EP2042237A1

EP2042237A1 - Reactor system including reaction chambers and method for filling and emptying the reaction chambers

Info

Publication number: EP2042237A1
Application number: EP07117469A
Authority: EP
Inventors: designation of the inventor has not yet been filed The
Original assignee: Koninklijke Philips Electronics NV
Current assignee: Koninklijke Philips NV
Priority date: 2007-09-28
Filing date: 2007-09-28
Publication date: 2009-04-01
Also published as: WO2009040743A3; WO2009040743A2

Abstract

A reactor system (100) for carrying out a reaction comprises a central chamber (200) for storing reactants (210) required for carrying out a reaction, reaction chambers (300) for receiving the reactants (210) from the central chamber (200), a flexible foil (230, 330) forming a wall on at least one side of the central chamber (200) and on at least one side of the reaction chambers (300), fluidic channels (500) connecting the central chamber (200) and the reaction chambers (300), and a valve (400) for opening and closing the fluidic channels (500). The invention also relates to a method for filling and emptying the reactor chambers (300)

Description

FIELD OF THE INVENTION

This invention relates to a reactor system, in particular to a reactor system including one or more reaction chambers and also relates to a method for filling and emptying the reaction chambers, in particular to a method for filling the reaction chambers before onset of a reaction and emptying the reaction chambers after completion of the reaction, more in particular to a method for filling and emptying the reaction chambers before and after a polymerase chain reaction.

BACKGROUND OF THE INVENTION

Since an initial invention of a polymerase chain reaction (PCR) process in the year 1983 by Mullis, amplification using the PCR process has become a mainstream application, widely used in today's biochemical laboratories. The PCR process is used for the amplification of specific DNA fragments. Although the biochemical basics have been known since 1983, the PCR only was adopted for routine use after the invention of automatic thermo cyclers.
Thermocyclers available today allow many PCR reactions to run in parallel. However, all the reactions have to use an identical thermoprofile with identical number of total cycles. Samples are typically contained in reaction chambers which reside in holes in a thermal block. In order to fill or empty the reaction chamber, typically a pipetting step is necessary. Since the PCR process amplifies DNA material, any DNA inhibition in the reaction chamber may lead to false conclusions from analysis. The inhibiting material (could be a reactant left out from previous PCR) in the tube, if present, upon contact with ambient air, may lead to an insufficient amplification factor per cycle, which makes correct amplification impossible. This can lead to false conclusions (false negatives). Hence it is necessary to empty the tube completely and thouroughly.
US 6403037-B1 discloses a reaction vessel and temperature control system for performing heat-exchanging chemical reactions, such as nucleic acid amplification. The vessel has a body defining a reaction chamber, and a loading structure extending from the body for loading a sample into the chamber. The loading structure has a loading reservoir, an aspiration port, and respective fluid channels connecting the loading reservoir and aspiration port to the chamber. To load the sample into the vessel, the sample is first dispensed into the loading reservoir and then drawn into the chamber by application of a vacuum to the aspiration port. The vessel also includes a seal aperture extending over the outer ends of the loading reservoir and aspiration port. A plug is inserted into the aperture after loading the sample into the chamber to simultaneously seal the chamber, loading reservoir, and aspiration port from the external environment. The temperature of the sample is controlled by opposing plates positioned to contact opposite sides of the vessel. The system also includes thermal elements for heating or cooling the plates and optics for detecting one or more analytes in the sample. This system needs special pipettes for filling the chamber. Moreover, the pressure in the chamber is kept under control by either adding extra gas into the loading reservoir or reducing the volume of the loading reservoir without letting the air out. This results in fluidic flow during the heating and cooling cycles in and out of the reaction well through the filling and aspiration port.
It is an object of the invention to provide a reactor system including one or more reaction chambers which does not have the above-mentioned limitations and to develop a method for filling and emptying the reaction chambers.
Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not merely as explicitly set out in the claims.

