CN116399787A - Impedance flow cytometer based on organic semiconductor - Google Patents

Abstract

The invention provides an impedance flow cytometer based on an organic semiconductor, belonging to the technical field of impedance flow cytometry; the problems of low detection precision, low integration level and difficult miniaturization of the existing impedance flow cytometer are solved; the micro-fluidic system comprises a micro-fluidic device, a first signal generating circuit, a second signal generating circuit and a data reading circuit which are integrated on a PCB (printed circuit board), wherein the micro-fluidic device comprises a micro-fluidic channel and two organic electrochemical transistors, a focusing area electrode is arranged at a sample inlet of the micro-fluidic channel, and the first signal generating circuit and the second signal generating circuit are respectively connected to the upper end and the lower end of the focusing area electrode; the phase-locked amplifier generates an alternating current signal and transmits the alternating current signal to the focusing region electrode through the first signal generating circuit and the second signal generating circuit, and the data reading circuit realizes cell impedance measurement by reading drain currents of the two electromechanical chemistry transistors; the invention is applied to the impedance flow cytometer.

Description

An Impedance Flow Cytometer Based on Organic Semiconductors

technical field

The invention provides an organic semiconductor-based impedance flow cytometer, which belongs to the technical field of impedance flow cytometer.

Background technique

Compared to typical flow cytometer channel sizes, the miniaturized size allows microfluidic systems to analyze individual cells to identify cellular variability in gene expression, or drug response in a population of cells. OECT-based cytometers have lower size, lower cost, and are more portable than traditional benchtop instruments. In addition, impedance flow cytometry has significant advantages such as label-free, low contamination, and fast detection speed, which can greatly reduce time consumption and reduce manufacturing costs.

Flow cytometry is a technique for multi-parameter analysis, rapid and accurate quantitative analysis and sorting of biological particles and non-biological particles such as cells and subcellular structures suspended in liquid flow. Traditional flow cytometers usually use cell labeling methods to analyze them, but the fluorescent labeling of cells has a great probability of damaging the cell surface structure and reducing cell viability. The labeled cells are difficult to carry out subsequent follow-up due to damage. Biochemical analysis. Compared to traditional flow cytometry, impedance analysis offers the possibility to evaluate cell characteristics that cannot be achieved by common labeling methods. Like fluorescence spectroscopy, the impedance spectrum of cells can reveal the characteristics of cells. Therefore, multiparametric analysis can also be performed using impedance cytometry, a label-free approach that protects cells from adverse effects of label preparation.

Impedance flow cytometry is based on the detection of the dielectric properties of cells, and cell characterization by dielectric properties does not require immunolabeling. Cells have parameters such as membrane capacitance, membrane resistance, cell fluid resistance, nuclear capacitance, nuclear resistance, and conductivity. Dielectric properties such as membrane capacitance and conductivity reflect the shape and function of the membrane, and the shape and function of the membrane are related to the relationship between cells. Physiological differences between cells or pathological changes of cells over time. For example, when cells of different sizes and activities flow through a wide-frequency AC electric field with the suspension, different electrical impedance signals will be generated, and information such as cell concentration, number, activity, and size can be obtained after analysis. Compared with traditional flow cytometry, this impedance flow cytometer can reveal more comprehensive cell characteristics.

When field effect transistors are applied to impedance measurement, the excitation voltage U _G (ω) on the gate will generate two current responses, namely source-drain current ( I _D ) and gate-source current ( I _G ). Among them, the quotient _of U _G (ω) and I _G (ω) is equivalent to the two-electrode system impedance Z (ω), and the quotient of ID (ω) and U _G (ω) is the transconductance response of the field effect transistor ( g _m (ω)). Due to the amplification characteristics of transistors, mid and low frequency I _D (ω) is usually several orders of magnitude of I _G (ω). Therefore, the mutual compensation technology of low-frequency transconductance response and high-frequency gate impedance in transistors can solve the problem of surge interface impedance attenuation current frequency response in the process of electrode miniaturization.

Organic Electrochemical Transistor (OECT) is a kind of field-effect transistor, which is a kind of field-effect transistor with a conductive polymer capable of three-dimensional doping of ions as the semiconductor layer and an aqueous solution as the dielectric layer. Its steady-state transconductance value can reach hundreds of millisiemens, which can Efficiently transduce and amplify low-level ion fluxes in biological systems into electronic output signals. The signal amplification capability based on OECT is nearly a hundred times that of conventional organic transistors. Using OECT as the electrode of impedance flow cytometer will greatly improve the detection accuracy and promote the development of its integration and miniaturization.

