DE29610622U1 - Water bath shaker to carry out chemical or biochemical tests - Google Patents

Description

medipro 17 June 1996

Medical Diagnostic Products GmbH M 21780 GM2 Ds/hi

Water bath shaker for carrying out chemical or biochemical tests

The invention relates to a water bath shaker according to the preamble of claim 1.

The water bath shaker according to the invention enables in particular the performance of immunochemical, genetic engineering, molecular biological, chemical or biochemical investigations, whereby the samples are kept at a certain temperature by means of a regulated hybridization incubation shaking water bath.

Shaking water baths are known for carrying out chemical and biochemical reactions, hybridizations, fermentations, etc., in which the water temperature is regulated to adjustable values. The samples are placed in the water bath using racks for test tubes or trays with clamps for flasks and bottles, which is kept at a uniform temperature by the shaking movements and a control device. If maintaining a certain temperature is particularly critical, the temperature is controlled electronically.

Known devices of this type have the disadvantage that only one temperature can be set in the bath. If several

If reactions are to be carried out at different temperatures simultaneously, this requires several shaking water baths and thus a considerable amount of effort and space, since such a water bath takes up an area of about 1/3 m ² .

An example of the simultaneous execution of several reactions is a diagnostic detection method in which amplified DNA or RNA material is hybridized to/on nitrocellulose membrane strips labeled oligonucleotides (so-called reverse dot blot technique). This requires very precise, constant reaction temperatures of, for example, 42°, 45°, 47°, 55°, 56° or 63 ^° C over a very specific period of time. The corresponding functional principle is shown in Figure 1.

Shaking water baths are already known from a brochure by the company Gesellschaft für Labortechnik mbH (GFL Swb 1292,32d) "Shaking water baths, shaking incubators for shaking and temperature control with high consistency".

These known shaking baths do not meet the requirements of today's general engineering, immunochemical or molecular biological detection methods. The required temperature-controlled reaction processes for hybridization or incubation can only be set by a single heating source with only one single temperature for the entire oversized water container. Reaction vessels in immunochemical detection methods or in molecular biology and genetic engineering, e.g. microtiter plates or incubation trays, cannot be fixed in the designated water container or kept at a specific water immersion depth.

Shaking baths and related equipment are also known from the following publications:

WO 90 05 023 A1;

EP 06 42 831 Al; EN 29 25 471 Al; EN 38 08 942 Al; EN 92 00 929 Ul; US 50 52 812; DE-OS 21 20 435; US 42 64 559; EP 03 39 710 A2; EN 84 21 314 Ul; EN 39 41 168 Al; DE-OS 19 00 279; EN 25 04 269 C2 EN 34 41 179 Al; US 49 67 061; Brochure. Robotherm, Edmund Bühler, 1992; and Precision shaker • Baths. In: Biotechnology Laboratory; Feb. 1992.

Furthermore, it is known from ROBBINS SCIENTIFIC, USA, brochure 5M/495, to arrange two times two flat water trays on a shaking table. Each water tray can be independently tempered. This shaking water bath does not meet the requirements of today's usual genetic engineering, immunochemical or molecular biological detection methods, since the water evaporates at the required temperatures and the vapor water falls into the reaction vessels. Furthermore, increased humidity occurs in the small air space above the water surface, so that there is an increased risk of contamination and thus increased cross-reactivity.

The invention is based on the object of providing a water bath shaker for carrying out chemical or biochemical investigations of the initially

type, which is suitable for the simultaneous execution of different tests even over comparatively long periods of time.

This object is achieved according to the invention by a water bath shaker which is defined in the claims.

The invention is associated with a number of advantages.

