WO2022180187A1

WO2022180187A1 - Biocompatible apparatus and system for creating in vitro cell cultures

Info

Publication number: WO2022180187A1
Application number: PCT/EP2022/054715
Authority: WO
Inventors: Paolo MASSOBRIO; Marietta PISANO; Francesca CALLEGARI; Martina BROFIGA
Original assignee: Universita' Degli Studi Di Genova
Priority date: 2021-02-24
Filing date: 2022-02-24
Publication date: 2022-09-01
Also published as: IT202100004313A1

Abstract

A Biocompatible apparatus for creating in vitro cell cultures comprises a support structure defining a culture chamber and provided with a dividing device being positioned to define at least two different culture regions in the culture chamber and so configured to avoid any fluid passage between the at least two culture regions, the dividing device being provided with a holding device for holding a separating membrane so that the separating membrane is interposed between the at least two different culture regions, and at least one separating membrane coupled to the holding device made of a biocompatible material and being provided with pores so dimensioned to allow the passage of fluids and/or of cellular connections therethrough and to avoid the passage of cellular bodies through the separating membrane and between the at least two culture regions. A biocompatible system for creating in vitro cell cultures is also provided.

Description

Biocompatible apparatus and system for creating in vitro cell cultures

The invention relates to a biocompatible apparatus and a system for creating in vitro interconnected 3D cell cultures.

The invention aimed at a biocompatible apparatus and a system for creating in vitro 3D cell cultures, in particular cultures of cells of human brain.

Cell cultures have been widely used for many years to investigate the behaviour and the response of groups of cells to a particular electrical stimulus or drug, or in general to a perturbation modifying the condition of the groups of cells. The first models were 2D cell cultures, in which cells were grown on a rigid support, usually a Petri dish. It is important that in vitro systems resemble as much as possible the response of the real in vivo system to the perturbation. In many cases, the 2D cell cultures are unable to provide a response which is close to the response of the real biological systems.

The limitations of the 2D cell cultures are even more evident when complexes cell systems or organs should be studied. The organs are structured collections of different types of cells, where each type of cell has a specific function, and the different types of cells communicate with others in the same organ to perform the right behaviour of the organ. Therefore, different types of cells are involved in the response of an organ to an external stimulus.

The known 2D cell cultures are unable to provide reliable in vitro systems. For overcoming some of above indicated limitations of the 2D cell cultures and for achieving a more reliable response from the in vitro systems, in vitro 3D models have been proposed to mimic in more reliable manner the response of the cell systems to an external perturbation.

Nevertheless, as indicated before, in a complex cell structure, like for example an organ, or a cell structure involving different type of cells, many different types of cells are included. For this reason, realistic in vitro cell culture models should take into account the heterogeneity of the cells and the different behaviour of the different cells in the response to a perturbation.

Additionally, the different cells in real cell systems are spatially connected following well- defined topological principles: in other words, they are not all arranged on the same plane, and this spatial distribution strongly affects the behaviour of the different cells and their response to an external perturbation. The in vitro cell model should be mimic as much as possible the complex 3D structure of the in vivo systems. To mimic in vitro the 3D structures of cell systems, some solutions have been proposed, using for example glass beads, or others biocompatible 3D scaffolds, which promotes higher levels of cell differentiation and tissue organization in relation to the 2D cell-culture systems.

A 3D cell culture allows a more natural shape of the cells to be obtained.

Nevertheless, the known 3D cell culture models fail to mimic many aspects of the cellular properties of an organ including, for example, tissue-to-tissue interfaces (e.g., epithelium and vascular endothelium), spatiotemporal gradients of chemicals, and the mechanically active microenvironments (e.g., arteries’ vasoconstriction and vasodilator responses to temperature differentials). Traditional 3D cell culture models have all the above indicated drawbacks.

Moreover, the type of cells and interactions between the different cells change from organ to organ. Therefore, the so called “organ-on-a-chip” (OOC) systems have been developed. The OOC is a fit for purpose fabricated microfluidic-based device, containing living engineered organ substructures in a controlled micro- or nano-environment. The OOC is suitable for simulating one or more aspects of the dynamics, functionality and (patho)physiological response of an organ in vivo, like for example the activities, mechanics and physiological response of an organ and organ systems. The OOCs are organ specific, and the structure of the support and the device should be adapted to the different organs.

For example, in 2012 Kanagasabapathi and co-workers, presented a dual compartment system coupled to Micro Electrode Arrays (MEAs) for co-culturing neuronal heterogeneous sub-populations, composed of cortical and thalamic neurons, and recording their spontaneous activity. The system is composed of two interconnected Polydimethylsiloxane (PDMS) chambers that allow both compartmentalization and control over the fluidic microenvironment. A drawback connected with the dual-compartment device (Kanagasabapathi) is that it is unable to create tridimensional structures and do not allow the spatial communication in 3D between the different modules, like for example the cortical module and the thalamic module.

Moreover, the OOCs are very highly specific, and the models must be fitted to the specific organ to be investigated.

Therefore, the need remains for a reliable in vitro model allowing cell cultures to be prepared, which more reliably mimics the real cell systems and thus allows for a better understanding of the basic physiology of the cell systems.

Additionally, the need remains for a cell culture system which is suitable for reproducing simultaneously many characteristics of real cell systems.

In particular, a reliable in vitro model to better understand the physiology of the neuronal system is needed.

It is an object of the invention to provide an apparatus for in vitro models that reliably mimic the behaviour of a cell system like, for example neuronal cell assemblies.

Another object of the invention is to provide an apparatus for in vitro models that reliably mimic the behaviour of a complex cell system, as for example the neuronal one. Another object of the invention is to provide an apparatus for in vitro model that reproduces the physical and functional connections between the different types of cells in a cell system.

An object of the invention is to provide an apparatus for in vitro models that reproduces the physical and functional connection between the different type of cells, preferably the physical and functional connection between the different type of cells in the brain system, or neuronal system.

The scope of the invention is to provide a cell culture apparatus that is suitable for obtaining a cell culture, which mimics the behaviour of a complex cell system like neuronal assemblies and of the brain system taking into account the complexity of the cell system.

A further scope of the invention is to provide a cell culture system that is suitable for obtaining a cell culture that is suitable for mimicking the behaviour of a complex cell system like neuronal assemblies and of the brain system taking into account the complexity of the cell system. According to an aspect of the invention, it is provided a biocompatible apparatus for creating in vitro cell cultures.

The apparatus preferably comprises a support structure defining a culture chamber. Preferably, the support structure is provided with at least one dividing device for dividing the culture chamber in at least two different culture regions in the culture chamber. Preferably, the at least one dividing device is so configured to seal the at least two culture regions to avoid any passage therebetween.

Preferably, the at least one dividing device is provided with a holding device for holding a separating membrane.

Preferably, the holding device is so configured that the separating membrane is interposed between the at least two different culture regions. Preferably, the apparatus comprises at least one separating membrane coupled to the holding device and arranged to separate the at least two different culture regions. Preferably, the separating membrane is made of a biocompatible material.

Preferably, the separating membrane has pores whose dimensions allow the passage of fluids and/or of cellular connections through the separating membrane and avoid the passage of cellular bodies through the separating membrane and between the at least two culture regions.

The separating membrane puts the two different culture regions in fluid connection allowing the passage of material therebetween. At the same time, the separating membrane impedes the passage of material having certain dimensions between the at least two culture regions. In other words the cells bodies do not migrate between the different culture regions but remain in the culture region in which they have been positioned, however at the same time the cells of the different culture regions may establish functional mutual interconnections one with another. Therefore cells of different the could be plated in the different culture regions without causing the mix of the cells of different type.

The separating membrane allows a selective passage of material between the at least two culture regions.

Owing to this aspect of the invention, it is obtained an apparatus, which is suitable for obtaining in vitro 3D cell cultures with different type of cells in which the different cells are mutually interconnected.

Owing to this aspect of the invention it is obtained an apparatus that is suitable for obtaining heterogeneous cell cultures.

Owing to this aspect of the invention it is obtained an apparatus that is suitable for obtaining modular cell cultures. Owing to this aspect of the invention it is obtained an apparatus that is suitable for obtaining cell cultures interconnected at different levels along the z-axis.

Owing to this aspect of the invention it is obtained an apparatus suitable for obtaining cell cultures belonging to the same organ or cell system which are mutually interconnected. The apparatus of the invention is further suitable for mimicking the reaction of a cell culture to an external stimulus, or perturbation

The apparatus of the invention is suitable for mimicking the natural physiology of a cell culture, either formed by homogeneous and heterogeneous cells.

The cell culture obtained with the apparatus of the invention allows mimicking the modularity, the 3D structure of the cell subsystem, the 3D morphology of the connections between the different cells types of a system.

The apparatus of the invention is suitable for mimicking the modularity, the 3D structure of the cell subsystem, the 3D morphology of the connections between cells of the same type in a homogeneous cell culture. Thus, it is possible to mimic the behaviour of a complex cell system, like for example an organ. As an example, the behaviour of the brain or neuronal system may be reliably created with the apparatus of the invention.

In particular, it is possible to grow different type of cells in the different culture regions of the apparatus. The apparatus of the invention allows building 3D modular interacting subpopulations of heterogenous cells, like for example neurons, and also promotes their connection in the three-dimensions, XYZ.

Owing to the apparatus of the invention, it is possible to obtain models for testing the response of a cell culture, like neuronal assemblies, to different external perturbations like, for example, electrical stimulations, acoustic manipulations, drugs, etc. Owing to the apparatus of the invention, it is possible to reduce the number of in vivo experiments since very reliable results are obtained through the in vitro experiments conducted with the apparatus of the invention.

This greatly reduces the costs involved with pharmaceutical research. This also greatly reduces the ethical problems connected with pharmaceutical research.

Moreover, the apparatus of the invention may be successfully used to investigate some diseases affecting large-scale interconnected cell populations. For example, the apparatus of the invention may be successfully used for investigating neurological diseases such as schizophrenia, Alzheimer’s diseases, epilepsy, studying the behaviour of the complex neurological network. It could be also used for studying the evolution of a traumatic brain injury.

Moreover, the apparatus of the invention may be successfully used to investigate the effects of the delivery of a drug, even at different concentrations, on an organ, testing the effects of the drug on all cells of the organ or system involved. Owing to the functional connection through the separating membrane between the cells in the different culture regions, the effect of a perturbation effected on the cells of one culture region is propagated to the cells of another culture region of the culture chamber. The separating membrane connects the at least two culture regions allowing the passage of fluids, like for example a solution, preferably a cell medium, and of the cellular connections through the separating membrane. The separating membrane avoids, at the same time, the passage of cellular bodies through the separating membrane and between the at least two culture regions.

Preferably, the separating membrane is provided with a plurality of pores.

The separating membrane has pores having an average nominal size that is sufficiently small so that during plating the cells do not pass over to the adjoining culture regions. This would allow the desired selective placement of cells in one culture region of the culture chamber. This also avoids the passage of the cells across the separating membrane.

