CN106124388A - Capillary sample inlet system and sample injection method, unicellular electrology characteristic detecting system - Google Patents

Abstract

The invention provides a capillary tube sampling system, a sampling method, and a single-cell electrical characteristic detection system. The capillary sampling system includes: a syringe pump, a capillary, a microfluidic chip and a negative pressure module. The microfluidic chip is sequentially provided with a compression channel, a cell recovery channel and a negative pressure channel, and the three constitute the microchannel of the microfluidic chip; The front end of the compression channel is used as the liquid inlet of the microchannel, and its back end is connected to the liquid outlet of the microchannel through the cell recovery channel and the negative pressure channel, and the negative pressure module is connected to the liquid outlet of the microchannel; the back end of the capillary is connected to To the syringe pump, the suction and discharge of the cell suspension is controlled by the syringe pump. The cell suspension dripped into the microchannel liquid inlet side by the capillary, under the negative pressure provided by the negative pressure module, the cell suspension enters the compression chamber in turn. channel and cell recovery channel. The invention can effectively reduce the loss rate of samples, realize high recovery rate, and can be used for the detection of electrical characteristics of cell mass and rare cell samples.

Description

Capillary sampling system and sampling method, single cell electrical characteristic detection system

technical field

The invention relates to the field of microfluidic technology, in particular to a capillary sampling system, a sampling method, and a single-cell electrical characteristic detection system.

Background technique

Single-cell electrical properties, such as cell membrane specific capacitance and cytoplasmic conductivity, are of great significance and potential value for understanding cell function and state. As a marker-free cell feature, it can be used to define and classify cells.

In the study of single-cell electrical properties, the cell is equivalent to a capacitor-resistance network, in which the cell membrane with a bilayer phospholipid structure is equivalent to a capacitor, and the cytoplasm mainly composed of electrolytes is equivalent to a resistor. Considering that cells vary in size, cell-to-cell comparisons can only be made using cell membrane capacitance per unit area and cytoplasmic conductivity that are independent of cell size.

The traditional methods for studying the electrical characteristics of single cells mainly include patch clamp, etc., which can obtain the specific capacitance of the cell membrane, but the test efficiency is very low, so the throughput is low.

Microfluidic technology is an important science and technology in this century. Because its channel size is comparable to the linear size of mammalian cells, it can facilitate the manipulation of cells and has been widely used in the research of cell biophysics. On the microfluidic chip, the micro-manipulation method is generally used to drive the cells to clamp or flow between the electrodes, and the electrical characteristics of the cells can be reversed by the change of the impedance between the electrodes during the test.

However, in the prior art, when microfluidic chips are used to study the electrical characteristics of single cells, the method of sucking the cells between the electrodes is usually used. Although the throughput is higher than that of the traditional method, it is still very low. Microimpedance flow cytometry with flow between electrodes measures changes in impedance as cells flow through a channel with electrodes placed on one or both sides. In this type of method, the flow channel is a non-compressed channel (that is, the cross-sectional area of the channel is smaller than the cross-sectional area of the cell). Although the throughput is greatly improved, the leakage current between the electrodes in the test system is large and there is a lack of electrical models. , the electrical properties of single cells independent of cell size cannot be obtained.

In addition, based on the pure microfluidic technology of the compressed channel, the cells in the microfluidic sampling channel are driven by negative pressure to flow through a process whose cross-sectional area is smaller than that of the compressed channel, and the stretched length of the cells and the impedance at both ends of the compressed channel are measured, combined with electrical The model obtains single-cell electrical characteristic parameters. Although a certain throughput of single-cell electrical characteristic parameters independent of cell size can be obtained, the cell loss rate is high due to the existence of fluid dead zones in the microfluidic sampling channel, and a large investment is required. The number of cells measured is two to three orders of magnitude larger than the number of cells, and many cells, such as circulating tumor cells (CTCs), are rare and cannot provide a large number of cells for testing.

Therefore, it is of great practical value and practical significance to seek a single-cell electrical characteristic detection system independent of cell size with a very low loss rate and statistical significance.

