EP1996522A2

EP1996522A2 - Method and device for producing glass pipettes or glass capillaries

Info

Publication number: EP1996522A2
Application number: EP07723536A
Authority: EP
Inventors: Albrecht Lepple-Wienhues
Original assignee: Flyion GmbH
Current assignee: Flyion GmbH
Priority date: 2006-03-23
Filing date: 2007-03-23
Publication date: 2008-12-03
Also published as: WO2007110202A2; US20090260398A1; WO2007110202A3; DE102006014512A1; US20120204602A1; JP2009531259A

Abstract

The invention relates to a method for producing glass pipettes or glass capillaries. In said method, a pipette or capillary (1) with a conical tip and a tubular section that adjoins the latter is fixed in a retaining device (2), the fixed glass pipette (1) is then introduced into the thermal radiation field of a heating unit (3), the glass pipette is softened at least in the tip region, a gas pressure is applied to the interior of the glass pipette in such a way that the diameter of said pipette is abruptly lengthened by a small amount between the base surface of the cone and the tubular section, the expanded glass pipette (1) is then removed from the thermal radiation field of the heating unit (3) and the abrupt lengthening of the diameter of the glass pipette (1) is verified and preferably controlled with the aid of an optical observation unit (4). The invention also relates to a corresponding device for the production of glass pipettes or glass capillaries (1) consisting of a retaining device, a heating unit, a positioning device, a pressure application unit, an observation unit and a control and verification unit.

Description

description

Method and device for producing glass pipettes or glass capillaries

The invention relates to a method for the production of glass pipettes or glass capillaries and a device for the production of glass pipettes or glass capillaries. The pipettes or capillaries are intended in particular for performing patch-clamp experiments.

As is known, the interior of living cells is surrounded by a lipid membrane which seals off the processes inside the cell from the outside environment. These lipid membranes are largely impermeable to charged particles. For this purpose, special transport proteins embedded in the membranes transport the charged particles (ions) through the membrane. These transport proteins thus form the basis for a variety of physiological functions.

Cell biological research was revolutionized by the so-called patch-clamp method developed by Sakmann and Neher in 1981. The patch-clamp technique allows the direct measurement of currents generated by the ion transporters in the membrane with high temporal resolution. The resulting advantages are known. For example, it is possible to determine directly the effect of signal molecules or pharmacologically active substances on a target protein. In addition, the patch-clamp technique allows precise control of the electrical and chemical environment of a membrane and also allows the application of signal molecules, pharmacologically active substances, etc. to both sides of a membrane. In view of the fact that the patch-clamp technique is known in the art and is widely used, it should be dispensed with further basic embodiments.

The usual procedure in the patch-clamp technique is to mechanically approximate a glass capillary or glass (micro-) pipette of a cell and thus of its cell membrane and to fix it there by suction. This leads to an electrically dense connection between the cell membrane and the tip of the pipette. This electrically sealed connection is a prerequisite for a high-resolution, low-noise measurement of small and very small currents. The electrically sealed connection is often referred to as a "seal." In order to make reasonable patch clamp measurements, a so-called "gigaseal" is required; H. an electrically sealed connection in which the electrical resistance reaches the gigaohm range. Typically, resistors of 10 G ohms and above are needed to assure that even small ions such as protons do not pass uncontrollably between cell membrane and glass surface.

The described patch-clamp technique with contacting the glass pipette to the cell membrane "from outside" has been modified in the past with advantage by introducing the cell or corresponding biological structure into the interior of a glass capillary or glass (micro) pipette With regard to the exact procedure, reference is made to WO 02/10747 A2 for this purpose The advantages thus achieved can also be taken from this publication.

The glass pipettes or glass capillaries used for prior art patch clamp experiments typically have a cone-shaped tip and a portion adjacent to this tip that is substantially tube-shaped. Such pipettes or capillaries are generally produced by conventional glass blowing technology. by drawing (pulling) glass tubes after or at melting of the area where the conical constriction and tip is to be created. Such pipettes or capillary tubes with conical tip are then used both for those techniques in which the glass capillary is introduced from the outside to the cell membrane, and in those techniques in which the cell is fixed inside the capillary to form a gigaseal.