BRIEF SUMMARY OF THE INVENTION

According to a first aspect, the invention provides a reactor system for carrying out a reaction wherein the reactor system comprises a central chamber for storing reactants required for carrying out a reaction; reaction chambers for receiving the reactants from the central chamber; a flexible foil forming a wall on at least one side of the central chamber and on at least one side of the reaction chambers;fluidic channels connecting the central chamber and the reaction chambers; and a valve for opening and closing the fluidic channels.
The invention provides a reactor system for executing several independent reactions in physically separated reaction chambers. The flexible foil which forms a wall on at least one side of the central chamber and on at least one side of the reaction chamber allows manipulation of inside pressure for enabling the transportation of the reactants into and out of the reaction chambers without having any additional components. Thus the reaction chambers do not have to be opened for filling or emptying. The valve closes the reaction chambers and prevents backing-mixing of the reactants during the reaction.
According to an embodiment of the invention, the reaction chambers have a flat geometry. The flat geometry is a geometry without any protrusions. The reaction chambers are preferably round in shape. The flat geometry ensures a proper connection with other parts of the reactor system..
According to yet another embodiment of the invention, the reaction chambers have rigid walls, wherein the rigid walls are configured to allow the flexible foil to form a wall on at least one side of the reaction chambers. The rigid walls allow easy approach of the flexible foil and eliminate the possibility of dead volumes in the reaction chambers. The rigid walls determine the reaction chamber volume.
According to a second aspect, the invention relates to a method for filling at least one reaction chamber of a reactor system, wherein the reaction chamber is configured for carrying out a reaction. The method comprises

i. opening a valve that is configured for controlling a fluid flow through fluidic channels, wherein the fluidic channels are arranged for enabling fluid flow between the reaction chambers and a central chamber, and wherein the central chamber is provided with a port and is configured for storing reactants required for carrying out the reaction;
ii. applying a pressure on the reaction chambers for forcing air out of the reaction chambers, wherein the forced out air is arranged to escape through the port provided on the central chamber;
iii. closing the valve;
iv. removing the applied pressure;
v. opening the valve;
vi. applying a pressure on the central chamber for forcing the reactants from the central chamber to the reaction chambers through the fluidic channels; and
vii. closing the valve after the reaction chambers are filled with the reactants.

The valve controlling the fluid flow between the central chamber and the reaction chambers via the fluidic channels is opened to begin the process of filling the reaction chambers. When the pressure is applied on the reaction chambers (step ii), the air contained in them is expelled out. This air is bubbled through the reactants and occupies the empty space above the reactants in the central chamber if the central chamber is pre-filled with reactants. In an alternative embodiment, the air escapes to the ambient environment through a port provided on the central chamber. Any air is preferably removed from the reaction chambers to eliminate any possible contamination of reactants with the air. When pressure is applied on the central chamber, the contents of this chamber, usually the reactants, are pressed into the reaction chambers via the fluidic channels leaving the air behind in the central chamber. Thus the reaction chambers are filled with the reactants by manipulating them externally. This ensures that the chambers need not be opened for filling. This method of filling eliminates a manual step otherwise required and prevents/reduces evaporation losses during a reaction.
According to a preferred embodiment of the invention, the reaction chambers comprise a flexible foil which forms at least one flexible wall. The reaction chambers have relatively rigid walls and are closed by a flexible foil either on top or bottom of the reaction chamber. The flexible foil forms a flexible wall and allows expansion or contraction of the reactants during the course of the reaction. The flexible foil is supported by supporting elements which are also flexible and allow the resulting motion of the foil due to expansion or contraction of the reactants.
According to another embodiment of the invention, the air of the reaction chambers is forced out by applying pressure on the flexible wall. An external force is applied on the wall of the reaction chamber that is formed by the flexible foil. This allows manipulation of inside pressure of the reaction chamber which further enables forcing of air out of the reaction chambers without opening the reaction chambers. This feature eliminates a possibility of contamination of the reactants with air during the reaction.
According to a further embodiment of the invention, the central chamber comprises at least one flexible wall. The flexible wall allows external manipulation of the pressure inside the central chamber and enables transportation of the reactants to the reaction chambers without any additional components.
According to a still further embodiment of the invention, the reactants of the central chamber are forced out by applying pressure on the flexible wall.
According to a highly preferred embodiment of the invention, the reaction is a polymerase chain reaction. Amplification of specific DNA fragments using polymerase chain reaction (PCR) process is widely used in many biochemical labs. The polymerase chain reaction is used for in-vitro-diagnostics and allows simultaneous measurement of multiple analytes from a single patient sample.The polymerase chain reaction provides optimized reproducible amplification conditions. Quick amplification allows rapid diagnostics. This reduces the trun-around time of the analytical instruments that require PCR amplification. Due to the integration and possible automation, untrained personnel can operate these instruments. The PCR process can be used for diagnostics, for homeland security and for research and forensic applications.
According to another aspect, the invention provides a method for emptying reaction chambers of a reactor system , wherein the reaction chamber is configured for carrying out a reaction, preferably after the reaction has been completed or at a point at which intermediate results need to be determined, comprises:

i. opening a valve configured for controlling fluid flow through fluidic channels, wherein the fluidic channels are arranged for enabling fluid flow between the reaction chambers and a central chamber, and wherein the central chamber is provided with a port and is configured to receive used reactants from the reaction chambers; and
ii. applying a pressure on the reaction chambers for forcing the used reactants out of the reaction chambers into the central chamber through the fluidic channels.

The described method of emptying ensures that the reaction chambers are thoroughly emptied. This method for emptying the reaction chambers is generally applicable for an automated sample processing equipment.
According to an embodiment of the invention, the reaction chambers comprise a flexible foil which forms at least one flexible wall.
Although the invention is particularly suitable for a device with multiple reaction chambers, it is also suitable for use in a system comprising one reaction chamber.
According to another embodiment of the invention, the used reactants of the reaction chambers are forced out by applying pressure on the flexible wall of these chambers.
According to a further embodiment of the invention, the reaction is a polymerase chain reaction.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.
Fig. 1a shows a reactor system before onset of a chemical reaction;
Fig. 1b shows a cross sectional view of the reactor system of Fig.1a;
Fig. 2a shows a reactor system wherein the air is forced out of a reaction chamber;
Fig. 2b shows a cross sectional view of the reactor system of Fig.2a;
Fig. 3a shows a reactor system, wherein the reaction chamber is being filled with reactants;
Fig. 3b shows a cross sectional view of the reaction system of Fig.3a;
Fig. 4a shows a reactor system wherein the reactants are forced out of a reaction chamber;
Fig. 4b shows a cross sectional view of the reactor system of Fig.4a;
Fig. 5 shows a reactor system containing ten reaction chambers; and
Fig. 6 shows an exploded view of the reactor system of Fig.5.

