U.S. patent application number 11/651986 was filed with the patent office on 2007-05-17 for device for the carrying out of chemical or biological reactions.
This patent application is currently assigned to Applera Corporation. Invention is credited to Wolfgang Heimberg, Thomas Hermann, Matthias Knulle, Markus Schurf, Tilmann Wagner.
Application Number | 20070110634 11/651986 |
Document ID | / |
Family ID | 8079714 |
Filed Date | 2007-05-17 |
United States Patent
Application |
20070110634 |
Kind Code |
A1 |
Heimberg; Wolfgang ; et
al. |
May 17, 2007 |
Device for the carrying out of chemical or biological reactions
Abstract
The invention relates to a device for the carrying out of
chemical or biological reactions with a reaction vessel receiving
element for receiving a microtiter plate with several reaction
vessels, wherein the reaction vessel receiving element has several
recesses arranged in a regular pattern to receive the respective
reaction vessels, a heating device for heating the reaction vessel
receiving element, and a cooling device for cooling the reaction
vessel receiving element. The invention is characterized by the
fact that the reaction vessel receiving element is divided into
several segments. The individual segments are thermally decoupled
from one another, and each segment is assigned a heating device
which may be actuated independently of the others. By means of the
segmentation of the reaction vessel receiving element, it is
possible for zones to be set and held at different temperatures.
Since the reaction vessel receiving element is suitable for
receiving standard microtiter plates, the device according to the
invention may be integrated in existing process sequences.
Inventors: |
Heimberg; Wolfgang;
(Ebersberg, DE) ; Hermann; Thomas; (Ottobrunn,
DE) ; Knulle; Matthias; (Grafing, DE) ;
Schurf; Markus; (Siegsdorf, DE) ; Wagner;
Tilmann; (Grafing, DE) |
Correspondence
Address: |
MH2 TECHNOLOGY LAW GROUP
1951 KIDWELL DRIVE
SUITE 550
TYSONS CORNER
VA
22182
US
|
Assignee: |
Applera Corporation
|
Family ID: |
8079714 |
Appl. No.: |
11/651986 |
Filed: |
January 11, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10089136 |
Dec 23, 2002 |
|
|
|
PCT/EP00/09569 |
Sep 29, 2000 |
|
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11651986 |
Jan 11, 2007 |
|
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Current U.S.
Class: |
422/400 |
Current CPC
Class: |
B01L 7/52 20130101; B01L
2200/147 20130101; B01L 7/54 20130101; B01L 2300/0829 20130101;
B01L 2300/1822 20130101 |
Class at
Publication: |
422/102 |
International
Class: |
B01L 3/00 20060101
B01L003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 1, 1999 |
DE |
29917313.5 |
Claims
1-17. (canceled)
18. A thermocycler for processing biological or chemical samples,
comprising: a block configured to receive a plurality of sample
volumes, the block defining a plurality of segments each configured
to receive a respective set of the plurality of sample volumes; and
a plurality of thermoelectric devices, wherein each thermoelectric
device corresponds to a respective segment of the block and a
respective set of the sample volumes to provide heating and
cooling.
19. The thermocycler of claim 18, wherein the block defines a
plurality of recesses.
20. The thermocycler of claim 19, wherein each of the recesses is
configured to receive a respective vessel of a sample holder
configured to hold the plurality of sample volumes.
21. The thermocycler of claim 18, wherein the block is configured
to receive one microtiter plate configured to hold the plurality of
sample volumes and wherein each of the plurality of segments of the
block is configured to receive a respective portion of the
microtiter plate.
22. The thermocycler of claim 18, further comprising a plurality of
temperature sensors, wherein each segment is associated with at
least one temperature sensor for measuring a temperature of the
segment.
23. The thermocycler of claim 18, further comprising a plurality of
heating elements disposed and configured to respectively provide
heating to each of the segments.
24. The thermocycler of claim 23, wherein the plurality of heating
elements are configured to respectively equalize a temperature of
each of the plurality of segments.