According to a further aspect of the invention it is provided a biocompatible system for creating in vitro cell cultures comprising a supporting substrate and a biocompatible apparatus.

Preferably the biocompatible apparatus is positioned on the supporting substrate to define a culture chamber between the supporting substrate and the apparatus.

The biocompatible apparatus preferably comprises a support structure defining a culture chamber and provided with at least one dividing device for dividing the culture chamber in at least two different culture regions in the culture chamber.

The at least one dividing device is preferably so configured to seal the at least two culture regions to avoid any passage therebetween.

The at least one dividing device is preferably provided with a holding device for holding a separating membrane.

Preferably, the holding device is so configured that the separating membrane is interposed between the at least two different culture regions.

The biocompatible apparatus preferably comprises at least one separating membrane coupled to the holding device and arranged for defining at least two different culture regions in the culture chamber.

The separating membrane is preferably made of a biocompatible material.

The separating membrane is provided with two opposite lateral surfaces facing respectively two different culture regions.

The separating membrane is provided with pores so dimensioned to allow the passage of fluids and/or of cellular connections through the separating membrane and to avoid the passage of cellular bodies through the separating membrane and between the at least two culture regions. The pores are opened at their opposite ends respectively at the two opposite lateral surfaces of the separating membrane so as to allow a connection between the at least two culture regions. The separating membrane puts the two different culture regions in fluid connection allowing the passage of material therebetween. At the same, time the separating membrane impedes the passage of material having certain dimensions between the two culture regions.

Preferably, the apparatus of the invention is configured to be positioned on a supporting substrate so as that the culture chamber is defined between the supporting substrate and the apparatus.

Preferably, the apparatus is so configured to adhere to the supporting substrate so as to define a sealed culture chamber.

In another version, a seal is provided between the apparatus and the supporting substrate to seal the culture chamber and to define a sealed culture chamber avoiding leakages.

The seal is preferably provided for sealing the support structure to the supporting substrate so as to define sealed culture chamber.

The seal is preferably made of PDMS or other biocompatible and sticky materials.

In a version, the supporting substrate comprises an active portion made of MEA (Microelectrode arrays).

Preferably the active portion of MEA is provided on a portion of the supporting substrate. Preferably, the supporting substrate is made of MEA. The supporting substrate may be a Petri dish, or a glass coverslip.

The type of the supporting substrate can be chosen in dependence of the test to be performed and/or the cell culture to be prepared.

Preferably, it is further provided a sealing element between the separating membrane and the supporting substrate.

The sealing element is so configured to allow the passage of fluids, and solutions through the two culture regions and/or the passage of cellular connections between the at least two culture regions and to avoid the passage of cellular bodies between the at least two culture regions. The sealing element is preferably a sealing strip applied between the separating membrane and a supporting substrate.

Preferably, it is provided a further sealing element coupled to the dividing device and arranged for sealing the at least two different culture regions.

Preferably the further sealing element is attached to the dividing device. The further sealing element is arranged to be interposed between the dividing device and the supporting substrate to effectively seal the at least two different culture regions.

The further sealing element is configured to avoid any passage of material and of fluids between the two culture regions.

The presence of the further sealing element allows the at least two culture regions to be sealed and to avoid the passage of the cells’ bodies therebetween.

In this way any fluid connection between the at least two culture regions is allowed only at the separating membrane. The cell cultures could be therefore controlled and manipulated.

The further sealing element is preferably a sealing layer arranged between the dividing element and the supporting substrate. In a version of the apparatus the separating membrane is made of a flexible polymer, like for example PDMS.

In this case, sealed culture regions are obtained also without the provision of the sealing element. In this case the separating membrane acts as sealing element. The provision of the separating membrane made of PDMS further makes the provision of the further sealing elements unnecessary.

Preferably the separating membrane is provided with a plurality of pores extending through the thickness of the separating membrane.

The pores are shaped as channels extending through the thickness of the separating membrane and connecting the two opposite lateral surfaces of the separating membrane. Preferably the pores of the plurality of pores are parallel one to another. In this way parallel paths of the cellular connections between two adjacent culture regions are defined.

Preferably the pores have a rectilinear path. Preferably the pores of the separating membrane are inclined in relation to a lateral surface of the separating membrane, preferably of an angle comprised between about 45 90

Preferably the pores of the plurality of pores are perpendicular to a lateral surface of the separating membrane. Preferably the pores of the plurality of pores are perpendicular to the two opposite lateral surfaces of the separating membrane facing two different culture regions.

Preferably the pores of the plurality of pores are so positioned to be parallel in use to a supporting substrate.

Preferably the pores of the separating membrane spaced along a height of the separating membrane. Preferably the pores of the separating membrane are so positioned that two adjacent pores are equally distanced in the height of the separating membrane.

This disposition of the pores of the separating membrane allows to mimic particular cellular structures that can be found in vivo. For example, considering neuronal cells, the pores of the separating membrane allow the growth of neurites among the different culture regions without letting the cells to migrate or move from one culture region to the another culture region, and also allow the formation of axon fasciculations.

Therefore, the pores of the separating membrane allow a functional and direct contact between the culture regions without allowing migration of cellular bodies therebetween. Preferably, the separating membrane has pores having an average nominal size that is comprised between about 0.1 pm, and about 1mm.

By choosing the desired average nominal size of the pores it is possible to selectively impeding/allowing the passage of fluids and/or of material between the culture regions. Suitable average nominal size of the pores can be chosen based upon specific characteristics of the system, for instance the nature of the cells to be cultured within the culture regions. Such determination is well within the ability of one of ordinary skill in the art and thus is not discussed at length herein.

Preferably, the separating membrane has pores having an average nominal size that is comprised between about 2pm and about 1mm, preferably about 5pm and about 200pm. The choice of pores having an average nominal size in the above indicated ranges allows the passage of fluids between the at least two different culture regions and also the passage of cellular connections through the separating membrane and the two culture regions. Preferably, the separating membrane has pores having an average nominal size that is comprised between about 0.1 p and about 5 pm, preferably between about 0.2 pm and 2 pm.

The choice of pores having an average nominal size in the above indicated range allows the passage of fluids between the at least two different culture regions. Preferably, the separating membrane has pores having a substantially circular section.

In the above indicated range the pores are preferably randomly arranged in the separating membrane.

Suitable porosity for a membrane can be determined based upon specific characteristics of the cell system, for instance the nature of the cells to be cultured within the culture chamber and/or within the at least two culture regions. Such determination is well within the ability of one of ordinary skill in the art and thus is not discussed at length herein. Preferably, the separating membrane has a pore density comprised between about 150 pores/mm² and about 0.2 pores/cm², preferably between about 800 pores/mm² and about 0.1 pores/cm². Adjusting the density of the pores in the separating membrane allows for adjusting the type and/or composition of material flowing between the culture regions.

Preferably the pores of the separating membrane are homogenously arranged on the separating membrane.

Preferably the separating membrane comprises a plurality of pores, wherein the pores of the plurality of pores are parallel one to another and have a nominal dimension comprised 2pm and about 1mm, preferably between about 5 pm and about 200 pm, and a pore density comprised between about 800 pores/mm² and about 1 pore/mm², preferably between about 400 pores/mm² and about 50 pores/mm².

Preferably the separating membrane comprises a plurality of pores, wherein the pores of the plurality of pores are parallel one to another and have a nominal dimension comprised 5pm and about 30mm, and a pore density comprised between about 100 pores/mm² and about 400 pores/mm².

This configuration has been found particularly advantageous in cell cultures for culturing neuronal cells. This allows homogenous connections between the culture regions to be established.

Preferably the separating membrane has pores of almost equal average nominal size.

This allows the cellular connections between the culture regions through the separating membrane to be homogenously established.

Preferably, the pores are arranged regularly on the separating membrane. Preferably, it is provided for obtaining the pores in the separating membrane by means of a LASER radiation.

This allows the dimensions of the pores and/or the position of the pores and/or the pores density to be finely adjusted.

Owing to the use of a laser radiation it is possible for example to define in the separating membrane pores that are parallel one to another and/or regularly spaced in the separating membrane.

It is thus possible to define the properties of the separating membrane and thus to obtain a separating membrane particularly fitted and optimised for a desired cell culture.

It is possible to obtain a membrane allowing the control and repeatability of the cell cultures.

In this way, it is possible to precisely define the dimensions of the pores so as to define the features of the cell cultures and of the connections to be obtained through the membrane.

Preferably the pores of the separating membrane are at least partly filled with ECM. The provision of a filling made of ECM is particularly preferred when the pores have dimensions greater than 5pm.

This further increases the properties of the cell cultures to be obtained. For example, the ECM may allow the grow of the cell connection impeding at the same time the flow of cell bodies through the separating membrane. In this way, it is possible to obtain controlled connections between the culture regions, for example axons connections.

Preferably, the separating membrane has a thickness comprised between 50 pm and 800 pm, preferably a thickness of about 80-350 pm, more preferably between about 90-200 pm. Owing to this feature, it is obtained a separating membrane allowing the growth of axonal processes and providing at the same time an adequate separation of the different culture regions of the cell culture.

Preferably, the separating membrane is a hydrophilic membrane.

This allows a better culture cell to be obtained. The hydrophilicity of the membrane increments the affinity of the cells to the separating membrane and thus promotes the connections of the cells in at least two culture regions.

Preferably, the separating membrane has optical properties. This allows the visual investigation of the morphological properties of the connections, both to ascertain the validity of the apparatus and to have a visual confirmation during the experiments carried out with the apparatus of the invention.

As optical properties, it is intended that the separating membrane can be investigated through optical investigation means like, including, but not limited to, fluorescence microscopy techniques, differential interference contrast microscopy techniques, laser confocal microscopy, multiphoton microscopy, optical coherence tomography, and nuclear magnetic resonance. Preferably, the separating membrane is made of a material that can undergo a sterilisation process.

The sterilization process is preferably chosen in a group comprising UV sterilisation, gamma ray sterilisation, autoclaving, dry oven sterilisation, chemical sterilisation. The separating membrane is preferably made of a biocompatible material chosen in a group comprising cellulose acetate, polydimethylsiloxane (PDMS), polycarbonate, acrylic polymer, polyethersulfone, Hydrosart, etc.

In another version, the separating membrane can comprise a biodegradable material. Through the use of a biodegradable material for the membrane, porosity of the separating membrane can be electively increased during use of the separating membrane.

For example, a non-porous membrane made of biodegradable material can be used which prevents the exchange of culture conditions, or which allows only a very limited fluid passage between the culture regions. During use, as the material is biodegradable, the separating membrane degrades allowing for the exchange of biochemical materials and cellular connections and for the increase of fluid passage between the culture regions.

In a further alternative, the membrane may comprise biodegradable and non- biodegradable material such as a porous non-biodegradable membrane in which the pores are sealed with a biodegradable material or coating. As the biodegradable material or coating is dissolved, the non-degradable porous membrane is revealed.

