Cell broadband detection method based on terahertz artificial surface plasmon transmission line

Abstract

The present invention discloses a method for wide-spectrum detection of cells based on terahertz surface plasmon polariton (SSPP) transmission lines, belonging to the field of wide-spectrum detection of cells. The steps are as follows: design the structure and size of the terahertz SSPP transmission line, and prepare a detection chamber encapsulated with the terahertz SSPP transmission line; connect the detection chamber to a terahertz test platform, and let the blood sample to be measured flow into the detection chamber, then start the test platform; use the high-resolution and large-dynamic terahertz frequency-domain scanning test technology to irradiate the incident terahertz beam onto the upper surface of the transmission line. The incident terahertz free-space wave is efficiently coupled with the transmission line, and SSPP waves with high localization characteristics are excited on the surface of the transmission line; obtain the phase, amplitude, and cut-off frequency data of the SSPP wave transmission spectrum, analyze the terahertz spectral characteristics of the cells, and realize non-contact, label-free, highly sensitive detection and qualitative identification of wide-spectrum information of the cells.

Description

Technical Field

[0001] The present invention belongs to the field of cell broadband detection, and particularly relates to a cell broadband detection method based on a terahertz spoof surface plasmon polariton transmission line. Background Art

[0002] Terahertz waves refer to electromagnetic waves with frequencies between 0.1 - 10 THz. Their wavelengths are close to the cell scale, and they have low radiation energy, with advantages such as non-invasiveness and non-ionization. At the same time, they are particularly sensitive to water, the most abundant substance in living organisms, and are expected to capture the electrical property differences according to the changes in cell water content, solving the problems of non-contact, high-sensitivity, and label-free accurate quantitative identification of cells.

[0003] With the continuous development of terahertz technology, it has shown broad application prospects in the field of biosensing. At present, the main methods for detecting biological cells using terahertz waves can be roughly divided into three types: The first is terahertz metasurface resonance technology, which uses artificial electromagnetic metasurfaces to construct terahertz resonant devices, and then utilizes the high-Q value characteristics of resonant devices to achieve the differential detection of biological cells; the second is the free space method, which directly irradiates samples with terahertz waves to achieve the differential detection of biological cells; the third method is the transmission line method, which uses various terahertz waveguide / transmission line devices to detect substances such as micron-scale cell particles or solutions. However, among the above three methods, it is difficult for the resonance method and the free space method to achieve broadband detection of single cells, and they are currently mostly used for the detection of cell solutions or biological tissue press tablets. Although the transmission line method has the potential to achieve broadband detection of single cells, it is still in the stage of simulation exploration, and no targeted design has been carried out for sensor performance, chamber packaging, test procedures, etc. according to the actual situations such as cell inherent characteristics and test platform performance. Since the broadband detection method takes into account the dispersion characteristics of substances and can perform efficient cell qualitative identification and analysis, it is urgent to design a systematic single-cell broadband detection method based on the transmission line method.

[0004] Terahertz spoof surface plasmon polariton (SSPP) transmission lines have advantages such as convenient feeding, high coupling efficiency, low transmission loss, and high localization, and can achieve the efficient transmission of ultra-wideband terahertz signals. Using terahertz SSPP transmission lines to detect single micron-scale cells can significantly improve the interaction effect between microcells and terahertz waves, and has important application value in microcell sensing.

[0005] Considering factors such as the difficulty of power feeding, coupling efficiency, transmission loss, and micro-nano manufacturing process, the present invention proposes to use a terahertz artificial surface plasmon transmission line as a cell sensor. By utilizing the high localization characteristics of the SSPP wave, the interaction effect between cell particles and terahertz waves is enhanced. In cooperation with a commercial high-frequency resolution terahertz scanning test platform, such as the 364X series network analyzer of CETC Instruments, the PNA network analyzer of Keysight Technologies, and the VDI spread spectrum amplifier collaborative configuration series, high-sensitivity detection of single cells in the 0.1 - 2 THz wide spectrum can be achieved as follows. Summary of the Invention

[0006] In view of the above problems existing in the prior art, the present invention proposes a cell wide-spectrum detection method based on a terahertz artificial surface plasmon transmission line, which is reasonably designed, solves the deficiencies of the prior art, and has good effects.

