LIQUID-METERING DEVICE FOR BALLISTICALLY DISCHARGING METERED AMOUNTS IN THE NANOLITER RANGE, LIQUID-METERING METHOD AND PIPETTING TIP THEREFOR

Abstract

A liquid-metering device for discharging metered liquid in the nanometer range, includes a pipetting-tip receiving device defining, at least in a metering-ready operating position of the liquid-metering device, a receiving space that runs along a virtual receiving axis and is designed to receive a portion of a pipetting-tip. The liquid-metering device also includes a triggering plunger moveable relative to the pipetting-tip receiving device, between a standby position and a triggering position. The liquid-metering device also includes movement drive, which is coupled to the triggering plunger so as to transmit motion, and a control device for controlling operation of the movement drive. A first and second deformation formation define therebetween an axial longitudinal region of the receiving space as a deformation region, in which region the first and second formations can be brought closer or farther away to/from one another. The triggering plunger is located in the deformation region.

Claims

1. A liquid-metering device for ballistically dispensing a discrete dosage amount of a dosage liquid in a dosage volume range of 0.3 nl to 900 nl from a dosage liquid supply, comprising: a pipetting-tip mounting device defining in at least one ready-to-use operating position of the liquid-metering device a mounting space extending along a virtual mounting axis that is configured to accommodate a portion of the pipetting tip a release tappet movable relative to the pipetting-tip mounting device, which can be displaced between a standby position further retracted from the mounting space to a release position further projecting into the mounting space, a displacement drive having a motion-transmitting coupling to the release tappet, configured to intermittently displace the release tappet, at least from the standby position to the release position, and a control device connected to the displacement drive for controlling the operation of the displacement drive based on signal transmission, wherein the liquid-metering device comprises a first and a second deformation formation, wherein the first and the second deformation formation define between them an axial longitudinal section of the mounting space as a deformation area, in which the first and second deformation formation can be converged and retracted from each other, wherein the release tappet in its release position is located in the deformation area of the mounting space.

2. The liquid-metering device according to claim 1, wherein the first and second deformation formation are movable relative to each other between a further retracted loading position, in which the pipetting-tip mounting device is configured for at least one of fitting a pipetting tip into the pipetting-tip mounting device and removing a pipetting tip from the pipetting-tip mounting device, and a more converged deformation position, in which a section located in the deformation area of a pipetting tip fitted into the mounting space is deformed by the first and the second deformation formation, wherein the control device is configured to only actuate the release tappet to displace from the standby position to the release position when the first and the second deformation formation are in the deformation position.

3. The liquid-metering device according to claim 1, wherein the liquid-metering device is configured to deform, in the deformation area, a portion of a pipetting tip fitted in the mounting space for the duration of a deformation interval, wherein said deformation interval is longer than the displacement interval of the motion that displaces the release tappet from the standby position to the release position.

4. The liquid-metering device according to claim 1, wherein the release tappet is at least a portion of the first deformation formation and is the first deformation formation.

5. The liquid-metering device according to claim 1, wherein the second deformation formation comprises a wall section delimiting the mounting space.

6. The liquid-metering device according to claim 1, wherein the pipetting-tip mounting device comprises a first device portion, arranged more closely to the release tappet, penetrated or penetrable by the release tappet, and a second device portion further removed from the release tappet, wherein the second device portion can be moved further away from and converged to the first device portion.

5. The liquid-metering device according to claim 5, wherein the second deformation formation is arranged at the second device portion.

8. The liquid-metering device according to one of claim 6, wherein the liquid-metering device comprises an actuating drive coupled to the second device portion, through which the second device portion can be moved between an open position further removed from the first device portion and a closed position more closely converged to the first device portion.

9. The liquid-metering device according to claim 8, wherein the second device portion is pre-tensioned in one of its positions.

10. The liquid-metering device according to claim 1, wherein the release tappet is pre-loaded in one of its positions.

11. The liquid-metering device according to claim 1, wherein the release position of the release tappet is defined by a mechanical stop that is adjustable along the displacement trajectory of the release tappet.

12. The liquid-metering device according to claim 1, wherein a displacement trajectory, along which the release tappet can be displaced between its standby position and its release position, forms an angle in the range of 70 to 110 degrees, with the virtual mounting axis.

