GB2386571A

GB2386571A - Pipette with finger pressure application means proximate the tip of the device, and method of usage

Info

Publication number: GB2386571A
Application number: GB0206909A
Authority: GB
Inventors: Farhang Abed
Original assignee: FERTILITY MEDICAL EQUIPMENT LT
Current assignee: FERTILITY MEDICAL EQUIPMENT LT
Priority date: 2002-03-23
Filing date: 2002-03-23
Publication date: 2003-09-24
Also published as: GB0206909D0

Abstract

A pipette comprises an elongate hollow body 10 and deformable finger pressure application means, such as a thinning in a wall of the body 10, or circumferential groove 22, proximate a material entry and exit aperture 18 at one end of the pipette. Also disclosed is a method of using the pipette by applying controlled finger pressure to the deformable means to encourage the imbibing of material into, or ejection of material from, the pipette using variation in air pressure in the standard manner of pipettes. When the deformable means is in form of a circumferential groove 22, the groove 22 may be covered by an elastic tube 26. The pipette may further feature a distal end cap 14, and variety of detachable tips 20 (20a, fig.4, 20b, fig.5).

Description

SUCTION APPARATUS AND METHODS

This invention relates generally to apparatus for and methods of transferring material by suction, and is particularly concerned with the transfer of biological 5 material in a variety of media and solutions. More particularly, the invention is concerned with effecting the transfer of embryos and oocytes in various procedures involved in assisted reproductive technology (ART).

The transfer of embryos and oocytes through various 10 media and solutions is one of the most important steps in assisted reproductive technologyprocedures. For example, transfer is necessary: À during follicular aspiration; À after fertilization, for removal of the corona to assess 15 the presence of pronuclei in conventional in vitro fertilization (IVF); À in the stripping of cumulus and corona cells from oocytes prior to intra cytoplasmic sperm insertion (ICSI);

20 À during the freezing and thawing of embryos; À during transfer of embryos to the uterus; À during stem cell research and in cloning procedures.

Currently, for some of these purposes, embryologists involved in assisted reproductive technology use a fire 25 polished pasture pipette. In this type of pipette, a long plastics tube is used, with one end of the tube connected to the top of the pipette and the other end arranged to be held in the mouth. Suction is applied by the user, and as a result of this embryos and oocytes can be drawn into the 30 pipette or expelled from the pipette. Using this technique,

red: embryos and oocytes can be transferred, using various media and solutions. However, this conventional method has some disadvantages, including the possibility of contamination of samples from the mouth of the embryologist or vice versa.

5 Additionally, it is technically difficult to make a heat-

treated narrow pipette having precise dimensions. Moreover, the exhalation of carbon dioxide by the embryologist may change the pH of the fluid medium, thereby giving rise to further potential problems.

10 The apparatus and methods of the present invention find particular use in the procedures listed above and which are carried out in assisted reproductive technology. However, the apparatus and methods of the invention are not to be regarded as limited to these procedures. The invention is 15 not even limited to the transfer of biological material.

Broadly in accordance with the invention there is provided a method of transferring material, which comprises using finger pressure to deform the shape of an elongate, hollow pipette adjacent to the active end thereof and thereby 20 to expel a volume of air therefrom, inserting an open tip of the pipette into a medium or solution containing the material to be transferred, and reducing the finger pressure to reduce the deformation and thereby draw the material into the pipette. 25 Preferably, the material is subsequently expelled from the pipette by repeating the finger pressure deformation of the pipette.

Also in accordance with the invention there is provided apparatus for the transfer of material! comprising an 30 elongate, hollow pipette having an aperture at one end for

the entry and exit of such material, and means adjacent to the aperture deformable by the application of finger pressure to a surface of the pipette to expel or draw in a volume of air through said aperture, thereby to create a fluid flow in 5 or out through said aperture controlled by finger pressure.

Preferably, a portion of the wall of the pipette which is apertured is overlaid with a resilient material which can be depressed but which will return to a cylindrical configuration when finger pressure is removed. The resilient 10 material can be in the form of a collar recessed into al circumferential groove in the body of the pipette. The groove is preferably provided with two apertures, on opposite sides of the pipette.

Thus, one can generate a suction/expulsion effect at the 15 tip. Various shapes of apertured tip can be used, depending upon the transfer technique involved.

In order that the invention may be more fully understood, a description will now be given of one embodiment

of pipette in accordance with the invention and which is 20 illustrated in the accompanying drawing, by way of example.

In the drawing: Fig. 1 is a longitudinal sectional view through the body of the pipette, omitting the tip; Fig. 2 is a longitudinal sectional view through the body 25 of the pipette, rotated through 90 from Fig. 1, and omitting the resilient collar and end cap; Fig. 3 is an external view of the pipette, with the tip in place; Fig. 4 shows a first alternative form of tip; and 30 Fig. 5 shows a second alternative form of tip.

I The apparatus of the present invention, which functions generally in the manner of a pipette, comprises a body portion 10 which is of elongate, generally cylindrical form.

