Droplet dispensing monitoring system

Abstract

The invention discloses a liquid drop distribution monitoring system, which abandons a traditional light shielding detection mode, adopts an EC (charge detector induction detection) method, captures mirror image charge signals generated by charged liquid drops by arranging a charge detector consisting of a plurality of groups of induction electrodes at key positions of a liquid drop flight path, and transmits the mirror image charge signals to the liquid drop distribution monitoring system. And the charge state and the spatial position of the liquid drop can be accurately obtained. The system effectively solves the problems that an optical system in the prior art is complex, needs frequent calibration and is easily interfered by ambient light, and has the advantages of high environmental adaptability, good stability, accurate detection, simple and convenient maintenance and the like.

Description

Technical Field

[0001] This invention relates to the field of flow cytometry cell sorting, and more particularly to a droplet distribution monitoring system. Background Technology

[0002] The Side Stream Monitor system uses a light-blocking detection method to monitor the liquid flow and droplets. When the light source is blocked by the liquid flow and droplets, a shadow is formed. When this shadow falls on the photodiode (PD), the photocurrent of the photodiode changes. The droplet can be identified based on this change in photocurrent. It monitors each charging droplet, ensuring that the deflection angle of each droplet is within a set range, thus automating the flow cytometry cell sorting module. This automates the previously manual adjustments to the piezoelectric drive voltage, droplet charging voltage, and droplet charging phase, maintaining stable liquid flow and breakpoint positions. It can also automatically monitor nozzle blockage and stop the sorting process promptly.

[0003] The optical system of light-blocking detection is highly complex, requiring precise alignment of the light source, liquid flow, and photodetector. Installation and debugging are complicated, and each nozzle change, liquid flow adjustment, or even minor vibration can cause optical path misalignment, necessitating frequent calibration. It is also sensitive to ambient light and easily affected by interference; changes in the laboratory environment and lighting can influence the detection signal. Summary of the Invention

[0004] This invention provides a droplet monitoring system with stronger environmental adaptability, higher signal-to-noise ratio, and faster response speed.

[0005] This application provides a droplet distribution monitoring system, including a droplet generating module for dividing a continuous liquid flow into droplets; a charging module for charging the droplets; and multiple charge detectors, each of which includes multiple sensing electrodes, the multiple charge detectors being positioned along the flight path of the droplets; the multiple charge detectors being used to detect the charge state and spatial position of the droplets at the specified locations.

[0006] In some embodiments, the plurality of charge detectors includes: a first detector disposed on the center path of the droplet when it is not deviated, which generates a first charge pulse T1 if it detects a charged droplet; and a processor for recording the initial charging time T0 of the droplet and monitoring whether there is a charge pulse within a set first time window. If so, it is determined that the disconnection position between the charged droplet and the liquid flow is stable; otherwise, an abnormality is indicated. The first time window is T0 + M ± δ1, where δ1 < 1 / 32 of the droplet period and M is a fixed constant.

[0007] In some embodiments, the monitoring system further includes at least one second detector disposed on the deflection path of the droplet. If a charged droplet is detected, a second charge pulse T2 is generated. A deflection electric field module is used to generate a deflection electric field, under which the droplet deflects. The processor is used to record the initial charging time T0 of the droplet and monitor whether there is a charge pulse within a set second time window. If so, it is determined that the deflection angle of the charged droplet is correct; otherwise, an abnormality is indicated. The second time window is T0 + Q ± δ2, where δ2 < 1.5 droplet cycles and Q is a fixed constant.

[0008] In some embodiments, the monitoring system further includes a third detector for determining the charging phase and charging voltage in a calibration scenario; a charging module for charging a single droplet with a fixed first voltage, the first voltage being less than a set value; a processor for controlling the charging module to gradually increase the charging phase and charging voltage to deflect the droplet; the third detector detecting that the charged droplet can generate a charge pulse, the amplitude of which changes with the increase of the charging voltage and charging phase, and determining the ideal charging phase and ideal voltage corresponding to when the amplitude of the charge pulse reaches its maximum.

[0009] In some embodiments, the third detector is further configured to determine whether the core module of the distribution system has malfunctioned in the unsorted state based on the presence or absence of the detected charge pulse and whether the charge pulse is stable.