25. The thermocycler of claim 23, wherein the plurality of heating
elements is configured to provide heating to each segment to
respective substantially uniform preset temperatures.
26. The thermocycler of claim 23, further comprising a plurality of
temperature equalisation plates disposed and configured to
respectively control a temperature of each of the segments to about
respective substantially uniform temperatures, wherein each
temperature equalization plate is associated with at least one of
the plurality of heating elements.
27. The thermocycler of claim 23, further comprising a cover,
wherein the plurality of heating elements are associated with the
cover.
28. The thermocycler of claim 23, wherein the plurality of heating
elements comprise heating elements chosen from heating coils,
heating films, heating foils, semiconductor heating elements, and
thermoelectric devices.
29. The thermocycler of claim 23, wherein the plurality of heating
elements are independently controllable.
30. The thermocycler of claim 18, further comprising a plurality of
heat pipes, wherein each heat pipe is disposed and configured to
respectively exchange heat with each of the segments.
31. The thermocycler of claim 18, further comprising at least one
cooling element configured to provide cooling to the block.
32. The thermocycler of claim 31, wherein the at least one cooling
element comprises a plurality of cooling elements disposed and
configured to respectively provide cooling to each of the
segments.
33. The thermocycler of claim 32, wherein the plurality of cooling
elements comprise a plurality of fluid-based heat exchangers.
34. The thermocycler of claim 31, wherein the cooling element
extends over an area at least as large as a combined area defined
by the plurality of segments.
35. A method for processing biological or chemical samples, the
method comprising: disposing a plurality of sample volumes in
conjunction with a block having a plurality of segments, wherein
each segment of the block receives a respective set of the
plurality of sample volumes; modulating a temperature of a first
segment of the block via a first thermoelectric device such that
the first segment reaches a first preset temperature, wherein the
first thermoelectric device corresponds to a first set of the
plurality of sample volumes to provide heating and cooling; and
modulating a temperature of a second segment via a second
thermoelectric device such that the second segment reaches a second
preset temperature, wherein the second thermoelectric device
corresponds to a second set of the plurality of sample volumes to
provide heating and cooling.
36. The method of claim 35, wherein disposing the plurality of
sample volumes comprises disposing one microtiter plate configured
to hold the plurality of sample volumes in conjunction with the
block such that each segment of the block receives a respective
portion of the microtiter plate.
37. The method of claim 36, wherein disposing the microtiter plate
comprises disposing the microtiter plate such that the first
thermoelectric device corresponds to a first portion of the
microtiter plate and the second thermoelectric device corresponds
to a second portion of the microtiter plate.
38. The method of claim 35, wherein the first temperature
corresponds to an annealing temperature of at least the sample
volumes in the first set.
39. The method of claim 35, wherein the first temperature
corresponds to a denaturing temperature of at least the sample
volumes in the first set.
40. The method of claim 35, wherein the first temperature
corresponds to an elongation temperature of at least the sample
volumes in the first set.
41. The method of claim 35, wherein the first temperature and the
second temperature differ from each other.
42. The method of claim 35, further comprising equalizing the
respective temperatures of the first and second segments via first
and second heating elements disposed so as to respectively exchange
heat with the first and second segments.
43. The method of claim 35, wherein modulating the temperature of
the first segment comprises modulating the temperature of the first
segment at a first rate and modulating the temperature of the
second segment comprises modulating the temperature of the second
segment at a second rate.
44. The method of claim 43, wherein the first rate and the second
rate differ from each other.
45. The method of claim 35, further comprising maintaining the
first segment at the first preset temperature for a first residence
time and maintaining the second segment at the second preset
temperature for a second residence time
46. The method of claim 45, wherein the first residence time and
the second residence time differ from each other.
47. The method of claim 35, wherein modulating the temperature of
the first segment and the second segment comprises modulating at
least one of temperature level, residence time at a temperature
level, and rate of change of temperature.