In this way, the amount of fluid exchange between the culture regions is changed during use.

This may allow for obtaining a system allowing improved investigations of the cell cultures. In a version, a separating membrane made of Cellulose Acetate has been used. In a version a Sartorius™ Cellulose Acetate Membrane Filters has been used. This membrane is made of cellulose acetate, has pore dimension of about 5 pm, a thickness of about 140 pm, and may be subjected to some sterilisation processes like for example autoclaving at 121 °C or 134°C, gamma radiation at 25 kGy, dry oven, ethylene oxide. This membrane allows the flow between the culture regions and it is thermally stable. This membrane is hydrophilic and white in colour.

In a further version, the separating membrane is made of Versapor® Acrylic Copolymer. Hydrophilic acrylic polymer Versapor® membranes on non-woven support have been used. The Hydrophilic acrylic polymer Versapor® membranes are Hydrophilic. The Versapor® Acrylic Copolymer is made of Hydrophilic acrylic polymer Versapor® membrane, has a pore dimension of about 5 pm, a thickness of about 94 pm. This membrane may undergo to sterilisation process like UV or gamma radiation.

Preferably, the separating membrane has a height comprised between 1mm and 10mm. Therefore, it is allowed both the separation of different culture regions and the development of more realistic 3D cell cultures interconnected at different heights.

Preferably, the separating membrane has a length comprised between 1mm and 10mm. The length and height of the separating membrane can be chosen as desired and are adjusted taking into account the features of the apparatus or the cell culture to be prepared. Preferably, the supporting substrate is provided with a coating for facilitating the growth of the cells of the cell culture provided on at least a portion of the supporting substrate.

The provision of the coating allows to enhance the development of the cells in the cell culture in some areas of the culture chamber, and/or of the culture regions.

Preferably, the coating is provided on at least a portion of the face of the supporting substrate facing the culture chamber. Preferably, the coating is made of Poly-L-ornithine.

Preferably, the support structure is made of a biocompatible material, preferably of a biocompatible polymer. The support structure is preferably made of a polymer providing a solid support for the cell culture, for example Formlabs surgical guide biocompatible photopolymer resin, and Formlabs BioMed Clear Resin.

Preferably, the support structure comprises a support body defining a culture chamber having a circular shape.

Circular culture chambers have been proved to be very effective in creating reliable cell culture models. Preferably, the support structure comprises a support body defining a culture chamber having an oval shape. Oval culture chambers have been proved to be effective in creating reliable cell culture models for some type of cells.

Preferably, the support structure comprises a support body defining a culture chamber having a quadrilateral shape, preferably a square culture chamber. It could be chosen a support structure having a polygonal shape, for example hexagonal, heptagonal, octagonal, nonagonal, decagonal, hendecagonal, dodecagonal, or polygonal with a desired number of sides.

The shape of the culture chamber can be selected based on the particular characteristics one of skill in the art desires to replicate. The at least one separating membrane is preferably provided on the at least one dividing device. The at least one dividing device is so configured to avoid any cellular connection between the culture regions in the culture chamber, so that the passage of cellular connections between the two culture regions is allowed only through the separating membrane. Therefore, any undesired exchange of material between the at least two culture regions is avoided.

Preferably, the dividing device is so positioned in the apparatus that the at least two different culture regions have almost the same dimension one with another.

In further version, it is provided a dividing device defining at least two different culture regions having dimensions different one from another. This could be advantageous for some culture cells or test to be performed.

Preferably, if the culture chamber is circular, the dividing device is arranged to define two semi-circular culture regions, or radially to define a plurality of culture regions having the shape of a circular sector. By adjusting the dimensions and/or the shape of the culture chamber and/or of the culture regions it is possible to adjust the properties of the cell cultures obtained. It is possible to optimise the culture conditions for different type of cell cultures.

Preferably, the apparatus comprises a cover lid arranged to be coupled to the support structure. The support structure also allows the position of the cover lid to be stably fixed.

The cover lid preferably comprises the dividing device for dividing the culture chamber in at least two different culture regions. The dividing device is so configured to protrude from the cover lid so that when the cover lid is coupled to the support structure, the dividing device is positioned in the culture chamber and define the at least two culture regions in the culture chamber.

Therefore, the culture regions are effectively separated avoiding undesired exchange of material therebetween.

Preferably the dividing device is integrally formed with the cover lid.

Preferably, the further sealing element is attached to the dividing device and so positioned to seal in use the at least two culture regions to avoid any undesired exchange therebetween.

The dividing device preferably acts as holding device for holding the separating membrane.

Preferably, the cover lid comprises a plurality of cover elements each one of the cover elements being arranged to be coupled to a portion of the support structure.

The cover elements of the plurality of cover elements are provided with coupling means for coupling the cover elements to the respective portion of the support structure. Preferably, each cover element is provided with a respective dividing element.

Preferably, the cover lid comprises two cover elements each arranged to be coupled to a portion of the support structure and provided with a dividing element.

Preferably, the apparatus comprises a locking device for holding the separating membrane in the desired position on the dividing elements. The locking device is also suitable for locking the cover elements one to another when they are coupled to the support structure. This increases the stability of the apparatus of the invention.

The locking device is preferably configured to be coupled to the dividing elements so that the cover elements are mutually locked at the respective dividing element.

The locking device preferably comprises a clip to be applied on to the dividing elements and defining a housing in which the dividing elements may be housed to be mutually locked.

The clip further comprises a head for being grasped by the user.

The locking device allows the separating membrane to be firmly positioned at the dividing device.

Preferably, at least one of the dividing elements is provided with a guide for guiding the insertion of the locking device. Preferably, the locking device comprises a plurality of locking elements to be positioned in different region of the dividing elements for firmly locking the dividing elements. Preferably, the holding device is provided in a peripheral region of the dividing device so that the separating membrane is positioned in a central portion of the dividing device. Preferably, the dividing device is so configured to define a window at which the separating membrane is positioned.

Preferably, the dividing device is so configured that the window is arranged in a central position of the dividing device.

Preferably, the window is so positioned on the dividing device to be arranged in a central position of the at least two culture regions.

Preferably, the apparatus further comprises a fixing device for fixing the cover elements one to another.

Preferably, the fixing device comprises two fixing elements provided at the peripheral region of the cover elements. Preferably, each cover element of the plurality of cover elements is provided with coupling means for coupling the cover lid to the support structure.

Preferably, the coupling means are shape coupling means, and preferably the cover lid has a body defining a housing in which the support structure may be housed.

Preferably, the apparatus is further provided with attaching means for mutually attaching the support structure and the cover lid.

Preferably, the attaching means comprises attaching element and further attaching element provided respectively in the support structure and in cover lid and cooperating for engaging the support structure and the cover element.

The attaching element and the further attaching element are so configured to avoid a relative rotation or sliding of the cover element in relation to the support structure. The attaching element and the further attaching element are so configured to allow the support structure and the cover element to be removably attached.

The support structure comprises a protrusion to be inserted in corresponding hole provided in the cover lid, or vice versa, to attach the cover lid and the support structure. In this way, reciprocal movement between the cover lid and the support structure is avoided, relative rotation is also impeded.

Alternatively, the coupling means provides a compression fitting coupling means. Preferably attaching means allowing the cover lid and the support structure to be attached by pressure and/or twisting action could be used. In this version, a male compression fitting can be configured to sealingly engage the fitting to form a compression fitting.

Preferably, the attaching means comprises a male and female attachment element provided respectively on the supporting structure and on the cover lid, or vice versa.

The support structure and the cover lid may also comprise in a further version both the male and female attaching element on the same or opposing faces.

Preferably, the cover elements comprise coupling elements for mutually coupling the cover elements one to another.

Preferably, the coupling elements are provided at cover portion of the cover elements. Preferably, the coupling elements are shape coupling elements. Preferably, each cover element comprises complementary shaped ends arranged to be mutually coupled.

The coupling elements are so configured that once fully engaged, the cover elements can selectively, and optionally releasably, lock into place.

In a version the support structure comprises peripheral body defining the culture chamber and the dividing device protruding from the peripheral body so as to be arranged internally in the culture chamber and defining at least two different culture regions so configured to seal the at least two culture regions to avoid any passage therebetween. Preferably the apparatus further comprises a limiting device to be inserted in the culture chamber and configured for defining an active culture chamber in the culture chamber in which the cell culture is created.

The limiting device is configured to be crossed by the dividing device so that the separating membrane defines with the limiting device at least two different active culture regions in the culture chamber.

The limiting device limits the dimension of the culture chamber and thus of the culture regions. The limiting device limits the dimension of the culture chamber and thus of the at least two culture regions. The limiting device cooperates with the dividing device and the separating membrane to define at least two active culture regions.

The limiting device is preferably made of PDMS or any other suitable biocompatible material. The limiting device preferably comprises at least two limiting elements arranged to be positioned each one in one culture region and defining an active culture region in each one of the least one culture region.

The limiting elements are preferably coupled to the dividing device so as to define at least two active culture regions in the corresponding at least two culture regions. The limiting elements are preferably suitable for being coupled to the supporting substrate so as to define with the supporting substrate at least two sealed active culture regions.

The limiting elements preferably comprise two indentations to be coupled with the diving device and arranged for housing the dividing elements for coupling the limiting elements to the dividing device. The limiting elements preferably comprise at least two central spaces defining at least two active culture regions.

The central spaces have preferably limited dimensions in relation to the culture chamber so that culture regions of limited dimensions are defined by the limiting device within the culture chamber.

Therefore, in some cases in which culture regions of limited dimensions could be effectively used, it is possible to reduce the quantity of cell material needed for the cell culture and to spare the material necessary for obtaining the cell culture.

Preferably, the limiting elements are so positioned that at least two culture regions of equal or similar shape and/or dimensions are defined by the dividing device.

The dimensions and/or the shape of the culture regions may be chosen basing of the features of the cell culture to be obtained.

It is also possible to better control the properties of the cell cultures.

The limiting device is preferably so dimensioned to define an active culture chamber having a circular shape.

The limiting device is preferably configured to define an active culture chamber having a shape and size so chosen to allow cultivating living cells within the chamber.

Preferably, the limiting device is dimensioned to define an active culture chamber comprised between about 3mm and about 10mm in any cross sectional direction Preferably, the active culture chamber has a circular or oval in cross sectional shape.

In further versions, active culture chamber having polygonal shape like, for example, hexagonal, heptagonal, octagonal, nonagonal, decagonal, hendecagonal, dodecagonal, could be obtained.

The dimensions and shape of the active culture chamber can be chosen by the user based on the particular characteristics which is desired to replicate. The apparatus of the invention defines at least two culture regions and/or at least two active culture regions which are void and in which a cell culture could be plated.

A scaffold could be inserted into the at least two culture regions and/or at least two active culture regions for improving the growth of the cells. Preferably, the system further comprises a scaffold inserted in the culture region and/or in the active culture regions.