13. The liquid-metering device according to claim 6, including the details of claim 6, wherein a motion trajectory, along which the first and second device portion can be converged, forms an angle in the range of 70 to 110 degrees with the virtual mounting axis.

14. The liquid-metering device according to claim 12, wherein the displacement trajectory and the motion trajectory (B) are parallel at least in portions.

15. The liquid-metering device according to claim 1, wherein it further comprises a pipetting tip with a lengthwise coupling end having a coupling formation that is designed for coupling to a pipetting channel of a pipetting device and having a lengthwise metering end opposite to the lengthwise coupling end having a metering orifice, through which the discrete dosage amount can be dispensed, wherein the pipetting tip features a reservoir chamber between the lengthwise coupling end and the lengthwise metering end, in which the dosage liquid supply can be held.

16. The liquid-metering device according to claim 15, wherein the pipetting tip extends between its lengthwise coupling end and its lengthwise metering end along a virtual tip axis, wherein in a fitted condition of the pipetting tip in the mounting space, the pipetting tip, and specifically its reservoir chamber axially protrudes over the deformation area in relation to the tip axis on both sides.

17. The liquid-metering device according to claim 16, wherein the deformation area is arranged more closely to the lengthwise metering end than to the lengthwise coupling end, wherein preferably the deformation area is arranged completely in the half emanating from the lengthwise metering end of the pipetting tip's axial extension area.

18. The liquid-metering device according to claim 15, wherein the pipetting tip in its condition fitted in the mounting space comprises a deformation portion situated in the deformation area having two opposing, interior wall sections across a gap on the inside of the pipetting tip.

19. The liquid-metering device according to claim 18, wherein the release tappet in the release position is in contact with the deformation portion of the pipetting tip.

20. A pipetting device having a pipetting channel extending along a virtual channel trajectory, which is filled at least partly with a working fluid differing from the dosage liquid and which features at its free lengthwise end a coupling formation for the temporary, detachable coupling of a pipetting tip thereto, wherein said pipetting device further comprises: a pressure-adjustment device configured to modify the pressure of the working fluid in the pipetting channel, a pressure sensor, configured and arranged for sensing the pressure of the working fluid, in the pipetting channel, a pipetting control device connected to both the pressure sensor and the pressure-adjustment device through signal transmission for controlling the pressure-adjustment device operation, which is configured to control the operation of the pressure-adjustment device at least in accordance with an actual working fluid pressure sensed by the pressure sensor, and a liquid-metering device according to claim 1, wherein the channel trajectory virtually extending from the pipetting channel is parallel or collinear to the mounting axis.

21. The pipetting device according to claim 20, further comprising a liquid-metering device in accordance with the preceding claims, including the details of claim 15, wherein the pipetting tip with its coupling formation is coupled, or can be coupled, to the coupling feature of the pipetting channel, and wherein the pipetting control device is further configured to control the operation of the pressure-adjustment device at least in accordance with an actual working fluid pressure sensed by the pressure sensor.

22. A pipetting tip for use in a liquid-metering device according to claim 1, which extends along a virtual tip axis, wherein the pipetting tip comprises: a lengthwise coupling end with a coupling formation which is configured to be coupled to the pipetting channel of a pipetting device, a lengthwise metering end end having a metering orifice, arranged at an axial distance from the lengthwise coupling end in relation to the tip axis, through which a discrete dosage amount can be dispensed from a dosage liquid supply held in the pipetting tip, a reservoir chamber between the lengthwise coupling end and the lengthwise metering end, in which the dosage liquid supply can be held, wherein a section arranged between the metering orifice and the coupling formation as a deformation portion features two opposing interior wall surface sections across a gap on the inside of the pipetting tip, wherein said gap in a first extension direction, extending orthogonally to the tip axis and parallel to the opposite interior wall surface sections, has an inside width that is at least five times, as large as that of a second extension direction that extends orthogonally both to the tip axis and to the first extension direction.

23. The pipetting tip according to claim 22, wherein the dimension of the gap along the tip axis is at least 0.5 times its maximum inside width along the first extension direction.

24. The pipetting tip according to claim 22, wherein the dimension of the gap along the tip axis does not exceed 0.8 times of the axial pipetting tip length.

