CN111735854A - Multi-mode accurately-focused electrical impedance flow cytometry detection device and preparation method thereof - Google Patents
Multi-mode accurately-focused electrical impedance flow cytometry detection device and preparation method thereof Download PDFInfo
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- CN111735854A CN111735854A CN202010558863.6A CN202010558863A CN111735854A CN 111735854 A CN111735854 A CN 111735854A CN 202010558863 A CN202010558863 A CN 202010558863A CN 111735854 A CN111735854 A CN 111735854A
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- G01—MEASURING; TESTING
- 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
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/06—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a liquid
- G01N27/07—Construction of measuring vessels; Electrodes therefor
Abstract
The invention discloses a multimode accurate focusing electrical impedance flow cytometry detection device and a preparation method thereof, wherein the device comprises a non-conducting main body, a fluid dynamics focusing flow channel, an ultrasonic focusing flow channel, an electrical impedance detection flow channel and an outlet flow channel are sequentially arranged in the main body from a fluid inlet to the outlet direction, the fluid dynamics focusing flow channel comprises a middle sample flow channel and a sheath flow channel wrapped outside the sample flow channel, the sample flow channel is communicated with the sample inlet, the sheath flow channel is communicated with the sheath flow inlet through the sheath flow inlet flow channel, a piezoelectric element is arranged on the outer side of the ultrasonic focusing flow channel, electrical impedance detection electrodes are arranged at two ends of the electrical impedance detection flow channel, and the preparation method adopts double-nozzle 3D printing. The invention solves the problem of silting of a sample particle blocking point, realizes the aims of high focusing speed and accurate focusing position, effectively focuses cells quickly and accurately, and reduces the difficulty of signal processing.
Description
Technical Field
The invention relates to a microfluidic detection device, in particular to a multi-mode accurately-focused electrical impedance flow cytometry detection device and a preparation method thereof.
Background
Microfluidic devices, also commonly referred to as microfluidic chips, are mainly used in the fields of chemical analysis, biomedicine, environmental monitoring, and the like. Combined with flow cytometry, it is often used to detect microparticles of cells, genetic material, proteins, etc. In performing the detection, the sample particles in the micro flow channel should be stably focused at the central position to improve the detection accuracy. The focusing mode mainly comprises methods of hydrodynamic focusing, acoustic focusing and the like, and the detection mode mainly comprises methods of electrical impedance detection, fluorescence detection, light scattering, microscopic imaging and the like.
The hydrodynamic focusing mode applies a large focusing force to the cells, the focusing speed is high, but the focusing position is not accurate. The key of the focusing method lies in the structure of the micro-channel, if unidirectional focusing is adopted, the sample flow can only be formed into a line or a row, the final purpose of focusing can not be achieved, and although the effect is better when the cross section of the micro-channel is focused transversely and longitudinally, the complexity of the structure of the micro-channel is increased to a certain extent. The acoustic focusing requires more acoustic field energy to achieve better focusing, which results in greater energy density, creating ultrasonic cavitation that can potentially damage fragile biological particles. To avoid this, the acoustic focusing channel must be lengthened, which makes the device larger in size and inconvenient to manufacture and use. Electrical impedance measurements are typically made by pressing or gluing the device to the body, which complicates the manufacture of the device and also disrupts the integrity of the device, adversely affecting the performance of the device.
The fabrication of the micro-channel is supported by mature technologies such as lithography and etching, and the soft lithography technology is mainly used for the integral fabrication at present, but the process steps are complex, a large amount of professional manual operation is required, a dust-free operation environment and professional equipment are also required, so that the integral cost of the device is high, the fabrication period is prolonged, the batch production is difficult, and the application range of the micro-fluidic device is greatly limited.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to provide a multi-mode accurately-focused electrical impedance flow cytometry detection device and a preparation method thereof, which solve the problems of single detection mode, inaccurate focusing position and silted sample particle blocking points in the prior art.