On the one hand, the individual assignment of one heating device to exactly one water tank enables several tests or laboratory procedures to be carried out simultaneously at different temperatures and with the highest level of accuracy; the number of tests that can be carried out simultaneously is equal to the number of water tanks.

is On the other hand, the design of the sample carrier ensures that samples arranged in the sample carriers are kept below or above the water level of the respective water container during the entire incubation period, even if the height of the water level changes, for example, due to evaporation of water. In this way, the water bath shaker according to the invention ensures that even comparatively long incubation times can be carried out without the positioning of the sample carriers having to be monitored and, if necessary, corrected by manual intervention. With the water bath shaker according to the invention, neither personnel expenditure for such monitoring nor personnel expenditure for manual correction is required. In addition, the water bath shaker according to the invention, in which manual interventions that can lead to temperature changes in the samples, also enables incubations to be carried out that require a very high temperature consistency of the samples.

The sample carrier is preferably measured in the upper half of the water container, e.g. at a height in the second quarter from the top, such that

arranged so that there is sufficient air space above it. This advantageously avoids excessive humidity and the resulting risk of mutual contamination of the samples during certain test procedures.

The water tanks are characterized by an advantageous ratio of surface area and space requirements. The numerical ratio of cross-sectional area in cm ² to the height of the water tank in cm can preferably be in the range of 15 to 25. An advantageous value for this ratio is approximately Ø 22. It is advisable to work with a water filling of approximately 3,240 cm ³ in each water tank in order to help maintain the control temperature. Typical dimensions of the water tanks are 18 cm x 18 cm x 15 cm (width, depth, height).

The water containers can have any cross-section, e.g. round or square. It is often practical to choose a rectangular cross-section. For example, the dimensions can be such that a so-called microtiter plate in lengthwise or horizontal format can be used as a sample carrier.

Each water tank is individually assigned a heating device, whereby the heating devices can be regulated to different temperatures. The heating devices are arranged in or on the water tanks. The heating devices can also be installed at the location of the water tanks in the shaking table or in the table on which the water tanks are arranged.

Each heating device or water tank is assigned its own probe to record the actual value for the electronic temperature control, which can be attached near the sample carrier. It can also be mounted directly on the sample carrier, e.g. on a tray.

-D-

Further properties and advantages of the subject matter of the invention emerge from the following description of embodiments, which are shown schematically in the drawing. In it:

Fig. 1 schematically shows the functional principle of reverse hybridization technique

DNA and RNA amplification using oligonucleotide probes according to the state of the art;

Fig. 2 schematically shows embodiments of the invention;

Fig. 3 shows the placement of the test strips in an enlarged view

in a grooved plate placed on a shelf;
Fig. 4, 5,

6, 7 and 8 show the arrangement of water containers in a

Ben water bath shaker;

Fig. 9 a lid for a water tank; and

Fig. 10 a tray with grooved plates.

As shown schematically in Fig. 1, amplificates are obtained by extraction and amplification using known methods. Specific oligonucleotides are fixed in bands or dots on nitrocellulose strips or membranes.

The applied amplificates react with the oligonucleotides specific to them at very precise and specific temperatures (hybridization). The oligo-allele-specific bonds are detected in a chromogenic reaction.

To carry out the reactions, according to the invention, the column-shaped water containers 1, 2, 3 shown in Fig. 2 are provided, which can be arranged on a shaking table 4 of known function. The

Shaking table can also accommodate more than three water containers (Fig. 4, 5). It will usually be equipped with a frequency control for the shaking frequency.

In the embodiment shown in Figures 4 and 5, four water containers are fixed to the surface of the shaking table 4 per device unit. The surface shakes continuously at a shaking frequency of 0-300 min" ¹ in back and forth movements. The shaking frequency is adjustable and is displayed digitally. The duration of the shaking frequency can be optionally

&iacgr;&ogr; time-limited in minutes 0 to 60 minutes or set to continuous operation .