25. The pipetting tip according to claim 22, wherein the pipetting tip comprises, at least on one side of the deformation portion, a rotationally symmetric body section, arranged on each side of the deformation portion.

26. The pipetting tip according to claim 22, wherein the deformation portion along the first extension direction radially protrudes over an axially adjoining body portion of the pipetting tip, relating to the tip axis.

27. The pipetting tip according to claim 22, wherein a body portion of the pipetting tip axially adjoining the deformation portion radially protrudes over the deformation portion along the second extension direction, relating to the tip axis, wherein each of the two body sections axially adjoining the deformation portion on each side protrude over the deformation portion along the second extension direction.

28. A method for ballistically dispensing a discrete dosage amount of a dosage liquid in a dosage volume range of 0.3 nl to 900 nl from a dosage liquid supply, comprising the following steps: provision of a pipetting tip extending along a virtual tip axis and having a coupling formation configured at the axial lengthwise end relating to the tip axis, for coupling to a pipetting device with a metering orifice arranged at an axial distance from the coupling formation for discharging the dosage amount, and having a reservoir chamber located between the coupling formation and the metering orifice for holding the dosage liquid supply, holding a dosage liquid supply in the reservoir chamber, deformation of a portion of the reservoir chamber, including converging the interior wall surface sections of the reservoir chamber arranged at a distance from each other with a converging component extending orthogonally to the tip axis, thus resulting in the formation of a deformation portion of the pipetting tip while the deformation portion is formed and while dosage liquid is held between the interior wall surface sections situated opposite from each other: application of an intermittent impulse on the deformation portion, propelling the dosage amount of dosage liquid through the metering orifice, wherein the duration of the impulse transmission is short compared to the duration of the deformation of the deformation portion.

29. The method according to claim 28, wherein the intermittent impulse transmission comprises a further deformation of the deformation portion protruding over the deformation of the reservoir chamber section to form the deformation portion, wherein the further deformation interval of the deformation portion is short compared to the deformation interval to form the deformation portion.

Description

[0077] The present invention is described in greater detail based on the attached drawings. They show the following:

[0078] FIG. 1 A lateral view of an embodiment according to the invention of a liquid-metering device having a pipetting tip, wherein a first and second device portion of the liquid-metering device are shown in an exploded view as separated from the main body of the device and wherein the pipetting tip is coupled to a pipetting channel of a pipetting device,

[0079] FIG. 2 A perspective view of the embodiment of FIG. 1 without a pipetting device,

[0080] FIG. 3 The embodiment in the view of FIG. 1, with the first and second deformation formation in deformation position, also without a pipetting device,

[0081] FIG. 4 The first and second device portion used in FIGS. 1 to 3, showing a perspective view of its opposing surfaces in operation,

[0082] FIG. 5A View of a conventional, undeformed pipetting tip,

[0083] FIG. 5B Lateral view of the pipetting tip of FIG. 5A, in a condition deformed by the first and second deformation formation,

[0084] FIG. 5C Pipetting tip of FIG. 5A in deformed condition, in a frontal view of the deformation portion.

[0085] In FIGS. 1 to 3, an embodiment according to the invention of a liquid-metering device is generally labeled as 10. The liquid-metering device 10 comprises a housing 12, generally fully mounted for operation, for example affixed to a frame, on which a pipetting-tip mounting device 14 is arranged.

[0086] In the embodiment shown herein, the pipetting-tip mounting device 14 comprises a first device portion 16, generally affixed to a housing or frame, and a second device portion 18 being movable in relation thereto.

[0087] The motion of the second device portion 18 is guided by guiding devices, for example two parallel guide rods 20 and 22, which penetrate the first device portion 16. The second device portion 18 can be moved along a motion trajectory B parallel to the drawing plane of FIG. 1 between an open position further removed from the first device portion 1 (see for example FIGS. 1 and 2) and a closed position arranged more closely to the first device portion 16 (see FIG. 3).

[0088] The liquid-metering device 20 features two manually operable screws 24a and 24b as the actuating drive 24 of the second device portion 18, at least from the open position to the closed position. The second device portion 18 can be converged toward the first device portion 16 with a defined force, using screws 24a and 24b, up to the closed position. In the opposite rotational direction, the second device portion 18 is at least movable along the motion trajectory B in the direction emanating from the first device portion 16. This permits an operator to perform a manual operating intervention at the second device portion 18 by moving the second device portion 18 from the closed to the open position.

