Tip for a sampling pipette

Abstract

The invention relates to a pipette tip (1, 1') comprising at least one wall portion (2, 2') having a conical shape that is rotationally symmetrical about axis (R), characterized in that said wall portion (2, 2') comprises at least one first wall (20, 20') continuing on a periphery of at least one portion of an inner surface, said first wall projecting from a base (200, 200') in contact with said inner surface to a vertex (201, 201') at an angle of between 40° and 140° with respect to said wall portion (2, 2').

Description

[0001] DESCRIPTION

[0002] TITLE: TIP FOR SAMPLING PIPETTE

[0003] Field of invention

[0004] The invention relates to the field of sampling pipettes, also known as laboratory pipettes or liquid transfer pipettes, for collecting and dispensing a sample of a liquid into containers or the like.

[0005] More particularly, the invention relates to a pipette tip, suitable for manually operated pipettes, motorized pipettes, or automated pipetting machines.

[0006] State of the Art

[0007] For many years, the design of manually, motorized or automatically operated pipettes (otherwise known as pipetting systems) has been the subject of numerous improvements aimed at simplifying their design, minimizing implementation costs, or improving their operation.

[0008] One of the classic problems in the field of pipettes is the flow of liquid within the pipette in order to optimize sampling and dispensing operations, while limiting contamination between the different samples.

[0009] It is thus known to develop solutions relating to pipette consumables, and in particular to the tip, in order to maximize the ratio between the liquid collected and the liquid dispensed in order not to distort samples, to limit liquid losses, and to limit contamination between the different samples.

[0010] Known solutions involve chemical surface treatments on the tip after its manufacture by plastic injection or topological surface texturing before or after the manufacture of the tip by plastic injection so as to lower the surface energy of the polymer, the constituent material of the sampling tip, and thus limit the liquid retained in the sampling tip by the internal walls.

[0011] However, such surface treatments, even if they may be effective from a static physics point of view, do not take into account the aspects relating to the dynamics of the flow of the liquid at the interface with the solid during the two critical phases of suction of the liquid into the sampling tip and distribution of the liquid from the sampling tip.

[0012] Indeed, a surface can have hydrophobic, superhydrophobic, oleophobic or superoleophobic characteristics under static measurement conditions, but can be hydrophilic, superhydrophilic, oleophilic or superoleophilic under conditions of use, in the state immersed by liquid present in the pipette tip.

[0013] Maintaining a so-called Cassie-Baxter state, so that the liquid drops remain at the top of the roughness of a treated surface during dynamic movement of the liquid, is therefore difficult to obtain due to these characteristics varying according to the static or dynamic regime.

[0014] To counter this problem, it is known to use tips with conical walls with internal surfaces including occasional peaks and troughs.

[0015] However, a disadvantage of these interior surfaces bearing deformations is that the liquid, during its movement, can easily penetrate and wet the hollows of the texture due to the Wenzel state, that is, the ease of adaptation and wetting to the morphology of the surface.

[0016] Furthermore, this state, observed on flat surfaces, is all the more exacerbated when the pressure exerted by the fluid on the surface is strong, which is typically the case for a liquid confined in a space of small diameter such as the tip.

[0017] There is therefore a need to improve such pipette tips in order to improve the flow of liquid in aspiration and dispensing and to better control the flow rate of the liquid, whether to retain it or accelerate it.

[0018] Statement of the invention

[0019] The invention aims to remedy at least in part the drawbacks mentioned above relating to the techniques of the prior art.

[0020] To this end, the invention relates to a pipette tip, comprising at least one conical wall of revolution of axis R. According to the invention, the wall portion comprises, on at least part of an interior surface, at least one first wall extending in projection from a base in contact with said interior surface to a vertex at an angle of between 40° and 140° relative to said wall.

[0021] Thus, the invention proposes a new and inventive approach making it possible to at least partially resolve some of the drawbacks of the prior art by the fact that the tip has, on at least a part of an inner surface of a portion of conical wall, a microtextured surface with protrusions making it possible to trap air pockets near the deformations, and thus the liquid circulating in the tip is at least partially in contact with air and not entirely with the walls of the tip. As a result, the interactions between the liquid and the walls of the tip are limited and, consequently, the risks of liquid retention on the inner surface of the wall of the tip are limited. As a result, a tip is obtained having a portion of wall which is hydrophobic or even superhydrophobic, or oleophobic or even superoleophobic, in dynamic flow.