Example technical data of the shaking table 4 are:

External dimensions: length 510 mm, width 510 mm, height 177 mm

Movement table: length 450 mm, width 450 mm

Load capacity: max. 15 kg

Movement type: back and forth

Shaking amplitude: 30 mm

Shaking frequency: 0-300 min" ¹

Instead of a shaking table 4, a shaking mechanism can also be provided. In this case, the water containers are not arranged on a shaking table 4, but on a table or in a block 27 (Figures 6 and 7), the surface of which can have the same dimensions as the shaking table. The shaking mechanism consists of a motor 29 (Figure 8), which applies the shaking movements to an arm 28. The arm 28 can be connected to the water containers or to sample carriers 11 in such a way that the shaking movements are transmitted to the sample carriers 11. The directions of the shaking movements are indicated by the arrows in Figure 7, with the directions indicated representing preferred directions: In addition to these movements or instead of these movements, transverse or eccentric or also (with respect to

e ·

the table surface) vertical movements are generated and transferred to the sample carriers. The arm with e.g. four crossbars, which serve to connect to a water container or the sample carrier, can be mechanically connected to the water containers or the sample carriers in different ways. This connection is in particular detachable. The design of the arm 28 is shown in Figures 6, 7 and 8. With this shaking mechanism, the sample carriers can be subjected to shaking movements in practically the same way as by means of the shaking table 4. The arrangement of the water containers (1, 2) in a block 27 with

Î a shaking mechanism (schematically shown drive unit 29 of the shaking mechanism) and the design of the arms 28, which can be angled downwards towards the sample carriers, as well as their connection to sample carriers 11 is shown in Figure 8. The sample carriers are height-adjustable (relative to the arm 28). In general, the

is water container or the sample carriers are connected to a shaking mechanism .

Each water container is filled with water of, for example, approximately 3,240 cm ³ . It has, for example, a circular, but in particular a rectangular cross-section of (18 cm x 18 cm =) 324 cm ² and a height of 15 cm. It consists, for example, of glass, plastic or metal, and in particular of rust-proof chrome-nickel steel sheet and has a water drain device 26 in its lower area. Known Erlenmeyer flasks can also be used as water containers for the water bath shaker according to the invention.

Each water tank 1, 2, 3 is individually assigned a heating device 5, 6 7. The heating devices are arranged in or on the assigned water tanks.

The heating devices 5, 6, 7 assigned individually to the water tanks can also be installed in the shaking table at the location of the water tanks 1, 2, 3

· t

4 (Figures 2 and 4) or in block 27 (Figures 6 and 7).

In addition to individually controllable heating devices, each of which is individually assigned to a water tank, heating devices can also be provided that are controlled to the same temperature value.

Figure 2 shows a schematic embodiment in which a heating device, e.g. an electric heating coil 5, 6, 7, is installed in the table 4 at each space provided for a water container.

To regulate the temperature of each individual water tank, there is a separate electronic control device (not shown) with a temperature adjustment knob 8, 9, 10 (Fig. 2, 4) for selecting different temperatures for the individual water tanks independently of one another.

For all four water tanks, for example, the following direct and independent temperature control is available: The temperature is controlled via microprocessors with an accuracy of ± 0.1 ⁰ C. The usable space temperature of the respective water tank is shown on a display 18 (Figure 4).

The temperature is set as follows: By pressing a water tank or heating device-specific temperature setting button 19 (Figure 4), the target value of the usable temperature in the respective water tank is shown on the corresponding water tank or heating device-specific display 18. By pressing the temperature setting button 19 and simultaneously turning the temperature setting knob 8, the desired usable space temperature for the respective water tank can be set. After releasing the temperature setting knob, the display 18 of the set water tank switches back to the current usable space temperature display. The respective heating period to reach the target temperature is indicated for each individual water tank by a water tank or heating device-specific signal lamp 20

· * ft *

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(Fig. 4). When the setpoint is set on the temperature setting knob, the temperature limit is automatically set to e.g. 2°C above the setpoint. If the temperature rises above the setpoint, the heating system switches off automatically. This fault is indicated by a signal lamp on the display 18.

The individual water containers 1, 2, 3 can be set independently to working space temperatures of 25-99 ⁰ C. A probe 17 serves as the actual value transmitter for this purpose. This probe is fixed under a tray ("sample carrier") U (Fig. 2, 3, 9, 10) or pedestal and is thus immersed in the water. The working space temperatures are controlled by microprocessors and kept constant (+ 0.1 ⁰ C).

