Integrated pre-sorting cell mechanical and electrical multi-parameter joint detection device
阅读说明：本技术 一种集成预分选的细胞机械和电学多参数联合检测的装置 (Integrated pre-sorting cell mechanical and electrical multi-parameter joint detection device ) 是由 项楠 张孝哲 王斯林 周宇杰 于 2020-06-16 设计创作，主要内容包括：本发明公开了一种集成预分选的细胞机械和电学多参数联合检测的装置,包括预分选模块、聚焦模块、电检测模块和形变模块,预分选模块设置样品入口,样品入口下方连通螺旋流道,其末端的Y型双出口分别与聚焦模块和血细胞出口连通,聚焦模块将细胞聚焦为单列并增大两细胞间距,电检测模块对细胞进行宽频阻抗测量,细胞经电检测模块检测后进入形变模块,在形变模块内撞击壁面产生形变,进而对细胞的变形性进行分析。本发明对细胞进行机械和电学多参数联合检测,通过预分选模块去除绝大部分血细胞,同时借助电检测模块和形变模块实现循环肿瘤细胞和相近尺寸白细胞的精准鉴别,为癌症复发转移的临床诊断以及其他细胞学研究等提供一种快捷有效的方式。(The invention discloses a device for integrated pre-sorted cell mechanical and electrical multi-parameter combined detection, which comprises a pre-sorting module, a focusing module, an electrical detection module and a deformation module, wherein the pre-sorting module is provided with a sample inlet, a spiral flow channel is communicated below the sample inlet, a Y-shaped double outlet at the tail end of the spiral flow channel is respectively communicated with the focusing module and a blood cell outlet, the focusing module focuses cells into a single row and increases the distance between the two cells, the electrical detection module carries out broadband impedance measurement on the cells, the cells enter the deformation module after being detected by the electrical detection module, and impact wall surfaces in the deformation module to generate deformation so as to analyze the deformability of the cells. The invention carries out mechanical and electrical multi-parameter combined detection on cells, removes most blood cells through the pre-sorting module, and realizes accurate identification of circulating tumor cells and similar size white blood cells by means of the electrical detection module and the deformation module, thereby providing a quick and effective mode for clinical diagnosis of cancer recurrence and metastasis, other cytological researches and the like.)
1. An apparatus for integrated pre-sorted cellular mechanical and electrical multiparameter joint detection, characterized by: including sorting module, focus module, electric detection module and deformation module in advance, it is provided with sample entry (1) to sort the module in advance, sample entry (1) below intercommunication spiral runner (3), the end of spiral runner (3) is equipped with two exports of Y type (4), two exports of Y type (4) communicate with focus module and blood cell export (5) respectively, focus module is single row and increase the interval between the two adjacent cells with the cell focus, electric detection module is right focus module's cell carries out wide band impedance measurement, and the cell warp electric detection module detects the back and gets into deformation module striking wall produces deformation in the deformation module, and then carries out the analysis to the deformability of cell.
2. The device for integrated pre-sorted cellular mechanical and electrical multiparameter combined detection according to claim 1, characterized in that: the entrance of spiral runner (3) is provided with filter sieve (2), filter sieve (2) comprise the microcolumn array of equidistance range.
3. The device for integrated pre-sorted cellular mechanical and electrical multiparameter combined detection according to claim 1, characterized in that: the vertical section of the spiral flow channel (3) is rectangular with the width larger than the height or trapezoidal with two sides with different heights; when the vertical section of the spiral flow channel (3) is rectangular, the ratio of the height to the width of the spiral flow channel is 1/2-1/4.
4. The device for integrated pre-sorted cellular mechanical and electrical multiparameter combined detection according to claim 1, characterized in that: the focusing module focuses the cells into a single row through the arranged focusing sinusoidal flow channel (6), and then the distance between two adjacent cells is increased through the arranged sudden expansion structure (7).
5. The device for integrated pre-sorted cellular mechanical and electrical multiparameter combined detection according to claim 1, characterized in that: the deformation module is provided with two exports (10) of T type runner, the regional center of the T type runner of two exports (10) of T type runner is the region that the cell strikes the wall and produces the deformation.