[0007] The cell wide-spectrum detection method based on a terahertz artificial surface plasmon transmission line includes the following steps:

[0008] S1. Design the structure and size of the terahertz artificial surface plasmon transmission line, and the artificial surface plasmon is abbreviated as SSPP;

[0009] S2. Prepare a detection chamber encapsulated with a terahertz SSPP transmission line;

[0010] S3. Connect the detection chamber to a terahertz test platform. The terahertz test platform includes a vector network analyzer, two spread spectrum modules, a terahertz emission module, a terahertz signal receiving module, and a host computer. The vector network analyzer is respectively connected to the host computer and two spread spectrum modules. The two spread spectrum modules are respectively connected to the detection chamber through the terahertz emission and receiving modules. The liquid inflow and outflow ports of the detection chamber are respectively connected to a microfluidic chip;

[0011] S4. Import the blood sample of the patient to be tested into the microfluidic chip connected to the liquid inflow port. After microfluidic enrichment and screening, it then flows into the detection chamber, and then directly start the terahertz signal scanning test module, or wait until the background liquid is emptied and then start;

[0012] S5. Through the terahertz signal emission module, guide the incident terahertz wave to the upper surface of the terahertz SSPP transmission line in the detection chamber. The incident terahertz wave is efficiently coupled with the transmission line, and a terahertz SSPP wave with high localization characteristics is excited on the surface of the transmission line;

[0013] S6. The terahertz SSPP wave on the surface of the transmission line in the chamber interacts with the cell particles in the trench channel, causing changes in the amplitude-frequency and phase-frequency characteristics of the transmission coefficient spectrum. Use the terahertz signal receiving module to receive the SSPP wave containing complete cell information;

[0014] S7. Analyze the terahertz spectral characteristics of the phase, amplitude, and cut-off frequency of the received SSPP wave transmission spectrum data to achieve non-contact and label-free precise qualitative identification of cells.

[0015] Further, in S1, the structure of the terahertz SSPP transmission line includes a substrate. The substrate is made of a low-dielectric and high-transparency material, including photoresist and polytetrafluoroethylene. A grid unit is provided on the upper surface of the substrate. The grid unit includes a plurality of grids that are distributed at one-dimensional periodic intervals along the length direction of the substrate. The surface of the grid is coated with a gold film, and the thickness of the gold film is greater than the skin depth of terahertz waves within the working frequency band.

[0016] Further, the matrix grid includes a flat part and transition parts located at both ends of the flat part. The grid heights of the flat part are the same, and the grid heights of the transition parts are designed to be gradually changed. The gradual change methods include gradient change, sine change, and cosine change. The gradient change is designed such that the grid height is i = 1,..., m, where i represents the i-th grid in the transition part, m is the number of grids in the transition part, and h is the grid height of the flat part.

[0017] Further, in S1, according to the terahertz frequency band range to be detected, design the size of the terahertz SSPP transmission line to ensure that the cut-off frequency of the terahertz SSPP transmission line is within the working frequency band of the terahertz signal transmitting and receiving module. Specifically:

[0018] The width g of a single groove between the grids is slightly larger than the cell diameter to ensure that the groove can form a microfluidic detection area and allow cell particles to pass through. The number of grooves is designed according to the actual requirements of the detection area.

[0019] Make a preliminary estimate of the transmission line size, and its expression is:

[0020]

[0021] Define the length direction of the substrate as the x direction, the width direction of the substrate as the y direction, and the height direction of the substrate as the z direction. In the formula, k x is the propagation constant of the SSPP wave, k0 is the wave number of the free space wave, h is the height of the grid in the z direction of the flat part, p is the period length of the unit cell in the x direction, that is, the sum of the width of a single groove and the thickness of the grid, and g is the width of a single groove in the x direction. Make a preliminary estimate of h and p through formula (1) to make the two of the same order of magnitude, so as to be suitable for processing.

[0022] Then, by changing h, p, and g of the transmission line, calculate the dispersion curve using simulation software, and further adjust the cut-off frequency of the transmission line to ensure that the cut-off frequency is within the working frequency band range of the terahertz signal transmitting and receiving module, so as to obtain the final sizes of h, p, and g of the transmission line.