Contents of the invention

(1) Technical problems to be solved

In view of the above technical problems, the present invention provides a capillary sampling system, a sampling method, and a single cell electrical characteristic detection system, so as to improve the detection throughput and reduce the loss rate.

(2) Technical solution

An aspect of the embodiments of the present invention provides a capillary sampling system. The capillary sampling system includes: a syringe pump, a capillary, a microfluidic chip and a negative pressure module, wherein: the microfluidic chip is sequentially provided with a compression channel, a cell recovery channel and a negative pressure channel, and the three constitute the microfluidic chip. channel; the front end of the compression channel is used as the liquid inlet of the microchannel, and its rear end is connected to the liquid outlet of the microchannel through the cell recovery channel and the negative pressure channel, and the negative pressure module is connected to the liquid outlet of the microchannel; the rear end of the capillary The end of the microchannel is connected to the syringe pump, and the suction and discharge of the cell suspension are controlled by the syringe pump. The cell suspension dripped into the side of the microchannel liquid inlet by the capillary, under the negative pressure provided by the negative pressure module, the cell suspension is sequentially Enter the compression channel and the cell recovery channel.

Another aspect of the embodiments of the present invention also provides a sampling method for a capillary sampling system. The sampling method includes: sucking the cell suspension into the capillary; and moving the capillary to the vicinity of the liquid inlet of the compression channel to discharge the liquid.

Another aspect of the embodiments of the present invention also provides a single cell electrical characteristic detection system. The single-cell electrical characteristic detection system includes: the above-mentioned capillary tube sampling system, wherein the microfluidic chip includes: a transparent substrate and a carrier tightly combined with it, and a compression channel, a cell recovery channel and a negative pressure channel are formed in the carrier; The detection module is used to observe the situation of the cells in the cell suspension passing through the compressed channel through the transparent substrate on the bottom surface of the microfluidic chip; the impedance measurement module is connected to the liquid inlet and the liquid outlet of the microchannel respectively. Electrodes for measuring the impedance properties of the cell suspension.

(3) Beneficial effects

It can be seen from the above technical scheme that the capillary sampling system, the sampling method, and the single-cell electrical characteristic detection system of the present invention have the following beneficial effects:

(1) Combining microfluidic technology with capillary micromanipulation technology, the sample is directly injected into the compression channel port of the microfluidic chip used to detect the electrical characteristics of single cells through the capillary, realizing the detection of electrical characteristics of single cells. In terms of detection throughput and detection data validity, it is comparable to the reported pure microfluidic detection technology based on compressed channels.

(2) Compared with the pure microfluidic chip detection method that has been reported based on the compression channel, the method based on capillary injection can effectively reduce the loss rate of the sample and achieve a high recovery rate (or extremely low loss rate, which is considered The number of cells measured is in the same order of magnitude as the number of cells input), which can be used for the detection of electrical characteristics of cell mass and its rare cell samples. This is a pure microfluidic detection technology based on compressed channels that has been reported. Can't do it.

Description of drawings

1 is a schematic structural diagram of a single-cell electrical characteristic detection system based on capillary sampling according to an embodiment of the present invention;

Fig. 2 is a flowchart of the fabrication process of the microfluidic chip in the single-cell electrical characteristic detection system shown in Fig. 1;

Fig. 3 is a schematic diagram of the cross section of the device after performing various steps in the fabrication process of the microfluidic chip shown in Fig. 2;

Fig. 4 is a flow chart of the operation method of the single-cell electrical characteristic detection system shown in Fig. 1;

FIG. 5 is a flow chart of the microfluidic chip in the operation method of the single cell electrical characteristic detection system shown in FIG. 4 .

detailed description

The present invention combines the microfluidic chip technology with the capillary micro-manipulation technology, and directly absorbs the concentrated micro-cell suspension by using the capillary to directly inject the cells to be tested into the compression channel inlet of the microfluidic chip for electrical characteristic detection. A high-throughput, high-recovery single-cell electrical characteristic detection system that can be applied to a very small number of cells is designed.

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

One aspect of the embodiments of the present invention provides a single-cell electrical characteristic detection system based on capillary sampling. Please refer to Figure 1, the single cell electrical characteristic detection system includes: a syringe pump, a capillary, a microfluidic chip, a negative pressure module, an impedance measurement module and an image detection module.