The scaffold can be chosen basing in the features of the cell culture to be obtained and/or in the features of the cells to be cultured.

Preferably, the apparatus comprises a plurality of dividing elements for dividing the culture chamber in more than two different culture regions, at least one dividing element being provided with holding means for holding a corresponding separating membrane.

In this way, models mimicking very complex structures may be efficiently obtained. Preferably, at least two dividing elements are provided, preferably each provided with holding means for holding a corresponding separating membrane. In this way, the culture regions are connected at least in couple.

In another version, the apparatus could be provided with one or more dividing element so configured to define three or more culture regions in the culture chamber. The dividing elements are so configured that one or more separating membranes are provided for connecting at least two of the culture regions through the corresponding separating membrane.

Adjusting the number of culture regions defined in the culture chamber allows cell systems having a different complexity may be mimicked.

Adjusting the number of dividing elements and/or of the separating membrane allows different possible interactions between the different culture regions to be mimicked. In the present description and in the attached claims, it is considered that some terms and definitions have, unless explicitly stated the meaning indicated below.

Cell culture is considered here as the process by which cells are grown under controlled conditions, generally outside their natural environment and the system obtained. The term cell culture here refers to the culturing of cells derived from multicellular eukaryotes, especially animal cells. Cell culture here indicates: primary cell culture, cell lines cultures, immortalised cell lines, cultures of organoids, spheroids cultures, tissues cultures, ex vivo cell cultures, etc.

With the term “fluid” it is herein indicated material in fluidic form, like for example a solution, a cell solution, cell medium, physiological solution, and solutes having dimensions allowing the passage into the pores of the separating membrane.

“Cell system” is indicated here as a system containing many cells, of the same type or also of different types one from another. The cell system may comprise different cells of an organ or a tissue.

“Cell connection” indicates in the present specification the means by which the cells communicate. Cell connections are for example neurites for neurons.

“Cell body” indicates in the present specification the body of the cells that contains the nucleus of the cell, the cell body indicates the main part of the cell around the nucleus and containing the nucleus excluding long processes (cellular connections).

With the term “separating membrane” it is herein indicated a material having a thickness, usually ranging between 50 pm and 800 pm, pores with dimensions ranging from 0.1 pm to 1mm.

With the term “perturbation” it is indicated here an event modifying the condition of the cell system. The perturbation may be an external perturbation coming from the external environment or an internal perturbation. A perturbation may be represented for example an electrical stimulation, an acoustic manipulation, a drug. The term “supporting substrate” indicates in the present specification the support on which the cell culture is developed. The supporting substrate may be for example Petri dish, glass coverslips, MEAs, etc.

The definition “optical properties” indicates in this specification that the material can be investigated by means of optical investigation techniques including, but not limited to, fluorescence microscopy techniques, differential interference contrast microscopy techniques, laser confocal microscopy, multiphoton microscopy, optical coherence tomography, and nuclear magnetic resonance.

It is to be understood that this invention is not limited to the specific devices, systems, and/or methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

The following description of the invention is provided as an enabling teaching of the invention in its best, currently known embodiment. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects of the invention described herein, while still obtaining the beneficial results of the present invention. It will also be apparent that some of the desired benefits of the present invention can be obtained by selecting some of the features of the present invention without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations to the present invention are possible and can even be desirable in certain circumstances and are a part of the present invention. Thus, the following description is provided as illustrative of the principles of the present invention and not in limitation thereof.

As used herein, the singular forms "a," "an," and "the" comprise plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a "chamber" comprises aspects having two or more such chamber unless the context clearly indicates otherwise.

Ranges can be expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, another aspect comprises from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. As used herein, the terms "optional" or "optionally" mean that the subsequently described event or circumstance may or may not occur, and that the description comprises instances where said event or circumstance occurs and instances where it does not.

The present invention can be understood more readily by reference to the following detailed description of some example of carrying the invention. The invention will now be further described with reference to the attached Figures in which:

Figure 1 is a schematic view of a system of the invention;

Figure 2 is a schematic view from above of the system of Figure 1 with some details removed for clarity sake;

Fig. 2A is an enlarged view of a detail of Fig. 2 Figure 3 is a schematic perspective view of one embodiment of an apparatus used in the system of Figure 1 with some details removed for clarity sake;

Figure 3A and 3B are enlarged view of details of the Figure 3;

Figure 4 is a lateral view of a detail of the system of Figure 1 ;

Figure 5 is an exploded view of the apparatus of the invention with some details removed for clarity sake; Figure 5A and 5B are view from below of cover elements of the support structure of Figure 4;

Figure 6A-6C represent example of differential interference contrast microscopy images of a cell culture obtained with the system of the invention at DIV 8 ( Day In Vitro (DIV)); Figure 6D and 6E are enlarged views of Figure 6B;

Figure 7 is a schematic representation of the electrical activity of an example of cell culture obtained with the system of the invention;

Figure 8 is an exemplary fluorescent microscopy image of a cell culture obtained with the system of the invention at DIV 17; Figure 9 is a perspective view of a further embodiment of an apparatus of the invention; Figure 10 is a lateral section view of the apparatus of Figure 9 with some parts removed for clarity sake;

Figure 11 is an elevational side view of the apparatus of the Figure 9 with some parts removed for clarity sake; Figure 12 is a enlarged schematic and interrupted view of a separating membrane used in the apparatus of the invention.

In Figures 1-4, it is shown a biocompatible cell culture system 500 for creating in vitro 3D cell cultures 200 according to the invention. The biocompatible cell culture system 500 comprises a biocompatible cell culture apparatus 100, better visible in Figures 3-5, that is suitable for creating in vitro 3D cell cultures 200, better shown in Figures 6A-6C, and a supporting substrate 50. The apparatus 100 is arranged to be positioned on the supporting substrate 50 so as to define a culture chamber 10 for culturing the cells, as explained below.

The apparatus 100 of the invention is suitable for obtaining modular, heterogeneous, 3D cell cultures 200. The apparatus of the invention further allows the development of 3D connections between different populations of the cell culture.

The supporting substrate 50 is made of MEA.

In further version of the apparatus non visible in the Figures, the supporting substrate comprises at least an active portion of MEA arranged to be positioned at the culture chamber 10 and in particular at the active culture chamber 70, as better explained in the following.

The apparatus 100 comprises a support structure 1, better visible in Figures 3- 5, made of a biocompatible material, preferably of a biocompatible polymer. In the version shown, the support structure 1 is made of Formlabs Dental Surgical Guide Resin. The support structure 1 defines a culture chamber 10 in which cells may be cultured, as better explained below. In the version shown, the support structure 1 is a ring 11 so shaped to define a circular culture chamber 10.

In other version of the apparatus not shown in the Figures, the support structure may be shaped to define a quadrilateral culture chamber, preferably a square culture chamber. Culture chamber having any desired shape could be also provided.

The ring 11 is arranged to be positioned on the supporting substrate 50 so that a rest surface 11B of the ring 11 is positioned on the supporting substrate 50.

In this way, a culture chamber 10 is defined between the ring 11 and the supporting substrate 50. The apparatus 100 further comprises a seal, not visible in the Figures, for sealing the support structure 1 to the supporting substrate 50 so as to define a sealed culture chamber 10 and avoid leakages.

The seal is usually made of PDMS (polydimethylsiloxane), a silicone elastomer suitable for biomedical applications. The PDMS is thermally stable, chemically inert, permeable to gases. Moreover, PDMS is transparent, non-fluorescent, biocompatible and nontoxic material. The seal may be continuous, i.e., a layer of PDMS is applied on all the rest surface 11 B of the ring 11, or discontinuous.

In a version, the ring 11 is made of material adhering to the surface of the supporting substrate 50, so as to define with the supporting substrate 50 a sealed culture chamber 10. In this case the seal is not provided.

The ring 11 is provided with a pair of pins 12 protruding from an upper surface 11 A of the ring 11, i.e., the surface opposite to the rest surface 11 B, and arranged to face in use a cover lid 3 of the apparatus 1. The pins 12 are positioned in diametrically opposite positions on the upper surface 11 A. The pins 12 are arranged to attach the support structure 1 to the cover lid 3, as better explained below.

In the version shown, the ring 11 has a thickness d1 of about 2.5mm, a height hi of about 6.00 mm and a diameter D1 of about 25.5 mm.

The support structure 1 has dimensions allowing the support structure 1 to be handled and manipulated by a user as desired. The dimensions of the culture chamber 10 and of the active culture chamber 70 defined by the apparatus 100 can be chosen so as to be adequate for the desired task and/or of the properties to be investigated with the apparatus of the invention.

The apparatus 100 is further provided with a holding device 2 for holding a separating membrane 20, as better explained below. The separating membrane 20 is positioned in the holding device 2 so as to define two different culture regions 10A, 10B in the culture chamber 10, as explained below.

The apparatus 100 further comprises a cover lid 3 arranged to be coupled to the support structure 1 for defining a plurality of culture regions 10A, 10B in the culture chamber 10. The cover lid 3, better visible in Fig. 5, comprises a dividing device 4 protruding from the cover lid 3 so that when the cover lid 3 is coupled to the support structure 1 , the dividing device 4 is positioned in the culture chamber 10 and define the two culture regions 10A, 10B.

The dividing device 4 acts as holding device 2 for holding the separating membrane 20, as better explained below. The cover lid 3 comprises two cover elements 3A, 3B each one being configured to be coupled to a respective portion of the ring 11.

The cover elements 3A, 3B are semi-circular. Each cover element 3A, 3B is provided with an attachment hole 31 arranged to house a corresponding pin 12 provided on the ring 11 for attaching the cover elements 3A, 3B to the support structure 1. The attachment hole 31 and the pin 12 act respectively as attaching element and further attaching element for sealingly engaging the support structure 1 and the cover lid 3.

In other version not shown, the cover elements are provided with different attaching elements arranged for cooperating with corresponding further attaching elements provided in the support structure for attaching the cover elements to the support structure.

In another embodiment not visible in the Figures the support structure and the cover lid are selectively coupled via a compression fitting.

Each cover element 3A, 3B, has a “C” shaped body, better visible in Fig. 5A and 5B, defining a respective housing 32A, 32B in which the ring 11 may be housed. The cover elements 3A, 3B and the ring 11, have a complementary shape so as to define coupling means for coupling the cover element 3A, 3B and the ring 11 one to another.

Each cover element 3A, 3B is provided with coupling elements 33, 34 for mutually coupling the cover elements 3A, 3B one to another.

The coupling elements 33, 34 are provided at the respective peripheral portion 3’, 3” of the cover elements 3A, 3B so that they face one to another and are used for coupling the cover elements 3A, 3B.

The coupling elements 33, 34 are shape coupling elements.

In the version shown, the peripheral portions 3” of a second cover element 3B are shaped so as to define a coupling housing 35 in which the first peripheral portion 3’ of the first cover element 3A is housed, so as to define a shape coupling between the cover elements 3A, 3B.

