Microfluidic processing chamber, test carrier and associated method for processing a liquid in a test carrier

Abstract

Microfluidic processing chamber (1) with at least one inlet (2) and at least one outlet (3), characterized in that - that a capillary check valve (4) is formed in the processing chamber (1) between the at least one inlet (2) and the at least one outlet (3), - wherein the check valve (4) is arranged in the processing chamber (1), - wherein the check valve (4) divides the processing chamber (1) into an inlet sub-chamber (5) connected to the inlet (2) and an outlet sub-chamber (6) connected to the outlet (3) and - thus preventing backflow from the outflow chamber (6) into the inflow chamber (5).

Description

[0001] The invention relates to a microfluidic processing chamber with at least one inlet and at least one outlet, as well as an associated test carrier.

[0002] The invention further relates to a method for processing a liquid sample in a test carrier of a centrifugal microfluidic platform, wherein the test carrier has a processing chamber with at least one inlet and at least one outlet.

[0003] Microfluidic processing chambers, as described above, are known and are used, for example, in centrifugal microfluidic platforms to perform individual process steps on a liquid sample under investigation. For this purpose, centrifugal microfluidic platforms typically feature a disposable plastic test carrier, often in the form of a disc, in which the chamber is formed.

[0004] In such systems, often referred to as "lab-on-a-disc," the test carrier is placed in a processing unit, which rotates the test carrier and thus the chamber. This allows individual process steps within the test carrier, and therefore also within the chamber, to be controlled by centrifugation. In particular, centrifugation can be used to pump liquids through the inlet into the chamber.

[0005] In such systems, a common task is to mix two liquids in the processing chamber and then convey the resulting mixture out of the chamber with as little residue as possible, in order to deliver it to downstream structures on the test substrate, for example, for optical analysis. Mixing the liquids in the processing chamber can be achieved by shaking the test substrate or by centrifugation with variable angular acceleration.

[0006] It is often desirable to switch from centrifugal to pressure-driven liquid conveying after mixing. For this purpose, pressure connections can be provided on the test carrier, allowing the conveying pressure to be supplied within the carrier. An advantage of this is that pressure-driven conveying can occur with the test carrier stationary, enabling optical analysis of the liquid using stationary light sources and optical sensors. In processing chambers known from the prior art, the transition from centrifugal to pressure-driven liquid conveying is only unsatisfactorily resolved. Typical problems arising during this transition include the formation of air bubbles in the liquid volume or in the liquid flow conveyed from the chamber, or the retention of significant liquid residues within the chamber.

[0007] Furthermore, if the chamber has multiple inlets, pressure differences can occur in the individual supply lines to the inlets when the chamber is pressurized. In this case, the supply lines are not isobarically connected to the chamber. As a result, some of the liquid volume can be undesirably pumped back into the supply lines instead of exiting the chamber through the outlet as intended.

[0008] DE 10 2013 218 978 B3 relates to a device and a method that allow conclusions to be drawn about the viscosity of a sample by determining the viscosity of liquids in a centrifuge tube. The device has a plurality of chambers, each connected to the others via fluid channels. The sample can be transported between individual chambers against fluid resistances by rotating a fluid module at different speeds, thereby generating a centrifugal force. A fluid resistance arranged between two chambers in a fluid channel can, for example, be designed as a capillary valve.

[0009] DE 10 2012 202 775 A1 relates to a fluidics module that is rotatable about a center of rotation. It has a first chamber, a second chamber, and a compression chamber, the chambers being connected to each other via fluid channels. To create a higher flow resistance within a fluid channel, an unspecified valve can be arranged in the fluid channel of the device.

[0010] DE 11 2005 001 985 T5 relates to a device for analyzing blood plasma components, which has a layered substrate comprising a blood inlet opening, a guide channel connected to the opening for directing the whole blood sample, a flow channel for separating blood cells and plasma, and a guide channel for the plasma. The aim is to separate blood cells and blood plasma from each other by using centrifugal forces.

[0011] EP 1 874 674 B1 also describes a valve arranged in a fluid channel.

