Assembly and growth of cell objects on a contact structure using axial and lateral acoustic radiation forces

Abstract

The present invention relates to an apparatus and a method for assembling objects (11, 12) by generating an axial acoustic radiation force to position the objects (11, 12) on pressure nodes (N1 to N4) and / or pressure antinodes, and further generating a lateral acoustic radiation force to move the objects (11, 12) positioned in this way onto a contact structure (4) of a porous membrane.

Description

[Technical field]

[0001] The present invention relates to the field of biotechnology, in particular to the assembly of cells or micrometer-sized particles, for example for the purpose of reconstructing or modeling living tissue.

[0002] The present invention is of particular interest, but is by no means limited to, in the fields of cell therapy, pharmacological modelling, food processing (e.g. meat, microalgae or plant culture) and also in space (especially cell culture in microgravity). [Background technology]

[0003] Research on organ-on-a-chip and organoid reconstruction and modeling is increasingly focused on experimental approaches aimed at structuring cell assemblies.

[0004] The most widely used techniques for this purpose include cell manipulation in microfluidic devices and tissue generation by additive manufacturing.

[0005] Another known technique is the structuring of cell sheets using acoustic levitation in hydrogels, as described in Non-Patent Document 1. This technique allows assembling cells in layers or sheets in hydrogels with the aim of establishing connections between the cells in different layers. However, this technique does not allow for a satisfactory control of the development of such connections.

[0006] More generally, assembly techniques known in the art are complex and expensive, can require long periods of time for cell assembly and culture, and, to the extent that they are performed in vitro (in an artificial, controlled environment such as a glass vessel), can lead to the death of large numbers of cells. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] Bouyer et al. “A bio-Acoustic Levitational (BAL) Assembly Method for Engineering of Multilayered, 3D Brain-Like Constructs, Using Human Embryonic Stem Cell Derived Neuro-Progenitors”, Adv. Mater. 2016, 28, 161-167. [Summary of the Invention]

[0008] The present invention aims to overcome the aforementioned drawbacks by providing an object assembly device including the following: - A cavity configured to receive a fluid and an object, - A generating system configured to generate a standing sound wave in the cavity along the axial direction and generate an axial acoustic radiation force (axial acoustic radiation force) suitable for placing the object at pressure nodes (pressure nodes (noeuds…de pression)) and / or antinodes (antinodes (anti-noeuds)) formed by the sound wave.

[0009] According to the present invention, the device includes a contact structure forming one or more surfaces extending along the axial direction, and the generating system is configured to apply a lateral acoustic radiation force (lateral acoustic radiation force) capable of moving the object toward the surface of the contact structure.

[0010] By propagating a standing sound wave in the cavity, one or more pressure nodes (places where the pressure of the fluid becomes zero) and one or more wave antinodes or pressure antinodes (places where this pressure is maximum) can be formed in the cavity along the axial direction.

[0011] In a method known per se, based on the properties of the object with respect to the fluid in the cavity, in particular the density-compressibility or the acoustic contrast, the axial acoustic radiation force moves the object towards a pressure node if the acoustic contrast is positive and towards a pressure antinode if the acoustic contrast is negative.

[0012] Thus, by means of the axial acoustic radiation force, one or more aggregates of objects can be successively formed axially in the cavity in a very short time of just a few seconds, in particular using a particularly simple and inexpensive device.

[0013] Preferably, the lateral acoustic radiation force generated after arranging the objects axially in this way brings each aggregate thus formed into contact with the contact structure.

[0014] Thus, the present invention can generate one or more assemblies of objects and hold these assemblies against the contact structure by acoustic levitation.

[0015] By maintaining such an assembly in the state of acoustic levitation for the required time (for example, several hours or days), when the object is a living being, especially when the object is a biological cell, the interaction between the objects can be promoted.

[0016] Thus, according to the present invention, for each assembly, by controlling the development of the binding or interaction between the cells of this assembly and / or between these cells and other objects or elements that can be arranged on or inside the contact structure, cell culture by acoustic levitation can be carried out. (See below)

[0017] As used herein, an "object" refers to a living or inert element, preferably of a size smaller than the wavelength of the standing sound wave generated in the cavity.

[0018] As a non-limiting example, usually when the frequency of the standing wave is a value in the MHz range, the object may be on the order of micrometers, for example, between 1 μm and 100 μm.

