PLATELET RELEASE SYSTEM AND PLATELET RELEASE METHOD

Description

Technical field of the invention

[0001] The invention relates to a system for the release of platelets from a fluid comprising in particular megakaryocyte progenitors, megakaryocyte cells having cytoplasmic extensions. The invention also relates to an assembly provided with a plurality of systems such as this. Finally, the invention relates to a method for the continuous release of platelets by means of such a system. The invention is more particularly adapted to the in vitro production of blood platelets on an industrial scale. Technical background

[0002] In vitro production of blood platelets meets growing needs in various medical applications. Currently, there are essentially two categories of systems designed for this specific use: microfluidic systems and "reservoir" systems. These categories of systems designed to release platelets are derived from in situ observations that demonstrate the need for flow.

[0003] An example of a reservoir system is described in document WO201909364 A1. The system is provided with means for agitating the fluid to be treated. It comprises a reservoir for the fluid including in particular the megakaryocytic cells and at least one means for agitating the fluid, the agitation being the cause of the release of the platelets. This agitation is generated inside the reservoir itself, for example, by means of a vertically reciprocating blade. The main disadvantage of such a system is that it is not capable of operating under conditions guaranteeing the quality of the platelets thus obtained since it is not isolated from the external environment and the sources of contamination present in this environment, which makes it unsuitable for medical use. WO2009131645 discloses an apparatus for segregating cells based on their ability to flow in a stepped passage.

[0004] Microfluidic systems, as their name suggests, are generally systems of micrometric dimensions (a few tens of microns to a few hundred microns at most) comprising a network of reservoirs and channels interconnected in a particular arrangement to fulfill different functions. They typically include a site dedicated to the culture of megakaryocytic cells or megakaryocytes, and possibly to the release of platelets, the site being connected to a network of channels configured to extract / recover platelets. These systems, mostly biomimetic, seek to reproduce the physiological environment in order to increase platelet production.

[0005] Due to their small size, these microfluidic systems have two intrinsic limitations. The first is the low platelet throughput that can be achieved by such systems, typically a few hundred microliters per hour (µL / h). For example, a system with a flow rate of 200 µL / h would require 50,000 hours, or 5.7 years, to process 10 L of fluid. It is then necessary to connect several systems in parallel to obtain a comparable total throughput. However, in the example above, the number of systems required would be very high, i.e. 50,000, and the complexity of the system would be even greater. At best, such systems are therefore only suitable for limited volumes of fluid samples.

[0006] Furthermore, microfluidic devices described in the literature all implement a mechanism / process that "fixes" megakaryocytes and then extracts platelets from them. This fixation phase is often based on the use of a drug or a chemical coating compound, which is a disadvantage.

[0007] More recently, a new method for releasing platelets from megakaryocytic cells using pipetting has been developed. Such a method is described in the document Strassel et al. "Aryl hydrocarbon receptor-dependent enrichment of a high potential to produce propalets", Blood, May 5, 2016, vol. 127, no. 18. In such a method, the platelet release process results directly from pipetting. The pipetting in question is similar to conventional pipetting since it consists of taking a sample of a medium containing megakaryocytic cells using a pipette except that the pipetting action is repeated as many times as necessary to create the agitation necessary for the release of platelets. At the end of this process, platelets were detected in the treated fluid, thus validating the ability of pipetting for the release of platelets, which is also very simple to implement.However, this process is not suitable for large-scale operation since pipetting is by nature manual and is therefore only intended to treat limited volumes of fluid. Summary of the invention

[0008] The invention makes it possible to overcome the aforementioned drawbacks and to this end proposes a system for releasing platelets from a fluid comprising in particular megakaryocytic cells having cytoplasmic extensions, said system comprising: a device comprising: ∘ a platelet release reservoir comprising a first opening and a second opening, ∘ a first fluid connection element fixed at said first opening and adapted to inject said fluid into said reservoir, said first connection element comprising an orifice for injecting the fluid into the platelet release reservoir and a portion narrowed towards said orifice, a sudden widening of section existing between the injection orifice and the reservoir, ∘ a second fluid connection element fixed at said second opening, said second connection element comprising a fluid discharge orifice, a fluid pumping device in fluid communication with the reservoir via the second fluid connection element or the first fluid connection element, an electrical power supply module for the pumping device,a programming system configured to control the power supply module of the pumping device, in order to implement one or more platelet release sequences carried out so as to generate a continuous flow of fluid between said injection port and said discharge port as well as vortex disturbances within the reservoir causing the fragmentation of the cytoplasmic extensions of the megakaryocytic cells.

[0009] The system according to the invention is thus configured to reproduce the pipetting process carried out manually using a pipette, which allows continuous and automatic release of the platelets.

[0010] However, this is done on a large scale because the geometry of the system according to the invention makes it possible to treat large volumes of fluid with a high flow rate (of the order of several liters per hour), which makes it particularly suitable for use on an industrial scale.

[0011] Furthermore, the system makes it possible to obtain a number of platelets released from the megakaryocyte cells at least equivalent to that obtained from manual pipetting, which makes it a system with a particularly high platelet release efficiency. This is achieved mainly due to the synergy between the shape of the system elements, i.e. in particular the taper of the first fluid connection element and the large dimensions of the reservoir, and the flow velocity generated by the pumping device. This makes it possible to generate vortex disturbances substantially the size of the megakaryocytes within the reservoir.

[0012] According to different characteristics of the invention which may be taken together or separately: the narrowed portion is conical; the first connecting element comprises a longitudinal axis and the second connecting element comprises a longitudinal axis, said longitudinal axes being either intersecting or parallel and then separated by a non-zero distance, d,; the injection orifice has an opening diameter of less than 1 mm; a ratio of the opening diameter of the injection orifice to a section width of the reservoir is between 0.02 and 0.1; the ratio of the opening diameter of the injection orifice to the section width of the reservoir is 0.05; the discharge orifice has an opening diameter of less than 1 mm, a ratio of the opening diameter of the discharge orifice to a section width of the reservoir is between 0.02 and 0.1; the ratio of the opening diameter of the discharge orifice to the section width of the reservoir is 0.05; the reservoir has a spherical shape;the system comprises a source reservoir for storing the fluid, connected to the first fluid connection element for supplying the platelet release reservoir; the system comprises a fluid receiving reservoir connected to the second fluid connection element for collecting said fluid intended to be drawn from the platelet release reservoir; the pumping device is located in the receiving reservoir; said second connection element further comprises a flared portion from said fluid discharge port towards the pumping device;the system comprises another device, said other device comprises: ∘ a platelet release reservoir comprising a first opening and a second opening, ∘ a first fluid connection element fixed at said first opening and adapted to inject said fluid inside said reservoir, said first connection element comprising a fluid injection orifice and a first narrowed portion so as to be able to accelerate the fluid, said first narrowed portion opening onto said injection orifice, ∘ a second fluid connection element fixed at said second opening, said second connection element comprising a fluid discharge orifice, said other device being arranged parallel to the first device and connected to the pumping device via the second of said another device;the system comprises another device, the other device comprises: ∘ a platelet release reservoir comprising a first opening and a second opening, ∘ a first fluid connection element fixed at said first opening and adapted to inject said fluid into said reservoir, said first connection element comprising a fluid injection orifice and a first narrowed portion so as to be able to accelerate the fluid, said first narrowed portion opening onto said injection orifice, ∘ a second fluid connection element fixed at said second opening, said second connection element comprising a fluid discharge orifice, said other device being arranged in series with the first device, said second connection element of said other device being in fluid communication with said first fluid connection element of said first device. ;

