Liquid drop sorter based on fluorescence detection

Abstract

According to the liquid drop sorting instrument based on fluorescence detection, an inverted microscope serves as a whole instrument base and is located at the bottom, an XY precise moving platform is fixed to the microscope, a z-axis moving platform is fixed to a simple supporting frame beside the microscope, a fluorescence channel is installed on the z-axis moving platform, and a microfluidic liquid drop sorting module is fixed to the tip end of the fluorescence channel. A fluorescence detection module is arranged on the side wall of the fluorescence channel, the fluorescence detection module and the microfluidic liquid drop sorting module are both connected with the signal end of the FPGA signal processing module, the fluorescence detection module and the microfluidic liquid drop sorting module are controlled through the FPGA, the condition of generated liquid drops is observed through a microscope, the sorting process of the liquid drops is dynamically adjusted, and the quality of the liquid drops is improved. The closed-loop control of fluorescent liquid drop sorting is realized; according to the invention, high-precision and high-throughput liquid drop sorting can be realized, the liquid drop screening efficiency is greatly improved, the target liquid drop can be accurately identified and selected, and the method can be widely applied to the fields of high-throughput screening, single cell analysis, enzyme evolution, drug discovery and the like.

Description

Technical Field

[0001] The invention relates to the technical field of droplet microfluidics, and in particular to a droplet sorter based on fluorescence detection. Background Art

[0002] Droplet microfluidics technology is widely used in research such as chemistry, proteomics, and genomics due to its advantages such as high throughput, low consumption, and precise control. However, the efficiency and accuracy of the droplet sorting process have always been one of the bottlenecks restricting the application of this technology. Although the existing sorting methods can achieve rapid sorting of droplets, there are still problems such as low sorting accuracy, complex equipment, and limited processing speed.

[0003] Traditional fluorescent droplet sorting, such as the article "Single-cell analysis and sorting using droplet-based microfluidics" published in "Nature Protocols, 2013-May-01", details the use of droplet-based microfluidics for single-cell analysis and sorting. The droplet-based sorting mentioned uses a droplet-based microfluidics solution, and the compartmentalization of single cells in the droplets can analyze the proteins released or secreted by the cells. However, the sorting accuracy is limited, and the intensity and stability of the fluorescent signal are easily affected by background noise, droplet size changes, and optical system drift, which may lead to missorting.

[0004] Fluorescence-activated droplet sorting (FADS) is usually expensive and complicated to operate. For example, the patent application with publication number WO2025050133A1, entitled Separation and Amplification of Natural Killer Cells Using Fluorescence-activated Droplet Sorting Technology, discloses a fluorescence-activated droplet sorting system based on high-throughput microfluidics. The system is complex and expensive, and the operation is cumbersome, making it difficult to meet the needs of high-throughput screening. Therefore, optimizing the optical detection system and improving droplet stability and sorting efficiency are key directions for the development of FADS technology. Summary of the invention

[0005] In order to overcome the above-mentioned problems of the prior art, the purpose of the present invention is to propose a droplet sorter based on fluorescence detection, which can achieve high-precision and high-throughput droplet sorting by controlling rapid fluorescence signal detection and droplet sorting through FPGA, greatly improving the droplet screening efficiency, and can accurately identify and select target droplets. It can be widely used in high-throughput screening, single-cell analysis, enzyme evolution, drug discovery and other fields.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] Fluorescence detection based droplet sorter, including:

[0008] Microscope 1, inverted as the base of the entire instrument at the bottom, is used to observe the state of the generated droplets; it provides an observation source for the setting of human-computer interaction parameters in the FPGA signal processing module 5;

[0009] The XY precision moving platform 2 is fixed in the groove of the side wall of the microscope 1 and is used for initial position correction of the microfluidic sorting module 3;

[0010] A z-axis moving platform 6 is arranged next to the microscope 1 and is used for initial position correction of the microfluidic sorting module 3;

[0011] The fluorescent passage 4-1 is a transparent pipe in the light source irradiation direction installed on the z-axis moving platform 6, and the fluorescent detection module 4 is installed on its side wall;

[0012] The microfluidic droplet sorting module 3 is fixed at the tip of the fluorescent channel 4-1; the surface is designed with microchannels to achieve droplet sorting;

[0013] Fluorescence detection module 4, which generates fluorescence signals after irradiating the droplets and then converts them and sends them to FPGA signal processing module 5;

[0014] The FPGA signal processing module 5 realizes signal transmission and processing, and controls the droplet sorting of the microfluidic droplet sorting module 3 .