[0010] In some embodiments, a fourth detector is further included, which is disposed on a first offset path of the droplet, and a third detector is disposed on a second offset path of the droplet. The first offset path is on one side of the central path, and the second offset path is on the other side of the central path. The vertical distance between the first detector and the droplet emission module is greater than the distances between the third detector and the fourth detector and the droplet emission module. The processor determines whether the liquid flow has bifurcation based on the first detector, the third detector, and the fourth detector.

[0011] In some embodiments, the processor controls the charging module to turn off the high voltage and charge the droplet, and records the pulse time T0 of any one of the first detector, the third detector and the fourth detector that generates a pulse, and monitors whether the first detector, the third detector and the fourth detector all generate charge pulses within a set third time window. If so, it is confirmed that a bifurcation phenomenon has occurred.

[0012] In some embodiments, the time interval between the flight of the third detector and the first detector is τ, and the third time window is T0+3τ.

[0013] In some embodiments, the presence of a first anomaly, namely nozzle blockage, is determined based on the detection signals from the first detector, the second detector, the third detector, and the fourth detector.

[0014] In some embodiments, there are four second detectors, with two second detectors disposed on one side of the central path and the other two second detectors disposed on the other side of the central path. The offset angle between the second detectors and the central path is greater than the offset angle between the third detector and the fourth detector and the central path.

[0015] The droplet distribution monitoring system of this application detects droplet distribution through pulse detection signals. The time resolution and amplitude resolution of the charge pulse signal are higher than those of the photocurrent change signal, making it more sensitive to droplet detection. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram showing the installation locations of each charge detector.

[0018] Figure 2 A flowchart for determining the stability of the droplet and liquid flow disconnection location.

[0019] Figure 3 A flowchart for determining the deflection angle of the charging droplet.

[0020] Figure 4 A flowchart for detecting small-angle deflection of droplets in a calibration scenario.

[0021] Figure 5 A flowchart for detecting fluid flow bifurcation faults. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The technical solution of the present invention will be described in detail below with reference to specific embodiments. The modules of the droplet distribution monitoring system of the present invention are electrically connected and cooperate, and the charge detectors are arranged in preset positions. The processor realizes full-dimensional monitoring and control by receiving the charge pulse signals of each detector. The functions of each module, the detector layout and the specific monitoring process will be explained one by one below.

[0024] I. Overall System Composition and Functions of Each Module Droplet generation module: Used to divide a continuous liquid flow into discrete droplets of uniform size and frequency, it is the basic unit for droplet distribution; it has a built-in piezoelectric drive structure, which controls the splitting rhythm of the liquid flow through a piezoelectric drive sine wave, and the piezoelectric drive voltage can be adjusted by the processor according to the calibration results.

[0025] Charging module: It is set up corresponding to the liquid outlet of the droplet generating module and is used to charge the discrete droplets after the droplet generating module is divided. The charge of the droplet is determined by the charging voltage and the charging time is controlled by the charging phase. Both the charging voltage and the charging phase can be adjusted in real time by the processor.

[0026] Deflection electric field module: includes a high-voltage plate assembly, used to apply high voltage to form a deflection electric field; after the charged droplet enters the deflection electric field, it undergoes angular deflection under the action of electric field force. The on / off state of the high-voltage plate and the voltage value are controlled by the processor. When the high-voltage plate is not energized, the deflection electric field disappears, and the droplet flies in a straight line along the central path.

[0027] Charge detector array: includes at least one charge detector, and in one embodiment includes at least one of core detector EC, L2 / L1 / R1 / R2 drop detector EC, test detector EC, and fanning detector EC.

[0028] Each charge detector contains multiple sensing electrodes and is a charge-inductive detector. When a charged droplet passes through the detection area of ​​the detector, the sensing electrodes sense the charge of the droplet and generate a charge pulse signal, which is then transmitted to the processor. When no charged droplet passes through any detector, no charge pulse signal is output.

[0029] The processor is the control core of the system, with built-in time recording, signal analysis, and parameter control modules. It can record the droplet charging time and the charge pulse detection time of each detector. In some embodiments, it analyzes the presence, amplitude, and occurrence time of charge pulses. In other embodiments, it adjusts the piezoelectric driving voltage of the droplet generation module, the charging voltage and charging phase of the charging module based on the analysis results, controls the power supply of the deflection electric field module, and issues fault warnings when an anomaly is detected, etc.

[0030] As shown Figure 1 in the figure, the installation positions and layout requirements of each charge detector In some embodiments, the charge detector includes a core detector EC (first detector): precisely set on the central flight path when the droplet is not deflected, that is, the straight flight path of the droplet when the deflection electric field disappears. Its vertical distance H2 from the droplet generation module is the largest among all detectors in terms of the vertical distance from the droplet generation module.