[0013] The invention further relates to a method for releasing platelets from a fluid comprising in particular megakaryocytic cells comprising cytoplasmic extensions, said method comprising the following steps, implemented by means of a system as previously described: (100) providing a fluid comprising megakaryocytic cells suspended in said fluid, said megakaryocytic cells comprising cytoplasmic extensions, (200) electrically powering the pumping device, (300) controlling the programming system in order to initiate one or more platelet release sequences, the or each platelet release sequence being carried out so as to generate a continuous flow of the fluid between said injection port and said discharge port as well as vortex disturbances within the reservoir causing the fragmentation of the cytoplasmic extensions of the megakaryocytic cells.

[0014] Advantageously, during step (200), a relative vacuum of between -10 kPa and -50 kPa is generated in the device. Brief description of the figures

[0015] Other objects and characteristics of the invention will appear more clearly in the following description, made with reference to the appended figures, in which: [ Fig. 1a ] Fig. 1a is a schematic representation of a system according to a first embodiment of the invention, a reservoir for the fluid being illustrated in section according to a side view; [ Fig. 1b ] Fig. 1b is a schematic representation of an alternative embodiment of the system of the Figure 1a ; [ Fig. 1c ] There Figure 1c is a close-up view of a reservoir equipping the system illustrated in Figure 1b ; [ Fig. 2a ] There Figure 2a is a schematic representation of a system according to a second embodiment of the invention comprising a plurality of devices connected in series; [ Fig. 2b ] There Figure 2b represents an exploded view of a system according to the invention comprising five devices mounted in series; [ Fig. 2c ] There Figure 2crepresents a set as illustrated in Figures 2a and 2b , the assembly is here connected to a source tank and a fluid receiving tank; [ Fig. 2d ] There figure 2d is a schematic representation of an assembly according to a third embodiment of the invention, comprising a plurality of devices mounted in parallel; [ Fig. 3a ] There Figure 3a is a schematic representation of a method according to the invention; [ Fig. 3b ] There Figure 3b is a schematic representation of the process of the Figure 3a in which the sub-steps of carrying out the process are illustrated; [ Fig. 4a ] There Figure 4a illustrates a proplatelet megakaryocytic cell; [ Fig. 4b ] There Figure 4b illustrates platelets obtained after the platelet release method according to the invention; [ Fig. 5a ] There Figure 5ais a comparative figure illustrating the platelet release efficiency obtained using a pipette and using a system according to the invention as a function of the relative vacuum within said system; [ Fig. 5b ] There Figure 5b is an analysis of the functionality of platelets obtained at a pressure of -30 kPa for native platelets (hollow bars) and cultured platelets (solid bars). Detailed description of the invention

[0016] In reference to the Figures 1a to 1c , the invention relates to a system 1 for the release of platelets P from a fluid F comprising megakaryocytic cells Mk.

[0017] The fluid F in question is, for example, a culture medium containing a population of cells obtained from immortalized or non-immortalized stem cells at different stages of differentiation, including megakaryocyte progenitors, megakaryocytes. Megakaryocytes or megakaryocytic cells are large blood cells (up to 100 µm and 30 µm in culture) which, when they have reached maturity, have long extensions called cytoplasmic extensions or cytoplasmic extensions or proplatelets.

[0018] The mechanisms involved in the formation of blood platelets are still the subject of much research. Among them, the release of platelets occurs during a process of fragmentation of megakaryocytes Mk and / or cytoplasmic extensions, Ck, into platelets. This is a process in vivohighly coordinated process occurring naturally in the blood thanks to the force of blood flow. Mk megakaryocytes play an essential role since they are precursor cells. However, the process of platelet release in the body remains poorly described and the transendothelial passage and the precise role of blood flow in platelet formation still raise many questions. This process has been reproduced in vitro using microfluidic systems, which has made it possible to corroborate certain mechanisms in vivo by microfluidic experiments. This process can also be reproduced in vitro by means of a pipette manually or by means of devices such as those presented in the introductory part of this description, which also allows a better understanding of the mechanisms involved in the release of platelets (Strassel et al.2016). In vitro platelet production provides a better understanding of the mechanisms involved in platelet formation. However, platelet release yields are generally lower than those obtained in vivo. The device proposed by the invention makes it possible to mimic the process of platelet release by manual pipetting disclosed by Strassel et al., without reproducing the back and forth movement generated during pipetting which is replaced by a continuous movement using system 1. The invention thus aims to reproduce the process of fragmentation of megakaryocytes Mk and / or cytoplasmic extensions Ck on an industrial scale and therefore makes it possible to treat large volumes of fluid F (several liters per hour).

[0019] The system 1 according to the invention comprises a device 2, a pumping device 60 and a programming system 70 which we will describe in the following sections.

[0020] The device 2 comprises a platelet release reservoir 10, a first fluid connection element 20 and a second fluid connection element 30.

[0021] The wafer release reservoir 10 (hereinafter referred to as "reservoir 10") has millimeter to centimeter longitudinal dimensions, i.e. longitudinal dimensions between 1 mm and a few centimeters. For comparison, the smallest dimension of the reservoir 10 of the system 1 according to the invention is the largest dimension of a traditional microfluidic system. This therefore makes it a reservoir of larger dimensions and capacity than those of known microfluidic systems.

[0022] In the example embodiment illustrated in the Figure 1a, the reservoir 10 is spherical in shape. It comprises a spherical wall 12 delimiting a cavity 14 within which the fluid F can circulate. In addition to being a zone for the circulation of the fluid F, the cavity is a zone allowing a turbulent flow of the fluid F, that is to say allowing the formation of vortex disturbances of sizes at least equal to those of the megakaryocytes Mk. In other words, the cavity 14 by its dimensions, as previously described, on the one hand and by its internal volume on the other hand is configured so as to allow the formation of vortex disturbances within it. However, the reservoir 10 could be of any other shape, for example, parallelepiped, cylindrical, etc., the most important being that said reservoir 10 comprises a cavity 14 of sufficient dimensions to allow the formation of vortex disturbances.For example, for a fluid F comprising Mk megakaryocytes, the size of which, as we have seen, can reach 30 µm in culture, the cavity 14 therefore has significantly larger dimensions (millimetric to centimetric) since the fluid F comprises a plurality of Mk megakaryocyte cells, for example hundreds or even thousands.