[0089] As the average skilled person will easily understand, the actuating drive 24 may feature an actuator instead of the screws 24a and 24b shown in this example, wherein said actuator may be coupled to the second device portion along the motion trajectory B for joint motion. For example, the actuating drive 24 may be a pneumatically or hydraulically actuated drive having a piston rod or multiple piston rods that are coupled to the second device portion for joint motion. Alternatively, the actuating drive 24 may be an electric motor drive, for example a spindle drive, to reflect the operating principle of the screws 24a and 24b shown as examples. To this end, a threaded rod of the spindle drive with a female thread may be connected to an opening penetrating the second device portion 18 parallel to the motion trajectory B in such a way that the second device portion functions as a nut, which, in case of rotation of the at least one threaded rod, is moved along the motion trajectory B along the longitudinal threaded rod axis in accordance with the speed and pitch of the threading used on the threaded rod.

[0090] In contrast to the kinematics described above, the first device portion 16 can be actuated by an actuating drive along the motion trajectory B in addition to the second device portion 18, although this would only increase the number of actuating drives to be configured without yielding significant further benefits.

[0091] As an alternative, the second device portion 18 may be affixed to a housing or frame and only the first device portion 16 may be movable along the motion trajectory B by an actuating drive.

[0092] The further functions and effects of the first and second device portions 16 and 18 are discussed in greater detail below in the context of FIG. 4, but the operating principle of the liquid-metering device 10 will be explained first.

[0093] The liquid-metering device 10 comprises a release tappet 26, which can be moved along a displacement trajectory V between a standby position further retracted into the housing 12 and a release position further projecting from the housing 12. The displacement trajectory V and the motion trajectory B are preferably collinear or at least parallel.

[0094] The stroke of the release tappet 26 between the two aforementioned operating positions is significantly smaller than the relative motion path of the first device portion 16 and the second device portion 18 along the motion trajectory B between their operating positions: open and closed position. While the relative motion path of the first and second device portion 16 and 18 is at least in the single-digit millimeter range, the stroke of the release tappet 26 between the aforementioned operating positions, i.e., standby position and release position, is generally less than 50 μm, preferably less than 40 μm and most preferably less than 36 μm. The information on the stroke of the release tappet as well as on the relative motion path of the first and second device portion 16 and 18 not only applies to the sample embodiment of the present invention as shown in FIGS. 1 to 3, but generally to the liquid-metering device of the present invention. The stroke of the release tappet is preferably always smaller, at least by a factor of about 5 smaller than the motion path of the device portions 16 and 18 between their operating positions.

[0095] To control the motion of the release tappet 26, the liquid-metering device 10 features a control device 28, which is only shown in FIGS. 1 and 3 as a dotted line in the housing 12 for reasons of clarity. The control device 28 has a signal transmission connection with a displacement drive 30, shown as a piezoelectric actuator in this example, through a wire 30.

[0096] The terminals 34a and 34b are able to transmit energy, in this example electrical energy through terminal 34a, as well as data, in this example through terminal 34b in the form of an RJ45 port to the inside of housing 12. The energy can be supplied to the piezoelectric actuator of the displacement drive 30 as actuating energy through the control device 28 via wire 32. In this manner, the release tappet 26 can be displaced, against the pre-tensioned load of a spring 36 setting it back (see FIG. 3) from the housing 12 into the release position by supplying power to the displacement drive 30. By interrupting the power supply of the piezoelectric actuator of displacement drive 30, the release tappet 26 is immediately displaced through the pre-tensioned threaded spring 36 to the standby position more retracted in the housing 12.

[0097] The housing 12 can be spatially aligned in relation to a frame or/and the pipetting device 60 shown in FIG. 1 with the positioning pins 36a and 36b.

[0098] Instead of a piezoelectric actuator, the displacement drive 30 may comprise an electromagnet, which generates, or does not generate, a magnetic field by applying and withholding current, thus causing the release tappet 26 to displace. In the case of an electromagnetic displacement force, the release tappet 26 may comprise a permanent magnet or a magnetically soft anchor, which can be displaced by the magnetic field generated by the electromagnetic displacement drive, depending on its power supply status, along the displacement trajectory V together with the release tappet 26 supporting it.

