WO2025061631A1 - Microsystem component - Google Patents

Abstract

The invention relates to a microsystem component (1) comprising a substrate (2, 3) which has a receiving chamber (9), an insertion opening (7) which leads to the receiving chamber (9), and a perfusion channel (4). The perfusion channel (4) is communicatively connected to the receiving chamber (9) and has an inlet (5) and an outlet (6). The receiving chamber (9) is arranged in the perfusion channel (4) and is delimited by a perforated wall (10). The insertion opening (7) opens into the receiving chamber (9) delimited by the perforated wall (10), and the perforated wall (10) surrounds the insertion opening (7), said perforated wall (10) extending from the perfusion channel (4) wall region which adjoins the insertion opening (7) into the perfusion channel (4) and to the wall region lying opposite the insertion opening (7), and the receiving chamber (9) delimited by the perforated wall (10) is spaced from at least one adjacent inner wall of the perfusion channel (4). The cross-section of the perfusion channel (4) is not completely taken up by the receiving chamber (9) delimited by the perforated wall (10) in the region of the receiving chamber (9) so that a fluid flowing from the inlet (5) to the outlet (6) in the direction of the longitudinal extension of the perfusion channel (4) flows against the perforated wall (10), wherein a sub-flow of a fluid flowing through the perfusion channel (4) flows through the receiving chamber (9), and another bypass sub-flow flows past the receiving chamber (9).

Description

Microsystem component

Description:

The invention relates to a microsystem component comprising a substrate having a receiving chamber, an insertion opening leading to the receiving chamber and a perfusion channel, wherein the perfusion channel is communicatively connected to the receiving chamber and has an inlet and an outlet, and wherein the receiving chamber is arranged in the perfusion channel and is delimited by a perforated wall.

The analysis of samples, such as cell cultures, can be performed using microfluidic microsystem components. These are provided as microfluidic chips, which enable efficient, automated in vitro testing with very small sample volumes. Compared to in vitro assays in the well format, the smaller analysis area on the chip requires less sample input, and the cell culture can be controlled by supplying nutrients and influenced by introducing active substances, with the effects being studyable in real time.

Trujillo-de Santiago, G. et al.: “The Tumor-on-Chip: Recent Advances in the Development of Microfluidic Systems to Recapitulate the Physiology of Solid Tumors”, in: Materials 2019, 12, 2945 gives an overview of existing microfluidic microsystem devices and their flow dynamics. CA 3 031 439 A1 discloses a microfluidic organ-on-chip device with microchannels, adjacent to which a receiving chamber defined by a membrane, a columnar structure, or matrix surfaces is arranged. The receiving chamber can be arranged adjacent to two parallel microchannels. Convective fluid exchange, or perfusion of a cell culture, is enforced by the arrangement of the fluid inlets and the perfusion chamber, whereby pressure surges and uneven flow conditions can occur.

Toh, Y.-C. et al.: "A microfluidic 3D hepatocyte chip for drug toxicity testing", in: Lab Chip, 2009, 9, 2026-2035 discloses a microsystem component with microfluidic channels that are connected in parallel to a common inlet and outlet. Cell culture chambers are defined within the channels by microposts, which are accessible via an insertion opening for introducing the cell culture. The cell culture chambers extend over the length of the perfusion channels, whereby the fluid conveyed through the perfusion channels, which may contain, for example, nutrients and/or active ingredients, flows past the cell culture chamber, and the nutrients and/or active ingredients can only penetrate into the cell culture chamber by diffusion.

The object of the present invention is to provide a microsystem component which is improved, in particular with regard to the pressure and flow conditions in the receiving chamber.

The object is achieved with the microsystem component having the features of claim 1. Advantageous embodiments are described in the subclaims.

