Microfluidic chip and method for cell detection using the microfluidic chip

Abstract

The present invention discloses a microfluidic chip and a method for cell detection using the microfluidic chip. The microfluidic chip includes a chip body and a detection electrode group. A fluid channel is formed in the chip body. A first detection channel and a second detection channel are sequentially formed in the fluid channel along the flow direction of the fluid, and the diameter of the second detection channel is smaller than that of the first detection channel. The detection electrode group includes a first group of detection electrodes formed at both ends of the first detection channel and a second group of detection electrodes formed at both ends of the second detection channel. The microfluidic chip of the present invention and the method for cell detection using the microfluidic chip can simply and efficiently perform a more comprehensive viability detection on cells.

Description

Technical Field

[0001] The present invention relates to the field of biomedical microfluidic cell sorting technology, and particularly to a microfluidic chip for detecting cell viability using impedance measurement and a method for cell detection using the microfluidic chip. Background Art

[0002] General methods for judging cell viability are morphological identification and specific fluorescence staining detection. These basic methods are widely used in methods such as flow cytometry, microscopy technology, and image flow cytometry. Cell viability detection is also a very basic detection application in life science and medical diagnosis.

[0003] The method for detecting cell viability by morphology is mainly applied to a microscope platform or a high-end image flow detection platform. The microscope platform provides a classic detection scheme for a cell counting chamber, but the detection throughput of this method is very low, and the cell sample covered by the detection area on the cell counting chamber accounts for less than 1% of the total sample loading amount. The high-end flow cytometer provides the ability to detect cell morphology under all-throughput conditions, but this technical method depends on very expensive detectors and software.

[0004] Specific fluorescence staining is mainly based on specific cell dyes for specific fluorescence staining of cell nuclei or intracellular metabolic products. After staining the cell sample, detection is achieved on a flow cytometer platform. This method requires a large amount of pre-sample operations, and the costs of dyes and other reagents and flow cytometer equipment are relatively expensive, and the overall operation requirements are relatively high.

[0005] The information disclosed in this background art section is only intended to enhance the overall understanding of the present invention and should not be regarded as an admission or any form of suggestion that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0006] The purpose of the present invention is to provide a microfluidic chip for detecting cell viability using impedance measurement and a method for cell detection using the microfluidic chip, which can simply, efficiently, and more comprehensively detect the viability of cells.

[0007] To achieve the above purpose, an embodiment of the present invention provides a microfluidic chip for cell detection. The microfluidic chip includes a chip body and a detection electrode group. A fluid channel is formed in the chip body. A first detection channel and a second detection channel are sequentially formed in the fluid channel along the flow direction of the fluid. The diameter of the second detection channel is smaller than that of the first detection channel. The detection electrode group includes a first group of detection electrodes formed at both ends of the first detection channel and a second group of detection electrodes formed at both ends of the second detection channel.

[0008] In one or more embodiments of the present invention, the diameters of the first detection channel and the second detection channel are both smaller than the diameter of the fluid channel.

[0009] In one or more embodiments of the present invention, the diameter of the first detection channel is greater than the diameter of the cell to be detected.

[0010] In one or more embodiments of the present invention, the diameter of the second detection channel is not greater than the diameter of the cell to be detected.

[0011] In one or more embodiments of the present invention, the first group of detection electrodes includes a first detection electrode and a second detection electrode. The first detection electrode is located at the front end of the first detection channel in the fluid flow direction, and the second detection electrode is located at the rear end of the first detection channel in the fluid flow direction.

[0012] In one or more embodiments of the present invention, the second group of detection electrodes includes a third detection electrode and a fourth detection electrode. The third detection electrode is located at the front end of the second detection channel in the fluid flow direction, and the fourth detection electrode is located at the rear end of the second detection channel in the fluid flow direction.

[0013] In one or more embodiments of the present invention, the diameter of the first detection channel is 50 micrometers.

[0014] In one or more embodiments of the present invention, the diameter of the second detection channel is 20 micrometers.

