Organ chip unit, chip and research method

Abstract

The invention provides an organ chip unit for simulating the pathogenesis of rheumatoid arthritis, and belongs to the technical field of cell culture. The chip comprises a top-layer chip, a bottom-layer chip and a middle microporous membrane, the top-layer chip and the bottom-layer chip are separated by the middle microporous membrane, and the middle microporous membrane is used for enabling cells in a cell culture space of the top-layer chip and cells in a cell culture space of the bottom-layer chip not to be in direct contact, but interaction of signal molecules and substance exchange can be carried out; synovial cells and cartilage cells are injected into the bottom-layer chip or the top-layer chip to be cultured. According to the invention, multi-cell three-dimensional co-culture can be realized. Through the additional stress stimulation co-culture part, the influence of pressure or tension on the cell environment can be judged, and the actual condition that rheumatoid arthritis joints receive pressure or tension for a long time can be simulated. The synovial cells and the cartilage cells are used, so that the structure of the inflammation joint in a living body can be truly reflected, and the interaction among various cell tissues can be reflected.

Description

Technical Field

[0001] The present invention relates to the field of cell culture technology, and in particular to an organ chip unit for simulating the pathogenic mechanism of rheumatoid arthritis, an organ chip comprising the organ chip unit, and a method for studying the pathogenic mechanism of rheumatoid arthritis. Background Art

[0002] Simulating and studying the inflammation of joints is of great significance for studying the pathogenic mechanism of rheumatoid arthritis and screening drugs for the treatment of rheumatoid arthritis. In recent years, in vitro cell culture or organoid culture has gradually replaced some unethical or too resource-intensive research that cannot be conducted on living animals.

[0003] In the existing technology, organoid culture for rheumatoid arthritis is mostly static culture of a single cell. This culture method cannot well reflect the three-dimensional growth relationship of cells; it cannot reflect the results of the interaction of multiple cells in the body; and it cannot reflect the situation where joint-related cells in the body are under pressure or tension for a long time. In terms of drug development and disease research, both a large number of cell experiments and a large number of animal experiments are inevitable. In the process of crossing from cell experiments to animal experiments, the time cost, cultivation cost, moral cost and monetary cost of extracting cells or cell culture cannot be ignored. In the process of buying from animal experiments to human experiments, it is necessary to cross species differences step by step and gradually approach animals with similar genes to humans, which greatly increases the cost of various animal experiments. At the same time, due to the individual differences of animals and the uncontrollability of environmental factors, the reproducibility of animal experiments is poor, which will consume additional time and energy of researchers in the field of biology or medicine. However, for the safety and practicality of the research, multiple groups and multiple rounds of animal experiments are indispensable. Therefore, the construction of an in vitro model of organ chips for rheumatoid arthritis is particularly important. The construction of organ chips aims to construct a simulated physiological environment and stimulation environment in vivo on organ chips.

[0004] In addition, in clinical or scientific research, there is a gradual tendency to discuss the results of multi-cell interactions. In today's scientific research process, cell research is still mainly carried out after single cell culture in a culture dish. This method has great limitations. Various cell experiments can only reflect the feedback of one cell, ignoring the interaction between cells; in addition, multiple experiments on different cells increase the manpower and time costs. For the construction of a multi-cell co-culture system, the barrier material between the two cells is very important; although the surface can be treated to improve its properties, the material for constructing the barrier also needs to be explored. Fibrin is a glycoprotein synthesized and secreted by hepatocytes. As a natural material, it has excellent biocompatibility. It can be prepared into a microporous membrane as a barrier material by using electrospinning technology with polylactic acid-glycolic acid copolymer. At the same time, the materials commonly used for cell adhesion on the market are mostly high-specification engineering polymer materials, such as polycarbonate (PCTE) or polypropylene (PP), and their safety needs to be considered. In addition, cells in the body, especially inflammatory cells in joints, are under stress stimulation for a long time. In today's in vitro models, this condition is ignored, and the lack of this condition is an important defect in static cell culture. Therefore, a tool that can co-culture multiple types of cells at the same time is needed; and through linkage design, batch experiments can be carried out to control the variable conditions in the experimental process to be consistent, which greatly saves time in the experimental process and reduces the uncontrollability in the experiment. Summary of the invention