Each cover element 3A, 3B has an extension greater than the semi-circumference so that at the respective peripheral portions 3’, 3” the first and second cover elements 3A, 3B are mutually superimposed in a corresponding coupling portion 39, as better visible in Fig. 3 and 5.

The apparatus 100 further comprises a pair of fixing elements 37, one of which is better visible in Fig. 3B, arranged to be inserted on the cover elements 3A, 3B for mutually fixing the cover elements 3A, 3B in the desired position.

Each fixing element 37 is “C” shaped and it is configured to be fixed at the coupling portion 39 of the cover elements 3A, 3B so as to fix the cover elements 3A, 3B one to another in the desired position and to avoid any mutual movement between the cover elements 3A, 3B, as clearly visible in Fig. 3. The fixing elements 37 define a fixing housing 38 configured to house the coupling portion 39. The fixing elements 37 are arranged to be fixed to the apparatus 100 from the outer portion, i.e., from the side opposite to the culture chamber 10. In this way, any interference between the fixing elements 37 and the culture chamber 10 is avoided.

Each cover element 3A, 3B is provided with a dividing element 5, 6 extending from the cover elements 3A, 3B configured to protrude into the culture chamber 10. The dividing elements 5, 6 extends almost diametrically in the culture chamber 10. The dividing elements 5, 6 are so positioned to be placed side-by-side one to another when the cover elements 3A, 3B are coupled to the support structure 1.

The dividing elements 5, 6 cooperate one with another for forming the dividing device 4 of the apparatus 100 protruding from the cover elements 3A, 3B and defining two distinct culture regions 10A, 10B in the culture chamber 10. The dividing elements 5, 6 are so configured to extend up to the supporting substrate 50 on which the apparatus 100 is positioned, so that no fluid exchange between the two culture regions 10A, 10B is allowed at the dividing elements 5, 6, as better explained below. The dividing elements 5, 6 are so configured to seal the two culture regions 10A, 10B to avoid any passage therebetween. The dividing elements 5, 6 define a window 40 in correspondence of which the separating membrane 20 may be positioned so that the separating membrane 20 is interposed between the two culture regions 10A, 10B and separates the two culture regions 10A, 10B. Owing to the presence of the separating membrane 20, the culture regions 10A, 10B are mutually connected, as explained below. The window 40 is provided in a central position of the dividing elements 5, 6.

In further version of the apparatus of the invention, not shown in the Figures, the window 40 is positioned peripherally in the dividing elements 5, 6.

In the version shown, the window 40 has a length L2 of about 8mm and a height H2 of about 2 mm. The length L2 and height H2 of the window 40 can be adjusted in dependence of the desires of the user.

The dividing elements 5, 6, are provided with the holding means 2 for holding the separating membrane 20. The separating membrane 20 is positioned between the two dividing elements 5, 6, as a better explained below.

The dividing elements 5, 6 are further provided with guides 90 arranged for guiding the insertion of the locking device 7. The apparatus 100 comprises a locking device 7 for locking the cover elements 3A, 3B one to another when they are attached to the support structure 1.

The locking device 7 is configured to hold the separating membrane 20 in the desired positon in the dividing elements 5, 6. In the version shown, the locking device 7 comprises a pair of clips 8, one of which is better visible in Fig. 3A. Each clip 8 has a body 8A defining a locking house 8B in which the dividing elements 5, 6 may be housed to be mutually locked. Each clip 8 further comprises a head 9 for being grasped by the user for positioning the clip 8 on the dividing elements 5, 6. The clips 8 allow the separating membrane 20 to be firmly held in the desired position in the dividing device 4.

In the versions shown, the clips 8 are arranged to be positioned on the dividing elements 5,6 peripherally in relation to the window 40 so that the window 40 is interposed between the two clips 8. In this case, the window 40 is positioned in a central portion of the dividing elements 5, 6 and the clips 8 are interposed between the ring 11 and the window

40. In this way, the separating membrane 20 is stably held in the window 40.

Additionally, the clips 8 are positioned close to the window 40 so as to increase the stability of the separating membrane 20 in the apparatus 100.

The separating membrane 20 is made of a biocompatible material, for examples cellulose acetate, polydimethylsiloxane (PDMS), polycarbonate, acrylic polymer, polyethersulfone, Hydrosart, etc.

For the separating membrane 20 should be used a biocompatible material that can undergo sterilisation proceedings so as to obtain sterile cell cultures 200 with the system 500 of the invention. With reference to Figure 12 a preferred embodiment of the separating membrane 20 is shown. The Figure 12 is a schematic view of a section of the separating membrane 20. The separating membrane 20 has two opposite lateral surfaces, S, SA arranged to face respectively one of the two culture region 10A, 10B. The separating membrane 20 is provided with a plurality of pores 24 extending between the two opposite lateral surfaces, S, SA and for allowing the fluid connection between the two culture region 10A, 10B.

The separating membrane 20 has two opposite lateral surfaces S, SA arranged to face respectively the two different culture regions 10A, 10B, a base B arranged to be positioned in use in a support substrate 50 and a thickness “d” considered as the distance between the two opposite lateral faces S, SA. The separating membrane 20 comprises a plurality of pores 24 so configured that each pore 24A extends through the thickness d of the separating membrane 20 and is opened at both the two opposite lateral surfaces S, SA. The two lateral surfaces S, SA are parallel one to another.

The pores 24A of the plurality of pores of the separating membrane 20 are so dimensioned to allow the selective passage of material between the two culture regions. The separating membrane 20 puts the two culture regions in fluid connection allowing the passage of fluid and of the nutrient supply and it allows biochemical communication between the two culture regions 10A, 10B.

The separating membrane 20 is so configured to connect the culture regions 10A, 10B to allow the passage of only the desired material between the culture regions 10A, 10B only at the pores 24A.

The separating membrane 20 is so configured to connect the culture regions 10A, 10B to allow the passage of only the desired material between the culture regions 10A, 10B. In particular, the separating membrane 20 is so configured to allow the passage of cell connections 22 through the separating membrane 20, as better discussed with reference to Fig. 8, and to avoid the passage of cell bodies 23 through the separating membrane. The separating membrane 20 is provided with pores 24A so dimensioned to allow the passage of cell connections 22 through the pores 24A and thus through the separating membrane 20 and to avoid the passage of cell bodies 23 through the pores 24A and the separating membrane 20 and thus between the at least two culture regions 10A, 10B.

The pores 24A have an average nominal dimension of about 5 pm.

The pores 24A are arranged in the separating membrane 20 so that the separating membrane 20 has a density of the pores, indicated as the number of pores per square millimetre, comprised between 150 pores/mm² and 0.2 pores/cm². The separating membrane 20 has a thickness “d” comprised between 50 pm and 800pm, preferably a thickness “d” of about 100 pm, and a height H of about 2.00 mm, and a length L of about 8.00 mm. Preferably the separating membrane 20 has a height H >= 1mm. Preferably the separating membrane 20 has a length L comprised between 1mm and 10mm. The actual length and height of the separating membrane can be chosen by the user on the basis of the features of the apparatus or of the assigned task.

The height H of the membrane is considered in a direction perpendicular to a supporting substrate.

As better visible in Fig. 12, the pores 24A of the separating membrane 20 are parallel to one another so as to define parallel paths of the cellular connections between the culture regions 10A-10B.

The pores 24A are perpendicular to the lateral surfaces S, SA of the separating membrane 20. The pores 24A of the separating membrane 20 are parallel in use to the supporting substrate 50.

The separating membrane 20 has optical properties so that it can be investigated through optical investigating techniques. The separating membrane 20 can be transparent, or it could be made of a material that does not disrupts the optical path. Additionally, the separating membrane 20 can comprise a material that affects the transmission of physical parameters, but optical transmission as well.

Thus, contemplated herein are separating membranes in which the separating membrane only allows the transmission of certain wavelengths of light to pass from one side of the membrane to the other or excludes specific wavelengths of light.

The apparatus 100 further comprises a limiting device 60, better visible in Fig. 2A, to be inserted in the culture chamber 10 and configured for defining in the culture chamber 10 an active culture chamber 70 in which the cell culture 200 is created. The limiting device 60 limits the dimension of the culture chamber 10 and thus of the culture regions, as explained below.

The limiting device 60 is made of PDMS or any other suitable biocompatible material.

The limiting device 60 comprises two limiting elements 60A, 60B arranged to be positioned each one in one culture region 10A, 10B. The limiting elements 60A, 60B are suitable for being coupled to the supporting substrate 50.

The limiting elements 60A, 60B are suitable for being coupled to the dividing device 4 so as to define two active culture regions 70A, 70B therewith, as explained below.

The limiting elements 60A, 60B comprise two indentations 61 A, 61 B each to be coupled with the diving elements 5, 6 and arranged for housing the dividing elements 5, 6 and two central spaces 62A, 62B defining two active culture regions 70A, 70B of the system 500. The two indentations 61 A, 61 B are arranged for coupling with the dividing elements 5, 6 and/or with supporting membrane 20 and also furnishes an additional anchorage so as to increase the stability of the apparatus 100 of the invention. The central spaces 62A, 62B have limited dimensions in relation to the culture chamber 10 so that culture regions 70A, 70B of limited dimensions are defined by the limiting device 60 within the culture chamber 10.

Therefore, in some cases in which culture regions of limited dimensions could be effectively used, it is possible to reduce the quantity of cell material needed and to spare the material necessary for obtaining the cell culture 200.

The limiting device 60 is so dimensioned to define an active culture chamber 70 having a circular shape and a diameter D* of about 5 mm.

The active culture chamber 70 can generally be of a shape and size so chosen to allow to cultivate living cells within the chamber. The shape and the dimension of the active culture chamber are so chosen to maintain a flow of material throughout a cellular construct held in the active culture chamber.

In a preferred embodiment, the active culture chamber 70 can be designed to accommodate a biomaterial scaffold to create a 3D environment, while ensuring adequate nutrient flow throughout a cellular construct held in the active culture chamber 70.

The system 500 may comprise a biomaterial scaffold, not visible in the Figures, positioned in the active culture chamber 70 arranged for facilitating the formation of a 3D environment and ensuring adequate nutrient flow throughout a cellular construct held in the active culture chamber 70. The limiting elements 60A, 60B are so dimensioned that the central spaces 62A, 62B are defined at the separating membrane 20.

The active culture regions 70A, 70B are mutually interconnected by the separating membrane 20 so that a selective exchange of material is allowed between the two active culture regions 70A, 70B. The cell culture system 500 further comprises a sealing element, not visible in the Figures, arranged between the separating membrane 20 and the supporting substrate 50. The sealing element is chosen in dependence of the properties of the separating membrane so that the same material flows through the separating membrane and the sealing element. The sealing element may allow the passage of fluids therethrough, the passage of solutions between the two culture regions and/or the two active culture regions, the passage of cellular connections between the two culture regions and/or the two active culture regions and avoid the passage of cellular bodies between the two culture regions. The cell culture system 500 further comprises a further sealing element, not visible in the Figures, arranged between the dividing element 4 and the supporting substrate 50 and arranged for sealing the two culture regions avoiding any passage of fluid therebetween. For assembling the system 500 of the invention it is provided for placing the ring 11 on a supporting substrate 50 and sealing the ring 11 and the supporting substrate 50 by means of a seal. Some PDMS is applied between the ring 11 and the supporting substrate 50 and then cured in an oven for obtaining the seal. For example, it may be cured in an oven at 120°C for at least 5 minutes or at lower temperature for a more prolonged period of time, for example 70-80°C for at least 10 minutes.

