FLOW CYPTOMETRY DEVICE WITH AN OPTICAL DETECTION SYSTEM, ESPECIALLY FOR THE TREATMENT OF SPERM CELLS

Description

FIELD OF INVENTION

[0001] The invention relates generally to flow cytometry, particularly for the processing of sperm cells, and in particular for the sexing of animal semen, for example bovine.

[0002] The invention relates more particularly to a flow cytometry installation comprising an optical detection system configured to differentiate animal semen cells. TECHNOLOGICAL BACKGROUND

[0003] Flow cytometry installations with optical detection systems configured to differentiate animal semen cells have been known for many years.

[0004] These facilities allow cells, particularly sperm, to be sorted in order to isolate cells with an X chromosome from those with a Y chromosome.

[0005] These installations are typically equipped with a feeding device configured to generate a jet of cells from a nozzle, an optical detection system configured to examine the jet of cells to differentiate the cell type, and a sorting device configured to apply a predetermined load to each differentiated cell, the predetermined load being associated with the result of the differentiation, i.e., the cell type, as well as collection containers for the differentiated and sorted cells.

[0006] Such installations are known in Anglo-Saxon terminology as "jet-in-air sorter".

[0007] It should be noted that these installations are also equipped with control units connected to the power supply, optical detection system, and sorting device. These units are configured to process information representing specific parameters in order to control and manage the devices and systems to which they are connected. These parameters may, for example, correspond to the cell jet flow rate, cell types, or predetermined loads associated with them.

[0008] Optical detection systems in flow cytometry facilities are generally based on fluorescence technologies and are equipped with an excitation laser configured to emit a beam of light and a beam-shaping device that is configured to focus the beam of light to where the cell stream passes.

[0009] These optical detection systems for flow cytometry installations are also equipped with collection elements and detection elements arranged both in a direction of emission of the laser beam and in a direction orthogonal to the direction of emission of the laser beam.

[0010] In such optical detection systems for flow cytometry installations, the detection elements are photomultiplier type sensors, while the collection elements are optical equipment of the microscopic lens type, offering very high magnification, in particular on the order of 50.

[0011] These optical detection systems for flow cytometry installations need to be adjusted to achieve the desired result, namely to differentiate cells in order to sort them.

[0012] In practice, however, the necessary adjustments are complex because it is particularly difficult to make the laser's focal point coincide with the focal points of the very high magnification collection organs, and also with the cell jet, or even with the cells inside the cell jet.

[0013] It should be noted that it is often necessary to degrade the calibration of these optical detection systems to achieve alignment of the focal points with the cell stream, which is particularly unfortunate given the cost of the equipment these systems comprise. A flow cytometer conforming to the prior art is described in patent application US2018095022A1. SUBJECT OF THE INVENTION

[0014] The invention aims to provide a flow cytometry installation, particularly for the processing of sperm-type cells, comprising an optical detection system that is particularly convenient and efficient, both in its adjustment and in use, while also being particularly economical.

[0015] The invention proposes for this purpose, in a first aspect, a flow cytometry installation, in particular for the processing of spermatozoon-type cells and in particular for the sexing of animal semen, comprising an optical detection system configured to differentiate, according to predetermined parameters, a plurality of cells in a jet of such cells directed towards a differentiation zone, said optical detection system being provided with a light radiation source configured to emit light radiation focused on said differentiation zone, at least one detection organ configured to detect a quantity of light re-emitted by said cells which are illuminated, and at least one collection organ which is focused, on a first side, on said differentiation zone and on a second side opposite said first side, on said at least one detection organ;characterized in that said optical detection system is configured such that said at least one collection element has a magnification of less than 10 and said at least one detection element has a vision zone having an area at least 10 times greater than an area of ​​the cell jet at the location of said differentiation zone.;

[0016] In other words, the flow cytometry system according to the invention is equipped with an optical detection system having at least one collection element with a particularly low magnification, much lower than the magnifications used, for example, in microscopy as in the prior art referred to above. It should be noted that this type of optical equipment has the advantage of being much less expensive than that used in microscopy.

[0017] Moreover, the flow cytometry installation according to the invention is equipped with an optical detection system having at least one detection organ whose vision area is much larger than the surface of the cell jet, without this impacting the actual differentiation of the cells.

