CN106644900B - Impedance pulse particle counting device based on non-uniform electric field and counting method thereof - Google Patents
Impedance pulse particle counting device based on non-uniform electric field and counting method thereof Download PDFInfo
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- 238000001514 detection method Methods 0.000 claims abstract description 122
- 239000007788 liquid Substances 0.000 claims abstract description 72
- 238000002347 injection Methods 0.000 claims abstract description 45
- 239000007924 injection Substances 0.000 claims abstract description 45
- 239000004205 dimethyl polysiloxane Substances 0.000 claims abstract description 9
- 235000013870 dimethyl polysiloxane Nutrition 0.000 claims abstract description 9
- CXQXSVUQTKDNFP-UHFFFAOYSA-N octamethyltrisiloxane Chemical compound C[Si](C)(C)O[Si](C)(C)O[Si](C)(C)C CXQXSVUQTKDNFP-UHFFFAOYSA-N 0.000 claims abstract description 9
- 238000004987 plasma desorption mass spectroscopy Methods 0.000 claims abstract description 9
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 claims abstract description 9
- 239000011521 glass Substances 0.000 claims abstract description 8
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 26
- 229910052697 platinum Inorganic materials 0.000 claims description 13
- 230000008569 process Effects 0.000 claims description 13
- SNRUBQQJIBEYMU-UHFFFAOYSA-N dodecane Chemical compound CCCCCCCCCCCC SNRUBQQJIBEYMU-UHFFFAOYSA-N 0.000 claims description 12
- 239000000243 solution Substances 0.000 claims description 11
- 238000004458 analytical method Methods 0.000 claims description 7
- 230000003321 amplification Effects 0.000 claims description 6
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 6
- 238000005370 electroosmosis Methods 0.000 claims description 4
- 230000009471 action Effects 0.000 claims description 3
- 239000007853 buffer solution Substances 0.000 claims description 3
- 238000005538 encapsulation Methods 0.000 claims description 2
- 239000002923 metal particle Substances 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 241000894006 Bacteria Species 0.000 description 2
- 239000004793 Polystyrene Substances 0.000 description 2
- 241000700605 Viruses Species 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
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- 230000003287 optical effect Effects 0.000 description 2
- 229920002223 polystyrene Polymers 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
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- 230000007613 environmental effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000001499 laser induced fluorescence spectroscopy Methods 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920002120 photoresistant polymer Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000005180 public health Effects 0.000 description 1
- 238000011897 real-time detection Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/1031—Investigating individual particles by measuring electrical or magnetic effects
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/1023—Microstructural devices for non-optical measurement
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N2015/1024—Counting particles by non-optical means
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Abstract
The invention discloses an impedance pulse particle counting device and a counting method based on a non-uniform electric field. The device comprises a glass negative film, a PDMS micro-fluidic chip, a signal amplifying element and a signal acquisition control system, wherein the PDMS micro-fluidic chip is notched with a micro-channel, and the micro-channel comprises: the two ends are respectively provided with a main channel of an oil inlet liquid storage hole and an oil outlet liquid storage hole; a sample injection channel extending from the middle position of the main channel to a direction far away from the main channel, wherein the tail end of the sample injection channel is provided with a sample injection channel liquid storage hole; and a detection channel extending from a position which is a certain distance away from the intersection of the main channel and the sample injection channel to a direction away from the main channel, wherein the ratio of the width of the detection channel to the width of the main channel is fixed, and the tail end of the detection channel is provided with a detection channel liquid storage hole. The invention has simple structure and high detection precision, and can realize detection and counting without particles entering and exiting the detection area.
Description
Technical Field
The invention relates to the technical field of particle detection, in particular to an impedance pulse particle counting device based on a non-uniform electric field and a counting method thereof.
Background
Accurately counting particles in a sample has important significance and needs in a number of fields; for example, in the fields of biomedical research, public health detection, marine environmental monitoring, etc., there is an urgent need to investigate portable rapid particle counting devices or methods for determining the number of targets (e.g., bacteria, viruses, marine microorganisms, etc.).