In the latter techniques (fixation of the cell in the interior of the capillary), it may then be difficult if in the interior of the capillary, in particular faster, replacement of the solutions contained therein is required. As mentioned, the interaction of the membrane proteins and / or the interior of the cell with agents or drug candidates brought to the outside of the membrane is frequently to be investigated in patch-clamp experiments. This bringing the corresponding substances to the membrane should always be as fast as possible. In the case of chemically controlled processes on the membrane, this is often even mandatory.

Due to their shape and geometry, the previously known pipettes and capillaries are not optimal for such a rapid change of solution or for a rapid bringing of active ingredients or drug candidates to the cell membrane. With the patch-clamp techniques, in which the cell is fixed inside the capillary, one wanted to provide, at least at the place of the fixation, a narrowest possible form of the capillary or the cone.

Although it is known from the publication of Miriam B. Goodman and Shawn R. Lockery (Journal of Neuroscience Methods 100 (2000), pages 13 to 15) to edit the tips of pipettes by so-called "pressure polishing." There is the tip a usual capillary or pipette with the help of a gas pressure. For this purpose, a V-shaped filament, which acts as a punctiform heat source, directed with its tip on the tip of the glass pipette. Due to the generated substantially spherical heat radiation field only the immediate tip of the pipette is melted and expanded. The thus obtained extended section on the cone of the pipette thereby reaches a maximum diameter of about 30 to 35 μm and is therefore unsuitable for use in techniques which fix the cell inside the capillary / pipette. Accordingly, the cited publication also deals exclusively with the usual patch-clamp techniques, in which the glass capillary is brought from the outside to the membrane of a cell.

Accordingly, the object of the invention is to provide a new method by means of which glass pipettes or glass capillaries can be produced. In particular, this should make new pipettes or capillaries accessible, which can be advantageously used in the case of patch pipettes.

Clamp techniques can be used in which the cell or corresponding biological structure is fixed inside the capillary to form a Gigaseals.

It is another object of the invention to develop a device for providing such pipettes or capillaries, in particular a device for carrying out the new method.

This object is achieved by the method with the features of claim 1 and by the device according to the features of claim 10. Preferred embodiments of the method and apparatus according to the invention are defined in the dependent claims 2 to 9 and 11 to 20. The wording of all claims is hereby incorporated by reference into the content of this description. The process according to the invention for producing glass pipettes or glass capillaries, which are intended in particular for patch clamp experiments, comprises the following process steps:

First, a glass pipette or glass capillary having a cone-shaped tip and a substantially tubular portion adjoining the tip is fixed in a holding device. The fixed glass pipette is placed in the heat radiation field of a heater. This is preferably done so that the fixed glass pipette is moved by means of a positioning in the heat radiation field of the heater. The glass pipette is softened, in particular melted, at least in the region of the tip, in particular in the region of the base surface of the cone, and optionally also in the part of the tube-shaped section adjoining the tip. This softening is preferably carried out in sections. Before softening and / or in the softened state, the interior of the glass pipette and thus also its softened area is subjected to a gas pressure. This results in that the

Diameter of the pipette between the base surface of the cone and the tubular portion of the glass pipette jumped expanded to a larger diameter than at the base surface. Jump-shaped should mean here that the enlargement / enlargement of the diameter takes place over a short length, in particular over a length of less than 150 μm. Preferably, the diameter, in particular from a value of less than 50 μm at the base surface, should be extended to a diameter of at least 100 μm in the tubular section of the glass pipette.

The thus expanded glass pipette is removed from the heat radiation field of the heater again, preferably the Glass pipette is moved with the help of the positioning of the heat radiation field.

Finally, the method according to the invention is designed in such a way that the sudden enlargement of the diameter of the glass pipette is controlled and preferably also controlled by means of an optical observation device.