6. The device for integrated pre-sorted cellular mechanical and electrical multiparameter combined detection of claim 5, wherein: and a narrowing structure (9) is arranged at the inlet of the double outlets (10) of the T-shaped flow channel, and cells impact the wall surface of the T-shaped flow channel area of the double outlets (10) of the T-shaped flow channel after passing through the narrowing structure (9).
7. The device for integrated pre-sorted cellular mechanical and electrical multiparameter combined detection of claim 5, wherein: and shooting the cell deformation of the T-shaped flow channel region in the double outlets (10) of the T-shaped flow channel by a high-speed camera.
8. The device for integrated pre-sorted cellular mechanical and electrical multiparameter combined detection of claim 4, wherein: the electric detection module is provided with an ITO electrode (8), the ITO electrode (8) is close to the outlet of the sudden expansion structure (7), and shielding electrodes are arranged around the ITO electrode (8).
9. The device for integrated pre-sorted cellular mechanical and electrical multiparameter combined detection of claim 4, wherein: the cross section of the focusing sinusoidal flow channel (6) is rectangular, and the size meets the requirement that the ratio of the height to the width is 1-1/3.
10. The device for integrated pre-sorted cellular mechanical and electrical multiparameter combined detection according to claim 2, characterized in that: the cross section of the micro-column is any one or combination of a circle, a triangle and an I shape.
Technical Field
The invention relates to a device for detecting multiple physical parameters of circulating tumor cells, in particular to a device for integrated pre-sorted mechanical and electrical multi-parameter joint detection of cells.
Background
In recent years, a circulating tumor cell sorting and enriching method based on a microfluidic technology has attracted extensive attention and made breakthrough progress. However, conventional analytical methods such as immunocytology, flow cytometry, and nucleic acid detection techniques are still commonly used for the identification and characterization of circulating tumor cells after sorting. In the methods, a biological molecular marker is taken as an analysis object, so that the cell activity is influenced, the detection of circulating tumor cells (tumor cells may have epithelial mesenchymal transformation in the transfer process and lose epithelial cell markers) which do not express a specific molecular marker cannot be realized, and the common defects of complex operation, low detection efficiency, difficulty in integration and the like exist.
The dielectric properties of biological cells are a useful marker indicative of the physiological and pathological state of the cell and can be characterized by measuring the electrical impedance signal of the cell suspension mixing system. By means of the micro-scale electrodes and the micro-fluidic single-cell impedance detection technology, the traditional impedance measurement method is introduced to the micro-fluidic chip and gradually develops and evolves into a micro coulter counter, a micro impedance analyzer and an impedance flow cytometer. The existing impedance flow cytometry still generally adopts a desk-top impedance analyzer to acquire a single-frequency impedance signal of a measured cell, so that the complexity of the whole detection system and the lack of cell impedance information are caused. In addition, although impedance flow cytometry or other methods can achieve separation of most blood cells and circulating tumor cells, some cells are misjudged, and thus other characteristics of the cells need to be considered for joint identification.
Research shows that the mechanical performance of cells is closely related to the pathological state of the cells, for example, cancer cells are softer than healthy cells. Thanks to the vigorous development of microfabrication technology, some microfluidic devices capable of analyzing the mechanical properties of single cells have been developed successfully, such as measuring the deformability of cells using dielectrophoresis-induced deformation technology, analyzing the mechanical response of cells by the action of compressive, tensile and fluid shear stresses, and characterizing the contractile force of cells by patterning the substrate of microcolumns. The microfluidic platforms can effectively analyze the mechanical characteristics of single cells, but the cells need to be captured and fixed in the experimental process, so that the whole measurement process consumes a long time, and the detection flux of the devices is greatly limited.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to provide a simplified broadband impedance measurement system, which realizes multi-frequency alternating current impedance detection of focused cells; meanwhile, the device can also be used for detecting the mechanical performance of cells by utilizing the deformation generated by the impact of the captured cells on the wall surface of the T-shaped flow channel and integrating the pre-sorting of the mechanical and electrical multi-parameter combined detection of the cells.