It is proposed that the insertion opening opens into the receiving chamber delimited by the perforated wall and the perforated wall surrounds the insertion opening, wherein the perforated wall extends from the wall region of the perfusion channel adjacent to the insertion opening into the perfusion channel to the wall region opposite the insertion opening and the receiving chamber delimited by the perforated wall is spaced from at least one adjacent inner wall of the perfusion channel, wherein the cross section of the perfusion channel in the region of the receiving chamber is not completely occupied by the receiving chamber delimited by the perforated wall, so that the perforated wall is flowed against by a fluid flowing in the longitudinal direction of the perfusion channel from the inlet to the outlet and a partial flow of a fluid flowing through the perfusion channel flows through the receiving chamber and another bypass partial flow flows past the receiving chamber

A sample, such as a cell culture, can thus be introduced through the insertion opening transversely to the flow direction of the perfusion channel into the receiving chamber defined by a perforated wall. It is advantageous to design the insertion opening such that the sample, at least in the initial stage, can adhere to the opening of the insertion opening in the receiving chamber in the form of a droplet-shaped, three-dimensional structure, e.g., through capillary forces. The sample insertion opening can be limited to the opening into the perfusion channel or be designed as a sample introduction channel extending from a sample inlet into the opening to the perfusion channel.

The fluid flowing through the perfusion channel flows onto the perforated wall located in the flow path and, in a bypass partial flow, passes below the receiving chamber, for example, when viewing the perfusion channel with the sample introduction direction vertical and the flow direction horizontal from the introduction opening. The receiving chamber, defined by the perforated wall, is arranged at a distance from the wall area opposite the introduction opening.

A variant is also conceivable in which the perforated wall spans at least one plane transverse to the sample introduction direction of the introduction opening and transverse to the flow direction or extension direction of the perfusion channel, and the bypass is formed above and/or below the at least one horizontal perforated wall section delimiting the receiving chamber when the perfusion channel is viewed with the sample introduction direction and flow direction horizontally aligned. Then, the receiving chamber delimited by the perforated wall, with the wall section of the perforated wall extending from the wall region of the perfusion channel adjacent to the introduction opening, is arranged at a distance from the adjacent, generally parallel, inner wall of the perfusion channel.

In the variant, the receiving chamber can be delimited on the one hand by an upper or lower inner wall of the perfusion channel and on the other hand by a perforated wall spaced apart from it, which in turn is delimited by the other inner wall of the perfusion channel, which is the upper or lower wall delimiting the receiving chamber. inner wall, in order to form the bypass in this intermediate space. However, a variant is also conceivable in which an upper perforated wall and a lower perforated wall are present to delimit the receiving chamber, wherein the upper perforated wall is arranged adjacent to the upper inner wall of the perfusion channel, leaving a bypass space, and the lower perforated wall is arranged adjacent to the lower inner wall of the perfusion channel, leaving a bypass space.

This ensures that the fluid flows through the receiving chamber, while the bypass controls the flow conditions within the receiving chamber. This allows, for example, the flow influences within the receiving chamber to be reduced while simultaneously ensuring sufficient flow when required.

The receiving chamber is therefore not completely in the flow path of the perfusion channel and is therefore exposed to the entire pressure and flow influences of the fluid. On the other hand, it is not simply arranged parallel to the flow path of the perfusion channel and therefore only subjected to flow laterally along the receiving chamber. Rather, the receiving chamber is in the flow path of the perfusion channel and, viewed from the inlet to the outlet in the flow direction or longitudinal direction of the perfusion channel, is subjected to flow and the fluid flows through it. However, only a partial flow of the fluid flowing through the perfusion channel acts on the receiving chamber, while another bypass partial flow can flow past the receiving chamber in order to control the shear forces acting on the sample during flow, for example by reducing them, and to achieve a more even pressure distribution and a reduction and homogenization of the flow velocities in the receiving chamber.

The receiving chamber can, for example, be a cell culture chamber that is designed or used to receive cell tissue as a sample.

The insertion opening can be designed as a capillary channel, which on the one hand opens into the receiving chamber in the perfusion channel and on the other hand opens into a larger filler neck on the outside of the microsystem component in order to accommodate a pipette tip in the filler neck for filling a sample (i.e., an object such as cell tissue). Likewise, the perfusion channel can be designed as a capillary channel and open into and out with larger inlet and outlet necks. Inlet and outlet ports can be configured for connecting tubing lines to connect the microsystem component to a tubing system and at least one pump (e.g., a peristaltic pump) in the tubing system. The ports can be configured as a bore for inserting tubular elements or as a protruding connection port for attaching tubing.

