Mass spectrometry apparatus and method for single cells

Abstract

The application provides a single cell mass spectrum detection device and method, and relates to the technical field of single cell mass spectrum detection. The device comprises a sealed cavity, a sample injector, a pulsed laser, a nanoliter electrospray mechanism, an electrode assembly and a mass spectrum sample inlet; opposite sides of the sealed cavity are respectively provided with a sample inlet and a discharge outlet; the sample injector is inserted into the sealed cavity through the sample inlet to focus single cell particles into a bundle; the pulsed laser is used for laser dissociation of the single cell to form cell fragments and metabolic products; the nanoliter electrospray mechanism is used for ionization of the cell fragments and the metabolic products to form sample ions; the electrode assembly is arranged in the sealed cavity, and the electrode assembly is used for dragging the sample ions into the mass spectrum sample inlet; the mass spectrum sample inlet is communicated with the sealed cavity. The application can effectively realize analysis of single cell cytoplasm or in-vivo metabolic products through pre-ionization and secondary electrospray ionization technology, and has the advantages of rapidness, high throughput, multi-component analysis and the like.

Description

Technical Field

[0001] This invention relates to the field of single-cell mass spectrometry detection technology, and more specifically, to a single-cell mass spectrometry detection device and method. Background Technology

[0002] Improving single-cell research capabilities can greatly promote the development of clinical medicine and basic life science research. However, for single-cell proteomics and metabolomics research, the extremely low concentration of analytes means that conventional analytical methods have limitations when applied to single-cell analysis, such as insufficient sensitivity and difficulty in multi-component analysis.

[0003] In recent years, mass spectrometry, as a highly sensitive detection technique, has been widely used in single-cell metabolomics and proteomics analysis. The most common application is the combination of flow cytometry and inductively coupled plasma mass spectrometry (ICP-MS), which uses metal probes to label single-cell samples. However, the difficulty of labeling multiple components with metal probes hinders high-throughput, multi-channel rapid detection. To achieve simultaneous detection of multiple components within single cells, open ion sources based on electrospray ionization (ESI) have been developed. Electrospray ionization is a "soft" ionization technique that directly obtains molecular ion peaks from the sample, aiding in spectral analysis. Currently, single-cell electrospray mass spectrometry analysis methods mainly fall into two categories. The first involves pretreatment, using extractants to extract intracellular substances before electrospray analysis; the second involves no pretreatment, directly using physical methods (such as probes) to extract cytoplasm before electrospray analysis. Both methods limit the high-throughput analysis capabilities of single-cell electrospray mass spectrometry.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a mass spectrometry detection device and method for single cells.

[0006] This invention is implemented as follows:

[0007] In a first aspect, the present invention provides a mass spectrometry detection device for a single cell, comprising a sealed cavity, a sample injector, a pulsed laser, a nanoliter electrospray mechanism, an electrode assembly, and a mass spectrometry inlet;

[0008] The sealed cavity has an inlet and an outlet on opposite sides for single-cell airflow to enter and exit.

[0009] The sampler is used to focus single-cell particles into a bundle, and the sampler is inserted into the sealed cavity through the sample inlet;

[0010] The pulsed laser is used to generate pulsed laser light to laser-dissociate single cells into cell fragments and metabolic products.

[0011] The nano-electrospray mechanism is used to ionize the cell debris and metabolites to form sample ions;

[0012] The electrode assembly is disposed in the sealed cavity, and the electrode assembly is used to generate a pulsed electric field to draw the sample ions into the mass spectrometer inlet;

[0013] The mass spectrometer inlet is connected to the sealed cavity.

[0014] In an optional embodiment, the nano-electrospray mechanism includes a reagent bottle, a high-pressure gas tube, a high-pressure electrode, and a capillary tube. The high-pressure gas tube, the high-pressure electrode, and the capillary tube are all inserted into the reagent bottle, which contains an aqueous formic acid solution. The capillary tube is inserted into the sealed cavity.