[0023] The wall 12 comprises at least a first opening 16 and a second opening 18. The first opening 16 is dedicated to the fluid connection with the first connection element 20, while the second opening 18 is dedicated to the fluid connection with the second connection element 30. Preferably, they form the only openings of the wall 12 since the system 1 is closed.

[0024] The first fluid connection element 20 is a means for supplying the fluid F into the reservoir 10. In other words, it is an inlet for the fluid F into the reservoir 10. It is fixed at the first opening 16 of the reservoir 10. It comprises a connecting portion 26, a narrowed portion 24 and a fluid injection orifice 22 in this order in the direction of flow of the fluid. The narrowed portion 24 therefore opens onto the injection orifice 22. That being said, it will be noted that the connecting portion 26 is not essential as this will be better understood below. Thus, in the exemplary embodiment illustrated in Figure 1a, the first fluid connection element 20 is fixed at the level of the first opening 16 via the connecting portion 26, but it can be fixed to the reservoir 10 according to other configurations. Indeed, it can just as easily be fixed via the narrowed portion 24 as via the injection orifice 22. In this latter configuration, it will then be understood that the injection orifice 22, by being located at the level of the wall 12, can correspond to, i.e. coincide with, the first opening 16 of the reservoir.

[0025] As mentioned previously, the portion 24 is narrowed. The portion 24 is narrowed in that it narrows from the connecting portion 26 or, alternatively in the absence of a connecting portion 26, one end of the first connecting element 20 towards the fluid injection orifice 22. In other words, it narrows in the direction of flow relative to a longitudinal axis X1 of said first connecting element 20 passing through the center of said orifice 22. The narrowed shape of said portion 24 makes it possible to accelerate the fluid F by the venturi effect. Incidentally, the fluid F entering the reservoir 10 therefore has a greater speed compared to a fluid which would enter the system 1 through a portion 24 which does not have a flare.

[0026] Advantageously, the narrowing of the tapered portion 24 from the connecting portion 26 or, alternatively in the absence of a connecting portion 26, the end of the first connecting element 20 towards the fluid injection orifice 22 can be substantially constant. The constancy of the narrowing makes it possible to reduce friction and to further increase the acceleration of the fluid. In this respect, the tapered portion 24 can be conical. Advantageously, the use of a conical portion 24 facilitates the connection with tubular fluid connection means, i.e. cylindrical in shape, frequently sold commercially. For example, the portion 24 can have a pyramidal, tetrahedral, etc. shape. What is important above all is that the tapered portion 24 narrows from the connecting portion 26 of the first connecting element 20 towards the fluid injection orifice 22.That being said, once discharged into the reservoir 10, the fluid F slows down substantially due to the difference in section existing between the first fluid connection element 20, in particular the injection orifice 22, and the reservoir 10.

[0027] Indeed, the injection orifice 22 advantageously has a very small opening diameter compared to the diameter of the reservoir 10, in the case of a spherical species. However, this diameter is greater than or equal to the size of the particles leaving the reservoir 10, i.e. the platelets P and other products, Dk, resulting essentially from the fragmentation of the megakaryocytes. Preferably, the opening diameter is less than or equal to 1 mm, whereas as we have seen, the reservoir 10 has longitudinal dimensions of millimeters to centimeters, in any case much greater than those of the orifice 22. Let us specify at this stage that the shape of the injection orifice 22 is not limiting. What matters here is the size of said injection orifice 22.

[0028] Thus, a sudden widening of section exists between the injection orifice 22 and the reservoir 10. This sudden widening corresponds to a singularity and gives rise to a singular flow profile of the fluid F. As mentioned previously, the fluid F is accelerated at the outlet of the narrowed portion 24 through the injection orifice 22, then undergoes a pressure drop, i.e. a slowdown, during its passage from the injection orifice 22 to the reservoir, due to this singularity. The smaller the ratio, RE, of the diameter of the injection orifice 22 by the diameter or, more generally, the width in section of the reservoir 10 is in front of 1, the more the singularity will be accentuated, the greater the pressure drop and vice versa when this ratio increases. An example of system 1 according to the invention having been implemented comprises a reservoir 10 with a diameter equal to 16 mm and an injection orifice 22 with a diameter equal to 0.8 mm (RE is therefore equal to 0.05).If such a system 1 makes it possible to obtain improved platelet release efficiencies, ratios RE of the opening diameter of the orifice 22 by the section width of the reservoir between 0.02 and 0.1 can also be envisaged for releasing platelets from a fluid F, always for an injection orifice 22 with an opening diameter of less than 1 mm. Advantageously, RE is between 0.04 and 0.08 for an opening diameter of less than 1 mm. More advantageously, RE is between 0.04 and 0.06 for an opening diameter of less than 1 mm. That being said, even more advantageously RE is equal to 0.05. Indeed, in the latter case, the platelet release efficiency is better.

[0029] However, as will be explained later, although the fluid F is slowed down upon entering the reservoir 10 and maintains a laminar flow regime in the strict sense of the term - the Reynolds number varying between 0, at the center of a vortex whose size is close to that of the reservoir 10, and 1500, at the injection orifice 22, it is not stationary within said reservoir 10 due to the fluid displacement generated by the pumping device 60. The reservoir 10 is therefore only a place of passage for the fluid F, and is not a place of storage of said fluid F, that is to say a place in which the fluid is caused to stagnate when the system 1 is in operation.

[0030] In this regard, let us specify that in addition to the reservoir 10 for releasing the platelets, the system 1 may also comprise a source reservoir 40 for storing the fluid F connected to the first fluid connection element 20 to supply the reservoir. The fluid F may therefore be stored in the source reservoir 40 prior to its passage into the first element 20, but this is not obligatory. The reservoir 40 is therefore the most upstream element of the system 1 in the direction of flow.

[0031] In addition, the system 1 may also comprise a reservoir 50 for receiving the fluid F. The reservoir 50 for receiving the fluid F is connected to the second fluid connection element 30 to collect said fluid intended to be sucked from the reservoir. Unlike the source reservoir 40, the receiving reservoir 50 is the element located furthest downstream of the system 1 in the direction of flow. The arrangement of the latter will be explained later in relation to the second fluid connection element 30.

[0032] The reservoir 10 can therefore be seen as central in that the system 1 can comprise upstream of it the source reservoir 40 and downstream of it the receiving reservoir 50 in the direction of flow.

