EP2647435B1 - System with a fluidic cell and a tempering element - Google Patents

Description

The invention relates to an arrangement of a flow cell and a temperature control element according to claim 1.

Microfluidic flow cells are used increasingly, in particular as disposable products, in analysis and diagnostics or in medicine for the conditioning of liquids before they are applied to the human body, and also for synthetic purposes.

While the function of a flow cell in the temperature control of a fluid can be exhausted, temperature control devices often only form components of flow cells with far more extensive functionality. The temperature control function is particularly important in flow cells for carrying out molecular genetic analyzes, including processes that amplify PCR or other nucleic acids, since the amplification reaction requires constant or changing reaction temperatures, typically between 30 ° C. and 95 ° C., which are above ambient temperature. The production of temperature-resistant flow cells with reproducible temperature control properties, which allow a particularly rapid and homogeneous temperature transition between an active temperature control element and the fluid to be temperature-controlled, in particular the production of such flow cells as inexpensive disposable products, poses considerable problems for production.

A flow cell with a temperature control device is from the US 6,613,560 B1 known. The flow cell is used to carry out the PCR process. A reaction chamber for the The PCR process also forms the temperature chamber. The temperature control chamber is delimited by a recess in a substrate and the thin, heat-transferring film mentioned at the outset, which covers the recess. A disadvantage of the temperature control process is the low thermal conductivity of plastics, which is why films with a small film thickness in the range of 50-200 µm are preferred. The manufacture, handling and assembly of such thin foils is very complex. Disadvantageously, the cover film does not form an exact plane due to its low mechanical rigidity. Likewise, thermal and mechanical influences during assembly of the film using adhesive or welding processes can easily lead to deformation of the film and thus to deviations from the plane in the range of a few 10-100 µm. This makes it more difficult to couple in heat by pressing on a temperature control element, with remaining air gaps in particular impairing the heat transfer and preventing a rapid balance between the temperature of the temperature control element and the temperature of the fluid in the temperature control chamber, in particular its uniform heating or cooling. Reproducible temperature control properties cannot be achieved, especially under the conditions of inexpensive mass production of this flow cell.

Arrangements of the type mentioned at the outset with a composite film having a metal layer emerge from the WO 02/01181 A2 , of the EP 1 878 497 A1 , of the EP 1 710 016 A2 , of the US 2010/311616 A1 , of the WO 2008/006617 A2 and the EP 1 878 495 A1 forth.

Flow cells with temperature chambers and temperature elements come from the US 2005/0153430 A1 and the WO 2008/157801 A2 forth.

Due to its high thermal conductivity, which is typically approx. 1000 times higher than that of plastic, the metal layer of the film also ensures rapid heat spreading laterally, ie parallel to the film plane. Even if a temperature control element is only partially in contact with the film, the film therefore assumes the temperature of the temperature control element sufficiently quickly and uniformly and transfers it further to the fluid. Production-related fluctuations in the size of the contact surface between the temperature control element and the film are negligible.

In a preferred embodiment of the invention, the plastic layer facing the fluid consists of a plastic compatible with the amplification reaction, preferably an olefin polymer such as PP, PE, COC or PC.

The at least one metal layer preferably comprises aluminum or a magnetizable metal, e.g. Nickel, on. In the latter case, the adhesion of a temperature control element to the film and thus the heat transfer between the temperature control element and the film can be improved by magnetic force.

The film layer of the composite film facing the temperature control element can also consist of a plastic, in particular the plastic from which the layer facing the fluid is also made. The layer facing the temperature control element expediently consists of a material which counteracts adhesive adhesion of the film to the temperature control element.

In the preferred embodiment of the invention, the thickness of the layers forming the film is in each case between 1 μm and 100 μm.

While it would be possible to produce the temperature control chamber exclusively from the thin composite film, for example by means of two film parts that are thermoformed, welded or glued in opposite directions, or a thermoformed film part is welded to a flat, undeformed film part, according to the invention the temperature control chamber is covered by a film that is covered with the composite film Recess is formed in a substrate, which is preferably produced using inexpensive injection molding, and the composite film is connected to the substrate, preferably welded or glued.

The film is preferably connected to a flat surface of the substrate bordering the recess.

The substrate can consist of the same plastic as the layer of the composite film facing the fluid and the entire temperature control chamber can thus be formed from only one material which is compatible with the fluids to be temperature-controlled.