[0012] From DE 10 2016 207 845 A1 a device is also known which uses a valve arranged in a fluidic connecting channel to control a fluid flow from an inlet chamber through the connecting channel into an outlet chamber in a fluid-dynamic manner.

[0013] Against this background, the invention aims to improve the control over the position and shape of a liquid volume in a microfluidic processing chamber as described above to such an extent that the problems known from the prior art can be avoided when transitioning from centrifugal to pressure-driven liquid conveying. The objective of the invention is therefore to achieve controlled, bubble-free, and virtually residue-free conveying of a liquid, in particular a mixture, as a continuous volume from a processing chamber through an outlet without conveying any liquid in the supply lines to the chamber. According to the invention, this is intended to increase, in particular, the reliability of processing a liquid sample under investigation in a test carrier of a centrifugal microfluidic platform.

[0014] To solve this problem, the features of claim 1 are provided according to the invention for a microfluidic processing chamber. In particular, it is thus proposed according to the invention to solve the problem in a microfluidic processing chamber of the type mentioned at the outset that a capillary check valve is formed in the processing chamber between the at least one inlet and the at least one outlet.

[0015] In other words, the invention provides for the formation of a capillary pressure barrier in the processing chamber between the at least one inlet and the at least one outlet. According to the invention, the pressure barrier serves to limit the spread of a liquid, particularly when the processing chamber is stationary, especially when caused by gravitational or surface forces. This makes it possible to control the position and shape of a liquid volume in the processing chamber, particularly when the processing chamber is stationary.

[0016] A processing chamber according to the invention, having the features of claim 1, can, for example, be configured on a test carrier as described above and used together with a processing device of a centrifugal microfluidic platform. With this approach, precisely defined volumes of different liquids can be automatically combined in the processing chamber, mixed together there, and then, by applying a conveying pressure to the chamber, conveyed almost residue-free to subsequent structures in the test carrier, for example, to perform an analysis of the liquid mixture.

[0017] The inventive design of the processing chamber allows for the combined use of both centrifugation for combining and mixing the liquids and pressure-driven conveying of the liquid through subsequent capillary channels, since the transition between the two conveying methods can be controlled. Crucially, the inventive processing chamber, with the features of claim 1, creates a stable holding position for the liquid volume (as will be explained in more detail below). From this holding position, the liquid volume can be conveyed from the processing chamber through the outlet in a controlled manner, free of air bubbles and with virtually no residue, particularly under pressure while the test specimen is stationary. The inventive check valve prevents, in particular, the unintentional conveyance of liquid into the supply lines to the processing chamber.

[0018] The capillary check valve / pressure barrier can be designed in a known manner by changing the chamber cross-section, in particular by changing the chamber height and / or width, and / or by changing the wetting properties of the chamber's inner wall. A change in wetting properties can be achieved, for example, by applying a coating or by surface treatment.

[0019] According to the invention, for example, the capillary check valve can be formed by a change in the cross-sectional area of ​​a chamber. In this case, the cross-sectional area of ​​the chamber at the location of the check valve can have a width-to-height ratio of 5:1 or 10:1 or even greater.

[0020] According to the invention, at the location of the capillary check valve or pressure barrier, the capillary pressure increases, preferably abruptly, due to a changing chamber geometry or changing wetting properties of the chamber's inner wall. The check valve is designed, according to the invention, such that in a static state, for example after centrifugation, a liquid or liquid mixture located in the processing chamber cannot overcome the pressure barrier due to gravitational or surface forces, particularly in a radially inward direction with respect to a center of rotation used during centrifugation.

[0021] According to the invention, for a controlled transition from centrifugal to pressure-driven conveying, it is advantageous to create a situation in which the entire liquid volume in the processing chamber is located radially outward with respect to the capillary check valve in a stable waiting position in the form of a single, continuous droplet. Such a stable waiting position can be achieved according to the invention by centrifugally collecting the liquid volume in a sub-section of the processing chamber connected to the outlet, hereinafter referred to as the discharge sub-chamber. For this purpose, the liquid or a mixture formed in the chamber is centrifuged at such a high angular velocity that the entire liquid volume passes through the capillary check valve in a radial direction outward.