The perforated wall can advantageously be formed by spaced-apart posts in the perfusion channel. This achieves a stable structure. The length of the posts extending between opposing wall sections of the perfusion channel defines a space with a known height, so that the volume and size of the sample can be easily and accurately determined. The space of the receiving chamber between the posts can, if necessary, be examined optically via one of the wall surfaces between which the posts extend. The posts can preferably have a height of 50 to 200 μm. The height can be in the range of 100 μm. Similarly, the perforated wall can also be designed, for example, as a rod-structure wall or as a porous wall made of porous material. Such a wall can be produced additively or subtractively using 3D printing. The rod-structure wall can be formed from interwoven or interlaced, i.e., intersecting rods with spaces between them.

The posts can have a greater length in the longitudinal direction of the perfusion channel than their width transverse to the longitudinal direction of the perfusion channel. This increases the cross-section of the posts compared to cylindrical posts and improves the stability of the perforated wall. This design improves the resistance to forces exerted on the microsystem component when a sample (especially a cell culture) is introduced with a micropipette. Furthermore, the elongated shape of the posts in the flow direction of the perfusion channel, i.e., in the longitudinal direction, is also advantageous with regard to flow influences.

The posts can be circular. However, it is particularly advantageous if the posts have a cross-section that is elliptical, oval, rectangular with rounded corners, or diamond-shaped. Tapering the posts in the direction of flow improves flow behavior. This can reduce turbulence. Furthermore, the connection and load-bearing capacity are improved by the reduced aspect ratio of the posts compared to a circular cylindrical shape, thus improving mechanical stability. The adjacent posts can be offset from each other in the longitudinal direction of the perfusion channel. This ensures the largest possible cross-section of the posts to ensure sufficient stability. The offset simultaneously reduces the effective permeable wall thickness or the length of the interspaces in the direction of flow. The permeability of the perforated wall can thus be improved without compromising stability.

The perforated wall can be curved and define a space that is circular, elliptical, or oval in cross-section. This creates a curved space for receiving the sample that is adapted to the three-dimensional spherical shape, particularly of cell tissue. The introduction opening opens into a receiving chamber that is, in cross-section, quasi-drop-shaped. In this case, the fluid in the perfusion chamber does not flow against a straight perforated wall, but rather impinges on the perforated wall at points offset relative to one another in the direction of flow. This controls the influence of pressure, shear forces, and flow velocity caused by the fluid on the sample contained in the interior of the receiving chamber and can, for example, be further reduced and homogenized by appropriately designing the perforated wall.

Spaced-apart columns can be arranged within the interior of the receiving chamber. This allows a sample to be held at desired positions in the fluid flow even within the receiving chamber.

The columns can be movable. This allows the column structure inside the chamber to adapt to changing environmental conditions, for example, when the sample, such as a cell culture, grows over time and requires more space. The columns can then be partially or completely removed from the chamber.

The spacing between the columns and/or the width and/or height of the columns can be varied by external physical parameters. Such microcolumns can, for example, be made of a shape-memory material that changes its state depending on the influencing factor. Such influencing factors can include temperature, pH value, light, and electrical current or voltage, etc. It is conceivable that electrodes are arranged in the recording chamber for electrically measuring properties of a sample located therein, with the electrodes being connectable or connected to an electronic measuring unit. This allows electrically measurable properties of the sample to be determined while it is in the recording chamber.

It is advantageous if at least one post and/or column is electrically conductive and each forms an electrode. Thus, all or selected posts and/or columns can be made of highly doped silicon or coated with a metal layer, with the electrode being electrically connected to a connecting line or a terminal contact. This allows the electrodes to be connected to an electronic measuring unit.

The microsystem component may have an integrated measuring unit, in particular a measuring unit designed for electrical impedance spectroscopy (EIS), which is connected to the electrodes.

The microsystem component can have multiple receiving chambers in a perfusion channel, each with an insertion opening leading into the receiving chamber. It is also conceivable for the microsystem component to have multiple perfusion channels, each with at least one receiving chamber. The multiple perfusion channels can each have separate inlets and/or outlets or be connected in parallel to a common inlet and/or outlet.

In general, in the context of this application, the words “a/an”, unless expressly defined otherwise, are not to be understood as a number, but as an indefinite article with the literal meaning of “at least one”.

