JP7717364B2 - Organism-on-a-Chip - Google Patents

Description

The present invention relates to a biofunction chip.

In general, new drug development involves conducting cell culture or animal testing before clinical trials to confirm the drug's safety. However, because cultured cells are different from actual human cells, there is a risk that an appropriate assessment of the drug's effects may not be obtained. In addition, animal testing involving the administration of drugs whose safety has not been confirmed has been criticized from the perspective of animal welfare. Therefore, a new experimental platform is needed.

In response to this, Patent Document 1 discloses a microchip-type biofunctional chip that could serve as a novel experimental platform. According to the biofunctional chip in Patent Document 1, alveolar epithelial cells are cultured on the upper side of a central porous membrane, and vascular endothelial cells on the lower side. By driving the walls perpendicular to the membrane from the left and right with a vacuum pump, periodic expansion and contraction is generated, providing the cultured cells with a mechanical stimulus through stretching, thereby recreating the cellular environment of alveoli in vivo.

International Publication No. 2016/010861

The biofunction chip in Patent Document 1 itself is relatively small, but it requires peripheral equipment such as a vacuum pump and syringe pump, as well as piping, and the addition of these devices poses issues such as the unit containing the enlarged biofunction chip not being able to fit into an incubator. For this reason, there is a need for a more compact biofunction chip that includes the pump.

In recent years, research has been progressing on micropumps that use functional fluids. Functional fluids are a general term for fluids that exhibit specific functionality in response to external stimuli. Functional fluids include magnetic fluids, magnetorheological fluids, electrorheological fluids, and electroconjugate fluids, and actuators using these fluids are already being used in industrial products.

Electro-conjugate fluids (ECFs), one type of functional fluid, are functional fluids that generate active flow when a direct current voltage is applied. Pumps using ECFs can generate flow simply by applying voltage to tiny electrodes, without requiring any mechanical configuration, and are therefore expected to serve as a hydraulic pressure source suitable for small fluid distribution systems.

The present invention aims to provide a small biofunction chip with a built-in micropump that uses ECF.

In order to achieve the above object, one representative biofunction chip of the present invention is:
a first elastic membrane having a surface on which cells can be cultured;
a holding plate that holds the first elastic membrane;
a pressure chamber formed in the holding plate;
a drive path connected to the pressure chamber;
a working fluid injected into the pressure chamber and the drive path;
an electrode unit disposed within the drive path;
This is achieved by applying a DC voltage to the electrode unit, causing the working fluid to move within the drive path and changing the pressure in the pressure chamber, thereby applying a tensile stress to the first elastic membrane.

According to the present invention, it is possible to provide a small biofunction chip incorporating a micropump using ECF.
Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments.

FIG. 1 is a perspective view of a biofunction chip according to the first embodiment, and the internal structure is indicated by dotted lines. FIG. 2 is an exploded perspective view of the biofunction chip according to the first embodiment. FIG. 3 is a perspective view of the upper plate with the internal structure visible. FIG. 4 is a diagram schematically illustrating an electrode unit disposed in the first drive path. FIG. 5A is a schematic cross-sectional view showing the operation of the biofunction chip of the first embodiment. FIG. 5B is a perspective view showing the lower plate of the biofunction chip according to the modified example. FIG. 5C is a top view of the lower plate of the modified biofunction chip. FIG. 5D is a schematic cross-sectional view showing the operation of the modified biofunction chip. FIG. 6 is a perspective view of a biofunction chip according to the second embodiment, with the internal structure indicated by dotted lines. FIG. 7 is an exploded perspective view of the biofunction chip according to the second embodiment. FIG. 8 is a perspective view of the upper plate with the internal structure visible. FIG. 9 is a schematic cross-sectional view similar to FIG. 5A, which shows the operation of the biofunction chip of the second embodiment. FIG. 10 is a perspective view of the biofunction chip according to the third embodiment, and the internal structure is indicated by dotted lines. FIG. 11 is an exploded perspective view of the biofunction chip according to the third embodiment. FIG. 12 is a schematic cross-sectional view showing the operation of the biofunction chip of the third embodiment. FIG. 13 is a schematic cross-sectional view showing the operation of the biofunction chip of the third embodiment. FIG. 14 is a perspective view of the biofunction chip according to the fourth embodiment, and the internal structure is indicated by dotted lines. FIG. 15 is an exploded perspective view of the biofunction chip according to the fourth embodiment. FIG. 16 is a schematic cross-sectional view showing the operation of the biofunction chip of the fourth embodiment. FIG. 17 is a perspective view of the biofunction chip according to the fifth embodiment, and the internal structure is indicated by dotted lines. FIG. 18 is an exploded perspective view of the biofunction chip according to the fifth embodiment. FIG. 19 is a schematic cross-sectional view showing the operation of the biofunction chip of the fifth embodiment.

The following describes specific embodiments of the present invention.

(First embodiment)
Fig. 1 is a perspective view of a biofunction chip 10 according to a first embodiment, with the internal structure indicated by dotted lines. Fig. 2 is an exploded perspective view of the biofunction chip 10. Fig. 3 is a perspective view of the upper plate, showing the internal structure. The biofunction chip 10 of the first embodiment is a single-axis tension, double-sided pump-driven type.

The biofunction chip 10 is a thin, roughly rectangular plate with dimensions of, for example, 6 cm long x 4 cm wide, and is composed of an upper plate 11, an elastic membrane (referred to here as the first elastic membrane) 12, a lower plate 13, and a pump substrate 14. The upper plate 11 and lower plate 13 form a holding plate. When the biofunction chip 10 is formed using semiconductor manufacturing processes, it can be mass-produced despite its fine structure. Furthermore, the manufacturing method is not limited to any particular method.

In Figure 2, the upper plate 11 is made of a flexible material such as silicone rubber, and has a first inlet hole 11p, a second inlet hole 11q, a first outlet hole 11s, and a second outlet hole 11t formed near both ends of the longitudinal direction, each penetrating the plate in the vertical direction.

As shown in Figure 3, the lower surface of the upper plate 11 is formed with an upper left groove 11a, an upper middle groove 11b, and an upper right groove 11c, each with a rectangular cross section, extending parallel to one another in the longitudinal direction. A first upper partition wall 11d is formed between the upper left groove 11a and the upper middle groove 11b, and a second upper partition wall 11e is formed between the upper middle groove 11b and the upper right groove 11c.

The upper left groove 11a, the upper middle groove 11b, and the upper right groove 11c extend from near the first inlet hole 11p to near the first outlet hole 11s. The upper middle groove 11b and the first inlet hole 11p are connected via the upper flow path groove 11g, and the upper middle groove 11b and the first outlet hole 11s are connected via the upper flow path groove 11h.

The upper plate 11 is further formed with a first injection hole 11i, a second injection hole 11j, a third injection hole 11k, and a fourth injection hole 11m, each of which penetrates vertically. The first injection hole 11i is connected to one end of the upper left groove 11a via injection groove 11n, and the second injection hole 11j is connected to the other end of the upper left groove 11a via injection groove 11o. The third injection hole 11k is connected to one end of the upper right groove 11c via injection groove 11r, and the fourth injection hole 11m is connected to the other end of the upper right groove 11c via injection groove 11u.

A first rectangular opening 11v and a second rectangular opening 11w are formed in the upper plate 11 on both sides of the upper left groove 11a, upper middle groove 11b, and upper right groove 11c, penetrating the upper plate 11 in the vertical direction. Flexible membrane members 15a and 15b are adhered to the upper surfaces of the first rectangular opening 11v and the second rectangular opening 11w, respectively, closing the upper ends of the first rectangular opening 11v and the second rectangular opening 11w.

