CN117030835A - Micro-droplet extraction sampling mass spectrum imaging device and method based on laser displacement feedback - Google Patents
Micro-droplet extraction sampling mass spectrum imaging device and method based on laser displacement feedback Download PDFInfo
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- 238000003384 imaging method Methods 0.000 title claims abstract description 87
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- 238000000605 extraction Methods 0.000 title claims abstract description 37
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- 238000004949 mass spectrometry Methods 0.000 claims abstract description 29
- 238000000520 microinjection Methods 0.000 claims abstract description 22
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
- G01N27/68—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode using electric discharge to ionise a gas
Abstract
The application relates to a micro-droplet extraction sampling mass spectrum imaging device and method based on laser displacement feedback, comprising the following steps: continuously feeding the solution into a front-stage capillary through a microinjection pump to form a flowing liquid bridge between the solution and a rear-stage capillary, generating an adjusting signal when the distance between the flowing liquid bridge and a tissue sample on an objective table does not meet a preset condition by utilizing a laser displacement sensing feedback module, adjusting the distance to be a target sampling distance through a three-dimensional electric displacement platform so as to extract and sample micro liquid drops of the tissue sample to obtain a sample to be analyzed, forming high-voltage electric spray between the rear-stage capillary and a mass spectrometer by utilizing a pneumatic auxiliary device, ionizing the sample to be analyzed, feeding the ionized sample into the mass spectrometer, and carrying out mass spectrometry on the ionized sample to be analyzed by utilizing the mass spectrometer to obtain an imaging result of the sample to be analyzed. Therefore, the problems that the relative distance between a sampling liquid bridge and the surface of a sample is difficult to control accurately, the electrospray stability is low, the imaging spatial resolution is low and the cost is high in the imaging process are solved.
Description
Technical Field
The application relates to the field of mass spectrum imaging, in particular to a micro-droplet extraction sampling mass spectrum imaging device and method based on laser displacement feedback.
Background
The spectrum imaging technology is a technology capable of simultaneously obtaining chemical component information and spatial distribution information of target biological tissues, and plays an important role in biological tissue research and analytical chemistry research. In-situ ionization mass spectrometry imaging technology has been developed rapidly in the last twenty years, and compared with the most commonly used MALDI mass spectrometry imaging technology, the method has the greatest advantage that the method almost does not need any pretreatment step of a sample, and can carry out mass spectrometry imaging scanning analysis on the sample in an atmospheric pressure environment.
In the related art, the in-situ ionization method mainly comprises DESI ((Desorption Electrospray Ionization) desorption electrospray ionization), and is widely applied because no sample pretreatment and better analysis sensitivity are needed, but because the DESI adopts a gas spray sampling analysis mode, high-resolution imaging analysis is difficult, and in general, the DESI mass spectrum imaging can only obtain 50-200 mu m imaging resolution.
However, in the conventional Nano-DESI imaging method, spraying is usually performed by using the pumping force of a mass spectrum vacuum system and the action of high pressure, and in a scene that mass spectrum such as discontinuous sample injection is difficult to provide stable pumping force, when bubbles appear in a capillary, the stability of an electrospray signal is directly affected, and even signal interruption is caused. Meanwhile, another main reason for the limitation of Nano-DESI technology is that the relative distance between the sampling liquid bridge and the surface of the sample is difficult to control accurately, which can lead to the liquid bridge separating from the surface of the sample in the scanning process or the front and rear capillaries colliding with the sample in the actual imaging process due to the inclination of the electric displacement table or the uneven surface of the sample.
Therefore, related technicians monitor the distance between a sample and the probe in real time in the imaging process by adopting a piezoelectric probe mode, and realize accurate control of the probe and the surface of the sample by feeding back and controlling an electric displacement table in the z direction according to distance information, thereby realizing micrometer-level feedback positioning accuracy so as to ensure the stability in the imaging scanning process, but the method has higher cost and complex device realization and needs to be solved urgently.
