WO2002031107A2

WO2002031107A2 - Support structure for a bioreactor and bioreactor

Info

Publication number: WO2002031107A2
Application number: PCT/CH2001/000609
Authority: WO
Inventors: Rainer Fuchs; Erdal Karamuk; Jörg Mayer
Original assignee: Sefar Ag
Priority date: 2000-10-09
Filing date: 2001-10-09
Publication date: 2002-04-18
Also published as: CH694165A5; AU2001291590A1; WO2002031107A3

Abstract

A support structure for a bioreactor has a porous membrane (2) and a first textile structure (4) which is located in the direct proximity of said membrane. A second fabric (3) is located directly on the membrane (2), lying therefore between the membrane (2) and said first textile structure (4). This second fabric (3) has a considerably finer structure than the first textile structure (4). The provision of the additional fabric (3) detaches the accumulation of cells (6) from the membrane (2) and as a result, there is no diffusion resistance for these cells (6) on the textile surface. This improves the supply of nutrients locally, the adherence of the cells (6) in the respective wide-meshed intermediate area (5) being optimised.

Description

Support structure for a bioreactor and bioreactor

The invention relates to a support structure for a bioreactor with a porous membrane and a textile structure arranged in the immediate vicinity and a bioreactor constructed from this support structure.

Such a support structure is from the magazine "Tissue Engineering for Therapeutic Use 3" from the "Proceedings of the Third International Symposium of Tissue Engineering for Therapeutic Use, Tokyo, 4-5 September 1998" from the article "Scaffold structure for a bioartificial liver support system "by J. Mayer, E. Kara uk, K. Interevic, T. Akaike and E. Wintermantel on pages 87 to 97. There, in particular, FIG. 1B explains a structure that is used for the common cultivation of hepatocytes and non-parenchymal cells The approach lies in the necessity of arranging the hepatocytes as closely as possible to the non-parenchymal cells via a porous polymer membrane, which is partially biodegradable, so that the individual cells come into close contact There are cavities between the woven polymer fabric, which are used to hold the hepatocytes, and the fabric is made up of monofilaments t.

Two porous polymer membranes or two textile materials are arranged opposite each other in order to obtain spaces for the plasma / medium flow. The support structure • has a flat, film-like side in the membrane and a structured fabric side with pores between 800 and 50 μ corresponding to the fabrics proposed there. The film of the membrane is mechanically attached to and between the fibers.

An intensive exchange of substances is necessary for the intended use of such support structures in metabolically active cells. This can consist in the delivery and absorption of substances, e.g. the metabolism of toxins in the liver, insulin metabolism in the pancreas or urea metabolism in the kidney. The prior art uses the membrane both as a material barrier with a diffusion resistance and as the surface on which the cells are attached. In particular, when using at least partially biodegradable membranes, efforts are made to ensure the closest possible spatial contact between cells lying on opposite sides of the membrane.

The precautionary and cell growth values that can be achieved with this support structure form a first step towards an artificial organ system, for example a liver support system. But they are not enough.

From GB 2 297 980 a plate-shaped bioreactor is known, which is essentially flat. The surface is supplied with plasma and oxygen in two directions perpendicular to each other and with nutrients in a transverse direction. Hollow fibers in particular are used for the supply. The disadvantage of this construction is the limited thickness, since all supply paths are constructed in the longitudinal direction and do not allow any variation of the support structures in the vertical direction.

On the basis of this prior art, the object of the invention is to provide a support structure for a bioreactor and a bioreactor which has more favorable conditions for dif differentiation and metabolic performance as well as better transport properties.

This object is achieved according to the invention for a support structure for a bioreactor with the features of the preamble of claim 1 in that a further tissue is arranged directly on the membrane, which lies between the membrane and said first tissue. This has a considerably finer structure.

By providing this additional tissue, the attachment of cells is detached from the membrane and therefore there is no diffusion resistance on the textile surface for these cells. This enables an improved nutrient supply locally, whereby the adhesion of the cells in the respective, coarse-meshed interspace is optimized.