[0023] Further, in S2, the preparation of the detection chamber encapsulating the terahertz SSPP transmission line is specifically as follows:

[0024] The detection chamber includes a detection part and a covering part in the shape of a cuboid. The detection part and the covering part are made of the same material as the substrate. The upper surface of the detection part is used as the substrate. According to the designed dimensions, a grid unit structure is etched on the upper surface of the detection part, and then metal coating is carried out to form a terahertz SSPP transmission line;

[0025] Pour or deposit the encapsulation material on the surface of the transmission line grid and inside the trench until it fills the transmission line trench and exceeds the top of the grid unit by about the radius of the cell to be measured, and then stop;

[0026] Using ultraviolet lithography, liquid inflow and outflow channels are etched on both sides in the y direction of the grid in the flat part. The widths of the liquid inflow and outflow channels are designed according to actual detection requirements and are less than or equal to the total length of the grid in the flat part; the height of the liquid inflow channel is approximately equal to the sum of the grid height and the radius of the cell to be measured, and the bottom of this channel is flush with the bottom of the transmission line trench. The height of the liquid outflow channel is approximately equal to the radius of the cell to be measured, and the bottom of this channel is flush with the top of the transmission line grid;

[0027] The encapsulation material filled in the grid in the central area of the flat part needs to be completely cleaned to form a cell microfluidic channel. The number of grids in the central area of the flat part is designed according to actual needs. The encapsulation material filled in the grids at both ends of the flat part and the grids in the transition part needs to be etched to a smooth plane on the upper surface;

[0028] Finally, the upper surface of the detection part is bonded to the covering part, and the two channels cooperate with the covering part to form a liquid inflow port and a liquid outflow port, thus obtaining a complete detection chamber.

[0029] Further, in S3, the terahertz signal transmitting and receiving module includes two types. The first type is a terahertz waveguide, including a rectangular waveguide and a microstrip line. The second type is a terahertz antenna, including various types of horn antennas and photoconductive antennas;

[0030] When excited by the antenna, the radiation beam of the antenna is directly irradiated onto the upper surface of the terahertz SSPP transmission line, and the beam incident angle is adjusted until the insertion loss is the lowest. When excited by the waveguide, it is connected and positioned to the detection chamber by using a flange. Specifically:

[0031] On the premise of ensuring that the excitation port is aligned with the position of the terahertz SSPP transmission line, according to the position and specifications of the positioning holes of the flange, positioning holes of the same size are drilled at the corresponding positions on the two sides of the detection chamber without liquid inflow and outflow ports.

[0032] Further, in S3, during the detection process, the chamber inversion detection method or the chamber upright detection method is adopted. In the chamber inversion detection method, the cells stay on the upper surface of the covering part, and at this time, the cell center is basically aligned with the top of the grid of the flush part, so as to better match the cell with the region of the strongest electric field on the surface of the transmission line. In the chamber upright detection method, the cell center is aligned with the top of the grid of the transmission line, so as to better match the cell with the region of the strongest electric field on the surface of the transmission line.

[0033] The beneficial technical effects brought by the present invention:

[0034] The present invention discloses a method for wide-spectrum detection of cells based on a terahertz artificial surface plasmon polariton transmission line, which solves the problem of high-sensitivity wide-spectrum detection of the electrical characteristics of single cells at the micron scale. By designing a high-performance SSPP transmission line with grooves slightly larger than the cell diameter, it is ensured that the cells can pass through the field concentration region. Then, a packaging chamber is designed to encapsulate the SSPP transmission line inside the chamber, so that the cells are not interfered by the changes in the background environment during the detection process, greatly improving the detection sensitivity. Using a high-frequency resolution and large-dynamic scanning test platform in the terahertz frequency band, the change law of the scattering parameters of the transmission line is detected and analyzed to achieve high-sensitivity detection of wide-spectrum cell characteristic information. Description of the Drawings

[0035] Figure 1 It is the structure of the terahertz SSPP transmission line designed in the present invention;

[0036] Among them, (a) is the front view of the grid of the transition part; (b) is the front view of the grid of the flush part; (c) is the three-dimensional structure diagram of the transmission line;

[0037] Figure 2 It is the etching diagram on the surface of the detection part in the present invention;

[0038] Figure 3 It is the perspective view of the upright detection chamber in the present invention;

[0039] Figure 4 It is the detection schematic diagram in the present invention;

[0040] Figure 5 It is the connection schematic diagram of the detection chamber and the flange in the present invention;

[0041] Figure 6 It is the cell detection flow chart in the present invention;

[0042] Figure 7 It is the schematic diagram of the detection system in the present invention; Specific Embodiments

[0043] The following further describes the specific embodiments of the present invention with reference to specific embodiments:

[0044] A method for wide-spectrum detection of cells based on a terahertz surface plasmon polariton transmission line, comprising the following steps:

[0045] S1. Design the structure and dimensions of a terahertz SSPP transmission line, where surface plasmon polaritons are abbreviated as SSPP;

[0046] The spatial terahertz wave has a very weak response to substances at the cell scale. Considering the high localization characteristics of the SSPP wave, it can amplify the signal changes caused by substances and can achieve wide-spectrum detection. In order to improve the wide-spectrum detection sensitivity of cells, a terahertz SSPP transmission line is selected as the cell sensor;

[0047] The structure of the terahertz SSPP transmission line includes a substrate, and the substrate is made of a low-dielectric and high-transparency material, such as photoresist and polytetrafluoroethylene, etc.; a grid unit is provided on the upper surface of the substrate. The grid unit includes a number of grids distributed at intervals in a one-dimensional periodic array along the length direction of the substrate. The length direction of the substrate is defined as the x direction. The cross-sectional shape of the grid along the x direction can be trapezoidal, rectangular or triangular. In this embodiment, the trapezoidal shape is taken as an example. The grid surface is coated with a gold film, and the thickness of the gold film is greater than the skin depth of the terahertz wave within the working frequency band. This transmission line is compatible with current traditional semiconductor processing technologies. The surface grid structure can be processed by ultraviolet lithography or plasmon etching, etc., and the gold film can be prepared by magnetron sputtering, etc.

[0048] The grid unit includes a flat part and transition parts located at both ends of the flat part, as Figure 1 shown in (a) and (b). The grid heights of the flat part are the same, and the grid heights of the transition parts are designed to be gradually changing, so that the phase constant of the SSPP wave on the grid structure gradually changes to be close to the phase constant of the free space wave, improving the coupling efficiency between the incident terahertz wave and the SSPP transmission line. The gradual change methods include gradient gradual change, sine gradual change and cosine gradual change; for gradient gradual change, the grid height is designed as i = 1,..., m, where i represents the i-th grid in the transition part, h is the grid height of the flat part, and m is the number of grids in the transition part. m can be reasonably adjusted according to the total number of grid sections of the transmission line.

[0049] According to the terahertz frequency band range to be detected, design the dimensions of the terahertz SSPP transmission line to ensure that the cut-off frequency of the terahertz SSPP transmission line is within the working frequency band of the terahertz signal transmitting and receiving module. Specifically:

[0050] The width g of a single groove between grids is slightly larger than the cell diameter to ensure that the groove can form a microfluidic detection area and allow cell particles to pass through. The number of grooves is designed according to the actual needs of the detection area;

[0051] Make a preliminary estimate of the transmission line dimensions, and its expression is:

[0052]

[0053] Define the length direction of the substrate as the x - direction, the width direction of the substrate as the y - direction, and the height direction of the substrate as the z - direction; where h is the height of the grid in the z - direction of the flush part, p is the period length of the unit section in the x - direction, that is, the sum of the width of a single groove and the thickness of the grid, g is the width of a single groove in the x - direction, k0 is the wave number of the free - space wave, and k x is the propagation constant of the SSPP wave, representing the wave number along the propagation direction on the dielectric interface, that is, the x - direction; initially estimate h and p through formula (1) to make the two of the same order of magnitude, so as to be suitable for processing;

[0054] The cut - off frequency of the transmission line is ultimately determined by the size of the transmission line. After initially estimating the size of the transmission line, a rough cut - off frequency is selected, and then the size of the transmission line is adjusted continuously to achieve the required cut - off frequency. Use simulation software to calculate the dispersion curve, and then regulate the cut - off frequency of the transmission line to ensure that the cut - off frequency is within the working frequency band range of the terahertz signal transmitting and receiving module, so as to obtain the final sizes of h, p, and g of the transmission line. Since during processing, processing errors will cause changes in the size of the transmission line, which in turn leads to changes in the cut - off frequency, a certain margin needs to be reserved when setting the cut - off frequency to ensure that the processed SSPP transmission line does not exceed the upper limit of the measurement range of the terahertz signal generating and receiving module.

[0055] The overall structure of the designed terahertz SSPP transmission line is as shown in Figure 1 (c) of, the length of the transmission line is L, L=(N + 2i)*p, where N is the number of grid sections in the flush part and i is the number of grid sections in the single - side transition part.