DETAILED DESCRIPTION OF THE INVENTION

Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not merely as explicitly set out in the claims.
The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. Any reference signs in the claims shall not be construed as limiting the scope. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. Where the term "comprising" is used in the present description and claims, it does not exclude other elements or steps. Where an indefinite or definite article is used when referring to a singular noun e.g. "a" or "an", "the", this includes a plural of that noun unless something else is specifically stated.
Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.
Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.
The term reaction in the context of invention may refer to an interaction between elements to form a new substance, a physical change in state of a substance, an amplification reaction or a chemical reaction.
As shown in Fig.1a, the reactor system 100 includes a central chamber 200. For clarity only one reaction chamber 300 is shown. A fluidic channel 500 connects the central chamber 200 and the reaction chamber 300. A valve 400 opens and closes the connection between the central chamber 200 and the reaction chamber 300. The central chamber is provided with a port 205. The central chamber 200 is in this specific embodiment partly filled with reactants 210. The rest of the central chamber is occupied by air 220. The reaction chamber also initially contains air 220. The valve 400 is closed.
The central chamber 200 preferably has a flexible top foil 230 whereas the reaction chamber 300 preferably has a flexible bottom foil 330 as shown in Fig. 1b. The reaction chamber 300 has rigid walls 340. Heating elements 600 and an insulator 700 are also shown in Fig. 1b. The insulator 700 has an inflatable foil 730.
A step of forcing air out of the reaction chamber 300 is illustrated in Fig. 2a and Fig. 2b. The reaction chamber 300 is clamped between the heating elements 600 and the insulator 700 by bringing the insulator 700 upwards by applying a force F on the insulator. A pressure P₁ is applied underneath the inflatable foil 730 to force out the air 220 from the reaction chamber 300 into the central chamber 200. The valve 400 is opened. The forced out air 220 bubbles through the reactants 210 present in the central chamber 200 if the central chamber is pre-filled as shown in this embodiment. The central chamber 200 expands to accommodate the air 220 coming out of the reaction chamber 300 by pushing the flexible foil 230 of the central chamber 200 upwards as is shown in Fig.2b.
A step of filling the reaction chamber 300 with the reactants 210 is shown in Fig. 3a and 3b. The pressure P₁ is removed underneath the inflatable foil 730 and a pressure P₂ is applied on the flexible top foil 230 of the central chamber 200 and the reactants 210 are forced into the reaction chamber 300. The valve 400 is opened.
A step of emptying the reaction chamber 300 off the reactants 210 is shown in Fig. 4a and Fig. 4b. The reaction chamber 300 remains clamped between the heating elements 600 and the insulator 700. The pressure P₁ is applied underneath the inflatable foil 730 to force out the used reactants 220 from the reaction chamber 300 into the central chamber 200. The valve 400 is opened.
Fig.5 shows a reactor system with ten reaction chambers. Fig. 6 shows an exploded view of the reactor system 100, showing the rigid part enclosing the reaction chambers 300, fluidic channels 500 and the central chamber 200. Foils 330 are used to enclose all the reaction chambers and the fluidic channels 500.
The step of forcing air 220 out of the reaction chamber 300 is explained in detail refering to Fig. 2a and Fig. 2b. The air 220 from the reaction chamber 300 is forced out by bringing the insulator 700 upwards by applying a force F until the reaction chamber 300 is clamped between the heating elements 600 and the insulator 700. The heating elements 600 heat the reactants 210 of the reaction chamber 300 to a desired temperature. The insulator 700 ensures that the heat is not lost to the atmosphere. This further ensures uniform temperature throughout the reaction chamber without any hot or cold spots. The central chamber 200 can either be pre-filled with the reactants 210 or can be filled with the reactants 210 after the air 220 is expelled out of the reaction chamber 300 if the reactants are highly viscous. Pressure P₁ which is greater than atmospheric pressure is applied under the insulator foil 730 and the valve 400 is opened enabling the connection between the central chamber 200 and the reaction chamber 300 through the fluidic channels 500. The air 220 is pressed out of the reaction chamber 300 into the central chamber 200 through the fluidic channels 500. The air 220 in the reaction chamber 300 is forced out by applying the pressure P₁ on the inflatable foil 730 above the insulator 700. Then the valve 400 is closed.
Preferably the central chamber 200 is pre-filled with the reactants 210 before starting the reaction if the reactants 210 are not very viscous. If the reactants 210 are very viscous, the air 220 may find it difficult to bubble through. In such a case, the central chamber 200 is filled only after the air 220 is expelled out of the reaction chamber 300. The central chamber 200 is filled with the reactants 210 through the port 205.
The reaction chamber 300 is filled with the reactants 210 as explained here with reference to Fig. 3a and Fig. 3b. The pressure P₁ is removed underneath the insulator foil 730 while maintaining the force F upwards to hold the reaction chamber 300 in between the heating elements 600 and the insulator 700. The valve 400 then is opened and the pressure P₂ is applied on the flexible top foil 230 of the central chamber 200. As a result, the reactants 210 are pressed into the reaction chamber 300 via the fluidic channels 500. Each reaction chamber 300 has one fluidic channel 500. In order to keep the insulator 700 in place, the upward force F on the insulator 700 needs to be larger than the projected reactant volume of the reaction chamber 300 multiplied by the pressure exerted by the reactants 210. The valve 400 is closed after all the reaction chambers 300 are filled. Volume of the reaction chamber 300 is determined by the geometry of the reaction chamber 300.
After the reaction chamber 300 is filled with the reactants 210, the reaction takes place. During the course of the reaction, the pressure P₁ is applied under the insulator foil 730. The force F upwards is still present. This maintains a controlled pressure on the reactants 210 and keeps the reaction chamber 300 pressed to the heating elements 600. The air under the insulator foil 730 gives compliance to the reaction chamber 300 and ensures a good contact with the heating element 600. During the reaction, expansion of the reactants is compensated by the air buffer under the insulator foil 730. The air under the insulator foil 730 works as an insulator during the reaction and it elimiates use of an extra insulator.
If the reaction carried out is a polymerase chain reaction, many thermal cycles have to be applied to the reactants. During this thermal cycling, the reactants inside the reaction chamber 300 may expand and contract. In order to ensure a good thermal contact between the reaction chamber 300 and the heating elements 600 throughout all the thermal cycles, the expansion or contraction of the reactants needs to be compensated. The concept of compensation is based on the rigid, static side 340 of the reaction chamber 300 which is in contact with the heating elements 600. The reaction chamber 300 is pressed upwards to the heating elements 600 by a force F. This force is exerted by a spring or pressure loaded support element (not shown). Every reaction chamber 300 has its own support element in order to ensure good thermal contact of all the individual reaction chambers 300 and the heating elements, Any play between them is eliminated. Since the reaction chambers 300 are closed by the flexible foil 330 on at least one side, expansion or contraction of the reactants 210 can take place. The supporting elements (not shown) of the flexible foil which are also flexible allow the resulting motion of the flexible foil, without losing preload of the reaction chamber 300 to the heating and cooling elements 600.
A step of emptying the reaction chambers after the completion of the reaction is explained here refering to Fig.4a and Fig.4b. After the reaction is completed and the reactants are cooled down, the valve 400 is opened. The pressure P₁ is applied underneath the insulator foil 730 and the used reactants 210 contained in the reaction chamber 300 are forced out into the central chamber 200. The valve 400 is closed.
It is to be understood that although preferred embodiments, specific constructions and configurations have been discussed herein for the device according to the present invention, various changes or modifications in form and detail may be made without departing from the scope and spirit of this invention.

