FR2496266A1 - THERMOSTATIC PLATES EQUIPPED WITH AN ELECTROPHORESIS DEVICE - Google Patents

Abstract

IN A THERMOSTATIC PLATE 10 EQUIPPING WITH AN ELECTROPHORESIS DEVICE, THE MATERIAL TO BE EXAMINED TRAVELS A FLAT LAYER OF GEL IN A DIRECTION LOCATED IN THE PLAN OF THE SAID LAYER. BETWEEN TWO UPPER 14 AND LOWER 12 GLASS PLATES, FLAT, PARALLEL AND DISTANT FROM ONE OF THE OTHER, IS AN INTERNAL SPACE 28 CLOSED BY A SPACER 16 CONNECTED, PREFERREDLY GLUED, TO THE TWO PLATES 14, 12. THIS SPACER 16 INCLUDES LONGITUDINAL 20, 22 AND TRANSVERSAL 24, 26 TRUNCONS AND IT IS PUNCHED BY INTERMEDIATE CAVITES 34, 36 IN WHICH ADMISSION 30 AND OUTLET 32 CONNECTIONS ARE GLUED ALLOWING A HEAT EXCHANGER TO MAKE A ZIGZ PATH 38 THROUGH THE PLATE. THIS ROUTE 38 IS DELIMITED BY GUIDANCE STRIPS 40 ARRANGED IN QUINCONCE.

Description

Thermostatic plate fitted to an electro-

  phoresis. The present invention relates to a thermostatic plate fitted to an electrophoresis device, in which a material to be examined passes through a layer of gel in a direction of movement situated in the plane of said layer of gel, and comprising a housing delimiting a space internal and having at least two connections which, mounted on said housing and communicating with the internal space, allow the passage of means

  heat exchangers in said plate.

  A known thermostatic plate of this type, which has sufficient thermal constancy to obtain

  high operating temperatures (up to

  approximately 800C) necessary for electrophoresis, comprises a housing produced from metal sheets joined to each other by brazing. The material and production costs of this known plate are relatively high. It is difficult to supervise the path of the material to be examined through the gel layer, because

  this known plate is not transparent.

  The present invention therefore aims to

  throw a thermostatic plate of the aforementioned type which, pre-

  feeling good thermal constancy, can be achieved

  low cost and facilitates the control of the

  ment of the material to be examined through the gel layer.

  According to the essential characteristics of the

  vention, two flat glass plates, parallel and dis-

  aunts from each other, are separated by a spacer which, running along the periphery of each of said plates and possibly comprising several parts, is connected,

  preferably glued to these plates and closes the space

  dull between these. The glass plates assembled to one another have the great thermal constancy necessary. It should only be ensured that no sudden heating or cooling of the

2 2496266

  thermostatic plate does not occur. Glass plates

  necessary to realize the set are available ai-

  quietly and inexpensively; the assembly of these glass plates can be carried out quickly and simply, especially when said plates are glued to the spacers. Because these flat plates are transparent, it is

  possible to observe or illuminate through them the

  che gel. When the support plate for this gel layer also consists of a glass plate, it is advantageously possible to illuminate the gel layer by transparency, which, in most cases, is

  more favorable than incident lighting. It is particularly

  highly advantageous than glass plates having a

  excellent flatness can be used. This is no-

  especially important when a very thin layer of gel,

  for example with a thickness of 0.02 mm to 1.5 mm, is applied

  quée on one of the two glass plates. Finally, the thermostatic plate according to the invention is substantially more

  as light as the metal thermostatic plate of the pre-

  cited and hence it is considerably easier

  To manipulate. This is particularly noticeable in pre-

  sence of interchangeable experimental setups -and when-

  that it is more advantageous to extract the thermosta- plate

  tick of the experimental setup with a view to applying or

lift the gel layer.

  Of course, a Plexiglas thermostatic plate is also known. However, it does not present the

  high thermal constancy required. The calorific power

  the size of this known plate is relatively small,

  which is notably due to the high thermal resistance

  than the material used. It is not possible to

  Brick a Plexiglas thermostatic plate with the same dimensional accuracy (notably flatness of the

  side of gel application) and the same dimension consistency-

  as the thermostatic plate according to the invention.