For explanation, the following is noted.

A cone is known to be a structure that has the shape of a cone or truncated cone. Accordingly, in the invention, the pipette / capillary has a tip with the shape of such a cone. Due to its production process (usually pulling / pulling from a capillary), this tip is not geometrically exactly conical in shape, but can essentially be described by such a cone shape. Since the tip is necessarily open, d. H. is not closed, it will be in the case of the invention is usually a cone in the form of a truncated cone.

A truncated cone is a body of revolution that results from cutting a smaller cone from a straight circular cone parallel to the base surface. In this way, two parallel circular surfaces, of which one designates the larger as the base surface and the smaller than the top surface. If this is again transferred to the case of the present invention, the cone of the tip with its (larger) base surface adjoins the tubular portion at the pipette / capillary.

The claimed method of the invention has the advantage that compared to the prior art, a much more pronounced, jump-shaped widening of the diameter of the capillary / pipette can be achieved, starting from the point at which the cell at is fixed to the corresponding patch clamp measurements inside the capillary / pipette, towards the tubular portion of the larger diameter capillary / pipette. This is done according to the invention in that a larger part of the pipette, preferably by section-wise melting and widening successively, in diameter is increased. In particular, by the sectional procedure, the desired expanded contour of the pipette can be achieved over a length which is greater than the extent of the heat radiation field. In addition, the measure according to the invention, preferably to provide a radial heat radiation field, also contributes to the success of the method according to the invention.

The process procedure described has the further advantage that the diameter enlargement desired for the glass pipettes and glass capillaries can be observed in a defined manner under optical control and optionally controlled. This means that pipettes or capillaries, which do not have the desired jump-shaped diameter increase, need not be checked and sorted out only with a complex control of already manufactured pipettes / capillaries, but that this control can be made specifically during the manufacturing process itself. In this way, it is not only possible to sort out incorrectly produced pipettes or capillaries during production. It is also possible to adjust the shape of the pipettes and capillaries in a targeted manner and to modify them according to the respective specifications. This allows a highly automated manufacturing, which goes far beyond what was previously possible in the production of pipettes or capillaries, especially those for patch-clamp experiments. The advantages mentioned and other advantages will be explained in more detail below.

In the method according to the invention, it is preferred if the glass pipette or glass capillary to be processed directly from a device for pulling such glass pipettes is transferred to the holding device. In this way it is ensured that freshly drawn (freshly gepullte) capillaries (further) are processed by the method according to the invention. Under certain circumstances, it is also advantageously possible to use the same holding device for pulling the glass pipettes, which is also used to fix the pipette for the method according to the invention.

As already explained, in the method according to the invention the fixed glass pipette is introduced into the heat radiation field of a heating device. The advantageous embodiment of the heater will be explained later in connection with the device according to the invention. These statements are expressly incorporated and referenced.

In this context, it is of course possible to move the heater relative to the fixed glass pipette. However, since the softening process in the heater in the invention is preferably optically observed, it is preferable not to move the heater relative to the glass pipette but the glass pipette with the holding device relative to the heater. This is preferably done with the aid of a positioning device which is either already part of the holding device or cooperates with this holding device. In this context, it is of course possible to move the fixed glass pipette when introduced into the heat radiation field of the heater in all three spatial directions (x, y, z direction). In many cases, however, it is simpler to pre-fix the heating device and the holding device in two spatial directions (eg y- and z-direction) relative to one another, so that the holding device is introduced by means of the positioning device for introducing the fixed glass pipette into the heat radiation field only in one spatial direction (eg x-direction) must be moved. In these cases, the glass pipette is usually set in the holding device such that the movement in the x-direction corresponds to a movement in the axial direction (longitudinal direction) of the glass pipette. The movement in the x-direction is expedient anyway and usually provided, as with this movement (smöglichkeit) and the introduction and removal (replacement) of the pipette is accomplished in the holding device.