Disclosure of Invention
The application provides a micro-droplet extraction sampling mass spectrum imaging device and method based on laser displacement feedback, which are used for solving the problems that the relative distance between a sampling liquid bridge and the surface of a sample is difficult to accurately control, the electrospray stability is low, the imaging spatial resolution is low, the cost is high and the like in the imaging process.
An embodiment of a first aspect of the present application provides a micro-droplet extraction sampling mass spectrometry imaging device based on laser displacement feedback, including: a microinjection pump, a front stage capillary, a rear stage capillary, an objective table, a three-dimensional electric displacement platform, a pneumatic auxiliary device, a laser displacement sensing feedback module and a mass spectrometer, wherein,
the microinjection pump is used for continuously feeding the solution into the pre-stage capillary tube so that a flowing liquid bridge is formed between the pre-stage capillary tube and the post-stage capillary tube;
the laser displacement sensing feedback module is used for generating an adjusting signal when the distance between the flowing liquid bridge and the tissue sample on the objective table does not meet the preset condition;
the three-dimensional electric displacement platform is used for adjusting the distance to be a target sampling distance according to the adjusting signal so as to conduct micro-droplet extraction sampling on the tissue sample to obtain a sample to be analyzed;
the pneumatic auxiliary device is used for forming high-pressure electric spray between the rear-stage capillary and the mass spectrometer so as to ionize the sample to be analyzed and send the ionized sample to the mass spectrometer; and
the mass spectrometer is used for carrying out mass spectrometry on the ionized sample to be analyzed to obtain an imaging result of the sample to be analyzed.
Optionally, the pre-stage capillary and the post-stage capillary are placed in a V-shape.
Optionally, the laser displacement sensing feedback module includes:
the laser displacement sensor is used for collecting the distance between the flowing liquid bridge and the tissue sample on the objective table;
the conversion unit is used for converting the distance and then sending the converted distance to the judgment unit;
the judging unit is used for judging whether the converted distance meets the preset condition or not, and sending a control signal to the three-dimensional electric displacement platform when the converted distance does not meet the preset condition.
Optionally, the micro-droplet extraction sampling mass spectrum imaging device based on laser displacement feedback further includes:
and the pull tip assembly is used for carrying out pull tip on the pre-stage capillary and the post-stage capillary based on a preset pull tip strategy.
Optionally, the rear-stage capillary tube is connected with the pneumatic auxiliary device by a T-shaped three-way tube, the first end and the second end of the T-shaped three-way tube are connected with the rear-stage capillary tube, and the third end of the T-shaped three-way tube is connected with the pneumatic auxiliary device.
Optionally, both the first end and the second end are sealed with teflon tubing.
Optionally, the helium flow rate of the pneumatic assist device is determined by the pumping force of the mass spectrometer.
According to the micro-droplet extraction sampling mass spectrum imaging device based on laser displacement feedback, a micro-injection pump is used for continuously feeding a solution into a front-stage capillary tube, a flowing liquid bridge is formed between the micro-injection pump and a rear-stage capillary tube, an adjusting signal is generated when the distance between the flowing liquid bridge and a tissue sample on an objective table does not meet a preset condition by using a laser displacement sensing feedback module, the distance is adjusted to be a target sampling distance by using a three-dimensional electric displacement platform, micro-droplet extraction sampling is performed on the tissue sample, a sample to be analyzed is obtained, a high-voltage electric spray is formed between the rear-stage capillary tube and a mass spectrometer by using a pneumatic auxiliary device, the sample to be analyzed is ionized and then fed into the mass spectrometer, and mass spectrometry is performed on the ionized sample to be analyzed by using the mass spectrometer, so that an imaging result of the sample to be analyzed is obtained. Therefore, the problems that the relative distance between the sampling liquid bridge and the sample surface is difficult to control accurately, the electrospray stability is low, the imaging spatial resolution is low and the cost is high in the imaging process are solved, the micron-scale precision control and the electrospray stability of the relative distance between the sampling liquid bridge and the sample surface in the imaging process are realized by adding the laser displacement feedback module and the pneumatic auxiliary device, and the imaging spatial resolution is improved by carrying out the tip pulling treatment on the front capillary and the rear capillary.