A first recess 111 and a second recess 113 are formed on the underside of the upper plate 11, adjacent to the first rectangular opening 11v and the second rectangular opening 11w. The first rectangular opening 11v and the first recess 111 are connected by a communicating groove 11x, and the second rectangular opening 11w and the second recess 113 are connected by a communicating groove 11y.

Next, we will explain the lower plate 13. The lower plate 13 is also made of a flexible material such as silicone rubber. In Figure 2, the upper surface of the lower plate 13, which has the same outer shape as the upper plate 11, has an inlet-side recess 13q formed in correspondence with the second inlet hole 11q of the upper plate 11, and an outlet-side recess 13t formed in correspondence with the second outlet hole 11t.

The upper surface of the lower plate 13 is formed with a lower left groove 13a, a lower middle groove 13b, and a lower right groove 13c, each with a rectangular cross section, corresponding to the upper left groove 11a, the upper middle groove 11b, and the upper right groove 11c, respectively. Furthermore, a first lower partition wall 13d is formed between the lower left groove 13a and the lower middle groove 13b, and a second lower partition wall 13e is formed between the lower middle groove 13b and the lower right groove 13c.

The lower central groove 13b and the inlet recess 13q are connected via the lower flow path groove 13g, and the lower central groove 13b and the outlet recess 13t are connected via the lower flow path groove 13h.

A first hole 131 and a first recess 132, as well as a second hole 133 and a second recess 134, are formed on both sides of the lower left groove 13a, the lower middle groove 13b, and the lower right groove 13c, penetrating vertically. The first recess 132 is connected to the lower left groove 13a via the first groove 135, and the second recess 134 is connected to the lower right groove 13c via the second groove 136.

Next, the elastic membrane 12 will be described. The elastic membrane 12 is sandwiched between the upper plate 11 and the lower plate 13. A through-hole 12q is formed in the elastic membrane 12 corresponding to the second inlet hole 11q of the upper plate 11, and a through-hole 12t is formed in the elastic membrane 12 corresponding to the second outlet hole 11t. Furthermore, a through-hole 121 is formed in the elastic membrane 12 corresponding to the first hole 131 of the lower plate 13, and a through-hole 123 is formed in the elastic membrane 12 corresponding to the second hole 133.

The area sandwiched between the upper and lower grooves 11b and 13b of the elastic membrane 12 forms a porous portion 125 with numerous fine pores. For example, alveolar epithelial cells are cultured on the upper surface of the porous portion 125, and vascular endothelial cells are cultured on the lower surface.

On both sides of the porous portion 125, a first opening 12a corresponding to the upper left groove 11a and the lower left groove 13a, and a second opening 12c corresponding to the upper right groove 11c and the lower right groove 13c, are formed.

In Figure 2, when the elastic membrane 12 is bonded to the underside of the upper plate 11, the open lower end of the upper-middle groove 11b is blocked by the elastic membrane 12. At this time, the first upper partition wall 11d and the second upper partition wall 11e are joined to the elastic membrane 12 so as to sandwich the porous portion 125, thereby sealing the upper-middle groove 11b. In addition, the lower ends of the upper flow channel grooves 11g and 11h are blocked by the elastic membrane 12.

The space enclosed by the upper-middle groove 11b and the elastic membrane 12 is the upper test flow path UP, and the spaces enclosed by the upper flow path grooves 11g and 11h and the elastic membrane 12 are the upper communication paths UP1 and UP2, respectively. Alveolar epithelial cells cultured on the upper surface of the porous portion 125 can come into contact with liquid passing through the upper test flow path UP. Here, the first inlet hole 11p is connected to the upper test flow path UP via the upper communication path UP1, and the first outlet hole 11s is connected to the upper test flow path UP via the upper communication path UP2.

In Figure 2, when the elastic membrane 12 is adhered to the underside of the upper plate 11, the first rectangular opening 11v and the lower end of the communication groove 11x are blocked by the elastic membrane 12. The first rectangular opening 11v with its upper and lower ends blocked constitutes the first reservoir RV1.

Furthermore, when the elastic membrane 12 is adhered to the underside of the upper plate 11, the second rectangular opening 11w and the lower end of the communication groove 11y are blocked by the elastic membrane 12. The second rectangular opening 11w with its upper and lower ends blocked constitutes the second reservoir RV2.

Furthermore, when the elastic membrane 12 is adhered to the lower surface of the upper plate 11, the communication groove 11x with its lower end blocked forms part of the first drive path DP1, which will be described later, and the communication groove 11y with its lower end blocked forms part of the second drive path DP2, which will be described later.

When the elastic membrane 12 is bonded to the underside of the upper plate 11, the open lower ends of the first injection hole 11i and injection groove 11n, and the open lower ends of the second injection hole 11j and injection groove 11o are blocked by the elastic membrane 12, forming injection paths PP1 and PP2 that communicate with the first pressure chamber PC1, which will be described later. The open lower ends of the third injection hole 11k and injection groove 11r, and the open lower ends of the fourth injection hole 11m and injection groove 11u are blocked by the elastic membrane 12, forming injection paths PP3 and PP4 that communicate with the second pressure chamber PC2, which will be described later.

In Figure 2, when an elastic membrane 12 is further bonded to the upper surface of the lower plate 13, the open upper end of the lower center groove 13b is blocked by the elastic membrane 12. At this time, the first lower partition 13d and the second lower partition 13e, which face the first upper partition 11d and the second upper partition 11e, are joined to the elastic membrane 12 so as to sandwich the porous portion 125, thereby sealing the lower center groove 13b. The upper ends of the lower flow channel grooves 13g and 13h are also blocked by the elastic membrane 12.

The space surrounded by the lower-middle groove 13b and the elastic membrane 12 is referred to as the lower test flow path LP, and the spaces surrounded by the lower flow path grooves 13g and 13h and the elastic membrane 12 are referred to as the lower communication paths LP1 and LP2, respectively. Vascular endothelial cells cultured on the lower surface of the porous portion 125 can come into contact with liquid passing through the lower test flow path LP.

Through the first opening 12a in the elastic membrane 12, the upper left groove 11a and the lower left groove 13a communicate with each other, and the upper right groove 11c and the lower right groove 13c communicate with each other. The upper ends of the first groove 135 and the second groove 136 are blocked by the elastic membrane 12. The upper left groove 11a and the lower left groove 13a form a first pressure chamber PC1, and the upper right groove 11c and the lower right groove 13c form a second pressure chamber PC2.

Furthermore, the first groove 135, which is shielded by the elastic membrane 12, connects the first pressure chamber PC1 and the first recess 132, thereby constituting part of the first drive path DP1, and the second groove 136, which is shielded by the elastic membrane 12, connects the second pressure chamber PC2 and the second recess 134, thereby constituting part of the second drive path DP2.

With both sides of the elastic membrane 12 bonded to the upper plate 11 and lower plate 13, the second inlet hole 11q and the inlet-side recess 13q communicate via the through-hole 12q, and the second outlet hole 11t and the outlet-side recess 13t communicate via the through-hole 12t. The second inlet hole 11q communicates with the lower test flow path LP via the lower communication path LP1, and the second outlet hole 11t communicates with the lower test flow path LP via the lower communication path LP2.

Next, the pump substrate 14 will be described. While the pump substrate 14 is shown as an example made up of a combination of a plate with vertically extending grooves or holes and a flat plate, it may also be made from a single plate. This also applies to the embodiments described below.