[0022] According to the invention, the processing chamber can also have more than one inlet. This can be advantageous, for example, if the processing chamber is configured such that a first inlet serves to introduce a liquid sample, for example, one obtained from a swab, and a second inlet serves to vent the processing chamber, for example, during the filling of the processing chamber with the liquid sample. In addition, the second inlet or a further inlet can be configured to introduce another liquid into the chamber. Alternatively, two liquids can be introduced into the chamber via a common inlet for controlled mixing. According to the invention, a separate air inlet can be provided for pressurizing the chamber, or one of the inlets already described can be configured for this purpose.According to the invention, the separate air inlet can also be connected to supply lines for introducing liquids, for example to enable venting of the chamber.

[0023] According to the invention, the problem can also be solved by further advantageous embodiments of the dependent claims.

[0024] In an advantageous embodiment, the check valve can be designed to divide the processing chamber into an inlet chamber connected to the inlet and an outlet chamber connected to the outlet, thus preventing capillary backflow from the outlet chamber into the inlet chamber.

[0025] This design makes it possible to bring a liquid volume, ideally smaller than the volume of the discharge chamber, into a defined holding position within the discharge chamber, from which pressure-driven conveying can then commence. Providing an inlet chamber separated from the rest of the processing chamber by a check valve has the advantage that inlets, especially pressure inlets, can be spatially separated from the liquid volume in the discharge chamber. Such separation avoids the problems known from the prior art when transitioning to pressure-driven conveying, as a well-defined air volume forms, spatially separating the liquid volume from the inlets.

[0026] A preferred embodiment of the invention provides that a siphon is connected to the outlet of the processing chamber. By providing a siphon at the outlet of the processing chamber, it is possible to prevent liquid from escaping through the outlet of the processing chamber during a mixing process, for example, one generated by centrifugation. According to the invention, the siphon can be designed, in particular, to have a reversal point from which the siphon extends radially inwards with respect to a center of rotation used during centrifugation. This causes a backflow of liquid in the siphon during centrifugation, which prevents the chamber from emptying. The siphon thus ensures that the liquid can only be conveyed through the outlet in a controlled manner at a later time by pressure-driven conveying, in order to supply it to subsequent process steps.

[0027] It can be particularly advantageous if the siphon is designed as a capillary. The benefit here is that during a centrifugal mixing process, only a small portion of the liquid volume to be mixed remains in the siphon, while the majority of the liquid volume participates in the mixing process in the processing chamber.

[0028] Another preferred embodiment of the invention provides that the outlet has a greater radial distance relative to a center of rotation used during centrifugation than the capillary check valve. This makes it possible to collect a volume of liquid by centrifugation in one or more of the drain chambers connected to the outlet, and then to convey it through the outlet as a single, continuous volume, free of air bubbles. For this purpose, it is particularly advantageous if the outlet is arranged at a radially outermost point of the chamber relative to a center of rotation used during centrifugation.

[0029] Similarly, it is advantageous if the inlet has a smaller radial distance relative to a center of rotation used during centrifugation than the capillary check valve. This allows the inlet chamber, or the chamber connected to it, to be completely emptied by centrifugation without any liquid collected in the outlet chamber being drawn into the inlet.

[0030] A further development of the invention provides that the processing chamber, preferably the discharge chamber, has at least one area designed for mixing liquids by shaking or centrifuging. It is clear to a person skilled in the art that mixing liquids in the processing chamber by shaking or centrifuging is only possible if the inertial forces generated by these movements in the liquid volume dominate over frictional forces and capillary forces prevailing in the chamber, such that a non-laminar flow can be generated in the liquid volume. This is equivalent to the requirement that a sufficiently high Reynolds number is achieved during shaking or centrifuging, as a prerequisite for turbulent flows in the liquid volume that allow for efficient mixing.A high Reynolds number can be ensured in particular by a sufficiently large chamber height, while efficient mixing may be unreliable or even impossible with very low chamber heights.

[0031] Furthermore, according to the invention, the volume of the processing chamber can be designed to be larger than the volume of liquid to be mixed. For efficient mixing, it is advantageous if an air bubble remains in the chamber during the mixing process, so that this additional volume can also be used during the mixing process.