[0018] The present invention is based on the principle that what is important is to collect the light re-emitted by the illuminated cells in the differentiation zone. This involves detecting light flux. It does not involve capturing an image of the illuminated cells.

[0019] This is made possible in the installation according to the invention because said at least one detection organ has the ability to detect, in the middle of a large surface (here the vision zone), particular elements (here cells) which emit more light than others.

[0020] It is therefore simply a matter of detecting that some cells emit more light than others in order to differentiate these cells.

[0021] Note for example that light radiation can induce fluorescence on cells, so the detection organ is configured to detect an amount of light re-emitted for example by fluorescence or diffusion.

[0022] In other words, the present invention shows that it is not necessary to zoom in heavily on the differentiation area and therefore on the cells (which are particularly small) in order to fill the surface of the vision area of ​​the sensing organ to better differentiate these cells.

[0023] Moreover, in the installation according to the invention, the use of at least one collecting organ with low magnification makes it possible to have a very large field of vision and therefore a very large latitude for focusing.

[0024] In particular, the focusing distance is very large so that it is particularly convenient to arrange the components of the optical detection system so that the differentiation zone, where in particular the focused light beam and the cell jet are located, can always be seen in the vision area of ​​the detection organ.

[0025] In other words, the setup of the installation according to the invention is not complicated and the positioning of the cell jet allows for a certain tolerance, for example up to + / - 1 mm. Such a tolerance was not conceivable in the prior art.

[0026] According to simple, convenient and economical features of the installation according to the invention, said magnification of said at least one collecting organ is less than 8, preferably less than 5, and even more preferably less than 2; while the ratio of said surface of said viewing area of ​​said at least one detecting organ to said surface of said cell jet is between about 10 and about 1000, preferably between 50 and 500, even more preferably between 150 and 350, and even more preferably about 250.

[0027] Other simple, convenient and economical features of the installation according to the invention are presented below.

[0028] Said at least one collecting organ has a first biconvex lens arranged on said first side and focused on said differentiation zone, a second biconvex lens arranged on said second side and focused on said at least one detection organ, and optionally a filtering element interposed between said first and second biconvex lenses.

[0029] The first biconvex lens is configured to collect the light re-emitted by the cells illuminated by the light source in the differentiation zone, and the second biconvex lens is configured to focus the collected light towards the vision zone of at least one sensing organ.

[0030] Said at least one detection device is a sensitive photoelectric detector, for example a photomultiplier or a photodiode.

[0031] The said optical detection system comprises two collection elements and two detection elements, one of said collection elements and one of said detection elements being arranged in a direction of emission of said light beam, and the other of said collection elements and the other of said detection elements being arranged in a direction orthogonal to said direction of emission of said light beam.

[0032] The said source of light radiation is a laser.

[0033] The said optical detection system further comprises a device for shaping said light ray from said source, which device has a beam expander, a cylindrical lens for shaping said ray and a converging lens focusing said enlarged and shaped light ray towards said differentiation zone.

[0034] The said cylindrical lens has a focal length between approximately 1 m and approximately 5 m, and preferably equal to approximately 3 m.

[0035] The installation includes a feeding device configured to generate said cell jet and direct it to said differentiation zone, which feeding device is at least partially mobile independently of said optical detection system.

[0036] The said feeding device comprises a chamber having a first cavity provided for receiving a sheath fluid and a second cavity extending from said first cavity, an injection needle for said cells which is housed at least partially in said chamber and which opens into said second cavity, at the level of which said cells and said sheath fluid meet to form said cell jet, as well as a positioning member configured to move together at least said chamber and said injection needle in at least one direction of movement.

[0037] The positioning device is configured to move the chamber and the injection needle along the direction of emission of the light beam from the light source and / or along the direction orthogonal to the direction of emission of the light beam from the light source, so as to position the cell jet in a predetermined position within the differentiation zone. It should be noted that this positioning is particularly simple and convenient because, as mentioned above, the field of view of the detection device is much larger than the differentiation zone and the cell jet itself (this also corroborates the wide focusing latitude).

[0038] The said positioning device is further configured to move said chamber and said injection needle in rotation so as to orient said cells in said cell jet.