[0005] In view of this, in order to solve the technical problems that the prior art cannot well simulate the interaction of multiple cells in the body, there is no three-dimensional multi-cell culture environment, and it is impossible to provide certain stress stimulation during the cell co-culture process, in the first aspect, the present invention provides an organ chip unit that simulates the pathogenic mechanism of rheumatoid arthritis, which separates the top chip and the bottom chip by an intermediate microporous membrane, thereby realizing multi-cell three-dimensional co-culture. Greatly save costs in the process of drug research. The use of primary fibroblast-like synovial cells and chondrocytes can truly reflect the structure of inflamed joints in the body and can reflect the interaction between multiple cell tissues. By stress stimulating the lamellar cells in the lamellar cell co-culture cavity of the circular part of the chip, simulating the situation where the synovial cells and chondrocytes in the body are subjected to pressure or tension for a long time, the variables in the in vitro culture of cells can be better controlled, and the mutual culture relationship between the several can be explored. It has broad application prospects in the fields of cell biomedicine, signal pathway analysis, and screening of therapeutic drugs related to rheumatoid arthritis.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] An organ chip unit for simulating the pathogenic mechanism of rheumatoid arthritis, comprising:

[0008] a top chip having a microfluidic channel and a cell culture space, wherein the microfluidic channel has an inlet and an outlet;

[0009] A bottom chip having a microfluidic channel and a cell culture space, wherein the microfluidic channel has an inlet and an outlet;

[0010] An intermediate microporous membrane, located between the top chip and the bottom chip, for separating the top chip and the bottom chip, so that cells in the cell culture space of the top chip and cells in the cell culture space of the bottom chip do not directly contact each other, but can interact with each other and exchange substances;

[0011] Primary fibroblast-like synovial cells are used for injection into the top chip or the bottom chip for culture, and chondrocytes are used for injection into the bottom chip or the top chip for culture.

[0012] Preferably, the top chip and the bottom chip have overlapping parts as the cell co-culture part;

[0013] Preferably, the cell co-culture portion can be stimulated by external pressure or external tension.

[0014] Preferably, the surfaces of the top chip, the bottom chip and the middle microporous membrane are treated with oxygen plasma to improve the hydrophilicity and wettability of the microporous membrane, thereby facilitating cell adhesion.

[0015] Preferably, the surface of the intermediate microporous membrane is treated with oxygen plasma and then coated with an extracellular matrix to achieve cell adhesion.

[0016] Preferably, the pore size of the intermediate microporous membrane is 0.2 um to 5 um.

[0017] Preferably, the top chip is one of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA) and polycarbonate (PC);

[0018] The bottom chip is one of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA) and polycarbonate (PC);

[0019] The intermediate microporous membrane is one of polyethylene terephthalate (PET), polycarbonate (PC), polylactic acid (PLA), polylactic acid-glycolic acid copolymer (PLGA) and fibrin electrostatic spinning membrane.

[0020] Preferably, the microfluidic channel is a micrometer-scale flow channel.

[0021] Preferably, two sealing board layers are further included, which are respectively located on the top chip and the bottom chip for realizing packaging.

[0022] In a second aspect, the present invention provides an organ chip for simulating the pathogenic mechanism of rheumatoid arthritis, comprising at least one of the above-mentioned organ chip units for simulating the pathogenic mechanism of rheumatoid arthritis.

[0023] In a third aspect, the present invention provides a method for studying the pathogenic mechanism of simulating rheumatoid arthritis, comprising the following steps:

[0024] Step S1: inoculating synovial cells and chondrocytes into the cell culture space of the top chip and the cell culture space of the bottom chip of the organ chip simulating the pathogenic mechanism of rheumatoid arthritis as claimed in claim 9 to achieve co-culture of the two cells;

[0025] Step S2: inputting culture medium to culture cells;

[0026] Step S3: applying pressure stimulation to the co-culture area by an external pressure pump or applying tension stimulation by a horizontal tension machine to simulate the stress conditions in vivo;

[0027] Step S4: by controlling the type and concentration of the drug in the cell culture space to adjust, the in vitro simulation of the drug administration process is achieved, and the lysis solution is injected to obtain protein for analysis or the cell secretion signal molecules are evaluated by fluorescent staining to achieve drug evaluation and screening;

[0028] Step S5: Control variables and study the pathogenic mechanism of rheumatoid arthritis by secreting signal molecules from cells during cell co-culture and stimulating cells with different signal molecules.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The organ chip unit for simulating the pathogenic mechanism of rheumatoid arthritis provided by the present invention realizes multi-cell three-dimensional co-culture by separating the top chip and the bottom chip with an intermediate microporous membrane. The interaction between chondrocytes and fibroblast-like synovial cells and the interaction between rheumatoid arthritis are studied with the help of microfluidic equipment. In addition, with the help of a pressure pump and a horizontal tensile machine, the present invention can stimulate cells by externally applying stress to simulate the environment in which the cell tissue in the body is under long-term pressure. In addition, it greatly saves time and labor costs in the process of drug research, and can also reduce the ethical costs of researchers by reducing large-scale animal experiments.