[0031] In some other embodiments, the charge detector includes a drop detector EC (second detector): there are four in total, divided into a left group and a right group. The left group includes an L2 drop detector EC and an L1 drop detector EC, and the right group includes an R1 drop detector EC and an R2 drop detector EC, which are respectively set on the droplet deflection paths on both sides of the central path; the deflection angles of the four drop detector ECs with respect to the central path are all greater than those of the test detector EC and the fanning detector EC, adapting to the detection requirements of large-angle deflection of droplets to both sides, and are used to detect whether the angles of the droplets deflected in different directions meet the set requirements.

[0032] In some embodiments, the charge detector includes a test detector EC (third detector): set on the second deflection path on one side of the central path, with a vertical distance H1 (H1 < H2) from the droplet generation module. Its deflection angle with respect to the central path is smaller than that of the drop detector EC, adapting to the detection requirements of small-angle deflection of droplets in the calibration scenario.

[0033] In some other embodiments, the charge detector includes a fanning detector EC (fourth detector): set on the first deflection path on the other side of the central path, with the same vertical distance from the droplet generation module as the test detector EC. Its deflection angle with respect to the central path is smaller than that of the drop detector EC and does not coincide with the central path. Only when the liquid flow bifurcates, the charged droplets will spread to its detection area.

[0034] In some embodiments, as Figure 2 shown in the figure, the detection process for the stability of the droplet disconnection position is as follows: This process is implemented by the core detector EC in cooperation with the processor, and is used to determine whether the disconnection position between the charged droplet and the liquid flow is stable, which is the basis for the precise deflection of the droplet. The specific steps are as follows: The processor controls the high-voltage plate of the deflection electric field module to be de-energized, shutting off the deflection electric field and causing the charged droplet to fly in a straight line along the central path. The processor controls the charging module to charge the droplet, recording the initial charging time of the droplet as T0. When the charged droplet flies along the central path to the detection area of ​​the core detector EC, the core detector EC senses the charge and generates the first charge pulse, transmitting the pulse signal to the processor, which records the pulse detection time as T1. The processor calculates the time interval ΔT = T1 - T0 and compares ΔT with a preset fixed constant M, while monitoring whether ΔT falls within the set first time window (T0 + M ± δ1), where δ1 < 1 / 32 of the droplet period. If ΔT falls within the first time window, the processor determines that the disconnection position between the charged droplet and the liquid flow is stable. If ΔT exceeds the first time window, the processor determines that the disconnection position is unstable and issues an abnormal warning. At the same time, it can adjust the liquid flow rate of the droplet generation module to restore the disconnection position to stability.

[0035] In some embodiments, such as Figure 3 As shown, the droplet deflection angle detection process is as follows: This process is implemented by four drop detector ECs in conjunction with a deflection electric field module and a processor. It is used to determine whether the actual deflection angle of the charging droplet is the set angle. The specific steps are as follows: The processor controls the high-voltage board of the deflection electric field module to be energized, forming a deflection electric field of a set intensity, while simultaneously controlling the droplet generation module and the charging module to enter a stable working state.

[0036] The processor controls the charging module to charge the droplet, and records the initial charging time of the droplet as T0; After being charged, the droplet enters the deflection electric field and undergoes an angular deflection, flying along a preset deflection path. If the deflection angle meets the set requirements, the droplet will fly precisely to the detection area of ​​the drop detector EC at the corresponding position. The drop detector EC senses the charge and generates a second charge pulse, which is transmitted to the processor. The processor records the pulse detection time as T2.

[0037] The processor calculates the time interval ΔT = T2 - T0 and compares ΔT with a preset fixed constant Q. At the same time, it monitors whether ΔT falls within the set second time window (T0 + Q ± δ2), where δ2 < 1.5 droplet cycles.

[0038] If ΔT falls within the second time window, the processor determines that the droplet deflection angle is correct; if ΔT exceeds the second time window, the processor determines that the deflection angle is abnormal and issues a warning. In some embodiments, while issuing the alarm, the voltage of the high-voltage plate of the deflection electric field module or the charging voltage of the charging module can be adjusted to restore the droplet deflection angle to the set value.

[0039] Furthermore, the L2 / L1 drop detector EC detects different deflection angles on the left side of the center path, and the R1 / R2 drop detector EC detects different deflection angles on the right side of the center path, enabling multi-directional and multi-angle deflection detection of droplets to adapt to different distribution / sorting requirements.