[0039] The said predetermined parameters for differentiating said plurality of cells in a said batch of such cells are the X and Y chromosomes.

[0040] The invention also proposes, in a second aspect, a method of processing by flow cytometry, in particular of cells of the spermatozoon type and in particular for the sexing of animal semen, using an installation as described above, comprising a first stage of centering on said differentiation zone, by means of an optical skeleton, said focused light radiation from said light radiation source and said at least one collection organ.

[0041] It should be noted that such an adjustment of the optical detection system is particularly simple using an optical skeleton, which classically corresponds to a pre-assembled metal structure which allows the different optical components to be positioned in predetermined positions and to be verified, using targets, that the different focal points of these optical components coincide in the differentiation zone.

[0042] According to simple, convenient and economical features of the method according to the invention, said installation includes a feeding device configured to generate said cell jet and direct it towards said differentiation zone, which feeding device is at least partially mobile independently of said optical detection system; and said method includes a second stage of centering said cell jet on said differentiation zone, independently of said first centering stage.

[0043] It should be noted that such an adjustment of the cell jet is also particularly simple since there is no need to move, at the same time as the chamber and the injection needle, the optical detection system which is then fixed. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The exposition of the invention will now be continued by the detailed description of examples of embodiment, given below by way of illustration and not limitation, with reference to the attached drawings. There figure 1 This schematically and partially illustrates, in perspective, a flow cytometry installation specifically for processing sperm cells and, in particular, for sexing animal semen. figure 2 schematically illustrates, in a top view, an optical detection system for the installation of the figure 1 . There figure 3This schematically illustrates a magnified view of the focusing of a laser beam from an optical detection system with a cell jet, viewed from above. figure 4 This schematically illustrates a magnified view of the focusing of a laser beam from an optical detection system with a cell jet, viewed from the front. figure 5 This schematically illustrates, in a top view, a collection element and a detection element of the optical detection system, from the focal point of the laser beam which coincides with the cell jet to a vision zone of the detection element, as well as a magnification of the interior of this vision zone. figure 6 is a view quite similar to that of the figure 5 showing the influence of a displacement of the cell jet relative to the focal point of the laser beam. DETAILED DESCRIPTION OF ACHIEVED EXAMPLES

[0045] There figure 1illustrates a flow cytometry installation 1, in particular here for the sexing of animal semen, especially bovine.

[0046] Of course, it could be animal semen for animals other than cattle, for example horses, or pigs, or sheep or other animals.

[0047] Animal semen sexing refers to the differentiation and sorting of sperm-type cells, based on the chromosome they contain.

[0048] In particular, differentiation is based on predetermined parameters to differentiate a plurality of cells 26 in a jet 11 of such cells, and these parameters are the X and Y chromosomes that spermatozoa may contain.

[0049] Installation 1 described below is of the "jet-in-air sorter" type in Anglo-Saxon terminology.

[0050] Installation 1 includes a feeding device 2 configured to generate a jet 11 from a plurality of cells 26 and direct it to a differentiation zone 17 of installation 1.

[0051] The supply device 2 may include a chamber 6 having a first cavity 9 intended to receive a sheath fluid via supply conduits 8 which open into this first cavity 9, and a second cavity 10 extending the first cavity 9 on the side of an outlet orifice of the chamber directed towards the differentiation zone 17.

[0052] The feeding device 1 may further include an injection needle 7 intended to receive the cells 26 via an additional feeding conduit (not shown).

[0053] The injection needle 7 is housed at least partially in the chamber 6 and opens into the second cavity 10, where the cells 26 are distributed by this needle 7.

[0054] It is in this second cavity 10 that the cells 26 and the sheath fluid meet to form the cell jet 11.

[0055] The feeding device 2 may further include a positioning member 35 configured to move the chamber 6 and the injection needle 7 together in one or more directions of movement (see below).

[0056] For example, it could be a positioning device 35 consisting of a micrometric screw and pivot mechanism.

[0057] Installation 1 further includes an optical detection system 3 which is configured to examine the jet of cells 11 in order to differentiate the type of cell.

[0058] In particular, the optical detection system 3 is configured here to differentiate, according to the chromosomal parameters X and Y, a plurality of cells 26 in the jet of such cells 11 directed towards the differentiation zone 17. Note that the cells 26 to be observed can re-emit light by fluorescence to allow their differentiation.