[0031] The present invention can truly reflect the structure of inflamed joints in vivo by using primary fibroblast-like synovial cells and chondrocytes, and can reflect the interaction between multiple cell tissues. By studying cells under stress stimulation, it reflects the influence of multiple cells on the pathogenic cause of rheumatoid arthritis when they are stimulated by external forces at the same time and for a long time. It has broad application prospects in the fields of cell biomedicine, signal pathway analysis, and screening of therapeutic drugs related to rheumatoid arthritis.

[0032] The organ chip provided by the present invention is easy to observe, has a simple structure, uses primary cells, uses a small amount of culture fluid and reagents, is convenient for parallel culture, and can achieve precise batch parallel experiments through microfluidic technology.

[0033] The present invention adopts a co-culture system of chondrocytes and synovial cells, which is closer to the structure and microenvironment of the joint in vivo, and is a better cell culture system for simulating the joint environment in vitro. Cell culture is carried out by microfluidic equipment, which avoids the labor cost of tedious manual replacement of culture medium and ensures the stability of the cell culture environment.

[0034] The establishment of organ chips based on chondrocytes and synovial cells can complete cell culture under the premise of a stable internal environment for subsequent research on the pathogenic mechanism of rheumatoid arthritis; at the same time, it can also realize the screening of rheumatoid arthritis drugs and the optimization of drug concentration through batch parallel experiments.

[0035] The organ chip unit provided by the present invention adopts a two-layer cell co-culture system. Both layers of cells grow on the middle microporous membrane and can be connected to each other through the liquid in the internal environment (the middle microporous membrane can allow the culture fluid to flow between each other), so as to exchange substances and interact with signal molecules, influence and promote each other, and ensure that the two cells will not devour each other when co-cultured. Synovial cells and chondrocytes have good stability, are suitable for miniaturization and industrialization, and have broad application prospects in the fields of cell biomedicine related to rheumatoid arthritis, signal pathway analysis, and screening of therapeutic drugs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 An exploded view of the organ chip unit provided by the present invention;

[0037] Figure 2 A cross-sectional view of the organ chip unit provided by the present invention;

[0038] Figure 3 Schematic diagram of using a press to press the cell co-culture area to stimulate cells after the chip is assembled;

[0039] Figure 4The fluorescence staining comparison diagram of the intermediate microporous membrane adhesion experiment, among which, PET-FLS: the membrane material is PET, the adhesion of fibroblast-like synoviocytes; PET-AC: the membrane material is PET, the adhesion of chondrocytes; PCTE-FLS: the membrane material is PCTE (polycarbonate track-etched membrane), the adhesion of fibroblast-like synoviocytes; PCTE-AC: the membrane material is PCTE, the adhesion of chondrocytes; DAPI: (4',6-diamidino-2-phenylindole), cell nucleus staining; FITC (fluorescent isothiocyanate), TRITC (tetrabromofluorescein ketone): cytoskeleton staining; Merge: refers to merging images of multiple fluorescence channels into an overall image; ESEM: environmental scanning electron microscope; (the scale of the fluorescence image is 200μm, and the scale of the ESEM image is 50μm)

[0040] Figure 5 This is a fluorescence staining image of co-culturing FLS cells and AC cells using the traditional method; (the scale of the fluorescence image is 200μm)

[0041] Figure 6 The live cell fluorescence staining images of FLS cells and AC cells co-cultured in the organ chip using PET as the membrane material (1-7 days) (the scale of the fluorescence image is 200 μm);

[0042] In the figure, 1, top chip; 2, bottom chip; 3, middle microporous membrane; 4, microfluidic channel; 41, inlet; 42, outlet. DETAILED DESCRIPTION

[0043] like Figure 1-3 As shown, the present invention provides an organ chip unit for simulating the pathogenic mechanism of rheumatoid arthritis, comprising:

[0044] The top chip 1 has a microfluidic channel 4 and a cell culture space, wherein the microfluidic channel 4 has an inlet 41 and an outlet 42, wherein the microfluidic channel 4 is used for cell inoculation and for input, diversion and diffusion of culture fluid;

[0045] Wherein, the top chip 1 is preferably one of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA) and polycarbonate (PC);

[0046] A bottom chip 2, which has a microfluidic channel 4 and a cell culture space, wherein the microfluidic channel 4 has an inlet 41 and an outlet 42, wherein the microfluidic channel 4 is used for cell inoculation and for input, diversion and diffusion of culture fluid;

[0047] Wherein, the bottom chip 2 is preferably one of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA) and polycarbonate (PC);

[0048] The middle microporous membrane 3 (with good biocompatibility) is located between the top chip 1 and the bottom chip 2, and is used to separate the top chip 1 and the bottom chip 2, so that the cells in the cell culture space of the top chip 1 and the cells in the cell culture space of the bottom chip 2 do not directly contact each other, but can interact with each other and exchange substances;

[0049] Among them, the intermediate microporous membrane 3 is preferably one of polyethylene terephthalate (PET), polycarbonate (PC), polylactic acid (PLA), polylactic acid copolymer (PLGA) and fibrin electrospinning membrane;

[0050] Primary fibroblast-like synovial cells are injected into the top chip 1 or the bottom chip 2 for culture, and chondrocytes are injected into the bottom chip 2 or the top chip 1 for culture.

[0051] The organ chip unit for simulating the pathogenic mechanism of rheumatoid arthritis provided by the present invention separates the top chip 1 and the bottom chip 2 by using an intermediate microporous membrane 3, and culture synovial cells and chondrocytes respectively, thereby realizing multi-cell three-dimensional co-culture, and the cell co-culture part can be stimulated by external pressure or external tension. It greatly saves costs in the process of drug research. The use of primary fibroblast-like synovial cells and chondrocytes can truly reflect the structure of inflamed joints in vivo, and can reflect the interaction between multiple cell tissues. It has broad application prospects in the fields of cell biomedicine, signal pathway analysis, and screening of therapeutic drugs related to rheumatoid arthritis.

[0052] like Figure 1 As shown, the top chip 1 and the bottom chip 2 are separated by an intermediate microporous membrane 3 to form a "sandwich" structure. Cells are inoculated in the cell culture spaces on the upper and lower sides of the intermediate microporous membrane 3. The presence of the intermediate microporous membrane 3 prevents the cells in the upper and lower cell culture spaces from directly contacting each other, but allows for the interaction of signal molecules and the exchange of substances.

[0053] In the present invention, the top chip 1 and the bottom chip 2 have overlapping parts (referring to the parts separated by the middle microporous membrane 3) as the cell co-culture part.

[0054] In the present invention, the surfaces of the top chip 1, the bottom chip 2 and the middle microporous membrane 3 are treated with oxygen plasma to improve the hydrophilicity and wettability of the microporous membrane, thereby facilitating cell adhesion.

[0055] In the present invention, the surface of the intermediate microporous membrane 3 is treated with oxygen plasma and then coated with an extracellular matrix to achieve cell adhesion.

[0056] In the present invention, the pore size of the intermediate microporous membrane 3 is preferably 0.2 um to 5 um, and the thickness is preferably 150 um, which effectively blocks cells from passing through the porous membrane and serves as a support for cell growth.

[0057] In the present invention, the microfluidic channel 4 is a micron-level flow channel, and the effective depth of the microfluidic channel 4 is preferably 200um, the effective depth of the intermediate cell culture chamber (the intermediate cell culture chamber constitutes a structure for simulating the culture of inflammatory joints in vitro) is 400-450um (the sum of the heights of the upper and lower layers of the cell culture space of the intermediate microporous membrane 3), and the total height of the organ chip is preferably 5-10mm.

[0058] In the present invention, two sealing plate layers are also included, which are respectively located on the top chip 1 and the bottom chip 2, for realizing packaging, preferably by hot pressing to perform tight bonding.