An embodiment of a second aspect of the present application provides a method for micro-droplet extraction sampling mass spectrometry imaging based on laser displacement feedback, using a micro-droplet extraction sampling mass spectrometry imaging device based on laser displacement feedback as described in the embodiment of the first aspect, the method comprising the steps of:
continuously feeding a solution into the pre-stage capillary by the microinjection pump, so that a flowing liquid bridge is formed between the pre-stage capillary and the post-stage capillary;
generating an adjusting signal when the distance between the flowing liquid bridge and the tissue sample on the objective table does not meet a preset condition by utilizing the laser displacement sensing feedback module;
adjusting the distance to be a target sampling distance through the three-dimensional electric displacement platform according to the adjusting signal so as to extract and sample micro liquid drops of the tissue sample to obtain a sample to be analyzed;
forming high-pressure electric spray between the rear-stage capillary and the mass spectrometer by utilizing the pneumatic auxiliary device so as to ionize the sample to be analyzed and send the ionized sample to the mass spectrometer; and
and carrying out mass spectrometry on the ionized sample to be analyzed by the mass spectrometer to obtain an imaging result of the sample to be analyzed.
Optionally, the micro-droplet extraction sampling mass spectrometry imaging method based on laser displacement feedback further includes:
and carrying out drawing on the front-stage capillary and the rear-stage capillary based on a preset drawing strategy.
According to the micro-droplet extraction sampling mass spectrum imaging method based on laser displacement feedback, a micro-injection pump is used for continuously feeding a solution into a front-stage capillary tube, a flowing liquid bridge is formed between the micro-injection pump and a rear-stage capillary tube, an adjusting signal is generated when the distance between the flowing liquid bridge and a tissue sample on an objective table does not meet a preset condition by using a laser displacement sensing feedback module, the distance is adjusted to be a target sampling distance by using a three-dimensional electric displacement platform, micro-droplet extraction sampling is performed on the tissue sample, a sample to be analyzed is obtained, a high-voltage electric spray is formed between the rear-stage capillary tube and a mass spectrometer by using a pneumatic auxiliary device, the sample to be analyzed is ionized and then fed into the mass spectrometer, and mass spectrometry is performed on the ionized sample to be analyzed by using the mass spectrometer, so that an imaging result of the sample to be analyzed is obtained. Therefore, the problems that the relative distance between the sampling liquid bridge and the sample surface is difficult to control accurately, the electrospray stability is low, the imaging spatial resolution is low and the cost is high in the imaging process are solved, the micron-scale precision control and the electrospray stability of the relative distance between the sampling liquid bridge and the sample surface in the imaging process are realized by adding the laser displacement feedback module and the pneumatic auxiliary device, and the imaging spatial resolution is improved by carrying out the tip pulling treatment on the front capillary and the rear capillary.
Additional aspects and advantages of the application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the application.
Drawings
The foregoing and/or additional aspects and advantages of the application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:
fig. 1 is a schematic diagram of a micro-droplet extraction sampling mass spectrometry imaging device based on laser displacement feedback according to an embodiment of the present application;
FIG. 2 is a schematic diagram of a laser displacement feedback module according to one embodiment of the present application;
FIG. 3 is a schematic diagram of a front-to-back capillary pull tip style in accordance with one embodiment of the present application;
FIG. 4 is a schematic diagram of a distance feedback test result of a laser displacement feedback system according to an embodiment of the present application;
FIG. 5 is a schematic view of a scan path for imaging a tissue sample according to one embodiment of the application;
FIG. 6 is a schematic representation of the results of imaging a mouse brain Nano-DESI using the present application, according to one embodiment of the present application;
fig. 7 is a flow chart of a micro-droplet extraction sampling mass spectrometry imaging method based on laser displacement feedback according to an embodiment of the application.
Detailed Description
Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present application and should not be construed as limiting the application.