Of course, the abovementioned embodiments also apply accordingly to the removal of the expanded glass pipette from the heat radiation field of the heating device. In this case, it is of course preferred for simplification of the control, when the glass pipette is moved back after the expansion substantially in the starting position in which it was located prior to introduction into the heat radiation field. There, the glass pipette can cool down. In order to reliably rule out that the pipette still changes its shape during a gradual cooling, the cooling can be accelerated, preferably by blowing with air, for example through a cooling valve.

As explained, the interior of the glass pipette is subjected to a gas pressure, so that the desired extension of the diameter of the pipette occurs. It is basically preferred if the interior of the pipette is subjected to a continuous (constant) gas pressure. For this purpose, for example, a proportional valve may be provided. This pressurization can take place before and / or during the softening / melting of the glass pipette. However, it is also possible to work with pressure pulses, wherein both the duration of the pressure pulses and the pauses between individual pressure pulses can be varied. It is also possible to change the pressure values of individual pressure pulses. With all these measures, a more targeted procedure is possible. As a rule, the pressures in the invention are between 0.1 and 10 bar (10 to 1,000 KPa). Prints in the Order of 1 bar (100 KPa) are preferred. Usually, air is used as the gas.

As already explained, the jump-like widening of the diameter of the glass pipette (and possibly also the softening and melting process) is controlled by means of an optical observation device. For this purpose, a wide variety of parameters of the optically imaged shape of the pipette can be selected. In principle, such an entire contour line of a glass pipette can be observed during the process. In simplified embodiments, the (foremost) tip of the cone is not necessarily chosen as the starting point or point of origin for these measurements. At (fixed) distance from this "zero position", at least one diameter of the glass pipette can be followed before, during or after the expansion of the pipette with the gas pressure In this connection, it has been proven to have three fixed distance diameters from the foremost tip of the It has also been found to be advantageous in the case of the length of the tip between the base surface and the top surface of the cone to be determined before, during and after the expansion, the location of the top surface of the cone being in accordance with the location of the foremost one Preferably, the value of the length of the tip together with at least one diameter at a distance from the foremost point, preferably with the three diameter values, is determined in this way Control of the geometry of the expanded pipette available.

For the sake of order, it should be noted that the overall method in the case of the described preferred method procedure is essentially determined by three method parameters, namely

Temperature of the heat radiation field acting on the fixed glass pipette. x position of the fixed glass pipette, and gas pressure for diameter expansion.

In addition to the method according to the invention, the invention also encompasses a device for the production of glass pipettes or glass capillaries, which are provided in particular for patch clamp experiments, with the following devices: a holding device for fixing the glass pipette. a heating device for softening, in particular melting, regions of the glass pipette with the aid of a heat radiation field. a positioning device for controlled movement and positioning of the glass pipette at least in its axial direction with respect to the heating device. Preferably, the holding device is moved by means of this positioning device. a device for defined loading of the interior of the glass pipette with a gas pressure. an observation device for optically observing the glass pipette, in particular the region of the tip of the Glaspipet- te, during the heating and during the application of the

Glass pipette with gas pressure. a control / control device for selecting and influencing the parameters of the method carried out with the device, in particular for influencing the temperature in the heating device, the gas pressure and the movement (in particular in the axial direction of the pipette) of the positioning device.

In order to explain the function of the individual devices of the device according to the invention, reference is made both to the following embodiments as well as to the statements already made on the method according to the invention and expressly referred to. The explanations of the process according to the invention are intended to expressly be part of the explanation of the device according to the invention and vice versa.

In preferred embodiments of the device according to the invention, the holding device is a clamping device for the pipette or capillary. In this way, the pipette can be fixed in a simple manner in the holding device and remove it again.

In order to avoid pressure losses during the expansion of the pipette and to improve the controllability of the process control, the glass pipette in the invention is preferably in the holding device pressure-tight fixable.

In principle, any suitable heating device for generating heat radiation (IR radiation) can be used to generate a heat radiation field. This may be, for example, a gas flame (eg acetylene flame) or an infrared laser. However, it is preferred if the heating device is a so-called heating filament. Such heating filaments are known to the person skilled in the art.