Wherein, the compression channel and the cell recovery channel along the horizontal direction, and the negative pressure channel along the vertical direction are arranged in the microfluidic chip. The compression channel, the cell recovery channel and the negative pressure channel constitute the microchannel of the microfluidic chip. Wherein, the front end of the compression channel is used as the liquid inlet of the microchannel, and its rear end is connected to the liquid outlet of the microchannel through the cell recovery channel and the negative pressure channel. The negative pressure module provides the driving force for the cell suspension flowing through the microchannel.

The cell suspension dripped from the capillary at the liquid inlet side of the microchannel, under the negative pressure provided by the negative pressure module located on the side of the negative pressure channel, the cell suspension enters the compression channel and the cell recovery channel in turn. The image detection module observes the situation that the cells in the cell suspension pass through the compression channel on the bottom surface of the microfluidic chip. The impedance measuring module is respectively connected with electrodes at the liquid inlet and the liquid outlet of the microchannel to measure the impedance characteristics of the cell suspension.

Each component of the single-cell electrical characteristic detection system of this embodiment will be described in detail below.

In this embodiment, the capillary refers to a pipe with a very thin diameter (generally less than 1mm), and its material is generally glass or organic polymer material. Between 20 μm and 60 μm (guaranteed to be larger than the cell diameter); the liquid volume of the front end detail is between 10 μL and 100 μL, which has the characteristics of being able to control the liquid volume of μL level. Wherein, the capillary is installed and fixed on a three-dimensional motion platform, and the rear end is connected to a syringe pump. In actual work, the three-dimensional motion platform can move the capillary mouth near the liquid inlet of the microchannel, and the cell suspension can be sucked and spit out through the syringe pump connected to the back end.

Please refer to FIG. 1 , the microfluidic chip includes: a transparent substrate and a carrier tightly combined with the substrate. The above-mentioned compression channel, cell recovery channel and negative pressure channel are formed in the carrier body.

The transparent substrate can be a transparent sheet material such as a glass slide, a glass slide, or a polydimethylsiloxane (polydimethylsiloxane, PDMS) sheet, and the above-mentioned material ensures that the bottom of the compression channel and the cell recovery channel is transparent, thereby Cell flow can be easily observed with a microscope or video camera. Of course, if it is only necessary to measure the electrical properties of a single cell and the flow of the cells is not concerned, the substrate can also be made of other non-transparent materials.

In this embodiment, the material of the carrier is PDMS. It should be clear to those skilled in the art that in addition to PDMS, transparent plastic materials such as plexiglass and SU-8 can also be used to form the above carrier by injection molding.

The carrier is injection molded from PDMS material, and the compression channel, cell recovery channel and negative pressure channel are formed during the injection molding process. Wherein, the cross sections of the compression channel, the cell recovery channel and the negative pressure channel are circular or oval.

The diameter of a single cell is generally 10 μm to 30 μm, and correspondingly, its cross-sectional size is between 80 μm ² and 700 μm ² . For the compression channel, its cross-sectional area is about 40%-90% of the cell cross-sectional area (about 40-600μm ² ), while for the cell recovery channel and negative pressure channel, its cross-sectional size is larger than Cross-sectional dimensions of single cells. Wherein, the compression channel and the cell recovery channel are arranged along the horizontal direction, and the end of the cell recovery channel is upwardly connected to the liquid outlet of the microfluidic chip through the approximately vertical negative pressure channel 25 .

In this embodiment, the microfluidic chip is a PDMS-based double-layer compression channel, which is manufactured by microfabrication technology. The manufacturing method of the microfluidic chip for detecting the electrical characteristics of the cells will be described in detail below, please refer to Figure 1 and Figure 2, the manufacturing method includes:

Step S202: making a seed layer with photoresist SU-85;

The glass slide was washed in acetone, ethanol and deionized water in sequence, and after drying, the surface was evenly spin-coated with a layer of SU-85, and exposed to form a seed layer.

Step S204: making a compression channel layer with photoresist SU-85;

On the seed layer, apply a layer of SU-85 evenly, and put on the mask plate for exposure, as shown in (A) in Figure 3.