Contents of the invention

In order to solve the problems of low detection accuracy, low integration level and difficult miniaturization of the existing impedance flow cytometer, the invention proposes an impedance flow cytometer based on organic semiconductors.

In order to solve the above technical problems, the technical solution adopted by the present invention is: an impedance flow cytometer based on organic semiconductors, including a microfluidic system, a lock-in amplifier, and a PC terminal. The microfluidic system includes A microfluidic device, a first signal generating circuit, a second signal generating circuit, and a data readout circuit, the microfluidic device includes a microfluidic channel for cells to enter the microfluidic system, at least two for measuring cell impedance An organic electrochemical transistor, the sample inlet of the microfluidic channel is provided with a focusing area electrode, and the first signal generating circuit and the second signal generating circuit are respectively connected to the upper and lower ends of the focusing area electrode to generate Dielectrophoretic force;

The AC signal generated by the lock-in amplifier is transmitted to the electrode of the focus area through the first signal generating circuit and the second signal generating circuit, and the data readout circuit realizes differential measurement of cell impedance by reading out the drain current of the organic electrochemical transistor, The cell impedance measured above is transmitted to the PC terminal for analysis through a lock-in amplifier, and the concentration, quantity, activity and size of the cells are obtained.

The microfluidic channel is made of polydimethylsiloxane, polymethyl methacrylate, Flexdym or polyvinylidene fluoride elastomer.

Specifically, two organic electrochemical transistors are provided, and the two organic electrochemical transistors are placed in a vertically symmetrical structure, and the drains of the two organic electrochemical transistors are connected in parallel to the input end of the data readout circuit.

The metal gate of the organic electrochemical transistor is processed and manufactured on the elastic polymer polymer material, the metal source and the metal drain of the organic electrochemical transistor are processed and manufactured on the polymer thermoplastic polymer polymer material, and the conductive polymer material is used. The material realizes the conduction between the source and the drain of the organic electrochemical transistor, and the patterning process of the conductive polymer material is completed on parylene or through JRP nano-coating technology.

The first signal generation circuit specifically uses a waveform generator, the second signal generation circuit specifically uses a power amplifier, and the data readout circuit specifically uses a transimpedance amplifier.

The electrodes in the focusing area specifically adopt cone-shaped electrodes to realize cell detection.

The measurement of the cell impedance by the organic electrochemical transistor is based on the detection of the dielectric properties of the cell.

The measuring electrodes on the microfluidic device are all perpendicular to the direction of fluid flow in the microfluidic channel.

The organic electrochemical transistor reads drain current at low frequency and gate current at high frequency.

Compared with the prior art, the present invention has the following beneficial effects: the organic semiconductor-based impedance flow cytometer provided by the present invention is connected to the electrode in the focus area through the signal generation circuit to generate dielectrophoretic force to act on the cells, and the organic electrochemical transistor is used to measure the The impedance signal of the cell is sent to the lock-in amplifier by the data readout circuit, and the electrical impedance signal is analyzed by the software matched with the lock-in amplifier, and the concentration, quantity, activity and size of the cell are obtained. ; The present invention can reveal more comprehensive cell characteristics by analyzing the impedance of a single cell.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing:

Fig. 1 is the structural representation of the impedance flow cytometer based on organic semiconductor of the present invention;

Fig. 2 is a schematic structural view of the entrance focusing area electrode used for dielectrophoretic focusing at the entrance of the sample of the present invention;

Fig. 3 is a simplified circuit model diagram when a single cell of the present invention passes through an electrode;

Fig. 4 is the structural representation that two organic electrochemical transistors of the present invention are placed;

5 is a schematic diagram of the fabrication process of a microfluidic channel using PDMS;

Fig. 6 is the circuit schematic diagram of the present invention adopting symmetrical organic electrochemical transistor to measure cell impedance;

In the figure: 1 is a PCB board, 2 is a lock-in amplifier, 3 is a PC terminal, 4 is a microfluidic device, 5 is a microfluidic channel, 6 is a cell, 7 is an organic electrochemical transistor, 8 is a first signal generating circuit, 9 is the second signal generation circuit, 10 is the data readout circuit, 11 is the focus area electrode, 12 is the culture medium capacitance, 13 is the cell membrane, 14 is the cell membrane capacitance, 15 is the cytoplasm resistance, 16 is the culture medium resistance, 17 is the cytoplasm , 18 is an electric double layer capacitor, 19 is a gate, 20 is a source, 21 is a drain, 22 is a silicon wafer with a patterned photoresist, 23 is an ultra-thick photoresist, 24 is a PDMS prepolymer, 25 is a reagent introduction inlet.

