A flow cell sorter nozzle blockage monitoring and cleaning method

Abstract

The present invention discloses a flow cell sorter nozzle clogging monitoring and cleaning method, belonging to the field of cell sorting. The flow cell sorter nozzle clogging monitoring and cleaning method of the present invention connects a flow resistance element to a sheath liquid output pipeline to increase the flow resistance of the entire flow path, and analyzes the nozzle clogging state by pressure detection of a flow chamber. 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. The flow path between the sheath liquid tube inlet and the nozzle outlet is subjected to circuit equivalence according to the flow path-circuit equivalence principle, and the flow resistance of each component in the liquid path is calculated. The increase ratio of the nozzle flow resistance at time t is calculated, and the nozzle clogging state and whether automatic cleaning is possible are determined based on the error limit and the increase ratio of the nozzle flow resistance.

Description

Technical Field

[0001] The present invention relates to the field of cell sorting, and in particular to a method for monitoring and cleaning the blockage of a nozzle 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 physical, chemical, and immunological characteristics of cells, and then sorts and enriches specific cell subpopulations within a preselected parameter range. Compared to flow cytometers, flow cytometers also incorporate two key hardware components: a droplet generator and a nozzle. The droplet generator is mounted at the front end of the flow chamber, where a piezoelectric transducer applies ultrahigh frequency energy to the sheath fluid and sample streams to generate uniformly sized, evenly spaced droplets. The nozzle, mounted at the flow chamber outlet, features a tiny orifice that limits the size of the generated droplets, typically with an aperture of 70 to 130 μm. Due to the significant flow resistance of the nozzle's tiny orifice, the fluidics system of a flow cytometer differs significantly from that of an analyzer. In particular, the sheath fluid pressure required to achieve three-dimensional hydrodynamic focusing can be increased tenfold or even dozens of times. Fluid pumps commonly used in flow cytometers to drive sheath fluid at constant pressure or constant flow, such as diaphragm pumps, peristaltic pumps, and syringe pumps, are generally difficult to use in sorters. Therefore, flow cytometers typically use pneumatic control systems to drive the sheath fluid and sample flow at constant pressure or constant flow.

[0003] In flow cytometry sorters, the tiny nozzle aperture often presents a risk of clogging. Partial nozzle blockage can affect droplet formation and alter the sheath fluid pressure in the droplet generator, affecting the droplet sorting delay parameters. Currently, nozzle clogging is often determined by the user observing the final droplet formation state. This method is often subjective, requires a high level of user experience with the instrument, and cannot determine the degree of nozzle blockage in real time. Summary of the Invention

[0004] In order to overcome the deficiencies 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 degree of nozzle clogging.

[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 cytometer, connect the air supply path to the sample path and the sheath fluid path, the sample path and the sheath fluid path are connected to a droplet generation path, the sheath fluid 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 a flow cytometer

[0009] The nozzle is installed in the flow cell sorter, and the pressure in the flow 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, real-time pressure in the flow 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 cytometer, the flow resistance element is disabled by the control valve, and the sheath liquid flow rate Q1 of the flow meter is collected; the nozzle is removed from the flow cytometer, the flow resistance element is activated by the control valve, and the sheath liquid flow rate Q2 of the flow meter is collected; the nozzle is installed in the flow cytometer, the flow resistance element is activated by 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 fluid tube inlet to the nozzle outlet is equivalent to a 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 air 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 non-blocked state, then the increase rate 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 blocked, it is judged that there is no blockage or partial blockage but no automatic cleaning is required.

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

[0019] S1: Obtain the lower limit of the flow resistance increase rate 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 completed; 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; 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 deriving

[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 cytometer for ultrasonic cleaning.

[0028] Furthermore, the flow resistance of the nozzle in the non-blocked state is This is the state of a brand new nozzle when it is used for the first time or after the nozzle has 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 a flow cytometer is the system parameter.

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

[0031] Compared with the existing technology, the flow cytometer nozzle clogging 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 fluid output pipeline, and analyzes the nozzle clogging status through pressure detection of the flow chamber. To facilitate the evaluation of the flow resistance of each component in the liquid path, a flow meter is connected between the sheath fluid flow path and the droplet generator flow path. According to the flow path-circuit equivalence principle, the flow path from the sheath fluid tube inlet to the nozzle outlet is circuit-equivalent, and the flow resistance of each component in the liquid path is calculated. The increase ratio of the nozzle flow resistance at time t is calculated. The nozzle clogging condition and whether automatic cleaning is possible are judged based on the error limit and the increase ratio of the nozzle flow resistance. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0033] Figure 2 Schematic diagram of the flow cell sorter nozzle blockage monitoring and cleaning method of the present invention;

[0034] Figure 3 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 This is the equivalent circuit diagram when the nozzle is inserted and the A position and B position of the three-way two-position valve are connected;