[0059] The present invention also provides a method for preparing the above-mentioned organ chip unit, comprising the following steps:

[0060] (1) designing and drawing the microstructure and microfluidic channel 4 patterns of the top chip 1 and the bottom chip 2 in the organ chip unit by computer-aided design software, and processing them on the surface of the top chip 1 and the bottom chip 2 respectively by micromachining technology using a micro-milling tool;

[0061] (2) preparing PDMS raw materials by mixing initiator and dimethylsiloxane in a ratio of 1:10, pouring an appropriate amount of PDMS into a mold, and preparing a PDMS substrate with a microfluidic channel by vacuum degassing, high temperature curing, and demolding, and processing the top chip 1 and the bottom chip 2 using a micro-milling tool;

[0062] (3) The top chip 1, the bottom chip 2 and the middle microporous membrane 3 are subjected to oxygen plasma treatment on the surface, and the middle microporous membrane 3 is sandwiched between the top chip 1 and the bottom chip 2 to form a sandwich structure, and the bonding is assisted by hot pressing.

[0063] (4) The primary cell suspension of fibroblast-like synovial cells and chondrocytes is injected into the cell culture space of the top chip 1 and the bottom chip 2 through the microfluidic channel 4 for cell inoculation.

[0064] In a second aspect, the present invention provides an organ chip for simulating the pathogenic mechanism of rheumatoid arthritis, comprising at least one of the above-mentioned organ chip units for simulating the pathogenic mechanism of rheumatoid arthritis, such as N (N≥2) integrated together for use to achieve simultaneous culture of multiple types of cells.

[0065] In a third aspect, the present invention provides a method for studying the pathogenic mechanism of simulating rheumatoid arthritis, comprising the following steps:

[0066] Step S1: inoculating synovial cells and chondrocytes into the cell culture space of the top chip 1 and the cell culture space of the bottom chip 2 of the organ chip simulating the pathogenic mechanism of rheumatoid arthritis as claimed in claim 9 to achieve co-culture of the two cells;

[0067] Step S2: inputting culture fluid to culture cells, preferably using a microfluidic device to input the culture fluid to achieve the purpose of automatically replacing the culture fluid and culturing cells;

[0068] Step S3: applying pressure stimulation to the co-culture area by an external pressure pump or applying tension stimulation by a horizontal tension machine to simulate the stress conditions in vivo;

[0069] Step S4: by controlling the type and concentration of drugs in the cell culture space, the in vitro simulation of the drug administration process is achieved, and it can be observed under a microscope; injecting lysis solution to obtain protein for analysis or evaluating cell secretion signal molecules through fluorescent staining to achieve drug evaluation and screening;

[0070] Step S5: Control variables and study the pathogenic mechanism of rheumatoid arthritis by secreting signal molecules from cells during cell co-culture and stimulating cells with different signal molecules (such as tumor necrosis factor (TNF-α), lipopolysaccharide (LPS) and interleukin-6 (IL-6), etc.).

[0071] The technical effect of selecting chondrocytes and synovial cells to truly reflect the structure of inflamed joints in vivo is verified in conjunction with specific examples, as follows:

[0072] In rheumatoid arthritis, fibroblast-like synoviocytes (FLS) and chondrocytes (AC) are important disease-influencing factors and are indispensable in in vitro culture research. The microporous membrane in the organ chip is the main scaffold for cell adhesion, so the selection of the microporous membrane is particularly important. Figure 4 As shown in the figure, two commonly used microporous membranes: polyethylene terephthalate (PET) and polycarbonate (PC) were optimized, and the cell adhesion of FLS and AC was evaluated, and the cells were fluorescently stained with 4',6-diamidino-2-phenylindole (DAPI) and fluorescein isothiocyanate-phalloidin (FITC), and the environmental electron scanning microscope was used to magnify and photograph the cell morphology for optimization. From the fluorescence image information, it can be found that the PET membrane is relatively dominant in the number of cell adhesion for FLS cells and AC cells; from the ESEM image information, it can be found that for the morphology of a single cell, the cell morphology on the PET membrane is more spread and has better adhesion. Relatively speaking, the cells on the PCTE membrane are more curled up, and the relative area of ​​cell adhesion and cell material exchange in different flow channels is smaller, which is not conducive to the mutual influence between the two cells.

[0073] The advantage of the present invention over the traditional method is that direct co-cultivation cannot reflect normal phenomena in vivo, such as Figure 5 As shown, direct co-culture of FLS cells and AC cells revealed:

[0074] AF555 is a specific dye for labeling FLS, and FITC is a fluorescent dye for two cytoskeletons. It can be seen that the FLS cells labeled with red light continuously invade the AC cells from the first day to the third day after co-culture. After the invasion, the number of AC cells becomes less and less, and the two cells cannot be stably co-cultured, so subsequent research and application cannot be carried out.