[0019] As another example, particularly when the generation frequency is in the kHz range, the object may be on the order of millimeters, for example, between 1 mm and 100 mm.

[0020] However, the present invention is also applicable to objects of other sizes. For example, part or all of the object may be less than 1 μm in size by being formed, for example, by bacteria or viruses, and / or may be on the order of hundreds of μm in size. Furthermore, part or all of the object may be a multi-cellular element or an artificially formed object, or an object taken from an organ.

[0021] The fluid in which the object is suspended is preferably a liquid and may contain water, form a culture medium, or more generally, form an aqueous medium containing, for example, a prepolymer of a hydrogel or colloidal particles, depending on the intended use.

[0022] The present invention also provides a particularly detailed solution regarding the spatial positioning of the object and can control the development of cell-cell interactions as needed.

[0023] Thus, the device of the present invention can be used for various applications and can form acoustic fluid chips having various structural characteristics, particularly regarding the contact structure.

[0024] In one embodiment, the contact structure includes one or more membranes or walls.

[0025] As used herein, a membrane (also referred to as a wall) generally refers to a structure that includes two surfaces that are relatively large compared to the thickness of this structure, i.e., the distance separating these two surfaces.

[0026] In one embodiment, the cavity includes a plurality of chambers separated by one or more of the membranes.

[0027] As a non - limiting example, the cavity may include two chambers, and the contact structure may include a single membrane arranged such that the first surface of the membrane separates one of these chambers and the second surface of the membrane separates the other chamber.

[0028] In one embodiment, each chamber includes a respective portion of the object.

[0029] Thus, in the foregoing example of partitioning the cavity into two chambers, the objects can be divided into two sets, with the objects of the first set arranged in one chamber and the objects of the second set arranged in the other chamber.

[0030] In this non - limiting example, the lateral acoustic radiation force can be configured to move the objects of the first set towards the membrane, gather these objects against the first surface of the membrane, and move the objects of the second set towards the membrane, gather these objects against the second surface of the membrane.

[0031] Objects of the first and second sets arranged at the same axial position can thus be gathered on both sides of the membrane, enabling, for example, the development of interactions through the membrane, especially when the membrane is porous.

[0032] Thus, in one embodiment, one or more of the membranes are porous.

[0033] In one embodiment, one or more of the surfaces formed by the contact structure are surfaces each extending about a respective direction.

[0034] Preferably, this direction is parallel or oblique to the axial direction.

[0035] For example, one or more of the surfaces formed by the contact structure may each extend about a respective direction so as to form a rotating surface centered about this direction, and may, for example, exhibit a cylindrical shape.

[0036] Such a rotating surface may have a cross-section that is relatively small compared to the wavelength of the standing sound wave generated within the cavity and / or the axial dimension of this rotating surface, thereby enabling one or more assemblies of objects, for example, in the form of a spherical or oval assembly, around such a surface.

[0037] In one embodiment, one or more of the surfaces formed by the contact structure can each form a hollow structure, for example, enabling the injection and / or removal of biological or chemical objects, elements, or samples, or encapsulating an object such as a biological cell within the contact structure.

[0038] Thus, in one embodiment, the device includes elements such as biological cells, and is connected to the contact structure such that an interaction between these elements and one or more of the objects is enabled when these objects are moved towards the surface of the contact structure.

[0039] Needless to say, these principles can be generalized such that, regardless of whether the contact structure takes the form of one or more membranes and / or hollow structures and / or one or more three-dimensional structures arranged about one or more directions and / or of any shape, one or more of the surfaces of the contact structure contain or carry elements that are cellularized or, more generally, contain biological, physicochemical, and / or physical information, for example, using molecules that promote or inhibit cell growth, nanoparticles, or micrometer- or nanometer-texturing elements.

[0040] In one embodiment, the contact structure includes or forms one or more electrodes and / or is conductive.

[0041] In one embodiment, the contact structure includes a gas-permeable material such as, for example, polydimethylsiloxane, and can diffuse oxygen, for example, into the core of the object assembly.

[0042] In one embodiment, the contact structure includes one or more wires that form one or more of the surfaces.