  In addition, a thermostatic plate is also known.

  tick constituted by a block of cast glass having the internal space intended to receive the heat exchanger means. The thermal constancy of this block of glass is not sufficient, which is due in particular to the inevitable internal stresses manifested in the block after casting. It results from the relatively large height and the generally irregular wall thickness,

  both a low color power and a homogeneous-

  insufficient thermal ity prevailing on the surface. This block

  glass is heavy and, therefore, allows only one manipulation

  limited relationship. This block of glass is only translucent, and not transparent, so that it is impossible to control the progress of the electrophoresis through this block. It is not essential to provide, in the glass plates, recesses intended for the fittings to be provided when, in accordance with the invention, these fittings

  are arranged, preferably glued in the region of the

tretoise between said plates.

  According to the invention, the glass plate

  closest to the gel layer has a thick

  from 1 mm to 4 mm, preferably from 1.4 mm to 1.8 mm and, optimally, about 1.5 mm; the thickness of the glass plate located furthest from the gel layer reaching from 2 mm to 4 mm, optimally about 3 mm. Thus, the thermal resistance manifested between

  the circulating heat exchanger and the gel is

  pick, which results in better heat transmission and therefore better consistency over time and space of the gel temperature, particularly when the gel layer is directly applied to the glass plate immediately

  neighbor. The glass plate with the largest thickness-

  sor and distant from the gel layer has the function of

  provide the desired mechanical stability.

  It has proven to be important, when simul-

  temporarily the electrophoresis of several samples of material, that the temperature of the gel is as constant as possible in the direction perpendicular to the direction of movement, so that one obtains in this layer of gel straight bands of path of the individual samples , clearly separated from each other. To maintain the desired thermal consistency

  perpendicular to the direction of travel, the invention

  tion suggests guiding the heat exchanger through

  internal space along an essentially perpendicular path

  Cular to the direction of travel, path presenting

  possibly one or more changes of direction.

  In the presence of a thermostatic plate arranged longitu-

  linearly in the direction of movement, the heat exchanger crosses the internal space along a substantially zigzag path. The drop in temperature along part of this trajectory between two bifurcations is relatively small, which guarantees consistency

  thermal demand perpendicular to the direction of the

  placement. Since the temperature of the gel can

  actually vary to some extent in the direction

  displacement, it is possible to choose a dimension

  relatively large extension (e.g. 90 cm) of the

  thermostatic plate oriented in the direction of travel

  cement, even when the calorific value of the

  heat gor is relatively low. Therefore, long layers of gel can be used

  with good dimensional resolution corresponding

  dante. To properly guide the heat exchanger through the internal space, at least one strip of

  guidance perpendicular to the direction of travel is advantageous-

  according to the invention, housed in said internal space. When camoe the

  further provides the present invention, this tape guide

  dage is glued to the two glass plates, a robust mechanical arrangement is obtained, which guarantees that the glass plate contiguous to the gel layer retains its flatness, even when it is subjected to stress, for example during an increase in the pressure imposed by the exchanger

of heat in the internal space.

  Furthermore, to further improve the cons-

  thermal resistance in the direction perpendicular to the direction

  tion of the displacement, it is proposed to produce the guide strip in a thermally conductive material, by

  example of copper, aluminum or fine steel.

  Preferably, the spacer runs along essentially

  tiel the sides of a rectangle comprising longitudinal sections parallel to the direction of movement and transverse connecting sections. One of the

  fittings can then be arranged in the region of an ex-

  end of one of the longitudinal sections, while the other connection is in the vicinity of one end of the other longitudinal section, possibly also close to the adjacent end considered of one of the

cross sections.

  In one embodiment according to the invention, the two connectors are arranged in end zones of the longitudinal sections that are distant one

  on the other in the direction of movement, the guide strips

  dage then having a length less than the space separating said sections, in which case said guide strips are further distributed over the length of the longitudinal sections, starting alternately from one and the other of the latter. Thus, with particularly simple means, we define the zigzag path

  traversed by the heat exchanger in the internal space.

