Microfluidic device for cultivating a tissue section

Abstract

The invention relates to a microfluidic device (100) for cultivating a tissue section (4). Said device has a first layer (1) with two main surfaces and a recess (10) for receiving the tissue section (4), which recess is open at least to one side, and at least one further layer (2, 3) which is arranged on the first layer (1) and has a network of microfluidic channels (21, 31) at least in the region (20, 30) of the recess (10). The microfluidic channels (21, 31) have openings (22, 32) by means of which they are in fluidic contact with the recess (10) in the first layer (1).

Description

[0001] Description

[0002] title

[0003] Microfluidic device for culturing a tissue section

[0004] The present invention relates to a microfluidic device for culturing a tissue section, in particular a tumor tissue section, for example, for drug testing. Furthermore, the present invention relates to a method for culturing a tissue section.

[0005] State of the art

[0006] Cancer patients with solid tumors unfortunately respond differently to drug therapy. The main reasons for this are the individual variability and heterogeneity of the tumors, as well as the complexity of the tumor microenvironment. There is a great need for increasing personalized cancer treatment, which, among other things, takes into account the cellular characteristics of the individual patient in order to derive an individually optimized therapy. Furthermore, there is a great need for a reliable in vitro tumor model that adequately reflects the in vivo situation and can be used for the development and preclinical testing of new antitumor agents.

[0007] During a biopsy or surgery, for example, cancer tissue can be removed from a patient. The cancer tissue is then cultured and used for in vitro testing of cancer drugs and to investigate individual drug effects. In vitro testing requires a suitable cell-based tumor model, which can be obtained from tissue samples from cancer patients and reflects key aspects of complex in vivo tumor biology. Thin tissue sections are prepared from the removed tumor sample. These tumor tissue sections are particularly suitable for use as tumor models due to the preservation of in vivo tissue heterogeneity with various cell types and the preserved tumor microenvironment. Various methods have been developed for culturing tumor tissue sections, but these only allow for a limited cultivation time.After a few days, the viability of the cells in the tissue section decreases significantly, and the cells die. Furthermore, the cultivation methods and systems are not able to adequately replicate physiologically relevant in vivo conditions.

[0008] Today, viable tumor tissue sections are cultured either floating in a suitable medium or lying on a filter. The most commonly used culture system is a tissue culture insert for multiwell plates (Millipore filters). In this system, the tissue sections are cultured at the air-liquid interface, thus achieving a higher oxygen supply.

[0009] In addition, cultivation approaches exist that implement a fluidic supply of culture medium to the tissue sections instead of static cultivation. For example, the so-called Perfusion Air Culture (PAC) system with adjustable medium or drug supply was developed, which is disclosed in WO 2019 / 029947 A1.

[0010] The limited cultivation time of tissue sections is mainly due to the fact that the tumor tissue removed during a biopsy or surgery is separated from the blood supply. By cutting the tumor tissue, its three-dimensional tissue structure is destroyed and the functionality of the blood and lymph vessels is lost.

[0011] Disclosure of the invention

[0012] A microfluidic device for cultivating a tissue section is proposed. In particular, the tissue section is a tumor tissue section. The microfluidic device has several layers, which can also be interpreted as different microfluidic components. A first layer has a recess in which a tissue section can be received. The recess can generally have any shape, but a circular shape is suitable due to its ease of manufacture. Alternatively, the shape of the recess can be adapted to the tissue section and, for example, trace its outer contour. The first layer is open on at least one side, in particular on one of the main surfaces, i.e. it has a recess on at least one side. The main surfaces here are referred to as the (typically two) side surfaces with the largest extent.The microfluidic device also has at least one further, for example second, layer arranged on one of the main surfaces of the first layer.

