WO2011007309A1

WO2011007309A1 - Fluid actuation system

Info

Publication number: WO2011007309A1
Application number: PCT/IB2010/053175
Authority: WO
Inventors: Reinhold Wimberger-Friedl
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2009-07-17
Filing date: 2010-07-12
Publication date: 2011-01-20

Abstract

The invention relates to a microfluidic system comprising: a microfluidic device (20) comprising: o a microfluidic circuit (28) for flowing a fluidic sample (25); and o an outer wall having a first opening (21 ) therethrough in communication with the microfluidic circuit (28); a receiving device (10) comprising: o an opened cavity (14) able to receive at least a part of the microfluidic device (20); o a chamber (12) comprising an inner volume and a wall having a second opening (11 ) therethrough in communication with the inner volume; a gas path (30) generated between the first and the second openings (1 1, 21 ) allowing a gas but not the fluidic sample (25) flowing between the microfluidic circuit (28) and the chamber (12), when the microfluidic device (20) is received into said cavity (14) at a determinate relative position; wherein the system is arranged such that the volume of the chamber is modified when the position of the microfluidic device (20) into the cavity (14) is beyond a threshold position.

Description

FLUID ACTUATION SYSTEM

FIELD OF THE INVENTION

The invention relates to a microfluidic system comprising:

- a microfluidic device with a microfluidic circuit for flowing a fluidic sample; and

a receiving device comprising an opened cavity able to receive at least a part of the microfluidic device for flowing the fluidic sample in the microfluidic circuit.

BACKGROUND OF THE INVENTION

Such a microfluidic system can be used in various applications, such as for example food or biological sample analysis (e.g. blood, saliva, urine) so as to manipulate and/or analyze and/or determine therein presence of elements (e.g. bacteria, proteins, biomarkers, DNA...). Such samples are typically collected and stored in said microfluidic device.

Once said receiving device (e.g. an analyzer) receives the microfluidic device, it is typically necessary to flow the sample in the microfluidic device through a microfluidic circuit for e.g. filtering, mixing with additional particles or components, incubating and/or driving purposes until a test chamber where the sample can be analyzed.

In order to flow the sample in the microfluidic device, it is known to provide in the microfluidic device some lateral flow surfaces (by providing e.g. a porous layer on the surfaces) and/or rigid capillary channels.

Nevertheless, these techniques are not efficient enough for some microfluidic devices, especially those comprising long fluidic paths.

In order to attempt to solve this problem, US 2008/0025872 discloses a microfluidic system in which the flow of the sample in a channel is regulated by a micro-pump or an actuator bulb in communication with the channel. Nevertheless, a micropump is costly, needs a battery and the action of the actuator bulb on the fluid motion cannot be controlled with accuracy.

SUMMARY OF THE INVENTION

In order to overcome the aforementioned drawbacks, the invention proposes, according to a first embodiment, a microfluidic system comprising: - a microfluidic device comprising:

o a microfluidic circuit for flowing a fluidic sample; and

o an outer wall having a first opening therethrough in communication with the microfluidic circuit;

- a receiving device comprising:

o an opened cavity able to receive at least a part of the microfluidic device; o a chamber comprising an inner volume and a wall having a second opening therethrough in communication with the inner volume; - a gas path generated between the first and the second openings allowing a gas but not the fluidic sample flowing between the microfluidic device and the chamber, when the microfluidic circuit is received into said cavity at a determinate relative position;

wherein the system is arranged such that the volume of the chamber is modified when the position of the microfluidic device into the cavity is beyond a threshold position.

By modifying the volume of the chamber, this system according to the invention generates a controlled underpressure or overpressure in the chamber and in the gas path that can be transferred to the microfluidic device (e.g. a cartridge) that may generate a flow of the sample in the microfluiic circuit.

This flow of sample in the microfluidic circuit can therefore be generated by the mere insertion of the cartridge into the receiving device by the operator, without need of extra controls or timing delays or other requirements for the user.

This under or overpressure is only determined by the modification of the volume of the chamber which is dependent of the relative position of the cartridge in the cavity (from the threshold position) and not by the speed of movement of the cartridge into the cavity. The control of sample flow in the microfluidic circuit is therefore more under control.

Additionally, the flow of the sample may also be controlled by capillary forces and/or lateral flows techniques.

Moreover, the microfluidic system is easy to use, since the coupling between the microfluidic device and the receiving device may be done easily and reversibly by simple engagement and disengagement of the microfluidic device.

Optional embodiments of the invention are as follows:

- The system is further arranged such that the gas path is opened when the position of the microfluidic device in the cavity of the receiving device is at or beyond an opening position. The gas path may be openable when the first opening faces an end part of the gas path. The opening position may be reached after the said threshold position, when inserting the microfluidic device into the cavity of the receiving device, the system being possibly arranged such that the volume of the chamber increases (creating therefore an underpressure within) when the microfluidic device is beyond the threshold position and that a gas located between the fluidic sample and the valve is vented into the volume of the chamber via the gas path when the microfluidic device is at or beyond the opening position: the sample is flowed accordingly in the microfluidic device.