A first serpentine groove 147 and a second serpentine groove 148 are formed on the top surface of the pump substrate 14. A plurality of electrode units 16 arranged in series and power supply wiring (not shown) are formed in the first serpentine groove 147 and the second serpentine groove 148. By joining the lower plate 13 to the top surface of the pump substrate 14, drive paths DP1 and DP2 are formed, and the electrode units 16 are disposed within the drive paths DP1 and DP2. The drive paths DP1 and DP2 filled with ECF and the electrode units 16 form a micropump.

A recess 141 is formed at one end of the first serpentine groove 147 and a recess 142 is formed at the other end, and a recess 143 is formed at one end of the second serpentine groove 148 and a recess 144 is formed at the other end.

When the pump substrate 14 is bonded to the lower plate 13, the recess 141 communicates with the first recess 111 via the first hole 131 in the lower plate 13 and the through-hole 121 in the elastic membrane 12, so one end of the first drive path DP1 is connected to the first reservoir RV1. Furthermore, the recess 142 communicates with the first recess 132, so the other end of the first drive path DP1 is connected to the first pressure chamber PC1.

Furthermore, when the pump substrate 14 is joined to the lower plate 13, the recess 143 communicates with the second recess 113 via the second hole 133 in the lower plate 13 and the through-hole 123 in the elastic membrane 12, so one end of the second drive path DP2 is connected to the second reservoir RV2. Furthermore, the recess 144 communicates with the second recess 134, so the other end of the second drive path DP2 is connected to the second pressure chamber PC2.

Figure 4 is a schematic diagram showing the electrode units 16 arranged in the first drive path DP1 and the second drive path DP2. The electrode unit 16 has a slit electrode (also called a positive electrode) 16a and a triangular prism electrode (also called a negative electrode) 16b. The other electrode units 16 have a similar configuration. The pump substrate 14 and lower plate 13 (not shown in Figure 4), which form the inner wall of the first drive path DP1, are each made of an insulator.

The slit electrodes 16a are arranged on both sides of the axis of the drive path DP1 (or DP2), with a gap between them. On the other hand, the triangular prism electrode 16b has its pointed tip facing the gap between the slit electrodes 16a.

A high DC voltage of several tens of volts to several tens of kV can be applied from a DC power supply to the slit electrode 16a and the triangular prism electrode 16b. The slit electrode 16a is connected to the positive electrode, and the triangular prism electrode 16b is connected to the negative electrode.

In Figure 2, the biofunction chip 10 is formed by stacking and bonding the pump substrate 14, lower plate 13, elastic membrane 12, and upper plate 11. First, before bonding the membrane members 15a and 15b, ECF is injected into the pressure chambers PC1 and PC2 as follows.

Referring to FIG. 1, when ECF is injected through injection hole 11i, the injected ECF fills the first pressure chamber PC1 via injection path PP1 and then reaches the first reservoir RV1 via the first drive path DP1. Excess ECF passes from the first pressure chamber PC1 through injection path PP2 and overflows to the outside through injection hole 11j. After the injection is complete, injection holes 11i and 11j are closed using a clamp or the like, and the top of the first reservoir RV1 is sealed with membrane member 15a. However, the method of closing the injection port is not limited to the above.

Similarly, when ECF is injected through injection hole 11k, the injected ECF fills the second pressure chamber PC2 via injection path PP3 and then reaches the second reservoir RV2 via the second drive path DP2. Excess ECF passes from the second pressure chamber PC2 through injection path PP4 and overflows to the outside through injection hole 11m. After the injection is complete, injection holes 11k and 11m are closed using a clamp or the like, and the top of the second reservoir RV2 is sealed with membrane member 15b. However, the method of closing the injection port is not limited to the above. For example, a fluid described in U.S. Patent No. 6,495,071 can be used as ECF, but this is not limiting.

(Operation of the biofunction chip)
5A is a schematic cross-sectional view showing the operation of the biofunctional chip 10 of the first embodiment. While a single electrode unit 16 is shown on each of the drive paths DP1 and DP2 in FIG. 5A, in reality, multiple electrode units 16 are arranged in series. Note that the triangular prism electrode 16b of the electrode unit 16 on the first drive path DP1 is arranged on the first pressure chamber PC1 side, and the triangular prism electrode 16b of the electrode unit 16 on the second drive path DP2 is arranged on the second pressure chamber PC2 side. Each electrode unit 16 is connected to a direct current power source DC, and the power supply is controlled in an integrated manner by a control device (not shown).

Alveolar epithelial cells are cultured in advance on the upper surface of the porous portion 125, with the first upper partition wall 11d and second upper partition wall 11e, which form part of the inner wall of the first pressure chamber PC1, tightly adhering to their side surfaces. Vascular endothelial cells are cultured on the lower surface of the porous portion 125, with the first lower partition wall 13d and second lower partition wall 13e, which form part of the inner wall of the second pressure chamber PC2, tightly adhering to their side surfaces.

Furthermore, air is injected through the first inlet hole 11p. The injected air passes through the upper connecting passage UP1, enters the upper test flow path UP, and comes into contact with the alveolar epithelial cells. Excess air passes through the upper connecting passage UP2 downstream from the upper test flow path UP and is discharged through the first outlet hole 11s. Note that a liquid may be injected instead of air.

Meanwhile, blood is injected through the second inlet hole 11q. The injected blood passes through the lower connecting passage LP1, enters the lower test flow path LP, and comes into contact with vascular endothelial cells. Excess blood passes through the lower connecting passage LP2 downstream from the lower test flow path LP, and is discharged from the second outlet hole 11t. The gas or liquid injected into the upper connecting passage UP1 and the lower connecting passage LP1 can be selected appropriately depending on the cells being cultured.

When a signal from the control device does not apply a DC voltage to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the drive paths DP1 and DP2, the internal pressure of pressure chambers PC1 and PC2 is equivalent to atmospheric pressure. Therefore, as shown in Figure 5A (a), the first upper partition wall 11d and the second upper partition wall 11e, and the first lower partition wall 13d and the second lower partition wall 13e are maintained in their pre-deformation states.

In response to this, when a DC voltage is applied to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the drive paths DP1 and DP2 in response to a signal from the control device, the ECF in the drive paths DP1 and DP2 flows from the pressure chambers PC1 and PC2 toward the reservoirs RV1 and RV2, as shown in Figure 5A (b). The elastic deformation of the membrane members 15a and 15b allows the reservoirs RV1 and RV2 to increase their capacity for storing the flowing ECF.

The flow of ECF reduces the internal pressure of pressure chambers PC1 and PC2, which forces the first upper partition 11d and the second upper partition 11e apart, pulling both sides of the alveolar epithelial cells left and right as shown in Figure 5A(b). The first lower partition 13d and the second lower partition 13e are also forced apart, pulling both sides of the vascular endothelial cells left and right as shown in Figure 5A(b). This provides a stretching stimulus to the alveolar epithelial cells and vascular endothelial cells, making it possible to recreate the alveolar environment in vivo.

When power supply to the electrode unit 16 is stopped, the membrane members 15a and 15b return from elastic deformation, allowing ECF to return from reservoirs RV1 and RV2 to pressure chambers PC1 and PC2, restoring their internal pressures. This causes the first upper partition wall 11d and the second upper partition wall 11e, and the first lower partition wall 13d and the second lower partition wall 13e, to return to their original positions shown in Figure 5A(a), causing the alveolar epithelial cells and vascular endothelial cells to return to their original states. Furthermore, the elastic force of the porous portion 125 membrane itself causes the upper partition walls 11d and 11e, and the lower partition walls 13d and 13e, to return to their original positions.