Currently available methods for particle counting include the following:
1) Photoresistance method (optical interference principle): the photoresist method is the most widely used particle counting method at present, also called a light obstruction method or a light shielding method, and is a method for detecting particle size of particles by utilizing light intensity variation caused by shielding of light by the particles. The method has simple principle, but needs a photoelectric conversion system with relatively high cost and complex structure, and has low detection precision;
2) Inductance method: the inductance method utilizes the phenomenon that the inductance of the micropores is changed when particles pass through the detection micropores to monitor the change of the inductance signal of the detection micropores, so that the particle count can be realized. The method is simple in principle, can detect various metal particles, but is only applicable to the metal particles, and the detection accuracy is limited;
3) Capacitance method: the capacitance method is a non-contact detection method, when particles pass through detection micropores, the capacitance of the micropores can be changed, and particle counting can be realized by monitoring the change of capacitance signals of the micropores. The method can be used for counting particles in low-conductivity solution (such as oil liquid), and the capacitance detection object is mainly metal particles, but the detection of the tiny capacitance depends on a high-precision detection instrument, so that the portability development of the method is limited.
4) Laser induced fluorescence detection method: the particles are self-fluorescent after laser irradiation, can be detected by a photoelectric sensor and realize particle counting. The method is particularly suitable for the related fields of blood analysis, immunology and microbiology, has accurate counting and convenient detection, but the sample must be treated before detection, the optical element used for detection has high cost and complex structure, and extremely tiny particles cannot be detected;
5) Resistance pulse method (RPS): the resistance pulse method is based on that when particles flow through micropores with an electric field, voltage changes at two ends of the micropores generate detection signals, so that detection is realized; the method is simple and convenient to operate, and is the particle counting method with highest precision at present.
The microfluidic chip device can integrate basic operations such as sample preparation, reaction, separation, detection and the like in biological, chemical and medical analysis processes onto a micron-scale chip, and automatically complete the whole analysis process. The method has the characteristics of controllable liquid flow, extremely few consumed reagents and samples, ten times or hundreds times higher analysis speed and the like, can simultaneously analyze hundreds of samples in a period of minutes or even shorter, and can realize the whole pretreatment and analysis processes of the samples on line.
With the rapid development of microfluidic chip processing technology in recent years, many researches for counting micro-nano particles, cells, bacteria, viruses and the like on a microfluidic chip by using an RPS method have been reported. For example, a typical microfluidic RPS counting chip is to process a detection channel with a line width slightly larger than that of particles to be detected in the middle of a main channel with a width of hundreds of micrometers, and then apply a dc electric field at two ends of the main channel; when the insulating particles in the solution pass through the detection channel, the voltage of two ends of the insulating particles is changed, a pulse signal is obtained by adopting a proper signal acquisition system, and the number of the pulse signals is the number of the particles. In order to conveniently acquire the voltage changes at two sides of the detection channel, different chip structures are invented.
The original detection chip structure only comprises a main channel with a width of hundreds of micrometers and a detection channel with a line width slightly larger than that of particles to be detected, wherein the detection channel is arranged in the middle of the main channel; the detection chip in the later establishes a detection arm channel before and after the detection channel, directly measures voltage signals at two ends of the channel by using an electrode, and improves the detection signal-to-noise ratio by differential amplification, thereby improving the detection precision; the latest counting chip adopts a structure with public liquid inlet holes distributed annularly in multiple channels, each channel comprises a main channel, a detection channel, a liquid storage hole and the like, the liquid inlet holes of the counting chip are connected with a power anode, the liquid storage holes are connected with a power cathode after being connected with resistors in series, the channels are used as references, the current counting chip can well eliminate system noise, and the counting chip can sequentially work by controlling the channels to realize high-flux counting. However, it should be noted that in order to obtain a higher detection signal-to-noise ratio, the current counting chip often needs to make the size of the detection channel and the size of the particle similar, and the corresponding detection of the nanoparticle also needs to process the detection channel with a nano size, which requires very complex processing steps and expensive processing equipment.