The application provides a micro-droplet extraction sampling mass spectrum imaging device based on laser displacement feedback, which is characterized in that a micro-injection pump is used for continuously feeding a solution into a front-stage capillary tube to form a flowing liquid bridge with a rear-stage capillary tube, a laser displacement sensing feedback module is used for generating an adjusting signal when the distance between the flowing liquid bridge and a tissue sample on a stage does not meet preset conditions, the distance is adjusted to be a target sampling distance through a three-dimensional electric displacement platform, so that micro-droplet extraction sampling is carried out on the tissue sample to obtain a sample to be analyzed, a pneumatic auxiliary device is used for forming high-voltage spray between the rear-stage capillary tube and the mass spectrometer, the sample to be analyzed is ionized and then fed into the mass spectrometer, and the ionized sample to be analyzed is analyzed through the mass spectrometer to obtain an imaging result of the sample to be analyzed. Therefore, the problems that the relative distance between the sampling liquid bridge and the sample surface is difficult to control accurately, the electrospray stability is low, the imaging spatial resolution is low and the cost is high in the imaging process are solved, the micron-scale precision control and the electrospray stability of the relative distance between the sampling liquid bridge and the sample surface in the imaging process are realized by adding the laser displacement feedback module and the pneumatic auxiliary device, and the imaging spatial resolution is improved by carrying out the tip pulling treatment on the front capillary and the rear capillary. .
Specifically, fig. 1 is a schematic block diagram of a micro-droplet extraction sampling mass spectrometry imaging device based on laser displacement feedback according to an embodiment of the present application.
As shown in fig. 1, the micro-droplet extraction sampling mass spectrometry imaging device 10 based on laser displacement feedback comprises: microinjection pump 100, pre-stage capillary 200, post-stage capillary 300, stage 400, three-dimensional motorized displacement stage 500, pneumatic assist device 600, laser displacement sensing feedback module 700, and mass spectrometer 800.
The microinjection pump 100 is used for continuously feeding the solution into the pre-stage capillary 200, so that a flowing liquid bridge is formed between the pre-stage capillary 200 and the post-stage capillary 300; the laser displacement sensing feedback module 700 is configured to generate an adjustment signal when the distance between the flowing liquid bridge and the tissue sample on the stage 400 does not satisfy a preset condition; the three-dimensional electric displacement platform 500 is used for adjusting the distance to be a target sampling distance according to the adjusting signal so as to conduct micro-droplet extraction sampling on the tissue sample to obtain a sample to be analyzed; the pneumatic auxiliary device 600 is used for forming high-pressure electric spray between the post-stage capillary 300 and the mass spectrometer 800 so as to ionize a sample to be analyzed and send the ionized sample into the mass spectrometer 800; the mass spectrometer 800 is used for performing mass spectrometry on the ionized sample to be analyzed to obtain an imaging result of the sample to be analyzed.
Optionally, the laser displacement sensing feedback module 700 includes: the laser displacement sensor is used for collecting the distance between the flowing liquid bridge and the tissue sample on the objective table; the conversion unit is used for converting the distance and then sending the converted distance to the judgment unit; the judging unit is configured to judge whether the converted distance meets a preset condition, and send a control signal to the three-dimensional electric displacement platform 500 when the converted distance does not meet the preset condition.
The preset conditions may be related conditions set by those skilled in the art according to the sampling requirements, and are not specifically limited herein.
Specifically, the laser displacement sensing feedback module 700 of the embodiment of the present application is composed of a laser displacement sensor, a conversion unit and a judgment unit, where the conversion unit may be a high-precision AD conversion chip, and the judgment unit may be a development board.
Further, in the feedback process of the laser displacement sensor, the laser displacement sensor samples the collected position information of the flowing liquid bridge and the tissue sample on the objective table 400 through the high-precision AD conversion chip and then transmits the sampled position information to the development board; and secondly, the development board compares the position information of the converted flowing liquid bridge and the tissue sample on the objective table 400 with preset position threshold information, judges whether the converted position information meets preset conditions, and sends a control signal to the three-dimensional electric displacement platform 500 when the converted position information does not meet the preset conditions, namely when the fed back converted distance value exceeds the preset threshold range, the development board sends the control signal to the three-dimensional electric displacement platform 500 in the z direction, and the feedback control of the distance relative distance between the flowing liquid bridge and the tissue sample on the objective table 400 is realized, so that the real-time accurate control of the sampling distance between the flowing liquid bridge and the tissue sample on the objective table 400 is realized.