[0032] For efficient mixing, it is therefore preferred according to the invention if the processing chamber, preferably the discharge chamber, has a section with a chamber height of more than 1 mm, in particular more than 1.5 mm. This allows very high Reynolds numbers to be achieved, so that turbulent flows can be used for mixing.

[0033] Furthermore, it is particularly advantageous if the processing chamber, preferably the discharge chamber, has a volume of at least 0.1 mL, preferably at least 0.3 mL, and most preferably at least 0.5 mL. This is because the invention recognizes that such large volumes are advantageous so that, on the one hand, a volume is available for subsequent analyses that allows the required statistical reliability of the analysis to be achieved, and on the other hand, the chamber only needs to be partially filled during the mixing process.

[0034] To ensure a high level of safety against contact between the liquid droplet in the waiting position and the inlets of the processing chamber, the invention provides that the inlet or inlets are arranged at a distance from the capillary check valve. It is particularly advantageous if this distance is at least 1 mm.

[0035] Further improvements in the handling of a liquid volume in the processing chamber can be achieved according to the invention by having the capillary check valve extend over the entire width of the chamber. This ensures that no liquid can unintentionally flow past the check valve.

[0036] To achieve a particularly robust valve function, it is further preferred according to the invention if the check valve has an edge. To utilize such an edge for retaining a fluid meniscus, it is advantageous if it is sharply defined and / or at least right-angled, preferably acute-angled. Thus, according to the invention, the edge can be formed in particular by a convex projection. This projection can form a right-angled or even acute-angled edge. Such a projection can be produced particularly easily, for example, by milling or hot stamping from a plastic body.

[0037] One embodiment of a processing chamber according to the invention provides that the height of the inlet chamber is greater than, in particular, the maximum height of, the outlet chamber. This embodiment allows for a particularly large total volume of the processing chamber to be made available for efficient mixing of liquids. At the same time, the outlet chamber can be dimensioned such that the formation of a continuous droplet in the waiting position is promoted by a lower chamber height.

[0038] Another embodiment of the invention provides that the chamber height of the inlet chamber is greater than, in particular the maximum, the chamber height in the area of ​​the check valve. This design allows a valve function to be implemented in a particularly simple manner.

[0039] Furthermore, according to the invention, the chamber height of the drain chamber can be greater than, in particular, the maximum chamber height in the area of ​​the check valve. This allows for a particularly robust design of the check valve, as it enables the formation of two spaced-apart edges on the check valve.

[0040] According to the invention, the processing chamber is designed for the transition from centrifugal to pressure-driven liquid conveying. For this purpose, it is particularly advantageous if the discharge chamber is designed to allow for residue-free emptying, especially under pressure. This is the case, for example, if dead spaces in the discharge chamber are omitted and / or the channel walls taper towards the outlet and / or are designed to support a droplet shape.

[0041] For a controlled transition from centrifugal to pressure-driven fluid conveying, the invention may, in particular, provide at least one pressurizable inlet and / or at least one vent outlet. The vent outlet may be formed by an inlet for introducing a liquid into the chamber. For the most efficient pressure-driven emptying of the chamber, it is advantageous according to the invention if the pressurizable inlet and the vent outlet open into the inlet chamber of the processing chamber and / or if the pressurizable inlet and the vent outlet are arranged radially inside the capillary breakthrough valve.

[0042] According to the invention, the following can also be provided for a further advantageous design of the processing chamber: - that the inlet chamber is wider than the outlet chamber; because this allows for particularly robust pinning of a fluid meniscus even at the edges of the check valve; - that the processing chamber is limited by a film and a structured plastic part; because this makes the processing chamber very easy to manufacture; - that the chamber height of the drainage chamber slopes radially outwards, in particular where the chamber height of the drainage chamber reaches a minimum in the area of ​​the outlet; because this design promotes residue-free emptying of the drainage chamber; - that the non-return valve is designed in such a way that it can only be breached by the liquid when the test carrier is rotating due to inertial forces.