[0075] Figure 6 The organ chip is connected to the fluorescence image of cells that have been stained in vivo (cells marked with vital dyes can only emit green fluorescence). Figure 6 It can be seen that FLS cells and AC cells can stably exist and divide in the patented chip, providing a co-culture environment for practical applications.

[0076] In summary, the present invention selects PET as the intermediate microporous membrane for co-culture of FLS cells and AC cells, which has obvious advantages over traditional culture methods.

[0077] The above are only preferred specific implementations of the present invention; however, the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and improved concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An organ chip unit for simulating the pathogenic mechanism of rheumatoid arthritis, characterized in that: include: a top chip having a microfluidic channel and a cell culture space, wherein the microfluidic channel has an inlet and an outlet; A bottom chip having a microfluidic channel and a cell culture space, wherein the microfluidic channel has an inlet and an outlet; An intermediate microporous membrane, located between the top chip and the bottom chip, for separating the top chip and the bottom chip, so that cells in the cell culture space of the top chip and cells in the cell culture space of the bottom chip do not directly contact each other, but can interact with each other and exchange substances; Primary fibroblast-like synovial cells are used for injection into the top chip or the bottom chip for culture, and chondrocytes are used for injection into the bottom chip or the top chip for culture.

2. An organ chip unit for simulating the pathogenic mechanism of rheumatoid arthritis according to claim 1, characterized in that: The top chip and the bottom chip have overlapping parts, which serve as a cell co-culture part; Preferably, the cell co-culture portion is stimulated by external pressure or external tension.

3. An organ chip unit for simulating the pathogenic mechanism of rheumatoid arthritis according to claim 1, characterized in that: The surfaces of the top chip, the bottom chip and the middle microporous membrane are treated with oxygen plasma to improve the hydrophilicity and wettability of the microporous membrane, thereby facilitating cell adhesion.

4. An organ chip unit for simulating the pathogenic mechanism of rheumatoid arthritis according to claim 3, characterized in that: The surface of the intermediate microporous membrane is treated with oxygen plasma and then coated with an extracellular matrix to achieve cell adhesion.

5. The organ chip unit for simulating the pathogenic mechanism of rheumatoid arthritis according to claim 1, characterized in that: The pore size of the intermediate microporous membrane is 0.2-5 um.

6. The organ chip unit for simulating the pathogenic mechanism of rheumatoid arthritis according to claim 1, characterized in that: The top chip is one of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA) and polycarbonate (PC); The bottom chip is one of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA) and polycarbonate (PC); The intermediate microporous membrane is one of polyethylene terephthalate (PET), polycarbonate (PC), polylactic acid (PLA), polylactic acid-glycolic acid copolymer (PLGA) and fibrin electrostatic spinning membrane.

7. An organ chip unit for simulating the pathogenic mechanism of rheumatoid arthritis according to claim 1, characterized in that: The microfluidic channel is a micrometer-scale flow channel.

8. An organ chip unit for simulating the pathogenic mechanism of rheumatoid arthritis according to any one of claims 1 to 7, characterized in that: It also includes two sealing board layers, which are respectively located on the top chip and the bottom chip for realizing packaging.

9. An organ chip that simulates the pathogenic mechanism of rheumatoid arthritis, characterized in that: An organ chip unit comprising at least one of claims 1 to 8 that simulates the pathogenic mechanism of rheumatoid arthritis.

10. A method for studying the pathogenic mechanism of rheumatoid arthritis, characterized in that: The steps include: Step S1: inoculating synovial cells and chondrocytes into the cell culture space of the top chip and the cell culture space of the bottom chip of the organ chip simulating the pathogenic mechanism of rheumatoid arthritis as claimed in claim 9 to achieve co-culture of the two cells; Step S2: inputting culture medium to culture cells; Step S3: by controlling the type and concentration of the drug in the cell culture space, the in vitro simulation of the drug administration process is achieved, and the lysis solution is injected to obtain protein for analysis or the cell secretion signal molecules are evaluated by fluorescent staining to achieve drug evaluation and screening; Step S4: Control variables and study the pathogenic mechanism of rheumatoid arthritis by secreting signal molecules from cells during cell co-culture and stimulating cells with different signal molecules.

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