Specifically, in the embodiment of the present application, as shown in fig. 2, the laser displacement sensor 81 samples the collected position information of the flowing liquid bridge and the tissue sample on the stage through the 16-bit ADC 82, and then sends the sampled position information to the Arduino development board 83, the Arduino development board 83 compares the collected position information of the flowing liquid bridge and the tissue sample on the stage with the preset position threshold value information, when the feedback position information value exceeds the preset threshold value range, the Arduino development board 83 sends a control signal to the three-dimensional electric displacement platform 500 in the z direction, and after the sample is initially tested and adjusted, the three-dimensional electric displacement platform 500 is controlled to scan the sample in the xy direction, so as to realize mass spectrum imaging analysis.
The laser displacement sensor 81 is a small-sized laser displacement sensor HG-C1030 (working distance range is ±5mm, corresponding voltage range is 0-5V, there is positioning accuracy of 1 μm and repeated positioning accuracy of 10 μm), and the Arduino Uno development board 83 is combined to realize accurate control of the distance between the flowing liquid bridge and the tissue sample on the stage 400. Because the ADC sampling precision of the Arduino Uno development board 83 is only 10 bits, and the sampling resolution is insufficient to meet the positioning precision of the laser displacement sensor, the embodiment of the application is carried with the 16bit ADS1115 chip 82 and the Arduino Uno development board 83 to be matched for use, thereby realizing the acquisition of the high-precision laser displacement sensor signal.
Optionally, the micro-droplet extraction sampling mass spectrum imaging device based on laser displacement feedback further includes: and the pull tip assembly is used for carrying out pull tip on the front-stage capillary and the rear-stage capillary based on a preset pull tip strategy.
The preset pull-tip strategy may be related conditions set by those skilled in the art according to the sampling requirement, and is not specifically limited herein.
Specifically, as shown in fig. 3, in order to further reduce the size of the sampling flowing liquid bridge and improve the spatial resolution of imaging, in the embodiment of the present application, the front-stage capillary 200 and the rear-stage capillary 300 are subjected to a tapering process, and in the process, first, the front-stage capillary 200 and the rear-stage capillary 300 are placed in a V-shape, and a solvent is injected into the front-stage capillary 200 through the micro-injection pump 100, and flowing micro-droplets are formed between the front-stage capillary 200 and the rear-stage capillary 300; secondly, the relative positions of the front capillary and the rear capillary and the mass spectrum sample inlet are adjusted and aligned through observation and manual debugging, the micro injection pump 100 is used for feeding solution from the front capillary 200, the high pressure loaded on the front capillary 200 and the pneumatic auxiliary device 600 connected to the rear capillary 300 are started to adjust the size of a liquid bridge, and the mass spectrometer 800 is started to test the stability of spray signals.
Specifically, the outer diameter of the fore-stage capillary 200 is 363 μm, the inner diameter is 120 μm, after the tensile force is uniformly applied to the two ends of the fore-stage capillary 200, the glass capillary is melted by using a flame spray gun, the fore-stage capillary 200 is rapidly sharpened under the tensile force action of the two ends, and the outer diameter is reduced to between 25 and 35 μm after polishing; the latter stage capillary 300 is treated in the same manner as described above. By the method, the embodiment of the application can reduce the size of the sampling liquid bridge from about 200 mu m to about 20-30 mu m, thereby improving the spatial resolution.
Optionally, the post-stage capillary 300 is connected to the pneumatic auxiliary device 600 by a T-shaped tee, the first end and the second end of the T-shaped tee are both connected to the post-stage capillary 300, and the third end of the T-shaped tee is connected to the pneumatic auxiliary device 600, wherein the first end and the second end are both sealed by teflon pipes.