[0015] The microfluidic droplet sorting module 3 is made of polydimethylsiloxane (PDMS) and has a microfluidic channel on its surface. The channel at the sorting junction near the sorting electrode 3-2 is arc-shaped, and the two ends of the arc are respectively connected to the inlet pipe 3-1 and the outlet pipe 3-3. The sorting electrode 3-2 is in a pointed triangle shape at the arc-shaped channel. The sorting electrode 3-2 is connected to the high-voltage amplifier 3-4; the high-voltage amplifier 3-4 is connected to the FPGA signal processing module 5 through the DAC pulse signal conversion module 5-1.

[0016] The fluorescence detection module 4 includes a photomultiplier tube 4-3 and an optical fiber 4-4 fixed on the side wall of the fluorescence path. After the excitation light source 4-2 irradiates the droplet, the excited fluorescent molecules generate a fluorescence signal which is transmitted through the optical fiber 4-4 and enters the photomultiplier tube 4-3. The photomultiplier tube 4-3 converts the light signal into an electronic signal and transmits it to the FPGA signal processing module 5. 。

[0017] The FPGA signal processing module 5 includes a host computer and a slave computer part, the slave computer includes an ADC data acquisition module 5-2, a main control module 5-3 and an Ethernet communication module 5-4; the signal end of the ADC data acquisition module 5-2 is connected to the photomultiplier tube 4-3, and the received analog signal is converted into a digital signal that can be processed by the main control module 5-3. The collected fluorescence signal is buffered by the ADC data acquisition module 5-2 and called by the main control module 5-3; the Ethernet communication module 5-4 transmits the signal to the Ethernet communication interface 5-6 of the host computer. The host computer part is implemented on the PC side, and the signal transmitted from the Ethernet communication interface 5-6 is parameterized and visualized in the visualization module and parameter setting module of the human-computer interaction interface 5-5.

[0018] The main control module 5-3 realizes real-time detection of the collected signal and control of the sorting pulse; the collected fluorescence signal is first denoised by mean filtering and baseline drift correction is performed; then the main control module 5-3 detects the intensity and duration of the processed signal to determine whether a droplet has passed through the microfluidic channel and whether the passing droplet is a target single-cell droplet; then the main control module 5-3 sends a pulse control signal according to the detection result at the current moment. If the target single-cell droplet is detected passing, the main control module 5-3 sends a pulse signal, and the DAC pulse signal conversion module 5-1 converts the digital signal into an analog signal and inputs it into the power amplifier 3-4; then the power amplifier 3-4 amplifies the sorting pulse signal and transmits it to the sorting electrode 3-2 in the microfluidic droplet sorting module.

[0019] In the upper computer part of the FPGA signal processing module 5, the human-computer interaction interface 5-5 includes a visualization module and a parameter setting module. The parameter setting module is responsible for realizing the settings of four-way PMT gain, four-way channel selection, droplet signal intensity threshold, target single-cell droplet signal intensity threshold and duration threshold, sorting pulse high and low levels, sorting pulse duration, and sorting pulse delay time; enabling the lower computer to process single-cell droplet sorting control under different conditions; the data visualization module is used to receive the fluorescence signal, droplet signal duration, and droplet maximum signal intensity data processed by the lower computer; and then the upper computer periodically refreshes the received lower computer signal so that the user can realize accurate sorting parameter settings according to the detection signal.

[0020] A high-speed CCD camera 4-5 is installed at the end of the fluorescent channel to monitor the entire sorting process in real time.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The microfluidic droplet sorting module 3 adopts an arc-shaped pipeline design made of PDMS material. The optimized structure enables the droplets to have a larger curvature radius at the sorting junction, reducing shear force and improving the stability and integrity of droplet sorting.

[0023] 2. The sorting electrode 3-2 of the microfluidic droplet sorting module 3 is in the shape of a pointed triangle, which can concentrate the electric field at the tip area of ​​the sorting electrode 3-2 and improve the local focusing effect of the electric field strength, thereby enhancing the accuracy of droplet sorting and making the electric field control precise.