In a further development of the invention, the heating device, in particular the Heizfilament, substantially annular or U-shaped forms, so that it accordingly surrounds the glass pipette at least partially on its outer circumference. Such enclosing the glass pipette to produce a radially homogeneous heat radiation field can be produced in a simple manner with such U-shaped heaters or heating filaments.

Since the pipette in particular during the softening of the glass in the heat radiation field, in particular during partial melting, and is to be observed in the expansion by gas pressure, it is advantageous if the heater allows a clear view of the optical detection on the pipette. This can be achieved in particular in that the heating device or the Heizfilament is tilted against the longitudinal direction of the glass pipette. This is preferably done at an angle of about 45 °.

In a further development, the heating device is designed such that its heating power is current-controlled. This allows a particularly simple change of the heat radiation field when softening the glass pipette.

In the device according to the invention, the device for defined loading of the interior of the glass pipette is formed with a gas pressure, preferably for continuous pressurization. Preferably, this has a proportional valve for controllable continuous pressurization. The associated advantages have already been explained in connection with the method according to the invention.

For optical observation of the glass pipette during melting and pressurization with gas pressure basically all possible optical observation devices can be used, for example, those with CCD or CMOS technology. Preferably, an observation device is used in the invention, which can be described as a measuring microscope with CCD camera. So it is a magnifying lens, for example, with 10x magnification, used, which is combined with a CCD camera. This camera can be designed as a grayscale camera. This observation device is focused on the tip of the pipette, wherein expediently an automatic focusing device is provided. The control / monitoring device in the device according to the invention preferably comprises an image processing system, with the help of which the change of the .Oußenkontur the pipette can be followed during the heating and during the pressurization. A recording of the corresponding image sequence can also be provided.

Finally, the device according to the invention may also comprise a device for drawing glass pipettes or glass capillaries. In this way it is possible to introduce freshly drawn pipettes or capillaries directly into the device according to the invention.

Further features of the invention will become apparent from the following description of preferred embodiments in conjunction with the subclaims. In this case, the individual features can be implemented individually or in combination with one another in each case. The described embodiments are merely illustrative and for a better understanding of the invention and are in no way limiting.

In the drawings show:

1 is a schematic diagram for explaining the method and apparatus of the invention, and

2 shows a pipette or capillary which can be produced with the method according to the invention and the device according to the invention in a schematic representation. The schematic diagram of FIG. 1 shows, on the one hand, some essential components of the device according to the invention and, on the other hand, a rough course of the method according to the invention.

Thus, in Fig. 1, a glass pipette or glass capillary 1 is shown, which is fixed in a holding device 2 (clamping device). The holding device 2 is provided with a positioning device (not shown), by means of which the capillary 1 fixed in the holding device 2 in the x direction, i. H. in the axial direction of the capillary 1 is movable.

Furthermore, FIG. 1 shows a heating device 3 in the form of a U-shaped heating filament which can generate a radially homogeneous heat radiation field for softening or melting the capillary 1. Next, an observation device 4 is provided in Fig. 1, which consists of a lamp 5, a microscope lens 6 and a CCD camera 7. With the aid of this movable observation device 4, the pipette 1 is observable during the softening / melting process and during the pressurization of the pipette with gas pressure. To ensure this, the heating filament is tilted by approx. 45 ° to the direction of observation.

Further details of a device according to the invention are not shown in FIG. 1, in particular not the device for defined loading of the interior of the glass pipette with a gas pressure and possibly existing control and monitoring devices.

The sequence of the method according to the invention is also indicated schematically in FIG. 1, wherein the shape and approximate position of the capillary 1 in the process stages I ₁ II, III and IV is shown.

Thus, the capillary 1 fixed in the holding device 2 in the process stage I in the heat radiation field of the heater 3 in x-rich tion, so that the (first) dilated Kapillarabschnitt comes to rest in the heat radiation field. Preferably, this first section is that in the process control, which (with respect to the capillary) farthest from the top of the capillary.