Specifically, in the embodiment of the present application, the pneumatic auxiliary device 600 is added to the post-stage capillary 300, the post-stage capillary 300 passes through the T-shaped tee and is connected to the first end and the second end of the T-shaped tee, meanwhile, the T-shaped tee is sealed by using a teflon tube, nitrogen is introduced to make the side close to the sampling end, and another teflon tube is sleeved on the glass capillary at the outlet end of the electrospray, so that a gas flow channel which can only be led out from the electrospray end is formed, wherein, due to different suction forces of interfaces of the mass spectrometer 800, the stable spraying of the helium gas flow rate of the pneumatic auxiliary device 600 can be adjusted, so as to improve the continuity and stability of the electrospray.
For example, as shown in fig. 4, in the embodiment of the present application, the performance of the laser displacement sensing feedback module 700 is tested by using a mouse brain sample, and fig. 4 (a) is a parameter read from the laser displacement sensor 81 by the Arduino u no development board 83 when scanning one line of data, wherein the scanning distance of the line is in the range of 0-12mm, and the distance set by the displacement feedback is in the range of 0.286-0.295 μm. There are two typical features during the scanning of the line; when the scanning starts, the distance parameter rises rapidly after a certain jitter, as shown in fig. 4 (c), until reaching the upper threshold setting limit of 0.295 μm, and then remains at the upper threshold position, and the inclination of the scanning platform at this time can be estimated to be 0.05 ° according to the slope parameter because of the upper threshold position caused by the inclination of the scanning platform. Due to the unevenness of the sample surface, there is also a fluctuation signal similar to that of fig. 4 (b) in the distance parameter during the scanning thereafter.
Further, taking m/z 782.6[ PC 34:1+Na ] + in a rat brain sample as an example for MS/MS analysis, firstly, placing a plurality of rat brain slices on a sample target, selecting a part of slices for signal test, and testing and optimizing a scanning equation of a mass spectrometer 800, a laser displacement sensing feedback module 700, a micro injection pump 100 speed, a gas speed of a gas auxiliary device 600, a scanning speed of a three-dimensional electric displacement platform 500, a liquid bridge size and stability to ensure the imaging spatial resolution and the stability of the laser displacement sensing feedback module 700; secondly, after the test is completed, the data acquisition is performed on the mouse brain slice through the folding circulation path scanning as shown in fig. 5, and in the acquisition process, the scanning speed of the three-dimensional electric displacement platform 500 needs to be ensured to be matched with the scanning time sequence of the mass spectrometer 800 so as to ensure that the information of each spatial point position is correct and facilitate the processing of the subsequent imaging data. The final imaging result is shown in fig. 6, fig. 6 (a) is a hematoxylin-eosin staining picture of the rat brain, and fig. 6 (b) is an imaging reduction result of the diagnostic ion m/z 599.3, so that the overall imaging profile reduction effect is better, the internal overall structure is clear, and the imaging quality is higher.
In summary, the embodiment of the application has the following beneficial effects:
(1) The application adds the laser displacement feedback module, realizes the control of micron-scale precision through real-time distance monitoring and feedback control in the Nano-DESI imaging process, and well solves the problems that a liquid bridge breaks away from the surface of a sample in the scanning process or front and rear capillaries collide with the sample due to the inclination of an electric displacement table or the unevenness of the surface of the sample with low cost.
(2) The application also solves the problems that stable pumping force is difficult to provide in mass spectrum such as discontinuous sample injection and the like and electrospray is unstable when bubbles appear in a capillary tube by adding the pneumatic auxiliary device.
(3) The application performs the tip pulling treatment on the front and rear capillaries, changes the size of the liquid bridge from 200 mu m to 20-30 mu m, and improves the imaging spatial resolution.