Step S206: making a cell recovery channel layer with photoresist SU-8 25;

Apply a layer of SU-8 25 evenly on SU 8-5, put on a mask for exposure, as shown in (B) in Figure 3;

Step S208: developing, forming the SU-8 positive mold of the compression channel and the cell recovery channel;

The photoresist was developed using the SU-8 developer to form a SU-8 positive mold with a two-layer structure of compression channels and cell recovery channels, the structure of which is shown in Figure 3 (C).

Step S210: Pouring, mold turning and punching of PDMS;

Use the SU-8 male mold with double-layer structure as the mold to cast PDMS, turn over the mold after curing to obtain the PDMS overturned mold of the compression channel and the cell recovery channel, and punch a hole at the end of the cell recovery channel that is not connected to the compression channel to form a negative pressure Channel, its structure is shown in (D) in Figure 3.

Step S212: PDMS drilling and compression channel opening cutting;

The PDMS device was cut along the mouth of the compression channel, and one end of the compression channel was opened, which was used to detect the single-cell electrical characteristics of the inhaled cells in later experiments. Its structure is shown in Figure 3 (E).

Step S214: bonding PDMS to glass to form a microfluidic chip;

After the cut PDMS device is cleaned, it is bonded with a glass sheet to form a device, and its structure is shown in (F) in Figure 3 .

Please refer to FIG. 1 , in this embodiment, the negative pressure module includes: a closed hose and a negative pressure source. Wherein, the airtight hose is a T-shaped hose, the first end of which is inserted into the negative pressure channel, the second end is connected to the negative pressure source, and the third end is connected to the fluid discharge end. Under the action of negative pressure provided by the negative pressure source, the cells to be tested are deformed and pass through the compression channel, and then enter the cell recovery channel.

In this embodiment, the image detection module is used to observe and shoot the process of the cells to be tested in the sample to be tested passing through the compression channel under the action of negative pressure. Please refer to Figure 1, the image detection module includes: a biological inverted microscope and a camera. Wherein, the imaging element of the biological inverted microscope is aligned with the compressed channel from the back of the transparent glass substrate, and is used to convert tiny channel images and cell images into an image size that can be captured by the camera. The camera is aligned with the eyepiece of the biological inverted microscope, and is used to record the image information of cells deforming under negative pressure and passing through the compression channel through the biological inverted microscope.

In this embodiment, please refer to Figure 1. The first measuring electrode of the impedance measurement module extends into the sample to be tested at the liquid inlet of the microchannel, and the second measuring electrode extends into the sample to be measured in the negative pressure channel through a closed hose. in the sample. Through these two measuring electrodes, the impedance measurement module records the time-varying waveform of the impedance on both sides of the compression channel corresponding to two frequency points of low frequency and high frequency when the cells to be tested are deformed under the action of negative pressure and pass through the compression channel.

In this embodiment, the magnification of the biological inverted microscope is 400 times, and the scanning speed of the camera is 25 frames per second. The sampling frequency of the impedance analyzer is 25 sampling points per second, and the measurement frequency is 1kHz and 100kHz.

The single-cell electrical characteristic detection method based on compressed channels in the prior art generally includes three steps: experiment preparation, original impedance and image data acquisition and data processing. Among them, the sample preparation is mainly to prepare about 1 ml of cell suspension with a concentration of 10 ⁶ cells/ml, and the online measurement mainly includes directly dropping the suspension into the injection hole of the microfluidic chip with a pipette gun, and then performing collection cycles and other related procedures. Operation, data processing is to combine the raw data measured online with the data processing model and software platform to obtain the specific capacitance of the cell membrane and the conductivity of the cytoplasm of the single cell.

However, using the single-cell electrical characteristic detection system of this embodiment, it is only necessary to prepare about 10 microliters of cell suspension with a concentration of 10 ⁴ -10 ⁶ cells/ml in the suspension preparation stage, and suck it into the capillary by controlling the syringe pump, and then Synchronized sample injection during the test. Specifically, please refer to Figure 4, the operation method of the single-cell electrical characteristic detection system is as follows:

Step S402: preparing a cell suspension;

The cells in the obtained cell sample are dispersed and then suspended in cell culture medium or phosphate buffered saline (PBS for short). Put the suspension into a centrifuge tube, use a centrifuge to centrifuge the cells to gather at the bottom of the centrifuge tube, remove the supernatant and adjust the concentration according to the approximate number of cells, the concentration is configured at 10 ⁴ cells/ml to 10 ⁶ cells/ml It can be between ml.