- the gas path is openable by pressure difference of the gas contained on each side of the valve; for a determinate pressure applied on the valve by the gas at the first opening side, the valve is opened when the inner volume reaches a limit volume; this valve may improve the situation by allowing the vent to be operated once the underpressure in the chamber reaches a determinate value: this increases the control on the fluidic flow; in particular, a sealing interface may be created by sliding the microfluidic device in the cavity towards a stop position (e.g. by providing stop means at the bottom of the cavity of the receiving device). The displacement from the initiation of the sealing until the stop may create a stroke in a (de-)pressurizing means which concurrently with the insertion movement creates a pressure change in the microfluidic device from the sealing interface through the chamber and the gas path to a channel of said microfluidic circuit which is in fluid communication with the sample.

the chamber comprises a mobile wall limiting a side of the inner volume, arranged to be moved by the microfluidic device when the microfluidic device is beyond the threshold position; the mobile wall is mechanically connected to the microfluidic device when the microfluidic device is at and beyond the threshold position.

The under or overpressure created in the chamber is therefore only determined by the modification of the volume of the chamber which is dependent of the relative position of the cartridge in the cavity (from the threshold position) but not on the speed of movement of the microfluidic device into the cavity. The control of sample flow in the microfluidic circuit can therefore be controlled accurately.

- This flow of sample may be used for different purposes, e.g. filtering the sample, separating the sample in various sub-samples, allowing the sample to enter a storage chamber where some components are stored to be mixed with the sample and/or the sample to reach a test zone where an analyzer may analyze the sample. In a particular embodiment, the receiving device is an analyzer of at least one element in the sample: this single insertion of the microfluidic device may therefore also be used to position accurately the said test zone with respect to the detection means embedded in the receiving device. In particular, the microfluidic device may be arranged to contain a biological fluidic sample which can flow through the microfluidic circuit when the microfluidic device is at or beyond the opening position and the microfluidic system may be a biosensor, wherein the receiving device comprising detection means able to detect at least one analyte contained in the sample, after the sample is flowed through the microfluidic circuit;

According to a second embodiment, the invention proposes a fluid actuation device comprising

- an opened cavity for receiving a microfluidic device having a microfluidic circuit able to contain a fluidic sample;

a chamber comprising an inner volume and a wall having an opening therethrough in communication with the inner volume and comprising a mobile wall limiting partly the inner volume;

- a gas path extending between the opening and the cavity to allow a gas but not the fluidic sample flowing between the chamber and the microfluidic device, via another opening provided through an outer wall of the microfluidic device and communicating with the fluidic circuit;

actuator between the mobile wall and a bottom portion of the cavity such that the inner volume of the chamber is modified when the position of the microfluidic device into the cavity is beyond a threshold position from which the microfluidc device actuates the actuator.

Optional features of the second embodiment according to the invention are the following:

- the actuator comprises a U-shaped shaft;

This U-shaped configuration gives some freedom in the design of the receiving device, since the chamber can be located anywhere in the receiving chamber. This might be very useful to reduce the encumbrance / volume of the receiving device. Moreover, this can be very useful if some constraints exist for the design of the receiving device (e.g. placing some detection and/or manipulating means in the receiving device in order to test and/or manipulate the sample);

the chamber and the cavity are adjacent one to the other;

- the actuator further comprises an elastic member provided between the mobile wall and a fixed part of the device such that a restoring force is exerted onto the mobile wall towards an equilibrium position when the elastic member is strained;

- the chamber is cylindrical and the mobile wall is a piston;

stop member to stop the cartridge into the cavity at a stop position.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows a perspective view of a microfluidic system.

Figure 2 shows a longitudinal cross-sectional view of a microfluidic device of a microfluidic system according to a first embodiment of the invention.

Figure 3 shows a longitudinal cross-sectional view of a receiving device of a microfluidic system according to a first embodiment of the invention.

Figure 4 shows a longitudinal cross-sectional view of a microfluidic device of a microfluidic system according to a second embodiment of the invention.

Figure 5 shows a longitudinal cross-sectional view of a receiving device of a microfluidic system according to a second embodiment of the invention.

Figures 6A-6C shows schematically three steps of operating a microfluidic system according to the invention.

Figure 7 shows a longitudinal cross-sectional view of an alternative microfluidic system according to the second embodiment of the invention.

Figure 8 shows a longitudinal cross-sectional view of another alternative of a microfluidic system according to the second embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 depicts schematically an example of a microfluidic system comprising a microfluidic device or cartridge 20 and a receiving device 10 able to receive the cartridge 20 in an opened cavity 14. The cartridge 10 comprises microfluidic circuit (not shown in this figure) containing locally a fluid or liquid, which fluid is able to be flowed into the microfluidic circuit when the user inserts the cartridge 10 into the receiving device 10 from a determinate threshold position. In a particular embodiment, the receiving device 10 is also arranged to analyze and/or manipulate the fluid and may also comprise an analyzer (e.g. optical or magnetic detector) and/or means for manipulating the sample (e.g. magnetic actuator of magnetic particles contained in the sample) and processing and data storing means. In order to run the processing means, some user interface (screen, keypad,...) may also be provided in the receiving device 10. Optionally the cartridge 20 comprises means for receiving a biological sample (e.g. urine, saliva, blood) and flow it via the microfluidic circuit according to the invention, and possibly also according to other techniques (capillary channels and/or through lateral flow), to a detection zone where the detection means in the receiving device can test the sample.