According to the micro-droplet extraction sampling mass spectrum imaging device based on laser displacement feedback, a micro-injection pump is used for continuously feeding a solution into a front-stage capillary tube, a flowing liquid bridge is formed between the micro-injection pump and a rear-stage capillary tube, an adjusting signal is generated when the distance between the flowing liquid bridge and a tissue sample on an objective table does not meet a preset condition by using a laser displacement sensing feedback module, the distance is adjusted to be a target sampling distance by using a three-dimensional electric displacement platform, micro-droplet extraction sampling is performed on the tissue sample, a sample to be analyzed is obtained, a high-voltage electric spray is formed between the rear-stage capillary tube and a mass spectrometer by using a pneumatic auxiliary device, the sample to be analyzed is ionized and then fed into the mass spectrometer, and mass spectrometry is performed on the ionized sample to be analyzed by using the mass spectrometer, so that an imaging result of the sample to be analyzed is obtained. Therefore, the problems that the relative distance between the sampling liquid bridge and the sample surface is difficult to control accurately, the electrospray stability is low, the imaging spatial resolution is low and the cost is high in the imaging process are solved, the micron-scale precision control and the electrospray stability of the relative distance between the sampling liquid bridge and the sample surface in the imaging process are realized by adding the laser displacement feedback module and the pneumatic auxiliary device, and the imaging spatial resolution is improved by carrying out the tip pulling treatment on the front capillary and the rear capillary.
Next, a micro-droplet extraction sampling mass spectrometry imaging method based on laser displacement feedback according to an embodiment of the application is described with reference to the accompanying drawings.
Fig. 7 is a flow chart of a micro-droplet extraction sampling mass spectrometry imaging method based on laser displacement feedback according to an embodiment of the application.
As shown in fig. 7, the method for micro-droplet extraction sampling mass spectrometry imaging based on laser displacement feedback adopts the micro-droplet extraction sampling mass spectrometry imaging device based on laser displacement feedback according to the above embodiment, and the method comprises the following steps:
in step S701, the solution is continuously fed into the pre-stage capillary by the micro-injection pump, so that a flowing liquid bridge is formed between the pre-stage capillary and the post-stage capillary;
in step S702, generating an adjustment signal when the distance between the flowing liquid bridge and the tissue sample on the objective table does not meet a preset condition by using the laser displacement sensing feedback module;
in step S703, adjusting the distance to be a target sampling distance according to the adjustment signal by the three-dimensional electric displacement platform, so as to perform micro-droplet extraction sampling on the tissue sample, thereby obtaining a sample to be analyzed;
in step S704, a high-pressure electric spray is formed between the rear capillary and the mass spectrometer by using a pneumatic auxiliary device, so that the sample to be analyzed is ionized and then sent to the mass spectrometer; and
in step S705, mass spectrometry is performed on the ionized sample to be analyzed by a mass spectrometer, and an imaging result of the sample to be analyzed is obtained.
Optionally, the micro-droplet extraction sampling mass spectrometry imaging method based on laser displacement feedback further includes:
and (3) carrying out drawing on the front-stage capillary and the rear-stage capillary based on a preset drawing strategy.
According to the micro-droplet extraction sampling mass spectrum imaging method based on laser displacement feedback, a micro-injection pump is used for continuously feeding a solution into a front-stage capillary tube, a flowing liquid bridge is formed between the micro-injection pump and a rear-stage capillary tube, an adjusting signal is generated when the distance between the flowing liquid bridge and a tissue sample on an objective table does not meet a preset condition by using a laser displacement sensing feedback module, the distance is adjusted to be a target sampling distance by using a three-dimensional electric displacement platform, micro-droplet extraction sampling is performed on the tissue sample, a sample to be analyzed is obtained, a high-voltage electric spray is formed between the rear-stage capillary tube and a mass spectrometer by using a pneumatic auxiliary device, the sample to be analyzed is ionized and then fed into the mass spectrometer, and mass spectrometry is performed on the ionized sample to be analyzed by using the mass spectrometer, so that an imaging result of the sample to be analyzed is obtained. Therefore, the problems that the relative distance between the sampling liquid bridge and the sample surface is difficult to control accurately, the electrospray stability is low, the imaging spatial resolution is low and the cost is high in the imaging process are solved, the micron-scale precision control and the electrospray stability of the relative distance between the sampling liquid bridge and the sample surface in the imaging process are realized by adding the laser displacement feedback module and the pneumatic auxiliary device, and the imaging spatial resolution is improved by carrying out the tip pulling treatment on the front capillary and the rear capillary.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or N embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
While embodiments of the present application have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the application, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the application.