In addition, because the size of the detection channel is relatively close to that of the particles, the particles are easy to block the detection channel; meanwhile, impurities in the solution can cause partial or even complete blockage of a detection channel, so that an error or detection interruption occurs in the particle size detection result of the particles, and the accuracy and stable operation of the system are affected.
Disclosure of Invention
In view of the defects existing in the prior art, the invention aims to provide the impedance pulse particle counting device based on the non-uniform electric field, wherein particles to be detected enter a main channel from a sample channel in the detection process and then flow through the junction of the main channel and the sample channel, namely, the particles do not enter a detection channel, so that the detection precision and the channel blocking resistance are effectively improved.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
the utility model provides an impedance pulse particle counting assembly based on inhomogeneous electric field, its includes glass film, PDMS micro-fluidic chip, signal amplification element and signal acquisition control system, the one side that the PDMS micro-fluidic chip is notched has the microchannel with glass film encapsulation is as an organic whole to form the microchannel that supplies the sample to await measuring to circulate, its characterized in that, the microchannel includes:
the two ends are respectively provided with a main channel of an oil inlet liquid storage hole and an oil outlet liquid storage hole;
a sample injection channel extending from the middle position of the main channel to a direction far away from the main channel, wherein the tail end of the sample injection channel is provided with a sample injection channel liquid storage hole;
the detection channel extends from a position which is a certain distance away from the intersection of the main channel and the sample injection channel to a direction away from the main channel, the ratio of the width of the detection channel to the width of the main channel is fixed, and the tail end of the detection channel is provided with a detection channel liquid storage hole;
meanwhile, the platinum electrodes are inserted into the liquid storage hole of the sample injection channel and the liquid storage hole of the detection channel, the platinum electrodes in the liquid storage hole of the sample injection channel are connected with the positive electrode of the direct current power supply through a reference resistor, and the platinum electrodes in the liquid storage hole of the detection channel are connected with the negative electrode of the direct current power supply; the two ends of the reference resistor are connected with the input end of the signal amplifying element through wires, and the output end of the signal amplifying element is connected with the signal acquisition control system.
Further, as a preferred aspect of the present invention:
the detection channel is at an angle to the main channel, and the ratio of the width of the detection channel to the width of the main channel is preferably 1/200.
Further, as a preferred aspect of the present invention:
the signal amplifying element adopts a differential amplifier element.
Further, as a preferred aspect of the present invention:
the signal acquisition control system comprises an NI acquisition card and a computer.
Another object of the present invention is to provide a method for counting particles based on the above particle counting device, which is characterized by comprising the following steps:
1) Dropwise adding a sample: firstly, dropwise adding a certain amount of PBS buffer solution into a liquid storage hole of the sample injection channel and a liquid storage hole of the detection channel, dropwise adding a certain amount of dodecane into an oil inlet liquid storage hole of the main channel, and then dropwise adding a certain amount of sample to be detected into the liquid storage hole of the sample injection channel;
2) Sample transport: the direct current power supply is connected, so that a sample to be detected in the liquid storage hole of the sample injection channel is conveyed to the main channel under the action of electroosmosis and pressure, and then flows to the oil outlet liquid storage hole of the main channel under the driving of the pressure difference of the main channel;
3) Signal amplification acquisition and analysis: the method comprises the steps that voltage pulse signals at two ends of a reference resistor are collected through platinum electrodes in a liquid storage hole of a detection channel and a liquid storage hole of a sample injection channel, the collected signals are amplified through a differential amplifier connected with the reference resistor, and then the signals are recorded and corresponding detection data are displayed through a signal collection control system, namely the number of sample particles is detected; the number detection value of the particles is equal to the number of the pulse signals of the detection channel.
Dodecane is used in the detection process to focus the particle solution to flow through the junction of the main channel and the detection channel.