[0099] The release tappet 26 in the embodiment shown here projects into a recess 38 penetrating the first device portion 16 and penetrates it both in its standby position and its release position.

[0100] The operating principle of the liquid-metering device 10 is explained below based on details of the first device portion 16 and the second device portion 18 shown in FIG. 4.

[0101] The opposing surfaces 16a and 18a of the two device portions 16 and 18 feature a contour which is configured such that, when the two device portions 16 and 18 are in their converged closed position along the motion trajectory B, a mounting space 40 is defined between the two device portions 16 and 18, in which at least an axial portion of the pipetting tip 42 can be fitted. The mounting space 40 extends along a virtual mounting axis A, which coincides with a virtual tip axis S of a pipetting tip 42 fitted into the mounting space 40. The device portions 16 and 18 are in their closed position.

[0102] The release tappet, the first device portion 16 penetrated thereby, and the second device portion 18 comprise deformation formations, which define a deformation area 44 at the pipetting-tip mounting device 14, in which a conventional pipetting tip 42 fitted into the mounting space 40 is mechanically deformed in portions when the first and second device portions 16 or 18 are in the closed position.

[0103] The aforementioned deformation formations comprise a first deformation formation 46, arranged more closely to housing 12, and a second deformation formation 48 arranged at the second device portion 18.

[0104] The first deformation formation 46 comprises a front surface 46a of the release tappet 26 (see FIG. 1), facing the second device portion 18, and a constricted section 46b extending along the mounting axis A arranged at a distance from the penetration opening 38 at the first device portion 16.

[0105] The second deformation formation 48 comprises a substantially level surface 48a, extending orthogonally to the motion trajectory B, at the second device portion 18 and a step section 48b, in which an inside width between the opposing surfaces 16a and 18a of device portions 16 and 18 is tapered in steps in the deformation area 44. Alternatively, the step area 48b may be configured entirely or partly as an inclined surface.

[0106] Since the deformation formation 46 is configured at the release tappet 26 and at the first device portion 16 and since the deformation formation 48 is configured at the second device portion 18 and since the release tappet 26 remains in its standby position at least until the first and second device portion 16 or 18 are in the closed position, the deformation formations 46 and 48 are in a deformation position deforming a fitted pipetting tip 42 when the first and second device portion 16 and 18 are in the closed position and the release tappet 26 is in the standby position. Furthermore, the deformation formations 46 and 48 are in a loading position to facilitate the fitting or retrieval of a pipetting tip 42 from the pipetting-tip mounting device 14 when the first and second device portions 16 and 18 are in the open position. Since the stroke of the release tappet 26 is substantially smaller than the device portions 16 and 18, the position of the release tappet 26 is not relevant. However, it will be in the standby position since the control device 28 is configured to only displace the release tappet 26 only into its release position when the device portions 16 and 18 are in the closed position.

[0107] In its release position, the release tappet 26 projects more into the mounting space 40, particularly in its deformation area 44, than in the standby position.

[0108] During operation, the front surface 46a of the release tappet 26 and the surface 48a of the second device portion 18 oppose each other and define a substantially level gap with a consistent gap dimension to be measured along the motion trajectory B, as shown in the example, over the entire gap area defined by the front surface 46a of the release tappet 26. The front surface 46a of the release tappet 26 and/or the surface 48a of the second deformation formation 48 may be arranged with a contour that differs from a level configuration. However, the use of level surfaces is easier for manufacturing the aforementioned components.

[0109] The constricted section 46b is designed to cause a constriction of a pipetting tip 42 fitted into the mounting space 40 on the side of the penetration opening 38 that is further removed from the metering orifice 50 of the pipetting tip 42. This constriction is designed to reduce the inside width of the pipetting tip 42, which in turn increases the flow resistance of the dosage liquid in the pipetting tip 42 emanating from the deformation area 44 in the direction away from the metering orifice 50. This is to ensure that, when the release tappet 26 mechanically exerts a short mechanical impulse with a duration in the double-digit or low three-digit millisecond range on a deformed portion of the pipetting tip 42 in the deformation area 44 of the pipetting-tip mounting device 14, a resulting pressure wave induced in the dosage liquid held in the pipetting tip 42 causes the discharge of a dosage drop through the metering orifice 50 and does not force the liquid away from the metering orifice 50 toward the increasing cross-sections of the pipetting tip that is conically tapered in the direction of the metering orifice 50.