48. The method of claim 35, wherein modulating the temperature of
the first segment comprises modulating the temperature according to
a first temperature cycle and modulating the temperature of the
second segment comprises modulating the temperature according to a
second temperature cycle.
49. The method of claim 48, wherein the first temperature cycle
differs from the second temperature cycle. and the second
temperature cycle are the same.
Description
[0001] The present invention relates to a device for the carrying
out of chemical or biological reactions with [0002] a reaction
vessel receiving element for receiving reaction vessels, wherein
the reaction vessel receiving element has several recesses arranged
in a regular pattern to receive reaction vessels, a heating device
for heating the reaction vessel receiving element, and a cooling
device for cooling the reaction vessel receiving element.
[0003] Such devices are described as thermocyclers or thermocycling
devices and are used to generate specific temperature cycles, i.e.
to set predetermined temperatures in the reaction vessels and to
maintain predetermined intervals of time.
[0004] A device of this kind is known from U.S. Pat. No. 5,525,300.
This device has four reaction vessel receiving elements, each with
recesses arranged in a regular pattern. The pattern of the recesses
corresponds to a known pattern of reaction vessels of standard
microtiter plates, so that microtiter plates with their reaction
vessels may be inserted in the recesses.
[0005] The heating and cooling devices of a reaction vessel
receiving element are so designed that a temperature gradient
extending over the reaction vessel receiving element may be
generated. This means that, during a temperature cycle, different
temperatures may be obtained in the individual reaction vessels.
This makes it possible to carry out certain experiments at
different temperatures simultaneously.
[0006] This temperature gradient is used to determine the optimal
denaturing temperature, the optimal annealing temperature and the
optimal elongation temperature of a PCR reaction. To achieve this,
the same reaction mixture is poured into the individual reaction
vessels, and the temperature cycles necessary to perform the PCR
reaction are executed. Such a temperature cycle comprises the
heating of the reaction mixture to the denaturing temperature,
which usually lies in the range 90.degree.-95.degree. C., cooling
to the annealing temperature, which is usually in the range
40.degree.-60.degree. C., and heating to the elongation
temperature, which is usually in the range 70-75.degree. C. A cycle
of this kind is repeated several times, leading to amplification of
a predetermined DNA sequence.
[0007] Since a temperature gradient can be set, different but
predetermined temperatures are set in the individual reaction
vessels. After completion of the cycles it is possible to
determine, with the aid of the reaction products, those
temperatures at which the PCR reaction will give the user the
optimal result. Here the result may be optimised e.g. in respect of
product volume or also product quality.
[0008] The annealing temperature, at which the primer is added, has
a powerful influence on the result. However the elongation
temperature too can have beneficial or adverse effects on the
result. At a higher elongation temperature, the addition of the
bases is accelerated, with the probability of errors increasing
with higher temperature. In addition, the life of the polymerase is
shorter at a higher elongation temperature.
[0009] A thermocycling device, by which the temperature gradient
may be set, makes it much easier to determine the desired
temperatures, since a reaction mixture my simultaneously undergo
cycles at different temperatures in a single thermocycling
device.
[0010] Another important parameter for the success of a PCR
reaction is the residence time at the individual temperatures for
denaturing, annealing and elongation, and the rate of temperature
change. With the known device, these parameters can not be varied
in one test series for an individual reaction vessel holder. If it
is desired to test different residence times and rates of change,
this can be done in several test series either consecutively on one
thermocycling device or simultaneously in several thermocycling
devices.
[0011] For this purpose there are so-called multiblock
thermocycling devices with several reaction vessel receiving
elements, each provided with separate cooling, heating and control
devices (see U.S. Pat. No. 5,525,300). The reaction mixture to be
tested must be distributed over several microtiter plates, for
testing independently of one another.