As shown in Figure 2, a tray 11, e.g. made of stainless chrome-nickel steel, is inserted into each water tank on stands 12, which may be supported by

is held at the bottom by another tray 13. The trays 11, 13 are provided with a series of holes to allow the water to pass through. The length of the stands is chosen so that the water level reaches just above the tray 11 at a height of about the second quarter of the container, measured from the top, and flows around a grooved plate 14 from below, into the grooves 15 of which test strips or samples 16 are inserted.

For example, a stainless chrome-nickel steel sheet is fixed to four round pencil-thick chrome-nickel steel rods fixed to the floor, the height of which can be adjusted using rubber sleeves 21 (Fig. 9, 10), which forms the tray 11. The tray 11 as a carrier of the reaction vessels (e.g. microtiter plate fixed horizontally or vertically) is thus height-adjustable and adapts to the respective water level.

The shelf 11 is provided with 50 mm holes at a distance of 130 mm (Fig. 9, 10). On this plate provided with holes, two pairs of frame brackets 22 are provided at a distance of approx. 13 cm for

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to accommodate one plate (grooved, perforated or microtiter plate) in landscape or lengthwise format. The dimensions of a frame bracket are: length (from base to base of the angled legs) 8.8 cm, width B (of the part resting on the grooved plate with openings for screws) 1.3 cm, height 1.5 cm. The frame brackets are screwed to the tray 11 using screws 23 at a distance of 4.9 cm. The frame bracket pairs, which can be screwed or detachably attached in another way, enable grooved plates (microtiter plates) 14 to be arranged as desired on the tray 11. On the underside of the tray

A temperature probe 17 (platinum temperature sensor) is attached (Fig. 2, 3). However, this temperature probe can also be arranged, for example, at the bottom of the water container.

The shelf 11 is fixed to a bracket as already described.

The water level can be set at a height of 8-10 cm (with a height of the water tank of 15 cm). The air space above the shelf is 7-5 cm plus air space that can be formed by a cover 24 (Fig. 9).

The probes 17, in particular platinum temperature sensors, are provided as actual value transmitters for the electronic temperature control and can be attached to the underside of the tray or, for example, to the bottom of the water tank. Each water tank in operation is assigned its own actual value transmitter for signaling to the respective temperature controller.

Fig. 3 shows an enlarged view of the tray 11 on which the grooved plate 14 is arranged. It can be made of a plastic material or of metal and is conveniently clamped onto the tray using brackets or the frame bracket pairs 22. The water level reaches the underside of the grooved plate and holds the recesses/grooves 15 or the grooved plates 14 that can be removed.

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containers at a constant temperature. The test strips 16 are arranged in the grooves and should not come into contact with the water.

A probe 17 reports the temperature in the area surrounding the tray 11 to the associated control device for the heating. The probe can be attached to the wall of the water tank, in particular to the floor or, as shown, directly to the tray.

For the use of commercially available microtiter plates (= grooved plate 14) with

&iacgr;&ogr; e.g. a size of 12.8 cm &khgr; 8.6 cm it may be advantageous to

To form a water tank with a cross-sectional area and shape that is only slightly larger than such a plate.

As is known with shaking water baths, it is expedient to cover the device with an angled or saddle-shaped lid. A lid of this type for each water container can also be advantageous, as shown in Fig. 3 by 25. Preferably, as shown in Fig. 9, the water container is covered by an outer lid 24, which can be attached to the water container by means of a hinge. The lid 24 is angled in the middle, roof-shaped. It is designed in such a way that water evaporated from the water containers runs back into the water containers. In conjunction with the water containers described above, for example, it has a height of 7 cm.

The shaking water bath according to the invention can be manufactured in accordance with the regulations regarding quality seal testing and the medical device regulation regarding use in medical laboratories.

The invention can be used wherever shaking water baths of the known design have been used up to now, and offers advantages in the simultaneous execution of several tests and in the acceleration of longer test series without significantly increasing the equipment expenditure.