The invention is explained in more detail below using exemplary embodiments with the accompanying drawings. They show:

Fig. 1 - a perspective sketch of a microsystem component with microfluidic

bioreactor;

Fig. 2 - Sketch of the microsystem component in longitudinal section;

Fig. 3 - Sketch of the microsystem component in longitudinal section with exemplary flow velocities in the perfusion channel and the cell culture chamber; Fig. 4 - Sketch of a modified embodiment of the microsystem component with additional columns in the cell culture chamber;

Fig. 5 - Sketch of a modified embodiment of the microsystem component with several cell culture chambers in the perfusion channel;

Fig. 6 - Process flow of a manufacturing method for the production of the microsystem component.

Figure 1 shows a perspective sketch of a microsystem component 1 with a microfluidic bioreactor. The microsystem component 1 has a carrier substrate 2, which can be made, for example, of glass, such as borosilicate glass (e.g., Pyrex®) or siloxanes, such as polydimethylsiloxane PDMS. A cavity body 3 can be applied to the carrier substrate 2. This cavity body can be made, for example, of siloxanes, such as polydimethylsiloxane PDMS, and connected to the top side of the carrier substrate 2. The microsystem component 1 has a perfusion channel 4 with an inlet 5 and an outlet 6. Furthermore, an insertion opening 7 is present, which opens transversely into the perfusion channel 4. In the example, the insertion opening 7 extends channel-like between a sample inlet 8 and the confluence opening leading into the perfusion channel 4. However, it is also conceivable that the confluence opening forms the insertion opening 7, which can be closed, for example, by a cover, after the sample has been introduced.

The perfusion channel 4 and the insertion opening 7, or the inlet channel, can be introduced into the material of the cavity body 3 on the upper side of the carrier substrate 2 in the depth (i.e. in Figure 1 in the Z-direction of the height or thickness, respectively), and/or on the underside of the cavity body 3 in the thickness direction. The inlet 5 and the outlet 6 are introduced into the cavity body 3 at the opposite ends of the perfusion channel 4. The inlet 5 and the outlet 6 can be designed as bores extending approximately perpendicular to the plane of the carrier substrate 2, each forming a connection piece for receiving connecting tubes. It is conceivable that tubular connection pieces protrude from the upper side of the cavity body 3, onto which a connecting tube can be plugged. In the same way, the sample inlet 8 is designed as a bore aligned perpendicular to the plane of the carrier substrate 2. The sample inlet 8 preferably has a diameter to accommodate a micropipette with which a sample, such as in particular a cell culture, can be introduced into the (sample) introduction opening 7. The opening of the insertion opening 7 borders a receiving chamber 9 formed in the perfusion channel 4. The receiving chamber 9 is delimited by a perforated wall 10 in order to make the receiving chamber 9 fluid-permeable in the perfusion channel 4 and thereby largely prevent the sample, such as cell cultures, from being washed out into the perfusion channel 4.

The cross-section of the perfusion channel 4 is determined by its height in the Z direction and its width in the Y direction. To supply the samples (especially cell cultures) introduced into the receiving chamber 9, a supply solution can be introduced into the perfusion channel 4 via the inlet 5 and conveyed in the flow direction F through the perfusion channel 4 and the receiving chamber 9 arranged there to the outlet 6. This can be achieved, for example, with a tubing system and a pump, e.g., a syringe pump, with which continuously or discontinuously controlled amounts of fluid can be introduced into the perfusion channel 4 over time and corresponding amounts can be withdrawn from the outlet 6.

It is also conceivable to introduce active ingredients into the receiving chamber 9 via the perfusion channel 4 in order to examine their effect on the sample (especially a cell culture). For this purpose, an additional inlet can be provided parallel to the inlet 5 in the perfusion channel 4. However, it is simpler to arrange a Y-connector in the tubing system, via which a syringe pump, a drip, or similar device containing the supply solution can be connected on the one hand, and a syringe, tip pump, drip, or similar device containing the drug containing the active ingredient can be connected on the other.