[0012] To determine the optimal residence times and rates of
temperature change it is necessary to have either several
thermocycling devices or a multiblock thermocycling device, or to
carry out tests in several consecutive test series. The acquisition
of several thermocycling devices or of a multiblock thermocycling
device is costly and the carrying-out of several consecutive test
series takes too along. In addition, handling is laborious when
only part of the reaction vessels of several microtiter plates is
filled, with each of the latter being tested and optimised in
separate test series. This is especially disadvantageous in the
case of device which operate automatically and in which the
reaction mixtures are subject to further operations, since several
microtiter plates must then be handled separately. It is also
extremely impractical when only part of the reaction vessels of the
microtiter plates is filled, since the devices for further
processing, such as e.g. sample combs for transferring the reaction
products to an electrophoresis apparatus, are often laid out on the
grid of the microtiter plates, which means that further processing
is correspondingly limited if only part of the reaction vessels of
the microtiter plate is used.
[0013] U.S. Pat. No. 5,819,842 discloses a device for the
individual, controlled heating of several samples. This device has
several flat heating elements arranged in a grid pattern on a work
surface. Formed below the heating elements is a cooling device
which extends over all the heating elements. In operation a
specially designed sample plate is placed on the work surface. This
sample plate has a grid plate, covered on the underside by a film.
The samples are poured into the recesses of the grid plate. In this
device the samples lie on the individual heating elements,
separated from them only by the film. By this means, direct heat
transfer is obtained. The drawback of this device, however, is that
no commonly available microtiter plate can be used.
[0014] With increasing automation in biotechnology, thermocyclers
are increasingly being used in automated production lines and with
robots as one of several work stations. Here it is customary for
the samples to be passed in microtiter plates from one work station
to the next. If the device according to U.S. Pat. No. 5,819,842
were to be used in such an automated production process, it would
be necessary for the samples to be pipetted out of a microtiter
plate into the specially designed sample plate before temperature
adjustment, and from the sample plate into a microtiter plate after
temperature adjustment. Here there is a risk of contamination of
the samples. The use of this specially designed sample plate must
therefore be regarded as extremely disadvantageous.
[0015] The invention is based on the problem of developing the
device described above in such a way that the disadvantages
described above are avoided and the parameters of the PCR process
may be optimised with great flexibility.
[0016] To solve this problem the invention has the features
specified in claim 1. Advantageous developments thereof are set out
in the additional claims.
[0017] The invention is characterised by the fact that the reaction
vessel receiving element is divided into several segments, with the
individual segments thermally decoupled and each segment assigned a
heating device which may be actuated independently.
[0018] By this means the individual segments of the device may be
set to different temperatures independently of one another. This
makes it possible not only to set different temperature levels in
the segments, but also for them to be held for varying lengths of
time or altered at different rates of change. The device according
to the invention thus permits optimisation of all physical
parameters critical for a PCR process, while the optimisation
process may be carred out on a single reaction vessel receiving
element in which a microtiter plate may be inserted.
[0019] With the device according to the invention it is therefore
also possible to optimise the residence times and rates of
temperature change without having to distribute the reaction
mixture over different microtiter plates for this purpose.
[0020] The thermocycling device according to the invention is in
particular suitable for optimising the multiplex PCR process, in
which several different primers are used.
[0021] The above problem, and the features and advantages according
to the present invention, may be better understood from the
following detailed description of preferred embodiments of the
present invention and with reference to the associated
drawings.
[0022] The invention is explained in detail below with the aid of
the drawings. These show in:
[0023] FIG. 1 a section through a device according to the invention
for carrying out chemical or biological reactions in accordance
with a first embodiment,
[0024] FIG. 2 a section through an area of a device according to
the invention for carrying out chemical or biological reactions in
accordance with a second embodiment,
[0025] FIG. 3 a schematic plan view of the device of FIG. 2,
[0026] FIG. 4 a schematic plan view of a device according to a
third embodiment,
[0027] FIG. 5 an area of the device of FIG. 4 in a sectional view
along the line A-A,
[0028] FIGS. 6 to 9 schematic plan views of reaction vessel
receiving elements with differing segmentation
[0029] FIG. 10 a clamping frame in plan view
[0030] FIG. 11 a device according to the invention in which
segments of a reaction vessel receiving element are fixed by the
clamping frame according to FIG. 10, and
[0031] FIG. 12 a further embodiment of a device according to the
invention in section, in which segments of a reaction vessel
receiving element are fixed by the clamping frame according to FIG.