1 List of reference symbols Water tank 2 Water tank 3 Water tank 5 4 Shaking table 5 Heating device 6 Heating device 7 Heating device 8th Temperature adjustment knob 10 9 Temperature adjustment knob 10 Temperature adjustment knob 11 First sample carrier, tray 12 Stand 13 second shelf 15 14 Grooved plate 15 Recesses for sample 16 16 rehearse 17 probe 18 Display 20 19 Temperature setting button 20 Signal lamp 21 Rubber sleeve 22 Frame angle 23 Screws 25 24 Outer cover 25 Lid 26 Water drainage device 27 block 28 Arm of a shaking mechanism 30 29 Drive unit of a shaking mechanism

• * 9

Functional principle

reverse hybridization technique

DNA and RNA amplification products on oligonucleotide probes

1. DNA/RNA extraction from blood or serum

2. Amplification of DNA or cDNA with biotinylated primers

3. Hybridization (attachment at specific, precise temperatures) of the biotinylated PCR products to genotype-specific probes on nitrocellulose strips

4. Attachment of streptavidin-coupled enzyme and conversion of the chromogenic substrate

Claims (9)

- 14 - Medipro 17 June 1996 Medical Diagnostic Products GmbH M 21780 GM2 DS/hi Protection claims 1. Water bath shaker for carrying out chemical or biochemical &iacgr;&ogr; investigations, wherein samples (16) are shaken by means of a controlled shaking serbads are kept at a certain temperature,
characterized, that several water containers (1, 2, 3) are arranged with their base on the surface of a shaking table (4) or in a block (27) with a shaking mechanism and are fixed there, that sample carriers (11) provided in the water containers (1, 2, 3) are height-adjustable so that samples (16) arranged on the sample carriers (11) are held below or above the water levels of the water containers (1, 2, 3), that the water containers (1, 2, 3) are each provided with a heating device (5, 6, 7) is individually assigned, that the heating devices (5, 6, 7) individually assigned to the water containers (1, 2, 3) can be regulated to different temperature values, and that a probe (17) is provided for detecting the actual value for the temperature control of each water tank (1, 2, 3) independently of one another. 2. Water bath shaker according to claim 1, characterized in that the sample carriers (11) are mounted on stands (12) approximately in the region of the second quarter of the height of the water containers (1, 2, 3), measured from above, are arranged, whereby an air space is created above the sample carrier (11). 3. Water bath shaker according to one of the preceding claims, characterized in that the sample carriers (11) have holding elements for plates (14) that can be inserted into the water containers (1, 2, 3), and that the plates (14) are detachably attached to the sample carrier (11). 4. Water bath shaker according to one of the preceding claims, characterized in that the individually assigned heating devices (5, 6, 7) are arranged in or on the water containers (1, 2, 3). 5. Water bath shaker according to one of claims 1 to 3, characterized in that the heating devices (5, 6, 7) are installed in the shaking table (4) or in the table (27) at the location of the water containers (1, 2, 3). 6. Water bath shaker according to one of the preceding claims, characterized in that the probes (17) are attached to the sample carriers (11), which can be made of stainless metal. 7. Water bath shaker according to one of the preceding claims, characterized in that the water containers (1, 2, 3) can each be covered with an angled lid (24) which is designed in such a way that water evaporated from the water containers (1, 2, 3) runs back into the water containers. 8. Water bath shaker according to one of claims 3 to 7, characterized in that the plates (14) have recesses (15), which can be made of metal, for receiving samples (16), and that the recesses (15) are designed in such a way that they have a - 16 - Enable storage of the samples (16) without contact with the water in the water containers (1, 2, 3), while they are surrounded by the water in the water containers (1, 2, 3) on their side facing away from the opening of the water containers (1, 2, 3).
s 9. Water bath shaker according to one of the preceding claims, characterized in that the water containers (1, 2, 3), which consist of glass, plastic or metal, have a rectangular or circular cross-section, that the water containers (1, 2, 3) can have a width of 18 cm, a depth of 18 cm and a height of 15 cm, that the water containers (1, 2, 3) can be filled with a water quantity of approximately 3240 cm ³ , and that the numerical ratio of the cross-sectional area of the water containers (1, 2, 3) in cm ² to the height of the water containers (1, 2, 3) in cm can be selected in the range from 15 to 25.