[0015] An embodiment of the present invention also provides a method for cell detection using the above microfluidic chip, including: flowing the cell to be detected through the first detection channel; obtaining a first detection signal of a first group of detection electrodes at both ends of the first detection channel when the cell to be detected flows through the first detection channel; flowing the cell to be detected through the second detection channel; obtaining a second detection signal of a second group of detection electrodes at both ends of the second detection channel when the cell to be detected flows through the second detection channel; comparing the second detection signal with the first detection signal to determine the activity of the cell to be detected.

[0016] In one or more embodiments of the present invention, after obtaining the first detection signal, the size of the cell to be detected is determined according to the first detection signal.

[0017] In one or more embodiments of the present invention, the first detection signal is: an impedance change signal caused by a cell to be detected when passing through the first detection channel, wherein the impedance change is caused by the size of the cell to be detected itself; obtaining the first detection signal and judging the size of the cell to be detected according to the first detection signal, including: judging the size of the cell to be detected passing through the first detection channel according to the impedance change situation obtained by the first group of detection electrodes.

[0018] In one or more embodiments of the present invention, the second detection signal is: an impedance change signal caused by a cell to be detected when passing through the second detection channel, wherein the impedance change is caused by the size of the cell to be detected itself and the activity of the cell to be detected; obtaining the second detection signal, comparing the second detection signal with the first detection signal, and judging the activity of the cell to be detected, including: comparing the impedance change situation obtained by the second group of detection electrodes with the impedance change situation obtained by the first group of detection electrodes, and judging the activity of the cell to be detected passing through the second detection channel according to the comparison result.

[0019] Compared with the prior art, the microfluidic chip and the cell detection method according to the embodiments of the present invention have high integration, low application cost, simple equipment, and are typical label-free detection schemes. Compared with the existing cell activity detection technologies, they do not require complex manual operations before cell sampling, and provide more comprehensive impedance information. Moreover, they can even be combined with the existing fluorescence specific detection technologies to achieve the detection of cell activity or other characteristics from more angles. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of a microfluidic chip according to an embodiment of the present invention;

[0021] Figure 2 is a schematic flowchart of a method for cell detection using a microfluidic chip according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following will describe in detail the specific embodiments of the present invention with reference to the accompanying drawings. However, it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0023] Unless otherwise clearly stated, in the whole specification and claims, the term "comprise" or its variations such as "comprises" or "including" will be understood to include the stated elements or components, without excluding other elements or other components.

[0024] As mentioned in the background art, the existing methods for judging cell activity are morphological identification and specific fluorescence staining detection. Both of these methods rely on very expensive equipment or materials or software, and require a large amount of sample preparation operations, and the detection methods are relatively cumbersome.

[0025] To solve the above problems, the present invention creatively provides a microfluidic chip for detecting cell viability using impedance spectroscopy and a method for cell detection using the microfluidic chip, which can simply, efficiently and more comprehensively detect the viability of cells.

[0026] As Figure 1 shown, an embodiment of the present invention provides a microfluidic chip for cell detection, including a chip body 10 and a detection electrode group.

[0027] A fluid channel 11 is formed in the chip body 10, and the fluid channel 11 provides a channel for the cells to be detected to flow. A first detection channel 12 and a second detection channel 13 are sequentially formed in the fluid channel 11 along the flow direction of the fluid. The diameters of the first detection channel 12 and the second detection channel 13 are much smaller than the diameter of the fluid channel 11.

[0028] The detection electrode group includes a first group of detection electrodes 21 formed at both ends of the first detection channel 12, and a second group of detection electrodes 22 formed at both ends of the second detection channel 13.

[0029] When the cells to be detected flow through the first detection channel 12 and the second detection channel 13, the resistance of the first detection channel 12 and the second detection channel 13 will change. The first group of detection electrodes 21 at both ends of the first detection channel 12 and the second group of detection electrodes 22 at both ends of the second detection channel 13 respectively perform detection. Through signal amplification, acquisition and analysis, impedance information such as the size of the cells to be detected is obtained.