10.
[0032] FIG. 1 shows a first embodiment of the device 1 according to
the invention for carrying out chemical or biological reactions in
a schematic sectional view.
[0033] The device has a housing 2 with a bottom 3 and side walls 4.
Located just above and parallel to the bottom 3 is an intermediate
wall 5, on which are formed several bases 5a. In the embodiment
shown in FIG. 1, a total of six bases 5a are provided, arranged in
two rows of three bases 5a each.
[0034] Mounted on each of the bases 5a is a heat exchanger 6, a
Peltier element 7 and a segment 8 of a reaction vessel receiving
element 9. The heat exchanger 6 is part of a cooling device and the
Peltier element 7 is part of a combined heating and cooling device.
The elements (heat exchanger, Peltier element, segment) mounted on
the bases 5a are bonded by an adhesive resin with good heat
conducting properties, so that good heat transfer is realised
between these elements, and the elements are also firmly connected
to a segment element 10, the device has altogether six such segment
elements 10. Instead of adhesive resin, a heat conducting film or a
heat conducting paste may also be provided.
[0035] Each of the segments 8 of the reaction vessel receiving
element 9 has a base plate 11 on which tubular, thin-walled
reaction vessel holders 12 are integrally formed. In the embodiment
depicted in FIG. 1, in each case 4.times.4 reaction vessel holders
12 are arranged on a base plate 11. The distance d between adjacent
segments 8 is such that the reaction vessel holders 12 of all
segments 8 are arranged in a regular pattern with constant grid
spacing D. The grid spacing D is chosen so that s standardised
microtiter plate with its reaction vessels may be inserted in the
reaction vessel holders 12.
[0036] By providing the distance d between adjacent segments, an
air gap which thermally decouples the segments 8 and segment
elements 10 respectively is formed.
[0037] The reaction vessel holders 12 of the device shown in FIG. 1
form a grid with a total pf 96 reaction vessel holders, arranged in
eight rows each with twelve reaction vessel holders 12.
[0038] The Peltier elements 7 are each connected electrically to a
first control unit 13. Each of the heat exchangers 6 is connected
via a separate cooling circuit 14 to a second control unit 15. The
cooling medium used is for example water, which is cooled in the
cool temperature control unit before transfer to one of the heat
exchangers 6.
[0039] The first control unit 13 and the second control unit 15 are
connected to a central control unit 16 which controls the
temperature cycles to be implemented in the device. Inserted in
each cooling circuit 14 is a control valve 19, which is controlled
by the central control unit 16 to open or close the respective
cooling circuit 14.
[0040] Pivotably attached to the housing 2 is a cover 17 in which
additional heating elements 18 in the form of Peltier elements,
heating films or semiconductor heating elements may be located. The
heating elements 18 form cover heating elements, each assigned to a
segment 8 and separately connected to the first control unit 13, so
that each heating element 18 may be individually actuated.
[0041] The mode of operation of the device according to the
invention is explained in detail below.
[0042] There are three modes of operation.
[0043] In the first operating mode all segments are set to the same
temperature, i.e. the same temperature cycles are run on all
segments. This operating mode corresponds to the operation of a
conventional thermocycling device.
[0044] In the second operating mode the segments are actuated with
different temperatures, wherein the temperatures are so controlled
that the temperature difference .DELTA.T of adjacent segments 8 is
less than a predetermined value K which amounts for example to
5.degree.-15.degree. C. The value to be chosen for K depends on the
quality of the thermal decoupling. The better the thermal
decoupling, the greater the value which can be chosen for K.