[0013] In an area of ​​the second layer that overlaps with the recess of the first layer when the first and second layers are joined together, the second layer has a network of microfluidic channels. The microfluidic network has an irregular structure, modeled on a vascular system around a tumor. In particular, the characteristic blood vessel systems of tumor tissue are replicated by the network of microfluidic channels. In tumors, strong cell growth and the expression of angiogenic factors lead to the development of blood vessel networks that differ significantly from normal vasculature. These blood vessels are incompletely formed, hyperpermeable, and have non-uniform diameters as well as irregular structures and shapes, such as bulges, shunts, unilaterally closed vessels, and the like. Similarly, the lymphatic vessels are dilated and more permeable.As a whole, the vascular system characteristic of tumors has a decisive impact on the local distribution of oxygen and nutrients, the development of the tumor and the tumor microenvironment, and the delivery of drugs to the tumor cells. The microfluidic channels of the network can mimic arterial, venous, and, if necessary, lymphatic capillaries. The microfluidic channels exhibit non-uniform diameters and shapes, forming, for example, bulges, shunts, and / or unilaterally closed vessels. In this way, an anomalous tumor vasculature is recreated in vitro.

[0014] In the area of ​​the recess in the first layer, the channels of the second layer also have openings—also referred to as pores—to the first layer. Through these openings (or pores), the microfluidic channels of the second layer are in fluidic contact with the recess in the first layer and thus with the tissue section that can be placed in the recess, allowing fluids to be supplied and / or removed. The diameters of the openings can be suitably selected and are advantageously between 1 μm and 100 μm.

[0015] The microfluidic channels ensure a defined supply of nutrients and oxygen to the tissue section, as well as, for example, the removal of metabolic products. A culture medium with a predefined nutrient composition and oxygen concentration is fluidically supplied to the tissue section. The culture medium flowing past the tissue section absorbs the cellular metabolic products produced therein and is then removed via one or more microfluidic channels. This achieves dynamic perfusion of the tissue section to be cultured.

[0016] In addition, a pharmacological drug solution of a defined volume and concentration can be dosed into the tissue section via the microfluidic channels. This can be used in drug testing to ensure precise delivery of drug solutions to the tissue section.

[0017] In tumors, the balance between blood supply and blood drainage through the blood vessels, as well as the drainage of tissue fluid through the lymphatic vessels, is significantly disturbed. Increased interstitial fluid pressure (hereinafter also referred to as fluidic pressure) is caused by the leakage of blood plasma from the hyperpermeable tumor blood vessels and by inadequate lymphatic drainage. Leaky vessels combined with the disrupted drainage system lead to high fluidic pressure. This causes, among other things, edema and flow-induced shear stresses, and the delivery of medication is impaired. The fluidic pressure acting on the tissue section and the cells contained therein can be realized in vitro by building up a pressure difference between the microfluidic inlets and outlets of at least one microfluidic network. Fluidic pressure values ​​of, for example, approx.1 kPa (7.5 mmHg) as in brain tumors and up to 5 kPa (37 mmHg) as in kidney carcinomas.

[0018] Preferably, a pumping mechanism, such as a syringe pump or a peristaltic pump, which is connected to the microfluidic channels, can be provided for the supply and removal of the fluid. The pumping mechanism can be set with a suitably selectable flow rate.

[0019] Additionally, the first layer can have at least one microfluidic channel connected to the recess. The at least one microfluidic channel replicates the lymphatic system that surrounded the tissue section in vivo in vitro and serves to drain fluids and metabolic products. Exactly one microfluidic channel with a suitable diameter can be provided for drainage. Alternatively, multiple microfluidic channels can be provided, which can, in particular, form a network with complex structures and shapes. Thus, multiple and irregularly arranged lymphatic vessels can be mimicked.