Compared with the prior art, the invention has the beneficial effects that:
1) When the invention is used for detection, the particles of the sample to be detected do not enter the detection channel, so that the phenomenon of channel blockage is avoided, and the detection stability is high;
2) The invention continuously improves the signal to noise ratio of the detection signal by increasing the ratio of the main channel to the detection channel, thereby improving the detection precision.
Drawings
FIG. 1 is a schematic diagram of a micro-fluidic chip of a counting device according to the present invention;
fig. 2 is a system configuration diagram of the present invention.
In the figure: m, a micro-fluidic chip, L, a glass negative film, A, a main channel oil inlet liquid storage hole, B, a main channel oil outlet liquid storage hole, C, a sample injection channel liquid storage hole, D, a detection channel liquid storage hole, 1, a main channel, 2, a sample injection channel, 3 and a detection channel.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
When particles flow through micropores with an electric field, the electric field is obviously disturbed, and voltage at two ends of the corresponding micropores is changed to generate a voltage pulse signal. Detecting the number of the voltage pulse signals can realize the detection of the number of the sample particles.
Based on the above design background, the invention designs an impedance pulse particle counting device based on a non-uniform electric field and a counting method thereof, and the following technical scheme is further described with reference to the drawings and the specific embodiments:
as shown in fig. 1, an impedance pulse particle counting device based on a non-uniform electric field comprises a glass negative L, PDMS micro-fluidic chip M, a signal amplifying element and a signal acquisition control system.
The PDMS microfluidic chip is notched with a side of the microchannel and the glass negative film are packaged into a whole to form a microchannel for the circulation of a sample to be tested, and is characterized in that the microchannel comprises: the two ends are respectively provided with a main channel of an oil inlet liquid storage hole and an oil outlet liquid storage hole; the sample injection channel extends from the middle position of the main channel to a direction far away from the main channel, a sample injection channel liquid storage hole is formed at the tail end of the sample injection channel, and the ratio of the width of the sample injection channel to the width of the main channel is fixed, preferably 1/10; and a detection channel extending from a position which is a certain distance away from the intersection of the main channel and the sample injection channel to a direction which forms a certain angle with the main channel, wherein the ratio of the width of the detection channel to the width of the main channel is preferably 1/200, and the tail end of the detection channel is provided with a liquid storage hole of the detection channel.
And the platinum electrodes are inserted into the liquid storage holes of the sample injection channel and the liquid storage holes of the detection channel. The platinum electrode in the liquid storage hole of the sample injection channel is connected with the positive electrode of the direct current power supply through a reference resistor, and the platinum electrode in the liquid storage hole of the detection channel is connected with the negative electrode of the direct current power supply so as to realize the electroosmosis transportation process of the sample to be detected flowing from the liquid storage hole of the sample injection channel into the main channel from the sample injection channel; after the sample flows into the main channel, the sample flows to the oil outlet liquid storage hole of the main channel under the drive of pressure difference;
both ends of the reference resistor are connected with the input end of the signal amplifying element through wires. Preferably, the signal amplifying element is a differential amplifier element.
The output end of the signal amplifying element is connected with the signal acquisition control system and is used for realizing the amplifying, acquisition and detection process of the number signals of the sample particles to be detected in the detection channel. Preferably, the signal acquisition control system comprises an NI acquisition card and a computer.
The following test is performed using polystyrene sample particles as an example, as shown in FIG. 2:
device parameters of this embodiment: the chip detection channel used in this embodiment has a size of 1*5 μm (width×height), the distance from each liquid storage hole to the middle of the main channel of the chip is 5cm, the main micro channel has a size of 200×5 μm (width×height), and the sample injection channel has a size of 20×5 μm (width×height); the sample to be detected is a 3 mu m polystyrene particle solution; the buffer was PBS (1×) solution; the voltage applied to the liquid storage hole of the sample injection channel and the liquid storage hole of the detection channel is 48V;
the device comprises a main channel oil inlet liquid storage hole A, a main channel oil outlet liquid storage hole B, a sample injection channel liquid storage hole C, a detection channel liquid storage hole D, a main channel 1, a sample injection channel 2 and a detection channel 3 which are positioned on the PDMS micro-fluidic chip. Platinum electrodes are inserted into the sample injection channel liquid storage hole C and the detection channel liquid storage hole D and are connected to two ends of a direct current power supply through a resistor R; two ends of the resistor R are connected in parallel with two input ends of a differential amplifier through two wires; the output end of the differential amplifier is connected to the input end of the NI data acquisition card; the NI output signal can be displayed and analyzed directly at the connected computer.