[0015] In an optional embodiment, the volume percentage concentration of the formic acid aqueous solution is 0.1-0.2%, nitrogen gas with a pressure of 0.11-0.15 MPa is introduced into the high-pressure gas tube, and a voltage of 3-5 kV is applied to the high-pressure electrode.

[0016] In an optional embodiment, the mass spectrometry detection device for a single cell further includes a continuous laser and a fluorescence detector, the continuous laser and the fluorescence detector being located between the sampler and the pulsed laser;

[0017] The continuous laser is used to excite fluorescently labeled single cells, causing the single cells to produce specific biofluorescence;

[0018] The fluorescence detector is used to detect the biological fluorescence, and after detecting the fluorescence pulse signal, it sends a signal to the pulsed laser.

[0019] In an optional embodiment, the spacing between the continuous laser and the pulsed laser is 0.5-1.5 mm;

[0020] In an optional embodiment, the fluorescence detector includes a focusing lens, an optical fiber, a filter, and a photomultiplier tube. The focusing lens is perpendicularly positioned in the direction of the continuous laser emitted by the continuous laser. The focusing lens collects fluorescence and scattered light. The optical fiber guides the collected fluorescence and scattered light into the filter. The filter removes the scattered light. The fluorescence signal enters the photomultiplier tube and is converted into a fluorescence pulse signal, which is then sent to the pulsed laser.

[0021] In an optional embodiment, the sampler is a nozzle or an aerodynamic lens.

[0022] Secondly, the present invention provides a method for mass spectrometry detection of a single cell, comprising using a single-cell mass spectrometry detection device as described in the foregoing embodiments; the method includes the following steps:

[0023] A single gaseous suspended cell is focused through the injector and introduced into the sealed cavity; the focused single cell moves downward along the central axis of the injector.

[0024] The moving single cell is dissociated by the pulsed laser generated by the pulsed laser to form cell debris and metabolic products;

[0025] The cell debris and metabolites formed are ionized by the electrospray ejected by the nano-electrospray mechanism to form sample ions;

[0026] The formed sample ions are drawn into the mass spectrometer inlet by the electrode assembly.

[0027] In an optional embodiment, the gaseous individual suspended cells are fluorescently labeled;

[0028] Before being dissociated by the pulsed laser, the moving single cell also includes being excited by a continuous laser to produce biofluorescence by fluorescently labeled single cells.

[0029] The biofluorescence was detected using a fluorescence detector;

[0030] When the fluorescence detector detects the biofluorescence, it sends a signal to the pulsed laser, which then generates a pulsed laser to dissociate the single cell.

[0031] In an optional embodiment, the electrode assembly includes a first electrode and a second electrode disposed opposite to each other, the second electrode being disposed at the mass spectrometer inlet; the electrode assembly drawing the sample ions into the mass spectrometer inlet includes: adjusting the first electrode to a low level and the second electrode to a high level before the pulsed laser generates pulsed laser light; and adjusting the first electrode to a high level and the second electrode to a low level after the pulsed laser generates pulsed laser light.

[0032] The present invention has the following beneficial effects: The single-cell mass spectrometry detection device and method provided in this application adopts aerodynamic technology for high-throughput sample introduction, followed by a pulsed laser and a nano-electrospray mechanism. The pulsed laser pre-ionizes the single cell to form cell debris and metabolites. Then, the nano-electrospray mechanism is used for secondary electrospray ionization technology to process the cell debris and metabolites into sample ions, which can effectively realize the analysis of single-cell cytoplasm or in vivo metabolites, and has the advantages of being fast, high-throughput, and multi-component analysis. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of the mass spectrometry detection device for a single cell provided in the first embodiment of this application;

[0035] Figure 2 A schematic diagram of the structure of the mass spectrometry detection device for a single cell provided in the first embodiment of this application, showing the combination of a continuous laser and a fluorescence detector.

[0036] Figure 3 This is a schematic diagram of the nano-electrospray mechanism of the mass spectrometry detection device for a single cell provided in the first embodiment of this application;

[0037] Figure 4 The timing diagram shows the operation of the fluorescence detector, pulsed laser, first electrode, and second electrode in the mass spectrometry detection device for a single cell provided in the first embodiment of this application when they are linked together.