[0020] In general, the additional, second layer may already be sufficient if the recess in the first layer is closed off on one side, either by the first layer itself or by a simple additional layer or component. In this case, the supply and removal are realized via the same microfluidic network in the second layer, optionally together with the at least one microfluidic channel in the first layer. Preferably, the microfluidic device has a second and a third layer, which are each arranged on the main surfaces of the first layer. For example, the second layer is arranged on one main surface of the first layer and the third layer is arranged on the other main surface of the first layer, which are preferably opposite one another. The supply and removal of fluids can take place in both microfluidic networks of the second and third layers.This means that the tissue section is supplied from multiple sides. Alternatively, the supply and removal can take place separately in the layers. The microfluidic networks can be identical in both layers. This leads to easier production of the layers and an evenly distributed supply to the tissue section. Alternatively, the microfluidic networks of the two layers can be different from one another. This allows the supply and removal of culture medium, oxygen and, if necessary, drug solution to be implemented differently on both sides of the tissue section. In the event that a second and a third layer are arranged on the opposite main surfaces of the first layer, the recess in the first layer is open on both sides. This is easily achieved by drilling a through-hole through the first layer, which then serves as a recess.

[0021] The thickness of the first layer is preferably selected to be smaller than the thickness of the tissue section. The thickness of the first layer is preferably in the range of 150 μm to 400 μm. Thus, tissue sections which, for example, have a thickness greater than the thickness of the first layer are clamped between the second layer and in particular between the second and third layers. This clamping exerts mechanical pressure on the tissue layer. This mimics the mechanical stresses and pressures which arise inside and outside the tumor when proliferating and moving tumor cells press on the surrounding tissue and stretch it. The mechanical pressure can reach values ​​of, for example, 100 Pa in brain tumors and 10 kPa in pancreatic carcinomas. The mechanical pressure can compress blood and lymph vessels in and around the tumors, which affects blood flow and the supply of oxygen, medications, and immune cells.In addition, the resulting mechanical forces at the tissue and cellular level activate signaling pathways that promote tumorigenesis, proliferation, and invasiveness of cancer cells, as well as induce treatment resistance. Alternatively, the thickness of the first layer can be chosen to be equal to or greater than the thickness of the tissue section. In this case, no mechanical pressure is exerted on the tissue layer.

[0022] Furthermore, a method for cultivating a tissue section using the device described above is proposed. The shape of the tissue section is selected so that it corresponds to the general shape of the recess. In the case of a circular recess, the tissue section is generated as circular as possible. The shape of the tissue section does not have to correspond exactly to the shape of the recess and can, for example, have indentations and / or bulges that deviate from the ideal shape of the recess. In order for the tissue section to be inserted into the recess, the cross-sectional area of ​​the tissue section should correspond at most to the cross-sectional area of ​​the recess. Alternatively or additionally, the longest side or the longest radius of the tissue section should correspond at most to the longest side or the longest radius of the recess.For the preferred case where mechanical pressure is to be exerted on the tissue section, the tissue section is generated with a thickness greater than the thickness of the first layer. The thickness of the first layer can be selected in advance so that it is smaller than the thickness of the expected tissue section. The thickness of the tissue layer is preferably in the range of 150 μm to 400 μm. When joined, the at least one second layer presses against the tissue section and clamps it in place.

[0023] The tissue section is placed in the recess of the first layer. The first layer is then covered with at least one second layer. The second layer is positioned so that the recess of the first layer is flush with the area of ​​the second layer where the openings for the microfluidic channels are provided. The second layer and the first layer are bonded, for example, by pressing.

[0024] Finally, fluids are supplied and removed through the microfluidic channels in the second layer. The fluids can be a culture medium with a predetermined concentration of nutrients and oxygen, as described above. For drug testing, at least one drug solution with a predetermined concentration can also be supplied.