[0040] In some embodiments, such as Figure 4 As shown, an automatic calibration process for charging phase and charging voltage is provided. This process is implemented by a test detector EC in conjunction with a droplet generation module, a charging module, and a processor. It is used to automatically find and determine the ideal charging phase and charging voltage after system initialization and fault recovery. The specific steps are as follows: After system initialization or fault recovery, the processor controls the liquid flow stabilization unit to work, so that the liquid flow of the droplet generation module enters a stable state, and at the same time controls the high voltage plate of the deflection electric field module to be energized to form a low-intensity deflection electric field. The processor controls the charging module to charge a single droplet at a fixed first voltage, which is less than the system set value, to ensure that the droplet deflection angle is small and can be collected by the waste liquid collector; The processor controls the charging module to gradually increase the charging phase, so that the charging time of the droplet changes with the phase of the piezoelectric driving sine wave. When the charged droplet deflects to the detection area of ​​the test detector EC, the test detector EC generates a charge pulse and transmits it to the processor. After detecting a charge pulse, the processor controls the charging module to fine-tune the charging voltage while continuing to gradually increase the charging phase. It also receives the charge pulse signal from the test detector EC in real time and analyzes the pulse amplitude. When the processor detects that the amplitude of the charge pulse has reached its maximum value, it immediately stops adjusting the charging phase and voltage, determines the corresponding charging phase as the ideal charging phase and the corresponding charging voltage as the ideal charging voltage, and sends these parameters to the charging module as reference parameters for subsequent droplet charging.

[0041] In some embodiments, a core module fault detection process is provided in an unsorted state. This process is implemented by a test detector EC in conjunction with a processor. It is used to detect the working status of the system's core modules (Sort modules, including charging modules, deflection electric field modules, and droplet generation modules) in a standby state where the system has no allocation / sorting operations. The specific steps are as follows: When the system is in an unsorted standby state, the processor controls the droplet generating module to maintain a stable liquid flow; The processor controls the charging module to charge the droplet at regular intervals, and controls the deflection electric field module to deflect the droplet to the detection position of the test detector EC. The processor receives the charge pulse signal from the test detector EC in real time and analyzes the presence and amplitude of the pulse signal. If the test detector EC can continuously detect charge pulses of stable amplitude, the processor determines that the core module of the system is working normally; if no charge pulses are detected, or if the pulse amplitude fluctuates abnormally, the processor determines that the core module has failed and issues a fault warning to prompt staff to troubleshoot the problem.

[0042] In some embodiments, such as Figure 5 As shown, a flow bifurcation detection process is provided. This process is implemented by a core detector EC, a test detector EC, a fanning detector EC, a charging module, and a processor to determine whether the central flow has bifurcation (rainfall phenomenon). The specific steps are as follows: The processor controls the high-voltage board of the deflection electric field module to shut off the high voltage, and at the same time controls the charging module to charge the droplet, so that the charged droplet flies along the central path; When any one of the core detector EC, test detector EC, or fanning detector EC detects a charged droplet and generates a charge pulse, the processor records the initial time of the pulse as T0. The processor uses T0 as a reference to monitor whether the core detector EC, test detector EC, and fanning detector EC can all detect charge pulse signals within the set third time window (T0+3τ). If all three detectors generate charge pulses within the third time window, the processor determines that the liquid flow has bifurcated; if any detector does not detect a charge pulse, the processor determines that the liquid flow has not bifurcated and is working normally. Furthermore, the one-way flight time of the droplet from the installation height H1 of the test detector EC to the installation height H2 of the core detector EC is defined as τ. This parameter is the core time reference for the processor to determine the liquid flow bifurcation phenomenon, and is pre-calibrated and stored by the system according to the liquid flow velocity.

[0043] In some embodiments, a nozzle clogging fault detection process is provided. This process is implemented by a core detector EC, four drop detector ECs, a test detector EC, and a fanning detector EC in conjunction with a processor. It is used to determine whether the nozzle of the droplet generation module is clogged. The specific steps are as follows: The processor control system enters normal working state and controls the power supply of the charging module and the deflection electric field module according to the detection requirements, so that the droplet flies along the preset path; The processor simultaneously receives detection signals from the core detector EC, four drop detector ECs, the test detector EC, and the fanning detector EC, and analyzes the signal acquisition status of each detector. If all detectors continuously output no charge pulse signal, and the droplet generation module is in normal working condition, the processor determines that the nozzle is blocked (first anomaly) and immediately issues an early warning. At the same time, the control system stops the sorting / distribution operation to avoid damage caused by the equipment running idle. If some detectors can detect charge pulse signals, only the abnormality of the liquid flow / droplet in the corresponding detection path is determined, and it is not determined to be nozzle blockage.

