A 3d synovial cartilage organ-on-a-chip with biomimetic structure

Abstract

The utility model provides a kind of 3D synovial cartilage organ chip of bionic structure, it is related to organ chip manufacturing technical field.It includes main part;The main part includes top layer, cartilage layer, joint synovial fluid layer, synovial membrane and endothelium channel layer that are sequentially arranged;Cartilage cavity for accommodating articular chondrocyte is provided in the cartilage layer;Synovial fluid cavity for accommodating joint synovial fluid is provided in the joint synovial fluid layer;Synovial membrane channel and immune cell channel are arranged in parallel in the synovial membrane and endothelium channel layer;Permeation zone is arranged between the synovial membrane channel and the immune cell channel;Pressure cavity is provided in the top layer, and pressure cavity is provided with elastic diaphragm on the side of cartilage cavity.This scheme integrates mechanical stimulation into organ chip, can reproduce in-vivo periodic compression when human walking / activity, to more truly simulate cartilage-synovial membrane-bone interface mechanical-chemical coupling, to improve the similarity of in-vitro model.

Description

Technical Field

[0001] This utility model relates to the field of organ-on-a-chip technology, and in particular to a 3D synovial cartilage organ-on-a-chip with a biomimetic structure. Background Technology

[0002] Rheumatoid arthritis (RA) is currently one of the typical representatives of synovial joint diseases. RA is an immune-disrupted chronic systemic inflammatory disease characterized by cystic proliferation and chronic inflammation of the synovial tissue, as well as destruction of cartilage and bone tissue. Its incidence in adults worldwide is approximately 0.5%–1%. Neovascularization, leukocyte infiltration, and endothelial cell activation in the synovium are key aspects of RA pathological development. Literature indicates that angiogenesis in the synovial tissue generally occurs in the early stages of the disease. It can provide oxygen and nutrients to the proliferating synovial cell clusters and serve as a channel for inflammatory cell invasion, thereby continuously promoting subsequent synovial proliferation, inflammation maintenance, and joint erosion. Recent research indicates that endothelial cells not only participate in angiogenesis in the RA process but also play an active role in inflammatory regulation. In the inflammatory microenvironment, they can release pro-inflammatory and pro-angiogenic mediators and influence the angiogenesis process through post-translational modifications, thus exacerbating the development of inflammation.

[0003] In terms of treatment, there are currently a variety of drug treatments available, such as disease-modifying antirheumatic drugs (DMARDs), glucocorticoids, and biologics. However, due to the high heterogeneity of RA in terms of genotype, disease course, and clinical manifestations, existing treatments are still difficult to comprehensively and fundamentally prevent joint destruction.

[0004] Furthermore, most existing treatments do not directly address the synovial angiogenesis mechanism, which is becoming crucial for next-generation treatments and model development. Therefore, developing a synovial joint model that incorporates elements such as angiogenesis, multicellular interferometry between cartilage, endothelium, inflammation, and synovium, and cartilage destruction will greatly facilitate RA research. In particular, a platform possessing features such as high throughput, standardization, and controllable parameters can provide powerful tools for drug screening, personalized treatment, and research into the mechanisms of cartilage structure destruction.

[0005] Organ-on-chips (OoC) generally refer to miniaturized in vitro simulation platforms that culture cells in a suitable culture medium in a 3D culture environment and precisely control the extracellular environment through microfluidic technology to simulate specific functions of specific organs in vivo. After more than ten years of development, OoC technology can effectively simulate crosstalk between tissues under physiological and pathological conditions, and can also perform multi-organ co-culture to a certain extent to simulate real multi-system interactions in vivo.

[0006] Organ-on-a-chip technology can establish suitable functional units with relatively low cell and culture medium consumption, supporting projects such as disease modeling, drug evaluation, and toxicity testing. Furthermore, depending on the source of the basic cells and through large-scale industrial production, it can achieve personalized, standardized, and high-throughput drug screening, potentially becoming a novel and efficient modeling method and experimental platform for osteoarthritis. However, this technology faces the following technical challenges: a) Currently, there is a lack of in vitro models that can efficiently and in real-time intervene in and monitor cell behavior, simulate physiological and pathological states, and screen new drugs. Organ-on-a-chip based on microfluidics and 3D cell co-culture technology has great application potential in these areas as an emerging research model.