[0043] The aforementioned problem can be solved particularly easily if a processing chamber according to the invention is designed in a test carrier and / or used in a centrifugal microfluidic platform. In particular, a test carrier according to the invention can be designed in the form of a disk.

[0044] According to the invention, the features of the independent method claim are further provided to solve the problem mentioned at the outset. In particular, the invention thus proposes a method of the type described at the outset to solve the problem, characterized by the following process steps: First process step: Centrifugal filling of the processing chamber with the liquid through the inlet; Second process step: Performing at least one processing operation on the at least one liquid in the processing chamber; Third process step: Centrifugal collection of the at least one liquid or mixture produced in the second process step in a discharge chamber of the processing chamber connected to the outlet; Fourth process step: Emptying the processing chamber by pressure-driven conveying of the at least one liquid or a mixture formed through the outlet with the test carrier stationary.

[0045] According to the invention, in the third process step, the liquid volume is conveyed into the previously described stable waiting position, from which the fourth process step can be reliably initiated by applying a conveying pressure to the processing chamber. The processing chamber thus serves, according to the invention, to carry out at least one processing step on at least one liquid. It can be provided that the liquid is held at a distance from the inlet between the third and fourth process steps. This allows the waiting position to be reached, in which unwanted backflow into the (possibly multi-channel) inlet after applying a conveying pressure can be prevented. This holding is preferably achieved microfluidically, for example with the aforementioned check valve and / or due to capillary forces in the processing chamber.For this purpose, it may be sufficient, for example, to choose a sufficiently small chamber height for the processing chamber so that capillary forces are dominant. It has been found that backflow to the inlet can be prevented if a liquid meniscus formed in the processing chamber develops sufficient retention force. Additionally or alternatively, the previously described check valve can also be used to advantage to prevent backflow.

[0046] A further development of this method according to the invention provides that in the first process step the processing chamber is filled centrifugally with at least two liquids and that the second process step is a mixing process. This describes a particularly robust method for the controlled conveyance of a liquid mixture from a processing chamber.

[0047] A further development of the methods discussed so far, according to the invention, provides that after emptying the processing chamber, at least one further processing step, in particular an optical analysis, is carried out on at least one liquid or on a mixture formed, preferably on the test carrier. According to the invention, a controlled, pressure-operated emptying of the processing chamber in the fourth processing step can thus be advantageously utilized for subsequent process steps.

[0048] A further embodiment of the methods discussed so far provides that the liquid is conveyed through a capillary check valve formed between the inlet and the outlet during the second and / or third process step. In this specific method, the entire volume of the processing chamber can thus be utilized for the processing in the second process step, with the liquid then being conveyed through the valve into the discharge chamber in the third process step.

[0049] Finally, in all the methods discussed so far, it can be provided according to the invention that in the fourth process step the chamber is pressurized via the inlet and / or emptied via a siphon at the outlet. This describes in more detail two particularly simple practical implementations of methods according to the invention.

[0050] According to the invention, it is further particularly advantageous if the processing chamber is only partially filled in the first process step, especially with a volume that is smaller than the volume of a discharge chamber connected to the outlet. This ensures that, in the third process step, an inlet chamber connected to the inlet can be completely emptied of liquid by centrifugation. This is advantageous for achieving the previously described stable waiting position of the liquid.

[0051] In summary, a possible use of a microfluidic processing chamber according to the invention, employing the inventive method, can be described as follows: In a first step, the processing chamber is filled with at least one liquid by, for example, centrifuging, conveying the liquid through an inlet into the chamber. Subsequently, further processing steps, such as a mixing step, can be carried out in the filled chamber. According to the invention, it can be provided, in particular, that a second liquid is conveyed into the chamber through another or the same inlet to be mixed with the at least one liquid. Mixing can be achieved, for example, by shaking or rotating at different speeds. The resulting mixture is then collected centrifugally in the discharge chamber.Centrifugal forces act on the liquid, sufficient to allow the mixture to pass through the check valve. The centrifugal force is then switched off, with the check valve reliably preventing the liquid from flowing back into the inlet chamber. Finally, pressure can be applied to the inlet(s) to force the liquid out of the outlet chamber. This process achieves virtually loss-free emptying of the processing chamber, making almost the entire volume of liquid collected in the outlet chamber available for subsequent analysis.