One end of the body portion 10 is open, as indicated at 12.

5 This open end 12 can be closed by the fitting of a cap 14.

This both prevents leakage of liquids from the pipette and also seals that end of the pipette against the passage of air into or from the pipette through that end. At the end remote from the cap end 12, the body portion 10 narrows in a 10 tapering manner to form a reduced cross- section nozzle 16 which has an end aperture 18. The nozzle end 16 of the body portion is fitted with a tip 20, as shown in Fig. 3.

Preferably, the retention of the tip 20 on the nozzle end 16 is aided by the provision of a male/female coupling between 15 the two parts. For example, the tip 20 can be provided with a female hub which cooperates with a male fitting on the nozzle end 16. Other types of retention mechanism can be used to ensure that the tip 20 is held in place on the nozzle end. 20 Three different types of tip are shown in the drawings.

The tip 20 which is shown in Fig. 3 is a short, relatively small diameter tip which can be used for removing the corona cells from oocytes to assess the presence of pronuclei in conventional IVF procedures, or alternatively to strip 25 cumulus and corona cells from oocytes prior to ICSI.

The alternative tip 20a shown in Fig. 4 is a short, somewhat wider diameter tip which can be used for the transfer of oocytes during follicular aspiration or for the transfer of embryos during freezing or thawing procedures.

30 The tip 20b shown in Fig. 5 is a long, flexible tip

which can be used for example for the transfer of embryos to the uterus. In each case the tip 20, 20a, 20b is preferably made of plastics material. The body portion 10 can also be made of plastics material, for example by an injection 5 moulding technique. The cap 14 can also be made of plastics material by an injection moulding technique.

Towards the end of the body portion 10 which has the nozzle end 16, the body portion is provided with a circumferential groove 22, so that the wall of the body 10 portion is here of reduced thickness. At two opposed positions around the circumference of the grooved zone, the wall of the body portion is apertured, as indicated at 24 in Fig. 2. An elastic tube 26 of rubber or like material is provided to cover the grooved portion 22 of the pipette, 15 including the apertures 24. The cover 26 is cylindrical and has a thickness which is matched to the depth of the groove 22 so that the pipette has a smoothly continuous external surface. The method of using the pipette of the present invention 20 will now be described. Firstly, a tip 20, 20a, 20b appropriate to the particular application which is involved is chosen and is fitted to the nozzle end 16 of the pipette.

The pipette is used in the manner of a pen, such as is used for writing. It is held in the fingers by the user, with the 25 tip being analogous to the writing tip of the pen. By gently pressing on the cover 26 above one or both of the apertures 24, a small amount of air will be expelled from the pipette through the end aperture 18. The pressure within the pipette will then be slightly less than the atmospheric pressure of 30 the ambient surroundings. If the tip 20, 20a, 20b is then

- ' - inserted into the medium or solution being used for the procedure, and if the finger pressure on the cover 26 is reduced, then the relevant material will be drawn into the tip through the aperture 18 together with the medium or 5 solution in which it exists. Subsequently, the material and the accompanying medium or solution can be expelled from the pipette simply by again depressing the cover 26 in the region of the apertures 24.

The pipette can be for single-use only, i.e. be 10 disposable, or can be intended for repeated use, in which case one would replace the tip for each single use.

The pipette according to the invention has the particular advantage that it is simple to use and enables an embryologist for example to have full control of the pipette 15 during its application. This is because the movement of the pipette and the movement of the material into and out of the tip is effected using one hand only. Also, the fact that single finger pressure or the pressure of two fingers is all that is needed in order to cause the movement of the material 20 into and out of the tip means that the transfer procedure can be controlled very accurately and effectively.

Although two opposed apertures 24 are shown in this embodiment, other alternatives could be used, for example the provision of just a single aperture or window.

Claims

1. A method of transferring material, which comprises using finger pressure to deform the shape of an elongate, hollow pipette adjacent to the active end thereof and thereby 5 to expel a volume of air therefrom, inserting an open tip of the pipette into a medium or solution containing material to be transferred, and reducing the finger pressure to reduce the deformation and thereby draw the material into the pipette. 10

2. Apparatus for the transfer of material using suction, comprising an elongate, hollow pipette having an aperture at one end for the entry and exit of such material, and means adjacent to the aperture deformable "by the application of finger pressure to a surface of the pipette to 15 expel or draw in a volume of air through said end aperture, thereby to create a fluid flow in or out through said aperture controlled by finger pressure.

3. Apparatus according to claim 2, in which a portion of the wall of the pipette which is apertured is overlaid 20 with a resilient material which can be depressed but which will return to a cylindrical configuration when finger pressure is removed.

4. Apparatus according to claim 3, in which the resilient material comprises a collar recessed into a 25 circumferential groove in the body of the pipette.

5. Apparatus according to claim 4, in which the groove is provided with two apertures, on opposite sides of the pipette.

6. Apparatus according to any of claims 2 to 5, in 30 which the pipette has a removable tip.