In this way, by repeatedly supplying power to the electrode unit 16 and cutting it off, the alveolar epithelial cells and vascular endothelial cells repeatedly expand and contract, allowing gas exchange between oxygen in the alveoli and carbon dioxide in the blood to be achieved through the porous portion 125, just like in the lungs of a human body. The biofunctional chip 10 of this embodiment can accurately evaluate, for example, changes in blood caused by a viral infection (airborne infection) due to breathing, or how the efficiency of gas exchange changes when a drug solution is injected into the blood, without the need for animal testing.

(Modification)
In particular, in a living body, blood flow becomes uneven near where blood vessels branch, and the mechanical stimulation due to shear force acting on vascular endothelial cells also becomes uneven. A biofunction chip 10' according to a modified example including such a structure is shown below.

Figure 5B is a perspective view showing the lower plate 13' of the biofunction chip 10', and Figure 5C is a top view of the lower plate 13'. The configuration of the biofunction chip 10' other than the lower plate 13' is the same as in the first embodiment, so repeated explanations will be omitted.

The lower plate 13' differs from the lower plate 13 of the first embodiment in the shape of the lower center groove 13b'. Other configurations are the same as the lower plate 13 of the first embodiment, so the same reference numerals are used for common configurations and their description will be omitted.

In Figure 5C, a central lower partition 13x extending parallel to the lower partitions 13d and 13e is formed in the center of the lower-middle groove 13' sandwiched between the lower partitions 13d and 13e. A third lower partition 13y is formed between the first lower partition 13d and the central lower partition 13x, and a fourth lower partition 13z is formed between the central lower partition 13x and the second lower partition 13e. The third lower partition 13y and the fourth lower partition 13z are equal in length. The central lower partition 13x is formed long so as to protrude from both ends of the third lower partition 13y and the fourth lower partition 13z, but is shorter than the overall length of the lower-middle groove 13'.

The lower middle groove 13b' is divided into, from the upstream side, a first portion BV1 in which only the lower partitions 13d and 13e are arranged; a second portion BV2 in which only the central lower partition 13x is arranged between the lower partitions 13d and 13e; a third portion BV3 in which the third lower partition 13y, the central lower partition 13x, and the fourth lower partition 13z are arranged between the lower partitions 13d and 13e; a fourth portion BV4 in which only the central lower partition 13x is arranged between the lower partitions 13d and 13e; and a fifth portion BV5 in which only the lower partitions 13d and 13e are arranged.

The cross-sections of each flow path between the partitions become smaller from the first portion BV1 to the third portion BV3, and become larger from the third portion BV3 to the fifth portion BV5. Therefore, the first portion BV1 corresponds to a small artery in the human body, which has a relatively large cross-section, the second portion BV2 corresponds to an arteriole, which has a smaller cross-section than an arteriole, the third portion BV3 corresponds to a capillary, which has the smallest cross-section, and the fourth portion BV4 corresponds to a venule, which in turn corresponds to a small vein. This makes it possible to reproduce, for example, the branching structure of capillaries in the alveoli.

5D is a schematic cross-sectional view of the third portion BV3, illustrating the operation of the biofunctional chip 10'. As shown in FIG. 5D, the upper ends of the central lower partition 13x, the third lower partition 13y, and the fourth lower partition 13z are abutted against and bonded to the lower surface of the porous portion 125. Therefore, facing the upper test flow path UP, a minute cross-sectional passage (first capillary passage) is formed between the first lower partition 13d and the third lower partition 13y, a minute cross-sectional passage (second capillary passage) is formed between the third lower partition 13y and the central lower partition 13x, a minute cross-sectional passage (third capillary passage) is formed between the central lower partition 13x and the fourth lower partition 13z, and a minute cross-sectional passage (fourth capillary passage) is formed between the fourth lower partition 13z and the second lower partition 13e.

The operation of the biofunction chip 10' is basically the same as in the first embodiment. When a signal from the control device does not apply a DC voltage to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the drive paths DP1 and DP2, the internal pressure of the pressure chambers PC1 and PC2 is equivalent to atmospheric pressure. Therefore, as shown in Figure 5D(a), the first upper partition 11d, the second upper partition 11e, the third lower partition 13y, the central lower partition 13x, the fourth lower partition 13z, and the first lower partition 13d and the second lower partition 13e are maintained in their pre-deformation states.

In response to this, when a DC voltage is applied to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the drive paths DP1 and DP2 in response to a signal from the control device, the ECF in the drive paths DP1 and DP2 flows from the pressure chambers PC1 and PC2 toward the reservoirs RV1 and RV2, as shown in Figure 5D (b). The elastic deformation of the membrane members 15a and 15b in the reservoirs RV1 and RV2 increases the volume for storing the flowing ECF.

The flow of ECF reduces the internal pressure of pressure chambers PC1 and PC2, forcing the first upper partition wall 11d and the second upper partition wall 11e apart, pulling both sides of the alveolar epithelial cells left and right as shown in FIG. 5D(b). The first lower partition wall 13d and the second lower partition wall 13e are also forced apart, and as the porous portion 125 stretches, the third lower partition wall 13y and the fourth lower partition wall 13z also deform, pulling both sides of the vascular endothelial cells left and right as shown in FIG. 5D(b). This provides a stretching stimulus to the alveolar epithelial cells and vascular endothelial cells, recreating the in vivo alveolar environment. Structures that mimic the branching of capillaries, such as this modified example, can be similarly incorporated into other embodiments described below.

Second Embodiment
Fig. 6 is a perspective view of a biofunction chip 10' according to the second embodiment, with the internal structure indicated by dotted lines. Fig. 7 is an exploded perspective view of the biofunction chip 10'. Fig. 8 is a perspective view of the upper plate, showing the internal structure. Figs. 6 to 8 show the biofunction chip 10' in a state where the longitudinal axis is rotated 180 degrees relative to Figs. 1 to 3.

The biofunction chip 10' in this embodiment is a single-axis tension, one-sided pump drive type. Components that are common to the first embodiment are designated by the same reference numerals, and duplicate explanations will be omitted.

The biofunction chip 10' is formed from an upper plate 11', an elastic membrane 12', a lower plate 13', and a pump substrate 14', which do not have the structures related to the second drive path DP2 and second reservoir RV2 of the first embodiment.

Instead, in the biofunction chip 10', the drive path DP1 is connected to both the first pressure chamber PC1 and the second pressure chamber PC2. Specifically, in the pump substrate 14', the serpentine path 147 branches into branch paths 147a and 147b. Furthermore, the recess 142a formed at the end of the branch path 147a is connected to the first recess 132 of the lower plate 13'. Furthermore, the recess 142b formed at the end of the branch path 147a is connected to the second recess 134 of the lower plate 13'. As a result, the ends of the drive path DP1 are connected to the first pressure chamber PC1 and the second pressure chamber PC2.

(Operation of the biofunction chip)
9 is a schematic cross-sectional view similar to FIG. 5A, showing the operation of the biofunctional chip 10' of the second embodiment. As in the first embodiment, alveolar epithelial cells are cultured on the upper surface of the porous portion 125, and vascular endothelial cells are cultured on the lower surface thereof.

When a signal from the control device does not apply a DC voltage to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the drive path DP1, the internal pressure of pressure chambers PC1 and PC2 is equivalent to atmospheric pressure. Therefore, as shown in Figure 9(a), the first upper partition wall 11d and the second upper partition wall 11e, and the first lower partition wall 13d and the second lower partition wall 13e are maintained in their pre-deformation states.