[0036] Figure 5 This is the 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 path; 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 chamber; 43, flow chamber; 44, nozzle; 50, flow meter. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall 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 commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated 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] Build a flow cytometer, connect the air supply path with the sample path and the sheath liquid path, connect the sample path and the sheath liquid path 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;

[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 a flow cytometer

[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 state of the flow cell sorter, 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 cytometer, the flow resistance element is disabled by a control valve, and the sheath liquid flow rate Q1 is collected from the flow meter; the nozzle is removed from the flow cytometer, the flow resistance element is enabled by a control valve, and the sheath liquid flow rate Q2 is collected from the flow meter; the nozzle is installed in the flow cytometer, the flow resistance element is enabled by a control valve, and the sheath liquid flow rate Q3 is collected from the flow meter;

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

[0049]

[0050] 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 air pressure in the sheath fluid 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 and cannot be cleaned automatically; and When the nozzle is blocked, it can automatically clean it; when When the nozzle is blocked, it is judged that there is no blockage or partial blockage 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 circuit 10, a sample circuit 20, a sheath liquid circuit 30, and a droplet generation circuit 40. The sample circuit 20 and the sheath liquid circuit 30 are respectively connected to the air supply circuit 10. The air supply circuit 10 drives the sample in the sample circuit 20 and the sheath liquid in the sheath liquid circuit 30. The sample circuit 20 and the sheath liquid circuit 30 are connected to the droplet generation circuit 40. The sample in the sample circuit 20 and the sheath liquid in the sheath liquid circuit 30 enter the droplet generation circuit 40 to generate droplets.

[0054] The air supply circuit 10 comprises a compressor 11, a filter 12, a mist separator 13, a pressure reducing valve 14, and an air tank 15, connected in sequence. A safety valve 16 is mounted on the air tank 15. The pressure reducing valve 14 is used to initially regulate the output pressure of the compressor 11, which can be adjusted manually or electrically. This output pressure is typically set to 1.2 to 2 times the maximum supply pressure in the sheath fluid flow path 30, but not exceeding the maximum allowable input pressure of the first and second electrical proportional valves 21 and 31. The air tank 15 stores the compressed gas after the pressure reduction by the pressure reducing valve 14. The safety valve 16 ensures the safety of the air supply pressure at its downstream end. The safety valve 16 can be a pressure switch with a built-in contact spring. When the pressure in the air tank 15 exceeds 80% to 100% of the maximum allowable input pressure of the first or second electrical proportional valves 21 and 31, the safety valve 16 automatically opens and releases air, reducing the pressure in the air tank 15 to the set value. Otherwise, the safety valve 16 remains closed.

[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. A first liquid level gauge 26 is installed in 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 equipped with a first liquid level gauge 26, which is a capacitive level gauge and is used for sample transmission and monitoring the liquid level of the sample in the sample tube 24.

[0056] The sheath fluid flow path 30 includes a second electrical proportional valve 31, a second pressure gauge 32, a control valve 36 for the sheath fluid barrel 33, and a flow resistance element 35, which are sequentially connected. A second liquid level gauge 34 is mounted on the sheath fluid barrel 33. The second electrical proportional valve 31 is used to adjust the air pressure in the sheath fluid 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 fluid barrel 33 to drive the sheath fluid with positive pressure; the second liquid level gauge 34 is mounted on the sheath fluid barrel 33 to monitor the sheath fluid level. The control valve 36 is a three-way, two-position valve. When positions A and B are connected, the flow resistance element 35 is inactive, and the flow cytometer is in a cleaning state. When positions A and C are connected, the flow resistance element 35 is active, and the flow cytometer is in an analysis or sorting state. The flow resistance element 35 is a throttle valve or an elongated tube. In this embodiment, a microporous throttle valve is used as the flow resistance element 35. The flow resistance element 35 is installed in the sheath fluid output pipeline to increase the flow resistance of the entire flow path. The third pressure gauge 41 detects the pressure of the flow chamber 42 to analyze the blockage state of the nozzle 44. The second liquid level sensor 34 is preferably a float-type or ultrasonic continuous liquid level sensor.

[0057] The droplet generation flow path 40 includes a flow chamber 42, a flow cell 43, and a nozzle 44, which are connected in sequence. A third pressure gauge 41 is mounted on the flow chamber 42. The flow chamber 42 in the droplet generation flow path 40 is used for three-dimensional hydrodynamic focusing of the sample. After the sheath fluid and sample flow into the flow chamber 42, the sheath fluid envelops 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 cytometry 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 between 70 and 130 μm, and is used to generate droplets of stable size.