Step S404: dropping the droplet of the cell suspension onto the liquid inlet of the microchannel;

Please refer to Figure 5, this step specifically includes:

Sub-step S404a: using a pipette gun to drop the cell suspension onto the hydrophobic surface;

This sub-step is specifically as follows: use a pipette gun to take 10 microliters of the prepared cell suspension and drop it on the surface that is convenient for capillary suction. In order to minimize the loss of cells during the transfer process, it is advisable to choose a hydrophobic surface as much as possible, such as Parafilm.

Sub-step S404b: Insert the front end of the capillary into the cell suspension droplet;

This sub-step is specifically as follows: the thick part of the capillary is connected to the syringe on the device and the syringe pump, and the thin end is inserted into the droplet of the cell suspension.

Sub-step S404c: adjust the syringe pump to the pumping mode, and suck the cell suspension liquid into the capillary;

This sub-step specifically includes: after the syringe pump is adjusted to the "refill" mode, all the cell suspension droplets taken out of the pipette gun are sucked into the capillary. In order to eliminate the hysteresis difference during the extraction and ejection of the capillary, before inhalation, the capillary, the back-end pipe, and the syringe can be filled with pure water and other solutions, and then the oil is sucked in to isolate the filling liquid from the cell suspension to form a filling Liquid-oil-cell suspension three-layer structure.

Sub-step S404d: moving the capillary near the liquid inlet of the compression channel to discharge the liquid;

This sub-step specifically includes: fixing the capillary on a three-dimensional motion platform, and using the three-dimensional motion platform to move the capillary near the mouth of the compression channel to spit out the liquid;

So far, the droplet of the cell suspension is dropped to the liquid inlet of the microchannel.

Step S406: Install and adjust the image detection module, microfluidic chip, impedance measurement module and negative pressure module;

First, the prepared microfluidic chip is loaded on the stage of a biological inverted microscope, so that the compressed channel part in the microfluidic chip is in the middle of the field of view of the microscope;

Then, inject the same cell culture fluid (or PBS) as the cell suspension into the capillary from the liquid inlet of the microchannel to fill the microfluidic channel, and remove the air bubbles in the channel. And drop a drop of liquid on the outside of the liquid inlet, submerge the liquid inlet, and insert the electrode for impedance measurement.

Then, build the measuring instrument in the impedance measurement module, the camera in the image detection module, and the pressure calibrator in the negative pressure module. This part is consistent with the previous method of measuring the electrical characteristics of single cells based on microfluidics.

Finally, install one electrode in the impedance measurement module into the T-shaped pipe of the negative pressure module and insert it into the liquid outlet of the microfluidic chip to ensure effective contact between the electrode and the solution; the other electrode of the impedance measurement module is inserted into the microfluidic chip. In the liquid droplets on the side of the liquid inlet of the chip, the liquid in the microfluidic channel and the electrodes form a measurement circuit path.

At this point, the experiment preparation is completed.

Step S408: Conducting electrical characteristic test of the cells to be tested;

First, adjust the mode of the syringe pump connected to the capillary to "inject", start to push out the cell suspension in the capillary, and observe under the microscope whether cells start to flow out of the capillary.

When cells begin to flow out of the capillary, click the start measurement button of the single-cell electrical characteristic testing platform software to start the acquisition of impedance data and image data. When the cell suspension in the capillary has flowed out, stop the test.

Repeat step S408 until all cell samples are tested or the number of measured cells reaches the required number.

Step S410: Processing based on the raw data obtained by the data processing module to obtain the specific capacitance of the single cell membrane and the conductivity of the cytoplasm.

As for the specific method of data processing, reference may be made to relevant documents in this field, which will not be described in detail here.