  In another embodiment, the two sections are located in the end zones of the longitudinal sections arranged at the same height in the direction of movement, in which case the internal space accommodates an additional strip parallel to the direction of movement and

  located a short distance from one of said sections along

  gitudinal, the length of this strip being less than the interval between the transverse sections this additional strip starts from the transverse section closest to the connections, in which case the strips

  guide inserted between said additional strip

  re and the other longitudinal section have a shorter length

  less than the interval between said additional band

  and the other longitudinal section; said ban-

  guide, distributed along the length of said additional strip, leave alternately from this

  last and the other longitudinal section.

  The thermostatic plate according to the invention is particularly suitable for use during the electrophoresis of biological macromolecules by means of a layer of gel applied to one of the glass plates and having a thickness of between 0.02 mm and 1 , 5 mm. This is due, among other things, to the good flatness of this glass plate, to the great length of the latter, which can be obtained by simple means;

  the favorable temperature distribution over the

  face of said glass plate; as well as handling

easy from the thermostatic plate.

  The invention will now be described in more detail with reference to the accompanying drawings by way of non-limiting examples and in which FIG. 1 is a plan view of a first embodiment of a thermostatic plate according to

  the invention, the upper glass plate of which is illus-

very torn away;

  Figure 2 is a cross section of the plate

  that of Figure 1, along the line II-II; and Figure 3 is a plan view of a second embodiment, the upper glass plate

has been removed.

  In a first embodiment illustrated in FIGS. 1 and 2, a thermostatic plate generally bears the reference 10. It comprises two glass plates, a lower glass plate 12 and a plate

  upper glass 14 (Figure 2), occupying positions

  parallel positions superimposed and maintained at a determined distance from each other by a spacer 16 in several parts. The two glass plates 12 and 14 have the same configuration (see FIG. 1), but

  different thicknesses. The thickness a of the lower plate

  upper 12 is 3 mm, the thickness b of the upper plate reaching 1.5 mm. The upper face 18, oriented outside the upper plate 14 (FIG. 2), has undergone a preliminary treatment by which it repels the gel, in order to facilitate the detachment of the layers of gel coming into contact with said upper face 18. The

  two plates, just like the spacer 16 in several parts

  ties, are made of ice glass which, while presenting

  both the required dimensional accuracy, in particular the flatness of the upper plate 14, can be obtained at

relatively inexpensive.

  Spacer 16 runs along the rectangular configuration

  glass plates 12 and 14. It comprises two longitudinal sections, oriented from top to bottom on the

  figure 1 and of which the left and right sections carry

  refer to references 20 and 22 respectively; as well as two lower transverse sections 24 and upper 26 (FIG. 1), which connect the ends of the longitudinal sections. The spacer 16 constitutes in itself a closed frame and it thus delimits an internal space 28 between the glass plates 12 and 14. In order to be able to pass this internal space 28 through a heat exchanger means, for example water heated by an individual device

  with thermostat, two connections are provided, one connection

  mission 30 and an outlet fitting 32. The fitting of

  mission 30 is located near the lower end of the longitudinal section 22, and the latter is interrupted for this purpose. The inlet connector 30 is glued into an intermediate cavity 34 thus delimited, the entire space

  residual of this cavity 34 being filled with glue.

  In an analogous manner, the outlet connector 32 is glued in an intermediate cavity 36 formed between

  the upper end of the longitudinal section 20 and the ex-

  left end of cross section 26, shortened to

consequence (see Figure 1).