[0043] In one embodiment, the generating system includes one or more piezoelectric and / or ultrasonic transducers that can include a plurality of matrix-arrayed elements and / or one or more acoustic holographic lenses.

[0044] In one embodiment, the object includes objects having a positive acoustic contrast with respect to the fluid, whereby the axial acoustic radiation force moves these objects towards the pressure nodes, and / or the object includes objects having a negative acoustic contrast with respect to the fluid, whereby the axial acoustic radiation force moves these objects towards the pressure antinodes.

[0045] The present invention also relates to a method of assembling an object using the apparatus defined previously herein.

[0046] This method includes generating an axial acoustic radiation force to position the object at a pressure node and / or a pressure antinode, and generating a lateral acoustic radiation force to move the object towards the surface of the contact structure.

[0047] The lateral acoustic radiation force is preferably generated, for example, by a generating system having a matrix of piezoelectric elements, after positioning the object at a pressure node and / or a pressure antinode.

[0048] Alternatively, the axial and lateral acoustic radiation forces can be generated simultaneously, for example, by a generating system having a single transducer or an acoustic holographic lens.

[0049] This method may perform any number of steps that can obtain various combinations of the functional features described hereinbefore, particularly based on the structural features of the device, particularly the contact structure.

[0050] In at least some embodiments, the present invention does not cover, but is not limited to, applications in which the object contains human embryonic stem cells involving the destruction of a human embryo, or applications in which the present invention is implemented to construct or develop a human body.

[0051] Further advantages and features of the present invention will become apparent from the following detailed non-limiting description.

Brief Description of the Drawings

[0052] The following detailed description refers to the accompanying drawings:

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0053] Figure 1 schematically shows an example of a device according to a first embodiment of the present invention.

[0054] This device includes a container that forms a cavity 1 suitable for containing fluids and / or various substances, particularly substances in liquid form.

[0055] Typically, the cavity 1 extends along an axial direction A1 that corresponds to the vertical direction in this example. Along the axial direction A1, the cavity 1 has a dimension B1 that defines the height of the cavity 1.

[0056] In this example, the cavity 1 generally has a cylindrical shape, and the direction A1 forms the axis of symmetry of the cavity 1. In a variant not shown, the cavity 1 can have other shapes, for example, a rectangular cross-section.

[0057] The device of the present invention also includes an acoustic wave generation system, that is, a transducer 2 including matrix piezoelectric elements 2A and 2B and an acoustic reflector 3.

[0058] Referring to Figure 1, the transducer 2 is disposed at the first end of the cavity 1 along the direction A1, in this case vertically above the cavity 1. The reflector 3 demarcates the second end of the cavity 1 along the direction A1, in this case vertically below the cavity 1.

[0059] The piezoelectric elements 2A and 2B are arranged transversely, that is, across the width direction of the cavity 1, and each of these elements is arranged at a respective position in the radial direction with respect to the direction A1.

[0060] This system is configured to generate a standing wave in the cavity 1 and propagate the wave in the fluid contained therein along the axial propagation direction corresponding to the direction A1.

[0061] The standing wave can be generated by one or more piezoelectric elements of the transducer 2 at the same frequency as the resonance frequency of the cavity 1, in which case the cavity 1 forms a resonator. Alternatively, the standing wave can have a frequency different from the resonance frequency of the cavity 1.

[0062] In either case, this system is configured to be able to generate a wave having a wavelength λ that is at most twice the height B1 of the cavity 1, in particular, to form at least one pressure node and at least one pressure antinode along the direction A1.

[0063] In this example, the transducer 2 is a broadband transducer equipped with an ultrasonic source. Such a transducer 2 can be used to change the position of the nodes of the standing wave along the direction A1 and / or the distance between these nodes by adjusting the frequency of the wave.

[0064] In the embodiment of FIG. 1, the device comprises a wall 4 (also known as a "membrane") that extends into the cavity 1 and separates the cavity 1 into two chambers 5 and 6.

[0065] The membrane 4 comprises a first surface 7 that delimits the chamber 5 and a second surface 8 that delimits the chamber 6.

[0066] The membrane 4 and its surfaces 7 and 8 extend along the direction A1 and are parallel to this direction in this case.

[0067] In this example, the membrane 4 is made of nitrocellulose and has pores 9 that penetrate the membrane 4 and form openings on the surfaces 7 and 8.