[0024] 3. The FPGA signal processing module 5 includes functions such as ADC data acquisition, main control signal processing, and DAC pulse conversion, which can realize at least four-way multi-channel fluorescent droplet sorting, and improve the accuracy and stability of signal detection through real-time processing of fluorescent signals and baseline drift correction.

[0025] 4. Use Gigabit Ethernet communication module to realize high-speed data interaction between the host computer and the slave computer, ensure real-time visualization of droplet signals and fluorescence signals, and improve the flexibility of sorting parameter adjustment.

[0026] 5. Combining the inverted microscope 1, the XY precision moving platform 2 and the z-axis moving platform 6, not only can the precise sorting of droplets be achieved, but also the state of the droplets after sorting can be observed in real time through the microscope 1, and the parameters can be set through the human-computer interaction interface 5-5, and the fluorescent droplet sorting module 4 can be adjusted in real time to achieve closed-loop control of droplet manipulation, which is also convenient for subsequent analysis.

[0027] In summary, the present invention has been optimized in terms of microfluidic channel design, electric field control, signal processing and data transmission, which significantly improves the accuracy, stability and real-time performance of droplet sorting, and is suitable for high-throughput single-cell sorting experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0029] Figure 2 It is a side view of the present invention.

[0030] Figure 3 It is a structural schematic diagram of the microfluidic droplet sorting module 3.

[0031] Figure 4 This is a logic diagram of the FPGA droplet sorting module 5.

[0032] Figure 5 It is the upper computer software interface. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the instrument more clearly understood, the instrument is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0034] Reference Figure 1 , Figure 2, a droplet sorter based on fluorescence detection, includes an inverted microscope 1 for observing the generated droplet conditions, providing an observation source for setting the human-computer interaction parameters in the FPGA signal processing module 5. The inverted microscope 1 is at the bottom as the base of the whole instrument. An XY precise moving platform 2 is fixed in the side wall groove of the microscope 1. A simple support frame 7 is arranged beside the microscope 1, and a z-axis moving platform 6 is fixed on the simple support frame 7. The XY precise moving platform 2 and the z-axis moving platform 6 are used for the initial position calibration of the microfluidic sorting module 3. A fluorescence path 4-1 is installed on the z-axis moving platform 6. The fluorescence path 4-1 is a transparent pipeline in the light source irradiation direction. A microfluidic droplet sorting module 3 is fixed at the tip of the fluorescence path 4-1. A fluorescence detection module 4 is arranged on the side wall of the fluorescence path. Both the fluorescence detection module 4 and the microfluidic droplet sorting module 3 are connected to the signal terminals of the FPGA signal processing module 5 through network cables. After irradiating the sample, the generated fluorescence signal is converted and sent to the FPGA signal processing module 5. The FPGA signal processing module 5 realizes the signal transmission and processing, and controls the droplet sorting of the microfluidic droplet sorting module 3. A high-speed CCD camera 4-5 is installed at the end of the fluorescence path. The whole sorting process is monitored in real time by the high-speed CCD camera 4-5.

[0035] Refer to Figure 3 , the microfluidic droplet sorting module 3 is made of polydimethylsiloxane (PDMS), and its surface is a microfluidic channel. The channel at the sorting junction near the sorting electrode 3-2 is arc-shaped. The two ends of the arc shape are respectively connected to the inlet pipe 3-1 and the outlet pipe 3-3. This design is beneficial for the droplet to have a larger curvature radius at the sorting junction, and can reduce the shear force when the droplet enters the branch. The sorting electrode 3-2 is in a sharp triangular shape, that is, a "▲" shape, at the arc-shaped channel, so that the electric field is more concentrated in the electrode tip area. It helps to achieve more precise droplet manipulation. The sorting electrode 3-2 is connected to a high-voltage amplifier 3-4. The high-voltage amplifier 3-4 is connected to the FPGA signal processing module 5 through a DAC pulse signal conversion module 5-1.

[0036] The fluorescence detection module 4 includes a photomultiplier tube (PMT) 4-3 and an optical fiber 4-4 fixed on the side wall of the fluorescence path. The fluorescence molecules excited after the excitation light source 4-2 irradiates the sample generate fluorescence signals, which are transmitted through the optical fiber 4-4 and enter the photomultiplier tube 4-3. The photomultiplier tube 4-3 converts the optical signal into an electrical signal and transmits it to the FPGA signal processing module 5.