A second layer of PDMS may be applied on an outer side of the ring 11 , i.e., on the face opposite to the culture chamber 10, to obtain a stronger seal.

Also the second layer of PDMS is cured in an oven, for example at 120°C for at least 5 minutes or at lower temperature for a more prolonged period of time, for example 70- 80°C for at least 10 minutes.

Once the ring 11 is firmly coupled to the supporting substrate 50, the apparatus 100 is assembled as described below. A separating membrane 20 is provided. Preferably the separating membrane 20 is obtained by cutting a membrane having desired dimensions from a sheet of film material. A separating membrane 20 having dimensions greater than the window 40 is provided. This allows to make the positioning of the separating membrane 20 easier and to avoid a wrong positioning of the separating membrane 20 that would imply that a portion of the window 40 is void of the separating membrane 20.

The separating membrane 20 is inserted between the dividing elements 5, 6. The cover elements 3A, 3B are assembled and positioned on the ring 11. Then the fixing means 37 are positioned on the cover elements 3A, 3B and the clips 8 are inserted on the dividing elements 5, 6 at the guide 90.

A sealing layer is applied under the dividing elements 5, 6 to seal the dividing element at the supporting substrate 50, so as to seal the two culture regions 10A, 10B and to avoid leakages therebetween.

The sealing layer may be formed in PDMS. The sealing layer is positioned as described below.

The cover elements 3A, 3B are assembled, then the fixing means 37 are positioned on the cover elements 3A, 3B and the clips 8 are inserted on the dividing elements 5, 6. The sealing layer is applied under the dividing elements 5, 6, and then the cover elements 3A, 3B are attached to the ring 11, and the dividing elements 5, 6 are attached to the supporting substrate 50. The sealing layer is then cured, for example in a dry oven at 120°C for at least 5 minutes, or at 70-80°C for 10 minutes or more. The sealing layer acts thus as further sealing element for sealing the dividing elements 5, 6 to the supporting substrate 50

Afterwards, the clips 8 and the fixing means 37 are removed from the dividing elements 5, 6 in order to insert the separating membrane 20 as explained below. A separating membrane 20 having dimensions greater than the window 40 is provided, preferably by cutting it from a film material. This allows to make the positioning of the separating membrane 20 easier and to avoid a wrong positioning that would imply that a portion of the window is void of the separating membrane 20. The membrane is inserted between the dividing elements 5, 6. The cover elements 3A, 3B, are so assembled, then the fixing means 37 are positioned on the cover elements 3A, 3B and the clips 8 are inserted on the dividing elements 5, 6.

Once the separating membrane 20 is inserted, and the cover lid 3 is assembled, the limiting elements 60A and 60B are inserted in the culture regions 10A and 10B to form the active culture regions 70A and 70B and thereafter the apparatus 100 is sterilised.

The supporting substrate 50, the ring 11, the limiting device 60 and the sealing layer if present, are sterilised, for example in a dry oven at 120°C for 2 hours. The cover lid 3 and the separating membrane 20 are also sterilised, for example by autoclave or by UV irradiation 20 minutes of exposure on each side, depending on the characteristics of the membrane.

After sterilisation, a coating is applied on the supporting substrate 50 in correspondence of the active culture chamber 70. The coating is made with Poly-L-ornithine, an adhesion factor that facilitates neuronal growth, that was kept overnight and then washed before proceeding with the following steps. Afterwards, the cover lid 3 is applied on the ring 11.

If necessary, before applying the cover lid 3 to the ring 11, a sealing strip, not visible in the Figures, is applied under the separating membrane 20 to form sealing element for sealing the separating membrane 20 and the supporting substrate 50.

The sealing element allows any leakage under the membrane 20 between the two culture regions 10A, 10B to be avoided. The sealing strip is preferably made of ECM gel. The separating membrane 20 is fixed to the supporting substrate 50 by means of the sealing strip made of ECM gel. ECM gel is a gelatinous protein mixture secreted by Engelbreth-Holm-Swarm (EHS) mouse sarcoma cells that mimics the extracellular environment and is used as a basement membrane matrix for culturing cells.

The provision of the ECM gel should also prevent soma movement to some extent, thus by placing a sealing strip of ECM gel on the supporting substrate 50 it was created a tunnel were only neurites could pass. After having applied the sealing strip, the cover lid 3 is applied on the ring 11, and the system 500 is placed in an incubator for 5 min to allow the polymerisation process of the ECM gel to occur. From this step forward, the system 500 is stored in the incubator at constant temperature (37°C), humidity (95%) and C0₂ level (5%) and it is ready for plating cells.

In Figure 9-11 a further embodiment of the apparatus of the invention is shown, in which parts corresponding to the apparatus shown in Figures 1-5 are indicated with the same reference numbers followed by an apex and not described in detail in the following-.

The apparatus 100’ comprises a support structure T shaped as a ring 1T and defining a culture chamber 10’ in which cells may be cultured, having a circular shape.

The ring 11 ’ is arranged to be positioned on a supporting substrate so that a rest surface 1 TB of the ring 1 T is positioned on the supporting substrate. The culture chamber 10’ is thus defined between the ring 1T and the supporting substrate.

Also in this case the apparatus 100’ further comprises a seal, not visible in the Figures, for sealing the support structure T to the supporting substrate so as to define a sealed culture chamber 10 and avoid leakages. The apparatus 100’ is further provided with a holding device 2’ for holding a separating membrane 20’, as better explained below.

The separating membrane 20’ is positioned in the holding device 2’ so as to define four different culture regions 10Ά, 10’B, 10’C, 10’D in the culture chamber 10’, as explained below. In this case the separating membrane 20’ is shaped like a cross with four arms 20Ά. In the version shown the arms of the separating membrane 20’ have substantially the same length, nevertheless in some versions a separating membrane 20’ having arms of different length could be provided.

Each arm 20Ά of the separating membrane 20’ has two opposite lateral surface S’, S’A arranged to face respectively two different adjacent culture regions 10Ά-10Ό, a base B’ arranged to be positioned in use in a support substrate 50 and a thickness d’ considered as the distance between the two opposite lateral surfaces S’, S’A. The two lateral surfaces S’, S’A are parallel one to another.

The separating membrane 20’ comprises a plurality of pores 24’ so configured that each pore 24Ά extends through the thickness d’ of the separating membrane 20’ and is opened at both the two opposite lateral surfaces S’, S’A.

Also in this case the pores 24Ά fluidly connect two adjacent culture regions 10Ά-10Ό. The pores 24Ά of the plurality of pores 24’ are parallel to one another so as to define parallel paths of the cellular connections between the culture regions 10A’-10’D. The pores 24Ά are perpendicular to the lateral surfaces S’, S’A of the separating membrane 20’. The pores 24Ά of the separating membrane 20’ are arranged to be parallel in use to a supporting substrate on which the apparatus 100 is positioned. Moreover the pores 24Ά are equally spaced in the separating membrane 20’.

The apparatus 100’ further comprises a cover lid 3’ arranged to be coupled to the ring 1 T for defining the plurality of culture regions 10Ά, 10’B, 10’C, 10’D in the culture chamber 10

The cover lid 3’comprises a dividing device 4’ protruding from the cover lid 3’ so that when the cover lid 3’ is coupled to the support structure T, the dividing device 4’ is positioned in the culture chamber 10’ and define the four culture regions 10Ά-10Ό. The cover lid 3’ may be made of a single piece or may comprise, as in the version shown, a plurality of cover elements 3Ά, 3’B, 3’C, 3’D each one being configured to be coupled to a respective portion of the ring 1 T.

This facilitate the assembly of the apparatus 100’.

In the version shown the cover lid 3’ comprises four cover elements 3Ά-3Ό having each the shape of a circular sector and configured to be coupled to a respective portion of the ring 1 T.

The ring 1T and the cover elements 3Ά-3Ό are provided with respective attaching element and further attaching elements for sealingly engaging the support structure T and the cover lid 3’. Each cover element 3Ά-3Ό is provided with coupling elements for mutually coupling the cover elements 3Ά-3Ό one to another.

The dividing device 4’ comprises four dividing arms 4T acting as holding device for holding the separating membrane 20’ and so positioned in the ring 1T to define culture regions having the same shape and dimension. Nevertheless in further versions not shown the dividing arms may be so configured that culture regions 10Ά-10Ό of different shape and/or dimensions are defined.

Each dividing arm 4T comprises a first and a second dividing element 5’, 6’ positioned to be placed side-by-side one to another when the cover elements 3Ά-3Ό are coupled to the support structure T. The dividing elements 5’, 6’ cooperate one with another for forming the dividing device 4’ of the apparatus 100’ protruding from the cover elements 3Ά-3Ό and defining four distinct culture regions 10Ά-10Ό in the culture chamber 10’.

The dividing elements 5’, 6’ are so configured to extend up to the supporting substrate on which the apparatus 100’ is positioned, so that no fluid exchange between the culture regions 10Ά-10Ό is allowed at the dividing elements 5’, 6’. The dividing elements 5’, 6’ seal the culture regions 10Ά-10Ό to avoid any passage therebetween.

The first and second dividing element 5’, 6’ of each dividing arm 4T are fixed at one end thereof at the cover lid 3’ and comprise a free end 5Ά, 6Ά that is opposite to the cover elements 3Ά-3Ό and protrudes into the culture chamber 10’. The free ends 5Ά, 6Ά of the first and second dividing elements 5’, 6’ are provided in a central part of the culture chamber 10’ and are mutually spaced apart. In this way, it is defined into the culture chamber 10’ a central portion 10” void of the dividing arms 4T.

The separating membrane 20’ is fixed at the free ends 5Ά, 6Ά of the first and second dividing element 5’, 6’ of each dividing arm 4T, so that the separating membrane 20’ is provided in the central portion 10” of the culture chamber 10’.

In this case therefore four distinct culture regions 10Ά-10Ό are defined, in which each culture region 10Ά-10Ό is connected with the respective two adjacent culture regions by means of the separating membrane 20’.

Also in this case a limiting device could be inserted in the in the culture chamber 10’ for defining in each culture region 10Ά-10Ό of the culture chamber 10 an active culture chamber in which a cell culture is created.