[0033] The second fluid connection element 30 is, for its part, a means for discharging the fluid F outside the reservoir 10 and therefore forms an outlet channel for the fluid F. It is in fluid communication, via one of its ends, with the receiving reservoir 50. In addition, it is fixed at the second opening 18 of the reservoir. It comprises a fluid discharge orifice 32, a discharge portion 34 and a connecting portion 36 in this order in the direction of flow of the fluid F. It is arranged in a similar manner to the first fluid connection element 10 relative to the reservoir 10, although being oriented differently, and has a similar structure (e.g.: size of the discharge orifice 32, with respect to the platelet release reservoir 10).

[0034] That being said, the geometry of the flow is different at the reservoir 10 / discharge orifice 32 interface, which is essentially explained by the type of singularity. Unlike the injection orifice 22 / reservoir 10 interface, the singularity is due to a sudden narrowing of the section in the direction of flow since the diameter (or periphery of the reservoir 10 where appropriate) is much larger than the diameter of the discharge orifice 32. Given the dimensions of the reservoir 10 and those of the discharge orifice 32, such a singularity would have the effect of further increasing the pressure drop experienced by the fluid F when the latter passes from the reservoir 10 to the second fluid connection element 30, but this phenomenon is attenuated due to the fluid displacement generated by the pumping device 60, as will be described in more detail below.This singularity makes it possible to increase the residence time of the fluid within the reservoir 10 since the sudden narrowing of the section acts as an obstacle for the fluid F which is prevented from leaving the reservoir 10 immediately if not directly from the reservoir. The direct consequence of this is that, the residence time of the fluid F being increased, the formation of turbulence or swirling disturbances within the reservoir 10 is favored.

[0035] Furthermore, the residence time of the fluid F within the reservoir 10 can be further advantageously increased by offsetting the injection orifice 22 relative to the discharge orifice 32. In effect, the injection orifice 22 and the orifice 32, although being carried by two axes and therefore forming a plane, this plane is oblique, that is to say it is neither horizontal nor vertical, as illustrated in the example of the Figure 1b . In this regard, as illustrated in the Figure 1cwhich represents a close-up view of the R region framed at Figure 2band as mentioned previously, the first connection element 20 comprises a longitudinal axis X1. The longitudinal axis X1 is a central axis of the first fluid connection element 20 passing through the injection orifice 22. The second fluid connection element 30, for its part, comprises a longitudinal axis X2 arranged in a similar manner as the longitudinal axis X1 with respect to said second fluid connection element 30. The longitudinal axes X1 and X2 may be intersecting or parallel. For the purposes of increasing the residence time of the fluid F and increasing the vortex disturbances, said longitudinal axes are advantageously separated by a non-zero distance, d. This configuration also allows “bubble-free” filling of the reservoir 10. Indeed, the fluid F enters through the injection orifice 22, by suction, and exits through the discharge orifice once all the air contained in said reservoir 10 has been sucked out.

[0036] The discharge orifice 32 is thus separated by a non-zero distance, d, from the injection orifice 22 in a Y-axis direction, the Y-axis being orthogonal to the longitudinal axes X1 and X2. Preferably, the distance, d, is between 3 and 4 mm. That being said, if said orifices 22, 32 can be separated by a distance d in the Y-axis direction, it is not excluded that they are separated by a distance d' in a X-axis direction in the same plane and / or in an XZ plane, the Z-axis being orthogonal to the X-axis in the direction of the sectional section (exiting from the plane of the figure). In this, the sectional view of the Figure 1c may be misleading since the first 16 and second 18 openings and respectively the injection orifice 22 and discharge orifice 32 may be located in different cutting planes (orthogonal to the Z axis).

[0037] If the flow geometry depends substantially on the singularities previously described and therefore on the shape of the elements, it also depends on the flow velocity. The shape of the elements of device 2 and the flow velocity thus act in synergy to obtain such a flow geometry and allow a continuous release of P platelets from the Mk megakaryocytic cells with an improved efficiency compared to known devices. We will return to this later.

[0038] In this regard and as previously mentioned, the system 1 is provided with a pumping device 60 (illustrated in Figure 1b). The pumping device 60 is in fluid communication with the platelet release reservoir 10. It allows the fluid F contained in the reservoir 10 to be displaced. The displacement of the fluid may be due to a depression in the device 2, but it may also be due to a discharge of the fluid as will be seen in more detail below. What is important here is that the fluid F can circulate with a greater speed than that which it would have in the absence of the pumping device 60. The pumping device 60 is for example a vacuum pump or generally any device capable of generating a depression or a discharge of fluid in the device 2. For example, the pumping device 60 is a vane pump, but this is in no way limiting within the scope of the present invention.

[0039] The pumping device 60 may also be located upstream of the first fluid connection element 20 in the direction of flow, preferably in the source reservoir 40. In this regard, a pumping device 60 may be provided by fluid transfer or overpressure in the reservoir 40. In this configuration, the fluid F being discharged in the desired direction of flow, it passes successively through the narrowed portion 24, the injection orifice 22, the reservoir 10 and the discharge orifice 32 by adopting a flow geometry resulting from each of the singularities. That said, the use of a pumping device 60 by fluid transfer (gear pump, peristaltic, etc.) could prove detrimental to the release of the platelets since it would probably degrade the megakaryocytic cells before the process has even begun.The use of this type of pumping device 60 is not mandatory since an ejector type device could also be considered. Generally speaking, any type of pumping device 60 can be used with the possible exception of a fluid transfer pump.

[0040] The pumping device 60 may be in fluid communication with the reservoir 10 via the second fluid connection element 30. Preferably, it is located in the receiving reservoir 50. By being thus arranged, the pumping device 60 is therefore located downstream of the second fluid connection element 30 in the direction of flow of the fluid F. This makes it possible to take full advantage of the singularities of the device 2 and improves the process of forming vortex disturbances within the reservoir 10, in particular its cavity 14.

[0041] Let us return to this point with regard to the discharge portion 34 of the second connecting element 30. It can advantageously be flared from the discharge orifice 32 but this is not essential, to allow the formation of vortex disturbances within the reservoir 10. Let us specify that such a flaring of the discharge portion 34 would be due to the fact that its section widens from the discharge orifice 32 of the fluid in the direction of the pumping device 60, i.e. in the direction of flow. The flaring of the discharge portion 34 allows the pumping device 60, when the latter is located downstream of the second connecting element 30, to move the fluid more efficiently.This is simply explained by the fact that the pumping would not be as efficient if the second connecting element 30 had a section equal to that of the discharge orifice 32 over its entire length, its length being defined as the distance between the discharge orifice 32 and another end of said second element 30. Indeed, as mentioned previously, the discharge orifice 32 has a diameter of at most 1 mm. The flaring therefore has no interest other than that of allowing more efficient suction.