Detailed ways

As shown in Figures 1 to 6, the present invention provides an impedance flow cytometer based on organic semiconductors, including a microfluidic system and a digital lock-in amplifier, wherein the digital lock-in amplifier includes a lock-in amplifier 2 and a PC terminal 3 , wherein the PC terminal 3 is provided with software supporting the lock-in amplifier 2 to analyze and process the signal, and the present invention adopts the MFLI digital lock-in amplifier and its supporting software.

The microfluidic system of the present invention includes a microfluidic device 4 welded to the PCB board 1, a first signal generating circuit 8, a second signal generating circuit 9 and a data readout circuit 10, and the microfluidic device 4 is provided with a microfluidic channel 5 and an organic electrochemical transistor 7, the cell 6 enters the microfluidic system through the microfluidic channel 5, the cell impedance is amplified by the organic electrochemical transistor 7, and at least two organic electrochemical transistors 7 are used to differentially adjust the cell impedance Take measurements.

The entrance of the microfluidic channel 5 of the present invention is provided with a tapered focusing region electrode 11 as shown in Figure 2, and the first signal generating circuit 8 and the second signal generating circuit 9 are connected to the upper and lower ends of the focusing region electrode 11 to generate a dielectric The swimming force acts on the cell 6; the lock-in amplifier 2 is connected to the first signal generating circuit 8, the second signal generating circuit 9 and the data readout circuit 10, wherein, the internal processing module of the lock-in amplifier 2 processes the signal; The signal reading is carried out on the PC terminal 3, in which, the supporting software on the PC terminal 3 analyzes the signal collected by the lock-in amplifier 2, and the concentration, quantity and activity of the cells can be obtained by analyzing the impedance signal generated by the cells flowing through the AC electric field and size information.

The first signal generating circuit 8 of the present invention is a waveform generator, the second signal generating circuit 9 is a power amplifier, the AC signal is generated by the lock-in amplifier 2, further generated by the waveform generator and amplified by the power amplifier. The data readout circuit 10 is a transimpedance amplifier, and the transimpedance amplifier measures the response current from the bottom electrode in a differential manner, that is, reads out the drain 21 current of the two organic electrochemical transistors 7, and converts it into a voltage, which is controlled by phase-locking Amplifier 2 is connected to PC terminal 3 for analysis.

The microfluidic channel 5 of the present invention can be made of elastomers such as polydimethylsiloxane (PDMS), polymethylmethacrylate (PMMA), Flexdym, and polyvinylidene fluoride (PVDF).

The present invention uses the organic electrochemical transistor 7 to measure the cell impedance based on the detection of cell dielectric properties. The current response of the organic electrochemical transistor 7 to different frequencies can be used to measure different parameters of the cell.

The placement structure of the source 20, the drain 21 and the grid 19 of the two organic electrochemical transistors 7 of the present invention is symmetrical up and down, as shown in Figures 4 and 6, the two grids generate alternating voltages with opposite phases through the signal generating circuit , the source is grounded, and a differential circuit is formed by reading the potential difference at the same position near the drain. The symmetrical placement of two organic electrochemical transistors 7 can form an ideal differential output while suppressing harmful common-mode signals.

The metal grid of the organic electrochemical transistor 7 of the present invention is processed and manufactured on the elastic polymer polymer material; the conductive polymer material is used for conduction between the source electrode and the drain electrode, and the patterning process of the conductive polymer material needs to be carried out It is completed on parylene or through JRP nano-coating technology, and the metal source and metal drain are processed and manufactured on thermoplastic polymer polymer materials.

The measurement electrodes of the microfluidic device 4 of the present invention are all perpendicular to the direction of fluid flow in the microfluidic channel 5 .