[0068] For example, the membrane 4 may have a thickness of 150 μm defined as the distance between the surfaces 7 and 8 and pores with a diameter of 3 μm. Without limitation, the size of such pores can range from the nanometer scale to the micrometer scale.

[0069] In this example, the chambers 5 and 6 are filled with a fluid containing objects 11 and 12 sized from 1 μm to 100 μm respectively.

[0070] In this non - limiting example, the object 11 is a first type of biological cell received in the chamber 5, while the object 12 is a second type of biological cell received in the chamber 6. This fluid forms the medium for the cell objects 11 and 12.

[0071] Without limitation, the objects 11 and 12 may be neurons or glial cells, tumor cells, endothelial cells, epithelial cells, bone cells, or immune cells.

[0072] In this particular example, each of the objects 11 and 12 has a density ρ f greater than the density ρ o of the fluid. Further, the objects 11 and 12 are selected such that the speed of sound propagation c o in these objects 11 and 12 is greater than the speed of sound propagation c f in the fluid.

[0073] In this example, the apparatus of FIG. 1 is implemented such that the objects 11 and 12 can be constructed as described below.

[0074] In an initial state (not shown), the objects 11 and 12 are suspended in the fluid within the chambers 5 and 6 respectively.

[0075] In this example, the transducer 2 is implemented to generate a standing sound wave having a wavelength that forms four pressure nodes N1 to N4 along the direction A1 within the cavity 1. In this case, the wave is generated by the piezoelectric element 2A identified by the rectangle with a cross in FIG. 1, and the piezoelectric element 2B identified by the rectangle without a cross in FIG. 1 is deactivated.

[0076] This standing wave generates an axial acoustic radiation force acting on the objects 11 and 12.

[0077] This axial acoustic radiation force FRA A can be described, in particular, by the following model by K. Yosioka and Y. Kawasima, which is well-known per se:

[0078]

Number

[0079]

Number

[0080] The acoustic contrast coefficient or density - compressibility F y can be defined as follows:

[0081]

Number

[0082] Considering the densities of objects 11 and 12 and the propagation speed of sound waves with respect to the fluid, objects 11 and 12 have a positive density - compressibility, i.e., an acoustic contrast coefficient.

[0083] Considering the above - mentioned characteristics of the fluid and objects 11 and 12 respectively, the axial acoustic radiation force moves objects 11 and 12 from the initial state in which objects 11 and 12 are relatively uniformly distributed throughout cavity 1 towards the nodes of the standing sound wave, leading to the arrangement shown in FIG. 1.

[0084] Thus, as shown in FIG. 1, the axial acoustic radiation force results in the positioning of objects 11 and 12 in the form of a group, also called an "aggregate", located radially at the position of the activated piezoelectric element 2A.

[0085] Therefore, the group 21 of objects 11 is formed axially at pressure node N1 and radially at piezoelectric element 2A facing chamber 5. The other three groups 22, 23, and 24 of objects 11 are formed axially at pressure nodes N2, N3, and N4 respectively and radially at the same level as group 21.

[0086] Symmetrically, the group 25 of objects 12 is formed axially at pressure node N1 and radially at piezoelectric element 2A facing chamber 6. The other three groups 26, 27, and 28 of objects 12 are formed axially at pressure nodes N2, N3, and N4 respectively and radially at the same level as group 25.

[0087] The activated piezoelectric element 2A can maintain objects 11 and 12 in an acoustic levitation state for the time required to achieve sufficient self - organization of the aggregates 21 - 28, which substantially form an oval three - dimensional structure in this example.

[0088] Next, the transducer 2 is controlled to generate a lateral acoustic radiation force to move the objects 11 and 12 towards the diaphragm 4, and in particular to press the assemblies 21 - 24 located in the chamber 5 against the surface 7 of the diaphragm 4 and the assemblies 25 - 28 located in the chamber 6 against the surface 8 of the diaphragm 4.

[0089] In this example, such a lateral acoustic radiation force is achieved by changing the activation states of the piezoelectric elements 2A and 2B, that is, by gradually activating the piezoelectric elements in the radial direction of the direction A1 and deactivating the previously activated piezoelectric elements as new piezoelectric elements are activated.