[0042] The system 1 further comprises a power supply module 62 for the pumping device 60. The power supply module 62 allows the pumping device 60 to play its driving role and to move the fluid F. In addition, the power supply module 62 also makes it possible to adjust the power delivered by the pumping device 60 and any other useful parameters that a person skilled in the art will appreciate. Moreover, preferably, the power supply module 62 is configured so that the power delivered by the pumping device 60 makes it possible to adjust the speed of movement of the fluid F in the system 1 in order to obtain a fluid flow rate F of between 37 mL / min and 120 mL / min, or even more. However, this is not the only parameter influencing the fluid flow rate as we will see below.The system 1 may also be equipped with a flow meter for controlling the fluid flow in the reservoir 10 as a function of the power delivered by the electrical power supply module 62. For example, such a flow meter could be placed between the source reservoir 40 and the reservoir 10. Furthermore, the electrical power supply module 62 is not necessarily located in the immediate vicinity of the pumping device 60. It may be remote.

[0043] The system 1 further comprises a programming system 70 configured to control the power supply module 62 of the pumping device 60 in order to implement one or more platelet release sequences made so as to generate a continuous flow of the fluid F between said injection orifice 22 and said discharge orifice 32 as well as vortex disturbances within the reservoir 10 causing the fragmentation of the cytoplasmic extensions Ck of the megakaryocytic cells Mk. The programming system 70 comprises at least one or more processors capable of executing a program in order to implement said platelet release sequences. As will be seen later, the platelet release sequences may vary in their durations, their number, etc.That being said, let us specify that if the power supply module 62 can be controlled by means of such a programming system 70 for an industrial application, it can just as easily be controlled manually by an operator.

[0044] In reference to the Figures 2a to 2d , in a second and a third embodiment of the invention, the system 1 comprises, in addition to the first device 2, a plurality of other devices 2' or 2". The other devices 2' and 2" are identical to the device 2 previously described. The dotted arrow lines indicate the direction of movement of the fluid F in the system.

[0045] In the second embodiment of the system 1 according to the invention illustrated in Figures 2a to 2c, the device 2 is connected in series with other devices 2'. The devices 2, 2' are in fluid communication one after the other. Preferably, the number of other devices 2' is between 1 and 4 so that the total number of devices 2, 2' is between 1 and 5. In such a configuration, the system 1 very advantageously makes it possible to multiply the number of singularities and therefore to further improve the platelet release efficiency. Indeed, the number of turbulences within the system 1 is multiplied all the more the more there are other devices 2' so that each time the fluid F passes through another device 2' the platelet release efficiency is increased.

[0046] An example of the realization of such an assembly is illustrated in Figure 2b. It comprises five devices 2, 2' mounted in series. We distinguish the reservoirs 10', the openings 16' (the openings 18' being opposite and not visible). The reservoirs 10' have an outer casing of cubic shape, which does not prevent them from having a cavity 14 of any desired shape, here it is of spherical shape. In the illustrated embodiment, the reservoir 10' is provided with a chimney 9' to evacuate air bubbles. However, this is not obligatory. The connecting elements 20', 30', at least their portions 24', 34' and respective orifices 22', 32' are formed in assembly parts, located on either side of the reservoirs 10'. The orifices 22', 32' are not aligned, i.e. they are offset, relative to each other in the direction of flow of the fluid F, for each other device 2'.

[0047] In this regard, it may also be specified that the reservoir(s) 10, 10', the aforementioned assembly elements and the connecting elements 20, 20', 30, 30' may be manufactured by any suitable manufacturing method known from the state of the art. In this case, the devices 2, 2' were manufactured by 3D printing and assembled by screwing. In this regard, the devices 2, 2' may comprise fastening means to enable their assembly. Preferably, they are made from polyether imide (PEI) resins or photopolymerizable resin (such as those used in dental orthoses). Preferably, it is a material meeting the pharmacopoeia of the country in which the system 1 according to the invention is to be used. The material may thus be certified by the ANSM ( National Agency for the Safety of Medicines and Health Products ), the EMA ( European Medicines Agency ) in France, the PhEU (European Pharmacopoeia) the PMDA ( Pharmaceutical and medical Devices Agency ) in Japan or the FDA ( Food and Drug Administration) and / or the USP (United States Pharmacopoeia) in the United States, etc. For example, for use in the United States, the device may preferably be made of biocompatible materials classified as USP VI, VI designating USP class. The USP class test is one of the most common testing methods for determining the biocompatibility of materials. There are six classes, VI being the most stringent. Class VI testing is intended to certify that there are no harmful reactions or long-term physical effects caused by chemicals released from plastics. Because of these specificities and the fact that 2' devices are enclosed, they are particularly well-suited for fluid processing suitable for medical use.

[0048] Such a configuration is further advantageous in that it makes it possible to improve the efficiency of the system while being optimally arranged. Indeed, instead of providing a pumping device 60 and a power supply 62 per device 2, 2', these elements are shared for two, three or even more devices 2, 2'. Indeed, while the pumping device 60 is in fluid communication with the first device 2 via the second fluid connection element 30 of said first device 2, as seen previously, the other devices 2' are connected directly to the first connection element 20, 20' of the device 2, 2' which precedes them. In other words, only the first device 2 is connected to the pumping device 60.

[0049] Consider for example the first other device 2' directly connected to the first device 2. The second fluid connection element 30' of said first other device 2' is in fluid communication with said first fluid connection element 20 of said first device 2. Preferably, this fluid communication is direct. It is therefore in indirect fluid communication with the pumping device 60 via the first device 2. Now consider the second other device 2' directly connected to the first other device 2'. The second fluid connection element 30' of said second other device 2' is in fluid communication with said first fluid connection element 20' of said first other device 2'. This also applies to the other successive devices 2'.

[0050] Other types of assemblies, i.e. connection of the pumping device 60 to the devices 2, 2' can be envisaged for mounting the devices 2, 2' in series while respecting the inventive concept of the invention.

[0051] Let us specify that, in a manner similar to what was seen for the first embodiment, the system 1 according to this second embodiment comprises, in addition to the pumping device 60, the electrical power supply module 62 of the pumping device 60 and the associated programming system 70. The geometry of the flow is not modified in such a system 1. Indeed, the flow speed is preserved since instead of generating the depression or a backflow in the circuit of a single device 2, it propagates in all of the devices 2'.

[0052] It may then be necessary to adapt the suction or discharge power, depending on the pumping device 60 used, and more precisely to increase it so that sufficient fluid displacement is obtained for the most distant device 2'. However, too high a suction or discharge power risks harming the platelet release efficiency since this efficiency is only optimal in a defined range of fluid flow rate and therefore suction or discharge power. It is therefore appropriate to carry out such an adaptation according to this constraint if the pumping device 60 used does not allow a constant pressure to be maintained in the system 1. Most of the pumping devices currently available on the market generally make it possible to overcome this problem.