Figure 2 shows a sketch of the microsystem component 2 in longitudinal section. It can be seen that the channel-shaped insertion opening 7 opens transversely into the perfusion channel 4. This opening is surrounded by a perforated wall 10, which extends adjacent to the opening in a partially circular or partially elliptical shape within the perfusion channel 4 and defines a receiving chamber 9. The perforated wall 10 can define a space with a circular, elliptical, or oval cross-section. Such a receiving chamber 9, with wall surfaces curved in the flow direction F, has fluidic advantages.

The perforated wall is formed from posts 11 which are spaced apart from one another in the flow direction F, ie, offset from one another in the X-direction, and which extend in the Z-direction from the floor to the ceiling of the perfusion channel 4. Between the posts 11 there is a space which is large enough to allow sufficient fluid to pass through, and is small enough to prevent parts of the sample, such as cell tissue 12, from flowing through the receiving chamber 9. The distance should be in the range of approximately 10 pm to 70 pm and preferably less than 40 pm.

The aspect ratio of the posts 11 is reduced compared to cylindrical posts 11 to increase mechanical stability. At the same time, the cross-sectional area is increased to increase the bonding area with the surface of the carrier substrate 2. The shape is adapted and aligned to improve mechanical stability in the flow direction F.

The posts 11 can be tapered in the flow direction F. They can be elliptical, as shown. However, other embodiments with oval, rectangular, or diamond-shaped posts 10 are also conceivable. Rectangular posts 11 should have rounded corners to improve flow behavior and thus be approximately elliptical.

The perforated wall 10 does not extend from the opening of the insertion opening 7 to the opposite wall of the perfusion channel 4. Rather, a bypass B is provided between the distal end of the cell culture chamber 9 to the cell culture insertion opening 7 and the adjacent inner wall of the perfusion channel 4. This controls the flow in the receiving chamber 9 and the load on the cell culture 12 through shear forces, pressure, and flow velocity and can, for example, be reduced compared to the embodiment without a bypass or even increased if necessary.

Optionally, posts 11 can be configured as electrodes 13, or additional electrodes 13 can be provided in the receiving chamber 9 independent of the posts 11. The electrodes 13 are connected or connectable to an electronic measuring unit 14 via electrical leads. The measuring unit 14 can be integrated as a semiconductor circuit in the microsystem component 1 or connected to the microsystem component as a separate circuit arrangement via a cable connection and electrical connections. A measuring unit 14 configured for impedance spectroscopy is advantageous.

Electrical impedance spectroscopy (EIS) is a recognized label-free, non-invasive analysis tool for single cells and cell cultures. Using electrodes 13 in the recording chamber 9, EIS functions can be integrated into the microsystem component. 1. Thus, selected posts 11 and/or micropillars 15 can be manufactured from highly doped silicon to simultaneously form electrodes 13. Within the receiving chamber 9, a current density distribution and a field can be adjusted by selecting and arranging the electrodes that are sufficiently homogeneous to detect a 3D cell culture 12 within it using electroimpedance spectroscopy methods.

It has been shown in the structure shown in Figures 1 and 2 that the shear stress in the receiving chamber 9 can be set to a value of less than 0.4 x 10 ^-2 Pa, while the shear stress in bypass B is significantly higher at more than 1.2 x 10 ^-2 Pa.

For example, bypass B for the microflow past the receiving chamber 9 makes it possible to significantly reduce the shear stress in the receiving chamber 9 while still maintaining perfusion through the receiving chamber 9. It can be seen that the highest shear stress is in the perfusion channel 4 next to the receiving chamber 9. The shear stress inside the receiving chamber 9 is significantly lower, which is necessary for perfusion cell culture.

The bypass design solves further problems. For example, it provides more stability to a tumoroid as cellular tissue in the receiving chamber 9, even if there is an unintended pressure change in the perfusion channel 4, thus significantly reducing the effects on the tumoroid.

Bypass B can have a significant impact on pressure distribution. A pressure difference (pO+#p) from the pump can be present on the left side of perfusion channel 4, while the right end can be open to atmospheric pressure (pO). Although a pressure drop occurs along perfusion channel 4, the pressure inside the receiving chamber 9 remains at the average values and completely homogeneous.

The pressure in the receiving chamber 9 and the introduction opening 7 can, for example, be approximately 1.0132501 bar, slightly above the atmospheric pressure pO of approximately 1.0132500 bar present at the right outlet 6, while the inlet 5 has a higher pressure, i.e. an overpressure, of more than 1.0132502 bar.