[0030] In the present embodiment, the diameter of the second detection channel 13 is smaller than the diameter of the first detection channel 12. Among them, the diameter of the first detection channel 12 is larger than the diameter of the cell to be detected; the diameter of the second detection channel 13 is not larger than the diameter of the cell to be detected. Exemplarily, the diameter of the first detection channel 12 is 50 microns, and the diameter of the second detection channel 13 is 20 microns. The impedance changes caused by the cells to be detected passing through the first detection channel 12 and passing through the second detection channel 13 will be somewhat different. In the process of passing through the first detection channel 12, the diameter of the cells to be detected (generally not more than 20 microns) is smaller than the diameter of the first detection channel 12, and the pressure of the fluid on the cells to be detected is relatively small, and a small deformation occurs. At this time, the impedance signal obtained by the first detection channel 12 is a resistance change signal that is positively correlated with the particle size of the cell. When the cell to be detected passes through the second detection channel 13, the diameter of the cell to be detected is close to that of the second detection channel 13, causing the cell to be detected to be subjected to greater pressure when passing through the channel. At this time, the overall deformation of the cell to be detected causes a change in the charge on the surface of the cell membrane. The voltage change measured in the second detection channel 13 not only includes the basic impedance of the size of the cell to be detected, but also includes the change in the surface charge of the cell membrane due to pressure. At the same time, the change in the surface charge caused by the pressure on the cell membrane will not occur or will not be significant under the condition of dead cells, so the activity of the cell to be detected can be distinguished.

[0031] The impedance change caused by the cell to be detected passing through the first detection channel 12 is V 1 The impedance change caused by the cell to be detected passing through the second detection channel 13 is V 2 +ΔV 2 Among them, V 1 、V 2 is the impedance change caused by the size of the cell to be detected, ΔV 2 Refers to the change signal of the cell membrane surface charge caused by the pressure on the cell to be detected. If the cell is dead, ΔV 2 The signal is very weak or no change.

[0032] The host computer calibrates the time axis to match all impedance change relationships generated by the first detection channel 12 and the second detection channel 13, and determines the cell size through the signal of the first detection channel 12, and determines whether the cell membrane charge changes under the conditions of the cell size through the signal of the second detection channel 13, and determines the activity of the cell to be detected by the level of the change.

[0033] In this embodiment, the first group of detection electrodes 21 includes detection electrode 1 211 and detection electrode 2 212. Detection electrode 1 211 is located at the front end of the first detection channel 12 in the flow direction of the fluid, and detection electrode 2 212 is located at the rear end of the first detection channel 12 in the flow direction of the fluid. The second group of detection electrodes 22 includes detection electrode 3 221 and detection electrode 4 222. Detection electrode 3 221 is located at the front end of the second detection channel 13 in the flow direction of the fluid, and detection electrode 4 222 is located at the rear end of the second detection channel 22 in the flow direction of the fluid.

[0034] like Figure 2 As shown, an embodiment of the present invention also provides a method for cell detection using the above-mentioned microfluidic chip, including: s1, allowing the cells to be detected to flow through a first detection channel; s2, obtaining a first detection signal from a first group of detection electrodes at both ends of the first detection channel when the cells to be detected flow through the first detection channel, and judging the size of the cells to be detected according to the first detection signal; s3, allowing the cells to be detected to flow through a second detection channel; s4, obtaining a second detection signal from a second group of detection electrodes at both ends of the second detection channel when the cells to be detected flow through the second detection channel; s5, comparing the second detection signal with the first detection signal to judge the activity of the cells to be detected.

[0035] The first detection signal is: an impedance change signal caused when the cell to be detected passes through the first detection channel, wherein the impedance change is caused by the size of the cell to be detected itself. In the process of passing through the first detection channel 12, the diameter of the cell to be detected (generally not more than 20 microns) is smaller than the diameter of the first detection channel 12, and the pressure of the fluid on the cell to be detected is relatively small, and a small deformation occurs. At this time, the impedance signal obtained by the first detection channel 12 is a resistance change signal that is positively correlated with the particle size of the cell. Obtaining the first detection signal and judging the size of the cell to be detected based on the first detection signal can specifically include: judging the size of the cell to be detected passing through the first detection channel based on the impedance change generated when the cell to be detected passes through the first detection channel obtained by the first group of detection electrodes.