[0052] In all the methods discussed so far, it is particularly advantageous if a processing chamber or a test carrier according to the invention is used, in particular as described above or according to one of the claims directed to a processing chamber or a test carrier.

[0053] The invention will now be described in more detail with reference to exemplary embodiments, but is not limited to these embodiments. Further exemplary embodiments result from combining the features of one or more claims with each other and / or with one or more features of the respective exemplary embodiment. In particular, embodiments of the invention can thus be derived from the following description of a preferred exemplary embodiment in conjunction with the general description, the claims, and the drawings.

[0054] In the following description of various embodiments of the invention, elements that are functionally identical are given the same reference numbers even if they differ in design or shape.

[0055] It shows: Fig. 1 a lateral sectional view through a processing chamber according to the invention, Fig. 2 a lateral sectional view through a further processing chamber according to the invention, Fig. 3 a lateral sectional view of another possible embodiment of a processing chamber according to the invention, Fig. 4 a lateral sectional view of another possible embodiment of a processing chamber according to the invention, Fig. 5 a lateral sectional view of yet another embodiment of a processing chamber according to the invention, Fig. 6 a top view of a test carrier according to the invention which has a processing chamber according to the invention.

[0056] Fig. Figure 1 shows a microfluidic processing chamber, designated as 1 in its entirety. This chamber has an inlet 2 and an outlet 3. The inlet 2 opens into an inlet chamber 5, and the outlet 3 opens into a drain chamber 6. As indicated by the two arrows pointing radially outwards, it is preferred according to the invention if the drain chamber 6 is arranged radially outwards with respect to the inlet chamber 5. In this case, a liquid droplet 8, with which the processing chamber 1 has been filled, can be collected in the drain chamber 6 by centrifugation, as shown in Figure 1. Fig. 1 is indicated by the hatched area.

[0057] The outflow chamber 6 is designed to be microfluidic, in accordance with the invention. In particular, the cross-section of the outflow chamber 6 is selected such that capillary forces, which act, for example, between the chamber walls and the liquid, are dominant over gravitational forces acting on the liquid in this area. This makes it possible for the liquid volume designated 8 (indicated by hatched areas in all figures) to spread out towards the inlet 2, i.e., to the right, in a static state. Fig. 1. This prevents backflow of liquid from the outflow chamber 6 into the inflow chamber 5 and from there to the inlet 2.

[0058] According to the invention, as in Fig. It is also indicated that, for example, a capillary check valve 4 is provided at the location designated 4. This can, as Fig. Figure 1 shows that it is formed solely by a hydrophobic coating on the bottom of the chamber. At the location of the check valve 4, the local contact angle of the liquid and thus the capillary pressure changes abruptly, so that the liquid volume 8 is effectively retained. How Fig. As illustrated in Figure 1, the check valve 4 can thus, in particular, divide the processing chamber 1 into an inlet sub-chamber 5 and an outlet sub-chamber 6.

[0059] Even without surface coatings, a capillary check valve, as in Fig. 2 shows that this can be achieved by changing the chamber geometry. For this purpose, the following is shown in Fig. The processing chamber 1 shown in Figure 2 has a right-angled edge 9 that defines the location of the check valve 4. A fluid meniscus approaching this edge from the left is held against it and thus prevented from advancing further towards the inlet 2. According to the invention, the air-filled inlet chamber 5 thus creates a distance between the check valve 4 and the inlet 2. As well as in Fig. As can be seen in Figure 2, the inflow chamber 5 has a greater chamber height than the outflow chamber 6.

[0060] Fig. Figure 3 shows a further improvement of the capillary check valve 4 according to the invention. This is formed by a convex projection 10 on the chamber roof, which forms a sharp-edged or acute-angled edge 9. Compared to Fig. The sharper angle of edge 9 increases the retention of a fluid meniscus by the check valve 4. In addition, the chamber height at edge 9 is reduced compared to the chamber height of the drain chamber 6, which further enhances the retention of a fluid meniscus.