Through the bypass B, the pressure acting on the sample, e.g. the 3D cell culture 12, is kept constant and homogeneous in the entire recording chamber 9. This Prevents unwanted strong movement of the tubes, syringe pump or microsystem component 1 when the system is removed from an incubator, e.g. for photography, which exerts high pressure on the sample (e.g. cell culture 12) in the recording chamber 9, which can lead to additional stress on the sample or even to rupture of the cell culture 12, e.g. a tumoroid, through the microcapillary. With the

Bypassing the perfusion channel 4 via the bypass B in the perfusion channel 9 solves this problem, as it provides much greater stability to the sample (especially the cell culture 12) inside the receiving chamber. As shown, most of the flow and pressure drop surrounds the receiving chamber 9, while a homogeneous microenvironment is maintained inside the receiving chamber 9. Even in the event of an unintended pressure change in the perfusion channel 4, the impact on the sample (especially the 3D cell culture 12) within the receiving chamber 9 is significantly reduced, so that a tumoroid, in this case, is kept safe and sound inside.

The pressure effect achieved by bypass B can also be used in an implementation of this bypass concept in completely different applications, where it is useful to stabilize the pressure in a specific area of a microchannel while a smaller current flows evenly through it.

At an inlet velocity of the perfusion fluid of, for example, 8.17 x 10 ^-6 m/s, a flow velocity in the interior of the cell culture chamber 9 is established in the construction shown as an example in Figures 1 and 2, which is significantly below

10 x 10 ^-6 m/s and was approximately 5 x 10 ^-6 m/s. The flow velocity in bypass B, however, is significantly higher at more than 20 x 10 ^-6 m/s. Diametrically opposite the inlet opening 7, below the perforated wall 10, flow velocities of approximately 30 x 10' ⁶ m/s are observed.

The flow velocity is much higher near the recording chamber 9 than inside the recording chamber 9, where it is lower than in the central regions, but not zero. The flow velocity within the recording chamber 9 can be reduced by 78% relative to the inlet flow velocity by the bypass B in the illustrated case. Furthermore, the distribution inside the recording chamber 9 is homogeneous. This contributes to providing a stable and homogeneous microenvironment for a cell culture 12 when used as a tumor-on-chip TOC. Mass transport in the recording chamber 9 is greatly reduced, but not eliminated. In the perfusion channel 4, the distribution in the planes near the inlet 5 and the outlet 6 is more homogeneous, and the velocity decreases to zero in the walls. In the yz-planes near the receiving chamber 9, an important difference can be seen between the perfusion channel 4 and the receiving chamber 9 in the design shown as an example in Figures 1 and 2. Although there is still a flow velocity, it is significantly reduced. Furthermore, the distribution in the yz-planes within the receiving chamber 9 is much more homogeneous. This homogeneous distribution of the flow velocity in the receiving chamber 9 can lead to an advantage in 3D cell culture 12, since the mass transport is also much more homogeneous in the z-direction, and all cells are evenly supplied with nutrients and freed from waste products.

Figure 3 shows a sketch of the microsystem component 1 in longitudinal section with exemplary flow velocities in the perfusion channel 4 and the receiving chamber 9.

It is possible to see what is happening with the velocity streamlines in the receiving chamber 9 and bypass B. Most streamlines flow around the receiving chamber 9, but some also pass through the receiving chamber 9. This means that a slow flow is passing through the receiving chamber 9. The dense cluster of streamlines near the receiving chamber 9 creates a high-velocity region. The low density within the receiving chamber 9 ensures uniform flow and mass transport.

Figure 4 shows a sketch of a modified embodiment of the microsystem component 1 with additional columns 15 in the receiving chamber 9.

With such vertical scaffolds within the receiving chamber 9, for example, the cell growth of cell tissue 12 as a sample can be improved by using such microcolumns 15 as a scaffold. If the volume of the receiving chamber 9 is then entirely or partially provided with a scaffold structure, the growth of a 3D cell culture 12 starting from individual cells can be supported. This offers the possibility of starting from a single cell suspension and creating a 3D cell culture structure in situ. The microcolumns 15 can optionally be made of a smart material that allows the width and/or height of the microcolumns 15 to be controlled on-site. The microcolumns 15 can be formed from materials that are altered by external stimuli such as temperature, pH, light, etc. Thus, during an experiment, the width of the microcolumns 15 could be changed, thereby changing the mass transport entering the receiving chamber 9 as well as the shear stress and pressure inside the receiving chamber 9.