[0044] It should be noted that the functions or steps that can be implemented by the computer-readable storage medium or computer device described above can be referred to the relevant descriptions on the server side and client side in the foregoing method embodiments. To avoid repetition, they will not be described one by one here.

[0045] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0046] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0047] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A droplet distribution monitoring system, characterized in that, The droplet generation module is used to divide a continuous liquid flow into droplets; A charging module for charging the droplets; Multiple charge detectors, each of which includes multiple sensing electrodes, are disposed along the flight path of the droplet; Multiple charge detectors are used to detect the charge state and spatial position of the droplets at the location.

2. The distribution system according to claim 1, characterized in that, The plurality of charge detectors include: a first detector, which is disposed on the center path of the droplet when it is not deflected, and which can generate a first charge pulse T1 if it detects a charged droplet; It also includes a processor for recording the initial charging time T0 of the droplet and monitoring whether there is a charge pulse within a set first time window. If so, it determines that the disconnection position between the charging droplet and the liquid flow is stable; otherwise, it indicates an abnormality. The first time window is T0+M±δ1, where δ1<1 / 32 of the droplet period and M is a fixed constant.

3. The distribution system according to claim 2, characterized in that, The monitoring system also includes at least one second detector, which is disposed on the deflection path of the droplet. If a charged droplet is detected, a second charge pulse T2 can be generated. The deflection electric field module generates a deflection electric field, under which the droplet deflects. The processor is used to record the initial charging time T0 of the droplet and monitor whether there is a charge pulse within a set second time window. If so, it determines that the deflection angle of the charging droplet is correct; otherwise, it indicates an abnormality. The second time window is T0 + Q ± δ2, where δ2 < 1.5 droplet cycles and Q is a fixed constant.

4. The distribution system according to claim 3, characterized in that, The monitoring system also includes a third detector for determining the charging phase and charging voltage in a calibration scenario; The charging module and the electric field deflection module are used to charge a single droplet with a fixed first voltage, the first voltage being less than a set value. The processor controls the charging module to gradually increase the charging phase and charging voltage to deflect the droplet; The third detector detects that the charged droplet can generate charge pulses. The amplitude of the charge pulses changes with the increase of the charging voltage and the charging phase. The ideal charging phase and ideal voltage corresponding to the maximum amplitude of the charge pulses are determined.

5. The distribution system according to claim 4, characterized in that, The third detector is also used to determine whether the core module of the distribution system has malfunctioned in the unsorted state, based on the presence or absence of the detected charge pulse and whether the charge pulse is stable.

6. The distribution system according to claim 5, characterized in that, It also includes a fourth detector, which is disposed on the first offset path of the droplet, and a third detector, which is disposed on the second offset path of the droplet. The first offset path is on one side of the central path, and the second offset path is on the other side of the central path. The vertical distance between the first detector and the droplet emission module is greater than the distances between the third and fourth detectors and the droplet emission module. The processor determines whether the liquid flow has bifurcation based on the first detector, the third detector, and the fourth detector.

7. The droplet distribution monitoring system according to claim 6, characterized in that, The processor controls the charging module to turn off the high voltage and charge the droplet, and records the pulse time T0 of any one of the first detector, the third detector and the fourth detector. It also monitors whether the first detector, the third detector and the fourth detector all generate charge pulses within a set third time window. If so, it confirms that a bifurcation phenomenon has occurred.

8. The droplet distribution monitoring system according to claim 7, characterized in that, The time interval between the flight of the third detector and the first detector is τ, and the third time window is T0+3τ.

9. The droplet distribution monitoring system according to claim 8, characterized in that, Based on the detection signals from the first detector, the second detector, the third detector, and the fourth detector, it is determined whether there is a first anomaly, which is nozzle blockage.

10. The droplet distribution monitoring system according to claim 9, characterized in that, There are four second detectors, two of which are located on one side of the central path and the other two are located on the other side of the central path. The offset angle between the second detectors and the central path is greater than the offset angle between the third detector and the fourth detector and the central path.

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