[0061] Mixing two liquids in processing chamber 1 can be achieved particularly efficiently if it has a large chamber height, as in Fig. 4 shown. Due to the resulting increase in hydrostatic pressure in the liquid, a particularly robust capillary check valve 4 must be used, for example formed by a pointed edge 9, as shown in Fig. 4 shown.

[0062] According to the invention, two mutually spaced edges 9 can also be formed on the check valve, as shown in Fig. 5 shown. This is shown in the Fig. The example shown in section 5 is made possible, among other things, by the fact that the drain chamber 6 has a chamber height that is greater than the chamber height in the area of ​​the check valve 4.

[0063] Fig. Figure 6 illustrates by way of example the arrangement according to the invention of a microfluidic processing chamber 1 in a disk-shaped test carrier 13. The test carrier 13 has a center of rotation 14 around which the test carrier 13, and thus the processing chamber 1, rotates during centrifugation. The capillary check valve 4, indicated by the dashed line and whose position is defined by an edge 9, extends over the entire width of the processing chamber 1.

[0064] Three inlets 2 open into the inflow chamber 5, each connected to a supply line 11. Further structures of the test carrier 13 connected to the supply lines, such as pressure connections or sample receiving chambers, are not shown. A siphon 7 is connected to the single outlet 3, towards which the outflow chamber 6 funnels, forming a drain 12. How well in Fig. As can be seen in Figure 6, the siphon 7 has a reversal point from which it extends radially inwards towards the center of rotation 14. If the liquid volume designated 8 is centrifuged in the drainage chamber 6, the liquid will continue to enter the siphon 7 until a radial fill level is reached in the siphon 7 that corresponds to that of the drainage chamber 6.

[0065] If one follows in Fig. By following a radius 6 from the center of rotation 14 towards the processing chamber 1, it can be seen that the inlet 2 is arranged radially inside with respect to the capillary check valve 4 and the outlet 3 is arranged radially outside with respect to the check valve 4. Thus, for example, the outlet 3 has a greater radial distance from the center of rotation 14 than the check valve 4. Furthermore, by following the radius, it also becomes apparent that the three inlets 2 are each arranged at a distance from the check valve 4 indicated by the dashed line.

[0066] The in Fig. Figure 6, an embodiment of a test carrier 13 according to the invention, shows in particular a shape of the processing chamber 1 that is advantageous for a controlled transition from centrifugal to pressure-driven liquid conveying. The lateral chamber walls of both the inlet and outlet chambers are each symmetrically aligned with a radius that passes through the center of rotation 14 and the outlet 3. In addition, the inlet chamber 5 has a greater width than the outlet chamber 6. It is also advantageous that the processing chamber 1 has no centrifugal undercuts. The combination of these features according to the invention facilitates the merging of separate droplets formed during mixing in the processing chamber 1 into a single, cohesive droplet in the outlet chamber 6 by means of centrifugation.

[0067] As shown by the Fig.As can be seen in Figure 6, when liquid is introduced into the processing chamber 1 through one of the supply lines 11, an adjacent supply line can serve to vent the processing chamber. After the liquid has been collected centrifugally in the drain chamber 6, the processing chamber 1 can be pressurized via one or, for example, all three inlets 3.

[0068] To prevent air bubble formation and residues when emptying a microfluidic chamber 1, it is proposed to divide the chamber 1 into an inlet chamber 5 and an outlet chamber 6 by means of a capillary check valve 4, designed, for example, by a change in the chamber geometry. This makes it possible to carry out a processing operation on a liquid in the entire chamber 1, to subsequently collect the liquid, for example, by centrifugation, in a continuous droplet in the outlet chamber 6, and finally to convey the liquid from a controlled waiting position, without it coming into contact with the chamber's inlets, through an outlet connected to the outlet chamber in a controlled and continuous flow, preferably pressure-driven, thus making it available for subsequent process steps.The microfluidic chamber 1 according to the invention and the associated method can therefore be used in particular for a controlled transition from centrifugal fluid conveying to pressure-driven fluid conveying. Reference symbol list 1 processing chamber 2 Entrance 3 Outlets 4 Check valve 5 Inflow sub-chamber 6 Drainage chamber 7 Siphon 8 fluid volume 9 edge 10 lead 11 Supply line 12th derivative 13 test subjects 14 Turning Center