In response to this, when a DC voltage is applied to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the drive path DP1 in response to a signal from the control device, the ECF in the drive path DP1 flows from the pressure chambers PC1 and PC2 toward the reservoir RV1, as shown in Figure 9(b). The elastic deformation of the membrane member 15a in the reservoir RV1 increases the volume for storing the flowing ECF.

As the ECF flows, the internal pressure of pressure chambers PC1 and PC2 decreases via branch paths 147a and 147b, forcing the first upper partition 11d and the second upper partition 11e apart, pulling both sides of the alveolar epithelial cells left and right as shown in Figure 9(b), and also forcing the first lower partition 13d and the second lower partition 13e apart, pulling both sides of the vascular endothelial cells left and right as shown in Figure 5A.

When power supply to the electrode unit 16 is stopped, the membrane members 15a and 15b return from elastic deformation, allowing ECF to return from reservoirs RV1 and RV2 to pressure chambers PC1 and PC2, restoring their internal pressures. This causes the first upper partition wall 11d and the second upper partition wall 11e, and the first lower partition wall 13d and the second lower partition wall 13e, to return to their original positions shown in Figure 9(a), causing the alveolar epithelial cells and vascular endothelial cells to return to their original states. Furthermore, the elastic force of the porous portion 125 membrane itself causes the upper partition walls 11d and 11e, and the lower partition walls 13d and 13e, to return to their original positions.

According to the second embodiment, the configuration of the biofunction chip 10' can be further simplified.

(Third embodiment)
Fig. 10 is a perspective view of the biofunction chip 20 according to the third embodiment, with the internal structure indicated by dotted lines. Fig. 11 is an exploded perspective view of the biofunction chip 20. The biofunction chip 20 of the third embodiment is a diaphragm-driven type.

The biofunction chip 20 is composed of an upper plate 21, a first elastic membrane 22, an intermediate plate 23, a second elastic membrane 24, a lower plate 25, and a pump substrate 26. The upper plate 21, intermediate plate 23, and lower plate 25 form a holding plate.

The rectangular upper plate 21 has a circular central opening 21a formed on one side in the short direction, and an inlet hole 21b and an outlet hole 21c, each with a smaller diameter than the central opening 21a, are formed on either side of the central opening 21a.

The first elastic membrane 22, which has the same outer shape as the upper plate 21, has a porous portion 22a with many fine holes corresponding to the central opening 21a, and intermediate holes 22b and 22c corresponding to the inlet hole 21b and outlet hole 21c.

A long hole opening 23f is formed in the intermediate plate 23, which has the same outer shape as the first elastic membrane 22. The long hole opening 23f has a long hole center portion 23a corresponding to the central opening 21a, and long hole end portions 23b, 23c corresponding to the inlet hole 21b and outlet hole 21c. Furthermore, the long hole center portion 23a and the long hole end portions 23b, 23c are connected by flow paths 23d and 23e, respectively.

The second elastic membrane 24 has a rectangular shape with a larger area than the intermediate plate 23.

The lower plate 25, which has the same outer shape as the second elastic membrane 24, has a lower opening 25a formed corresponding to the central portion 23a of the elongated hole, and drive holes 25b and 25c formed corresponding to the end portions 23b and 23c of the elongated hole.

Furthermore, a central rectangular opening 25g is formed in the lower plate 25 at a location that protrudes from the intermediate plate 23, and end rectangular openings 25h and 25i are formed on either side of the central rectangular opening 25g.

A central serpentine groove 261 is formed on the upper surface of the pump base plate 26, which has the same outer shape as the lower plate 25. A first serpentine groove 262 and a second serpentine groove 263 are formed on either side of the central serpentine groove 261. One end of the central serpentine groove 261 is a circular recess 26a located at a position corresponding to the lower opening 25a, and the other end is a rectangular recess 26g located at a position corresponding to the central rectangular opening 25g.

Furthermore, one end of the first serpentine groove 262 is a circular recess 26b located at a position corresponding to the drive hole 25b, and the other end is a rectangular recess 26h located at a position corresponding to the end rectangular opening 25h.

Furthermore, one end of the second serpentine groove 263 is a circular recess 26c located at a position corresponding to the drive hole 25c, and the other end is a rectangular recess 26i located at a position corresponding to the end rectangular opening 25i.

The central serpentine groove 261, the first serpentine groove 262, and the second serpentine groove 263 are provided with multiple electrode units 16 arranged in series and power supply wiring (not shown). The electrode units 16 are similar to those shown in Figure 5A.

The biofunction chip 20 is formed by stacking and bonding the upper plate 21, first elastic membrane 22, middle plate 23, second elastic membrane 24, lower plate 25, and pump substrate 26.

When the upper plate 21, first elastic membrane 22, and intermediate plate 23 are joined together, the upper surface of the porous portion 22a is disposed within the central opening 21a, and its lower surface faces the elongated hole central portion 23a. Furthermore, the inlet hole 21b communicates with the elongated hole end portion 23b via the intermediate hole 22b, and the outlet hole 21c communicates with the elongated hole end portion 23c via the intermediate hole 22c.

Here, the inlet port IP is formed by the inlet hole 21b and the intermediate hole 22b, and the outlet port OP is formed by the outlet hole 21c and the intermediate hole 22c.

Furthermore, when the lower plate 25, with the second elastic membrane 24 adhered to its upper surface, is joined to the intermediate plate 23, the open lower ends of the flow paths 23d and 23e are blocked by the second elastic membrane 24, forming an internal passage IT whose ends are connected to the inlet port IP and outlet port OP. Within the internal passage IT, the elongated hole end 23b forms the first valve chamber VC1 connected to the inlet port IP, and the elongated hole end 23c forms the second valve chamber VC2 connected to the outlet port OP.

The upper end of the lower opening 25a, the upper ends of the drive holes 25b and 25c, the upper end of the central rectangular opening 25g, and the upper ends of the end rectangular openings 25h and 25i are also blocked by the second elastic membrane 24. Here, the interior of the lower opening 25a blocked by the second elastic membrane 24 constitutes the central pressure chamber PCC, the interior of the drive hole 25b blocked by the second elastic membrane 24 constitutes the first pressure chamber PC1, and the interior of the drive hole 25c blocked by the second elastic membrane 24 constitutes the second pressure chamber PC2. Furthermore, the interior of the central rectangular opening 25g blocked by the second elastic membrane 24 constitutes the central reservoir RVC, the interior of the end rectangular opening 25h blocked by the second elastic membrane 24 constitutes the first reservoir RV1, and the interior of the end rectangular opening 25i blocked by the second elastic membrane 24 constitutes the second reservoir RV2.

Furthermore, by joining the pump substrate 26 to the lower plate 25, the open upper end of the central serpentine groove 261 is closed to form the central drive path DPC, and the open upper ends of the first serpentine groove 262 and the second serpentine groove 263 are closed to form the drive paths DP1 and DP2. The electrode unit 16 is disposed within the central drive path DPC and the drive paths DP1 and DP2. The second elastic membrane 24, the drive paths DP1 and DP2 containing the working fluid, and the pump substrate 26 constitute a valve mechanism.

(Operation of the biofunction chip)
12 and 13 are schematic cross-sectional views showing the operation of the biofunction chip 20 of the third embodiment, with FIG. 12 showing the AA cross section of FIG. 10 and FIG. 13 showing the BB cross section of FIG.