In other versions, not shown in the Figures, the apparatus may comprise several dividing elements dividing the culture chamber in more than two different culture regions. In this case, at least one dividing element is provided with holding means for holding a corresponding separating membrane. In this case the plurality of regions of the culture chamber may be all coupled one with another through a separating membrane, or at least two of the culture regions are mutually coupled through a separating membrane, or each culture region is coupled through a separating membrane to the adjoining culture regions. In this way, in vitro models of very complex assemblies may be efficiently obtained. Changing the number of culture regions or the connections between the culture regions allow different complex structures to be mimicked

In another version, the apparatus could be provided with dividing elements so configured to define three or more culture regions in the culture chamber. The holding means may be positioned in the dividing element so that one or more separating membranes are provided for connecting at least two of the culture regions through the membrane. The dividing elements may extend radially in the culture chamber.

In further versions of the apparatus not shown in the Figures, the holding device may be provided on the ring and protruding in the culture chamber.

EXAMPLES Example 1

A system 500 has been prepared comprising a support structure 1 and a separating membrane 20 and a supporting substrate 50 made of MEA.

The separating membrane was made of Cellulose Acetate, available as Sartorius™ cellulose Acetate Membrane The membrane has pores having an average nominal size of about 5 pm, a thickness D of about 140 pm. It is hydrophilic and white in colour.

The support structure 1 is a ring 11 made of a biocompatible resin having a height of 6.00 mm, a thickness of 2.25 mm, and internal diameter of 25.50 mm and an external diameter of 30.00 mm. The ring 11 is provided with a couple of pins having a diameter of 1.2 mm and a height of 1.00 mm. The cover lid 3 is made of a biocompatible resin and consists of two distinct cover elements 3A, 3B with complementary peripheral ends 3, 3”, to form a fixed joint, preventing their movement to some extent and ensuring vertical alignment.

The dividing elements 5, 6 define a window 40 having a height of 2 mm and a length L2 of 8 mm and are configured to be so positioned that the respective windows correspond one to another. The dividing elements 5, 6 have a maximum height of 7 mm and a thickness of 1 mm. The dividing elements 5, 6 are provided with guides 90 arranged for inserting and holding the separating membrane 20. The guides have a width of 1.2 mm. The separating membrane 20 is held between the two dividing elements 5, 6.

Example 2 A system has been prepared as in the Example 1 , except that a separating membrane 20 made of hydrophilic acrylic polymer, available as Versapor^R on nonwoven support has been used. The separating membrane has pores having an average nominal size of about 5 pm, a thickness D of about 94 pm. It is hydrophilic and white in colour.

Once inserted, the membrane was sterilised with UV radiation together with the upper part of the apparatus.

Cell cultures

Cell cultures have been prepared using the procedures for preparing cell cultures for experimental purposes in accordance with the European Animal Care Legislation (2010/63/EU), and in compliance with the legislative decree of the Ministry of Health (DL 116/1992) and the guidelines of the University of Genova (Prot. 75F11.N.6JI, 08/08/18), in order to reduce the number of animals needed for testing and their suffering.

Cell cultures of dissociated cortical and hippocampal neurons of embryonic rats, at gestational day 18 have been used. Briefly, the cerebral cortices/hippocampi of embryos were dissected and underwent a first stage of dissociation by enzymatic digestion in

Trypsin solution 0.125% and DNAse solution for 20 min at 37°C. The action of the trypsin enzyme is then blocked by washing in culture medium containing foetal bovine serum (FBS). The enzymatic dissociation was followed by a mechanical one thanks to the use of fine-tipped Pasteur pipette. The resulting tissue was resuspended in Neurobasal medium supplemented with 2% B-27, 1% Glutamax-I and 1% Pen-Strep solution. Neurons were plated on the apparatus prepared as in Example 1 or 2. Neurons are plated on the active portion of the supporting substrate (either coverslip or MEA depending on the experiment) at one of the two active culture regions 70A, 70B.

The electrophysiological results relative to n = 52D hippocampal networks and n = 1 3D culture, are presented below, where n represent the number of cell culture. In the 2D configuration, the plating procedure for plating the neuron cells on the system consisted of placing the cells on one of the active culture region 70A, 70B defined in the culture chamber 10.

For seeding, a 20 pi drop of the cell suspension was placed in one active culture region 70A. Considering 1500 cells/mm² and a total surface area of 30 mm² (area of each active culture region 70A, 70B plus area of the separating membrane 20 in contact with the cells and lateral surface of the limiting device 60), the cells were suspended at the concentration of 2250 cell/mI.

Neurobasal medium has been added 1 hour after the plating procedure and the devices were stored in the incubator. At DIV 5, half of the medium was replaced with BrainPhys medium, supplemented with a 2% NeuroClut SM1, 1% Glutamax, and 1% PenStrep solution. For the maintenance of the cell cultures, a partial medium change (50%) was performed once a week. Glia proliferation was not prevented by adding anti-mitotic drugs, as it plays an essential role in the nervous system.

In the 3D configuration, a first layer of neurons, which acts as the interface between the recording electrodes of the MEA and the 3D population, has been plated directly onto the area of the supporting substrate 50 inside one culture region 70A or 70B. For the realization of the first cell monolayer the protocols for cell plating, described above for the 2D configuration, were followed, with the adding of the following procedure to create the 3D culture before adding the culture medium (Neurobasal). The 3D assembly was built over the monolayer, 1 hour after its plating using the ECM gel, following the protocol described below.

Considering that ECM gel will undergo thermally activated polymerization when brought to 20-40°C, the following steps were followed.

The day before cell plating, a set of sterile vials, a set of sterile gloves, some pipettes and vial holders have been put in the refrigerator and some ice has been also prepared.

The day of the experiment, The ECM gel has been kept below 10°C by using the pre cooled materials indicated above and working on ice. The ECM Gel has been diluted with Dulbecco's Modified Eagle's Medium (1 :2 ratio) and the cells have been added to the solution at the desired concentration. Then, cells were plated onto the monolayer and stored in the incubator at constant temperature (37°C), humidity (95%) and C0₂ level (5%).

Different experiments were carried out to confirm the efficacy of the apparatus 100 in creating a cell culture system 500 that allows to create 3D, modular and heterogeneous cell cultures and that supports the development of connections between the different sub- populations in 3 dimensions.

Firstly, the apparatus 100 was coupled to coverslips as supporting substrate 50 to allow visual inspection via microscope techniques. Following the procedures described in Example 1 and 2, the cell cultures 200 were plated in one of the active culture regions 70A or 70B, to verify if the cell bodies 23 were kept in the designed active culture region 70A or 70B. Figure 6 shows some images obtained with DIC microscopy techniques. Neuronal cells were plated into one active culture region 70A. A magnification of the active culture region 70A is shown in Fig. 6E, and a magnification of the active culture region 70B void of cells, i.e. that was not plated with cells is shown in Fig. 6D. In Fig. 6E, the cell bodies 23 are clearly visible in the plated active culture region 70A, whilst Fig. 6D clearly show that the active culture region 70B is empty. Figs. 6A-C, show different magnifications of both active culture chambers 70A and 70B. In particular, they show a neat division between the plated active culture region 70A and the empty one 70B. This evidence demonstrates that the cell culture system 500 was capable of preventing migration of the cell bodies 23 from the active culture region in which they were plated 70A to the adjoining active culture region 70B. This achievement is maintained for prolonged periods of time (more than 3 weeks).

To further support these observations, the electrophysiological spontaneous activity of n=6 hippocampal cultures (of which n=5 were in a 2D and n=1 in a 3D configuration) plated on the supporting substrate 50 made of MEAs coupled to the apparatus 100 was recorded.

The MEAs presented 120 electrodes for the recording of the electrophysiological signal. The cell cultures 200 were plated in the active culture region 70A, to verify if the cell bodies 23 were kept in the active culture region 70A in which the cells are plated. The cell cultures 200 were left in the incubator to mature and recorded at DIV (Day In Vitro)17 for 15 minutes.

Figure 7 shows a representative example of raw data recorded from the MEAs. Each rectangle shows the recorded signal from one of the electrodes. The position of the electrode in the active culture chamber 70 is maintained in the grid where the recorded data is displayed. This means that the data shown in the upper left rectangle was recorded from the upper left electrode in the active culture chamber 70. In each rectangle, the x-axis displays the time, whereases the y-axis displays the potential recorded at the site.

In the graph of Figure 7 there are reported a plurality of boxes 700, the boxes on the right of the graph corresponds to the electrodes positioned in the active culture region 70A in which the cell culture is plated, whilst the boxes on the left of the graph corresponds to the electrodes positioned in the active culture region 70B void of cell culture.

In Figure 7, it is clearly shown that only electrodes on the right recorded electrophysiological activity, whereases the electrodes in the active culture region 70B do not record any activity. This confirms from a functional point of view that the cultured cells remained confined only in the plated active culture region 70A.

This also demonstrates that the apparatus 100 is able to support the viability of the cell cultures 200 for prolonged periods of time and that the cells are able to display strong and sustained activity. This feature was achieved both for the 2D and 3D cultures. Finally, it was verified that the separating membranes 20 promote neurites, i.e. cell connections 22, outgrowth through its pores. Following the procedures described in Example 1 and 2, the cell cultures 200 were plated in the active culture region 70A, leaving the active culture region 70B empty as control. Upon reaching a mature stage (DIV 17), the established cell network was inspected via fluorescence microscope techniques. In particular, cells were stained with NeuroFluor, a membrane-permeable fluorescent probe that selectively labels live primary and hPSC-derived neural progenitor cells without fixation. In this way, it was possible to verify if the neurites (cell connections 22) were able to cross over to the adjoining control active culture region 70B.

Figure 8 shows a magnification of the neuritic arborisation (cell connections 22) of a neuronal cell. It may clearly be seen that the cell connections 22 depart from the cell body 23 in active cell culture region 70A. The cell connections 22 pass through the separating membrane 20, represented in dashed lines in Figure 8, and reach the empty control active culture region 70B.

This confirms that the established network of cell connections 22 was able to spread through the separating membrane 20 and to reach the empty active culture region 70B. this also confirms that on the contrary the cell body 23 do not spread through the active culture regions and remain in the active culture region in which they are plated.

It is thus demonstrated that the invention reaches the proposed object and allows many advantages to be obtained.

Claims

1. Biocompatible apparatus (100; 100’) for creating in vitro cell cultures comprising: a support structure (1; 1’) defining a culture chamber (10; 10’) and provided with a dividing device (4, 5, 6; 4’, 41’, 5’, 6’) being positioned to define at least two different culture regions (10A, 10B; 10Ά, 10’B, 10’C, 10’D’) in the culture chamber (10; 10’) and so configured to avoid any fluid passage between the at least two culture regions (10A, 10B; 10Ά, 10’B, 10’C, 10’D’), the dividing device (4, 5, 6; 4’, 41’, 5’, 6’) being provided with a holding device (2; 2’) for holding a separating membrane (20; 20’) so that the separating membrane (20; 20’) is interposed between the at least two different culture regions (10A, 10B; 10Ά, 10’B, 10’C, 10’D’), and at least one separating membrane (20; 20’) coupled to the holding device (2; 2’) made of a biocompatible material and being provided with a plurality of pores (24, 24’), the pores (24, 24A; 24’, 24’ A) of the plurality of pores (24, 24’) being so dimensioned to allow the passage of fluids and/or of cellular connections (22) therethrough and to avoid the passage of cellular bodies (23) through the separating membrane (20; 20’) and between the at least two culture regions (10A, 10B; 10’ A, 10’B, 10’C, 10’D’) and wherein the pores (24, 24A; 24’, 24’ A) of the plurality of pores (24, 24’) are parallel one to another.