[0058] The upper limit of the nozzle flow resistance increase ratio and the limiting rate of change of pressure in the flow chamber of a flow cytometer 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 equivalent to the circuit according to the flow path-circuit equivalence principle. Among them, (1) when the nozzle 44 is plugged in and the A position and 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 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. And according to formula (2), the pressure in the flow chamber at time t is calculated relative to the pressure in the flow chamber 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. This is the default setting of the instrument and can be confirmed based on the actual operation of the instrument. The completely unblocked state is generally the default state when a new nozzle 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 rate η(t) of the flow resistance of the nozzle 44 at time t is derived:

[0070]

[0071] When using the i-th type 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 ratio of the i-th type nozzle 44.

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

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

[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 cytometer 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 completed; 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 and ultrasonically cleaned.

[0078] Compared with the prior art, the flow cytometer nozzle clogging monitoring and cleaning method of the present invention increases the flow resistance of the entire flow path by connecting a flow resistance element 35 to the sheath liquid output pipeline, and analyzes the nozzle clogging status through pressure detection 42 of the flow chamber. 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, and the flow resistance of each component in the liquid path is calculated. The increase ratio of the nozzle 44 flow resistance at time t is calculated. The clogging condition of the nozzle 44 and whether it can be automatically cleaned are judged based on the error limit and the increase ratio of the nozzle flow resistance.

[0079] The above embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patented invention. It should be noted that those skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention. These variations and improvements are equivalent modifications and improvements to the above embodiments based on the essential technology of the present invention and fall within the scope of protection of the present invention.

Claims

1. A flow cell sorter nozzle clogging monitoring and cleaning method, characterized in that: The following steps are involved: A flow cytometer is constructed, the flow cytometer comprising an air supply path, a sample path, a sheath fluid path, and a droplet generation path, wherein the sample path and the sheath fluid path are respectively connected to the air supply path, the air supply path drives the sample in the sample path and the sheath fluid in the sheath fluid path, the sample path and the sheath fluid path are connected to the droplet generation path, the sample in the sample path and the sheath fluid in the sheath fluid path enter the droplet generation path to generate drops, the sheath fluid path comprises a sheath fluid barrel, a control valve, and a flow resistance element that are connected in sequence, the flow resistance element is installed in the sheath fluid output pipeline to increase the flow resistance of the entire path, and the droplet generation path comprises a flow chamber, a flow chamber, and a nozzle that are connected in sequence; Get the upper limit of the nozzle flow resistance increase factor and the limiting rate of change of pressure in the flow chamber of a flow cytometer ; The nozzle is installed in the flow cell sorter, and the pressure in the flow 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, real-time pressure in the flow 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 cytometer, the flow resistance element is disabled by the control valve, and the sheath liquid flow rate Q1 of the flow meter is collected; the nozzle is removed from the flow cytometer, the flow resistance element is activated by the control valve, and the sheath liquid flow rate Q2 of the flow meter is collected; the nozzle is installed in the flow cytometer, the flow resistance element is activated by 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 a circuit, and the following is obtained: Formula 1, Formula 2, Formula 3, in, is the flow resistance of the nozzle; is the flow resistance of the flow chamber and flow cavity, is the flow resistance of the flow resistance element; It is the driving air pressure in the sheath fluid barrel; Calculate according to formula 1, formula 2 and formula 3 as well as ,make , , For the Nozzle models, is the flow resistance of the nozzle in the non-blocked state, then the increase rate 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 automatically cleaned; when When the nozzle is blocked, it is judged that there is no blockage or partial blockage but no automatic cleaning is required.

2. The flow cytometer nozzle clogging monitoring and cleaning method according to claim 1, characterized in that: when and When the automatic cleaning steps are as follows: S1: Obtain the lower limit of the flow resistance increase rate 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 ; S4: When When , the automatic cleaning ends; when > When , return to step S2 until .

3. The flow cytometer nozzle clogging monitoring and cleaning 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 flow cytometer nozzle clogging monitoring and cleaning method according to claim 3, characterized in that: 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. When position A is connected to position C, the flow resistance element works.

5. The flow cytometer nozzle clogging monitoring and cleaning method according to claim 1, characterized in that: According to the equivalent circuit diagram, we can get , thus deriving .

6. The flow cytometer nozzle clogging monitoring and cleaning method according to claim 1, characterized in that: The flow resistance element is a throttle valve or a slender tube.

7. The flow cytometer nozzle clogging monitoring and cleaning method 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 cytometer for ultrasonic cleaning.

8. The flow cytometer nozzle clogging monitoring and cleaning method according to claim 1, characterized in that: The flow resistance of the nozzle in the non-clogging 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 flow cytometer nozzle clogging monitoring and cleaning method according to claim 1, characterized in that: The upper limit of the flow resistance increase ratio of the nozzle and the limiting rate of change of pressure in the flow chamber of a flow cytometer is the system parameter.

10. The flow cytometer nozzle clogging monitoring and cleaning method according to claim 1, characterized in that: The nozzle aperture is 70 to 130 μm.

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