[0056] S2. Prepare a detection chamber encapsulating the terahertz SSPP transmission line, specifically:

[0057] The detection chamber includes a cuboid - shaped detection part and a covering part. The detection part and the covering part are made of the same material as the substrate. Use the upper surface of the detection part as the substrate, etch the grid unit structure on the upper surface of the detection part according to the designed size, and then perform metal coating to form the terahertz SSPP transmission line;

[0058] Pour or deposit encapsulating material on the surface of the transmission - line grid and inside the grooves until it fills the transmission - line grooves and exceeds the top of the grid unit by about the radius of the cells to be measured and then stop;

[0059] The liquid inflow and outflow channels are etched on both sides of the grid in the y - direction of the flush part by ultraviolet lithography. The widths of the liquid inflow and outflow channels are designed according to actual detection requirements and are less than or equal to the total length of the grid in the flush part. The height h of the liquid inflow channel is approximately equal to the sum of the grid height and the radius of the cell to be measured. The bottom of this channel is flush with the bottom of the transmission line groove. The height of the liquid outflow channel is approximately equal to the radius of the cell to be measured, and the bottom of this channel is flush with the top of the grid in the flush part. This design can ensure that the cells stay in the detection area on the transmission line and will not be discharged with the liquid, thereby avoiding the interference of the background solution during the detection process and improving the detection sensitivity.

[0060] The encapsulation material filled in the grid in the central area of the flush part needs to be completely cleaned to form a cell micro - flow channel. The number of grids in the central area of the flush part is designed according to actual needs. The encapsulation material filled in the grids at both ends of the flush part and the grids in the transition part needs to etch the upper surface into a smooth plane, as Figure 2 shown;

[0061] Finally, bond the upper surface of the detection part with the covering part to ensure that the liquid cannot flow into the feeding end along the transmission line, resulting in contamination of the test module. The liquid inflow and outflow channels cooperate with the covering part to form a liquid inflow port and a liquid outflow port, thus obtaining a complete detection chamber. The detection chamber can be used in a right - side - up or inverted manner. The right - side - up detection chamber is as Figure 3 shown.

[0062] S3. As Figure 6 and 7 shown, build a test system, connect the detection chamber to the terahertz test platform. The terahertz test platform includes a vector network analyzer, two spread - spectrum modules, a terahertz emission module, a terahertz signal reception module, and a host computer. The vector network analyzer is connected to the host computer and the two spread - spectrum modules respectively. The two spread - spectrum modules are connected to the detection chamber through the terahertz emission and reception modules respectively. The liquid inflow and outflow ports of the detection chamber are connected to a microfluidic chip respectively;

[0063] There are two types of terahertz signal emission and reception modules. The first type is the terahertz waveguide, including rectangular waveguides, microstrip lines, etc. The second type is the terahertz antenna, including various types of horn antennas, photoconductive antennas, etc.;

[0064] When excited by the antenna, directly irradiate the radiation beam of the antenna onto the upper surface of the terahertz SSPP transmission line, and adjust the beam incident angle until the insertion loss is the lowest. When excited by the waveguide, it is necessary to use a flange to connect and position with the detection chamber, as Figure 5As shown, on the premise of ensuring the alignment of the excitation port and the terahertz SSPP transmission line, according to the position and specifications of the flange positioning holes, positioning holes of the same size are drilled at the corresponding positions on the two sides of the detection chamber that do not have liquid inflow and outflow ports, so as to improve the coupling efficiency between the terahertz wave and the transmission line while taking into account the chamber positioning, and to carry out cell detection.

[0065] During the detection process, the chamber inversion detection method or the chamber upright detection method can be adopted. In the chamber inversion detection method, the cells stay on the upper surface of the covering part. At this time, the cell center is basically aligned with the top of the grid of the flush part, as Figure 4 shown, so as to achieve a perfect match between the cells and the region with the strongest electric field on the surface of the transmission line; in the chamber upright detection method, the cell center is aligned with the top of the grid of the transmission line to achieve a better match between the cells and the region with the strongest electric field on the surface of the transmission line.