The method for counting particles based on the particle counting device comprises the following steps:
1) Dropwise adding a sample: firstly, dropwise adding a certain amount of PBS buffer solution into a liquid storage hole of a sample injection channel and a liquid storage hole of a detection channel, dropwise adding a certain amount of dodecane into an oil inlet hole of a main channel, ensuring that the oil pressure is always higher than the solution pressure, and then dropwise adding a certain amount of sample to be detected into a liquid inlet hole of a sample channel;
2) Sample transport: and (3) switching on a direct current power supply, conveying the sample in the liquid storage hole C of the sample injection channel to the main channel under the action of electroosmosis and pressure, driving the sample to flow to the oil outlet liquid storage hole B of the main channel under the pressure difference of the main channel, enabling particles to be detected to enter the main channel from the sample channel in the detection process, and enabling the particles to flow through the junction of the main channel and the sample channel, namely enabling the particles not to enter the detection channel. Because the oil is non-conductive, an electric field does not exist in the area where the oil is located in the channel, and therefore the distribution of the electric field can be limited by controlling the position of the oil-water interface. In practice, it is necessary to ensure that the distance from the oil-water interface at the junction of the main channel and the detection channel to the detection channel is only 2-3 times the particle size of the particles to be detected.
Since the electric field is applied only to the sample injection channel and the detection channel, and the width of the detection channel is very narrow, the electric field strength of the interface area between the detection channel and the main channel is very high (i.e. the electric lines of force are very dense). When particles pass through the junction area of the detection channel and the main channel, the electric field lines can be easily disturbed, so that the voltage of the detection channel is changed, the voltage at two ends of the resistor R is further changed, a detection signal is generated, the detection signal is amplified by the differential signal of the AD620 differential amplifier and then is input to the NI acquisition card, and the output signal of the NI acquisition card can be directly displayed on a connected computer and analyzed.
3) Signal amplification acquisition and analysis: the voltage pulse signals at two ends of the reference resistor are collected through the platinum electrodes in the liquid storage hole of the detection channel and the liquid storage hole of the sample injection channel, and after the collected signals are amplified through the differential amplifier connected with the reference resistor, the signal collection system records and displays corresponding detection data, namely the number of the sample particles is detected.
Detection result: the real-time detection result can be directly obtained through a computer, and the number of particles in the sample is equal to the number of pulse signals.
According to the impedance pulse particle counting device and the counting method based on the nonuniform electric field, in the detection process, dodecane is used for focusing particle solution to flow through the junction of the main channel and the detection channel, and particles to be detected enter the main channel from the sample channel and then flow through the junction of the main channel and the sample channel. Because the electric field intensity of the junction area of the detection channel and the main channel is very high, and particles do not enter the detection channel, the detection precision and the channel blocking resistance are effectively improved.
The foregoing is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art, who is within the scope of the present invention, should make equivalent substitutions or modifications according to the technical scheme of the present invention and the inventive concept thereof, and should be covered by the scope of the present invention.