[0038] Icons: 100-Mass spectrometry detection device for single cells; 110-Sealed cavity; 111-Inlet; 120-Injector; 130-Continuous laser; 140-Fluorescence detector; 141-Focusing lens; 142-Fiber optic cable; 143-Filter; 144-Photomultiplier tube; 150-Pulsed laser; 160-Nano-electrospray mechanism; 161-Reagent bottle; 162-High-pressure gas tube; 163-High-pressure electrode; 164-Capillary; 170-Electrode assembly; 171-First electrode; 172-Second electrode; 180-Mass spectrometer inlet. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0041] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0042] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0043] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0044] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0045] First Embodiment

[0046] Please see Figure 1 This embodiment provides a single-cell mass spectrometry detection device 100, which includes a sealed cavity 110, a sample injector 120, a continuous laser 130, a fluorescence detector 140, a pulsed laser 150, a nanoliter electrospray mechanism 160, an electrode assembly 170, and a mass spectrometry sample inlet 180.

[0047] The sealed cavity 110 is used to guide the entry and exit of single-cell gas flow. The sealed cavity 110 has an inlet 111 and an outlet (not shown in the figure) on opposite sides for the entry and exit of single-cell gas flow.

[0048] The sampler 120 is inserted into the sealed cavity 110 through the sample inlet 111, thereby spraying single-cell particles into the sealed cavity 110. The sampler 120 in this application can be a nozzle or an aerodynamic lens, and its function is to use aerodynamic methods to focus the single-cell particles into a beam for subsequent fluorescence analysis and laser dissociation.

[0049] The continuous laser 130 is used to excite fluorescently labeled single cells, causing them to produce specific biofluorescence. The continuous laser 130 in this application can be selected from various sources, including but not limited to lasers with wavelengths of 355 nm, 405 nm, and 633 nm. Specifically, the wavelength of the continuous laser emitted by the continuous laser 130 can be selected according to the fluorescent label. After the continuous laser 130 emits the laser, it can be focused into a spot of approximately 300 μm by the focusing lens 141. The focused spot is on the trajectory of the single cell after it passes through the sampler 120.

[0050] The fluorescence detector 140 is used to detect biological fluorescence and sends a signal to the pulsed laser 150 after detecting a fluorescence pulse signal. In this application, the fluorescence detector 140 can collect biological fluorescence and scattered light, and then remove the scattered light of the continuous laser through an optical filter (e.g., filter 143) to detect the excited fluorescence.

[0051] Specifically, please refer to Figure 2 The fluorescence detector 140 in this application includes a focusing lens 141, an optical fiber 142, a filter 143, and a photomultiplier tube 144. The focusing lens 141 is vertically positioned in the direction of the continuous laser emitted by the continuous laser 130. The focusing lens 141 collects fluorescence and scattered light. The probe of the optical fiber 142 guides the collected fluorescence and scattered light into the filter 143, which removes the scattered light. The fluorescence signal enters the photomultiplier tube 144 and is converted into a fluorescence pulse signal, which is then sent to the pulsed laser 150. The fluorescence detector 140 is configured to clearly determine when a single cell arrives at the pulsed laser, ensuring that the pulsed laser 150 can hit the single cell when it fires. In this application, after the fluorescence detector 140 detects the arrival of a single cell, it sends a fluorescence pulse signal to the pulsed laser for triggering. After receiving the fluorescence pulse signal, the pulsed laser then emits its own laser beam.