[0007] b) Traditional animal experiments are time-consuming and costly, and cannot present microscopic changes at the tissue level in real time. Existing two-dimensional cell cultures are too simple and cannot accurately reflect crosstalk between tissues or cells. The latest organ-on-a-chip technology does not incorporate mechanical simulation devices and cannot accurately reflect the physical stimulation of joints in a displayed state.

[0008] c) Existing organ-on-a-chip still requires terminating the experiment at various stages and using other observation methods to observe and verify the different states of the model during the evolution process. The solution of placing a photoelectric observation window inside the base has great application potential in observing the continuous evolution of the model. Utility Model Content

[0009] The purpose of this invention is to provide a biomimetic 3D synovial cartilage organ-on-a-chip, its preparation method and application, in order to solve at least one of the above-mentioned technical problems existing in the prior art.

[0010] In the first aspect, to solve the above-mentioned technical problems, this utility model provides a biomimetic 3D synovial cartilage organ chip, including a main body; The main body comprises, in sequence, a top layer, a cartilage layer, a synovial fluid layer, a synovium, and an endothelial channel layer; The cartilage layer contains a cartilage cavity for accommodating articular cartilage cells. The joint synovial fluid layer is provided with a synovial fluid cavity for containing the joint synovial fluid; The synovial membrane and endothelial channel layers contain parallel synovial channels and immune cell channels; an osmotic zone is provided between the synovial channels and the immune cell channels; A pressure chamber is provided inside the top layer, and an elastic membrane is provided on one side of the cartilage cavity within the pressure chamber; the outer surface of the elastic membrane is in contact with the articular cartilage cells within the cartilage cavity.

[0011] In one feasible implementation, the organ-on-a-chip further includes a working medium control system connected to the pressure chamber for inputting or outputting a working medium into the pressure chamber, controlling the pressure changes within the pressure chamber, forcing the elastic membrane to bulge or contract, thereby applying dynamically changing pressure to the articular cartilage cells.

[0012] Existing synovial organ-on-a-chip systems are usually limited to a 2D plane and lack simulation of external mechanical stimuli. Therefore, they do not have sufficient realism and are difficult to explore the intercellular interactions and regulatory mechanisms in the actual joint cavity under physiological and pathological conditions.

[0013] This application introduces a pressure chamber to simulate physical stimulation; by controlling the input and output of the working medium, the pressure change inside the pressure chamber is controlled, and this pressure change is applied to the articular cartilage cells through an elastic membrane, fully simulating the movement of articular cartilage, and thus exploring the effects of mechanical stimulation on cell-cell and tissue-tissue interactions under physiological / pathological conditions.

[0014] Preferably, the pressure changes include periodic pressure and intermittent pressure: The parameters of the periodic pressure include: a frequency range of 0.5-1 Hz, a peak strain range of 5-15%, and a cycle time of 1-4 hours; The parameters of the intermittent pressure include: a pressure value range of 3-10 MPa and a frequency of 1 Hz; This allows for precise simulation of mechanical stimulation changes in human articular cartilage, thereby inhibiting cell hypertrophy / osteogenic differentiation and facilitating the acquisition of stable hyaline cartilage-like tissue.

[0015] Preferably, the elastic film is a PDMS film made of polydimethylsiloxane (PDMS), which is not only easy to process, but also has the advantages of being transparent and breathable.

[0016] Preferably, the thickness of the elastic film is in the range of 20-30 micrometers, and it can be manufactured using existing casting processes with a film thickness of 20-30 micrometers, thereby ensuring sufficient mobility and repeatable aerodynamic response.

[0017] Furthermore, the working medium is compressed air or liquid; The working medium control system includes an air pump or a hydraulic pump, which is connected to the inlet of the pressure chamber via a delivery pipeline; the outlet of the pressure chamber is connected to a recovery pipeline; and control valves are installed on the delivery pipeline and / or the recovery pipeline to control the delivery speed and pressure value of the working medium.

[0018] Furthermore, the cartilage cavity is filled with fibrin gel containing (embedded) articular chondrocytes.

[0019] Furthermore, the cartilage cavity and the synovial cavity are stacked one on top of the other, with a first partition in the middle. The first partition has first through holes evenly distributed on it, connecting the cartilage cavity and the synovial cavity.

[0020] Furthermore, the aperture of the first via is 80-150 micrometers, preferably 100 micrometers.