[0037] Refer to Figure 4, the FPGA signal processing module 5 includes a host computer part and a slave computer part. The slave computer includes an ADC data acquisition module 5-2, a main control module 5-3, and an Ethernet communication module 5-4. The signal terminal of the ADC data acquisition module 5-2 is connected to the photomultiplier tube 4-3, and converts the received analog signal into a digital signal that the main control module 5-3 can process. The collected fluorescence signal is buffered by the ADC data acquisition module (FIFO) 5-2 and called by the main control module 5-3. The Ethernet communication module 5-4 transmits the signal to the Ethernet communication interface 5-6 of the host computer. The host computer part is implemented on the PC side, and the parameters are set and visualized in the visualization module and parameter setting module of the human-computer interaction interface 5-5 for the signal transmitted in through the Ethernet communication interface 5-6.

[0038] The main control module 5-3 realizes the real-time detection of the collected signal and the control of the sorting pulse. The collected fluorescence signal is first denoised by mean filtering and corrected for baseline drift. Then the main control module 5-3 detects the intensity and duration of the processed signal to judge whether a droplet has passed through the microfluidic channel and whether the passed droplet is a target single-cell droplet. Then the main control module 5-3 issues a pulse control signal according to the detection result at the current moment. If a target single-cell droplet is detected passing through, the main control module 5-3 issues a pulse signal, and the DAC pulse signal conversion module 5-1 converts the digital signal into an analog signal and inputs it to the power amplifier 3-4. Then the power amplifier 3-4 amplifies the sorting pulse signal and transmits it to the sorting electrode 3-2 in the microfluidic droplet sorting module.

[0039] In the FPGA signal processing module 5, the Ethernet communication module 5-4 is used for communication between the slave computer and the host computer. The bidirectional transmission of data between the slave computer and the host computer is completed through Gigabit Ethernet. The slave computer transmits the processed fluorescence signal, signal duration and intensity, detection results, etc. to the host computer. The host computer transmits the signal duration threshold, signal intensity threshold, etc. to the slave computer.

[0040] In the host computer part of the FPGA signal processing module 5, the human-computer interaction interface 5-5 includes a visualization module and a parameter setting module. The parameter setting module is responsible for setting the gains of four PMTs, the selection of four channels, the droplet signal intensity threshold, the target single-cell droplet signal intensity threshold and duration threshold, the high and low levels of the sorting pulse, the duration of the sorting pulse, and the delay time of the sorting pulse, enabling the slave computer to flexibly process the sorting control of single-cell droplets in different situations. The data visualization module is used to receive data such as the fluorescence signal, droplet signal duration, and maximum droplet signal intensity processed by the slave computer. Then the signals received from the slave computer are refreshed regularly on the host computer, enabling users to set accurate sorting parameters according to the detection signals.

[0041] The working principle of the present invention is specifically as follows:

[0042] When the present invention starts to work, the XY precision movement platform 2 and the Z-axis movement platform 6 perform the initial position correction of the microfluidic sorting module. In order to enable the sorter to provide specific droplets as required, the contents thereof must be detectable by fluorescence. Droplets or microspheres with fluorescent markers are loaded into the inlet pipe 3-1 of the microfluidic droplet sorting module 3. Optical fibers 4-4 and detectors 4-1 are integrated on both sides of the channel. When the droplets flow through these areas, they emit fluorescence pulses. This generates specific peaks in the subsequent FPGA time series data, representing individual droplets excited by specific wavelengths;

[0043] Specifically, the fiber optic detector 4-1 is connected to the photomultiplier tube 4-3. The photomultiplier tube detects the fluorescence signal of the droplet and converts it into an electrical signal, which is converted into a digital signal via the ADC data acquisition module 5-2; preferably, the ADC data acquisition module uses AD7606, which has 16 bits, 8 channels, and a sampling rate of up to 200 kHz. The main control module 5-3 is connected to the ADC data acquisition module 5-2 to realize the filtering of the collected signal and the correction of the baseline drift. Specifically, the collected signal is denoised by mean filtering; the minimum value sequence is generated by calculating the minimum values within multiple windows, and the average value is calculated as the signal baseline. The filtered signal is subtracted from the baseline value to alleviate the baseline drift. Further, the minimum value sequence is maintained by a sliding window and the signal baseline is updated. Preferably, the main control module 5-3 uses the Artix-7 series XC7A100T-2-2FGG484I-2 control chip;