In Figures 12 and 13, a single electrode unit 16 is shown on the central drive path DPC and the drive paths DP1 and DP2, but in reality, multiple electrode units 16 are arranged in series. The triangular prism electrode 16b of the electrode unit 16 on the central drive path DPC is located on the central pressure chamber PCC side, the triangular prism electrode 16b of the electrode unit 16 on the first drive path DP1 is located on the first reservoir RV1 side, and the triangular prism electrode 16b of the electrode unit 16 on the second drive path DP2 is located on the second reservoir RV2 side. Each electrode unit 16 is connected to a direct current power source DC, and the power supply is controlled collectively by a control device (not shown).

Here, alveolar epithelial cells are cultured on the upper surface of the porous portion 22a, and vascular endothelial cells are cultured on the lower surface. The alveolar epithelial cells are in contact with air through the central opening 21a of the upper plate 21.

Furthermore, blood is injected through the inlet port IP, and the injected blood passes through the internal passage IT and is discharged from the outlet port OP.

The valve operation of the biofunction chip 20 will now be explained. When a signal from the control device does not apply a DC voltage to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the drive paths DP1 and DP2, the internal pressure of the first pressure chamber PC1 and the second pressure chamber PC2 is equivalent to atmospheric pressure. Therefore, as shown in Figure 12(a), the second elastic membrane 24 facing the first pressure chamber PC1 and the second pressure chamber PC2 and the first valve chamber VC1 and the second valve chamber VC2 is maintained in its pre-deformation state.

In response to this, when a DC voltage is applied to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the drive path DP1 in response to a signal from the control device, the ECF in the drive path DP1 flows from the first reservoir RV1 toward the first pressure chamber PC1, as shown in Figure 12(b). This causes the second elastic membrane 24 facing the first reservoir RV1 to elastically deform, allowing the movement of ECF from the first reservoir RV1.

As the ECF flows, the internal pressure of the first pressure chamber PC1 increases, causing the facing second elastic membrane 24 to deform toward the first valve chamber VC1 and close the inlet port IP. This blocks the inflow of blood through the inlet port IP.

Furthermore, when a DC voltage is applied to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the drive path DP2 in response to a signal from the control device, the ECF in the drive path DP2 flows from the second reservoir RV2 toward the second pressure chamber PC2, as shown in Figure 12(b). This causes the second elastic membrane 24 facing the second reservoir RV2 to elastically deform, allowing the movement of ECF from the first reservoir RV1.

As the ECF flows, the internal pressure of the second pressure chamber PC2 increases, causing the facing second elastic membrane 24 to deform toward the second valve chamber VC2 and close the outlet port OP. This blocks the outflow of blood through the outlet port OP.

When the power supply to the electrode units 16 of the drive paths DP1 and DP2 is stopped, the internal pressure of the pressure chambers PC1 and PC2 decreases. This causes the second elastic membrane 24 facing the valve chambers VC1 and VC2 to return to its original elastic deformation, opening the inlet port IP and outlet port OP. The inlet port IP and outlet port OP can be closed and opened independently.

Next, the expansion and contraction operation of the biofunction chip 20 will be explained. When a signal from the control device does not apply a DC voltage to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the central drive path DPC, the internal pressure of the central pressure chamber PCC is equivalent to atmospheric pressure. Therefore, as shown in Figure 13(a), the second elastic membrane 24 facing the central pressure chamber PCC is maintained in its pre-deformation state.

In response to this, when a DC voltage is applied to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the central drive circuit DPC in response to a signal from the control device, the ECF in the central drive circuit DPC flows from the central pressure chamber PCC toward the central reservoir RVC, as shown in Figure 13(b). The second elastic membrane 24 facing the central reservoir RVC elastically deforms, thereby storing the ECF that has flowed into the central reservoir RVC, thereby increasing its volume.

At this time, if the electrode units of the drive paths DP1 and DP2 are driven to close the inlet port IP and outlet port OP as shown in Figure 12(b), blood does not flow in or out of the internal passage IT, so the volume remains constant. At this time, the flow of ECF within the central drive path DPC causes the internal pressure of the central pressure chamber PCC to decrease, elastically deforming the second elastic membrane 24 facing it downward. As shown in Figure 13(b), the porous portion 22a, which is part of the first elastic membrane 22, also elastically deforms downward, causing tensile stress to act on the porous portion 22a. In response, the alveolar epithelial cells on the upper surface of the porous portion 22a bend and stretch, and the vascular endothelial cells on the lower surface of the porous portion 22a also bend and stretch.

When the power supply to the electrode unit 16 of the central drive path DPC is stopped, the internal pressure of the central pressure chamber PCC returns to its original state. As a result, the second elastic membrane 24 and porous portion 22a return to their original positions shown in Figure 13(a) due to the elastic force acting on the membranes themselves, and the alveolar epithelial cells and vascular endothelial cells also return to their original states.

According to the third embodiment, despite its compact configuration, the timing of supplying liquid (or gas) to cells can be freely changed by applying a DC voltage, causing the cells to expand and contract.

(Fourth embodiment)
Fig. 14 is a perspective view of the biofunction chip 30 according to the fourth embodiment, with the internal structure indicated by dotted lines. Fig. 15 is an exploded perspective view of the biofunction chip 30. The biofunction chip 30 of the fourth embodiment is a recessed, double-sided drive type.

The biofunction chip 30 is composed of a third membrane member 31, an upper plate 32, a first elastic membrane 33, an intermediate plate 34, a second elastic membrane 35, a lower plate 36, and a pump substrate 37. The upper plate 32 and lower plate 36 together form a holding plate.

The rectangular third membrane member 31 is made from a flexible material and has a first inlet hole 31e, a first outlet hole 31f, a second inlet hole 31g, a second outlet hole 31h, a third inlet hole 31a, a third outlet hole 31b, a fourth inlet hole 31c, and a fourth outlet hole 31d.

The upper plate 32, which has the same external shape as the third membrane member 31, has an intermediate hole 32a formed corresponding to the third inlet hole 31a, an intermediate hole 32b formed corresponding to the third outlet hole 31b, an intermediate hole 32c formed corresponding to the fourth inlet hole 31c, and an intermediate hole 32d formed corresponding to the fourth outlet hole 31d.

Furthermore, the upper plate 32 has U-shaped cutout grooves 32j and 32k arranged symmetrically on both sides of the central partition wall (second partition wall) 32i. Cutout grooves 32j and 32k each have straight portions 32m and 32n adjacent to partition wall 32i.

One end of the cut groove 32j is a circular end 32e corresponding to the first inlet hole 31e, and the other end of the cut groove 32j is a circular end 32f corresponding to the first outlet hole 31f. Furthermore, one end of the cut groove 32k is a circular end 32g corresponding to the second inlet hole 31g, and the other end of the cut groove 32k is a circular end 32h corresponding to the second outlet hole 31h.

The first elastic membrane 33, which has the same outer shape as the upper plate 32, has a membrane hole 33a formed corresponding to the intermediate hole 32a, a membrane hole 33b formed corresponding to the intermediate hole 32b, a membrane hole 33c formed corresponding to the intermediate hole 32c, and a membrane hole 33d formed corresponding to the intermediate hole 32d.

Furthermore, porous portions 33m and 33n are formed in the first elastic membrane 33, corresponding to the straight portions 32m and 32n of the cut grooves 32j and 32k.