[0021] The center-to-center distance between two adjacent first vias is 160-300 micrometers, preferably 200 micrometers.

[0022] Furthermore, on the horizontal projection plane, the cartilage cavity and the synovial cavity overlap at their edges, meaning that the cartilage cavity and the synovial cavity have the same shape and size.

[0023] Preferably, on the horizontal projection plane, the cartilage cavity and the synovial cavity are rectangular in shape.

[0024] Furthermore, the synovial channel is filled with fibrin gel containing synovial-derived fibroblasts; The synovial channel includes a first synovial channel and a second synovial channel; The first synovial channel, the immune cell channel, and the second synovial channel are arranged side by side in sequence; The immune cell channel is used to deliver immune cells.

[0025] Furthermore, the permeation zone includes trapezoidal columns evenly spaced along the channel axis; a third through-hole is formed between adjacent trapezoidal columns to allow mononuclear / macrophages to pass through.

[0026] Furthermore, in the cross-section of the trapezoidal column: the height of the trapezoid can be 100 micrometers; the side on the immune cell channel side is the upper base, and the width of the upper base can be in the range of 50-100 micrometers (e.g., 60 micrometers); the side on the synovial channel side is the lower base, and the width of the lower base can be in the range of 120-200 micrometers (e.g., 160 micrometers); the distance between adjacent upper bases can be 100 micrometers.

[0027] In this application, the synovial and endothelial channel layer is equivalent to implanting a cellular channel (i.e., an immune cell channel) that simulates a blood vessel in the middle of a synovial cavity. By pre-endothelializing the immune cell channel, the process of immune cells migrating from inside the blood vessel to the outside under physiological conditions can be better simulated. While observing the effects of monocyte / macrophage extravasation on cartilage and synovial cells under pathological conditions, different drugs can also be added to achieve the purpose of drug screening.

[0028] Furthermore, a second partition is provided at the bottom of the synovial cavity in the joint synovial fluid layer to separate the synovial cavity from the first synovial channel, the immune cell channel and the second synovial channel below; The second partition plate has a second through hole only at the position of the first synovial channel, which is used to connect the synovial cavity and the first synovial channel.

[0029] Thus, immune cells can migrate sequentially through the third, second, and first pores to the cartilage cavity, demonstrating a complex inflammatory migration axis involving multiple tissues, including cartilage, endothelium, inflammation, and synovium.

[0030] Furthermore, only one of the synovial channels on both sides of the immune cell channel is connected to the synovial cavity, while the other synovial channel cannot directly communicate with the synovial cavity. This creates different variables, allowing for comparative observation of the effects of synovial fluid on immune cell migration under physiological / pathological conditions.

[0031] Furthermore, the aperture of the second via is in the range of 80-150 micrometers, preferably 100 micrometers; the center distance between two adjacent second vias is in the range of 160-300 micrometers, preferably 200 micrometers.

[0032] Furthermore, a bottom layer is provided below the synovial and endothelial channel layers, which covers the first synovial channel, the immune cell channel and the second synovial channel from the bottom.

[0033] Furthermore, the underlying layer is provided with a photoelectric module array for monitoring cells in the first synovial channel, immune cell channel and / or second synovial channel, as well as physicochemical properties such as oxygen content and pH value.

[0034] The photoelectric module can be either contact or non-contact. When it is contact, its probe extends into the synovial channel and the immune cell channel.

[0035] This design is based on the fact that existing synovial organ-on-a-chip systems typically require external observation equipment to detect changes in the chip's internal physicochemical properties, cell migration, and other parameters. This often necessitates terminating the continuous culture process and wastes a significant amount of time. This organ-on-a-chip integrates photoelectric modules within the synovial and immune cell channels, enabling the monitoring of fundamental data such as oxygen content and pH levels during continuous culture. It offers advantages such as high throughput, low invasiveness, and long-term stability, making it well-suited for use with microfluidic chips.

[0036] Furthermore, two sets of first fluid exchange holes are symmetrically arranged at both ends of the top layer; a set of first fluid exchange pools are symmetrically arranged at both ends of the cartilage cavity of the cartilage layer; the first fluid exchange pools are connected to the cartilage cavity and correspond one-to-one with a set of first fluid exchange holes, and are used to exchange fluid in the cartilage cavity by gravity. A set of second fluid exchange holes is symmetrically arranged at both ends of the cartilage cavity of the cartilage layer; a set of second fluid exchange pools is symmetrically arranged at both ends of the synovial cavity of the joint synovial fluid layer; the second fluid exchange pools are connected to the synovial cavity and correspond one-to-one with a set of second fluid exchange holes and another set of first fluid exchange holes, forming two vertical channels for exchanging fluid in the synovial cavity by gravity or microfluidic means.