[0053] In a similar manner to what was mentioned previously for the pumping device 60, the electrical power supply module 62 and the programming system 70, it is also possible to provide only a single source reservoir 40 and a single receiving reservoir 50 for the entire system 1, whether it comprises one or, where appropriate, a plurality of devices 2. Such an embodiment is for example illustrated in FIG. Figure 2c. In this exemplary embodiment, the source reservoir 40 and the receiving reservoir 50 consist of flexible bags. The source reservoir 40 is in fluid communication with the other device 2' furthest upstream, i.e. the furthest from the first device 2 in the fluid circuit. The receiving reservoir 50 is, in a similar manner to the pumping device 60, in fluid communication with the first device 2 via the second fluid connection element 30. It should be remembered that the pumping device 60 can advantageously be located in the receiving reservoir 50.

[0054] In a third embodiment of the invention illustrated in figure 2d, the system 1 comprises devices 2, 2" connected in parallel, that is to say that the first device 2 is mounted in parallel with other devices 2". In this configuration, the devices 2, 2" are not connected to each other. In other words, they are independent of each other. Each device 2, 2" therefore operates independently of the others. The preferred number of device(s) 2" is not limited. The more the number of devices 2" is increased, the more the quantity of fluid treated can be increased. For example, with a system 1 comprising three devices 2, 2" mounted in parallel, it is possible to treat approximately 3 liters of fluid F per hour, which gives the invention a considerable advantage over the devices known from the prior art. This configuration makes it possible to adapt the number of devices 2, 2" in operation according to the volume of fluid F to be treated.A larger source tank 40 can be provided, but this is not mandatory. Alternatively, for example, a means of continuously delivering the fluid to be treated could be provided.

[0055] However, similarly to the variant embodiment of the Figure 2b , the pumping device 60, the power supply module 62 and the programming system 70 are shared for all of the devices. However, in this case, the pumping device 60 can be, by a set of connectors, put into fluid communication with all of the devices 2, 2". Other types of assemblies can be envisaged to mount the devices 2, 2" in parallel while respecting the inventive concept of the invention.

[0056] Furthermore, the system 1 of the present invention can be adapted so as to integrate additional functionalities, again respecting the inventive concept of the invention. For example, a Y-shaped pipe could be provided at the inlet of the tank 10 which would allow two types of fluid F to circulate and create mixtures within the tank 10, which, as we have seen, is configured to generate vortex disturbances.

[0057] The invention further relates to a method 5 for releasing platelets P from a fluid F comprising megakaryocytic cells Mk comprising cytoplasmic extensions Ck. The method 5 according to the invention makes it possible, as will be seen in detail in the following sections, to fragment megakaryocytic cells, Mk, and / or cytoplasmic extensions, Ck, in order to release the platelets. In this regard, the method 5 is carried out by means of a system 1 as previously described.

[0058] In reference to the Figures 3a and 3b , during a first step 100 of the method 5, a fluid F comprising megakaryocytes Mk is provided. Preferably, the fluid F is stored in a source reservoir 40 provided for this purpose. The fluid F in question is, for example, a fluid taken from a patient, in particular from their bone marrow, or a fluid obtained by cell culture. In any event, this fluid F comprises megakaryocytes Mk and platelets can be released from it. It should nevertheless be noted that whatever the fluid F, the megakaryocytes Mk are suspended in said fluid F and that, depending on the viscosity of the fluid, the megakaryocytes will be distributed differently.

[0059] Given the quantities, let us recall, of industrial fluid F that can be treated and incidentally of platelets that can be released, a preliminary cell culture step can be envisaged in order to obtain the desired quantity of fluid F and precursors (i.e. megakaryocytes). The aim of this cell culture step is on the one hand to allow the maturation of megakaryocytes Mk and on the other hand their multiplication, i.e. their proliferation. Document FR 3 039 166 describes the cell culture process in more detail.

[0060] For example, the Mk megakaryocytes used in fluid F are megakaryocytes derived from immortalized or non-immortalized CD34+ progenitors. The preliminary step of culturing such Mk megakaryocytes may include two phases lasting a total of 11-17 days. During a first phase lasting between 5 and 9 days, the Mk megakaryocytes are cultured with a mixture comprising, for example, the following agents: serum-free culture medium, a cytokine cocktail containing TPO, IL-6 and IL-9 and the AhR antagonist and LDL (Low density lipoprotein intended to stimulate the proliferation of CD34+ cells and engage them in the megakaryocytopoiesis pathway). The AhR advantageously stimulates the maturation of the Mk megakaryocytes.In a second phase of this culture step, which lasts approximately 6-8 days, the cells obtained are cultured with a mixture of SR1 and thrombopoietin, TPO, and possibly other agents as listed above with reference to the first phase. It should be noted that the cells obtained include megakaryocytes but not exclusively. In addition, it should be noted that not all cells give rise to megakaryocytes. These phases can last more or less time depending on the number of cells desired, the agents used, etc.

[0061] This preliminary step will not be described in more detail because it is not the subject of the present invention and does not form part of it, the invention being limited to proposing a method for the release of platelets from fluid F and not a method including any culture step. In any event, at the end of this cell culture phase, proplatelet megakaryocytes are obtained, i.e. megakaryocytes provided with proplatelets. They are simply called Mk megakaryocytes in the present invention for the sake of simplification. Such cells are illustrated in Figure 4a . They comprise a megakaryocytic body with proplatelets forming extensions from the megakaryocytic body. The cytoplasmic extensions are supported by a network of microtubules and terminate in a platelet knob that prefigures the future platelet. The fluid F provided in step 100 comprises such proplatelet megakaryocytes.

[0062] Referring again to the Figures 3a and 3b , the method 5 comprises, following step 100, a step 200 during which the pumping device 60 is electrically powered so as to generate a depression or a discharge at the outlet of the second fluid connection element 30.

[0063] In step 200, the power of the electrical power supply module 62 of the pumping device 60 can be defined so as to adjust the suction or discharge power. More precisely, the power should be adjusted so that the fluid flow rate F obtained is between 37 mL / min and 120 mL / min, or even more. It should be noted that depending on the material from which the device of the system 1 according to the invention is made, the fluid flow rate can be significantly increased. This is in fact the optimal flow rate range for obtaining the highest platelet release yields with the method according to the invention. The power to be applied intrinsically depends on the material used for the pumping device 60.

[0064] In a step 300, the programming system 70 is commanded to initiate one or more platelet release sequences as defined previously. The programming system 70 advantageously controls the power supply module 62. It also controls the durations and number of platelet release sequences P. The platelet release sequences can last as long as the user wishes in order to treat the desired volume of fluid.