[0022] Additionally, it also allows for better control of the flow rate by slowing down, or accelerating, the liquid.

[0023] According to one aspect of at least one embodiment of the invention, the at least one first wall extends over the entire perimeter of the interior surface of the wall portion.

[0024] In this case, according to one aspect of at least one embodiment of the invention, the at least one first wall may have a circular shape, i.e. form a circle around a circumference of the inner surface of the wall portion.

[0025] According to another aspect of at least one embodiment of the invention, the end piece may comprise, on at least a portion of an interior surface of said wall, several walls forming a plurality of circles spaced longitudinally, along the length of the end piece.

[0026] According to another aspect of at least one embodiment of the invention, the tip may comprise a wall forming a spiral on the interior surface of the tip, along a longitudinal axis of the tip.

[0027] According to one aspect of at least one embodiment of the invention, said at least one first wall has a height h between said base and said top, less than 80 pm, preferably between 1 pm and 50 pm, still preferably between 5 pm and 20 pm.

[0028] According to one aspect of at least one embodiment of the invention, said at least one first wall has a first width at the location of said base of between 1 pm and 20 pm, and a second width at the location of said top of between 0.1 pm and 10 pm.

[0029] In this way, it gives the possibility of implementing a wall that can have different shapes.

[0030] For example, this allows the implementation of a triangular shaped wall to facilitate demolding when making the end piece. This also allows the implementation of different triangular shapes depending on the uses.

[0031] A wall with a rounded shape at the top could also be planned.

[0032] According to one aspect of at least one embodiment of the invention, the end piece has a plurality of first walls, the apex S of each of the first walls being spaced from the apex S of an adjacent wall by a distance of less than 200 pm, preferably between 10 pm and 80 pm. In addition, the end piece comprises at least one channel, each channel being delimited by the spacing between two first walls.

[0033] Such a spacing is large enough for air to become trapped between two first walls. According to a particular aspect of at least one embodiment, the end piece comprises, on at least a portion of an inner surface of said wall portion, a plurality of second walls extending projecting from a base in contact with said inner surface to a top along generatrices of the end piece, said second walls intersecting said first walls, thus forming a plurality of cavities, each cavity being delimited by the intersection between two adjacent first walls and two adjacent second walls.

[0034] According to a particular aspect of at least one embodiment, said first walls are distributed around the periphery of said inner surface of said wall portion and said second walls are distributed around the periphery of said inner surface of said wall portion, each of the cavities comprising a volume of between 100 pm 3 and 3,200*10 3 pm 3 .

[0035] According to a particular aspect of at least one embodiment, said first walls are distributed uniformly around the periphery of said inner surface of said wall portion and said second walls are distributed uniformly around the periphery of said inner surface of said wall portion, each of the cavities having a uniform volume of between 100 pm 3 and 3,200*10 3 pm 3 .

[0036] The invention also relates to a pin for an injection mold configured for the plastic injection molding of a pipette tip according to one of the aforementioned embodiments, said pin comprising a portion of wall of conical shape of revolution of axis R comprising, on at least a first conical section of an outer surface at least a first groove hollowed out from said outer surface to a bottom at an angle of between 40 and 140° relative to said outer surface, on the periphery of the outer surface.

[0037] According to a particular aspect of at least one embodiment, said pin comprises at least one second groove hollowed out from said outer surface to a bottom along generatrices of the pin.

[0038] The invention also relates to a method for manufacturing a pin for an injection mold according to one of the aforementioned embodiments, the method comprising a step of forming at least one groove by micro electro-erosion, by laser, by micro-milling, by ion beam, or by 3D printing.

[0039] The invention also relates to a method of manufacturing a pipette tip according to one of the aforementioned embodiments, by plastic injection using a plastic injection mold carrying at least one conical pin according to one of the aforementioned embodiments.