[0036] The second detection signal is: an impedance change signal caused when the cell to be detected passes through the second detection channel, wherein the impedance change is caused by the size of the cell to be detected and the activity of the cell to be detected. When the cell to be detected passes through the second detection channel 13, the diameter of the cell to be detected is relatively close to the diameter of the second detection channel 13, causing the cell to be detected to pass through the channel under greater pressure. At this time, the overall deformation of the cell to be detected causes a change in the charge on the surface of the cell membrane. The voltage change measured in the second detection channel 13 not only includes the basic impedance of the size of the cell to be detected, but also includes the surface charge change of the cell membrane caused by the pressure. Obtaining a second detection signal, comparing the second detection signal with the first detection signal, and determining the activity of the cells to be detected, specifically may include: comparing the impedance change generated when the cells to be detected pass through the second detection channel obtained by the second group of detection electrodes with the impedance change generated when the cells to be detected pass through the first detection channel obtained by the first group of detection electrodes, and determining whether the cell membrane charge of the cells to be detected passing through the second detection channel has changed through the comparison result, and determining the activity of the cells to be detected through the change level; if the cells are dead, the change signal of the cell membrane surface charge caused by the compression of the cells to be detected is a very weak change or no change.

[0037] Compared with the prior art, the microfluidic chip and cell detection method of the embodiment of the present invention have high integration, low application cost, simple equipment, and are a typical label-free detection scheme. Compared with the existing cell activity detection technology, it does not require complicated manual operations before cell sampling, and provides more comprehensive impedance information. It can even be combined with the existing fluorescence-specific detection technology to achieve detection of cell activity or other characteristics from more angles.

[0038] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A microfluidic chip for cell detection, characterized in that, the microfluidic chip comprises: a chip body, in which a fluid channel is formed. In the fluid channel, a first detection channel and a second detection channel are sequentially formed along the fluid flow direction, and the diameter of the second detection channel is smaller than that of the first detection channel; a detection electrode group, including a first group of detection electrodes formed at both ends of the first detection channel and a second group of detection electrodes formed at both ends of the second detection channel; the diameter of the first detection channel is larger than the diameter of the cell to be detected; and the diameter of the second detection channel is not larger than the diameter of the cell to be detected.

2. The microfluidic chip according to claim 1, characterized in that, the diameters of both the first detection channel and the second detection channel are smaller than the diameter of the fluid channel.

3. The microfluidic chip according to claim 1, characterized in that, the first group of detection electrodes includes a first detection electrode and a second detection electrode. The first detection electrode is located at the front end of the first detection channel in the fluid flow direction, and the second detection electrode is located at the rear end of the first detection channel in the fluid flow direction.

4. The microfluidic chip according to claim 1, characterized in that, the second group of detection electrodes includes a third detection electrode and a fourth detection electrode. The third detection electrode is located at the front end of the second detection channel in the fluid flow direction, and the fourth detection electrode is located at the rear end of the second detection channel in the fluid flow direction.

5. The microfluidic chip according to claim 1, characterized in that, the diameter of the first detection channel is 50 microns; and / or, the diameter of the second detection channel is 20 microns.

6. A method for cell detection using the microfluidic chip according to any one of claims 1 to 5, characterized in that, it includes: letting the cell to be detected flow through the first detection channel; acquiring a first detection signal of the first group of detection electrodes at both ends of the first detection channel when the cell to be detected flows through the first detection channel. The first detection signal is an impedance change signal caused by the cell to be detected passing through the first detection channel, wherein the impedance change is caused by the size of the cell to be detected itself; letting the cell to be detected flow through the second detection channel; acquiring a second detection signal of the second group of detection electrodes at both ends of the second detection channel when the cell to be detected flows through the second detection channel. The second detection signal is an impedance change signal caused by the cell to be detected passing through the second detection channel, wherein the impedance change is caused by the size of the cell to be detected itself and the activity of the cell to be detected; comparing the second detection signal with the first detection signal to judge the activity of the cell to be detected, including: according to the impedance change situation obtained by the second group of detection electrodes, comparing it with the impedance change situation obtained by the first group of detection electrodes, and judging the activity of the cell to be detected passing through the second detection channel through the comparison result.

7. The cell detection method according to claim 6, characterized in that, after acquiring the first detection signal, judging the size of the cell to be detected according to the first detection signal.

8. The cell detection method according to claim 7, characterized in that obtaining the first detection signal and judging the size of the cell to be detected according to the first detection signal, including: judging the size of the cell to be detected passing through the first detection channel according to the impedance change obtained by the first group of detection electrodes.

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