[0059] The optical detection system 3 can be provided with a light radiation source 12 configured to emit a light beam 16 focused on the differentiation zone 17. This can, for example, be a laser.

[0060] The optical detection system 3 may include a device 13 for shaping the light beam 16 coming from the source 12.

[0061] The optical detection system 3 may further include two detection organs 14 configured to detect an amount of light re-emitted, here by fluorescence, by the illuminated cells 26.

[0062] The optical detection system 3 can also include two collection elements 15 which are focused, on the first side, on the differentiation zone 17 and on the second side opposite to the first side, on the respective detection elements 14.

[0063] One of the collection organs 15 and one of the detection organs 14 are here arranged in the direction of emission of the light beam 16, so as to collect a first re-emitted light beam 18, substantially in the main axis of the light beam 16.

[0064] The other of the collection organs 15 and the other of the detection organs 14 are arranged in the direction orthogonal to the direction of emission of the light ray 16, so as to collect a second re-emitted light beam 19, substantially perpendicular to the main axis of the light ray 16.

[0065] Note that the positioning element 35 of the power supply device 2 is configured here so that the power supply device 2 is at least partially mobile independently of the rest of the installation 1, and in particular with respect to the optical detection system 3.

[0066] In particular, the positioning member 35 can be configured to move the chamber 6 and the injection needle 7 according to the direction of emission of the light beam 16 from the light radiation source 12.

[0067] The positioning member 35 can also be configured to move the chamber 6 and the injection needle 7 in the direction orthogonal to the direction of emission of the light beam 16 from the light radiation source 12.

[0068] Such movements make it possible in particular to position the jet of cells 11 in a determined position in the differentiation zone 17.

[0069] Installation 1 may also include a sorting device 4 configured to apply a predetermined load to each differentiated cell 26.

[0070] The predetermined charge is associated with the result of differentiation, in other words with the cell type, X or Y.

[0071] The sorting device 4 may for example include conductive plates 20 configured to form electrodes which are capable of positively or negatively charging the differentiated cells 26, depending on the result of the differentiation.

[0072] The sorting device 4 is also configured to guide the differentiated and loaded cells towards collection containers 21 configured to receive the sorted cells 26.

[0073] Here, the installation 1 comprises three collection containers 21 configured to receive three cell streams 26 respectively, of which a first stream 23 corresponds for example to positively charged cells identified as Y, a second stream 24 corresponds for example to negatively charged cells identified as X, and a third stream 25 corresponds to uncharged and undifferentiated cells.

[0074] Installation 1 may also include one or more control and command units (not shown) which are connected to the power supply device 2, the optical detection system 3 and the sorting device 4, and which are configured to process certain information representative of certain parameters in order to control and command the devices and system to which they are connected.

[0075] These parameters can, for example, correspond to the cell jet flow rate, the cell types, or the predetermined loads associated with them.

[0076] There figure 2 illustrates optical detection system 3 in more detail.

[0077] As mentioned above, the light source 12 is here a laser.

[0078] The light ray shaping device 13 may have a beam enlarger, a cylindrical lens and a converging lens 28 focusing the enlarged light ray 16 towards the differentiation zone 17. The cylindrical lens may have a focal length of about 3 m.

[0079] Such a cylindrical lens makes it possible in particular to generate two focusing lines perpendicular and about 1 mm apart from the focal point of the converging lens 28, which is located in the differentiation zone 17.

[0080] This therefore makes it possible to generate a light beam whose end has the shape of a segment in the differentiation zone 17 (see below).

[0081] Note that on the figure 2 , the expander, or enlarger, and the cylindrical lens are located in the block referenced 1" to identify the shaping device.

[0082] As also explained above, one of the collection organs 15 and one of the detection organs 14 are arranged in the direction of emission of the light ray 16; while the other of the collection organs 15 and the other of the detection organs 14 are arranged in the direction orthogonal to the direction of emission of the light ray 16.

[0083] Each of the collecting organs 15 can present a first biconvex lens 29 arranged on one side and focused on the differentiation zone 17.