[0037] Furthermore, the diameter or width of the first synovial channel and the second synovial channel ranges from 400 to 600 micrometers, preferably 500 micrometers; the diameter or width of the immune cell channel ranges from 200 to 300 micrometers, preferably 250 micrometers.

[0038] Furthermore, it also includes a first microfluidic device, the output port and return port of which are respectively connected to the inlet and outlet of the first synovial channel, forcing the fibrin gel (or synovial fluid) containing fibroblasts from the synovium to circulate through the first synovial channel.

[0039] Furthermore, it also includes a second microfluidic device, the output port and return port of which are connected to the inlet and outlet of the second synovial channel, respectively, to force the fibrin gel (or synovial fluid) containing fibroblasts from the synovium to circulate through the second synovial channel.

[0040] Furthermore, it also includes a third microfluidic device, the output port and return port of which are respectively connected to the inlet and outlet of the immune cell channel for injecting immune cells into the immune cell channel.

[0041] Furthermore, it also includes a fourth microfluidic device, the output port and return port of which are respectively connected to the vertical channels at both ends of the synovial cavity, forcing the synovial fluid of the joint to circulate through the synovial cavity.

[0042] Preferably, when the immune cell channel is pre-endothelialized, human umbilical vein endothelial cells are used, and the culture medium is endothelial cell growth medium 2 (EGM-2).

[0043] Preferably, the immune cells injected into the immune cell channel are human primary mononuclear cells.

[0044] By adopting the above technical solution, this utility model has the following beneficial effects: This invention provides a biomimetic 3D synovial cartilage organ-on-a-chip that integrates mechanical stimulation into the organ-on-a-chip. It can reproduce the periodic compression that occurs in vivo during human walking / activity, thus more realistically simulating the mechanical-biochemical coupling of the cartilage-synovium-bone interface, thereby improving the similarity of in vitro models. It can promote the formation of (perfusionable / mature) cartilage-like matrix, improve nutritional / metabolic homeostasis and mechanical properties during long-term culture, and thus facilitate subsequent pharmacodynamic evaluation. It can be used as a "stress-triggered pathological stimulus" to simulate overload injury or chronic low-dose injury, thereby establishing a more clinically relevant pathological model on the organ-on-a-chip (e.g., mechanically induced inflammation and matrix degradation), which is particularly important for screening anti-inflammatory or anti-degradation candidate drugs.

[0045] This approach incorporates photoelectric modules into organ-on-a-chip, enabling real-time monitoring of dissolved oxygen (via an optical oxygen sensor), thereby directly reflecting metabolic status, vascularization / perfusion connectivity, and the impact of drugs on tissue oxygenation; it can also monitor local pH in real-time (via an optical pH probe), thereby directly reflecting the activity level of synovial inflammation and the effectiveness of drug intervention. Attached Figure Description

[0046] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0047] Figure 1 A layered exploded view of a 3D synovial cartilage organ-on-a-chip with a biomimetic structure provided for an embodiment of this utility model; Figure 2 A side cross-sectional schematic diagram of a 3D synovial cartilage organ-on-a-chip with a biomimetic structure provided for an embodiment of this utility model; Figure 3 A schematic diagram of the shape of the permeation zone provided in an embodiment of this utility model; Figure 4 This is a schematic diagram of the second via distribution provided in an embodiment of the present utility model; Figure 5 A schematic diagram of the pressure chamber provided for an embodiment of this utility model.

[0048] Figure label: 1-Pressure chamber; 2-Cartilage cavity; 3-First septum; 4-Synthetic fluid cavity; 5-Second septum; 61-First synovial channel; 62-Second synovial channel; 7-Photoelectric module array; 8-Photoelectric module signal line; 9-Immune cell channel; 101-Inlet of pressure chamber; 102-Outlet of pressure chamber; 111-Inlet of first synovial channel; 112-Inlet of second synovial channel; 12-Inlet of immune cell channel; 131-First fluid exchange hole; 132-Second fluid exchange hole; 15-Elastic membrane; 151-Natural position of elastic membrane. Detailed Implementation

[0049] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0050] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0052] The present invention will be further explained below with reference to specific embodiments.