2. Apparatus according to claim 1, wherein the pores (24, 24A; 24’, 24Ά) have an average nominal dimension comprised between about 0.1 pm, and about 1mm, preferably between about 2pm and about 1mm, more preferably between about 5 pm and about 200 pm .

3. Apparatus according to any one of claims 1-2, wherein the separating membrane (20; 20’) has a pore density comprised between about 150 pores/mm² and about 0.2 pores/cm², preferably between about 800 pores/mm² and about 0.1 pores/cm²

4. Apparatus according to any one of claims 1-3, wherein the pores (24, 24A; 24’, 24Ά) of the separating membrane (20; 20’) are regularly arranged on the separating membrane (20; 20’).

5. Apparatus according to any one of claims 1-4, wherein the separating membrane (20; 20’) has pores (24, 24A; 24’, 24Ά) having almost equal average nominal size.

6. Apparatus according to claim 1, wherein the separating membrane (20; 20’) has pores (24, 24A; 24’, 24Ά) having an average nominal dimension comprised between about 0.1 pm and about 5pm, preferably between about 0.2 pm and 2 pm.

7. Apparatus according to any one of the preceding claims wherein the separating membrane (20; 20’) comprises two opposite lateral surfaces (S, SA; S’, S’A) arranged to face respectively two different adjacent culture regions (10A-10B; 10Ά-10Ό), wherein each pore (24A; 24’ A) of the plurality of pores (24; 24’) extends through the thickness (d; d’) of the separating membrane (20; 20’) and is opened at both the two opposite lateral surfaces (S, SA; S’, S’A).

8. Apparatus according to the preceding claim wherein the pores (24A; 24’ A) of the plurality of pores (24; 24’) are arranged perpendicularly to the lateral surfaces (S, SA; S’, S’A) of the separating membrane (20; 20’).

9. Apparatus according to the any one of the preceding claim wherein the pores (24A; 24’ A) of the plurality of pores (24; 24’) are regularly spaced along a height (H; H’) of the separating membrane (20; 20’).

10. Apparatus according to any one of claims 1-9, wherein at least some of the pores (24, 24A; 24’, 24Ά) of the separating membrane (20; 20’) are at least partly filled with ECM.

11. Apparatus according to any one of claims 1 to 10, wherein the separating membrane (20; 20’) has optical properties to allow the investigation of the biological component by means of microscopy tools.

12. Apparatus according to any one of claims 1 to 11, wherein the separating membrane (20; 20’) is made of a hydrophilic material, chosen in a group comprising cellulose acetate, polydimethylsiloxane (PDMS), polycarbonate, acrylic polymer, polyethersulfone, Hydrosart.

13. Apparatus according to claim any one of claims 1 to 12, wherein the separating membrane (20; 20’) is made of PDMS.

14. Apparatus according to claim any one of claims 1 to 13, wherein the separating membrane (20; 20’) has a thickness (d; d’) comprised between 50 pm and 800 pm, preferably a thickness of about 80-350 pm, more preferably between about 90-200 pm.

15. Apparatus according to any one of claims 1 to 14, wherein the support structure (1; 1’) is made of biocompatible material, preferably of a biocompatible polymer.

16. Apparatus according to any one of claims 1 to 15, wherein the support structure (1; 1’) is so shaped to define a culture chamber having substantially circular shape, or ovoidal shape, or a polygonal culture chamber, preferably a square culture chamber.

17. Apparatus according to any one of claims 1 to 16, and further comprising a cover lid (3; 3’) arranged to be coupled to the support structure (1; 1’).

18. Apparatus according to claim 17, wherein the cover lid (3; 3’) comprises a dividing device (4) protruding from the cover lid (3; 3’) so that when the cover lid (3; 3’) is coupled to the support structure (1; 1’), the dividing device (4) is positioned in the culture chamber (10; 10’) and define the at least two culture regions (10A, 10B; 10’ A, 10’B, 10’C, 10’D’) in the culture chamber (10; 10’), the dividing device (4) preferably acting as holding device (2; 2’) for holding the separating membrane (20; 20’).

19. Apparatus according to claim 15, wherein the dividing device (4) is so configured to define a window (40) in which the separating membrane (20; 20’) is positioned.

20. Apparatus according to any one of claims 17 to 18, wherein the cover lid (3; 3’) is provided with coupling means (31) for coupling the cover lid (3; 3’) to the support structure (1; 1’), the support structure being preferably provided with further coupling means (12) configured to couple with the coupling means for mutually coupling the support structure (1; 1’) and the cover lid (3; 3’).

21. Apparatus according to any one of claims 16 to 20, wherein the cover lid (3; 3’) comprises at least two cover elements (3A, 3B; 3Ά-3Ό) each one being configured to be coupled to a respective portion (1A, 1B) of the support structure (1; 1’).

22. Apparatus according to claim 21, wherein the at least two cover elements (3A, 3B; 3Ά-3Ό) are provided with respective coupling means for coupling the cover elements (3A, 3B; 3Ά-3Ό) to the respective portion of the support structure (1; 1’), the coupling means preferably comprises a housing (32A, 32B) defined in the corresponding cover elements (3A, 3B; 3Ά-3Ό) and arranged for housing the respective portion of the support structure (1 ; 1’).

23. Apparatus according to claim 21 , or 22 wherein the at least two cover elements (3A, 3B; 3Ά-3Ό) are provided with respective attaching element (31) the support structure (1; 1’) being provided with further attaching element (12) cooperating with the attaching element (31) for attaching the cover elements (3A, 3B; 3Ά-3Ό) and the support structure (1; 1’).

24. Apparatus according to any one of claims 21 to 23, wherein the at least two cover elements (3A, 3B; 3Ά-3Ό) are provided with coupling elements (33, 34) for mutually coupling the cover elements (3A, 3B; 3Ά-3Ό) one to another, and wherein a fixing device (37) is provided for fixing the cover elements (3A, 3B; 3Ά-3Ό) one to another.

25. Apparatus according to any one of claims 21 to 24, wherein each cover element (3A, 3B; 3Ά-3Ό) is preferably provided with a dividing element (4, 5, 6; 4’, 41’, 5’, 6’).

26. Apparatus according to any one of claims 1 to 25 and further comprising a locking device (7, 8) for holding the separating membrane (20; 20’) in the desired position on the dividing device (4, 5, 6; 4’, 41’, 5’, 6’).

27. Apparatus according to claim 26 and further comprising a guide element (9) defined on at least one dividing element (5, 6) of the dividing device (4) and arranged for guiding the insertion of the locking device (7) thereon.

28. Apparatus according to any one of claims 1-27 and further comprising a limiting device (60) arranged to be inserted in the culture chamber (10; 10’) and configured for defining an active culture chamber (70) in the culture chamber (10; 10’) in which the cell culture is created.

29. Apparatus according to claim 28, wherein the limiting device (60) is provided with connection element for being connected to the separating device (4) so that the latter defines at least two active culture regions (70A, 70B) in the active culture chamber (70), for holding a separating membrane (20; 20’) so that the separating membrane (20; 20’) is interposed between the at least two different active culture regions (70A, 70B).

30. Apparatus according to claim 28 or 29, wherein the limiting device preferably comprises at least two limiting elements (61, 62) arranged to be positioned each one in one culture region (10A, 10B; 10Ά, 10’B, 10’C, 10’D’) and defining an active culture region (70A, 70B) in each one of the least one culture region (10A, 10B; 10Ά, 10’B, 10’C, 10’D’), wherein the limiting elements (61, 62) are preferably coupled to the dividing device (4, 5, 6; 4’, 41’, 5’, 6’) so as to define the at least two active culture regions (70A, 70B) in the corresponding at least two culture regions (10A, 10B; 10Ά, 10’B, 10’C, 10’D’).

31. Apparatus according to any one of claims 28 to 30, wherein the limiting device (60) is made of PDMS.

32. Apparatus according to any one of claims 1 to 31, wherein the dividing device (4, 5, 6; 4’, 41’, 5’, 6’) is so shaped to define two or more different culture regions (10A, 10B; 10’ A, 10’B, 10’C, 10’D’) in the culture chamber (10; 10’) .

33. Biocompatible system (500) for creating in vitro 3D cell cultures comprising: an apparatus (100; 100’) according to any one of claims 1-29, a supporting substrate (50) arranged for supporting the apparatus (100; 100’) and a seal for sealing the apparatus (100; 100’) to the supporting substrate (50) in order to define with the supporting substrate (50) a sealed culture chamber (10; 10’).

34. Biocompatible system (500) according to claim 33 and wherein the seal is applied at a support structure (1; 1’) of the apparatus (100; 100’) so that the seal is interposed between the support structure (1; 1’) and the supporting substrate (50) for sealing the supporting structure (1; 1’) to the supporting substrate (50) so as to define sealed culture chamber (10; 10’).

35. Biocompatible system (500) according to claim 33 or 34, wherein the supporting substrate (50) comprises an active portion made of MEA, the supporting substrate (50) being preferably made of MEA.

36. Biocompatible system (500) according to any one of claims 33 to 35, and further comprising a sealing element arranged between the separating membrane (20; 20’) and the supporting substrate (50) configured to allow the passage of fluids and/or of cellular connections (22) therethrough and to avoid the passage of cellular bodies (23) through the separating membrane (20; 20’) and between the at least two culture regions (10A, 10B; 10Ά, 10’B, 10’C, 10Ό’).

37. Biocompatible system (500) according to claim 36. wherein the sealing element is a sealing strip arranged between the separating membrane (20; 20’) and the supporting substrate (50).

38. Biocompatible system (500) according to any one of claims 33 to 37, and further comprising a further sealing element arranged between the dividing device (4) and the supporting substrate (50) configured to seal the at least two different culture regions (10A, 10B; 10Ά, 10’B, 10’C, 10’D’), the further sealing element being preferably a sealing layer arranged between the dividing element (4, 5, 6; 4’, 41’, 5’, 6’) and the supporting substrate (50).

39. Biocompatible system (500) according to claim any one of claims 33 to 38, wherein supporting substrate (50) comprises a coating provided on at least a portion of a face (50A) of the supporting substrate (50) facing in use the culture chamber (10;

10’) and arranged for facilitating the growth of the cells of the cell culture, the coating being preferably made of Poly-L-ornithine.

40. Biocompatible system (500) according to claim any one of claims 33 to 39 and further comprising a scaffold arranged in at least one of the culture region for improving the growth of the cell culture.