[0110] The liquid-metering device 10 enables the advantageous use of conventional pipetting tips 42 for metering liquid in dosage amounts in the nanoliter range, although the conventional pipetting tips 42 in their undeformed initial state are only configured for metering liquids in the so-called “air displacement” method, which does not allow for metering in the nanoliter range with the aforementioned metering method. A conventional pipetting tip 42 in its undeformed state prior to fitting a portion of the same into the mounting space 40 of the pipetting-tip mounting device 14 and prior to displacing the device portions 16 and 18 into the closed position is shown in FIGS. 1, 2 and 5A. Such a conventional pipetting tip 42 at its lengthwise metering end 52 features the metering orifice 50 and comprises a coupling formation 56 at the opposite lengthwise coupling end 54 for coupling to a pipetting channel 58 of a pipetting device 60 as shown in FIG. 1.

[0111] The pipetting tip 42, extending along a virtual tip axis S intersecting it in the center, features a reservoir chamber 62 between the lengthwise coupling end 54 and the lengthwise metering end 52, in which a dosage liquid supply can be held, for example through aspiration via the metering orifice 50.

[0112] The aforementioned constricted section 46b in the first device portion 16 forms a constriction in the closed position of the device portions 16 and 18 in the reservoir chamber 62 in the portion of the pipetting tip 42 that protrudes from the gap formed by the release tappet 26 and the surface 48a in the direction of the lengthwise coupling end 54.

[0113] When the pipetting tip 42 is fitted into the mounting space 40 and the device portions 16 and 18 are in the closed position, the deformation area 44 of the pipetting-tip mounting device 14 and the release tappet 26 forms the deformation area 64 at the pipetting tip 42.

[0114] The pipetting tip 42 is preferably configured to be rotationally symmetric in relation to its tip axis S as a rotational symmetry axis in the undeformed condition.

[0115] Since only the deformation portion 64 of the pipetting tip 42 is deformed by the deformation formations 46 and 48, a rotationally symmetric body section 66 or 68 of the pipetting tip 42 is arranged axially on both sides of the deformation portion 64. These rotationally symmetric body sections 66 and 68 are the undeformed sections of the pipetting tip 42 that axially directly adjoin the deformation portion 64.

[0116] FIGS. 5B and 5C show pipetting tips 42 and 42′ with slight differences in deformation, once in a view along the displacement trajectory V (FIG. 5C) and once extending orthogonally both to the displacement trajectory V and the mounting axis A (FIG. 5B).

[0117] As can be discerned by the slightly different deformation of the pipetting tip 42′ in FIG. 5C compared to the pipetting tip 42 of FIG. 5B, the figures show different pipetting tips 42 and 42′. The identical and functionally comparable sections of the pipetting tip 42′ in FIG. 5C therefore show the same references as for the pipetting tip 42 in the remaining figures, but are labeled with an added apostrophe. The embodiment of FIG. 5C is only described in terms of its differences from FIG. 5B, with said description also used for explanation of the embodiment 42′ of FIG. 5C.

[0118] As can be seen in FIG. 5C, the deformation portion 64′, in a first extension direction E1 extending orthogonally to the tip axis S, features a substantially larger dimension than in a second extension direction E2, which is orthogonal to the tip axis S and to the first extension direction E1. This also applies to the deformation portion 64 of the pipetting tip 42. The dimension of the deformation portion 64 or 64′ in the first extension direction E1 is preferably at least five times larger than the dimension in the second extension direction E2.

[0119] In the first extension direction E1, the deformation portion 64 or 64′ protrudes radially over the two undeformed body sections 66 and 68 or 66′ and 68′ that directly adjoin the deformation portion 64 or 64′ axially on both sides relative to the tip axis S.