[0045] The temperature cycles input by the user may be distributed
automatically by the central control unit 16 to the segments 8, so
that the temperature differences between adjacent segments are kept
as small as possible.
[0046] This second operating mode may be provided with a function
by which the user inputs only a single temperature cycle or PCR
cycle, and the central control unit 16 then varies this cycle
automatically. The parameters to be varied, such as temperature,
residence time or rate of temperature change, may be chosen by the
user separately or in combination. Variation of the parameters is
effected either by linear or sigmoidal distribution.
[0047] In the third operating mode, only part of the segments is
actuated. In plan view (FIG. 3, FIG. 4, FIGS. 6 to 9) the segments
8 have side edges 20. In this operating mode, the segments 8
adjacent to the side edges of an actuated segment 8 are not
actuated. If the segments 8 themselves form a regular pattern (FIG.
3, FIG. 4, FIG. 6, FIG. 7 and FIG. 8), then the actuated segments
are distributed in a chessboard pattern. In the embodiments shown
in FIGS. 1 to 4, three of the six segments 8 can be actuated,
namely the two outer segments of one row and the middle segment of
the other row.
[0048] In this operating mode the actuated segments are not
influenced by the other segments, and their temperature may be set
completely independently of the other actuated segments. By this
means it is possible to run quite different temperature cycles on
the individual segments, with one of the segments for example
heated up to the denaturing temperature and another held at the
annealing temperature. Thus it is possible for the residence times,
i.e. the intervals of time for which the denaturing temperature,
the annealing temperature and the elongation temperature are held,
also the rates of temperature change, to be set as desired, and run
simultaneously on the individual segments. In this way it is
possible to optimise not only the temperatures, but also the
residence times and the rates of temperature change.
[0049] In this operating mode it may be expedient to heat the
non-actuated segments 8 a little, so that their temperature lies
roughly in the range of the lowest temperature of the adjacent
actuated segments. This avoids the non-actuated segments forming a
heat sink for the actuated segments and affecting their temperature
profile adversely.
[0050] A second embodiment of the device according to the invention
is shown in FIGS. 2 and 3. The basic design corresponds to that of
FIG. 1, so that identical parts have been given the same reference
number.
[0051] The second embodiment differs from the first embodiment by
virtue of the fact that the side edges 20 of the segments 8
adjacent to the side walls 4 of the housing 2 engage in a slot 21
running round the inner face of the side walls 4, and are fixed
therein for example by bonding. By this means the individual
segment elements 10 are fixed in space, thereby ensuring that
despite the form of the gaps between the segment elements 10, all
reaction vessel holders 12 are arranged in the pattern of the
reaction vessels of a microtiter plate. The side walls 4 of the
housing 2 are made of a non heat conducting material. This
embodiment may also be modified such that the slot 21 is introduced
in a frame formed separately from the housing 2. The frame and the
segments inserted in it form a part which may be handled separately
during production and is bonded to the heating and cooling
devices.
[0052] A third embodiment is shown schematically in FIGS. 4 and 5.
In this embodiment, ties 22 of non heat conducting material are
located somewhat below the base plates 11 of the segments 8 in the
areas between the segment elements 10 and between the segment
elements 10 and the side walls 4 of the housing 2. On the side
edges 20 of the segments 8 and of the base plates 11 respectively
are formed hook elements 23 which are bent downwards. These hook
elements 23 engage in corresponding recesses of the ties 22 (FIG.
5), thereby fixing the segments 8 in their position. The hook
elements 23 of adjacent segments 8 are offset relative to one
another. The ties 22 thus form a grid, into each of the openings of
which a segment 8 may be inserted.
[0053] This type of position fixing is very advantageous since the
boundary areas between the segments 8 and the ties 22 are very
small, so that heat transfer via the ties 22 is correspondingly
low. Moreover this arrangement is easy to realise even in the
confined space conditions between adjacent segment elements.