[0084] The first biconvex lenses 29 are configured to collect the light re-emitted by the cells 26 illuminated by the light radiation source 12 in the differentiation zone 17, namely to collect respectively the first re-emitted light beam 18 and the second re-emitted light beam 19.

[0085] Each of the collection organs 15 may have a second biconvex lens 30 arranged on a second side, opposite to the first side, and focused on the respective detection organs 14.

[0086] A filtering element 31 can be interposed between the first and second biconvex lenses 29 and 30 of the collection organ 15 which is arranged in the direction of emission of the light ray 16, in the first re-emitted light beam 18.

[0087] The filtration element 31 is configured to filter the light radiation from the source 12 and transmit the fluorescence re-emitted by the cells 26 and forming the first re-emitted light beam 18.

[0088] The second biconvex lenses 30 are configured to focus the collected, or even filtered, light towards a vision zone of the respective detection organs 14.

[0089] The detection elements 14 are here photomultipliers or photodiodes and are provided, as indicated above, with a vision zone 32 ( figure 5 ) having a predetermined surface area.

[0090] THE figures 3 and 4 illustrate in detail the interaction between the light ray 16 focused by the cylindrical lens and the converging lens 28 and the cells 26 in the cell jet 11, at the level of the differentiation zone 17.

[0091] The cell jet 11 has a dimension of approximately 50 to approximately 100 microns in diameter and the cells 26 have a size of approximately 10 microns.

[0092] As explained above, the end of the light beam 16 has the shape of a segment 27, substantially elliptical, whose great length is here approximately equal to the diameter of the cell jet 11.

[0093] In other words, the focal point of the light beam 16 is "elongated", in the form of a line, to promote the illumination of the cells 26 in the jet of cells 11 when they pass through the differentiation zone 17, regardless of the position of the cells 26 in the jet of cells 11.

[0094] It should also be noted that the positioning member 35 of the feeding device 2 can also be configured to move the chamber 6 and the injection needle 7 in rotation so as to orient the cells 26 in the jet of cells 11, so that the latter are arranged perpendicular to the incident light beam.

[0095] There figure 5 illustrates in detail what happens after the differentiation zone 17 and in particular what is detected by the detection organ 14 which is located in the direction of emission of the light beam 16.

[0096] Note that this is therefore the first re-emitted light beam 18; but that the principle is essentially the same for the second re-emitted light beam 19 detected by the detection organ 14 which is in the direction orthogonal to the direction of emission of the light beam 16.

[0097] The optical detection system 3 is configured so that the collecting organs 15, and in particular the first and second biconvex lenses 29 and 30, have a magnification of only 2 here.

[0098] This magnification of 2 is to be compared with the size of the cells, on the order of 10 microns, and with the diameter of the cell jet 11, on the order of 50 to 100 microns, for example 70 microns.

[0099] The optical detection system 3 is further configured so that the detection organs 14 have a vision area 32 having an area 34 at least 10 times greater than an area 33 of the cell jet 11, and up to 1,000 times greater, but preferably about 250 times greater.

[0100] This is particularly visible on the right side of the figure 5 where the surface 33 of the jet of cell 11 is much smaller than the surface 34 of the vision zone 32 of the detection organ 14.

[0101] Such a ratio between the surface 34 of the vision zone 32 of the detection organ 34 and the surface 33 of the cell jet 11 makes it possible to ensure that the cell jet 11 and therefore the cells 26 which will cross the laser segment 27 in the differentiation zone 17, and consequently the light re-emitted by these cells 26 and collected can be detected.

[0102] Indeed, as shown by the "virtual" representation on the figure 5 , all these elements, including the cell jet 11', the cell 26' and the laser segment 27', are largely found in the vision zone 32 of the detection organ 14.

[0103] This further corroborates the fact that the focusing distance is very large and therefore the adjustment of installation 1 is particularly simple.

[0104] For example, to get out of the vision zone 32 of the detection organ 14, the supply device 2 would have to be translated by a distance on the order of a millimeter in the direction orthogonal to the direction of emission of the light beam.

[0105] The same is true on the focal axis, or in other words, in the direction of emission of the light ray. This is illustrated on the figure 6 where we can see that a defocus, in other words a displacement X- or X+ of the jet 11 of a value A microns relative to a reference X, introduces a very slight defocus Y- or Y+ of the order of B microns in the vision zone 32 of the detection organ 14. For example, if the value A is equal to about 10 microns, the value B may be equal to only about 40 microns.