[0052] The pulsed laser 150 is used to generate pulsed laser light upon receiving a fluorescence pulse signal to laser-dissociate single cells into cell debris and metabolic products. The distance between the continuous laser 130 and the pulsed laser 150 is 0.5-1.5 mm. The pulsed laser 150 in this application is a high-energy pulsed laser with extremely high response speed. After the fluorescence detector 140 detects biofluorescence, it sends a signal to the pulsed laser 150. Upon receiving the signal, the pulsed laser 150 emits laser light within a few microseconds to laser-dissociate single cells into cell debris or other subcellular structures for rapid mass spectrometry structural analysis. Because the sealed cavity 110 in this application is under atmospheric pressure, the amount of ions generated by the pulsed laser 150 under atmospheric pressure is relatively small, mainly used for ablation and dissociation of cells, causing cells to form cell debris, metabolic products, or other subcellular structures. Since the pulsed laser 150 excites a relatively small amount of ions, it avoids the pulsed laser 150 directly dissociating single cells into ions that are too small to be easily analyzed by subsequent mass spectrometry.

[0053] It is worth noting that while the pulsed laser generated by the pulsed laser 150 can also excite fluorescent markers, the fluorescence produced by the pulsed laser 150 differs from that produced by the continuous laser 130. Therefore, in this application, by selecting an appropriate aperture for the fiber 142, only the spot of the fluorescent marker excited by the continuous laser 130 can be detected by the fluorescence detector 140, while the spot of the fluorescent marker excited by the pulsed laser 150 will not be detected by the fluorescence detector 140. This effectively avoids secondary triggering of the fluorescence detector 140. This application does not limit the specific aperture of the fiber 142; it can be determined based on the selection of the fluorescent marker, the pulsed laser 150, and the continuous laser in the actual application.

[0054] The nano-electrospray mechanism 160 is used to ionize cell debris and metabolites to form sample ions. The nano-electrospray mechanism 160 provided in this application is a primary ion generation module that ionizes cell debris and metabolites to form sample ions for subsequent mass spectrometry analysis.

[0055] In this application, please refer to Figure 3The nano-electrospray mechanism 160 includes a reagent bottle 161, a high-pressure gas tube 162, a high-pressure electrode 163, and a capillary tube 164. All three components are inserted into the reagent bottle 161, which contains an aqueous formic acid solution. The capillary tube 164 is inserted into a sealed cavity 110. The formic acid solution has a volume percentage concentration of 0.1-0.2%. Nitrogen gas at a pressure of 0.11-0.15 MPa is introduced into the high-pressure gas tube 162. A voltage of 3-5 kV is applied to the high-pressure electrode 163. Under the influence of high voltage and high pressure, the formic acid solution forms an electrospray that exits through the capillary tube 164. This electrospray can ionize cell debris and metabolic products within the sealed cavity 110 to form sample ions.

[0056] Nano-liter electrospray ionization (SSI) is a highly efficient ionization technique developed based on ESI, offering advantages such as small sample requirements, high ionization efficiency, and the ability to analyze multiple samples simultaneously. Secondary electrospray ionization (SESI), formed through nano-liter SSI, enables in-situ sample analysis and has been applied in VOCs detection and aerosol extraction analysis. However, SESI sources are rarely used directly for single-cell analysis, primarily due to the limitations of cell structure, making it difficult to directly extract intracellular substances via secondary electrospray ionization. In this application, a pulsed laser 150 is used to laser-dissociate single cells into cell debris and metabolites. Subsequently, a nano-liter electrospray mechanism 160 ionizes these cell debris and metabolites to form sample ions. This allows the nano-liter electrospray mechanism 160 to effectively obtain intracellular substances, and the sample ion size is well-controlled, facilitating subsequent multi-component mass spectrometry analysis.

[0057] The electrode assembly 170 is disposed inside the sealed cavity 110. The electrode assembly 170 is used to generate a pulsed electric field to draw sample ions into the mass spectrometer inlet 180.

[0058] In this application, the electrode assembly 170 includes a first electrode 171 and a second electrode 172 disposed opposite to each other, with the second electrode 172 located at the mass spectrometer inlet 180. This application achieves directional ion movement by adjusting the output levels of the first electrode 171 and the second electrode 172. For details, please refer to... Figure 4 Ions move from high level to low level. When no ions are needed to enter the mass spectrometer inlet 180, the first electrode 171 is set to low level and the second electrode 172 is set to high level. At this time, the entry of ions into the mass spectrometer inlet 180 is obstructed. When ions are needed to enter the mass spectrometer inlet 180, the first electrode 171 is set to high level and the second electrode 172 is set to low level. By adjusting the levels of the first electrode 171 and the second electrode 172, ions are drawn into the mass spectrometer inlet 180 for mass spectrometry detection.