As soon as the (first) section of the capillary to be expanded is in the heat radiation field, the inside of the capillary is exposed to a constant gas pressure of approx. 1 bar. In principle, it is also possible to introduce a capillary which has already been subjected to the gas pressure into the heat radiation field.

As shown schematically in process stage II in FIG. 1, the softened / melted first capillary section is widened by the gas pressure. As soon as this has been done (to the desired extent) under the optical control provided according to the invention, the next (second) capillary section is moved into the heat radiation field by appropriate movement of the capillary in the x-direction. This next (second) capillary section is closer to the top of the capillary than the first, already expanded capillary section. As soon as the glass of the capillary is also softened or melted at the second capillary section, a corresponding widening takes place here as well, due to the continuously existing gas pressure, which is likewise optically controlled again. This is shown schematically in process stage III in FIG. 1.

In the present case, the procedure according to the invention is such that the gas pressure is kept constant throughout the process. In this case, in the selected procedure, in which the sections of the capillary are widened in the direction of the tip, the energy content of the heat radiation field can be varied (for example by controlling the current of the heating filament used). customary In this case, the closer the section is to the tip of the capillary, the lower the energy content / heating power used. This is because the wall thickness of the glass capillary usually decreases towards the tip. With the same result, one could also proceed in such a way that the energy content / heat output is kept constant during the entire process duration and the gas pressure is reduced correspondingly the closer one gets to the tip of the capillary.

In method stage IV, a fourth and last method step is shown in FIG. 1, in which the region of the tip of the capillary itself is widened. For this purpose, that capillary section which is closest to the tip or comprises this tip is introduced into the heat radiation field by movement in the x direction and is widened by the constant gas pressure still applied. In this way, then the final characteristic shape of the pipette / capillary with the sudden expansion of the diameter of the base surface of the remaining cone-shaped tip towards the substantially tubular portion of the pipette / capillary.

Finally, what is not shown in Fig. 1, the widened in the desired manner pipette in the x-direction completely moved out of the heat radiation field, or this heat radiation field is switched off. Then, a gradual cooling of the final molded pipette is usually done in air. This cooling can be additionally accelerated by blowing the cold air pipette by means not shown.

FIG. 2 shows the shape and dimensions of an exemplified glass pipette or glass capillary, as used with the invention

Method and the device according to the invention can be obtained. Characteristic is the sudden widening of the diameter diameter of the capillary between the region of the cone-shaped tip and the adjoining this tip substantially tubular portion of the capillary.

As also described in the description, FIG. 2 also shows four values as determined for controlling and controlling the sudden enlargement of the diameter in the production of such pipettes or capillaries in the method according to the invention. As described, the original position (zero position) is selected at the (foremost) tip of the cone. The four values that are determined are then the length of the peak between zero position / original position (on the top surface of the cone) and the base surface of the cone. Furthermore, the diameter values in the tubular section are determined at three (predetermined) points.

In the present case, the length of the tip 31, 4 microns. The three diameter values in the tubular section are 138.9 μm, 169.0 μm and 189.0 μm. It goes without saying that these are merely exemplary values which in no way limit the subject matter of the present invention.

Claims

claims

1. A process for the production of glass pipettes or glass capillaries, in particular for patch clamp experiments, in which at least one glass pipette or glass capillary (1) having a conical tip and a substantially tubular portion adjoining the tip, in a holding device ( 2) is fixed, the fixed glass pipette (1) is introduced into the heat radiation field of a heater (3), wherein preferably the fixed glass pipette is moved by means of a positioning in the heat radiation field of the heater, the glass pipette at least in the region of the tip, in particular in the area the base surface of the cone, and optionally also softened in the adjoining the tip part of the tubular portion, is preferably melted, wherein the softening is preferably carried out in sections. the interior of the glass pipette (1) is subjected to a gas pressure before softening and / or in the softened state, such that the diameter of the pipette between the base surface of the cone and the tubular portion of the glass pipette jump, ie over a small length to a gas pressure larger diameter than at the base surface, in particular to a diameter of at least 100 microns, extended, the thus expanded glass pipette (1) from the heat radiation field of the heater (3) is removed, wherein preferably the glass pipette with the aid of the positioning device is moved out of the heat radiation field . the jump-shaped extension of the diameter of the glass pipette (1) by means of an optical observation device (4) is controlled and preferably controlled.