Claims

A reactor system (100) for carrying out a reaction comprising:
i. a central chamber (200) for storing reactants (210) required for carrying out a chemical reaction;

ii. reaction chambers (300) for receiving the reactants (210) from the central chamber (200);

iii. a flexible foil (230, 330)forming a wall on at least one side of the central chamber (200) and on at least one side of the reaction chambers (300);

iv. fluidic channels (500) connecting the central chamber (200) and the reaction chambers (300); and

v. a valve (400) for opening and closing the fluidic channels (500).
The reactor system (100) of claim 1, wherein the reaction chambers (300) have a flat geometry.
The reactor system (100) of claim 1, wherein the reaction chambers (300) have rigid walls (340), and wherein the rigid walls (340) are configured to allow the flexible foil (330) to form a wall on at least one side of the reaction chambers (300).
A method for filling reaction chambers (300) of a reactor system (100), wherein the reaction chambers (300) are configured for carrying out a reaction comprising:
i. Opening a valve (400) that is configured for controlling a fluid flow through fluidic channels (500), wherein the fluidic channels (500) are arranged for enabling fluid flow between the reaction chambers (300) and a central chamber (200), and wherein the central chamber (200) is provided with a port (205) and is configured for storing reactants (210) required for carrying out the reaction;

ii. applying a pressure on the reaction chambers (300) for forcing air (220) out of the reaction chambers (300), wherein the forced out air (220) is arranged to escape through the port (205)provided on the central chamber (200);

iii. closing the valve (400);

iv. removing the applied pressure;

v. opening the valve (400);

vi. applying a pressure on the central chamber (200) for forcing the reactants (210) from the central chamber (200) to the reaction chambers (300) through the fluidic channels (500); and

vii. closing the valve (400)after the reaction chambers (300) are filled with the reactants (210).
The method of claim 4, wherein the reaction chambers (300)comprise a flexible foil (330) which forms at least one flexible wall.
The method of claim 5, wherein the air (220)of the reaction chambers (300) is forced out by applying the pressure on the flexible wall.
The method of claim 4, wherein the central chamber (200) comprises a flexible foil which forms at least one flexible wall.
The method of claim 7, wherein the reactants (210) of the central chamber (200) are forced out by applying pressure on the flexible wall.
The method of claim 4, wherein the reaction is a polymerase chain reaction.
A method for emptying reaction chambers (300) of a reacting device (100), wherein the reaction chambers (300) are configured for carrying out a reaction, and wherein the reaction has been completed, comprising:
i. opening a valve (400) configured for controlling fluid flow through fluidic channels (500), wherein the fluidic channels (500) are arranged for enabling fluid flow between the reaction chambers (300) and a central chamber (200), and wherein the central chamber (200) is provided with a port (205) and is configured to receive used reactants (210) from the reaction chambers (300); and

ii. applying a pressure on the reaction chambers (300) for forcing the used reactants (210) out of the reaction chambers (300) into the central chamber (200) through the fluidic channels (500).
The method of claim 10, wherein the reaction chambers (300) comprise a flexible foil which forms at least one flexible wall.
The method of claim 11, wherein the used reactants (210) of the reaction chambers (300) are forced out by applying pressure on the flexible wall.
The method of claim 10, wherein the reaction is a polymerase chain reaction.