Figure 5 shows a sketch of a modified embodiment of the

Microsystem component 1 with several receiving chambers 9 in the perfusion channel 4.

This allows high-throughput screening to be achieved, since a large number of recording chambers 9 can be arranged almost indefinitely along the microfluidic perfusion channel 4, one after the other, and with parallel perfusion channels 4, also next to each other.

The perfusion channel 4 extends from its inlet 5 to the opposite outlet 6. Inlet openings 7 open into the perfusion channel 4 alternately from above and below, or from right and left in the X direction as seen in the flow direction F. Adjacent to each inlet, a receiving chamber 9 is delimited by perforated walls 10 formed from posts 11. In turn, a bypass B leading past a respective receiving chamber 9 is present in the perforation channel 4. The bypasses B are arranged alternately below and above in the flow direction F, or to the right and left of the receiving chamber 9 in the X direction.

Figure 6 shows a process flow of a manufacturing method for producing the microsystem component 1.

For the microfabrication of the microsystem component 1 designed as a microbioreactor, microsystem technology (i.e. technology for the production of microelectromechanical systems) can be used with technologies such as photolithography, deep reactive ion etching, self-assembled monolayer, replica molding and oxygen plasma bonding.

The microfabrication process begins in step A) with a flat substrate, such as a silicon wafer (Si) 16. In step B), a spin coating of titanium primer (Ti) takes place to improve the adhesion of the next layer. In step C), a spin coating of photoresist 18 takes place. In step D), a photolithographic exposure with ultraviolet light UV takes place through a photomask formed from a quartz carrier 19 and a structured chromium coating 20. In step E), a development of the exposed photoresist, i.e. the photoresist 18 after exposure, takes place. In step F), a deep reactive ion etching of the silicon Si 16 is carried out. In the process, depressions 20 are introduced into the silicon wafer 16. In step G), the photoresist, i.e. the exposed photoresist 18 and the Ti primer are removed. What remains is a silicon wafer 16 with depressions 21 in the desired locations.

In step H), a self-assembled monolayer 22 is obtained as an antistiction. In step I), a molding of polydimethylsiloxane PDMS is performed, which is applied to the surface of the silicon wafer 16. In step J), the PDMS stamp 23 is removed. In step K), the polydimethylsiloxane PDMS and glass 24, such as borosilicate glass (e.g., Pyrex®), are exposed to oxygen plasma. In step L), both surfaces, i.e., the carrier substrate 2 made of glass 24 and the cavity body 3 formed from the PDMS stamp 23, are bonded by annealing.

Another manufacturing process for the subtractive or additive construction of the microsystem component 1 is also conceivable. 3D printing, for example, can be used for this purpose. The perforated wall can be formed not only from posts 11. 3D printing, in particular, offers the possibility of forming a porous wall or a rod-structure wall, for example, as a rod structure with intersecting rod structures and intermediate spaces. Such a rod structure includes honeycomb structures and the like. 3D printing improves the connection between the perforated wall and the channel walls, as these are manufactured together from a single material.

The idea of locally stabilizing pressure, shear stress, and flow velocity with a bypass in perfusion channel 4 can essentially be implemented in any channel/tube containing a fluid (air or liquid) where a locally stable region within a fluid flow is required. For example, a probe can be inserted into the stable region to measure the physical or chemical properties of the fluid. It could also be used in chemical reactors with two different chemicals, one in the flow region and the other in the stable region. This allows a very slow reaction to occur at the interface between these two regions.

Another application is in cell culture, such as tumor cells. However, this can also be used for other cell culture types, including healthy cells, to study their response to other fluids, chemicals, drugs, etc.