[0090] In this way, the transducer 2 can spatially control the acoustic field in the cavity 1 and apply a lateral acoustic radiation force that can translate the assemblies 21 - 28 towards the diaphragm 4 until the arrangement shown in FIG. 2 is reached.

[0091] In a manner known per se, the lateral acoustic radiation force FRA T can be expressed as follows as a function of the gradient of the acoustic energy density:

[0092]

Number

[0093]

Number

[0094] In the arrangement of FIG. 2, the piezoelectric elements 2A located radially with respect to the diaphragm 4 can remain activated in order to keep the assemblies 21 - 28 in contact with the diaphragm 4 by acoustic levitation.

[0095] Thus, according to the present invention, in this example, aggregates 21 to 24 of objects 11 of the first type and aggregates 25 to 28 of objects 12 of the second type can be assembled into an object structure such that different types of objects located on the same acoustic levitation plane can establish contact via a porous membrane 4 in this example without directly contacting each other.

[0096] Such a membrane 4 can control the interaction between objects 11 and 12, particularly when objects 11 and 12 are primary neurons, by providing a passage for axonal type connections through pores 9.

[0097] Numerous modifications can be made to the apparatus and its implementation described herein. For example, the height B1 of the cavity 1 and / or the frequency of the standing acoustic wave can be changed to increase the number of pressure nodes, for example, to assemble several dozen aggregates simultaneously.

[0098] Also, for example, the size and shape of objects 11 and 12 can be changed to determine the number of objects per aggregate or assembly and the size of the resulting aggregate or assembly. The concentration of objects in cavity 1, the volume of cavity 1, or the wave frequency can also be changed. The selection of the amplitude and frequency of the acoustic wave that sets the magnitude of the acoustic radiation force can also be controlled to change the lateral and / or axial dimensions of the assembly. The amplitude of the acoustic pressure applied to the object assembly can also be controlled, for example, to enforce a specific spatial organization or to stimulate the objects to enforce a specific spatial organization and / or function.

[0099] As another example, the membrane 4 can be a glass wall or, more generally, a non-porous structure, particularly allowing the use of different fluids in chambers 5 and 6 of cavity 1, respectively. Such a wall can of course be functionalized and / or cellularized and / or gas permeable.

[0100] Other non-limiting embodiments of the present invention will be described below, but it will be understood that the foregoing description is also applicable by analogy to these various embodiments and their variations. Therefore, in the following description, these embodiments will be described mainly from the viewpoint of differences from the embodiments shown in FIGS. 1 and 2.

[0101] In the embodiments shown in FIGS. 3 and 4, the contact structure 4 does not include one membrane, but includes two porous membranes 4A and 4B that separate the cavity 1 into four chambers 5A, 5B, 6A, and 6B. Each of the chambers 5A, 5B, 6A, and 6B contains objects 31, 32, 33, and 34 having different properties.

[0102] According to such an apparatus, a complex assembly can be formed, in which case the type of object is doubled with respect to the apparatus shown in FIG. 1.

[0103] More generally, therefore, the contact structure 4 can be configured to partition the acoustic levitation cavity into a plurality of independent chambers using different culture media as needed. In particular, this makes it possible to maintain one type of cell in an acoustically levitated state for each chamber and culture it three-dimensionally within a single acoustic fluid chip.

[0104] By controlling the frequency of the radiated acoustic wave and / or the shape of the reflector, and as a result, controlling the spatial pattern of the acoustic field generated in the cavity, cell objects floating with respect to a contact structure such as a membrane can be brought into contact during the start or during the culture.

[0105] In these various examples, various symmetric or asymmetric shapes of the reflector 3 can be implemented to promote a predetermined spatial organization of the assembly of acoustically levitated objects, such as a sheet-like, spherical or oval structure, a ring-like, or an independent lobe-like organization.

[0106] The membrane of the contact structure may be of various physicochemical types, such as formed of, for example, hydrogel, elastomer, or inorganic material, and / or may contain micrometer or nanometer-sized structures.

[0107] By using a membrane with controlled porosity, on the one hand, the self-assembly of various aggregates, especially spheroids, can be controlled, thereby enabling the reconstruction of complex multicellular assemblies, and on the other hand, the nature of the interactions between various types of aggregates can be controlled. For example, the exchange of solutes, especially using membrane pores in the sub-micrometer size range, the elongation of cells, especially neurons with axons, using porosity between 1 μm and 5 μm, or the exchange of cells or objects, especially using porosity greater than 5 μm, can be controlled.