[0044] The main control module 5-3 further detects the signal after filtering and baseline correction to realize the detection of the droplet signal intensity, the detection of the target droplet signal intensity, the detection of the target droplet signal duration, and the control of the sorting pulse signal. Specifically, the detected signal is compared with the set droplet signal intensity threshold. If it is greater than the threshold, it is considered that a droplet is detected in the current cycle. If the detected signal in the current cycle is less than the threshold and the detected signal in the previous cycle is greater than the threshold, it is considered that the droplet has passed through the detection device; further, the main control module 5-3 stores and updates the maximum signal intensity and the signal duration during the detection of the droplet, and compares them with the set target droplet signal intensity threshold and the target droplet signal duration threshold after the droplet passes through the detection device. If both fall within the target threshold range, it is considered that the detected droplet is the target droplet, and a pulse sorting control signal is issued.

[0045] Further, after the main control module 5-3 issues a pulse sorting control signal, sorting pulses are generated according to the maximum voltage, minimum voltage, duration, signal frequency, delay time, etc. of the set pulse signal, and the digital signal is converted into an analog signal through the DAC pulse signal conversion module 5-1; further, the DAC pulse signal conversion module 5-1 is connected to the power amplifier 3-3, and after the signal is amplified, the dielectrophoretic force is generated through the driving sorting electrode 3-2 to control the offset of the target droplet in the microchannel. Preferably, the DAC pulse signal conversion module uses AD5676, which has 16 bits and 8 channels, and the typical settling time is 8 microseconds.

[0046] The communication between the lower computer and the upper computer is carried out through the Ethernet communication module 5-4. The ARP protocol and UDP protocol are implemented in the lower computer, which can capture the host address of the upper computer and send the filtered signal, the maximum value of the droplet signal intensity, the droplet signal duration, and the detection result to the upper computer.

[0047] The designed upper computer system is implemented based on Pyside, and the interface is as Figure 5 shown. The Ethernet communication between the upper computer system and the lower computer is implemented based on the socket library in Python. In the upper computer, the UDP packet from the lower computer is first parsed, and the detection signal waveform diagrams of four channels, the heat map of the droplet signal intensity, and the scatter diagram of the droplet signal duration are displayed.

[0048] Since the XY precision moving platform is installed above the objective lens of the inverted microscope, after the sorted droplets are spotted on the XY moving platform through the dispensing device, the generated droplet condition is observed through the microscope 1, and the parameters are set through the human-machine interaction interface 5-5, manually setting the droplet signal intensity, the PMT gain values of four channels, the four-channel signal selection, the target droplet intensity threshold, the target droplet duration threshold, the maximum voltage, minimum voltage, duration, pulse frequency, and delay time of the sorting pulse, and sending them to the lower computer through the Ethernet communication interface 5-6. Dynamically adjust the sorting process of the droplets to achieve the closed-loop control of the fluorescence droplet sorting.

[0049] Another function of the microscope 1 is for subsequent analysis. After the droplets are sorted, they will be deposited on the XY high-precision moving platform 2 by methods such as inkjet printing and EHD (electrohydrodynamic) printing, and the deposited droplet array is observed through the inverted microscope 1 placed under the platform.

Claims

1. A droplet sorter based on fluorescence detection, characterized in that: include: A microscope (1), which is inverted and located at the bottom as the base of the entire instrument, is used to observe the state of the generated droplets; Providing an observation source for setting the human-computer interaction parameters in the FPGA signal processing module (5); An XY precision moving platform (2) is fixed in a groove on the side wall of the microscope (1) and is used for initial position correction of the microfluidic sorting module (3); A z-axis moving platform (6), arranged next to the microscope (1), for calibrating the initial position of the microfluidic sorting module (3); The fluorescent passage (4-1) is a transparent pipeline installed on the z-axis moving platform (6) in the irradiation direction of the light source, and a fluorescent detection module (4) is installed on its side wall; A microfluidic droplet sorting module (3) is fixed at the tip of the fluorescent channel (4-1); the surface is designed as a microchannel to achieve droplet sorting; A fluorescence detection module (4) generates a fluorescence signal after irradiating the droplet and then converts the generated fluorescence signal and sends it to an FPGA signal processing module (5); The FPGA signal processing module (5) realizes signal transmission and processing, and controls the droplet sorting of the microfluidic droplet sorting module (3).