[0025] In the preferred case that the microfluidic device further comprises a third layer, before placing the tissue section, one of the further layers, for example the second layer, is arranged below the first layer and the first layer is then placed on top. The second layer is arranged such that the recess in the first layer is flush with the area of ​​the second layer in which the openings for the microfluidic channels are provided. The tissue section is then placed in the recess in the first layer and, for example, placed on the second layer. The tissue section thus comes into contact with the area of ​​the second layer in which the openings for the microfluidic channels are provided. Finally, a further layer, for example a third layer, is placed on top of the first layer.As already described above in connection with the at least one layer, the third layer is arranged such that the recess of the first layer is flush with the area of ​​the third layer in which the openings for the microfluidic channels are provided. Finally, the layers can be joined together, for example, by pressing them together.

[0026] In this case, either the supply and removal of the fluids can take place in the fluidic networks of each of the two layers or the fluids are supplied via the fluidic network of one layer, for example the second layer, and removed via the fluidic network of the other layer, for example the third layer.

[0027] If, as described above, at least one microfluidic channel is provided in the first layer that is connected to the recess, it can be provided to drain fluid from the recess and thus from the tissue section via the at least one microfluidic channel in the first layer. Metabolic products can also be drained away with the fluid. The at least one microfluidic channel simulates a lymphatic vessel of the tissue, in particular a tumor, in vitro.

[0028] Short description of the drawings

[0029] Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

[0030] Figure 1 shows an exploded view of an embodiment of the microfluidic device according to the invention.

[0031] Figure 2 shows a plan view of a first layer of the microfluidic device of Figure 1 .

[0032] Figure 3 shows a top view of a second layer of the microfluidic device of Figure 1

[0033] Figures 4a, b each show a cross-section of the microfluidic device from Figure 1 in the separated state (Figure 4a) and in the assembled state (Figure 4b). Figures 5a-d each show a cross-section through the second layer at different stages of the manufacturing process.

[0034] Figure 6 shows a flow diagram of an embodiment of the method according to the invention.

[0035] Embodiments of the invention

[0036] Figure 1 shows an exploded view of a microfluidic device for cultivating a tissue section 4. The microfluidic device has a first layer 1, a second layer 2, which is arranged below the first layer 1, and a third layer 3, which is arranged above the first layer 1. The first layer 1 has a recess 10 designed as a circular through-opening, in which the tissue section 4 is received. The first layer 1 has a thickness di that is smaller than the thickness d4 of the tissue section 4. In further embodiments not shown, the thickness di of the first layer 1 is the same size as or greater than the thickness d4 of the tissue section d4. A microfluidic channel 11 is connected to the recess 10, which functionally replicates a lymphatic vessel of the tissue section 4, in particular of a solid tumor.The second layer 2 and the third layer 3 are identical in this embodiment. The following description refers to the second layer 2, but can be adopted for the third layer 3 (unless an explicit distinction is made between the layers). The second layer 2 has a network of microfluidic channels 21, which in a region 20 simulate irregular structures and shapes of the blood vessels of the tissue section 4, in particular characteristic tumor blood vessels. Likewise, the third layer 3 has a network of microfluidic channels 31, which in a region 30 also simulate the irregular structures and shapes of the blood vessels of the tissue section 4, in particular characteristic tumor blood vessels. In this embodiment, the two microfluidic networks of the second layer 2 and the third layer 3, as well as their microfluidic channels 21 and 31, are identical.The two regions 20 and 30 are arranged below and above the recess 10 of the first layer 1, respectively, flush with the latter and correspond to the shape of the recess 10, i.e., they have a circular shape with the same radius. In further embodiments not shown, the second layer 2 and the third layer 3, or their microfluidic networks or the microfluidic channels 21 and 31, can be designed differently. In this case, the supply and discharge of fluids can also be realized in different layers 2, 3.