According to the invention, the temperature control element has a fixed temperature control body that can be placed against the composite film for heat transfer.

According to the invention, the temperature control element can only be used in an edge area adjacent to the temperature control chamber, in which the composite film e.g. is connected to the surface of the substrate. The film is expediently supported in the edge region in such a way that the temperature control element can be applied to the film under high contact pressure. If the temperature control chamber is hermetically sealed during temperature control, the application of the temperature control element to only a part of the composite film forming the temperature control chamber has the advantage that a pressure build-up generated by heating and the associated expansion of the fluid in the chamber due to expansion of the composite film and thus accompanying increase in the volume of the temperature control chamber can be at least partially compensated for. The pressure build-up prevented in the temperature control chamber in turn reduces the valve requirements which may be necessary for a hermetic seal of the chamber.

In a further embodiment of the invention, devices for sucking the composite film onto the temperature control body can be formed. The thermal contact is improved by pressing the temperature control body against the film. If the composite film has a magnetizable metal layer, the temperature control body can be provided with a permanent magnet or electromagnet in order to improve the pressure of the temperature control body against the film by magnetic interaction.
In one embodiment of the invention, the composite film is deep-drawn while increasing its surface contacting the fluid.

The composite film can perform further functions within the flow cell, for example covering functions or a valve function.

It goes without saying that the flow cell with the temperature control chamber can have an inflow and outflow for the fluid, possibly for the flow of the fluid through the chamber during the temperature control. Likewise, the flow cell can also have channel structures, mixing and distribution elements for the fluids, liquid storage, reaction and detection chambers and the like elements which are customary in the prior art for carrying out analyzes and syntheses in microfluidic flow cells. The composite film expediently extends only over the partial area of the flow cell which contains the temperature control chamber in order to ensure that little or no heat flows into the other areas of the flow cell during the temperature control process.

Since the temperature control of a fluid in a temperature control chamber is always associated with a change in the volume of the fluid, it can be advantageous for the temperature control chamber to be hermetically sealed against adjacent channel and / or functional areas during the temperature control process. This may be necessary especially when heating up to close to the boiling point of the fluid. This prevents the fluid from leaving the temperature control chamber resulting from a change in volume and / or partial vapor formation. Due to the releasability of the closure, the fluid can be transported, processed or, e.g. in molecular genetic analyzes. To close it, it is advantageous to form a valve seat in the channel-shaped inflow and outflow of the temperature control chamber, the composite film not being firmly connected to the substrate in the region of the valve seat, but lying loosely and evenly on the substrate. The extensibility of the composite film allows a fluid to pass under pressure before or after the tempering process between the valve seat and the composite film and to be transported into or out of the chamber. During the temperature control, the inlet and outlet are hermetically sealed by pressing mechanical stamps of an external actuation device against the composite film lying on the substrate in the region of the valve seats.

The temperature control chamber according to the invention can also serve as a liquid store, for example to store a reagent in the flow cell before it is used. The volume of the stored reagent can be smaller than that of the tempering and storage chamber, so that the chamber, for example, before or with a fluid to be analyzed and mixed with the reagent completely or can be partially replenished. When the temperature control chamber is used as a storage chamber, a channel-shaped inflow and outflow of the temperature control chamber can advantageously be geometrically interrupted and the composite film can be firmly connected to the substrate in the interrupted channel area, for example by welding to form a sealing seam closing the channel. After opening the sealing seam, the fluids can be transported into and out of the chamber by means of pressure, and the closure points can then be used as valves. The metal layer in the composite film delimiting the storage chamber prevents liquid or gas from passing through the chamber wall during storage.

Fig. 1

einen Ausschnitt aus einer eine Temperierkammer aufweisenden Flusszelle,

Fig. 2

die Flusszelle von Fig. 1 mit einem angesetzten Temperierelement,

Fig. 3

die Flusszelle von Fig. 1 mit einem Ansaugkanäle aufweisenden Temperierelement,

Fig. 4

eine Flusszelle mit einer tiefgezogen Folie und ein Temperierelement,

Fig. 5

eine weitere Flusszelle mit einer tiefgezogenen Folie,

Fig. 6

eine Flusszelle mit einer in eine Ausnehmung in einem Substrat hinein durch Temperierelemente dehnbaren Folie,

Fig. 7

eine Flusszelle mit einer aus zwei dehnbaren Verbundfolien durch Auslenkung eines Temperierelements gebildeten Temperierkammer,

Fig. 8

eine Flusszelle mit einer aus zwei dehnbaren Verbundfolien gebildeten Temperierkammer mit Temperierelementen auf einander gegenüberliegenden Seiten,

Fig. 9

eine Flusszelle gemäß Fig. 1 mit einem ein Temperierfluid führenden Temperierelement,

Fig. 10

eine Flusszelle mit sich an eine Temperierkammer anschließenden Ventilbereichen, und

Fig. 11

eine Flusszelle mit einer als Speicherkammer dienenden Temperierkammer.