[0054] Shown in schematic plan view in FIGS. 6 to 9 are reaction
vessel receiving elements 9 which represent further modifications
of the device according to the invention. In these reaction vessel
receiving elements 9, the individual segments 8 are joined by webs
24 of a thermally insulating material joined to form a single unit
The ties 22 are arranged between the side edges 20 of the base
plates 11, to which they are fixed for example by bonding.
[0055] The segmentation of the reaction vessel receiving element of
FIG. 6 corresponds to that of the first and second embodiment (FIG.
1-3), in which 4.times.4 reaction vessel holders are arranged on
each segment 8.
[0056] The reaction vessel receiving element 9 shown in FIG. 7 is
comprised of 24 segments 8 each with 4.times.4 reaction vessel
holders 12, while the segments 8 are in turn connected by means of
thermally insulating webs 24.
[0057] In the reaction vessel receiving element 9 shown in FIG. 8,
each segment 8 has only a single reaction vessel holder 12.
[0058] For the relatively finely sub-divided reaction vessel
receiving elements 9 it is expedient to integrate temperature
sensors in the thermocycling device. These temperature sensors
sense the temperatures of the individual segments, so that the
temperature of the segments 8 is regulated in a closed control loop
on the basis of the temperature values determined by the
temperature sensors.
[0059] Infrared sensors may for example be used as temperature
sensors, located e.g. in the cover. With this sensor arrangement it
is possible to sense the temperature of the reaction mixture
directly.
[0060] FIG. 9 shows a reaction vessel receiving element 9 with six
segments 8, rectangular in plan view, and a segment 8a in the form
of a double cross formed by three intersecting rows of reaction
vessel holders 12. The six rectangular segments 8 are each
separated from the next rectangular segment by a row or column of
reaction vessel holders. This segmentation is especially
advantageous for the third operating mode described above, since
the rectangular segments 8 are not in contact with one another and
may therefore be actuated simultaneously as desired, with only the
segment 8a in the form of a double cross not being actuated.
[0061] The segments 8 of the reaction vessel receiving element 9
are made from a metal with good heat conducting properties, e.g.
aluminum. The materials described above as non-heat conducting
materials or thermally insulating materials are either plastics or
ceramics.
[0062] A further embodiment of the device according to the
invention is shown In FIG. 11. In this embodiment the individual
segments 8b of the reaction vessel receiving element 9 are fixed in
position by means of a clamping frame 25 (FIG. 10).
[0063] The clamping frame 25 is grid-shaped and formed by
longitudinal ties 26 and cross ties, wherein the ties 26, 27 span
openings. Through these openings extend the reaction vessel holders
12 of the segments 8b. In the present embodiment, the ties 26, 27
are for instance in positive contact with the reaction vessel
holders 12 and with the base plate 11 which protrudes from the
reaction vessel holders. The 25 is provided with holes 28, through
which pass bolts 29 for fixing the clamping frame to a
thermocycling device 1.
[0064] Located below each of the segments 8b is a separately
actuable Peltier element 7 and a cooling element 30 which extends
over the area of all the segments 8b. Located in each case between
the cooling element 30 and the Peltier element 7, and between the
Peltier element 7 and the respective segment 8b is a heat
conducting foil 31. The cooling element 30 is provided with holes
through which extend the bolts 29, each fixed by a nut 32 to the
side of the cooling element 30 facing away from the reaction vessel
receiving element 9.
[0065] The clamping frame 25 is made from a non heat conducting
material, in particular POM or polycarbonate. It therefore allows a
fixing of the segments 8b of the reaction vessel receiving element
9 wherein the individual elements between the segments 8b and the
cooling element 30 are under tension, thereby ensuring good heat
transfer in the vertical direction between the individual elements.
Since the clamping frame itself has poor heat conducting
properties, the heat transfer between two adjacent segments 8b is
kept low. For further reduction of heat transfer between two
adjacent segments, the surfaces of the clamping frame 25 in contact
with the segments 8b may be provided with narrow webs, so that in
the areas adjoining the webs, air gaps are formed between the
clamping frame 25 and the segments 8b.