Figure 1 is a schematic diagram of the structure of the organic semiconductor-based impedance flow cytometer of the present invention. Impedance spectroscopy and microfluidic flow cytometer are combined to form a lab-on-a-chip device that can perform label-free impedance characterization of single cells. Cells 6 or particles are dispersed in a liquid, usually an electrolyte such as phosphate-buffered saline (PBS), and pumped through microfluidic channels 5 . In the microfluidic system, the lock-in amplifier 2 and the waveform generator generate an AC signal, and the signal is amplified by the power amplifier, causing the current to flow between the electrodes. A transimpedance amplifier differentially measures the response current from the bottom electrode and converts it to a voltage. The measuring electrode in the microfluidic system is an organic electrochemical transistor 7 .

The models that each device adopts in the embodiment of the present invention are respectively: waveform generator AD5930, power amplifier AD8132, transimpedance amplifier MAX4416, wherein waveform generator AD5930, power amplifier AD8132, transimpedance amplifier MAX4416 and microfluidic device 4 are all installed in a dedicated on the PCB board 1, as shown in Figure 1. This keeps the connections between components short, minimizing signal reflections and noise coupling into the system. The power amplifier is necessary because the frequency-dependent impedance of the microfluidic channel 5 does not match the output impedance of the digital-to-analog converter (DAC). Its close placement with the microfluidic device 4 ensures that signal integrity is maintained throughout the frequency range. The purpose of the transimpedance amplifier is to convert the differential response current into a voltage, which can be measured by an analog-to-digital converter (ADC).

The focusing area electrode 11 of DEP focusing is tapered, as shown in FIG. 2 . Conical electrodes can guide the movement of cells 6 towards the reservoir at the desired angle and are an efficient separation technique. The upper and lower electrodes are respectively connected to the first signal generator 8 and the second signal generator 9 . Using the AC electric field generated by the lock-in amplifier 2, the first signal generator 8 and the second signal generator 9, a dielectrophoretic force is formed, which acts on the cell 6 along the electric field intensity gradient, and the cell 6 with certain dielectric properties in the dielectric medium The force generated by the interaction with the unevenly distributed external electric field in the microfluidic channel 5 is called dielectrophoretic force. There is an electric field of minimum strength in the center of the tapered channel, and dielectrophoretic forces accelerate the particles up to this point, thereby concentrating them in a single stream in the center of the channel. An advantage of this method over others such as hydrodynamic focusing is that it allows the cells 6 to be focused in three dimensions, since the focusing forces act on the cells 6 rather than on the fluid. Furthermore, when the electrodes are designed with a small gap, cells 6 with a diameter of 10 μm can be focused, and cells 6 with even smaller diameters can be focused.

The current response of the impedance flow cytometer proposed by the present invention to different frequencies can be used for the measurement of different parameters of the cell 6 . At low frequencies, the cell membrane presents a significant barrier to current flow, and the impedance amplitude determines the size of the cell6. The conductivity of the detection volume depends only on the relative volume of the cells 6 . At intermediate frequencies, cell membrane polarization is reduced and impedance measurements provide information on membrane properties. At high frequencies, cell membrane polarization is minimal and the measurements provide information on intracellular structure and the interior of the cell.

Fig. 3 is a simplified circuit model diagram when a single cell of the present invention passes through an electrode, measuring the cell membrane capacitance 14 inside the cell membrane 13, the cytoplasm resistance 15 inside the cytoplasm 17, and the medium resistance 16 and the medium capacitance 12, the coplanar microelectrode surface and The electric double layer capacitance 18 between the medium. The impedance of the microfluidic system is dominated by the electric double layer capacitance 18 in the low frequency range. Therefore, the sensitivity is very low to detect a unit in the impedance channel. The electric double layer capacitance 18 at the electrode-electrolyte interface gradually decreases with increasing frequency. At the same time, the sensitivity of the microfluidic system increases when the absolute amplitude of the signal is affected by the cell size. In the frequency range of 1 MHz-100 MHz, the polarization of the interface between the cell 6 and the suspension medium leads to the increase of the electric field, which is the main factor of the impedance change. When the frequency ω increases to a higher range, ie ω>100 MHz, the cell membrane capacitance 14 is effectively short-circuited, and the impedance depends on the cytoplasmic resistance 15 .

The conductivity of the suspension medium plays an important role in determining the sensitivity of the detection principle. Cells 6 can only be detected if the conductivity of the cytoplasm 17 is significantly different from that of the suspension medium, since the measurement method used in the present invention can only detect changes in the dielectric properties between electrodes. Secondly, the higher the conductivity of the medium, the smaller the channel resistance, the lower the sharpness of the resonance peak, and the lower the sensitivity. For simplicity and reproducibility of results, deionized water suspension medium was used.