[0106] It should also be noted that the amount of light recovered by the detection organs 14 is linked to the numerical aperture and not to the magnification.

[0107] Here, since the collection organs 14 and detection organs 15 are arranged along the first and second re-emitted light beams, which are substantially perpendicular to each other, the theoretical maximum numerical aperture is about 0.7.

[0108] In practice, the numerical aperture could be between approximately 0.5 and 0.7, or preferably it could be equal to approximately 0.65.

[0109] The installation 1 described above is particularly convenient also in that it greatly simplifies the process of processing by flow cytometry, in particular of sperm-type cells and especially for the sexing of animal semen, using this installation 1.

[0110] Indeed, the process includes a first step of centering on the differentiation zone 17, by means of an optical skeleton, the focused light ray 16 coming from the light radiation source 12 and also from the collection organs 14.

[0111] Note that such a centering step can be likened to an adjustment of the optical detection system 3. This adjustment is particularly simple using an optical skeleton, which classically corresponds to a pre-assembled metal structure which allows the different optical components to be positioned in predetermined positions and to be verified, using targets, that the different focal points of these optical components coincide in the differentiation zone.

[0112] The aim is therefore to avoid having to make complex optical adjustments before the installation can be used for cell processing.

[0113] Note that the detection of the light re-emitted by the cell is optimal when the cell crosses the laser segment at its center and at the exact point of focus in the differentiation zone, and also that this cell is itself at the focus of the two collection organs 14.

[0114] To do this, all that remains is to adjust the cell jet with respect to the differentiation zone, and therefore with respect to the optical skeleton which is centered on this differentiation zone where the different focal points of the aforementioned optical components coincide.

[0115] The process therefore includes a second step of centering the jet of cells 11 on the differentiation zone 17, independently of the first centering step.

[0116] It should be noted that such an adjustment of the cell jet is also particularly simple since the installation 2 and in particular the positioning member 35 allows the chamber 6 and the injection needle 7 to be moved together, without moving the optical detection system 3, which is then fixed.

[0117] Alternatively, the collection organ(s) may have a magnification of less than 8, preferably less than 5, or preferably less than 2, or even less than 1.

[0118] More specifically, within the aforementioned limits, the collecting organ(s) may have a magnification between 1 and 5, or between 5 and 8, or even more precisely between 1 and 3 or between 1 and 2; or even more precisely a magnification of the order of 1 rather than 2, or of the order of 0.5, 3, 4, 5, 6, 7, 8, or even 9.

[0119] Alternatively, the ratio of the area of ​​the vision zone of the detection organ(s) to the area of ​​the cell jet can be between approximately 10 and approximately 1000, preferably between 50 and 500, preferably again between 150 and 350.

[0120] Variants not shown are described below.

[0121] The installation could include only one pair of collection / detection organs or, on the contrary, more than two pairs of collection / detection organs, for example three, four, five or six, or even more.

[0122] The light source can be, for example, a diode laser or LED laser source.

[0123] The light source may be different from a laser source.

[0124] The cylindrical lens of the light beam shaping device has a focal length of between approximately 1 m and approximately 5 m.

[0125] Many other variations are possible depending on the circumstances, and it should be noted in this regard that the invention is not limited to the examples described and represented.

Claims

1. Flow cytometry installation, in particular for treating sperm type cells and more particularly for sexing animal semen, comprising an optical detection system (3) configured to differentiate, according to predetermined parameters, a plurality of cells (26) in a jet of such cells (11) directed towards a differentiation zone (17), said optical detection system being provided with a source of light radiation (12) configured to emit light radiation (16) focused on said differentiation zone (17), at least one detector (14) configured to detect an amount of light re-emitted by said cells (26) that are illuminated, and with at least one collector (15) that is focused, at a first side, on said differentiation zone (17) and at a second side which is an opposite side to said first side, on said at least one detector (14), said optical detection system being configured such that said at least one collector (15) has a magnification less than 10; and characterized in that said at least one detector (14) has a zone of vision (32) having a surface area (34) at least 10 times greater than a surface area of the jet of cells (11) at the location of said differentiation zone (17).