[0053] like Figure 1-5 As shown, this embodiment provides a biomimetic 3D synovial cartilage organ-on-a-chip, comprising a main body; The main body comprises, in sequence, a top layer, a cartilage layer, a synovial fluid layer, a synovium, and an endothelial channel layer; The cartilage layer contains a cartilage cavity 2 for accommodating articular cartilage cells; The joint synovial fluid layer is provided with a synovial fluid cavity 4 for containing joint synovial fluid; The synovial membrane and endothelial channel layer are provided with synovial channels and immune cell channels 9 arranged side by side; an osmotic zone is provided between the synovial channels and immune cell channels 9; The top layer is provided with a pressure chamber 1, and an elastic membrane 15 is provided on one side of the cartilage cavity 2. The outer surface of the elastic membrane 15 is in contact with the articular cartilage cells in the cartilage cavity 2.

[0054] Furthermore, the organ-on-a-chip also includes a working medium control system, which is connected to the pressure chamber 1 and is used to input or output working medium into the pressure chamber 1, control the pressure changes in the pressure chamber 1, force the elastic membrane 15 to bulge or contract, and thus apply dynamically changing pressure to the articular cartilage cells.

[0055] Existing synovial organ-on-a-chip systems are usually limited to a 2D plane and lack simulation of external mechanical stimuli. Therefore, they do not have sufficient realism and are difficult to explore the intercellular interactions and regulatory mechanisms in the actual joint cavity under physiological and pathological conditions.

[0056] like Figure 5 As shown, this embodiment introduces a pressure chamber 1 to simulate physical stimulation; by controlling the input and output of the working medium, the pressure change inside the pressure chamber 1 is controlled, and the pressure change is applied to the articular cartilage cells through the elastic membrane 15, fully simulating the movement of articular cartilage, and thus exploring the effect of mechanical stimulation on cell-cell and tissue-tissue interactions under physiological / pathological conditions.

[0057] Preferably, the pressure changes include periodic pressure and intermittent pressure: The parameters of the periodic pressure include: a frequency range of 0.5-1 Hz, a peak strain range of 5-15%, and a cycle time of 1-4 hours; The parameters of the intermittent pressure include: a pressure value range of 3-10 MPa and a frequency of 1 Hz; This allows for precise simulation of mechanical stimulation changes in human articular cartilage, thereby inhibiting cell hypertrophy / osteogenic differentiation and facilitating the acquisition of stable hyaline cartilage-like tissue.

[0058] Preferably, the elastic film 15 is a PDMS film made of polydimethylsiloxane (PDMS), which is not only easy to process, but also has the advantages of being transparent and breathable.

[0059] Preferably, the thickness of the elastic film 15 is in the range of 20-30 micrometers, and it can be manufactured using existing casting processes with a film thickness of 20-30 micrometers, thereby ensuring sufficient mobility and repeatable aerodynamic response.

[0060] Furthermore, the working medium is compressed air or liquid; The working medium control system includes an air pump or a hydraulic pump, which is connected to the inlet 101 of the pressure chamber via a delivery pipeline; the outlet 102 of the pressure chamber is connected to a recovery pipeline; and control valves are provided on the delivery pipeline and / or the recovery pipeline to control the delivery speed and pressure value of the working medium.

[0061] Furthermore, the cartilage cavity 2 is filled with fibrin gel containing (embedded) articular chondrocytes.

[0062] Furthermore, the cartilage cavity 2 and the synovial cavity 4 are stacked one on top of the other, with a first partition 3 in the middle. The first partition 3 is uniformly provided with first through holes that connect the cartilage cavity 2 and the synovial cavity 4.

[0063] Furthermore, the aperture of the first via is 80-150 micrometers, preferably 100 micrometers.

[0064] The center-to-center distance between two adjacent first vias is 160-300 micrometers, preferably 200 micrometers.

[0065] Furthermore, on the horizontal projection plane, the cartilage cavity 2 and the synovial cavity 4 overlap at their edges, meaning that the cartilage cavity 2 and the synovial cavity 4 have the same shape and size.

[0066] Preferably, on the horizontal projection plane, the cartilage cavity 2 and the synovial cavity 4 are rectangular in shape.