[0120] Likewise, the pipetting tip 42 or 42′ is deformed radially in the deformation portion 64 or 64′ to such an extent that the undeformed body sections 66 and 68 axially adjoining the deformation portion 64 or 64′ along the second extension direction E2 radially protrude over the deformation portion 64 or 64′.

[0121] When viewing the pipetting tip 42 fitted into the pipetting-tip mounting device 14, the second extension direction E2 extends parallel to the motion trajectory B and thus parallel to the displacement trajectory V. The first extension direction E1 is orthogonal to the second extension direction E2 and orthogonal both to the second extension direction E2 and to the tip axis S or the mounting axis A.

[0122] The deformation portions 64 or 64′ form a gap space on the inside of the pipetting tip 42 or 42′, which features dimensions along the extension directions E1 and E2 that are smaller by the wall thickness of the pipetting tip 42 or 42′ than the deformation portions 64 or 64′ themselves.

[0123] The deformation portion 64 features two level surface sections 64a and 64b, parallel to each other, at least on its outside due to the level and parallel surfaces 46a and 48a it is formed from.

[0124] The gap space formed on the inside by the deformation portion 64 or 64′ can also be formed by level and/or parallel inside surface sections. This is feasible especially if the wall thickness of the pipetting tip 42 or 42′ is constant along its axial extension or at least along the reservoir chamber 62 or 62′.

[0125] The gap space formed on the inside of pipetting tip 42 or 42′ in the deformation portion 64 or 64′ preferably features an inside width of about 100 μm in the second extension direction. This value is only given as an example. In contrast, the gap may have an inside width of 5 mm or more in the first extension direction E1.

[0126] In the pipetting tip 42 or 42′ embodiment shown here, the deformation space 64 or 64′ is formed along the tip axis S with the largest dimension. This also applies to the gap space formed by the deformation portion 64 or 64′. It can be configured to be at least about twice as long along the tip axis S as along the first extension direction El.

[0127] Since the deformation portion 64 or 64′ of the pipetting tip 42 or 42′ is the release section, in which the release tappet 26 transmits a short intermittent mechanical impulse to the dosage liquid held in the pipetting tip 42 or 42′ to ballistically discharge a dosage amount in the nanoliter range through the metering orifice 50 or 50′, the deformation portion 64 or 64′ is preferably arranged more closely to the metering orifice 50 or 50′ than to the coupling formation 56 or 56′.

[0128] Preferably, the deformation portion 64 or 64′ is completely formed by the axial extension half of the pipetting tip 42 emanating from the metering orifice 50.

[0129] Since the pipetting tips 42 or 42′ are disposable pipetting tips that are discarded after a single use to avoid contaminations, the permanent deformation of the pipetting tip 42 or 42′ caused by the deformation formations 46 and 48 during operation is irrelevant.

[0130] The liquid-metering device 10 is ideally suited for aliquoting, for example by using a pulsing operation of the displacement drive 30 via the control device 28.

[0131] The metering of the dosage liquid amounts in the nanoliter range can be further supported by the pipetting device 60 shown as an example and sketched in FIG. 1. For this purpose, the pipetting device 60 with its pipetting channel 58 can be coupled to the coupling formation 56 of the pipetting tip 42 by way of a coupling feature 70 only shown as a sketch in FIG. 1. The pipetting channel 58 holds a gas as a working fluid, with a pressure detectable by a pressure sensor 72.

[0132] The pressure of the working fluid in the pipetting channel 58 can be changed by a pressure-adjustment device 74, which may for instance comprise a pipetting piston 76 held in the pipetting channel 58 along a channel axis K, in the known manner.

[0133] The pressure-adjustment device 74 may feature an adjustment drive 78, through which the pipetting piston 76 is adjustable along the channel axis K in the pipetting channel 58, i.e., through which the pressure of the working fluid in the pipetting channel 58 can be changed. A pipetting control device 80, connected with the pressure sensor 72 as well as with the adjustment drive 78 of the pipetting piston 76 through signal transmission, can effectuate the adjustment of the pipetting piston 76, depending on an actual working fluid pressure measured by pressure sensor 72 and, if applicable, further depending on a target working fluid pressure set in a supply device of the pipetting control device 80, using the corresponding control of the adjustment drive 78.

[0134] The pipetting control device 80 may be connected to the control device 28 of the liquid-metering device 10 via signal transmission.