[0108] Furthermore, one or more chambers separated by one or more membranes, or more generally by a contact structure that can be configured in other ways, can be used only for the initial structuring step, i.e., object assembly, and these assemblies can then be cultured in a conventional manner, for example, in a liquid medium or in a hydrogel. Alternatively, the device of the present invention can be used for long-term culture by acoustic levitation.

[0109] In the embodiments shown in FIGS. 1 and 2, the lateral acoustic radiation force is generated by selective activation of the piezoelectric elements of the transducer 2. Needless to say, this force can also be generated using another type of acoustic field control member, for example, using an acoustic holographic lens. As is well known, an acoustic holographic lens can be encoded at multiple frequencies. Thus, the first frequency can be used to organize the objects into aggregates as shown in FIG. 1, and the second frequency can be used to hold these aggregates back against the contact structure 4 and form an assembly as shown in FIG. 2. More generally, a wave generation system that generates axial and lateral acoustic radiation forces may include various types of and / or one or more transducers or combinations of transducers located axially and / or laterally.

[0110] Another type of contact structure is shown in FIGS. 5 and 6.

[0111] Referring to FIG. 5, the device comprises a contact structure including an array of contact elements 40 each having an elongated shape along the axial direction A1 of the cavity 1.

[0112] In this non-limiting example, each contact element 40 has a cylindrical shape so as to form an outer surface 41 extending around a direction A2 parallel to the axial direction A1 of the cavity 1.

[0113] Similar to the embodiments shown in FIGS. 1 and 2, the acoustic wave generation system of the device shown in FIG. 5 also includes an ultrasonic transducer 2 with piezoelectric elements 2C arranged in a matrix and a reflector 3 extending in a plane lateral to the cavity 1, and can move an object 42 present in the cavity 1.

[0114] From an initial state (not shown) where the object 42 is suspended in a fluid, the axial acoustic radiation force due to the standing wave generated by the transducer 2 arranges the object 42 in the form of an aggregate as shown in FIG. 5.

[0115] In this particular example, the assembly of objects 42 is formed on three pressure nodes formed by standing waves, the objects 42 exhibit a positive acoustic contrast with respect to the fluid, face laterally the activated piezoelectric element 2C and are formed in this configuration at a position remote from the contact element 40.

[0116] Next, as in the embodiments shown in FIGS. 1 and 2, the activation of the piezoelectric element 2C is changed to generate a lateral acoustic radiation force that causes the movement of the assembly around the contact element 40, as shown in FIG. 6. In this example, a spherical assembly that can be cultured in this way is formed.

[0117] The contact elements 40 may be of various physicochemical and geometrical types. For example, they may be solid or hollow, permeable or non-permeable, electroactive or non-electroactive and enable the perfusion, stimulation, monitoring and / or sampling of the assembly in a controlled manner.

[0118] Thus, in an alternative embodiment, the contact element 40 can form an electrode for the purpose of measuring or imposing electrical activity. Electroactive and / or conductive contact elements 40 can be used, in particular, for modeling angiogenesis phenomena, together with electrical stimulation and the recording of the electrical activity of the assembly of objects 42.

[0119] In an alternative embodiment, the contact element 40 can be made hollow and / or porous, for example, to enable the injection and trapping of solutes such as biological and physical compounds or agents, cells, or viruses inside the contact element 40 and the perfusion of the assembly of objects 42. The nature of the diffusion / movement of such solutes can be controlled through the porosity of the contact element 40.

[0120] Such alternatives can be implemented in combination with other types of contact structures, such as one or more membranes 4, previously described herein with reference to FIGS. 1-4 above.

[0121] More generally, the contact structure of the device of the present invention can be functionalized to modify the interaction between cell objects assembled on the contact structure.

[0122] Also, the functionalization of the contact structure may include grafting an object onto one or more surfaces of the contact structure and / or inside the contact structure, for example, inside the contact element 40 shown in FIGS. 5 and 6. The grafted object may be, for example, a particle that imparts new properties to the contact structure in terms of electrical, magnetic, or acoustic conductivity, a bioactive substance that affects the development of cell objects, or a cell, such as an endothelial cell or an astrocyte, or other organisms.