[0067] Furthermore, the synovial channel is filled with fibrin gel containing fibroblasts derived from the synovium. The synovial channel includes a first synovial channel 61 and a second synovial channel 62; The first synovial channel 61, the immune cell channel 9, and the second synovial channel 62 are arranged side by side in sequence; The immune cell channel 9 is used to deliver immune cells.

[0068] Furthermore, such as Figure 3 As shown, the permeation zone includes trapezoidal columns evenly spaced along the channel axis; a third through-hole is formed between adjacent trapezoidal columns to allow mononuclear / macrophages to pass through.

[0069] Furthermore, in the cross-section of the trapezoidal column: the height of the trapezoid can be 100 micrometers; the side on one side of the immune cell channel 9 is the upper base, and the width of the upper base can be 50-100 micrometers (e.g., 60 micrometers); the side on the synovial channel is the lower base, and the width of the lower base can be 120-200 micrometers (e.g., 160 micrometers); the distance between adjacent upper bases can be 100 micrometers.

[0070] In this embodiment, the synovial and endothelial channel layer is equivalent to implanting a simulated blood vessel cell channel (i.e., immune cell channel 9) in the middle of a synovial cavity. By pre-endothelializing the immune cell channel 9, the process of immune cells migrating from inside the blood vessel under physiological conditions can be better simulated. While observing the effects of monocyte / macrophage extravasation on cartilage and synovial cells under pathological conditions, different drugs can also be added to achieve the purpose of drug screening.

[0071] Furthermore, a second partition 5 is provided at the bottom of the synovial cavity 4 in the joint synovial fluid layer to separate the synovial cavity 4 from the first synovial channel 61, the immune cell channel 9 and the second synovial channel 62 below. The second partition 5 has a second through hole at the position of the first synovial channel 61, which is used to connect the synovial cavity 4 and the first synovial channel 61.

[0072] Thus, immune cells can migrate sequentially through the third, second, and first perforations to the cartilage cavity 2, demonstrating a complex inflammatory migration axis involving multiple tissues, including cartilage, endothelium, inflammation, and synovium.

[0073] Furthermore, only one of the synovial channels on both sides of the immune cell channel 9 is connected to the synovial cavity 4, while the other synovial channel cannot directly communicate with the synovial cavity 4. This creates different variables, allowing for comparative observation of the effects of synovial fluid on immune cell migration under physiological / pathological conditions.

[0074] Furthermore, such as Figure 4 As shown, the second via is circular and arranged in a staggered manner (the first via can also be arranged in this manner); the diameter of the second via is 80-150 micrometers, preferably 100 micrometers; the center distance between two adjacent second vias is 160-300 micrometers, preferably 200 micrometers.

[0075] Furthermore, the diameter range of the first synovial channel 61 and the second synovial channel 62 is 400-600 micrometers, preferably 500 micrometers.

[0076] Furthermore, a bottom layer is provided below the synovial and endothelial channel layers, which covers the first synovial channel 61, the immune cell channel 9, and the second synovial channel 62 from the bottom.

[0077] Furthermore, the underlying layer is provided with a photoelectric module array 7, which is used to monitor the cells in the first synovial channel 61, the immune cell channel 9 and the second synovial channel 61, as well as physicochemical properties such as oxygen content and pH value.

[0078] The photoelectric module can be either contact or non-contact. When it is contact, its probe extends into each synovial channel and immune cell channel 9.

[0079] This design is based on the fact that existing synovial organ-on-a-chip systems typically require external observation equipment to detect changes in the chip's internal physicochemical properties, cell migration, and other parameters. This often necessitates terminating the continuous culture process and wastes a significant amount of time. This organ-on-a-chip integrates photoelectric modules under the synovial and immune cell channels 9, enabling the monitoring of fundamental data such as oxygen content and pH values ​​during continuous culture. It offers advantages such as high throughput, low invasiveness, and long-term stability, making it well-suited for use with microfluidic chips.