[0066] In the embodiment shown in FIG. 11, a so-called heat pipe 33
is fitted between every two rows of reaction vessel holders 12.
Such a heat pipe is distributed for example by the company
THERMACORE INTERNATIONAL, Inc., USA. It is comprised of a gastight
jacket, in which there is only a small amount of fluid. The
pressure in the heat pipe is so low that the fluid is in a state of
equilibrium between the liquid and the gaseous aggregate state, and
consequently evaporates at a warmer section of the heat pipe and
condenses at a cooler section. By this means, the temperature
between the individual sections is equalised. The fluid used is,
for example, water or freon.
[0067] Through integration of such a heat pipe in the segments 8b
of the reaction vessel receiving element 9, a temperature
equalisation is effected over the segment 8b. By this means it is
ensured that the same temperature is present over the whole segment
8b.
[0068] A further embodiment of the thermocycling device 1 according
to the invention is shown in FIG. 12. The design of this
thermocycling device 1 is similar to that of FIG. 11, therefore
similar parts have been given the same reference numbers.
[0069] The segments 8c of this thermocycling device 1, however,
have no heat pipe. Instead of heat pipes, a temperature
equalisation plate 34 is provided in the area beneath each of the
segments 8c. These temperature equalisation plates 34 are flat
elements with a surface corresponding to the basic surface of one
of the segments 8c. These temperature equalisation plates 34 are
hollow bodies with a small amount of fluid, and work on the same
principle as the heat pipes. By this means it is once again ensured
that there are no temperature variations within a segment 8c.
[0070] The temperature equalisation plate may however be made from
materials with very good heat conducting properties, such as e.g.
copper. Additional heating and/or cooling elements, e.g. heating
foils, heating coils or Peltier elements, may be integrated in such
a temperature equalisation plate. The heating and cooling elements
support homogeneity and permit more rapid heating and/or cooling
rates. A Peltier element, which generally does not have an even
temperature distribution, is preferably combined with a flat
heating element.
[0071] The invention is described above with the aid of embodiments
with 96 recesses for receiving a microliter plate with 96 reaction
vessels. The invention is not however limited to this number of
recesses. Thus for example the reaction vessel receiving element
may also have 384 recesses to receive a corresponding microtiter
plate. With regard to features of the invention not explained in
detail above, express reference is made to the claims and the
drawing.
[0072] In the embodiments described above, a cooling device with a
fluid cooling medium is used. Within the scope of the invention it
is also possible to use a gaseous cooling medium, in particular air
cooling, instead of a fluid cooling medium.
[0073] The reaction vessel receiving elements described above are
comprised of a base plate with roughly tubular reaction vessel
holders. Within the scope of the invention it is also possible to
use a metal block, in which recesses to receive the reaction
vessels of the microtiter plate are made.
List of References
[0074] 1 thermocycling device [0075] 2 housing [0076] 3 bottom
[0077] 4 side wall [0078] 5 intermediate wall [0079] 5a base [0080]
6 heat exchanger [0081] 7 Peltier element [0082] 8 segment [0083]
8a segment in the form of a double cross [0084] 9 reaction vessel
receiving element [0085] 10 segment element [0086] 11 base plate
[0087] 12 reaction vessel holder [0088] 13 first control unit
[0089] 14 cooling circuit [0090] 15 second control unit [0091] 16
central control unit [0092] 17 cover [0093] 18 heating element
[0094] 19 control valve [0095] 20 side edge [0096] 21 slot [0097]
22 ties [0098] 23 hook element [0099] 24 web [0100] 25 clamping
frame [0101] 26 longitudinal tie [0102] 27 cross tie [0103] 28 hole
[0104] 29 bolt [0105] 30 cooling element [0106] 31 heat conducting
foil [0107] 32 nut [0108] 33 heat pipe [0109] 34 temperature
equalisation plate
* * * * *