[0040] List of figures The invention, as well as the various advantages that it presents, will be more easily understood in the light of the following description of an illustrative and non-limiting embodiment thereof, and of the appended drawings among which:

[0041] Figure 1 is a perspective view of a pipette according to one embodiment of the invention;

[0042] Figure 2 is a perspective view of a pipette tip according to one embodiment of the invention;

[0043] Figure 3 is a side sectional view of the tip of Figure 2;

[0044] Figure 4a is another side sectional view of the tip of Figure 2;

[0045] Figure 4b is a detailed view of a portion of the tip of Figure 4a;

[0046] Figure 4c is a detailed view of a portion of the tip of Figure 4b;

[0047] Figure 5 is a detailed view of a portion of the tip of Figure 4c;

[0048] Figure 6 is a detailed view of a portion of a tip according to a second embodiment;

[0049] Figure 7 is a detailed view of a cavity according to the embodiment of Figure 6;

[0050] Figure 8a is a view of a spindle according to a first embodiment of the invention;

[0051] Figure 8b is a detailed view of a portion of the spindle of Figure 8a;

[0052] Figure 9a is a view of a spindle according to a second embodiment of the invention, and

[0053] Figure 9b is a detailed view of part of the spindle of Figure 9a.

[0054] Detailed description of an embodiment of the invention

[0055] The general principle of the invention is based on the implementation of non-point protuberances on a periphery of at least part of an interior surface of the wall of a pipette tip so as to maintain a so-called Cassie-Baxter state, and therefore so that the drops of liquid remain at the top of the protuberances during dynamic movement of the liquid.

[0056] A first embodiment of the invention is now presented in relation to Figures 1 to 5.

[0057] Manual pipettes are designed to be held in the hand by an operator during liquid collection and dispensing operations. For mechanical manual pipettes, these operations are performed by moving a pipetting control button, obtained by applying actuating pressure to this same button which is mechanically transferred to a control rod. On motorized pipettes, the operator's control pressure on the control button generates a signal that is transmitted to the pipette's control unit, so that it triggers the movement of the control rod via a motor embedded in the pipette. As for automated pipetting machines, they are placed on the laboratory bench and a control system generates the signal that is transmitted to the control unit of the automaton, so that it triggers the movement of the pipetting unit via a motor.

[0058] It should be noted that pipettes, whether manual, motorized, or automatic, can be air displacement pipettes or positive displacement pipettes. Positive displacement pipettes are used with syringe-type tips where the liquid is in direct contact with the plunger. In this case, the plunger is part of the tip and is discarded after use.

[0059] In the case of air displacement pipettes, the liquid is never in contact with the piston, which is located inside the lower part of the pipette, in the tip holder. Figure 1 illustrates a mechanical manual pipette 100 with air displacement having a body 101 surmounted by a pipetting control button 103. The body 101 is extended by a pipetting head 102 carrying, at its end, a tip 1.

[0060] According to the invention, the end piece, illustrated more particularly in figures 2 to 6, comprises a portion of wall 2 of conical shape of revolution of axis R.

[0061] More particularly, this portion of wall has a section decreasing towards an outlet end 3 of the liquid from the pipette.

[0062] In other embodiments, the entire wall of the tip could be conical in shape.

[0063] The wall portion 2 of the tip 1 comprises an outer surface, and an inner surface intended to be in contact with liquid taken or to be dispensed.

[0064] According to the invention, the end piece 1 comprises at least one first wall 20 extending around a periphery of at least part of the inner surface of the wall portion 2.

[0065] This first wall 20 extends in projection from a base 200 in contact with the interior surface to a top 201 at an angle of between 40° and 140° relative to the wall portion 2.

[0066] In the illustrated embodiment, and as seen in particular in FIG. 5, the first wall 20 extends in projection from a base 200 in contact with the inner surface of the wall portion 2 to a top 201 at an angle substantially equal to 90° relative to the wall 2.

[0067] Thus, such a pipette tip 1 makes it possible to trap air pockets near the first wall 20, and thus the liquid circulating in the tip is at least partially in contact with air and not entirely with the inner surface of the tip. As a result, the interactions between the liquid and the walls of the tip are limited and, consequently, the risks of liquid retention on the inner surface of the wall portion 2 of the tip 1 are limited.

[0068] In the illustrated embodiment, the interior surface of the wall portion 2 comprises several first walls 20, two of which are shown in FIG. 5. In the illustrated embodiment, each of the first walls 20 has a height h, between the base 200 and the top 201, of between 5 pm and 20 pm.

[0069] Generally speaking, each of the first walls has a height, between the base and the top, less than 80pm, preferably between 1pm and 50pm.

[0070] Furthermore, in the illustrated embodiment, each of the first walls 20 has a first width b of between 1 pm and 20 pm, and a second width c at the location of the vertex 201 of between 0.01 pm and 10 pm.