[0066] S4. Import the blood sample of the patient to be tested into the microfluidic chip connected to the liquid inflow port. After microfluidic enrichment and screening, it then flows into the detection chamber, and then directly start the test platform, or wait until the background liquid is emptied and then start;

[0067] S5. Through the terahertz signal emission module, guide the incident terahertz beam to the upper surface of the terahertz SSPP transmission line in the detection chamber. The incident terahertz wave is efficiently coupled with the transmission line, and a terahertz SSPP wave with high localization characteristics is excited on the surface of the transmission line;

[0068] S6. The terahertz SSPP wave on the surface of the transmission line in the chamber interacts with the cell particles in the trench channel, causing changes in the amplitude-frequency and phase-frequency characteristics of the transmission coefficient spectrum. Use the terahertz signal receiving module to receive the SSPP wave containing complete cell information;

[0069] S7. By analyzing the terahertz spectral characteristics of the phase, amplitude, and cut-off frequency of the transmitted spectrum data of the received SSPP wave, non-contact and label-free accurate qualitative identification of cells is achieved.

[0070] The terahertz SSPP transmission line proposed in the present invention is used as a cell sensor. Utilizing the high localization characteristics of the SSPP wave, the interaction effect between cell particles and terahertz waves is improved, and it is coordinated with a commercial high-frequency resolution terahertz scanning test platform, such as the 364X series network analyzer of CETC Instruments, the PNA network analyzer of Keysight Technologies, and the VDI spread spectrum co-configuration series, so as to achieve high-sensitivity detection of single cells in the 0.1-2 THz wide spectrum. Since the current commercial instruments can only reach 0.1-1.5 THz, when test instruments capable of reaching the 1.5-2 THz frequency band appear in the future, high-sensitivity detection of single cells in the 1.5-2 THz wide spectrum can be achieved.

[0071] Certainly, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. A cell wide-spectrum detection method based on terahertz artificial surface plasmon transmission lines, characterized in that: The following steps are involved: S1. Design the structure and dimensions of the terahertz artificial surface plasmon transmission line. Artificial surface plasmon is referred to as SSPP. S2, preparing a detection chamber encapsulated with a terahertz SSPP transmission line; S3, connecting the detection chamber to a terahertz test platform, wherein the terahertz test platform includes a vector network analyzer, two spectrum spreading modules, a terahertz transmitting module, a terahertz signal receiving module, and a host computer, wherein the vector network analyzer is connected to the host computer and the two spectrum spreading modules respectively, and the two spectrum spreading modules are connected to the detection chamber through the terahertz transmitting and receiving modules respectively, and the liquid inlet and outlet ports of the detection chamber are connected to a microfluidic chip respectively; S4, introducing the blood sample of the patient to be tested into the microfluidic chip connected to the liquid inlet port, and then flowing into the detection chamber after microfluidic enrichment and screening, and then directly starting the test platform, or waiting for the background liquid to be emptied before starting; S5. The incident terahertz wave is guided to the upper surface of the terahertz SSPP transmission line in the detection chamber through the terahertz signal transmitting module, the incident terahertz wave is efficiently coupled with the transmission line, and a terahertz SSPP wave with a high localized characteristic is excited on the surface of the transmission line; S6, the terahertz SSPP wave on the surface of the transmission line in the chamber interacts with the cell particles in the groove channel, so that the amplitude-frequency and phase-frequency characteristics of the transmission coefficient spectrum change, and the SSPP wave containing complete cell information is received by the terahertz signal receiving module; S7. By analyzing the terahertz spectrum characteristics of the phase, amplitude, and cutoff frequency of the received SSPP wave transmission spectrum data, non-contact, label-free, accurate qualitative identification of cells can be achieved; In S1, the structure of the terahertz SSPP transmission line includes a substrate, the substrate is made of low dielectric and high light transmittance materials, including photoresist and polytetrafluoroethylene; a grid unit is provided on the upper surface of the substrate, the grid unit includes a plurality of grids spaced in a one-dimensional periodic array along the length direction of the substrate, and the grid surface is plated with a gold film, the thickness of the gold film is greater than the skin depth of the terahertz wave in the working frequency band; The grid unit includes a flat portion and transition portions at both ends of the flat portion. The grid heights of the flat portions are the same. The grid heights of the transition portions are designed to be gradually transitioned. The gradual transition modes include gradient gradual change, sine gradual change and cosine gradual change. The gradient gradual change is designed to have a grid height of i=1,...,m, i represents the i-th grid in the transition part, m is the number of grids in the transition part, and h is the height of the grid in the flush part; In S2, a detection chamber encapsulating a terahertz SSPP transmission line is prepared, specifically: The detection chamber includes a detection part and a covering part in a rectangular parallelepiped shape. The detection part and the covering part are made of the same material as the substrate. The upper surface of the detection part is used as the substrate. A grid unit structure is etched on the upper surface of the detection part according to the designed size, and then metal plating is performed to form a terahertz SSPP transmission line. Pour or deposit packaging materials on the surface of the transmission line grid and inside the groove until the transmission line groove is filled and exceeds the height of the top of the grid by about the radius of the cell to be measured; The liquid inlet and outlet channels are respectively etched on both sides of the flat grid in the y direction by ultraviolet photolithography. The widths of the liquid inlet and outlet channels are designed according to the actual detection requirements and are both less than or equal to the total length of the flat grid. The height of the liquid inlet channel is approximately equal to the sum of the grid height and the radius of the cell to be tested, and the bottom of the channel is flush with the bottom of the transmission line groove. The height of the liquid outflow channel is approximately equal to the radius of the cell to be tested, and the bottom of the channel is flush with the top of the transmission line grid. The packaging material filled with the grid in the center area of ​​the flush part needs to be completely cleaned to form a cell microfluidic channel. The number of grids in the center area of ​​the flush part is designed according to actual needs. The packaging material filled with the grids at both ends of the flush part and the grids in the transition part needs to have the upper surface etched into a smooth plane. Finally, the upper surface of the detection part is bonded to the covering part, and the two channels cooperate with the covering part to form a liquid inlet port and a liquid outlet port, thereby obtaining a complete detection chamber.