The technical scheme is as follows: the invention relates to a multi-mode accurately focused electrical impedance flow cytometry detection device which comprises a non-conductive main body, wherein a fluid dynamics focusing flow channel, an ultrasonic focusing flow channel, an electrical impedance detection flow channel and an outlet flow channel are sequentially arranged in the main body from a fluid inlet to the fluid outlet, the fluid dynamics focusing flow channel comprises a middle sample flow channel and a sheath flow channel wrapped outside the sample flow channel, the sample flow channel is communicated with the sample inlet, the sheath flow channel is communicated with the sheath fluid inlet through a sheath flow inlet flow channel, a piezoelectric element is arranged on the outer side of the ultrasonic focusing flow channel, and electrical impedance detection electrodes are arranged at two ends of the electrical impedance detection flow channel.
In order to facilitate the installation and power supply of the piezoelectric element, a cavity is arranged in the main body corresponding to the ultrasonic focusing flow channel, an ultrasonic focusing body is arranged in the cavity, the ultrasonic focusing flow channel is arranged in the ultrasonic focusing body, and the piezoelectric element is arranged outside the ultrasonic focusing body. The piezoelectric element is matched with the outer wall of the ultrasonic focusing body, and the cross section of the outer wall of the ultrasonic focusing body is rectangular or circular.
For can link to each other with signal input and output device well, effectively reduce the actual operation degree of difficulty, electrical impedance detects the electrode and includes the cylinder main part, cylinder main part one end through semi-circular ring portion with the both ends runner intercommunication of electrical impedance detects the runner, the other end stretches out outside the non-conductive main part.
In order to ensure the effect of hydrodynamic focusing, improve the signal-to-noise ratio and facilitate the processing of signals, the inner diameter of a sample outlet of the sample flow channel is equal to the inner diameter of the electrical impedance detection flow channel, and the inner diameter of the sample outlet is half of the inner diameter of the ultrasonic focusing flow channel.
The preparation method of the multi-mode accurately-focused electrical impedance flow cytometry detection device adopts a double-nozzle 3D printer, and the electrical impedance detection electrode and other parts are printed out at one time by using conductive and non-conductive materials.
Has the advantages that: the invention adopts a multi-mode precision focusing method combining hydrodynamic focusing and ultrasonic focusing on a focusing mode, effectively solves the problems that the detection precision is obviously reduced and the ultrasonic focusing has potential destructiveness to fragile biological particles because a sample can deviate from a central position and easily stagnates at a blocking point in hydrodynamic focusing, and the hydrodynamic focusing is mainly used for providing focusing energy; ultrasonic focusing is mainly used to solve the problem of fouling of sample particle clogging points, thereby avoiding the use of high-energy ultrasonic waves and protecting fragile cell samples. The two are complementary, the advantages of large focusing force, high focusing speed and accurate ultrasonic focusing position applied to the cells by hydrodynamic focusing are exerted, the problems of inaccurate focusing during hydrodynamic focusing and small focusing force during ultrasonic focusing are weakened, the target of high focusing speed and accurate focusing position is realized, the cells are quickly and accurately effectively focused, and the difficulty of signal processing is reduced.