[0037] Figure 2 shows a plan view of the first layer 1. As already described, the first layer 1 has a recess 10 designed as a through-opening, which serves to receive the tissue section 4. The shape, radius and position of the recess 10 correspond to the regions 20 and 30 of the second layer 2 and the third layer 3. The through-opening is circular in this exemplary embodiment. Alternatively, other shapes can be realized, which are adapted, for example, to the outer contours of the tissue section 4. As already described, a microfluidic channel 11 is connected to the recess 10, which functionally simulates a lymphatic vessel of the tissue section 4, in particular of a solid tumor. In this embodiment, exactly one microfluidic channel 11 is provided. In further embodiments, several draining channels can also be provided.Through this microfluidic channel 11, fluid is selectively discharged from the recess 10. In this embodiment, the top and bottom sides of the microfluidic channel 11 are formed by the layers 2 and 3 positioned above and below, respectively. The microfluidic channel 11 has a microfluidic port on the side of the first layer 1, through which the fluid is discharged from the microfluidic device. A pump unit, such as a syringe pump or a peristaltic pump, can be connected to the microfluidic port.

[0038] Figure 3 shows a plan view of the second layer 2. The third layer 3 is identical in the present embodiment, so that the following description can be applied to the third layer 3. The second layer 2 has microfluidic channels 21 beneath its surfaces. On the left and right sides, the second layer 2 each has a microfluidic connection. In this exemplary embodiment, both the supply and the removal of fluids are realized in the second layer 2 (and correspondingly also in the third layer 3). As shown by the arrows, a fluid can be supplied via the left connection and removed via the right connection. For this purpose, the microfluidic connections can be connected to pump units, such as a syringe pump or a peristaltic pump.

[0039] In a region 20 that corresponds in shape, diameter, and position to the recess 10 of the first layer 1, the microfluidic channels 21 form a network that mimics the irregular structures and shapes of in vivo blood vessels in the tissue section, in particular the characteristic tumor blood vessels in solid tumors. The geometric design of the microfluidic channels 21 is irregular, and they can have different and non-uniform diameters, bulges, constrictions, vessels ending on one side, shunts, and / or the like. The diameter of the microfluidic channels 21 is advantageously between 5 μm and 500 μm. In the aforementioned region 20, the microfluidic channels 21 also have small openings 22 (see Figure 4) that are open toward the first layer 1. Thus, a fluid can escape from the microfluidic channels 21 of the second layer 2 into the recess 10 of the first layer 1.Likewise, a fluid can exit from the recess 10 into the microfluidic channels 21 of the second layer 2. Outside of the region 20, the microfluidic channels 21 can also be regular and orderly. Thus, in Figure 3, the microfluidic channels 21 to the left of the region 20 form an orderly, tree-like branched structure. On the left side, as described above, is the microfluidic supply port. This makes it possible to specifically divide a microfluidic channel 21 and thus guide the fluid into the region 20 via multiple channels 21. To the right of the region 20, the microfluidic channels 21 open into a single microfluidic channel, which leads to the microfluidic discharge port on the right side. In other embodiments, further suitable channel structures can be provided within the second layer 2.

[0040] Figures 4a and b each show a cross-section of the microfluidic device. In Figure 4a, layers 1, 2, and 3 are shown separated from one another. Figure 4b shows the microfluidic device in the assembled state, in which layers 1, 2, and 3 are connected to one another, in particular by pressing. The second layer 2 has openings 22 in the region 20 (see Figures 1 and 3), starting from the microfluidic channels 21 in the direction of the first layer 1. Likewise, the third layer 3 has openings 32 in the region 30, starting from the microfluidic channels 31 in the direction of the first layer 1. The openings 22 can also be interpreted as pores. Fluids can pass from the microfluidic channels 21, 31 through the openings 22, 23 into the recess 10 of the first layer 1 and thus to the tissue section 4.Likewise, fluids can flow from the recess 10 through the openings 22, 23 into the microfluidic channels 21, 31 and then be transported away. This enables the microfluidic supply of nutrients and oxygen to the tissue section, the removal of metabolic products, and the administration of medication. The geometric configuration—i.e., the size, shape, and spacing of the openings 22, 32—can be suitably selected to locally achieve greater or lesser permeability of the microfluidic channels 21, 31 for the fluids. The diameters of the circular openings 22, 32 here are, for example, 50 μm.