The intermediate plate 34 has the same outer shape as the first elastic membrane 33, and cutout grooves 34j and 34k are arranged symmetrically on both sides of the partition (first partition) 34i corresponding to partition 32i. Cutout grooves 34j and 34k have straight portions 34m and 34n corresponding to straight portions 32m and 32n, but their overall shape is different from that of cutout grooves 32j and 32k.

One end of the cut groove 34j is a circular end 34a corresponding to the membrane hole 33a, and the other end of the cut groove 34j is a circular end 34b corresponding to the membrane hole 33b. Furthermore, one end of the cut groove 34k is a circular end 34c corresponding to the membrane hole 33c, and the other end of the cut groove 34k is a circular end 34d corresponding to the membrane hole 33d.

The second elastic membrane 35 has a rectangular shape with a larger area than the intermediate plate 34.

The lower plate 36, which has the same outer shape as the second elastic membrane 35, has a first rectangular opening 36s formed in correspondence with the straight portions 34m and 34n, and a second rectangular opening 36t formed in a position extending beyond the intermediate plate 34.

A serpentine groove 37u is formed on the upper surface of the pump base plate 37, which has the same outer shape as the lower plate 36. One end of the serpentine groove 37u is a rectangular recess 37s located at a position corresponding to the first rectangular opening 36s, and the other end is a rectangular recess 37t located at a position corresponding to the second rectangular opening 36t.

The serpentine groove 37u is formed with multiple electrode units 16 arranged in series and power supply wiring (not shown). The electrode units 16 are similar to those shown in Figure 5A.

The biofunction chip 30 is formed by stacking and bonding the third membrane member 31, upper plate 32, first elastic membrane 33, middle plate 34, second elastic membrane 35, lower plate 36, and pump substrate 37.

When the third membrane member 31, upper plate 32, first elastic membrane 33, and intermediate plate 34 are joined together, the first inlet hole 31e is connected to the circular end 32e, the first outlet hole 31f is connected to the circular end 32f, the upper and lower ends of the cut groove 32j are blocked, and a first test flow path UP11 is formed with the first inlet hole 31e and first outlet hole 31f as its ends.

Furthermore, the second inlet hole 31g is connected to the circular end 32g, the second outlet hole 31h is connected to the circular end 32h, and the upper and lower ends of the cut groove 32k are blocked, forming a second test flow path UP12 with the second inlet hole 31g and the second outlet hole 31h as its ends. At this time, the straight section 32m is located above the porous section 33m, and the straight section 32n is located above the porous section 33n.

Furthermore, the third inlet hole 31a is connected to the circular end 34a via the intermediate hole 32a and the membrane hole 33a, and the third outlet hole 31b is connected to the circular end 34b via the intermediate hole 32b and the membrane hole 33b. The upper and lower ends of the cut groove 34j are blocked, forming a third test flow path UP21 whose ends are the third inlet hole 31a and the third outlet hole 31b.

Furthermore, the fourth inlet hole 31c is connected to the circular end 34c via the intermediate hole 32c and the membrane hole 33c, and the fourth outlet hole 31d is connected to the circular end 34d via the intermediate hole 32d and the membrane hole 33d. The upper and lower ends of the cut groove 34k are sealed, forming a fourth test flow path UP22 with the fourth inlet hole 31c and the fourth outlet hole 31d as its ends. At this time, the straight section 34m is located directly below the porous section 33m, and the straight section 34n is located directly below the porous section 33n. Because the lower end of the partition wall 32i and the upper end of the partition wall 34i are joined to the first elastic membrane 33 in opposing positions, the test flow paths UP11-UP22 are sealed without any fluid leakage.

Furthermore, when the lower plate 36, with the second elastic membrane 35 adhered to its upper surface, is joined to the intermediate plate 34, the open upper end of the first rectangular opening 36s and the second rectangular opening 36t are blocked by the second elastic membrane 35.

Furthermore, when the pump substrate 37 is joined to the lower plate 36, the first rectangular opening 36s communicates with the rectangular recess 37s, and the second rectangular opening 36t communicates with the rectangular recess 37t. Here, the inside of the first rectangular opening 36s, which is shielded by the second elastic membrane 35, constitutes the pressure chamber PC, and the inside of the second rectangular opening 36t, which is shielded by the second elastic membrane 35, constitutes the reservoir RV.

Furthermore, by joining the pump substrate 37 to the lower plate 36, the open upper end of the serpentine groove 37u is closed, forming the drive path DP. The electrode unit 16 is disposed within the drive path DP.

(Operation of the biofunction chip)
FIG. 16 is a schematic cross-sectional view showing the operation of the biological function chip 30 of the fourth embodiment.

In Figure 16, a single electrode unit 16 is shown on the drive path DP, but in reality, multiple electrode units 16 are arranged in series. Note that the triangular prism electrode 16b of the electrode unit 16 on the drive path DP is arranged on the pressure chamber PC side. Each electrode unit 16 is connected to a direct current power source DC, and the power supply is controlled in an integrated manner by a control device (not shown).

Here, different alveolar epithelial cells are cultured on the upper surfaces of the porous portions 33m and 33n, and different vascular endothelial cells are cultured on the lower surfaces.

Furthermore, air is injected through the first inlet hole 31e and the second inlet hole 31g. The injected air enters the first test flow path UP11 and the second test flow path UP12, respectively, and comes into contact with the alveolar epithelial cells. Excess air passes through the first test flow path UP11 and the second test flow path UP12 and is discharged through the first outlet hole 31f and the second outlet hole 31h.

Meanwhile, blood is injected through the third inlet hole 31a and the fourth inlet hole 31c. The injected blood enters the third test flow path UP21 and the fourth test flow path UP22, respectively, and comes into contact with vascular endothelial cells. Excess blood passes through the third test flow path UP21 and the fourth test flow path UP22 and is discharged through the third outlet hole 31b and the fourth outlet hole 31d.

Next, the expansion and contraction operation of the biofunction chip 30 will be described. When a signal from the control device does not apply a DC voltage to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the drive path DP, the internal pressure of the pressure chamber PC is equivalent to atmospheric pressure. Therefore, as shown in Figure 16(a), the first elastic membrane 33 and the second elastic membrane 35 are maintained in their pre-deformation states.

In response to this, when a DC voltage is applied to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the drive path DP in response to a signal from the control device, the ECF in the drive path DP flows from the pressure chamber PC toward the reservoir RV, as shown in Figure 16(b). The second elastic membrane 35 facing the reservoir RV elastically deforms, storing the ECF that has flowed into the reservoir RV and increasing its volume.

As the ECF flows, the internal pressure of the pressure chamber PC decreases, causing the second elastic membrane 35 facing it to deform downward. This causes the partitions 34i and 32i to shift downward, causing the first elastic membrane 33 and third membrane member 31 to deform and collapse. This also causes the porous portions 33m and 33n, which are part of the first elastic membrane 33, to elastically deform downward, causing tensile stress to act on the porous portions 33m and 33n. In response, the alveolar epithelial cells on the upper surfaces of the porous portions 33m and 33n are pulled left and right and stretched, and the vascular endothelial cells on the lower surfaces of the porous portions 33m and 33n are also pulled left and right and stretched.

When the power supply to the electrode unit 16 of the central drive path DPC is stopped, the internal pressure of the pressure chamber PC decreases. As a result, the second elastic membrane 35 and porous portions 33m, 33n return to their original positions shown in Figure 16(a) due to the elastic force acting on the membranes themselves, and the alveolar epithelial cells and vascular endothelial cells also return to their original states.