Drawings
FIG. 1 is a schematic view of the overall structure of the present invention;
FIG. 2 is a schematic diagram of a structure employing an annular piezoelectric element according to the present invention;
FIG. 3 is a schematic view of the invention in sections;
FIG. 4 is a schematic view of a hydrodynamic focal zone configuration;
FIG. 5 is a schematic view of an ultrasonic focusing region structure using a square piezoelectric element;
FIG. 6 is a schematic view of an ultrasonic focusing region structure using a ring-shaped piezoelectric element;
FIG. 7 is a schematic diagram of an electrical impedance detection zone configuration;
FIG. 8 is a schematic view of the outlet zone structure;
FIG. 9 is a schematic diagram of an electrical impedance detection electrode structure.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
As shown in fig. 1-9, the multi-mode accurately focused electrical impedance flow cytometry detection apparatus includes a non-conductive main body, a hydrodynamic focusing flow channel 13, an ultrasonic focusing flow channel 14, an electrical impedance detection flow channel 15 and an outlet flow channel 16 are sequentially arranged in the main body from a fluid inlet to an outlet, the hydrodynamic focusing flow channel 13 includes a middle sample flow channel 11 and a sheath flow channel wrapped outside the sample flow channel, an included angle between the sheath flow inlet flow channel 12 and the hydrodynamic focusing flow channel 13 is 90 °, the sample flow channel 11 is communicated with a sample inlet 41, the sheath flow channel is communicated with a sheath flow inlet 42 through the sheath flow inlet flow channel 12, a cavity is arranged in the main body corresponding to the position of the ultrasonic focusing flow channel, an ultrasonic focusing body is arranged in the cavity, the ultrasonic focusing flow channel is arranged in the ultrasonic focusing body 17, a piezoelectric element is adhered on the outer wall of the ultrasonic focusing body, the cross section of the outer wall of the ultrasonic focusing flow channel 14 can be rectangular or circular, four rectangular piezoelectric elements 51 and one annular piezoelectric element 61 are correspondingly and respectively used, the inlet of the electrical impedance detection flow channel 15 is communicated with the outlet of the ultrasonic focusing flow channel 14, the inner diameter of the electrical impedance detection flow channel is smaller than the inner diameter of the ultrasonic focusing flow channel 14, two ends of the electrical impedance detection flow channel 15, which are respectively connected with the ultrasonic focusing flow channel 14 and the outlet flow channel, are respectively provided with an electrical impedance detection electrode 71, the electrical impedance detection electrode 71 comprises a cylindrical main body, one end of the cylindrical main body is communicated with the flow channels at two ends of the electrical impedance detection flow channel 15 through a semicircular ring part, the other end extends out of the non-conductive main body, the inner diameter of the outlet flow channel is the same as the inner diameter of the ultrasonic focusing flow channel 14, the inlet of the cylindrical, the size of the cross section of the outer wall of the device is obviously smaller than the width and height of the main body, so that the piezoelectric element is convenient to mount and supply power, four quarter cylinders adopted at four corners of the cavity are connected with the main body, the integral strength of the device can be ensured, an ultrasonic focusing part is protected, the inner diameters of an inlet and an outlet are properly enlarged so that the connection between a micro-channel and an external device can be facilitated, two electrical impedance detection electrodes extending out of a cuboid region of the device can be well connected with a signal input and output device, and the actual operation difficulty is effectively reduced. The inner diameter of the sample outlet 43 of the sample flow channel 11 is equal to the inner diameter of the electrical impedance detection flow channel 15, and the inner diameter of the sample outlet 43 is half of the inner diameter of the ultrasonic focusing flow channel 14, so that the arrangement can ensure the hydrodynamic focusing effect, improve the signal-to-noise ratio, facilitate the signal processing,
the invention is manufactured by one-step molding by using a 3D printing method, non-conductive resin is used as a main body material, conductive composite resin is used as an electrical impedance detection electrode material, and the manufacturing is finished by using a double-nozzle 3D printer after the drawing of the structure is finished by using CAD.
When the invention is used, the required liquid is pumped into the micro-channel of the chip by a pressure pump through the conduit, the conduit is respectively inserted into the sample inlet 41 and the sheath liquid inlet 42, the conduit is also inserted into the outlet channel 81, and the other side of the conduit is connected with the waste liquid collecting device. Flowing the sample solution that has been pretreated into the sample flow channel 11 through the conduit and the sample inlet 41; the prepared protective liquid enters the sheath liquid inlet flow channel 12 through the catheter and the sheath liquid inlet 42, a simple harmonic signal with the same frequency and amplitude and constant amplitude is input to each piezoelectric element, one of the two electrical impedance detection electrodes is connected to a signal processing device comprising a signal amplifier, a computer and the like, and the other one is connected to a signal generator.