[0041] When generating the tissue section 4, in particular a tumor tissue section, the thickness d4 of the tissue section 4 is selected to be greater than the thickness di of the first layer 1. The thickness di of the first layer 1 can be selected to suit the application during production of the microfluidic device. The thickness d4 of the tissue section 4 can be determined, for example, by a measurement. In this example, the tissue section 4 is generated with a thickness d4 of 160 pm. The thickness di of the first layer 1 is, for example, 140 pm. In the separated state in Figure 4a, the thickness di of the first layer 1 is thus less than the tissue section thickness d4. When joining the layers 1, 2 and 3, the tissue section 4 is mechanically clamped in a defined manner, as shown in Figure 4b.

[0042] An adjustable mechanical pressure is thus applied to the tissue section 4, simulating the in vivo situation, particularly in solid tumors. The strength of the adjustable mechanical pressure depends on the difference between the tissue section thickness d4 and the thickness di of the first layer 1. This can be determined, for example, through previously conducted experimental tests and stored, for example, in a characteristic curve. In an alternative embodiment of the microfluidic device, the thickness di of the first layer 1 is greater than the thickness d4 of the tissue section 4, so that cultivation and drug testing can be realized without mechanical pressure on the tissue section 4.In the assembled state in Figure 4b, a pressure difference is built up between the inlet connections of the second layer 2 and the third layer 3 and the outlet connections of the second layer 2 and the third layer 3 as well as the microfluidic channel 11 of the first layer 1. Thus, a defined fluidic pressure can be set on the cultured tissue section 4.

[0043] In other embodiments, the second layer 2 and the third layer 3 are configured differently. The supply of the culture medium, the oxygen, and optionally the drug solution can be effected via the microfluidic channels 21 of the second layer 2. The past culture medium and the absorbed cellular metabolic products are then removed on the other side via the microfluidic channels 31 of the third layer 3. The separate supply and removal ensure that only the culture medium that has flowed past the tissue section 4 is removed.

[0044] Figures 5a-d show various stages of the manufacturing process for the second layer 2 and the microfluidic channel 21. The manufacturing process for the third layer 3 and the microfluidic channel 31 is identical, so that the following description can be adopted. In Figure 5a, a substrate for the second layer 2 is initially provided. Materials known per se can be used for this purpose. As shown in Figure 5b, a microfluidic channel 21 is formed in this substrate 23 using methods known per se. In Figure 5c, the microfluidic channel 21 is covered with a lid 24. Preferably, the same material is used for the lid 24 as for the substrate 23. Finally, in the region 20 (see Figures 1 and 3), the above-described openings 22 are incorporated into the lid 24, as shown in Figure 5d.

[0045] Figure 6 shows a flow diagram of an embodiment of the method according to the invention. Initially, layers 1, 2 and 3 are produced or provided 100. The first layer 1 is produced by drilling a through-hole into a substrate with a thickness d 1 , which acts as a recess 10. Subsequently, a microfluidic channel 11 is formed between the recess 10 and one side of the first layer 1. The second layer 2 and the third layer 3 are produced as described above in connection with Figure 5. To assemble the microfluidic device, the first layer 1 is placed 101 onto the second layer 2. The region 20 of the second layer 2 is arranged flush below the recess 1.

[0046] The tissue section 4 has a shape that corresponds to the recess 10, with a diameter that is equal to or smaller than the diameter of the recess 10 and with a thickness d4 that is smaller here than the thickness di of the first layer 1. The tissue section 4 is then introduced 104 into the recess 10 of the first layer 1. For this purpose, it is placed, for example, on the second layer 2. The recess 10 and the second layer 2 as the base together form a cavity. Finally, the third layer 3 is placed 105 on the first layer 1 so that the cavity is closed. The region 30 of the third layer 3 is arranged flush above the recess 10. The three layers 1, 2, 3 are then mechanically connected 106 and fastened by pressing. Alternatively, the first layer 1 can be placed on the third layer 3 in step 101. The recess 10 and the third layer 3 as the base together form a cavity.In step 105, the second layer 2 is then placed on the first layer 1.