[0080] Furthermore, two sets of first fluid exchange holes 131 are symmetrically arranged at both ends of the top layer; a set of first fluid exchange pools are symmetrically arranged at both ends of the cartilage cavity 2 of the cartilage layer; the first fluid exchange pools are connected to the cartilage cavity 2 and correspond one-to-one with a set of first fluid exchange holes 131, and are used to exchange fluid for the cartilage cavity 2 from the top layer by gravity. The cartilage cavity 2 of the cartilage layer is symmetrically provided with a set of second fluid exchange holes 132 at both ends; the synovial cavity 4 of the joint synovial fluid layer is symmetrically provided with a set of second fluid exchange pools at both ends; the second fluid exchange pools are connected to the synovial cavity 4 and correspond one-to-one with a set of second fluid exchange holes 132 and another set of first fluid exchange holes 131, forming two vertical channels for exchanging fluid in the synovial cavity 4 from the top layer by gravity or microfluidic means.

[0081] Furthermore, the diameter or width of the first synovial channel 61 and the second synovial channel 62 ranges from 400 to 600 micrometers, preferably 500 micrometers; the diameter or width of the immune cell channel 9 ranges from 200 to 300 micrometers, preferably 250 micrometers.

[0082] Furthermore, it also includes a first microfluidic device, the output port and return port of which are connected to the inlet 111 and outlet of the first synovial channel, respectively, to force the fibrin gel (or synovial fluid) containing fibroblasts from the synovium to circulate through the first synovial channel 61.

[0083] Furthermore, it also includes a second microfluidic device, the output port and return port of which are connected to the inlet 112 and outlet of the second synovial channel, respectively, to force the fibrin gel (or synovial fluid) containing fibroblasts from the synovium to circulate through the second synovial channel 62.

[0084] Furthermore, it also includes a third microfluidic device, the output port and return port of which are connected to the inlet 12 and outlet of the immune cell channel, respectively, for injecting immune cells into the immune cell channel 9.

[0085] Furthermore, it also includes a fourth microfluidic device, the output port and return port of which are respectively connected to the vertical channels at both ends of the synovial cavity (i.e., the first fluid exchange holes 131 corresponding to the vertical channels), forcing the joint synovial fluid to circulate through the synovial cavity.

[0086] Preferably, when the immune cell channel 9 is pre-endothelialized, human umbilical vein endothelial cells are used, and the culture medium is endothelial cell growth medium 2 (EGM-2).

[0087] Preferably, the immune cells injected into the immune cell channel 9 are human primary mononuclear cells.

[0088] This invention provides a biomimetic 3D synovial cartilage organ-on-a-chip, its preparation method, and its application. By integrating mechanical stimulation into the organ-on-a-chip, it can reproduce the periodic compression experienced by the human body during walking / activity, thereby more realistically simulating the mechanical-biochemical coupling of the cartilage-synovium-bone interface and improving the similarity of in vitro models. It can promote the formation of (perfusion / mature) cartilage-like matrix, improve nutritional / metabolic homeostasis and mechanical properties during long-term culture, and thus facilitate subsequent pharmacodynamic evaluation. It can be used as a "stress-triggered pathological stimulus" to simulate overload injury or chronic low-dose injury, thereby establishing a more clinically relevant pathological model on the organ-on-a-chip (e.g., mechanically induced inflammation and matrix degradation), which is particularly important for screening anti-inflammatory or anti-degradation candidate drugs.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A 3D synovial cartilage organ-on-a-chip with a biomimetic structure, characterized in that, Includes the main body; The main body comprises, in sequence, a top layer, a cartilage layer, a synovial fluid layer, a synovium, and an endothelial channel layer; The cartilage layer contains a cartilage cavity for accommodating articular cartilage cells. The joint synovial fluid layer is provided with a synovial fluid cavity for containing the joint synovial fluid; The synovial membrane and endothelial channel layer contain parallel synovial channels and immune cell channels; a permeable zone is provided between the synovial channels and the immune cell channels; A pressure chamber is provided inside the top layer, and an elastic membrane is provided on one side of the cartilage cavity within the pressure chamber; the outer surface of the elastic membrane is in contact with the articular cartilage cells within the cartilage cavity.

2. The organ-on-a-chip according to claim 1, characterized in that, The organ-on-a-chip also includes a working medium control system, which is connected to the pressure chamber and is used to input or output working medium into the pressure chamber, control the pressure changes in the pressure chamber, force the elastic membrane to bulge or contract, and thus apply dynamically changing pressure to the articular cartilage cells.

3. The organ-on-a-chip according to claim 1, characterized in that, The elastic film is a PDMS film made of polydimethylsiloxane.

4. The organ-on-a-chip according to claim 1, characterized in that, The thickness of the elastic film ranges from 20 to 30 micrometers.