Another aspect of the embodiments of the present invention also provides a capillary sampling system. The capillary sampling system includes: a syringe pump, a three-dimensional motion platform, a capillary, a microfluidic chip and a negative pressure module. Among them, a compression channel, a cell recovery channel and a negative pressure channel are sequentially arranged in the microfluidic chip, and the three constitute the microchannel of the microfluidic chip; The recovery channel and the negative pressure channel are connected to the liquid outlet of the microchannel, and the negative pressure module is connected to the liquid outlet of the microchannel. The rear end of the capillary is connected to the syringe pump, and the suction and discharge of the cell suspension are controlled by the syringe pump. The cell suspension dripped into the microchannel liquid inlet side of the capillary is provided by the negative pressure module. Under the action of negative pressure, the cell suspension enters the compression channel and the cell recovery channel sequentially. The capillary is fixed on the three-dimensional motion platform.

In this embodiment, the microfluidic chip includes: a transparent substrate and a carrier closely combined with it, and the compression channel, the cell recovery channel and the negative pressure channel are formed in the carrier. The compression channel and the cell recovery channel are along the horizontal direction, and the negative pressure channel is along the vertical direction. And, the cross-section of compression channel, cell recovery channel and negative pressure channel is circular or oval; The cross-sectional area of the pressure channel is larger than the cross-sectional area of the cells to be tested.

It can be seen that the capillary sampling system in this embodiment is actually a part used for sampling in the single cell electrical characteristic detection system in the previous embodiment. For detailed information about the structure of the capillary sampling system, reference may be made to the description of the previous embodiment.

A sampling method using the capillary sampling system described above is given below. The sampling method includes:

Use a pipette to drop the cell suspension onto the hydrophobic surface;

inserting the front end of the capillary into the cell suspension droplet;

The syringe pump is adjusted to the pumping mode, and the droplet of the cell suspension is sucked into the capillary; and

Move the capillary to the vicinity of the liquid inlet of the compression channel to discharge the liquid.

Preferably, before the step of sucking the cell suspension drop into the capillary, it also includes: sucking the filling liquid into the capillary; and sucking the oil into the capillary; wherein, after the cell suspension drop is sucked into the capillary, the A three-layer structure of filling liquid-oil liquid-cell suspension is formed in the capillary.

Likewise, for the details of the sampling method, reference may be made to the description of the previous embodiment, which will not be described in detail here.

So far, the present embodiment has been described in detail with reference to the drawings. Based on the above description, those skilled in the art should have a clear understanding of the capillary sampling system and sampling method, and the single cell electrical characteristic detection system of the present invention.

In addition, the above definitions of each element and method are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and those of ordinary skill in the art can easily modify or replace them, for example:

(1) The capillary driving part is not limited to the syringe pump, and air pressure driving and the like can be used.

(2) Choose to fill the capillary with or without filling liquid. If filled, it is optional to use oil droplets or other hydrophobic liquids for isolation.

(3) The droplet size of capillary injection is not limited to 10 microliters, and can be properly adjusted according to actual needs.

(4) The cross-section of the compression channel in the microfluidic chip is not limited to a rectangle, but can be replaced by trapezoidal, circular and other structures; the opening of the negative pressure channel is not limited to a circle, and can be replaced by a square, triangle, etc.

(5) Impedance measurement modules are not limited to lock-in amplifiers and function generators, and can be replaced by virtual instruments based on data acquisition cards.

In addition, those skilled in the art will appreciate that examples of parameters may be provided herein that include specific values, but these parameters need not be exactly equal to the corresponding values, but may approximate the corresponding values within acceptable error margins or design constraints . Moreover, the directional terms mentioned in the embodiments, such as "up", "down", "front", "rear", "left", "right", etc., are only referring to the directions of the drawings, and are not used to limit the direction of the present invention. protection scope of the invention. In the method embodiments, unless the steps are specifically described or must occur sequentially, the order of the above-mentioned steps is not limited to the above-listed, and can be changed or rearranged according to the desired design. The above embodiments can be mixed and matched with each other or with other embodiments based on design and reliability considerations, that is, technical features in different embodiments can be freely combined to form more embodiments.