When the sample flows to the sample outlet 43, the sheath fluid will squeeze the sample flow from the periphery through the hydrodynamic focusing channel 13, so that the sample particles are primarily focused at the center of the micro channel, and the two are converged and enter the ultrasonic focusing channel 14, where the acoustic resistance generated by the piezoelectric element focuses the off-center sample particles at the center of the micro channel, and the sample particles are prevented from being deposited.
After the precisely focused stream flows to the electrical impedance detection flow channel inlet 72 and into the electrical impedance detection flow channel 15, since the sample cell particles can be considered as non-conductive particles, which causes the resistance between the two electrical impedance detection electrodes to increase proportionally with the discharge of the cells from the liquid in the space, thereby causing the amplitude of the input unit pulse signal to decrease in a pulse-like manner, by virtue of the precise pre-focusing, the cells are believed to pass through the electrical impedance detection flow path one after the other, with each pulse representing the passage of a sample cell particle, the signal will be amplified by the amplification circuit and then recorded in the computer and the focused stream flowing through the electrical impedance detection flow path will enter the exit flow path 16 through the exit flow path inlet 73 and will eventually be discharged through the exit flow path outlet 81 and the conduit into a waste collection device.
The ratio of the flow rates of the sheath fluid flow and the focusing fluid flow can be changed by adjusting the pressures of the two pressure pumps, or the frequency and the amplitude of a simple harmonic signal input into the piezoelectric material are changed, and finally the focusing effect and the detection accuracy are changed until an output signal which can meet the processing requirement is obtained.
Claims (6)
1. The multi-mode accurately focused electrical impedance flow cytometry detection device is characterized by comprising a non-conductive main body, wherein a hydrodynamic focusing flow channel (13), an ultrasonic focusing flow channel (14), an electrical impedance detection flow channel (15) and an outlet flow channel (16) are sequentially arranged in the main body from a fluid inlet to an outlet, the hydrodynamic focusing flow channel (13) comprises a middle sample flow channel (11) and a sheath flow channel wrapped outside the sample flow channel, the sample flow channel (11) is communicated with a sample inlet (41), the sheath flow channel is communicated with a sheath liquid inlet (42) through a sheath liquid inlet flow channel (12), a piezoelectric element is arranged on the outer side of the ultrasonic focusing flow channel (14), and electrical impedance detection electrodes (71) are arranged at two ends of the electrical impedance detection flow channel (15).
2. The multi-mode precisely focused electrical impedance flow cytometry apparatus of claim 1 wherein a cavity is disposed in the body corresponding to the position of the ultrasonic focusing flow channel (14), an ultrasonic focusing body (17) is disposed in the cavity, the ultrasonic focusing flow channel (14) is disposed in the ultrasonic focusing body (17), and the piezoelectric element is disposed outside the ultrasonic focusing body (17).
3. The multi-mode precisely focused electrical impedance flow cytometry apparatus of claim 2 wherein the piezoelectric element is fitted to the outer wall of the ultrasonic focusing body (17), the outer wall of the ultrasonic focusing body (17) being rectangular or circular in cross-section.
4. The multi-mode precisely focused electrical impedance flow cytometry apparatus of claim 1, wherein the electrical impedance detection electrode (71) comprises a cylindrical body, one end of the cylindrical body is communicated with the two end channels of the electrical impedance detection channel (15) through a semicircular ring part, and the other end of the cylindrical body extends out of the non-conductive body.
5. The multi-mode precisely focused electrical impedance flow cytometry apparatus of claim 1 wherein the sample outlet (43) inner diameter of the sample flow channel (11) and the electrical impedance detection flow channel (15) inner diameter are equal, and the sample outlet (43) inner diameter is half of the ultrasonic focusing flow channel (14) inner diameter.
6. A method for preparing a multi-mode accurately focused electrical impedance flow cytometry device as described in claim 1, wherein the electrical impedance detection electrodes and other parts are printed out at one time by using conductive and non-conductive materials by using a dual-nozzle 3D printer.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114295688A (en) * | 2021-12-30 | 2022-04-08 | 北京航空航天大学 | Electrical impedance tomography sensor suitable for microchannel heterogeneous object detection |
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