The materials used to manufacture the microfluidic channel 5 must have biocompatibility and flexibility in shape design, so that the cells 6 in the microfluidic channel 5 maintain their biological characteristics. Elastomeric materials such as polydimethylsiloxane (PDMS), polymethylmethacrylate (PMMA), Flexdym, or polyvinylidene fluoride (PVDF) are biocompatible, flexible in shape, and easily bonded to glass substrates or silicon substrate bonded. It is compatible with microelectronics fabrication processes and can fabricate structures a few micrometers in size. The elastomer layer with the channel structure can be connected to the glass/silicon chip through electrodes to form an encapsulated microfluidic device 4 . In most cases, microfluidic channels 5 are formed in the elastomer, which can resist most of the electrodes' contact with the fluid, thereby improving the sensitivity of the electrodes.

FIG. 4 is a schematic diagram of the arrangement of two organic electrochemical transistors in the present invention. The two organic electrochemical transistors 7 are connected in parallel to complete differential measurement of signals. The organic electrochemical transistor 7 is capable of converting biological signals into electrical signals with high gain. The sensitivity of the organic electrochemical transistor 7 as an impedance sensor can be enhanced by tuning the channel area according to a wide tissue resistance range. The organic electrochemical transistor 7 reads out the drain current at low frequencies and the gate current at high frequencies. By reading different currents, the response in the full frequency range can be measured, which overcomes the problem of large noise at low frequencies of traditional chips. The current response of the organic electrochemical transistor 7 to different frequencies can be used to measure different parameters of the cell 6 . For example, low frequency can obtain cell size, medium frequency can study cell membrane parameters, and high frequency can reflect cytoplasmic information. When the organic electrochemical transistor 7 is used as the electrode, analyzing the transconductance curve can optimize the signal-to-noise ratio of the medium and low frequency current response.

Figure 5 is a schematic diagram of the fabrication process of microfluidic channels using PDMS, and PDMS microchips can be fabricated by microscale molding processes. In laboratory use, the silicon wafer 22 with patterned photoresist can be used as a mold master. In order to have a relatively thick microfluidic channel 5 and microchamber structure for transporting reagents and samples, an ultra-thick photoresist 23 of SU-8 type is used. After compression molding, the PDMS prepolymer 24 is poured into the mold master. Then the cured PDMS prepolymer 24 is peeled off from the master plate and pasted on the plate, and the reagent inlet 25 is drilled on the plate in advance, and the plate is made of glass. PDMS prepolymers 24 can be replicated to fine structures with sub-micron feature sizes. Through the simple molding process shown in FIG. 5 , a microfluidic channel 5 structure with a smooth surface can be obtained.

Fig. 6 is a schematic circuit diagram of the present invention using symmetrical organic electrochemical transistors to measure cell impedance, and the miniature sinusoidal signal generating circuit is generated by a waveform generator AD5930 based on DDS technology. The data readout circuit is composed of cross-group amplifier MAX4416 and MFLI lock-in amplifier.

The sinusoidal voltage signal (from 100kHz to 1MHz) required for the impedance is generated by a dedicated off-the-shelf component (AD5930) based on solid Direct Digital Synthesis (DDS) technology. The differential output current is converted into a voltage by a fully differential transimpedance power amplifier AD8132. The current flowing through the channel, between the power supply and the sensing electrodes, is amplified and converted to a voltage by the MAX4416 transimpedance amplifier. To avoid any faradic current contribution due to electrochemical reactions on the electrodes, all electrodes are biased at the same DC potential, as shown in VCM, set to an intermediate level of power dynamics (1.75V relative to power ground). This is the baseline for potential and sinusoidal signals entering the virtual ground.

The AD5930 Waveform Generator is a dedicated off-the-shelf component based on underpinning Direct Digital Synthesis (DDS) technology. It is a waveform generator with programmable frequency sweep and output burst capability. With embedded digital processing, frequency control can be enhanced, and the device generates synthesized analog or digital frequency-stepped waveforms. The waveform starts at a known phase and increases in phase continuously, which makes the phase shift easy to determine. Consuming only 8mA, the AD5930 provides a convenient low power solution for waveform generation. The AD5930 can operate in several modes. In continuous output mode, the device outputs the desired frequency for a defined length of time before switching to the next frequency. In burst mode, the device outputs its frequency for a period of time, then returns to the intermediate frequency for a predefined length of time before going to the next frequency.