[0047] To cultivate the tissue section 4, a supply 107 of fluids is provided. The fluids are introduced into the recess 10 of the first layer via the microfluidic channels 21, 31 of the second layer 2 and the third layer 3, and thus supplied to the tissue section 4. Furthermore, the supplied fluids are discharged via the microfluidic channels 21, 31 of the second layer 2 and the third layer 3, as well as via the microfluidic channel 11 of the first layer 1. For this purpose, a pump system is controlled at the inlets and outlets of the microfluidic channels 11, 21, 31.

Claims

Claims 1 . Microfluidic device for cultivating a tissue section (4), comprising a first layer (1) with two main surfaces and with a recess (10) for receiving the tissue section (4), which recess is open at least on one side, and at least one further layer (2, 3) which is arranged on a main surface of the first layer (1) and has a network of microfluidic channels (21, 31) at least in the region (20, 30) of the recess (10), wherein the microfluidic channels (21, 31) have openings (22, 32) with which they are in fluidic contact with the recess (10) in the first layer (1).

2. Microfluidic device according to claim 1, characterized in that the first layer (1) has at least one microfluidic channel (11) which is connected to the recess (10) 3. Microfluidic device according to claim 1 or 2, characterized in that the diameter of the openings (22, 32) of the microfluidic channels (21, 31) of the at least one further layer (2, 3) is in the range of 1 pm to 100 pm 4. Microfluidic device according to one of the preceding claims, characterized in that the further layer is a second layer (2) and that the device has, in addition to the second layer (2), a third layer (3) which is arranged on the other main surface of the first layer (1) and has, at least in the region (30) of the recess (10), a network of microfluidic channels (31), wherein the microfluidic channels (31) have openings (32) with which they are in fluidic contact with the recess (10) in the first layer (1).

5. Microfluidic device according to one of the preceding claims, characterized in that the recess (10) is a through hole is.

6. Microfluidic device according to one of the preceding claims, characterized in that the thickness (di) of the first layer (1) is in the range from 150 pm to 400 pm.

7. A method for cultivating a tissue section (4) with a device according to one of claims 1 to 6, comprising the following steps: - placing (104) a tissue section (4) in the recess (10) of the first layer (1); - covering (105) at least one main surface of the first layer (1) with at least one further layer (2, 3), wherein the recess (10) of the first layer (1) is arranged flush with the region (20, 30) of the at least one further layer (2, 3) in which openings (22, 32) are provided in the microfluidic channels (21, 31); - Supply and / or removal (107) of fluids through the microfluidic channels (21, 31) in the at least one further layer (2, 3).

8. Method according to claim 7, characterized in that the fluids contain nutrients, oxygen and / or at least one medicament solution.

9. Method according to claim 7 or 8, characterized in that the first layer (1) has a thickness (di) which is smaller than a thickness (di) of the tissue section (4).

10. Method according to one of claims 7 to 9, characterized in that a second layer (2) is arranged (101) on a main surface of the first layer (1), wherein the recess (10) of the first layer (1) is arranged above the region (20) of the second layer (2) in which openings (22) in the microfluidic channels (21) are provided, the tissue section (4) is placed (104) in the recess (10) of the first layer and then the third layer (3) is arranged on the other main surface of the first layer (1), wherein the recess (10) of the first layer (1) is arranged below the region (30) of the third layer (3) in which Openings (32) for the microfluidic channels (31) are provided.

11. Method according to one of claims 7 to 10, characterized in that a fluid is discharged through at least one microfluidic channel (11) in the first layer (1).

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