Claims (4)
1. The utility model provides an impedance pulse particle counting assembly based on inhomogeneous electric field, its includes glass film, PDMS micro-fluidic chip, signal amplification element and signal acquisition control system, the one side that the PDMS micro-fluidic chip is notched has the microchannel with glass film encapsulation is as an organic whole to form the microchannel that supplies the sample to await measuring to circulate, its characterized in that, the microchannel includes:
the two ends are respectively provided with a main channel of an oil inlet liquid storage hole and an oil outlet liquid storage hole;
the sample injection channel extends from the middle position of the main channel to a direction away from the main channel, the ratio of the width of the sample injection channel to the width of the main channel is fixed, and the tail end of the sample injection channel is provided with a sample injection channel liquid storage hole;
the detection channel extends from a position which is a certain distance away from the intersection of the main channel and the sample injection channel to a direction away from the main channel, the ratio of the width of the detection channel to the width of the main channel is fixed, and the tail end of the detection channel is provided with a detection channel liquid storage hole;
meanwhile, platinum electrodes are inserted into the liquid storage hole of the sample injection channel and the liquid storage hole of the detection channel, the platinum electrodes in the liquid storage hole of the sample injection channel are connected with the positive electrode of the direct current power supply through a reference resistor, and the platinum electrodes in the liquid storage hole of the detection channel are connected with the negative electrode of the direct current power supply; the two ends of the reference resistor are connected with the input end of the signal amplifying element through wires, and the output end of the signal amplifying element is connected with the signal acquisition control system.
2. An impedance pulse particle counting apparatus based on a non-uniform electric field according to claim 1, wherein:
the detection channel forms a certain angle with the main channel, and the width ratio of the detection channel to the main channel is 1/200.
3. A method of particle counting in a non-uniform electric field based impedance pulse particle counting apparatus according to claim 1, comprising the steps of:
1) Dropwise adding a sample: firstly, dropwise adding a certain amount of PBS buffer solution into a liquid storage hole of the sample injection channel and a liquid storage hole of the detection channel, dropwise adding a certain amount of dodecane into an oil inlet liquid storage hole of the main channel, and then dropwise adding a certain amount of sample to be detected into the liquid storage hole of the sample injection channel;
2) Sample transport: the direct current power supply is connected, so that a sample to be detected in a liquid storage hole of the sample injection channel is conveyed to the main channel under the action of electroosmosis and pressure, then flows to an oil outlet liquid storage hole of the main channel under the drive of pressure difference of the main channel, particles to be detected enter the main channel from the sample channel in the detection process, and then flow through the junction of the main channel and the sample channel, namely the particles do not enter the detection channel;
3) Signal amplification acquisition and analysis: the method comprises the steps that voltage pulse signals at two ends of a reference resistor are collected through platinum electrodes in a liquid storage hole of a detection channel and a liquid storage hole of a sample injection channel, the collected signals are amplified through a signal amplifying element connected with the reference resistor, and then the signal collecting control system records and displays corresponding detection data, namely the number of sample particles is detected; the number detection value of the particles is equal to the number of the pulse signals of the detection channel.
4. A particle counting method according to claim 3, characterized in that:
dodecane is used in the detection process to focus the particle solution to flow through the junction of the main channel and the detection channel.
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| CN107462512B (en) * | 2017-08-18 | 2019-11-01 | 中国科学院电子学研究所 | Unicellular intrinsic electrology characteristic detection device and method |
| CN108279202B (en) * | 2018-03-28 | 2023-05-30 | 大连海事大学 | Particle counting device and method with adjustable detection precision |
| CN108458963B (en) * | 2018-04-13 | 2023-06-06 | 大连海事大学 | Microfluidic chip device and method for sequentially separating and counting particles and cells based on nano-micro channel combination |
| CN108226013B (en) * | 2018-04-13 | 2024-02-13 | 大连海事大学 | Device and method for improving particle detection precision and flux by electric field focusing |
| CN108627448A (en) * | 2018-06-05 | 2018-10-09 | 江苏卓微生物科技有限公司 | The method of counting micro particles |
| CN110553956B (en) * | 2019-09-27 | 2021-11-12 | 东莞东阳光医疗智能器件研发有限公司 | Impedance pulse particle detection device, detection system and detection method |
| CN112415058B (en) * | 2020-11-09 | 2021-12-14 | 华中农业大学 | Biosensing detection method based on microchannel resistance change caused by concentration change of insulating microspheres |
| CN112378827B (en) * | 2020-11-24 | 2024-04-26 | 大连海事大学 | Particle detection device with wide size range |
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