In one exemplary embodiment of the invention, a further fine tissue structure which is substantially identical to the second tissue is applied on the opposite side of the first tissue, so that a cell growth cavity is formed between the coarse meshes of the first tissue. A second large-mesh fabric is applied to this third fabric, which has, for example, half a mesh size and forms a flow channel for the blood supply.

This makes it possible to produce a bioreactor that can reach any thickness and thus stands out from the disadvantageous elongated tubular reactors.

Further advantageous exemplary embodiments are characterized in the subclaims. The invention will now be described by way of example using exemplary embodiments in the drawings. 1 shows a support structure for a bioreactor according to a first embodiment, FIG. 2 shows a support structure for a bioreactor according to a second embodiment, FIG. 3 shows an illustration of a bioreactor according to the invention, and FIG. 4 shows an enlarged detail illustration for the distribution of 3 in a bioreactor.

1 shows a first exemplary embodiment of a support structure 1 for a bioreactor according to the invention. Another term for element 1 is also cell carrier. The schematic representation is based on a porous membrane, in particular a polymer membrane, which prevents the escape of cells, but allows the passage of nutrients and gases through diffusion. Such a polymer membrane 2 can e.g. made of expanded Teflon, PEEK or other polymer materials. On this membrane 2, which is clamped in a bioreactor, for example, a close-meshed sieve 3 is placed and on this a wide-mesh fabric 4. These are flat structures with defined porosity, which have a periodic structure. It can also be extruded fabric made of polymer material. Metal nets, e.g. made of titanium. All of these embodiments are summarized under the term “textile structure”, which is used synonymously with “fabric” or “textile fabric”.

The term close-mesh sieve 3 is to be understood as a fine structure acting as a diaphragm with pore sizes between 3 and 50 μm, whereas a wide-mesh network 4 has pore sizes between 50 and 800 μm. These textile structures can consist of monofilaments that have a size between 10 and 100 microns.

In the area 5 between two meshes of the wide-mesh network 4, cells 6 in particular are deposited, of which the outline and the cell nucleus are shown schematically. With the aid of such a support structure, a cavity is created, through which a nutrient fluid is passed in the direction of the arrow 7, which fluid is aligned with the cells 6 by means to be described in connection with FIG. 4 (arrow 8) and penetrates them.

Fig. 2 shows a second embodiment of the invention, which has the same basic structure, i.e. the support structure 11 has a membrane 2, a fine-mesh network 3 and a coarse-mesh network 4. However, the support structure 11 is then covered on the side of the coarse structure 4 opposite the fine structure 3 with a further fine-mesh network 13, which to the Cavitation 15 between the two networks 13 and 3 leads. Furthermore, a second coarse-mesh network is placed on the second fine-mesh network 13, which in the exemplary embodiment shown has half the mesh size. The half mesh width allows a greater swirling of fluids flowing in the direction of arrow 17 in the direction of the second fine-meshed network 13. The reference numeral 16 denotes parenchymaic cells which are deposited on the second fine-meshed tissue 13. This enables direct contact between the cells 15 and the further cells 16 via the pores of the second fine-mesh fabric 13.

FIG. 3 shows a bioreactor with a support structure according to FIGS. 1 and 2. In all drawings, the same reference symbols are used for the same features. The excerpt from the bioreak Tor shows several, here 4, stacked support structures 11, which are each arranged upside down. Between two membranes there is a cavity 25, for example of the size of 30 micrometers, so that appropriate nutrient liquids or oxygen can be passed through. Only a second coarse-mesh network 14 is arranged between the two fine-mesh networks 13, so that a cavity 35 is formed here, through which a fluid flow 17 is passed. Alternatively, this cavity could also be created by using tubular structures (eg so-called “micro tubes”).

In FIG. 4 it can be seen here that the symmetrically arranged monofilaments of the second coarse-mesh fabric 14 cause a swirling of the nutrient flow 17 according to the arrows 27, so that the liquid passes through the second fabric layer 13 to the cells, which the the substances contained in the liquid can metabolize.