2. The droplet sorting instrument based on fluorescence detection according to claim 1, characterized in that: The microfluidic droplet sorting module (3) is made of polydimethylsiloxane (PDMS) and has a microfluidic channel on its surface. The channel at the sorting junction near the sorting electrode (3-2) is in an arc shape, and the two ends of the arc are respectively connected to the inlet pipe (3-1) and the outlet pipe (3-3). The sorting electrode (3-2) is in a pointed triangle shape at the arc-shaped channel. The sorting electrode (3-2) is connected to a high-voltage amplifier (3-4); the high-voltage amplifier (3-4) is connected to an FPGA signal processing module (5) via a DAC pulse signal conversion module (5-1).

3. The droplet sorting instrument based on fluorescence detection according to claim 1, characterized in that: The fluorescence detection module (4) comprises a photomultiplier tube (4-3) and an optical fiber (4-4) fixed on the side wall of the fluorescence path. After the excitation light source (4-2) irradiates the droplet, the excited fluorescent molecules generate a fluorescence signal which is transmitted through the optical fiber (4-4) and enters the photomultiplier tube (4-3). The photomultiplier tube (4-3) converts the optical signal into an electronic signal which is transmitted to the FPGA signal processing module (5).

4. The droplet sorting instrument based on fluorescence detection according to claim 1, characterized in that: The FPGA signal processing module (5) comprises a host computer and a slave computer, wherein the slave computer comprises an ADC data acquisition module (5-2), a main control module (5-3) and an Ethernet communication module 5-4; the signal end of the ADC data acquisition module (5-2) is connected to the photomultiplier tube (4-3) to convert the received analog signal into a digital signal that can be processed by the main control module (5-3); the collected fluorescence signal is buffered by the ADC data acquisition module (5-2) and called by the main control module (5-3); the Ethernet communication module (5-4) transmits the signal to the Ethernet communication interface (5-6) of the host computer, the host computer part is implemented on the PC end, and the signal transmitted from the Ethernet communication interface (5-6) is parameterized and visualized in the visualization module and parameter setting module of the human-computer interaction interface (5-5).

5. The droplet sorting instrument based on fluorescence detection according to claim 4, characterized in that: The main control module (5-3) realizes real-time detection of the collected signal and control of the sorting pulse; the collected fluorescence signal is first denoised by mean filtering and baseline drift correction is performed; then the main control module (5-3) detects the intensity and duration of the processed signal to determine whether a droplet has passed through the microfluidic channel and whether the passing droplet is a target single-cell droplet; then the main control module (5-3) sends a pulse control signal according to the current detection result; if the target single-cell droplet is detected to have passed, the main control module (5-3) sends a pulse signal, and the DAC pulse signal conversion module (5-1) converts the digital signal into an analog signal and inputs it into a power amplifier (3-4); then the power amplifier (3-4) amplifies the sorting pulse signal and transmits it to the sorting electrode (3-2) in the microfluidic droplet sorting module.

6. The droplet sorting instrument based on fluorescence detection according to claim 4, characterized in that: In the upper computer part of the FPGA signal processing module (5), the human-computer interaction interface (5-5) includes a visualization module and a parameter setting module. The parameter setting module is responsible for realizing the setting of four-way PMT gain, four-way channel selection, droplet signal intensity threshold, target single-cell droplet signal intensity threshold and duration threshold, sorting pulse high and low levels, sorting pulse duration, and sorting pulse delay time; enabling the lower computer to process single-cell droplet sorting control under different conditions; the data visualization module is used to receive the fluorescence signal, droplet signal duration, and droplet maximum signal intensity data processed by the lower computer; and then the upper computer periodically refreshes the received lower computer signal so that the user can realize accurate sorting parameter setting according to the detection signal.

7. The droplet sorting instrument based on fluorescence detection according to claim 1, characterized in that: A high-speed CCD camera (4-5) is installed at the end of the fluorescence channel to monitor the entire sorting process in real time.

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