[0065] When the programming system 70 is controlled as described in the previous section, the pumping device 62 being powered, a depression or, depending on the configuration, a discharge is generated in the device(s) 2, 2', 2". "Depression" means that the pressure in the device(s) 2, 2', 2" is lower than atmospheric pressure, i.e. that it is / are subjected to a relative vacuum. The "discharge" corresponds to the fact of moving the fluid F by a discharge pump, for example of the ejector type, or a compressor. As a result of this depression or this discharge, a continuous flow of fluid F, i.e. a movement takes place in the system 1 from the source tank 40 to the receiving tank 50.Let us specify that, preferably, the suction or discharge power of the pumping device 60 is kept constant during the method 5 so that the depression, where appropriate the discharge speed, and the fluid flow rate F are also kept substantially constant. However, this does not prevent, during the implementation of the method, this power from being varied within limits allowing the optimal platelet release efficiency to be obtained.

[0066] As soon as the depression or the discharge is generated in the system(s) 2, 2', 2", the fluid passes through different phases ie 302, 304 and 306, which occur continuously as long as the depression or the discharge is maintained, without additional action on the programming system 70. These phases are the direct consequence of the movement of fluid in the system(s) 2, 2', 2". A phase 302 corresponds to the phase preceding the entry of the fluid F into the reservoir 10, a phase 304 corresponds to the phase where the fluid F is in the reservoir 10 and a phase 306 corresponds to the phase following the suction of the fluid F out of the reservoir 10. In other words, the phases 302, 304 and 306 therefore occur in practice simultaneously since when a part of the fluid F is treated, at the same time another part of the fluid F is being treated in the reservoir 10 and yet another part is about to be treated upstream of the reservoir 10, i.e.in the first connection element 20 or in the source reservoir 40, this along the fluid circuit.

[0067] During phase 302, the fluid F is sucked through the first fluid connection element 20. The pressure within the device being kept constant, the speed of the fluid F increases when it passes through the narrowed portion 24, due to the very fact of the flaring of said narrowed portion 24. The fluid F is then forced into the reservoir 10 via the injection orifice 22. The singularity due to the sudden widening of the section present at the injection orifice 22 / reservoir 10 interface causes the fluid F to slow down when it enters the reservoir 10.

[0068] During phase 304, the fluid F circulates in the reservoir 10 while being subjected to the depression or the discharge generated by the pumping device 60 within the limits of the cavity 14. Indeed, although the fluid has been slowed down by the singularity existing at the orifice 22 / reservoir 10 interface, it remains in motion due to this depression or discharge. The fluid does not leave the reservoir directly, which allows the circulation of said fluid in the form of vortex disturbances. Indeed, the system 1 is configured so that the residence time of the fluid F in the reservoir 10 is sufficient to generate disturbances. As we have seen previously, a sufficient residence time is obtained thanks to the singularity due to the large dimensions of the reservoir 10 relative to the discharge orifice 32.The residence time can also be increased, but to a lesser extent, by advantageously offsetting the injection orifice 22 relative to the discharge orifice 32 on the path of the fluid F as explained below.

[0069] Under these conditions, vortex disturbances of sizes roughly equivalent to those of the megakaryocytes are generated. They fragment the megakaryocytes Mk and their cytoplasmic extensions Ck (proplatelets), which has the effect of releasing the platelets P. Concomitantly, other products Dk resulting from the fragmentation of the megakaryocytes are produced. These products correspond to proplatelet tips, bodies of megakaryocytes MK still intact or pieces of cytoplasm. Since the fluid F is treated continuously over time, for each platelet release sequence, the phenomena described above are reproduced continuously and the platelets are released continuously.In sum, while the fluid F entering the reservoir 10 comprises megakaryocytic cells Mk comprising cytoplasmic extensions, the fluid F leaving the reservoir 10 essentially comprises platelets P and the other products, Dk. In this regard, the use of a system 1 comprising devices 2, 2' in series, as illustrated in . Figures 2a to 2c , advantageously allows the proportions of megakaryocytes still intact to be reduced following process 5. Let us recall that each time the fluid F circulates in a device 2', it undergoes disturbances, hence the higher yields of a system 1 in series in comparison with a system 1 comprising a single device 2.

[0070] During phase 306, the fluid F, loaded with platelets P and other products Dk resulting from the fragmentation of the megakaryocytes, is sucked through the discharge orifice 32 and more generally through the second fluid connection element 30. It then reaches the receiving reservoir 50, if applicable, and the pumping device 60.

[0071] During a step 400, the sequence(s) are stopped by stopping the power supply module 62 by means of the programming system 70.

[0072] These phases occur identically in all other devices 2' and / or 2" possibly present in the system 1 according to the invention.

[0073] In order to release the platelets, the fluid flow rate should preferably be between 37 mL / min and 120 mL / min, or even higher. These flow rate values ​​are average values ​​representing the mean of six measurements. Figure 5aillustrates the evolution of the number of platelets for a number of calibration tubes (BD Trucoun ®< Tubes) or counting tubes equal to 5000 as a function of the relative vacuum generated by implementing the method according to the invention (grey bars) and by means of a pipette (black bar). The relative vacuum is notably expressed in kilo Pascal (kPa). When no depression or backflow is generated in the device(s) 2, 2', 2", the platelet release efficiency remains very low (very light grey). With a relative vacuum equal to -10 kPa, the minimum value of 37 mL / min previously mentioned is obtained. With such a relative vacuum, the platelet release efficiency increases and the number of platelets released exceeds 10,000 for 5000 tubes. This platelet release efficiency is still relatively low. The higher the relative vacuum, the higher the platelet release efficiency.When the relative vacuum is equal to -30 kPa, the previously mentioned value of 120 mL / min is obtained. The number of platelets released is greater than 20,000 per 5,000 megakaryocyte tubes. As illustrated in the . Figure 5a , the platelet release efficiency thus obtained is close to and even higher than that obtained using a conventional manual pipette. This clearly illustrates the importance of the depression or the backflow of fluid generated in the system 1 in order to obtain a satisfactory release efficiency. If in the embodiment example presented here the relative vacuum is -30 kPa, it can be increased beyond -30 kPa, i.e. up to 50 kPa. The fluid flow rate obtained is then significantly higher than 120 mL / min.

[0074] This is explained by the characteristics of the device(s) 2, 2', 2" used in the present embodiment. Indeed, to adjust the flow rate, a compromise must be found between the suction or discharge power of the pumping device 60, the sizes of the injection orifices 22 and 32 for discharge, but also the surface condition of the elements of the device(s) 2, 2', 2" through which the fluid F actually passes, this within the limits of the invention. Concerning this last aspect, the more the surface condition (micro roughness, roughness, etc.) will have the effect of exerting constraints on the fluid F and the more it will be slowed down and vice versa. In order to obtain an even higher platelet release efficiency, it will be possible for example to adjust the surface condition.This can be done by modifying the material used to manufacture the elements of the device(s) 2, 2', 2" through which the fluid F passes, by using other manufacturing processes allowing control of the structuring at the micrometric scale but also by infusing a compound into the chamber such as plasma or albumin.