2. Installation according to claim 1, characterized in that said magnification of said at least one collector (15) is less than 8, preferably less than 5, and more preferably less than 2; while the ratio of said surface area (34) of said zone of vision (32) of said at least one detector (14) to said surface area of said jet of cells (11) is comprised between approximately 10 and approximately 1000, preferably between 50 and 500, more preferably between 150 and 350, and more preferably is equal to approximately 250.

3. Installation according to one of claims 1 and 2, characterized in that said at least one collector (15) has a first biconvex lens (29) arranged on said first side and focused on said differentiation zone (17), a second biconvex lens (30) arranged on said second side and focused on said at least one detector (14), and optionally a filter member (31) interposed between said first and second biconvex lenses (29, 30).

4. Installation according to claim 3, characterized in that said first biconvex lens (29) is configured to collect the light emitted by said cells (26) illuminated by said source of light radiation (12) in said differentiation zone (17), and said second biconvex lens (30) is configured to focus said collected light towards said zone of vision (32) of said at least one detector (14).

5. Installation according to any one of claims 1 to 4, characterized in that said at least one detector (14) is a photomultiplier.

6. Installation according to any one of claims 1 to 5, characterized in that said optical detection system (3) comprises two collectors (15) and two detectors (14), of which one of said collectors (15) and one of said detectors (14) are disposed in an emission direction of said light radiation (16), and of which the other of said collectors (15) and the other of said detectors (14) are disposed in a direction at a right angle to said emission direction of said light radiation (16).

7. Installation according to any one of claims 1 to 6, characterized in that said source of light radiation(12) is a laser.

8. Installation according to any one of claims 1 to 7, characterized in that said optical detection system (3) further comprises a shaping device (13) for shaping said light radiation (16) coming from said source (12), which device (13) has a radiation expander, a cylindrical lens for shaping said radiation and a convergent lens (28) focusing said magnified and shaped light radiation (16) towards said differentiation zone (17).

9. Installation according to claim 8, characterized in that said cylindrical lens has a focal length comprised between approximately 1 m and approximately 5 m, and preferably equal to approximately 3 m.

10. Installation according to any one of claims 1 to 9, characterized in that it comprises a supply device (2) configured to generate said jet of cells (11) and direct it towards said differentiation zone (17), which supply device (2) is at least partly movable independently of said optical detection system (3).

11. Installation according to claim 10, characterized in that said supply device (2) comprises a chamber (6) having a first cavity (9) provided to receive a sheath fluid and a second cavity (10) extending said first cavity (9), a needle (7) for injecting said cells (26) which is housed at least partly in said chamber (6) and which is open to said second cavity (10), at the location of which said cells (26) and said sheath fluid meet to form said jet of cells (11), as well as a positioning member (35) configured to move together with each other at least said chamber (6) and said injection needle (7) in at least one direction of movement.

12. Installation according to claim 11, characterized in that said positioning member (35) is configured to move said chamber (6) and said injection needle (7) in the direction of emission of the light radiation (16) coming from said source of light radiation (12) and / or in the direction at a right angle to the direction of emission of the light radiation (16) coming from said source of light radiation(12); so as to position said jet of cells (11) in a defined position in said differentiation zone (17).

13. Installation according to one of claims 11 and 12, characterized in that said positioning member (35) is furthermore configured to move said chamber (6) and said injection needle (7) rotationally so as to orient said cells (26) in said jet of cells (11).

14. Installation according to any one of claims 1 to 13, characterized in that said predetermined parameters for differentiating said plurality of cells (26) in a said jet of such cells (11) are the X and Y chromosomes.

15. Method of treating, by flow cytometry, in particular cells of sperm type, more particularly for sexing animal semen, using an installation according to any one of claims 1 to 14, characterized in that it comprises a first step of centering, on said differentiation zone, via an optical skeleton, the focused light radiation coming from said light radiation source and from said at least one collector.

16. Method according to claim 15, characterized in that said installation comprises a supply device (2) configured to generate said jet of cells (11) and direct it towards said differentiation zone (17), which supply device (2) is at least partly movable independently of said optical detection system (3); and said method comprises a second step of centering said jet of cells (11) on said differentiation zone (17), independently of said first centering step.