Claims

[1] Microfluidic processing chamber (1) with at least one inlet (2) and at least one outlet (3), characterized by , - that a capillary check valve (4) is formed in the processing chamber (1) between the at least one inlet (2) and the at least one outlet (3), - wherein the check valve (4) is arranged in the processing chamber (1), - wherein the check valve (4) divides the processing chamber (1) into an inlet sub-chamber (5) connected to the inlet (2) and an outlet sub-chamber (6) connected to the outlet (3) and - thus preventing backflow from the outflow chamber (6) into the inflow chamber (5). [2] Processing chamber (1) according to the preceding claim, characterized by , that a capillary siphon (7) is connected to the outlet (3). [3] Processing chamber (1) according to any one of the preceding claims, characterized by, that the outlet (3) has a larger radial distance with respect to a center of rotation (14) used in centrifugation than the capillary check valve (4) and / or - that the inlet (2) has a smaller radial distance with respect to a center of rotation (14) used in centrifugation than the capillary check valve (4). [4] Processing chamber (1) according to any one of the preceding claims, characterized by , that the processing chamber (1) has at least one area suitable for mixing liquids by shaking or centrifuging. [5] Processing chamber (1) according to any one of the preceding claims, characterized by , that the processing chamber (1) has a volume of at least 0.1 mL and / or an area with a chamber height of more than 1 mm. [6] Processing chamber (1) according to any one of the preceding claims, characterized by, that the inlet (2) or inlets (2) are arranged at a distance from the capillary check valve. [7] Processing chamber (1) according to any one of the preceding claims, characterized by , that the capillary check valve (4) extends over the entire width of the chamber [8] Processing chamber (1) according to any one of the preceding claims, characterized by , that the check valve (4) has an edge (9) suitable for retaining a fluid meniscus. [9] Processing chamber (1) according to any one of the preceding claims, characterized by , that a chamber height of the inflow sub-chamber (5) is greater than a chamber height of the outflow sub-chamber (6) and / or than a chamber height in the area of ​​the check valve (4) and / or that a chamber height of the outflow sub-chamber (6) is greater than a chamber height in the area of ​​the check valve (4). [10] Test carrier (13) of a centrifugal microfluidic platform, characterized by , - that the test carrier (13) has a processing chamber (1) according to one of the preceding claims. [11] Method for processing a liquid in a test carrier (13) of a centrifugal microfluidic platform, - wherein the test carrier (13) has a processing chamber (1) according to one of claims 1 to 9, with at least one inlet (2) and at least one outlet (3), and - the procedure is characterized by the following procedural steps: 1) Centrifugal filling of the processing chamber (1) with the liquid through the inlet (2); 2) Carrying out at least one processing operation on the at least one liquid in the processing chamber (1); 3) Centrifugal collection of the at least one liquid or mixture produced in the second process step in a discharge chamber (6) of the processing chamber (1) connected to the outlet (3), - wherein the liquid or mixture is centrifuged at such a high angular velocity that an entire liquid volume (8) passes through a capillary check valve (4) in a radial direction outwards, and - wherein the liquid volume (8) in a static state is prevented from spreading towards the inlet (2) by the check valve (4); 4) Emptying the processing chamber (1) by pressure-driven conveying of the at least one liquid or a mixture produced through the outlet (3) with the test carrier stationary; [12] Method according to claim 11, characterized by that the liquid is kept at a distance from the inlet between the third and fourth process steps. [13] Method according to claim 11 or 12, characterized by, that in the first process step the processing chamber (1) is filled centrifugally with at least two liquids and that the second process step is a mixing process. [14] Method according to any one of claims 11 to 13, characterized by , that after emptying the processing chamber (1) at least one further processing process is carried out on the at least one liquid or on a mixture formed. [15] Method according to any one of claims 11 to 14, characterized by , that in the fourth step of the process the chamber is pressurized via the inlet (3) and / or emptied via a siphon (7) at the outlet (3).

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