[0071] Furthermore, in the illustrated embodiment, each of the first walls 20 has a third width at mid-height a, corresponding to a height at 0.5h, between 0.1b and 0.6b.

[0072] Therefore, in this embodiment, the first walls have a substantially triangular profile.

[0073] The advantage of having such a shape for the first walls is that during manufacturing, for example by plastic injection molding, the demolding operations are facilitated.

[0074] According to other embodiments, it could be provided that the first walls have a rectangular or trapezoidal shape.

[0075] Each of these first walls 20 extends over the entire perimeter of the interior surface of the wall portion 2, and has a circular shape.

[0076] In this way, and due to the conical shape of the wall portion, the inner surface has a plurality of first walls spaced longitudinally and forming circles of different diameters on the inner surface of the wall portion 2.

[0077] The longitudinal spacing f between two first walls can be considered as the spacing between two vertices 201 of two adjacent first walls, and can preferably be between 100 pm and 80 pm.

[0078] Furthermore, between two first walls, the end piece comprises at least one channel, each channel being delimited by the spacing between two first walls 20.

[0079] Generally, the top 201 of each of the first walls 20 is spaced from the top 201 of an adjacent wall by a distance of less than 200 pm.

[0080] Furthermore, such a longitudinal spacing f allows the liquid, during a dynamic movement, to come into contact with the first walls and dip a height d of the first walls, avoiding coming into contact with the inner surface of the wall portion 2. This longitudinal spacing therefore allows to have a height m between the top 201 of the wall and the bottom of the meniscus which is less than 0.99h.

[0081] In other words, the liquid meniscus forming between two walls has a height m less than the height h so as not to touch the inner surface of the wall portion 2. According to an alternative of this embodiment, the tip could comprise a single first wall forming a spiral on the inner surface of the tip, along a longitudinal axis of the tip.

[0082] According to another alternative of this embodiment, the tip could comprise several portions of first walls aligned on the same altitude of the periphery of the interior surface of the tip.

[0083] A second embodiment of the invention is now presented in relation to Figures 6 and 7.

[0084] In this embodiment, the tip 1' for a pipette, comprising a portion of wall 2' of conical shape of revolution of axis R, with, as for the first embodiment, several first walls 20' developing on a periphery of a part of an interior surface of the wall 2', the first wall extending in projection from a base in contact with the interior surface to a summit at an angle of between 40° and 140° relative to the wall 2'.

[0085] In this second embodiment, the end piece further comprises, on at least a portion of an interior surface of the wall portion 2', a plurality of second walls 21' extending projecting from a base 210' in contact with the interior surface to a top 211' along generatrices of the end piece, these second walls intersecting the first walls 20'.

[0086] As a result, the end piece comprises a plurality of cavities 23', each cavity being delimited by the intersection between two adjacent first walls 20' and two adjacent second walls 21'.

[0087] In this second embodiment, the first walls 20' are not distributed uniformly around the perimeter of the inner surface of the wall portion 2' and the second walls 21' are distributed uniformly around the perimeter of the inner surface of the wall 2'. A central strip 24' remains free of any walls.

[0088] Here, each of the cavities 23' comprises a substantially equal volume of between 100 pm 3 and 3,200*10 3 pm 3 .

[0089] According to other embodiments, the first walls 20' could be distributed uniformly around the perimeter of the inner surface of the wall portion 2' and / or the second walls could be distributed uniformly around the perimeter of the inner surface of the wall 2'.

[0090] We now present, in relation to Figures 8a and 8b, a first embodiment of a pin for an injection mold configured for the plastic injection molding of a tip 1 for a pipette. As illustrated, this pin comprises a wall portion of conical shape of revolution of axis R comprising, on at least a first section 90 of an outer surface at least one first groove 91 hollowed from the outer surface to a bottom at an angle of between 40 and 140° relative to the outer surface, on the periphery of the outer surface. More particularly, in this embodiment, this pin comprises a plurality of first grooves 91 hollowed from the outer surface to a bottom at an angle of between 40 and 140° relative to the outer surface.

[0091] We now present, in relation to figures 9a and 9b, a second embodiment of a pin for an injection mold configured for the plastic injection molding of a tip 1 for a pipette. As illustrated, this pin 9' comprises a portion of wall of conical shape of revolution of axis R comprising, on at least a first section 90' of an outer surface at least a first groove 91' hollowed from the outer surface to a bottom at an angle of between 40 and 140° relative to the outer surface, on the periphery of the outer surface.