  When a thermostatic plate 10 is incorporated into an electrophoresis device, a layer of gel is applied to the upper face 18 of the plate

  upper glass 14, the material to be examined being

  troduite by the upper or lower end (Figure 1) of this gel layer, to be then routed to the other end considered of said layer, under

  the effect of a correspondingly oriented electric field

  laying. As a result, the direction of movement, illus-

  trée in Figure 1 by an arrow A, is oriented parallel-

  Lement to the longitudinal sections 20 and 22. To be able

  get routing tracks, straight and clear

  separated from each other, from different exchanges

  furrows that have been placed next to each other on the gel layer, at one longitudinal end of

  the latter, it is necessary that the temperature of the

  said layer be as constant as possible in a di-

  section B perpendicular to the direction of movement A (see Figure 1). For this purpose, the heat exchanger

  travels the internal space 28 along a sensitive path 38-

  zigzag or serpentine. Between the change of direction points, a trajectory. C is roughly parallel to direction B, therefore parallel to the direction of movement A. To maintain this path 38, the internal space 28 houses a series of guide strips 40, parallel to direction B and leaving alternately

  of the longitudinal section 20 and of the longitudinal section 22.

  The length of these guide strips 40 is less -

  at the interval between said longitudi-

  channels 20 and 22, thus giving rise to the desired route

38.

  The guide strips 40 consist of a metal

  conducts heat well, such as copper, to improve

9 2496266

  further improve the thermal constancy in direction B. Before the assembly of the thermostatic plate, all its constituents are cleaned thoroughly and thoroughly, for example in acetone; the metal guide strips 40 are subjected to an appropriate preliminary treatment, for example using a chemical adhesion agent manufactured by the company TEROSON, Heidelberg. Then, the spacer 16 in several parts is glued to one of the glass plates 12 and 14, thus

  as the fittings 30 and 32 and the guide bands 40.

  It should be noted that these organs should not be subjected to excessive compression, and that the

  excess glue must be removed. After hardening-

  ment of this glue, the other glass plate 14 or 12 is superimposed, then glued both to the spacer 16 and to the guide strips 40. The intermediate cavities 34 and 36 are filled around the connections 30 and 32,

  so that the internal space 28 is hermetically sealed-

  outward, apart from said connections 30 and

32.

  The glue used must have a large elas-

  ticity, good electrical insulation properties, resistance to water and buffer solutions,

  as well as good thermal conductivity, at temperatures

  erasures reaching up to 100 ° C. A silicone adhesive produced by the company TEROSON, Heidelberg, has been found suitable for this purpose. However, to adhere the guide strips 40 to the upper plate 14 (which is in contact with the gel layer), one can also use a two-component adhesive (sold, for example, by the company Henkel), because this adhesive presents a

  even better thermal conductivity.

  The external dimensions of the glass plates 12 and 14 are determined according to the dimensions of the gel layer used. For example, the glass plates 12 and 14 used have the following external dimensions: 200 mm x 200 mm, 280 mm x 355 mm, 200 mm x400mm! 0

and 300 mm x 900 mm.

  A thermostatic plate 10 of 200 mm x 400 mm

  has been successfully used in an electro-

  phoresis in which a voltage of 10,000 volts was applied to the gel layer. The medium heat exchanger

  was then induced by an individual heating device

  with thermostat (FRIGOMIX 1495, manufactured by the company

  Braun). The pressure difference between the inlet 30 and outlet 32 connections reached from 160 millibars to 240 millibars and the color power delivered by the plate 10 reached from 30 watts to 40 watts. During the preliminary electrophoresis, the calorific power can also reach up to 100 -iatts. Plate 10 was used at temperatures in the range of 5 C to 75 C. In this regard, it should be noted that the plate

  is not suddenly heated or cooled. For-

  dyeing, for example, an operating temperature of + 70 ° C. from room temperature, the plate 10 was firstly heated to 50 ° C. in three stages of 10 ° C. for a total duration of 15 minutes to 20 minutes, then at 70 C in four steps of 5 C, for a total duration

20 minutes.

  Since the plate 10 described above makes it possible to obtain good flatness of the upper face 18 applied against the gel layer, and very good thermal constancy in the direction of arrow B, therefore perpendicular to the direction of movement A, this plate 10 is particularly satisfactory in the presence of very thin gel layers (with a thickness of 0.02 mm to 1.5 mm), which allow the separation of biological macromolecules with high measurement accuracy. From

  particular measurement procedures, it is advisable to mention-

  especially the dissociation into DNA sequences, the electro-

  phoresis on SDS gel and isoelectric focusing.