The first fine fabric layer 3 can be placed, welded or glued to the membrane 2, for example. The individual filaments of the coarse-mesh fabrics 4 and 14 can be designed to be hollow in order to allow liquid to be removed. They can be configured individually, at periodic intervals or as a network as sensor fibers, for example to measure the oxygen partial pressure or to carry out pH measurements, and to be able to regulate these parameters by external control options in the periphery. Furthermore, they can serve as actuator elements, for example for introducing heat, for catalysis by electrochemistry or for sound introduction as a dispersing medium of cells 5 in the cavities 15 and 25. The fibers forming the coarse-meshed networks 4 and 14 or the small diameter filaments of the small-mesh networks 3 and 13 can also be used as optical fibers for corresponding be known applications designed.

It is also possible to design the fine-mesh fabric 3 and the coarse-mesh fabric 4 or the fine-mesh fabric 13 and the coarse-mesh fabric 14 as a double-layer or generally multi-layer fabric in order to produce a greater distance between individual structures without using thicker filaments.

Surface-treated "textile fabrics" or support structures that have been treated using plasma technology, chemical and / or physical processes, for example, can control and / or influence cell growth, cell orientation and cell positioning.

It is also possible to fold or roll the support structures shown in the drawings as just to achieve an increase in surface area, which can lead to improved nutrient absorption in the central areas.

What is essential is the possibility of maintaining an intensive nutrient exchange over short distances, since the volume obtained in conventional tubular reactors or plate reactors is designed here in terms of thickness. In this way, the inadequate supply gradients in tubular or long plate reactors can be avoided, or specific gradients can be designed.

It is also possible to first enrich a structure according to FIG. 1 with first cells 6 and to separately cultivate a structure corresponding to the upper part of FIG. 2 (second fine-mesh structure 13 and second coarse-mesh structure 14) for the enrichment of blood cells, and only then then together conclude. Thus, by decoupling the two growth processes, they can be individually optimized before assembling in the bioreactor. In this way, highly complex artificial organ systems can be successfully set up.

Claims

claims

1. Support structure for a bioreactor with a porous membrane (2) and a first textile structure (4) arranged in the immediate vicinity, characterized in that a second fabric (3) is arranged directly on the membrane (2), which between the membrane (2) and said first textile structure (4), and that the second fabric (3) has a structure which is considerably finer than that of the first textile structure (4).

2. Support structure according to claim 1, characterized in that a third fabric (13) is arranged on the first textile structure (4), which has a fine mesh corresponding to the size of the second fabric (3).

3. Support structure according to claim 2, characterized in that a fourth fabric (14) is arranged on the third fabric (13), which has a fine mesh approximately corresponding to the size of the first fabric (4).

4. Support structure according to claim 2, characterized in that the fourth fabric (14) compared to the first fabric (4) has half the mesh size.

5. Support structure according to one of claims 1 to 4, characterized in that the second and / or third fabrics compared to the first and / or fourth fabrics have a smaller mesh size by a factor of 3 to 10.

6. Bioreactor with a support structure according to one of claims 1 to 5, characterized in that two identical support structures with the membranes (2) opposite one another in an were arranged, which is of the order of magnitude of the thickness of the second fabric (3).

7. Bioreactor according to claim 6, characterized in that it consists in the thickness of a sequence of repeating support structures consisting of a sequence of membrane (2), second fabric (3), first textile structure (4), third fabric (13 ), fourth fabric (14), third fabric (13), first textile structure (4), second fabric (3) and membrane (2).

8. Bioreactor according to one of the preceding claims 6 or 7, characterized in that a control device is provided, by means of which a flow generating device, a temperature setting unit, a gassing unit, a degassing unit and / or further supply units can be controlled and / or regulated.

9. Bioreactor according to one of the preceding claims 6 to 8, characterized in that the bioreactor is tubular and that the substantially flat support structure is arranged in a rolled shape in the tubular bioreactor.

10. Bioreactor according to one of the preceding claims 6 to 8, characterized in that one or more of the fabrics (3, 4, 13, 14) are surface-treated and that in each case a biocompatible surface is formed for the adhesion of the organic material.