2. The method according to claim 1, characterized in that the glass pipette is transferred directly from a device for pulling such glass pipettes in the holding device.

3. The method according to claim 1 or 2, characterized in that the fixed glass pipette during insertion and removal from the heat radiation field substantially only axially, d. H. in the direction of its longitudinal direction, is moved by means of the positioning device.

4. The method according to any one of the preceding claims, characterized in that the glass pipette is moved back after softening in the heat radiation field substantially in the initial position in which it was located prior to introduction into the heat radiation field.

5. The method according to any one of the preceding claims, characterized in that a continuous gas pressure is built up in the interior of the glass pipette.

6. The method according to any one of the preceding claims, characterized in that different longitudinal sections of the glass pipette are successively introduced into the heat radiation field and there widened by application of gas pressure, wherein preferably the resulting flared contour of the glass pipette in the axial direction has a greater length than the extension the heat radiation field in this axial direction.

7. The method according to any one of the preceding claims, characterized in that the change in the outer contour of the glass pipette is observed to control and control the abrupt extension of the diameter, wherein preferably the change in dimensions of the glass pipette is determined at predefined locations.

8. The method according to claim 7, characterized in that at least one diameter of the glass pipette, preferably three diameters, are determined at a fixed distance from the tip of the glass pipette.

9. The method according to claim 7 or claim 8, characterized in that the length of the tip between the base surface and the top surface of the cone is determined.

10. Apparatus for the production of glass pipettes or glass capillaries (1), in particular for patch clamp experiments, with a holding device (2) for fixing the glass pipette (1), a heating device (3) for softening, in particular melting, of areas of Glass pipette with the aid of a heat radiation field, a positioning device for the controlled movement and positioning of the glass pipette at least in its axial direction with respect to the heating device, wherein preferably the holding device is movable with the aid of this positioning device, a device for defined pressurization of the interior of the glass pipette with a gas pressure, an observation device (4) for optically observing the glass pipette, in particular the region of the tip the glass pipette, during the heating and loading of the glass pipette with gas pressure, and a control / Konto !, means for selecting and influencing the parameters of the method carried out with the device, in particular for influencing the temperature in the heater, the gas pressure and the movement of the positioning.

11. The device according to claim 10, characterized in that it is at the Halteeinrichung (2) is a clamping device.

12. The device according to claim 10 or claim 11, characterized in that the glass pipette is pressure-tight fixable in the holding device.

13. Device according to one of claims 10 to 12, characterized in that it is a so-called Heizfilament in the heating device (3).

14. Device according to one of claims 10 to 13, characterized in that the heating device (3), in particular the Heizfilament, U-shaped and accordingly surrounds the glass pipette at its outer periphery at least partially.

15. Device according to one of claims 10 to 14, characterized in that the heating device (3), in particular the Heizfilament, is inclined against the longitudinal direction of the glass pipette, preferably at an angle of about 45 °.

16. Device according to one of claims 10 to 15, characterized in that the heating power of the heating device is current-controlled.

17. Device according to one of claims 10 to 16, characterized in that the means for defined loading of the interior of the glass pipette is formed with a constant gas pressure.

18. Device according to one of claims 10 to 17, characterized in that it is in the observation device to a measuring microscope (6) with CCD camera (7).

19. Device according to one of claims 10 to 18, characterized in that the control / Kontrollinhchtung comprises an image processing system by means of which the change in the outer contour of the glass pipette can be traced during the heating and during the pressurization.

20. Device according to one of claims 10 to 19, further characterized by a device for pulling glass pipettes o- or glass capillaries.