The technical scheme is as follows: the cell broadband impedance measurement device comprises a pre-sorting module, a focusing module, an electrical detection module and a deformation module, wherein the pre-sorting module is provided with a sample inlet, the lower part of the sample inlet is communicated with a spiral flow channel, the tail end of the spiral flow channel is provided with a Y-shaped double outlet, the Y-shaped double outlet is respectively communicated with the focusing module and a blood cell outlet, the focusing module focuses cells into a single row and increases the distance between two adjacent cells, the electrical detection module performs broadband impedance measurement on the cells of the focusing module, the cells enter the deformation module after being detected by the electrical detection module, the wall surface is impacted in the deformation module to generate deformation, and the deformation of the cells is analyzed.
A filter sieve is arranged at an inlet of the spiral flow passage and consists of microcolumn arrays arranged at equal intervals; can block large particle impurities and avoid the blockage of the flow channel of the device.
The vertical section of the spiral flow channel is rectangular with the width larger than the height or trapezoidal with two sides with different heights; when the vertical section of the spiral flow channel is rectangular, the ratio of the height to the width of the spiral flow channel is 1/2-1/4.
The focusing module focuses the cells into a single row through the arranged focusing sinusoidal flow channel, and then the distance between two adjacent cells is increased through the arranged sudden expansion structure, so that interference generated when the two cells collide the wall is avoided.
The deformation module is provided with two outlets of a T-shaped flow channel, and the center of the T-shaped flow channel area of the two outlets of the T-shaped flow channel is an area where cells impact a wall surface to generate deformation.
And a narrow structure is arranged at the inlet of the double outlets of the T-shaped flow channel, and cells impact the wall surface of the central area of the T-shaped flow channel of the double outlets of the T-shaped flow channel after passing through the narrow structure.
And shooting the cell deformation of the T-shaped flow channel region in the double outlets of the T-shaped flow channel by using a high-speed camera.
The electric detection module is provided with an ITO electrode, the ITO electrode is close to an outlet of the sudden expansion structure, and shielding electrodes are arranged around the ITO electrode to reduce the interference of the external environment on the measurement electric signal.
The cross section of the focusing sinusoidal flow channel is rectangular, and the size meets the requirement that the ratio of the height to the width is 1-1/3.
The cross section of the micro-column is any one or combination of a circle, a triangle and an I shape; due to the structural design, impurities larger than the corresponding size can be captured when flowing through, and the risk of blocking a flow channel is reduced.
Has the advantages that: compared with the prior art, the invention has the beneficial effects that: (1) by integrating cell deformability detection and cell impedance detection, multi-parameter combined detection of cells is realized, experiment and detection time is greatly reduced, and cell identification is more accurate; (2) the cell impacts the wall surface to generate deformation, so that the cell is more stressed and is more easily deformed; in addition, the deformation mode greatly improves the detection flux, and has higher detection flux and more obvious cell deformation compared with the denaturation modes such as dielectrophoresis induced deformation, atomic force microscopic deformation, microtubule sucking and the like; (3) low cost, simple operation and easy integration and miniaturization.
Drawings
FIG. 1 is a top view of the overall structure of the present invention;
FIG. 2 is a partially enlarged view of a micropillar array according to the present invention;
FIG. 3 is a schematic diagram of the principle of spiral flow channel inertial sorting according to the present invention;
FIG. 4 is a schematic view of an electrical detection process of the present invention;
FIG. 5 is a schematic view of a process of local amplification and cell deformation of a T-shaped flow channel according to the present invention;
FIG. 6 is a diagram showing a cell deformation in the T-shaped flow channel in the example;
FIG. 7 is the impedance spectrum of the 1M frequency AC signal of the white blood cells and cancer cells in the example.
Detailed Description
The invention is described in further detail below with reference to specific embodiments and the attached drawings.