The invention is further explained below using exemplary embodiments and the accompanying drawings relating to these exemplary embodiments. Show it:

Fig. 1

a section of a flow cell having a temperature control chamber,

Fig. 2

the flow cell of Fig. 1 with an attached temperature control element,

Fig. 3

the flow cell of Fig. 1 with a temperature control element with suction channels,

Fig. 4

a flow cell with a thermoformed film and a temperature control element,

Fig. 5

another flow cell with a thermoformed film,

Fig. 6

a flow cell with a film which can be stretched into a recess in a substrate by means of temperature control elements,

Fig. 7

a flow cell with a temperature chamber formed from two stretchable composite films by deflecting a temperature control element,

Fig. 8

a flow cell with a temperature chamber formed from two stretchable composite films with temperature elements on opposite sides,

Fig. 9

a flow cell according to Fig. 1 with a temperature control element carrying a temperature control fluid,

Fig. 10

a flow cell with valve regions adjoining a temperature control chamber, and

Fig. 11

a flow cell with a tempering chamber serving as a storage chamber.

One in Fig. 1 Microfluidic flow cell shown in sections, which in the exemplary embodiment shown serves to carry out an amplification process, comprises a plate-shaped substrate 1 and a film 2 that is welded or glued to the substrate 1 in a fluid-tight manner.

A temperature-absorbing chamber 3 receiving a fluid is formed by a recess in the substrate 1 and the film 2, which covers this recess. The temperature control chamber 3 is connected via channels 4 and 5 to an inlet / outlet 6 and 7, respectively. It goes without saying that the temperature control chamber could deviate from or be connected to other chambers provided in the flow cell for other purposes.

In the exemplary embodiment shown, the film 2 consists of a composite of several layers, an inner layer 8 made of a plastic compatible with amplification reactions, a metal layer 9, in the example shown a layer of aluminum, and an outer layer 10 which, like the inner layer 8, consists of plastic . The inner layer 9 and the substrate 1 can be formed from the same material, which facilitates the fluid-tight welding of the film 2 to the substrate 1.

In the following Figures 2 to 6 For the sake of simplicity, the composite film 2 consisting of several layers is shown without the individual layers.

In order to bring a fluid located in the temperature control chamber 3 to a desired reaction temperature, which is required, for example, as part of the overall function of the flow cell, according to Fig. 2 a temperature control element 11 is placed on the wall of the temperature control chamber 3 formed by the film 2 and is kept at a temperature which corresponds to the desired temperature of the fluid in the temperature control chamber 3.

Depending on the desired fluid temperature, the temperature control element 11 can be a heating or cooling element. In the first case, heat is transferred from the temperature control element 11 to the fluid in the temperature control chamber 3, in the second case, conversely, heat flows from the fluid to the temperature control element 11.

As a result of the high flexibility of the thin film 2, the total layer thickness of which is in the range between 3 μm and 300 μm, the temperature control element 11 cannot lie flat against the film 2 in such a way that heat transfer is uniform over the entire contact surface. However, due to the high thermal conductivity of the metal layer 9 contained in the film 2, which is primarily able to conduct heat in the lateral direction parallel to the film plane, there is a rapid heat exchange between the temperature control element 11 and the fluid in the temperature control chamber 3, whereby uniform heating of the fluid whose temperature matches the temperature of the temperature control element 11.

It goes without saying that the fluid can stand still in the temperature control chamber 3 during the temperature control or can flow through the temperature control chamber 3 at a speed that allows temperature compensation.

An in Fig. 3 The temperature control element 11a shown has suction channels 12 through which a negative pressure which pulls the film 2a against the temperature control element 11a can be generated, so that there is a uniform heat transfer between the temperature control element 11a and the film 2a over the contact surface.

In the following figures, parts that are the same or have the same function are designated with the same reference number as in the previous figures, the relevant reference number being accompanied by the letters a, b, etc.