5. The organ-on-a-chip according to claim 2, characterized in that, The working medium is compressed air or liquid; The working medium control system includes an air pump or a hydraulic pump, which is connected to the inlet of the pressure chamber via a delivery pipeline; the outlet of the pressure chamber is connected to a recovery pipeline; and control valves are installed on the delivery pipeline and / or the recovery pipeline to control the delivery speed and pressure value of the working medium.

6. The organ-on-a-chip according to claim 1, characterized in that, The cartilage cavity is filled with fibrin gel containing articular chondrocytes.

7. The organ-on-a-chip according to claim 1, characterized in that, The cartilage cavity and the synovial cavity are stacked one on top of the other, with a first partition in the middle. The first partition has first through holes evenly distributed on it, connecting the cartilage cavity and the synovial cavity.

8. The organ-on-a-chip according to claim 7, characterized in that, The diameter of the first via is 80-150 micrometers.

9. The organ-on-a-chip according to claim 1, characterized in that, On the horizontal projection plane, the cartilage cavity and the synovial cavity overlap at their edges, meaning that the cartilage cavity and the synovial cavity have the same shape and size.

10. The organ-on-a-chip according to claim 1, characterized in that, On the horizontal projection plane, the cartilage cavity and the synovial cavity are rectangular in shape.

11. The organ-on-a-chip according to claim 1, characterized in that, The synovial channel is filled with fibrin gel derived from fibroblasts of the synovium. The synovial channel includes a first synovial channel and a second synovial channel; The first synovial channel, the immune cell channel, and the second synovial channel are arranged side by side in sequence; The immune cell channel is used to deliver immune cells.

12. The organ-on-a-chip according to claim 1, characterized in that, The permeation zone includes trapezoidal columns evenly spaced along the channel axis; a third through-hole is formed between adjacent trapezoidal columns to allow monocytes / macrophages to pass through.

13. The organ-on-a-chip according to claim 12, characterized in that, In the cross-section of the trapezoidal column: the height of the trapezoid is 100 micrometers; the side on the immune cell channel side is the upper base, and the width of the upper base ranges from 50 to 100 micrometers; the side on the synovial channel side is the lower base, and the width of the lower base ranges from 120 to 200 micrometers; the distance between adjacent upper bases can be 100 micrometers.

14. The organ-on-a-chip according to claim 11, characterized in that, A second partition is provided at the bottom of the synovial cavity in the joint synovial fluid layer to separate the synovial cavity from the first synovial channel, the immune cell channel and the second synovial channel below. The second partition plate has a second through hole only at the position of the first synovial channel, which is used to connect the synovial cavity and the first synovial channel.

15. The organ-on-a-chip according to claim 14, characterized in that, The aperture of the second via ranges from 80 to 150 micrometers; the center-to-center distance between two adjacent second vias ranges from 160 to 300 micrometers.

16. The organ-on-a-chip according to claim 11, characterized in that, The diameter range of the first and second synovial channels is 400-600 micrometers.

17. The organ-on-a-chip according to claim 11, characterized in that, Below the synovial membrane and endothelial channel layer, there is a bottom layer that covers the first synovial channel, the immune cell channel and the second synovial channel from the bottom.

18. The organ-on-a-chip according to claim 17, characterized in that, The underlying layer is equipped with an array of photoelectric modules for monitoring cells in the first synovial channel, immune cell channel, and / or second synovial channel, as well as physicochemical properties such as oxygen content and pH value.

19. The organ-on-a-chip according to claim 1, characterized in that, Two sets of first fluid exchange holes are symmetrically arranged at both ends of the top layer; a set of first fluid exchange pools are symmetrically arranged at both ends of the cartilage cavity of the cartilage layer; the first fluid exchange pools are connected to the cartilage cavity and correspond one-to-one with a set of first fluid exchange holes, and are used to exchange fluid for the cartilage cavity from the top layer by gravity. The cartilage cavity of the cartilage layer is symmetrically provided with a set of second fluid exchange holes at both ends; the synovial cavity of the joint synovial fluid layer is symmetrically provided with a set of second fluid exchange pools at both ends; the second fluid exchange pools are connected to the synovial cavity and correspond one-to-one with a set of second fluid exchange holes and another set of first fluid exchange holes, forming two vertical channels for exchanging fluid in the synovial cavity from the top layer by gravity or microfluidic means.

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