[0075] There Figure 5b presents an analysis of the functionality of platelets obtained at a pressure of -30 kPa for native platelets (hollow bars) and cultured platelets (solid bars). With this relative vacuum, approximately 8% of native platelets and 10% of non-activated cultured platelets express the GP11b / 111a glycoprotein. Approximately 12% of native platelets and 16% of cultured platelets activated with a CRP-like agonist ( Collagen Related Peptide ) express the glycoprotein GPIIb / IIIa. Finally, nearly 30% of native platelets and 22% of cultured platelets activated with a TRAP-type agonist ( Trombin Receptor-Activating Peptides ) express the Glycoprotein GPIIb / IIIa. The platelets obtained by the method according to the invention are therefore well activated and consequently functional.

Claims

1. A system (1) for releasing platelets from a fluid (F) comprising in particular megakaryocytic cells (Mk) comprising cytoplasmic extensions (Ck), said system (1) comprising: - a device (2) comprising: ∘ a platelet release reservoir (10) comprising a first opening (16) and a second opening (18), ∘ a first fluidic connecting element (20) attached at the level of said first opening (16) and adapted to inject said fluid (F) into said reservoir (10), said first connecting element (20) comprising an orifice (22) for injecting the fluid into the platelet release reservoir (10) and a portion (24) narrowing towards said orifice (22), there being an abrupt widening of cross-section between the injection orifice (22) and the reservoir (10), ∘ a second fluidic connecting element (30) attached at the level of said second opening (18), said second connecting element (30) comprising an orifice (32) for discharging the fluid, - a device (60) for pumping the fluid (F) in fluidic communication with the reservoir (10) by means of the second fluidic connecting element (30) or the first fluidic connecting element (20), - a power supply module (62) for the pumping device (60), - a programming system (70) configured to control the power supply module (62) for the pumping device (60), to implement one or more platelet release sequences designed to generate a continuous flow of the fluid (F) between said injection orifice (22) and said discharge orifice (32) and vortex disturbances within the reservoir (10) causing the fragmentation of the cytoplasmic extensions (Ck) of the megakaryocytic cells (Mk).

2. The system (1) according to claim 1, wherein the narrowing portion (24) is conical.

3. The system (1) according to claim 1, wherein the first connecting element (20) comprises a longitudinal axis (X1) and the second connecting element (30) comprises a longitudinal axis (X2), said longitudinal axes (X1, X2) being either intersecting or parallel and then separated by a non-zero distance, d.

4. The system (1) according to any one of the preceding claims, wherein the injection orifice (22) has an opening diameter of less than 1 mm, a ratio of the opening diameter of the injection orifice (22) by a sectional width of the reservoir (10) is between 0.02 and 0.1.

5. The system (1) according to claim 4, wherein the ratio of the opening diameter of the injection orifice (22) to the cross-sectional width of the reservoir (10) is 0.05.

6. The system (1) according to any one of the preceding claims, wherein the discharge orifice (32) has an opening diameter of less than 1 mm, a ratio of the opening diameter of the discharge orifice (32) to a sectional width of the reservoir (10) is between 0.02 and 0.1.

7. The system (1) according to claim 6, wherein the ratio of the opening diameter of the discharge orifice (32) to the cross-sectional width of the reservoir (10) is 0.05.

8. The system (1) according to any one of the preceding claims, wherein the reservoir (10) has a spherical shape.

9. The system (1) according to any of the preceding claims, comprising: - a source reservoir (40) for the storage of the fluid (F), connected to the first fluidic connecting element (20) for supplying the reservoir (10) and - a reservoir (50) for receiving the fluid (F) connected to the second fluidic connecting element (30) to collect said fluid intended to be sucked from the reservoir (10).

10. The system (1) according to claim 9, wherein the pumping device (60) is located in the receiving reservoir (50).

11. The system (1) according to any one of the preceding claims, wherein said second connecting element (30) further comprises a portion (34) flared from said orifice (32) for discharging the fluid towards the pumping device (60).

12. The system (1) according to one of the preceding claims comprising at least one other device (2") comprising: - a platelet release reservoir (10") comprising a first opening (16") and a second opening (18"), - a first fluidic connecting element (20") attached at the level of said first opening (16") and adapted to inject said fluid (F) inside said reservoir (10"), said first connecting element (20") comprising an orifice (22") for injecting the fluid and a first narrowing portion (24") so as to be able to accelerate the fluid (F), said first narrowing portion (24") opening onto said injection orifice (22"), - a second fluidic connecting element (30") attached at the level of said second opening (18"), said second connecting element (30") comprising an orifice (32") for discharging the fluid, said other device (2") being arranged parallel to the first device (2) and connected to the pumping device by means of the second element (30') of said other device.

13. The system (1) according to any of claims 1 to 11 comprising at least one other device (2') comprising: - a platelet release reservoir (10') comprising a first opening (16') and a second opening (18'), - a first fluidic connecting element (20') attached at the level of said first opening (16') and adapted to inject said fluid (F) inside said reservoir (10'), said first connecting element (20') comprising an orifice (22') for injecting the fluid and a first narrowing portion (24') so as to be able to accelerate the fluid (F), said first narrowing portion (24') opening out on said injection orifice (22'), - a second fluidic connecting element (30') attached at the level of said second opening (18'), said second connecting element (30') comprising an orifice (32') for discharging the fluid, said other device being arranged in series with the first device (2), said second connecting element (30') of said other device (2') being in fluidic communication with said first fluidic connecting element (20) of said first device (2).

14. A method (5) for releasing platelets (P) from a fluid (F) comprising in particular megakaryocytic cells (Mk) comprising cytoplasmic extensions (Ck), said method comprising the following steps, implemented by means of a system (1) according to one of the claims 1 to 13: (100) providing a fluid (F) comprising megakaryocytic cells (Mk) suspended in said fluid (F), said megakaryocytic cells (Mk) comprising cytoplasmic extensions (Ck), (200) electrically powering the pumping device (60), (300) controlling the programming system (70) to initiate one or more platelet release sequences, the or each platelet release sequence being carried out so as to generate a continuous flow of the fluid (F) between said injection orifice (22) and said discharge orifice (32) and vortex disturbances within the reservoir (10) causing the fragmentation of the cytoplasmic extensions (Ck) of the megakaryocytic cells (Mk).

15. The method (5) according to claim 14, wherein during the step (200) a relative vacuum of between -10 kPa and -50 kPa is generated in the device (2, 2', 2").