[0059] In this application, the mass spectrometer inlet 180 is connected to the sealed cavity 110, and the other end of the mass spectrometer inlet 180 is connected to the mass spectrometer. The mass spectrometer inlet 180 in this application is a universal mass spectrometer interface, used to introduce atmospheric pressure ions into the mass spectrometer in the vacuum system for analysis. The commonly used atmospheric pressure interface has an inlet flow rate of 1-2 L / min.

[0060] This application combines aerodynamic sample introduction technology, fluorescence detection, pulsed laser pre-dissociation, and secondary electrospray ionization to achieve high-throughput, multi-component, and high-sensitivity mass spectrometry detection of single cells. High-throughput single-cell sample introduction is achieved using aerodynamic lens sample introduction technology, followed by fluorescence detection to detect single-cell movement trajectories, then pulsed laser dissociation to achieve cell dissociation, and finally, high-efficiency secondary electrospray ionization technology to achieve multi-component, high-sensitivity detection of single cells.

[0061] This application employs a fluorescence detector 140 to track single cells, a pulsed laser 150 for pre-ionization, and then a nano-electrospray mechanism 160 for secondary electrospray ionization. This enables the analysis of single-cell cytoplasm or in vivo metabolites at a rapid pace. Compared to pretreatment or physical methods, it offers advantages such as speed, high throughput, and multi-component analysis.

[0062] Second Embodiment

[0063] This embodiment provides a mass spectrometry detection method for a single cell, which is performed using the single-cell mass spectrometry detection device 100 provided in the first embodiment. Specifically, the single-cell mass spectrometry detection method provided in this embodiment includes the following steps:

[0064] S1. A fluorescently labeled single-cell suspension is atomized to form gaseous single suspended cells. The gaseous single suspended cells are focused through the injector 120 and introduced into the sealed cavity 110. The focused single cells move downward along the central axis of the injector 120.

[0065] S2. A continuous laser 130 is used to excite fluorescently labeled single cells, causing the single cells to produce biofluorescence;

[0066] S3. A fluorescence detector 140 is used to detect biological fluorescence;

[0067] S4. When the fluorescence detector 140 detects biofluorescence, it sends a signal to the pulsed laser 150. The pulsed laser 150 generates pulsed laser to dissociate single cells, forming cell debris and metabolic products.

[0068] S5. The cell debris and metabolites formed are ionized by the electrospray spray from the nano-electrospray mechanism 160 to form sample ions.

[0069] S6. Before the pulsed laser 150 generates pulsed laser light, the first electrode 171 is adjusted to a low level and the second electrode 172 is adjusted to a high level; after the pulsed laser 150 generates pulsed laser light, the first electrode 171 is adjusted to a high level and the second electrode 172 is adjusted to a low level. The formed sample ions are drawn into the mass spectrometer inlet 180 by the electrode assembly 170.