2. The cell wide-spectrum detection method based on terahertz artificial surface plasmon transmission line according to claim 1 is characterized in that: In S1, the size of the terahertz SSPP transmission line is designed according to the terahertz frequency band to be detected, ensuring that the cutoff frequency of the terahertz SSPP transmission line is within the working frequency band of the terahertz signal transmitting and receiving module, specifically: The width g of a single groove between the grids is slightly larger than the cell diameter, ensuring that the grooves can form a microfluidic detection area and allow cell particles to pass through. The number of grooves is designed according to the actual needs of the detection area; A preliminary estimate of the transmission line size is given by: The length direction of the substrate is defined as the x direction, the width direction of the substrate is defined as the y direction, and the height direction of the substrate is defined as the z direction; where k x is the propagation constant of the SSPP wave, k0 is the wave number of the free space wave, h is the height of the flat grid in the z direction, p is the length of the unit node period in the x direction, that is, the sum of the width of a single groove and the thickness of the grid, and g is the width of a single groove in the x direction. h and p are preliminarily estimated by formula (1) to make them in the same order of magnitude, thus suitable for processing; Then, by changing the h, p, and g of the transmission line, the dispersion curve is calculated using simulation software, and the cutoff frequency of the transmission line is adjusted to ensure that the cutoff frequency is within the operating frequency band of the terahertz signal transmitting and receiving modules, thereby obtaining the final dimensions of h, p, and g of the transmission line.

3. The cell wide-spectrum detection method based on terahertz artificial surface plasmon transmission line according to claim 2 is characterized in that: In S3, the terahertz signal transmitting and receiving module includes two types, the first type is a terahertz waveguide, including a rectangular waveguide and a microstrip line, and the second type is a terahertz antenna, including various types of horn antennas and photoconductive antennas; When excited by the antenna, the antenna radiation beam is directly irradiated onto the upper surface of the terahertz SSPP transmission line, and the beam incident angle is adjusted until the insertion loss is minimum. When excited by the waveguide, the flange is used to connect and position with the detection chamber, specifically: Under the premise of ensuring that the excitation port is aligned with the terahertz SSPP transmission line, positioning holes of the same size are drilled at corresponding positions on the two sides of the detection chamber without liquid inlet and outlet ports according to the position and specifications of the flange positioning holes.

4. The cell wide-spectrum detection method based on terahertz artificial surface plasmon transmission line according to claim 3 is characterized in that: In S3, the chamber inversion detection method or the chamber upright detection method is used during the detection process. In the chamber inversion detection method, the cell is allowed to stay on the upper surface of the covering part, and the center of the cell is basically aligned with the top of the grid of the flat part, thereby achieving better matching between the cell and the area with the strongest electric field on the surface of the transmission line; in the chamber upright detection method, the center of the cell is aligned with the top of the grid of the transmission line, thereby achieving better matching between the cell and the area with the strongest electric field on the surface of the transmission line.

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