As shown in figure 1, the device comprises a pre-sorting module, a focusing module, an electrical detection module and a deformation module, wherein the pre-sorting module is provided with a sample inlet 1, a spiral flow channel 3 is communicated below the sample inlet 1, and a filter sieve 2 is arranged at an inlet of the spiral flow channel 3. As shown in figure 2, the sample liquid is pushed by the syringe pump to be injected into the inlet of the spiral flow channel 3 from the sample inlet 1, and when the sample liquid flows through the filter sieve 2, large-particle impurities are captured, so that the flow channel of the device is prevented from being blocked. In this embodiment, the filter sieve 2 is composed of a micro-column array, and each micro-column in the micro-column array is uniformly distributed with a certain distance. The cross section of the micro-column is any one or combination of a circle, a triangle and an 'I' shape. Due to the structural design, impurities larger than the corresponding size can be captured when flowing through, and the risk of blocking a flow channel is reduced. In order to focus the cell particles in the spiral flow channel 3, the section height of the spiral flow channel 3 and the cell diameter satisfy 0.07<ap/h<0.3 wherein apThe particle diameter and h are the height of the spiral flow channel 3. Meanwhile, the vertical cross-sectional shape of the spiral flow channel 3 should be designed to be rectangular with a low aspect ratio (the aspect ratio AR is h/w)<1) Preferably, the ratio of the height to the width is 1/2-1/4, so that the cells passing through the spiral flow channel 3 can be sorted along the width direction of the flow channel; the cross section of the spiral flow channel 3 can also be designed into a trapezoid with different heights at two sides. The outlet of the spiral flow channel 3 is a Y-shaped double outlet 4, and the Y-shaped double outlet 4 is respectively communicated with the focusing module and the blood cell outlet 5. After the sample liquid enters the spiral flow channel 3, under the combined action of inertia force and dean drag force, circulating tumor cells and white blood cells with similar sizes in the sample liquid are close to the inner wall surface 11 of the flow channel, most blood cells are close to the outer wall surface 12, when the circulating tumor cells and the white blood cells with similar sizes reach the Y-shaped double outlets 4, the circulating tumor cells and the white blood cells with similar sizes flow into the focusing module, and most blood cells flow from the 5 portsAnd (6) discharging the device.
The focusing module comprises a focusing
the electric detection module is provided with a broadband impedance measurement system comprising a pair of ITO electrodes 8, a current amplifier, a data acquisition card and a computer, and the system comprises the application of a pseudorandom M sequence excitation signal on hardware, the sampling of a response signal and the analysis and extraction of a broadband impedance signal on software. The ITO electrode 8 is close to the outlet of the sudden expansion structure 7, and shielding electrodes are arranged around the ITO electrode 8 and used for reducing the interference of the external environment on the measurement electric signal. After the cells come out of the sudden expansion structure 7, the cells flow through the flow channel provided with the ITO electrode 8, the electric signals of the electrode are changed and amplified, collected and processed by a corresponding device, the broadband impedance of the cells is measured by applying a pseudorandom M sequence signal to the ITO electrode 8 below the flow channel, and then the cells flow into the deformation module.
The deformation module comprises a narrow structure 9 and a T-shaped flow channel double-outlet 10, wherein the narrow structure 9 and the flow channel wall form an included angle of 30-60 degrees, and then the narrow structure and the flow channel wall are straightly extended and narrowed to a required width, and the narrowing ratio is 0.4-0.6. The center of the T-shaped flow channel area of the double T-shaped flow channel outlets 10 is an area where the cells impact the wall surface to generate deformation. The inlet of the double outlet 10 of the T-shaped flow channel is provided with a narrowing structure 9, and cells pass through the narrowing structure 9 to better impact the cells on the center of the wall surface. The cells impact the wall surface of the T-shaped flow channel area of the double outlets 10 of the T-shaped flow channel after passing through the narrow structure 9, and the impact area is placed under a high-speed camera (300000fps) to capture deformation images and transmit the deformation images to a computer for processing and analysis; the image of the cell after impacting the wall surface is changed from the original circle to an ellipse, and the deformation capability of the cell is identified by analyzing the ratio b/a of the major axis and the minor axis after the cell is deformed and the initial diameter D of the cell. Finally, the cells flow out from the T-shaped flow channel double outlet 10.