[0070] The single-cell mass spectrometry detection method provided in this application employs aerodynamic technology for sample introduction, followed by the use of a continuous laser 130 and a fluorescence detector 140 to determine the trajectory of the single cell. When the fluorescence detector 140 detects biofluorescence, it sends a signal to a pulsed laser 150, which generates pulsed laser light to dissociate the single cell, forming cell debris and metabolic products. In this application, the pulsed laser 150 pre-ionizes the single cell, followed by secondary electrospray ionization using a nanoliter electrospray mechanism 160. This process allows cell debris and metabolic products to form sample ions, effectively enabling the analysis of single-cell cytoplasm or in vivo metabolic products, and offers advantages such as speed, high throughput, and multi-component analysis.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A mass spectrometry detection device for a single cell, characterized in that, It includes a sealed cavity, a sample injector, a pulsed laser, a nanoliter electrospray mechanism, an electrode assembly, and a mass spectrometer inlet; The sealed cavity has an inlet and an outlet on opposite sides for single-cell gas flow to enter and exit. The sample injector is a nozzle or aerodynamic lens, used to focus single-cell particles into a beam. The sample injector is inserted into the sealed cavity through the inlet. The pulsed laser generates pulsed laser light to laser-dissociate single cells into cell debris and metabolic products. The nano-electrospray mechanism includes a reagent bottle, a high-pressure gas tube, a high-pressure electrode, and a capillary. The high-pressure gas tube, the high-pressure electrode, and the capillary are all inserted into the reagent bottle, which contains an aqueous formic acid solution. The capillary is inserted into the sealed cavity. The nano-electrospray mechanism ionizes the cell debris and metabolic products to form sample ions. The electrode assembly is disposed in the sealed cavity and generates a pulsed electric field to draw the sample ions into the mass spectrometer inlet. The mass spectrometer inlet is connected to the sealed cavity.

2. The mass spectrometry detection device for a single cell according to claim 1, characterized in that, The formic acid aqueous solution has a volume percentage concentration of 0.1-0.2%, nitrogen gas with a pressure of 0.11-0.15 MPa is introduced into the high-pressure gas tube, and a voltage of 3-5 kV is applied to the high-pressure electrode.

3. The mass spectrometry detection device for a single cell according to claim 1, characterized in that, The mass spectrometry detection device for a single cell further includes a continuous laser and a fluorescence detector, wherein the continuous laser and the fluorescence detector are located between the sample injector and the pulsed laser; The continuous laser is used to excite fluorescently labeled single cells, causing the single cells to produce specific biofluorescence; The fluorescence detector is used to detect the biological fluorescence, and after detecting the fluorescence pulse signal, it sends a signal to the pulsed laser.

4. The mass spectrometry detection device for a single cell according to claim 3, characterized in that, The distance between the continuous laser and the pulsed laser is 0.5-1.5 mm.

5. The mass spectrometry detection device for a single cell according to claim 3, characterized in that, The fluorescence detector includes a focusing lens, an optical fiber, a filter, and a photomultiplier tube. The focusing lens is perpendicularly positioned in the direction of the continuous laser emitted by the continuous laser. The focusing lens collects fluorescence and scattered light. The optical fiber guides the collected fluorescence and scattered light into the filter. The filter removes the scattered light. The fluorescence signal enters the photomultiplier tube and is converted into a fluorescence pulse signal, which is then sent to the pulsed laser.

6. A mass spectrometry detection method for a single cell, characterized in that, It includes using the mass spectrometry detection device for a single cell as described in claim 1; it includes the following steps: A single gaseous suspended cell is focused through the injector and introduced into the sealed cavity; the focused single cell moves downward along the central axis of the injector. The moving single cell is dissociated by the pulsed laser generated by the pulsed laser to form cell debris and metabolic products; The cell debris and metabolites formed are ionized by the electrospray ejected by the nano-electrospray mechanism to form sample ions; The formed sample ions are drawn into the mass spectrometer inlet by the electrode assembly.

7. The mass spectrometry detection method for a single cell according to claim 6, characterized in that, The gaseous, single suspended cells are fluorescently labeled; Before being dissociated by the pulsed laser, the moving single cell also includes being excited by a continuous laser to produce biofluorescence by fluorescently labeled single cells. The biofluorescence was detected using a fluorescence detector; When the fluorescence detector detects the biofluorescence, it sends a signal to the pulsed laser, which then generates a pulsed laser to dissociate the single cell.

8. The mass spectrometry detection method for a single cell according to claim 6, characterized in that, The electrode assembly includes a first electrode and a second electrode disposed opposite to each other, with the second electrode disposed at the mass spectrometer inlet. The electrode assembly guides the sample ions into the mass spectrometer inlet by: adjusting the first electrode to a low level and the second electrode to a high level before the pulsed laser generates a pulsed laser; When the pulsed laser generates pulsed laser light, the first electrode is adjusted to a high level and the second electrode to a low level.

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