At one in Fig. 4 In the embodiment shown, a temperature control chamber 3b is essentially formed by a cap-like or chamber-like deformation 13 of a composite film 2b. An annular temperature control element 11b bears around the deformation 13 against the film 2b connected to a substrate 1b. The support of the film 2b by the substrate 1b permits an increased pressing force of the temperature control element 11b against the film 2b. Heat therefore transfers more evenly and is laterally conducted quickly through the metal layer contained in the film 2b into the center, so that temperature compensation between a fluid contained in the temperature control chamber 3b and the temperature control element 11b can take place in a short time.

Also an in Fig. 5 Embodiment shown used as the embodiment of Fig. 4 , an annular temperature control element 11c. A temperature chamber 3c is, as in the embodiments of 1 to 3 , formed by a recess in a substrate 1c. A composite film 2c covering the recess has a deformation 14 in the region of the recess, which increases the surface of the film 2c adjacent to the fluid while increasing the heat transfer performance, so that compared to the exemplary embodiment of FIG Fig. 4 an even faster adjustment of the temperature of the fluid in the temperature control chamber 3c to the temperature of the temperature control element 11c results.

Fig. 6 shows an embodiment with a film 2d, which in an area in which it forms a wall of a temperature control chamber 3d, is expandable by a temperature control element 11d into a recess forming the temperature control chamber 3d in a substrate 1d. A stop 15 on the bottom of the temperature control chamber 3d limits the expansion. In the in Fig. 1 shown expansion state, the temperature control element 11d lies evenly against the elastically or plastically stretchable film 2d, so that there is a uniform heat transfer and temperature exchange between the temperature control element and the fluid over the entire contact surface.

An arrangement of the temperature control element 11d and further temperature control elements 11d 'and 11d "can be shifted according to arrow 16, so that one of the temperature control elements 11d, 11d', 11d" can be extended according to arrow 17 by stretching the film 2d up to the stop 15. The fluid can then be successively tempered differently according to temperatures T1, T2 and T3 of the temperature control elements 11d, 11d ', 11d ".

An in Fig. 7 The exemplary embodiment shown for a flow cell comprises a substrate 24 that is welded or glued to an arrangement of composite films 2e and 2e '.

In addition to an area in front of a through-opening 25 in the substrate 24 and an environment adjacent to this area, the composite films 2e, 2e 'are also connected to one another by welding or gluing.

A temperature control element 11e which can be moved in the through opening 25 according to arrow 17e can the composite films 2e, 2e 'in the in Fig. 7 shown manner to form a temperature chamber 3e between the composite films 2e, 2e '. In the exemplary embodiment shown, both composite films 2e, 2e 'are like those in FIG Fig. 1 shown film formed with a metal layer. Deviating from the shown In the exemplary embodiment, only the film 2e facing the temperature control element 11e could be designed as such a composite film.

Inlets or outflows opening into the temperature control chamber 3e are in Fig. 7 Not shown.

Out Fig. 8 shows an embodiment of a flow cell with a temperature control chamber 3f. The temperature control chamber 3f is formed from two composite foils 2f and 2f 'welded or glued together. While the composite film 2f is flat, the composite film 2f 'has a deformation 13f formed by deep drawing and is also connected to inlets / outlets 6f, 7f.

A temperature control element 11f which is movable according to arrow 17f is opposite two temperature control elements 26 and 27 which can be moved in the opposite direction and which can be attached to the composite film 2f '. While the temperature control element 11f covers the entire side of the temperature control chamber 3f facing it and adjacent areas, the temperature control elements 26, 27 only bear against areas adjacent to the temperature control chamber 3f. Accordingly, heat is conducted laterally into the temperature control chamber. The free area formed by the deep-drawn deformation 13f can expand when the pressure in the temperature control chamber 3f builds up, partially compensating for the pressure.

Fig. 9 shows an embodiment of a flow cell with a substrate 1g and a film 2g and a temperature control chamber 3g that the flow cell of Fig. 1 corresponds.