  FIG. 3 illustrates a thermostatic plate produced according to a second embodiment. In this case, the organs which correspond to those of the figures

11 2496266

  1 and 2 are given the same reference numbers,

  increased by the number 100. In Figure 3, the top plate

  glass is not shown for the sake of simplicity

  Unlike the first embodiment according to Figures 1 and 2, fittings 130 and 132 are both arranged at the upper end of the plate.

  (observing figure 3), which facilitates the connection

  dement of said plate 110 to a device (not shown

  tee) supply of medium heat exchanger. In this case, the fittings 130 and 132 are bonded between one of the

  ends of a transverse section 126 shortened accordingly

  quence, and the corresponding ends of long sections

  120 and 122. To be able, in this embodiment also, to obtain a path 138 in a zigzag or

  serpentine necessary to ensure the desired distribution

  temperature gauge, an additional scale 150 is adjusted

  Tee tightly and glued between the two glass plates, in an internal space 128. This additional strip extends parallel to the longitudinal section 120, a short distance from the latter. Said strip 150

  part of cross section 12.6 and its length is less

  less than the interval between the two sections

  124 and 126. In this way, it is given birth

  sance, between the additional strip 150 and the longitudinal section 120, to a channel 152 which connects the fitting

  inlet 130 at the opposite end of the plate 110.

  From this area, the path 138 extends again

  zigzag or serpentine upwards, in the same way

  nier than in plate 10 illustrated in Figures 1

  and 2. This is again permitted by guide tapes.

  ge 140 which, in this case, are arranged in the zone between the longitudinal section 122 on the right (observing FIG. 3) and the additional strip 150, and which start alternately from said strip 150 and from said longitudinal section 122. Again , the length of the guide strips 140 is less than the space between the additional strip 150 and the longitudinal section 122. The material of which the additional strip 150 is made is first of all glass, so that the guide strips 140 have a constant temperature over their considered length; on the other hand, 140 different guide strips can

  have different temperatures.

  The thermostatic plates described above are characterized, among other things, by the fact that their manufacturing costs are low (about 10 to 20 times less than those of conventional plates); by the fact

  that they are particularly suitable for use

  read in a temperature range of around 700C (particularly suitable for dissociating DNA sequences); and by the fact that the thin glass plate 14 or 114 is directly in contact with the gel layer used, allowing better heat transmission and great thermal constancy, in particular in the direction perpendicular to the conveying direction. Because the glass plates are transparent, the gel layer can be

  lit and / or observed through these plates. An addi-

  tion of experimental material, as well as its path, can thus be easily observed. The plate 10 or 110 is easy to handle and, therefore, it can be optionally disassembled and reassembled several times, as

  a classic glass plate. Measurement can be performed

  killed horizontally or vertically.

  The heating of the gel layer necessary for carrying out the electrophoresis can, as is common in electrophoretic apparatuses of standard type, take place exclusively by a Joule effect,

  as a result of the current flowing through said gel layer. This-

  during, this can lead to an irreplaceable local distribution

  the temperature, from which a distortion may result.

  thermal sion of neighboring fractions of macromolecules, or even deterioration of the glass plates. Such damage is excluded when using thermostatic plates of the type described above. In the presence of the aforementioned thin layers of gel, with a thickness of

  0.02mm to 1.5mm, high voltages may be applied

  that these layers. The result is a shorter measurement time, improved resolution and better

  separation of the bands or fractions of macromolecules.

  It goes without saying that many modifications can be made to the thermostatic plate described.

  and shown, without departing from the scope of the invention.

