valve 21 is used to adjust the air pressure in the sample tube 24; the first pressure gauge 22 is used to monitor the output air pressure of the first electrical proportional valve 21 in real time; the compressed gas output by the first electrical proportional valve 21 is input into the sample tank 23 to drive the sample under positive pressure; the sample tube 24 is fixed in the sample tank 23, and the sample in the sample tube 24 flows out through the sampling needle 25 under air pressure; the sampling needle 25 is matched with a first liquid level gauge 26, which is a capacitive liquid level gauge, used for sample transmission and monitoring the liquid level height of the sample in the sample tube 24.

[0056] The sheath liquid flow path 30 includes a second electrical proportional valve 31, a second pressure gauge 32, a sheath liquid barrel 33 control valve 36 and a flow resistance element 35 which are connected in sequence, and a second liquid level gauge 34 is installed in the sheath liquid barrel 33. The second electrical proportional valve 31 is used to adjust the air pressure in the sheath liquid barrel 33; the second pressure gauge 32 is used to monitor the output air pressure of the second electrical proportional valve 31 in real time; the compressed gas output by the second electrical proportional valve 31 is input into the sheath liquid barrel 33 to drive the sheath liquid with positive pressure; the second liquid level gauge 34 is installed in the sheath liquid barrel 33 to monitor the liquid level of the sheath liquid; the control valve 36 is a three-way two-position valve. When the A position is connected to the B position, the flow resistance element 35 does not work, and the flow cell sorter is in a cleaning state; when the A position is connected to the C position, the flow resistance element 35 works, and the flow cell sorter is in an analysis or sorting state. The flow resistance element 35 is a throttle valve or a slender tube. In this embodiment, the flow resistance element 35 adopts a microporous throttle valve. The flow resistance element 35 is installed in the sheath liquid output pipeline to increase the flow resistance of the entire flow path, and the third pressure gauge 41 detects the pressure of the convection cavity 42 to analyze the blockage state of the nozzle 44. The second liquid level meter 34 is preferably a continuous liquid level sensor of float type or ultrasonic principle.

[0057] The droplet generation flow path 40 includes a flow chamber 42, a flow chamber 43 and a nozzle 44 connected in sequence, and a third pressure gauge 41 is installed in the flow chamber 42. The flow chamber 42 in the droplet generation flow path 40 is used for three-dimensional fluid dynamic focusing of the sample. After the sheath liquid and the sample flow into the flow chamber 42, the sheath liquid wraps the sample to achieve single-cell arrangement of cells in the sample; the third pressure gauge 41 is connected to the pipeline in the flow chamber 42 to monitor the hydraulic pressure of the fluid in the flow chamber 42; the inlet of the flow chamber 43 is connected to the outlet of the flow chamber 42 for flow detection and analysis of cells; the inlet of the nozzle 44 is connected to the outlet of the flow chamber 43; the inner diameter of the nozzle 44 is 70 to 130 μm, and is used to generate droplets of stable size.

[0058] The upper limit of the nozzle flow resistance increase factor and the limiting rate of change of pressure in the flow chamber of the flow cell sorter is the system parameter.

[0059] Please continue reading Figure 3 When the sheath liquid flow path 30 and the droplet generation flow path 40 are connected to the flow meter 50, the flow path from the sheath liquid tube inlet to the nozzle 44 outlet is circuit equivalent according to the flow path-circuit equivalent principle. Among them, (1) the nozzle 44 is plugged in, and the A position and the B position of the three-way two-position valve are connected. The equivalent circuit is as follows Figure 4 (2) When the nozzle 44 is pulled out and the A position and the C position of the three-way two-position valve are connected, the equivalent circuit is as follows: Figure 5 (3) When the nozzle 44 is inserted and the A position and C position of the three-way two-position valve are connected, the equivalent circuit is as follows: Figure 6 The equivalent relationship between the circuit and the parameters in the flow path is shown in Table 1:

[0060] Table 1 Equivalent relationship between various parameters in circuit and flow path

[0061]

[0062] According to Figures (4) to (6) and the equivalent method of each parameter in Table 1, the flow resistances LR1, LR2 and LR3 of each part are:

[0063]

[0064] When the i-th nozzle model is installed, the pressure in the flow chamber 42 detected by the third pressure gauge 41 is collected at equal time intervals. According to formula (2), the pressure in the flow chamber at time t is calculated relative to the pressure when there is no blockage. The error limit

[0065]

[0066] When the error limit The pressure in the flow chamber 42 exceeds the limit change rate allowed for normal operation of the instrument. When the upper computer software prompts that the instrument needs to be stopped and the nozzle 44 needs to be removed for ultrasonic cleaning; otherwise, it is considered that the nozzle 44 is not blocked or the blockage state is not enough to affect the normal operation of the instrument. is the default setting of the instrument and can be confirmed according to the actual operation of the instrument. The completely unblocked state is generally the default state of a brand new nozzle when it is used for the first time or the nozzle has just completed ultrasonic cleaning. The flow resistance of the nozzle 44 of the i-th model in the unblocked state can be determined by formula (1):

[0067] According to the equivalent circuit Figure 6 , then the error limit of the pressure in the flow chamber is Can be transformed into:

[0068]

[0069] According to formula (5), the increase ratio η(t) of the flow resistance of the nozzle 44 at the tth moment is derived:

[0070]

[0071] When using the i-th type of nozzle 44, the instrument will set two parameters by default: and They respectively represent the upper limit and lower limit of the flow resistance increase factor of the i-th type nozzle 44.

[0072] when and The automatic cleaning steps are as follows:

[0073] S1: Get the lower limit of the nozzle flow resistance increase ratio

[0074] S2: Maintain or increase the pressure of the sheath fluid flow path, disable the flow resistance element by controlling the valve, and run the flow cell sorter for a preset time;

[0075] S3: Make the flow resistance element work by controlling the valve, and calculate the and η(t);

[0076] S4: When When the automatic cleaning is finished; when When , return to step S2 until

[0077] when When the nozzle 44 cannot be automatically cleaned, the nozzle 44 is removed from the flow cell sorter for ultrasonic cleaning.

[0078] Compared with the prior art, the flow cell sorter nozzle blockage monitoring and cleaning method of the present invention increases the flow resistance of the entire flow path by connecting a flow resistance element 35 in the sheath liquid output pipeline, and analyzes the blockage state of the nozzle by detecting the pressure of the flow chamber 42. In order to facilitate the evaluation of the flow resistance of each component in the liquid path, a flow meter 50 is connected between the sheath liquid flow path and the droplet generator flow path. According to the flow path-circuit equivalence principle, the flow path from the sheath liquid tube inlet to the nozzle 44 outlet is circuit equivalent, the flow resistance of each component in the liquid path is calculated, and the increase ratio of the flow resistance of the nozzle 44 at the tth moment is calculated. According to the error limit and the increase ratio of the nozzle flow resistance, the blockage state of the nozzle 44 and whether it can be automatically cleaned are judged.

[0079] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which are equivalent modifications and improvements made to the above embodiments based on the essential technology of the present invention, and all of them belong to the protection scope of the present invention.