[0092] More particularly, in this embodiment, this pin comprises a plurality of first grooves 91' hollowed out from the outer surface to a bottom at an angle of between 40 and 140° relative to the outer surface.

[0093] Furthermore, the spindle of this second embodiment comprises on at least a first conical section of an outer surface at least one second groove 92' hollowed out from the outer surface to a bottom at an angle of between 40 and 140° relative to the outer surface, along generatrices of the spindle.

[0094] More particularly, in this second embodiment, the spindle comprises a plurality of second grooves 92' hollowed out from said outer surface to a bottom along generatrices of the spindle.

[0095] Such a pin according to one of the embodiments described above makes it possible to implement a method of manufacturing a pipette tip by plastic injection using a plastic injection mold comprising at least one pin.

[0096] It should be noted that this injection mold pin can be manufactured by means of a process comprising a step of forming at least one groove by micro electro-erosion, by laser, by micro-milling, by ion beam, or by 3D printing.

Claims

CLAIMS

1. Tip (1, 1') for a pipette, comprising at least one wall portion (2, 2') of conical shape of revolution of axis (R), said wall portion (2, 2') comprising a plurality of first walls (20, 20'), each developing on a periphery of at least a part of an interior surface, each of said first walls extending in projection from a base (200, 200') in contact with said interior surface to a vertex (201, 201') at an angle of between 40° and 140° relative to said wall portion (2, 2'), the vertex (201, 201') of each of said first walls (20, 20') being spaced from the vertex (201, 201') of an adjacent wall by a distance of less than 200 pm, preferably between 10 pm and 80pm, said end piece comprising at least one channel, each channel being delimited by the spacing between two first walls (20, 20'), characterized in that said end piece comprises, on at least part of an interior surface of said wall portion (2'),a plurality of second walls (21') extending projecting from a base (210') in contact with said inner surface to a top (211') along generatrices of said end piece (1'), said second walls (21') intersecting said first walls (20'), said end piece comprising a plurality of cavities (23'), each cavity being delimited by the intersection between two adjacent first walls (20') and two adjacent second walls (21').,

2. Tip (1, 1') for pipette according to claim 1, characterized in that each of said first walls (20, 20') extends over the entire perimeter of said inner surface of said wall portion.

3. Tip (1, 1') for pipette according to one of the preceding claims, characterized in that each of said first walls (20, 20') has a height (h), between said base (200, 200') and said top (201, 201'), less than 80 pm, preferably between 1 pm and 50 pm, still preferably between 5 pm and 20 pm.

4. Tip (1, 1') for pipette according to one of the preceding claims, characterized in that each of said first walls (20, 20') has a first width at the location of said base (200, 200') of between 1 pm and 20 pm, and a second width at the location of said top (201, 201') of between 0.01 pm and 10 pm.

5. Tip (1') for pipette according to one of the preceding claims, characterized in that said first walls (20') are distributed around the periphery of said inner surface of said wall portion (2') and said second walls (21') are distributed around the periphery of said inner surface of said wall portion (2'), each of the cavities (23') comprising a volume of between 100 pm 3 and 3,200*10 3 pm 3 .

6. Spindle for injection mold configured for plastic injection molding of a tip (1, l') for a pipette according to one of claims 1 to 5, characterized in that said spindle comprises at least one portion of wall of conical shape of revolution of axis (R) comprising, on at least a first conical section of an outer surface at least one first groove hollowed from said outer surface to a bottom at an angle of between 40 and 140° relative to said outer surface, on the periphery of the outer surface.

7. A spindle according to claim 6, configured for plastic injection molding of a tip (1') for a pipette according to one of claims 1 to 5, characterized in that said spindle comprises at least one second groove hollowed from said outer surface to a bottom along generatrices of the spindle.

8. Method for manufacturing a pin for an injection mold according to one of claims 6 or 7, characterized in that it comprises a step of forming at least one groove by micro electro-erosion, by laser, by micro-milling, by ion beam, or by 3D printing.

9. Method of manufacturing a tip (1, 1') for a pipette according to one of claims 1 to 5 by plastic injection using a plastic injection mold comprising at least one pin according to one of claims 6 or 7.

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