In summary, the present invention combines microfluidic chip technology with capillary micromanipulation technology to provide a high-throughput, high-recovery single-cell electrical characteristic detection system applicable to a very small number of cells and its The operation method has strong practical value and application prospect.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. a capillary sample inlet system, it is characterised in that including: syringe pump, capillary tube, micro-fluidic chip and negative pressure module, Wherein:

Setting gradually pressure channel, cell recovery approach and negative pressure channel in described micro-fluidic chip, three forms micro-fluidic core The microchannel of sheet；Cell recovery approach and negative pressure are passed through as the inlet of microchannel, its rear end in the front end of described pressure channel Passage is connected to the liquid outlet of microchannel, and described negative pressure module is connected to the liquid outlet of this microchannel；

The rear end of described capillary tube is connected to described syringe pump, described syringe pump control carry out the suction of cell suspension and tell Go out, the cell suspension that described capillary tube instills in inlet side, microchannel, under the suction function that negative pressure module provides, cell Suspension sequentially enters pressure channel and cell recovery approach.

Capillary sample inlet system the most according to claim 1, it is characterised in that the internal diameter in thick portion, described capillary tube upper end is situated between Between 0.5mm～1mm, the internal diameter in thin portion, lower end is between 20 μm～60 μm, and the appearance liquid measure in thin portion, lower end is between 10 μ L-100 μ L Between.

Capillary sample inlet system the most according to claim 1, it is characterised in that also include: three-dimensional movement platform；

Wherein, described capillary tube is fixed in described three-dimensional movement platform.

Capillary sample inlet system the most according to any one of claim 1 to 3, it is characterised in that described pressure channel and In the horizontal direction, described negative pressure channel is vertically for cell recovery approach.

Capillary sample inlet system the most according to any one of claim 1 to 3, it is characterised in that described pressure channel, thin The cross section of born of the same parents' recovery approach and negative pressure channel is circular or oval；

The cross-sectional area of described pressure channel is the 40%-90% of the cross-sectional area of cell to be measured, described cell recovery approach and The cross-sectional area of negative pressure channel is more than the cross-sectional area of cell to be measured.

6. apply the sample injection method of capillary sample inlet system according to any one of claim 1 to 5 for one kind, it is characterised in that bag Include:

Cell suspending liquid is sucked in capillary tube；And

Capillary tube is moved discharge liquid near the inlet of pressure channel.

Sample injection method the most according to claim 6, it is characterised in that described cell suspending liquid is sucked the step in capillary tube Suddenly include:

Liquid-transfering gun is used to be dropped on hydrophobic surface by cell suspension drop；

The front end of described capillary tube is inserted in cell suspension drop；And

Described syringe pump is adjusted to into decimation pattern, cell suspension drop is sucked in capillary tube.

Sample injection method the most according to claim 7, it is characterised in that described by cell suspension drop suction capillary tube Also include before step:

Filling liquid is sucked in capillary tube；And

Fluid is sucked in capillary tube；

Wherein, after just cell suspension drop sucks in capillary tube, described capillary tube is formed filling liquid-fluid-cell and hangs Liquid three-decker.

9. a unicellular electrology characteristic detecting system, it is characterised in that including:

Capillary sample inlet system according to any one of claim 1 to 5, wherein, described micro-fluidic chip includes: transparent substrates And in the supporting body combined closely with it, described supporting body, form described pressure channel, cell recovery approach and negative pressure channel；

Image detection module, in the bottom surface of described micro-fluidic chip, through in described transparent substrates observation of cell suspension The cell situation by pressure channel；

Impedance measurement module, its inlet in microchannel and liquid outlet are connected to electrode, for the resistance to cell suspension Anti-characteristic measures.

Unicellular electrology characteristic detecting system the most according to claim 9, it is characterised in that described capillary sample inlet system In system, described negative pressure module includes: airtight flexible pipe and negative pressure source；

Wherein, described airtight flexible pipe is a T-shaped flexible pipe, and its first end inserts in the negative pressure channel of described micro-fluidic chip, and it is the years old Two ends are connected to negative pressure source, and its 3rd end for inserting the liquid of cell recovery approach by the second electrode of impedance measurement module In；

Wherein, during the first electrode of described impedance measurement module inserts the cell suspension of inlet side, microchannel.