14 2496266

Claims (14)

  1. Thermostatic plate fitted to a device   electrophoresis, in which a material to be examined travels   pour a flat layer of gel in one direction   located in the plane of said layer, and comprises   both a housing delimiting an internal space, as well as at least two fittings which, mounted on said housing and communicating with said internal space, allow the passage of heat exchanger means through said plate, plate characterized in that it comprises two flat glass plates (12,14; 112), parallel and distant from each other, as well as a spacer   (16; 116) which, interposed between said glass plates,   re (12,14; 112), along the respective peripheries of   these two plates (12,14; 112) and possibly including-   ment several parts, is connected, preferably glued, to these plates (12, 14; 112) and closes the internal space   (28; 128) formed between said plates (12, 14; 112).   2. Thermostatic plate according to claim 1, characterized in that the connections (30, 32;   130, 132) are arranged, preferably glued in the re-   spacer (16; 116), between the plates glass (12, 14; 112).   3. Thermostatic plate according to one of the res-   dications 1 and 2, characterized in that the glass plate (14) located closest to the gel layer has a thickness (b) of 1 mm to 4 mm, preferably 1.4 mm to 1.8 mm, optimally about 1.5 mm; and by the fact that the glass plate (12) remote from said gel layer has a thickness (a) of 2 mm   to 4 mm, optimal about 3 mm.   4. Thermostatic plate according to any one   of claims 1 to 3, characterized in that   the outer face (18) of the glass plate (14) located 2496266   closest to the layer repels the gel.   5. Thermostatic plate according to in particular one   of claims 1 to 4, characterized in that   the heat exchanger means traverses the internal space (28; 128) essentially in a direction (C) perpendicular to the direction of movement (A), the case   if necessary with one or more course changes.   6. Thermostatic plate according to claim, characterized in that the heat exchanger means traverses the internal space (28; 128) along   a path (38; 138) substantially in a zigzag.   7. Thermostatic plate, according to one of the res-   dications 5 and 6, characterized in that at least one guide strip (40; 140) perpendicular to the direction of movement (A) is arranged in the space internal (28; 128).   8. Thermostatic plate according to claim 7, characterized in that the guide strip (40; 140) is bonded to two glass plates (12,14; 112).   9. Thermostatic plate - according to one of the res-   dications 7 and 8, characterized in that the strip   guide (40; 140) consists of a thermo-material   conductor, preferably copper, aluminum or fine steel.   10. Thermostatic plate according to any one   of claims 1 to 9, characterized in that   the spacer (16; 116) essentially extends along   sides of a rectangle with long sections   tudinaux (20, 22; 120, 122) parallel to the direction of movement (A) and transverse sections (24,26   124, 126) connecting said longitudinal sections.   11. Thermostatic plate according to claim, characterized in that one of the connections (32 130) is located in the region of one end of one of the longitudinal sections (20; 120), the other connection (30 ; 132) being disposed near one end of 16 2496266   the other longitudinal section (22; 122), where appropriate in the vicinity of the respective contiguous end of one   transverse sections (26; 126).   12. Thermostatic plate according to the res-   dications 6 and 11, characterized in that the two connections (30, 32) are arranged in end zones of the longitudinal sections (22, 20) distant from each other in the direction of movement (A); speak   causes the guide strips (40) to have a long   less than the interval between said sections   120, 22); and by the fact that said ban-   guides (40) are distributed over the length of the   so-called longitudinal sections (20,22), starting alternately   of one <20) and the other (22) of these sections longitudinal.   13. Thermostatic plate according to claim 11, characterized in that the two connections (130, 132) are arranged in end zones of the longitudinal sections (120, 122) situated at the same height in the direction of movement (A); by the fact that, in the internal space (128), there is an additional strip (150) which, parallel to the direction of movement * nt (A) and located a short distance from one (120) of the sections   longitudinal, has a length less than the   tervalle separating the transverse sections (124, 126) and leaves from the transverse section (126) being closest to the connections (130, 132); by the fact that the bands   guide (140), inserted between said additional strip   (150) and the other longitudinal section (122), have   a length less than -the interval between the-   said additional strip <150) and the other long section   tudinal (122); and by the fact that said guide strips (140), distributed over the length of said additional strip (150), start alternately from the latter (150) and from said other longitudinal section (122).   14. Thermostatic plate according to any one   of claims 1 to 13, characterized in that it 17 2496266   is used for the electrophoresis of bio- macromolecules   logic, using a thin layer of gel, a thick   preferably up to 0.02 mm to 1.5 mm, applied   quée on one of the glass plates.