In the fourth embodiment, the test flow paths UP11 to UP22 are provided independently, allowing, for example, two types of alveolar epithelial cells and vascular endothelial cells to be evaluated simultaneously under the same conditions, thereby improving the efficiency of preclinical trials, for example.

Fifth Embodiment
Fig. 17 is a perspective view of a biofunction chip 30' according to the fifth embodiment, with the internal structure indicated by dotted lines. Fig. 18 is an exploded perspective view of the biofunction chip 30'. The biofunction chip 30' of the fifth embodiment is a recessed, one-sided pump-driven type, and components common to the fourth embodiment are designated by the same reference numerals, and redundant explanations will be omitted.

The biofunction chip 30' is formed from a third membrane member 31', an upper plate 32', a first elastic membrane 33', an intermediate plate 34', a second elastic membrane 35, a lower plate 36, and a pump substrate 37, which do not have structures related to the second test flow path UP12 and the fourth test flow path UP22 of the first embodiment.

Specifically, the third membrane member 31', upper plate 32', first elastic membrane 33', and intermediate plate 34' have a configuration in which they are cut at the midpoint in the short direction compared to the first embodiment. The second elastic membrane 35, lower plate 36, and pump substrate 37 have the same configuration as the first embodiment.

(Operation of the biofunction chip)
FIG. 19 is a schematic cross-sectional view showing the operation of the biofunction chip 30' of the fifth embodiment.

Here, alveolar epithelial cells are cultured on the upper surface of the porous portion 33m, and vascular endothelial cells are cultured on the lower surface.

Furthermore, air is injected through the first inlet hole 31e, and the injected air enters the first test flow path UP11 and comes into contact with the alveolar epithelial cells. Excess air passes through the first test flow path UP11 and is discharged through the first outlet hole 31f.

Meanwhile, blood is injected through the third inlet hole 31a, and the injected blood enters the third test flow path UP21 and comes into contact with the vascular endothelial cells. Excess blood passes through the third test flow path UP21 and is discharged through the third outlet hole 31b.

Next, the expansion and contraction operation of the biofunction chip 30' will be explained. When a signal from the control device does not apply a DC voltage to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the drive path DP, the internal pressure of the pressure chamber PC is equivalent to atmospheric pressure, as shown in Figure 19(a). Therefore, the first elastic membrane 33' and the second elastic membrane 35 are maintained in their pre-deformation states.

In response to this, when a DC voltage is applied to the slit electrode 16a and triangular prism electrode 16b of the electrode unit 16 in the drive path DP in response to a signal from the control device, the ECF in the drive path DP2 flows from the pressure chamber PC toward the reservoir RV, as shown in Figure 19(b). The second elastic membrane 35 facing the reservoir RV elastically deforms, storing the ECF that has flowed into the reservoir RV and increasing its volume.

As the ECF flows, the internal pressure of the pressure chamber PC decreases, causing the second elastic membrane 35 facing it to deform downward. This causes the partitions 34i and 32i to shift downward, causing the first elastic membrane 33' and third membrane member 31 to deform and collapse. This also causes the porous portion 33m, which is part of the first elastic membrane 33', to elastically deform downward, and tensile stress acts on the porous portion 33m. In response, the alveolar epithelial cells on the upper surface of the porous portion 33m are pulled left and right and stretch, and the vascular endothelial cells on the lower surface of the porous portion 33m are also pulled left and right and stretch.

When the power supply to the electrode unit 16 of the central drive path DPC is stopped, the internal pressure of the pressure chamber PC decreases. As a result, the second elastic membrane 35 and porous portion 33m return to their original positions shown in Figure 19(a) due to the elastic force acting on the membranes themselves, and the alveolar epithelial cells and vascular endothelial cells also return to their original states.

According to the fifth embodiment, the configuration of the biofunction chip 30' can be further simplified.

10, 10', 20, 30, 30' Biofunction chip 11, 11' Upper plate 12, 12' Elastic membrane 13, 13' Lower plate 14, 14' Pump substrate 16 Electrode unit 21 Upper plate 22 First elastic membrane 23 Middle plate 24 Second elastic membrane 25 Lower plate 25
26 Pump base plate 31, 31' Third membrane member 32, 32' Upper plate 33, 33' First elastic membrane 34, 34' Intermediate plate 35 Second elastic membrane 36 Lower plate 37 Pump base plate

Claims (14)

a first elastic membrane having a surface on which cells can be cultured;
a holding plate that holds the first elastic membrane;
a pressure chamber formed in the holding plate;
a drive path connected to the pressure chamber;
a working fluid injected into the pressure chamber and the drive path;
an electrode unit disposed within the drive path;
When a DC voltage is applied to the electrode unit, a working fluid moves within the drive path, causing a change in pressure in the pressure chamber, thereby applying a tensile stress to the first elastic film.
A biological function chip characterized by: the pressure chamber faces the cells cultured on the first elastic membrane across a partition wall joined to the first elastic membrane;
2. The biological function chip according to claim 1. the holding plate is formed to contain the cells cultured on the first elastic membrane and has a flow path through which a fluid can pass;
3. The biological function chip according to claim 1 or 2. Cells can be cultured on both sides of the first elastic membrane, and the flow channels are arranged in pairs so as to contain each cell.
4. The biological function chip according to claim 3. the pressure chambers are arranged on both sides of the first elastic membrane with the cells cultured therein between, and a pair of the drive paths are connected to the pressure chambers, respectively;
5. The biological function chip according to claim 1, wherein the biological function chip is a microorganism. the pressure chambers are arranged on both sides of the first elastic membrane with the cells cultured therebetween, and the single drive path is connected to the pair of pressure chambers;
5. The biological function chip according to claim 1, wherein the biological function chip is a microorganism. Further comprising a second elastic membrane parallel to and spaced from the cell cultivable surface of the first elastic membrane,
The pressure chamber is disposed on the opposite side of the second elastic membrane from the first elastic membrane.
2. The biological function chip according to claim 1. A flow path through which a fluid can pass is disposed between the first elastic film and the second elastic film.
8. The biological function chip according to claim 7. The device further includes a valve mechanism that blocks the inflow of fluid into the flow channel and the outflow of fluid from the flow channel,
The valve mechanism includes a working fluid injected into a valve drive passage and an electrode unit disposed in the valve drive passage.
The biological function chip according to claim 8 . The cell culture device further includes a second elastic membrane and a third elastic membrane spaced apart from each other on both sides of the cell culture surface of the first elastic membrane,
The pressure chamber is disposed on the opposite side of the second elastic membrane from the first elastic membrane.
2. The biological function chip according to claim 1. a flow path through which a fluid can pass is disposed between the first elastic membrane and the second elastic membrane and between the first elastic membrane and the third elastic membrane;
The biological function chip according to claim 10. a first partition wall connecting the first elastic membrane and the second elastic membrane and a second partition wall connecting the first elastic membrane and the third elastic membrane are disposed at positions facing each other;
12. The biological function chip according to claim 10 or 11. a pair of flow paths through which a fluid can pass are disposed between the first elastic membrane and the second elastic membrane, with the first partition wall sandwiched therebetween; and a pair of flow paths through which a fluid can pass are disposed between the first elastic membrane and the third elastic membrane, with the second partition wall sandwiched therebetween.
The biological function chip according to claim 12 . a single flow path through which a fluid can pass is disposed, the single flow path being surrounded by the first elastic membrane, the second elastic membrane, and the first partition wall; and a single flow path through which a fluid can pass is disposed, the single flow path being surrounded by the first elastic membrane, the third elastic membrane, and the second partition wall.
The biological function chip according to claim 12 .