Claims

1. A flow cell sorter nozzle blockage monitoring and cleaning method, characterized in that: The following steps are involved: Build a flow cell sorter, connect the gas supply path with the sample path and the sheath liquid path, the sample path and the sheath liquid path are connected with the droplet generation path, the sheath liquid path is provided with a control valve and a flow resistance element, and the droplet generation path includes a nozzle; Get the upper limit of the nozzle flow resistance increase factor and the limiting rate of change of pressure in the flow chamber of the flow cell sorter The nozzle is installed into the flow cell sorter, and the pressure in the flow cell chamber is recorded when the nozzle is completely unblocked in the analysis or sorting state of the flow cell sorter. In the analysis or sorting state of the flow cell sorter, the real-time pressure in the flow cell chamber is collected. According to the formula Calculation error limit A flow meter is connected between the sheath liquid flow path and the droplet generation flow path, the nozzle is installed in the flow cell sorter, the flow resistance element is not operated through the control valve, and the sheath liquid flow rate Q1 of the flow meter is collected; the nozzle is removed from the flow cell sorter, the flow resistance element is operated through the control valve, and the sheath liquid flow rate Q2 of the flow meter is collected; the nozzle is installed in the flow cell sorter, the flow resistance element is operated through the control valve, and the sheath liquid flow rate Q3 of the flow meter is collected; According to the flow path-circuit equivalence principle, the flow path from the sheath liquid tube inlet to the nozzle outlet is equivalent to the circuit, and the following is obtained: Wherein, LR1 is the flow resistance of the nozzle; LR2 is the flow resistance of the flow chamber and the flow cavity; LR3 is the flow resistance of the flow resistance element; P2 is the driving gas pressure in the sheath liquid barrel; Calculate LR1, LR2 and LR3 according to formulas (1)-(3), let is the flow resistance of the nozzle in the unblocked state, then the increase factor of the nozzle flow resistance at time t is when When the nozzle is blocked and cannot be automatically cleaned; and When the nozzle is blocked, it is judged that the nozzle is blocked and can be automatically cleaned; when When the nozzle is judged to be not blocked or partially blocked but no automatic cleaning is required.

2. The method for monitoring nozzle blockage of a flow cell sorter according to claim 1, characterized in that: when and The automatic cleaning steps are as follows: S1: Obtain the lower limit value of the flow resistance increase ratio of the nozzle S2: maintaining or increasing the pressure of the sheath fluid flow path, disabling the flow resistance element through the control valve, and running the flow cytometer for a preset time; S3: Make the flow resistance element work through the control valve, and calculate the and η(t); S4: When When the automatic cleaning is finished; when When , return to step S2 until 3. The flow cell sorter nozzle clogging monitoring method according to claim 1, characterized in that: When the flow resistance element is working, the flow cell sorter is in an analysis or sorting state; when the flow resistance element is not working, the flow cell sorter is in a cleaning state.

4. The method for monitoring nozzle blockage of a flow cell sorter according to claim 3, characterized in that: The control valve is a three-way two-position valve. When the A position is connected to the B position, the flow resistance element does not work, and when the A position is connected to the C position, the flow resistance element works.

5. The method for monitoring nozzle blockage of a flow cell sorter according to claim 1, characterized in that: According to the equivalent circuit diagram of the nozzle being installed in the flow cell sorter and the flow resistance element being operated by the control valve, the following is obtained: Thus, it is concluded 6. The method for monitoring nozzle blockage of a flow cell sorter according to claim 1, characterized in that: The flow resistance element is a throttle valve or a slender tube.

7. The method for monitoring nozzle blockage of a flow cell sorter according to claim 1, characterized in that: when When the nozzle is clogged and cannot be automatically cleaned, the nozzle is removed from the flow cell sorter for ultrasonic cleaning.

8. The method for monitoring nozzle blockage of a flow cell sorter according to claim 1, characterized in that: The flow resistance of the nozzle in the non-blocked state This is the state of a brand new nozzle when it is used for the first time or after the nozzle has just been ultrasonically cleaned.

9. The method for monitoring nozzle blockage of a flow cell sorter according to claim 1, characterized in that: The upper limit of the nozzle flow resistance increase ratio is and the limiting rate of change of pressure in the flow chamber of the flow cell sorter is the system parameter.

10. The method for monitoring nozzle blockage of a flow cell sorter according to claim 1, characterized in that: The nozzle aperture is 70-130 μm.

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