List of reference symbols

1 microsystem component

2 Carrier substrate

3 cavity bodies

4 Perfusion channel

5 Entrance

6 Outlet

7 Insertion opening

8 Sample inlet

9 Recording chamber

10 perforated wall

11 posts

12 Cell tissue (sample)

13 Electrode

14 measuring unit

15 Column

16 silicon wafers

18 photoresist

19 Quartz

20 chrome

21 recesses

22 self-assembled monolayer

23 PDMS stamps

24 glass

B Bypass

F Flow direction

*****

Claims

Patent claims: 1. Microsystem component (1) with a substrate (2, 3) which has a receiving chamber (9), an insertion opening (7) leading to the receiving chamber (9) and a perfusion channel (4), wherein the perfusion channel (4) is communicatively connected to the receiving chamber (9) and has an inlet (5) and an outlet (6), and wherein the receiving chamber (9) is arranged in the perfusion channel (4) and is delimited by a perforated wall (10), characterized in that the insertion opening (7) opens into the receiving chamber (9) delimited by the perforated wall (10) and the perforated wall (10) surrounds the insertion opening (7), wherein the perforated wall (10) extends from the wall region of the perfusion channel (4) adjacent to the insertion opening (7) into the perfusion channel (4) to the wall region opposite the insertion opening (7), and the perforated wall (10) delimited receiving chamber (9) is spaced from at least one adjacent inner wall of the perfusion channel (4), wherein the cross section of the perfusion channel (4) in the region of the receiving chamber (9) is not completely occupied by the receiving chamber (9) delimited by the perforated wall (10), so that the perforated wall (10) is flowed against by a fluid flowing in the longitudinal direction of the perfusion channel (4) from the inlet (5) to the outlet (6) and a partial flow of a fluid flowing through the perfusion channel (4) through the receiving chamber (9) flows and another bypass partial flow flows past the receiving chamber (9). 2. Microsystem component (1) according to claim 1, characterized in that the perforated wall (10) is formed by spaced-apart posts (11), by a rod-structure wall or by a porous wall in the perfusion channel (4). 3. Microsystem component (1) according to claim 2, characterized in that the Post (11) has a greater length in the longitudinal direction of the Perfusion channel (4) as a width transverse to the longitudinal direction of the perfusion channel (4). 4. Microsystem component (1) according to claim 3, characterized in that the posts (11) are elliptical, oval, rectangular with rounded corners or diamond-shaped in cross section. 5. Microsystem component (1) according to one of claims 2 to 4, characterized in that the respectively adjacent posts (11) are arranged offset from one another in the longitudinal direction of the perfusion channel (4). 6. Microsystem component (1) according to one of the preceding claims, characterized in that the perforated wall (10) is curved and defines a space which is circular, elliptical or oval in section. 7. Microsystem component (1) according to one of the preceding claims, characterized in that columns (15) spaced apart from one another are arranged in the interior of the receiving chamber (9). 8. Microsystem component (1) according to claim 7, characterized in that the columns (15) are movable. 9. Microsystem component (1) according to claim 7 or 8, characterized in that the distance between the columns (15) and/or the width of the columns (15) and/or the height of the columns (15) can be varied by external physical parameters. 10. Microsystem component (1) according to one of the preceding claims, characterized in that electrodes (13) are arranged in the receiving chamber (9) for electrically measuring properties of a sample (12) located in the receiving chamber (9), wherein the electrodes (13) are connectable or connected to an electronic measuring unit (14). 11. Microsystem component (1) according to claim 10 in conjunction with one of claims 2 to 5 or 7 to 9, characterized in that at least one post (11) and/or one column (15) are electrically conductive and each form an electrode (13). 12. Microsystem component (1) according to claim 10 or 11, characterized in that the microsystem component (1) has an integrated measuring unit (14), in particular a measuring unit designed for electrical impedance spectroscopy, which is connected to the electrodes (13). 13. Microsystem component (1) according to one of the preceding claims, characterized in that a plurality of receiving chambers (9) are formed in the perfusion channel (4), each with an insertion opening (7) opening into the receiving chamber (9). 14. Microsystem component (1) according to one of the preceding claims, characterized in that the microsystem component (1) has a plurality of perfusion channels (4), each of which has at least one receiving chamber (9). 15. Microsystem component (1) according to one of the preceding claims, characterized in that the receiving chamber (9) is a cell culture chamber for receiving cell tissue as a sample (12). *****