The preparation material of each flow channel is Polydimethylsiloxane (PDMS), and can also be made of materials with good optical performance, such as glass, epoxy resin, polymethyl methacrylate (PMMA), Polycarbonate (PC) and the like. The prototype device is prepared by a soft lithography processing technology, and specifically comprises the steps of photoetching an SU-8 male mold, PDMS pouring, PDMS-glass bonding and packaging and the like. And packaging the PDMS micro-channel and the ITO micro-electrode by using a vacuum oxygen plasma bonding technology. In addition, the preparation of the male die can also be realized by the aid of the technologies of silicon wet method/deep reactive ion etching, ultra-precision machining, metal electroplating, photosensitive circuit board etching and the like.
As shown in fig. 3, after the particle suspension is injected into the spiral flow channel 3 through the sample inlet 1 at a specific flow rate, the fluid near the center line in the curved flow channel has a higher flow rate than the fluid near the wall surface, and flows outwards under the action of unbalanced centrifugal force and radial pressure gradient; at the same time, due to the conservation of mass in the closed flow channel, the fluid near the outer wall 12 will flow back along the upper and lower walls of the spiral flow channel 3, thus generating two vortices with opposite rotation directions in the direction perpendicular to the main flow direction, called dean flow or secondary flow. In addition, because the flow velocity of the fluid in the flow channel is distributed in a parabolic manner from the center of the fluid to the wall surface of the flow channel, the formed velocity gradient induces and generates a shear induced lift force pointing to the wall surface of the flow channel, so that the particles in the shear induced lift force move to the wall surface of the flow channel, and simultaneously, the wall surface and the fluid act together to generate a wall surface induced lift force driving the particles to leave the wall surface, and the resultant force of the two lift forces is called as an inertial lift force FL. At inertial lift force FLAnd dean drag force F induced by dean flowDUnder the combined action of the two components, the particles reach stable equilibrium positions a and b and do notParticles of the same size have different equilibrium positions.
As shown in fig. 4, an M-sequence digital signal (single cycle) is generated in a computer based on a MATLAB program, and the digital signal is converted into a voltage signal by using a USB data acquisition card in combination with a LabView data acquisition program and then applied to one end of the ITO electrode 8 repeatedly. After the response ion current signal obtained at the other end of the ITO electrode 8 is amplified and converted into a voltage signal by a current amplifier, the same data acquisition card is adopted for synchronous sampling and is stored as a TXT text file. Writing an MATLAB program in a computer to read a text file, decomposing acquired digital signals by taking the period of an M sequence as a unit, and sequentially carrying out quick M sequence conversion, pulse signal truncation and quick Fourier conversion on response signals in each period to obtain cell broadband impedance signals.
As shown in FIG. 5, after passing through the constriction 9, the cells collide against the wall of the flow channel from the center of the outlet; when the cell does not collide with the wall surface of the flow channel, the whole cell image shot by the high-speed camera is circular, and when the cell collides with the wall surface of the flow channel, the cell begins to deform until the cell deforms to the maximum; at this time, the cell image captured by the high-speed camera is elliptical. Thereafter, the cells are rebounded from the wall surface and finally flow out of the T-shaped flow channel double outlet 10. The high-speed camera transmits the image back to the computer and then processes the image by a pre-programmed program to analyze the size relationship before and after cell deformation.
As shown in FIG. 6, the cell shape changed from spherical to ellipsoidal by striking the wall surface with a flow rate of 90. mu.l/min and a significant deformation;
as shown in FIG. 7, under the AC signal, the impedance spectrum of the white blood cells and the circulating tumor cells is shown in the figure at the frequency of 1M.
The embodiment can show that the invention realizes the simultaneous detection of double parameters of cells by integrating cell deformation detection and cell impedance detection, greatly reduces the experiment and detection time and simultaneously determines the cell characteristics more accurately; at the same time, the series connection of the spiral sorting modules further reduces the operation time. In addition, the cell impacts the wall surface to generate deformation, so that the cell is stressed more and is easier to denature; the deformation mode also greatly improves the detection flux, and has larger detection flux and more obvious cell deformation compared with deformation modes such as dielectrophoresis induced deformation, atomic force microscopic deformation, microtubule sucking and the like.