[0123] In an alternative embodiment, the contact element 40 of the device shown in FIGS. 5 and 6 can be formed, for example, of a cured hydrogel by confocal photopolymerization. These contact elements 40 can include cell objects or functionalized objects captured in the hydrogel forming these contact elements 40, such as those previously described herein. Needless to say, such contact elements can have a complex three-dimensional shape with any degree of difference, for example, forming a lattice structure or the like.

[0124] The present invention enables a wide range of applications including the reconstruction of complex tissue elements, for example, the modeling of serial multi-organ interactions such as the interaction between different regions of the brain, and the serial or parallel arrangement of organ models. As other examples of applications, the present invention enables the three-dimensional reconstruction of neuroanatomical pathways or the three-dimensional modeling of blood-brain or placental tissue barriers. In the context of neuroscience, the anisotropy of membrane porosity (e.g., conical pores) can be used to control the direction of axonal and / or neural growth from one organoid to another. As another example, by cellularizing a porous or non-porous membrane, particularly by pre-seeding the membrane with the cells of interest, complex biological interfaces can be modeled.

Claims

1. An apparatus for assembling objects (11, 12, 31 - 34, 42), comprising: - a cavity (1) configured to receive a fluid and the objects (11, 12, 31 - 34, 42); - a generating system (2) configured to generate a standing acoustic wave along an axial direction (A1) within the cavity (1) and generate an axial acoustic radiation force suitable for positioning the objects (11, 12, 31 - 34, 42) on pressure nodes (N1 - N4) and / or pressure antinodes formed by the acoustic wave; The apparatus further comprises a contact structure (4, 40) forming one or more surfaces (7, 8, 41) extending along the axial direction (A1), and the generating system (2) is configured to apply a lateral acoustic radiation force capable of moving the objects (11, 12, 31 - 34, 42) towards the surfaces (7, 8, 41) of the contact structure (4, 40).

2. The apparatus according to claim 1, wherein the contact structure includes one or more membranes (4, 4A, 4B).

3. The cavity (1) includes a plurality of chambers (5, 6, 5A, 5B, 6A, 6B) separated by one or more of the membranes (4, 4A, 4B), and each of the chambers (5, 6, 5A, 5B, 6A, 6B) preferably includes a respective part of the objects (11, 12, 31 - 34). The apparatus according to claim 2.

4. The apparatus according to claim 2 or claim 3, wherein one or more of the membranes (4, 4A, 4B) are porous.

5. One or more of the surfaces (41) formed by the contact structure (40) are surfaces extending around respective directions (A2), and this direction (A2) is preferably parallel or oblique to the axial direction (A1). The apparatus according to any one of claims 1 - 4.

6. The apparatus according to any one of claims 1 - 5, wherein the contact structure (4, 40) includes or forms one or more electrodes.

7. The apparatus according to any one of claims 1 - 6, including elements such as biological cells connected to the contact structure (4, 40), and the interaction between these elements and one or more of the objects (11, 12, 31 - 34, 42) becomes possible when the objects move towards the surfaces (7, 8, 41) of the contact structure (4, 40).

8. The device according to any one of claims 1 to 7, wherein the generating system (2) comprises one or more piezoelectric and / or ultrasonic transducers that can include elements (2A, 2B, 2C) arranged in a plurality of matrices and / or one or more acoustic holographic lenses.

9. The device according to any one of claims 1 to 8, wherein the objects (11, 12, 31 to 34, 42) include objects having a positive acoustic contrast with respect to the fluid, whereby the axial acoustic radiation force moves these objects towards the pressure nodes (N1 to N4), and / or include objects having a negative acoustic contrast with respect to the fluid, whereby the axial acoustic radiation force moves these objects towards the pressure antinodes.

10. A method of assembling objects (11, 12, 31 to 34, 42) using the device according to any one of claims 1 to 9, the method comprising generating the axial acoustic radiation force to position the objects (11, 12, 31 to 34, 42) on the pressure nodes (N1 to N4) and / or the pressure antinodes, and further generating the transverse acoustic radiation force to move the objects (11, 12, 31 to 34, 42) towards the surfaces (7, 8, 41) of the contact structure (4, 40).

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