The AD8132 Power Amplifier is a low cost differential or single-ended input differential output amplifier with resistor-set gain. Differential signal processing reduces the effect of ground noise that plagues ground reference systems. The AD8132 can be used for differential signal processing (gain and filtering) throughout the signal chain, easily simplifying the conversion between differential and single-ended components.

The MAX4416 cross-bank amplifier combines high-speed performance, low distortion, and ultralow supply current. The cross-group amplifier MAX4416 is a unity-gain stable dual op amp with a bandwidth of 400MHz-3dB and a slew rate of 200V/µs.

What needs to be explained about the specific structure of the present invention is that the connection relationship between the various component modules used in the present invention is definite and achievable. Except for the special instructions in the embodiments, its specific connection relationship can bring corresponding Technical effects, and based on the premise of not relying on the execution of corresponding software programs, solve the technical problems proposed by the present invention. The components, modules, and specific components in the present invention, the models of the components, and the interconnection methods are brought about by the above technical features. The routine use methods and expected technical effects, unless otherwise specified, belong to the published content in patents, journal articles, technical manuals, technical dictionaries, and textbooks that can be obtained by those skilled in the art before the filing date, or belong to the field Conventional technology, common knowledge and other existing technologies need not be repeated, so that the technical solution provided in this case is clear, complete and achievable, and the corresponding physical products can be reproduced or obtained according to the technical means.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (9)

1. An impedance flow cytometer based on an organic semiconductor, characterized in that: the micro-fluidic system comprises a micro-fluidic device, a first signal generating circuit, a second signal generating circuit and a data reading circuit which are integrated on a PCB (printed circuit board), wherein the micro-fluidic device comprises a micro-fluidic channel for enabling cells to enter the micro-fluidic system and at least two electromechanical chemistry transistors for measuring cell impedance, a focusing area electrode is arranged at a sample inlet of the micro-fluidic channel, and the first signal generating circuit and the second signal generating circuit are respectively connected to the upper end and the lower end of the focusing area electrode to generate dielectrophoresis force acting on the cells;

the phase-locked amplifier generates alternating current signals and transmits the alternating current signals to the focusing region electrode through the first signal generating circuit and the second signal generating circuit, the data reading circuit realizes differential measurement of cell impedance by reading drain current of the organic electrochemical transistor, and the measured cell impedance is transmitted to the PC end through the phase-locked amplifier for analysis, so that concentration, quantity, activity and size of cells are obtained.

2. An organic semiconductor based impedance flow cytometer according to claim 1, wherein: the microfluidic channel is formed by using an elastomer made of polydimethylsiloxane, polymethyl methacrylate, flexdym or polyvinylidene fluoride materials.

3. An organic semiconductor based impedance flow cytometer according to claim 1, wherein: the organic electrochemical transistors are arranged in two, the organic electrochemical transistors are arranged in an up-down symmetrical structure, and the drains of the two organic electrochemical transistors are connected in parallel to the input end of the data reading circuit.

4. An organic semiconductor based impedance flow cytometer according to claim 3, wherein: the metal grid electrode of the organic electrochemical transistor is manufactured on an elastic polymer high polymer material, the metal source electrode and the metal drain electrode of the organic electrochemical transistor are manufactured on a high polymer thermoplastic polymer high polymer material, conduction between the source electrode and the drain electrode of the organic electrochemical transistor is realized by adopting a conductive high polymer material, and the patterning process of the conductive high polymer material is finished on parylene or by a JRP nano coating technology.

5. An organic semiconductor based impedance flow cytometer according to claim 1, wherein: the first signal generating circuit specifically adopts a waveform generator, the second signal generating circuit specifically adopts a power amplifier, and the data reading circuit specifically adopts a transimpedance amplifier.

6. An organic semiconductor based impedance flow cytometer according to claim 1, wherein: the focusing area electrode specifically adopts a conical electrode to realize cell detection.

7. An organic semiconductor based impedance flow cytometer according to claim 1, wherein: the measurement of cell impedance by the organic electrochemical transistor is based on the dielectric properties of the cell.

8. An organic semiconductor based impedance flow cytometer according to claim 1, wherein: the measuring electrodes on the microfluidic device are all perpendicular to the direction of fluid flow in the microfluidic channel.

9. An organic semiconductor based impedance flow cytometer according to claim 1, wherein: the organic electro-chemical transistor senses drain current at low frequencies and gate current at high frequencies.

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