Claims (9)
1. The utility model provides a little liquid drop extraction sampling mass spectrum image device based on laser displacement feedback which characterized in that includes: a microinjection pump, a front stage capillary, a rear stage capillary, an objective table, a three-dimensional electric displacement platform, a pneumatic auxiliary device, a laser displacement sensing feedback module and a mass spectrometer, wherein,
the microinjection pump is used for continuously feeding the solution into the pre-stage capillary tube so that a flowing liquid bridge is formed between the pre-stage capillary tube and the post-stage capillary tube;
the laser displacement sensing feedback module is used for generating an adjusting signal when the distance between the flowing liquid bridge and the tissue sample on the objective table does not meet the preset condition;
the three-dimensional electric displacement platform is used for adjusting the distance to be a target sampling distance according to the adjusting signal so as to conduct micro-droplet extraction sampling on the tissue sample to obtain a sample to be analyzed;
the pneumatic auxiliary device is used for forming high-pressure electric spray between the rear-stage capillary and the mass spectrometer so as to ionize the sample to be analyzed and send the ionized sample to the mass spectrometer; and
the mass spectrometer is used for carrying out mass spectrometry on the ionized sample to be analyzed to obtain an imaging result of the sample to be analyzed.
2. The apparatus of claim 1, wherein the pre-stage capillary and the post-stage capillary are placed in a V-shape.
3. The apparatus of claim 1, wherein the laser displacement sensing feedback module comprises:
the laser displacement sensor is used for collecting the distance between the flowing liquid bridge and the tissue sample on the objective table;
the conversion unit is used for converting the distance and then sending the converted distance to the judgment unit;
the judging unit is used for judging whether the converted distance meets the preset condition or not, and sending a control signal to the three-dimensional electric displacement platform when the converted distance does not meet the preset condition.
4. The apparatus as recited in claim 1, further comprising:
and the pull tip assembly is used for carrying out pull tip on the pre-stage capillary and the post-stage capillary based on a preset pull tip strategy.
5. The device of claim 1, wherein the rear stage capillary tube is connected to the pneumatic auxiliary device by a T-shaped tee, a first end and a second end of the T-shaped tee are connected to the rear stage capillary tube, and a third end of the T-shaped tee is connected to the pneumatic auxiliary device.
6. The device of claim 5, wherein the first end and the second end are sealed with teflon tubing.
7. The apparatus of claim 1 wherein the helium flow rate of the pneumatic assist device is determined by the draft of the mass spectrometer.
8. A method for micro-droplet extraction sampling mass spectrometry imaging based on laser displacement feedback, characterized in that the micro-droplet extraction sampling mass spectrometry imaging device based on laser displacement feedback according to any one of claims 1 to 7 is used, the method comprising the following steps:
continuously feeding a solution into the pre-stage capillary by the microinjection pump, so that a flowing liquid bridge is formed between the pre-stage capillary and the post-stage capillary;
generating an adjusting signal when the distance between the flowing liquid bridge and the tissue sample on the objective table does not meet a preset condition by utilizing the laser displacement sensing feedback module;
adjusting the distance to be a target sampling distance through the three-dimensional electric displacement platform according to the adjusting signal so as to extract and sample micro liquid drops of the tissue sample to obtain a sample to be analyzed;
forming high-pressure electric spray between the rear-stage capillary and the mass spectrometer by utilizing the pneumatic auxiliary device so as to ionize the sample to be analyzed and send the ionized sample to the mass spectrometer; and
and carrying out mass spectrometry on the ionized sample to be analyzed by the mass spectrometer to obtain an imaging result of the sample to be analyzed.
9. The method as recited in claim 8, further comprising:
and carrying out drawing on the front-stage capillary and the rear-stage capillary based on a preset drawing strategy.
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