In the exemplary embodiment shown, however, a temperature control element 11g is not formed by a fixed temperature control body, as in the previous exemplary embodiments, but rather comprises a chamber 18 arranged symmetrically to the temperature control chamber 3g for receiving a temperature-regulating fluid. The chamber 18 is located in a recess in a substrate 19 which is connected to the composite film 2g in the same way as the substrate 1g. The chamber 18 receives a fluid maintained at a certain temperature, which in the exemplary embodiment shown enters the chamber 18 via an inlet 20 and a channel 21 and flows out via a channel 22 and an outlet 23. In the exemplary embodiment shown, the substrate 1g and the substrate 19 consist of the same material. An inner layer 8g of the film 2g is also similar in material to the outer layer 10g facing the substrate 19.

One in Fig. 10 flow cell shown differs from the flow cell of Fig. 1 in that a valve with an actuator element 28 and 29 is provided in channels 4h and 5h, which are connected to a temperature control chamber 3h. The respective actuator element presses a composite film 2h in the closed state of the valve against a valve seat 30 or 31.

A temperature control element 11 h has a recess 32 in the middle of its temperature control surface that can be placed against the film 2 h, into which the composite film 2 h can expand during temperature control with increasing internal pressure in the temperature control chamber 3 h.

The actuators 28, 29 can be connected in one piece to the temperature control element 11h and can be moved together with it.

Fig. 11 shows a flow cell with a chamber 3i, which initially serves as a storage chamber for a reagent 33. At predetermined breaking points at 34 and 35, openings can be formed which allow access to the reagent 33 and the further use of the chamber 3i as a temperature control chamber.

Claims (12)

1. Arrangement comprising a flow cell and a temperature-control element, with a temperature-control chamber (3), which receives a fluid to be controlled in its temperature and the boundary wall of which is formed at least partially by a thin film (2) transmitting heat between the temperature-control element (11) and the fluid, the film being formed as a composite film (2) comprising multiple interconnected layers (8, 10), the layer (8) facing the fluid being a layer of plastic, at least one further layer (9) consisting of a metal, the temperature-control chamber (3) being formed by a recess in a substrate (1) covered with the composite film (2) and the composite film (2) being connected to the substrate,
   characterized
   in that the composite film (2a) can be drawn against the temperature-control element (11a) by suction channels (12) formed in the temperature-control element (11a) or in that the temperature-control element (11, 11b, 11c) only lies against the composite film (2, 2b, 2c) in a peripheral region that is adjacent to the recess in the substrate (1, 1b, 1c) and in which the composite film (2, 2b, 2c) is connected to the surface of the substrate (1, 1b, 1c).
2. Arrangement according to Claim 1,
   characterized
   in that the layer of plastic (8) facing the fluid consists of a plastic compatible with an amplification reaction, preferably an olefin polymer, such as PP, PE, COC or PC.
3. Arrangement according to Claim 1 or 2,
   characterized
   in that the at least one metal layer consists of aluminium or a magnetizable metal, for example nickel.
4. Arrangement according to one of Claims 1 to 3,
   characterized
   in that the film layer (10) facing the temperature-control element (11) consists of a plastic, in particular the same plastic as the layer (8) facing the fluid.
5. Arrangement according to one of Claims 1 to 4,
   characterized
   in that the respective layer thickness lies between 1 µm and 100 µm.
6. Arrangement according to one of Claims 1 to 5,
   characterized
   in that the composite film (2) is welded or adhesively bonded to the substrate (1).
7. Arrangement according to one of claims 1 to 6,
   characterized
   in that the temperature-control chamber (3h) can be closed by at least one valve, and in particular a valve seat (30, 31), against which the composite film (2h) loosely lies, is formed in a channel (4h, 5h), which is connected to the temperature-control chamber (3h), and which is covered by the composite film (2h) .
8. Arrangement according to Claim 6 or 7,
   characterized
   in that the substrate (1) consists of the same plastic as the layer (8) of the composite film (2) facing the fluid.
9. Arrangement according to one of Claims 1 to 8,
   characterized
   in that the temperature-control chamber (3i) can be used as a storage chamber and is formed with at least one closure, closing the storage chamber, as a predetermined breaking point (34, 35) for forming an opening.
10. Arrangement according to one of Claims 1 to 9,
    characterized
    in that the composite film (2c) is thermoformed to enlarge its surface adjacent to the fluid.
11. Arrangement according to one of Claims 1 to 10,
    characterized
    in that, in addition to the heat transmission, as a further function the composite film (2) within the flow cell is given at least one covering function and/or valve function.
12. Arrangement according to one of Claims 1 to 11,
    characterized
    in that the flow cell has an inflow and an outflow (6, 7) for the fluid, for the through-flow through the temperature-control chamber during the temperature control.

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