Fig. 2-3 show respectively a cartridge 20 and a receiving device 10 of a microfluidic system according to a first embodiment of the invention, and Fig. 4-5 show respectively a cartridge 20 and a receiving device 10 of a microfluidic system according to a second embodiment of the invention.

Figures 2 and 4 depict longitudinal cross-sections of the cartridges 20 according to the respective two embodiments. For both embodiments, the cartridges 10 have a housing comprising an inner microfluidic circuit 28 opened to the outside of the cartridge 20 through an opening 21. This microfluidic channel may comprise at least one channel 23 extending between a storing part 22 where the sample 25 is stored and a receiving zone 24 where the sample 25 is supposed to be received once it is flowed through the channel 23 according to the invention. This receiving zone 24 may be the detection zone as aforementioned. The sample 25 stored in the storing part 22 may be prevented from flowing into the channel 23 thanks to a fluidic stop, a hydrophobic wall, a valve or any other means located at the outlet of the storing part 22. This storing part 22 may contain a porous material where the sample had been collected. The channel 23 may be any kind of channel. In particular, at least a part of this channel 23 may be designed as a capillary channel and/or a flow-through channel facilitating the displacement of the sample 25 into the microfluidic circuit 28. The person skilled in the art can easily understand that this very simple microfluidic circuit 28 is described in this description for illustration purposes only and that any other kind, even more

complicated (e.g. with several channels and other microfluidic elements) may be designed and adapted to the invention without any difficulty.

According to a first embodiment of the cartridge 10, and as depicted in Fig. 2, the opening 21 is located upstream and communicates with the storing part 22. The sample 25 may be prevented from flowing through the opening 21 thanks to a fluidic stop, a hydrophobic wall, a valve or any other means located at the entrance of the storing part 22 for stopping the fluid leaving out the storing part 22 through the opening 21.

Figure 3 depicts a longitudinal cross-section view of a receiving device 10 (or a portion of a receiving part 20) able to work with the cartridge 20 according to the first embodiment (i.e. of Fig. 2). This receiving device 10 has a housing comprising an opened cavity 14 arranged to receive the cartridge 20 through the inlet 15, and an inner gas chamber 1 1. The cavity 14 communicates, via a gas path 30, to the chamber 12 through an opening 1 1 provided in the housing of the receiving device 10. The gas path 30 is arranged such that the gas can circulate within but not a liquid. This can be obtained by providing a fluidic stop at the interface with the opening 21 and/or providing a gas filter in the gas path 30. Alternatively, the said microfluidic device 20 may comprise means to prevent the fluid going into the gas path 30. The receiving device 10 is arranged such that the volume of the chamber 12 is decreased when the cartridge 20 is pushed into the cavity 14. This volume reduction may be caused by any kind of technique, e.g. by using mechanical means as depicted in Fig. 3: a mobile wall 13 of the chamber 12 is pushed by the cartridge 20 (either directly or via an

intermediate means such as for example a shaft, a liquid or a spring). The volume decrease may be caused by any other means (e.g. electrical, magnetic, liquid pressure) triggered by the cartridge 20 when the cartridge 20 overpasses a threshold position with respect to the receiving device 10. The reduction of the volume of the gas in the chamber 12 creates an overpressure within which is transmitted to the microfluidic circuit 28 via the gas path 30 which pushes the sample 25 out of the storing part 22 into the channel 23 until the receiving zone 24. Optionally, a stop 13a is provided, e.g. in the chamber 12, to limit the motion of the mobile wall 13: this stop 13a allows to control the pressure generated in the chamber 12.

According to a second embodiment of the cartridge 10, and as depicted in Fig. 4, the opening 21 of the cartridge 20 is located downstream the storing part 22 and communicates with the channel 23.

Figure 5 depicts a longitudinal cross-section view of a receiving device 10 (or a portion of the receiving device 10) able to work with the cartridge 20 according to the second embodiment (i.e. of Fig. 4). This receiving device 10 has a housing comprising an opened cavity 14 arranged to receive the cartridge 20 through the inlet 15, and an inner gas chamber 11. The cavity 14 communicates, via a gas path 30, to the chamber 12 through an opening 11 provided in the housing of the receiving device 10. The gas path 30 is arranged so as to leave the gas circulating within but not the fluid 25. This can be obtained by providing a fluidic stop at the interface with the opening 21 and/or providing a gas filter in the gas path 30. Alternatively, the said microfluidic device 20 may comprise means to prevent the fluid going into the gas path 30. The receiving device 10 is arranged such that the volume of the gas in the chamber 12 is increased when the cartridge 20 is pushed into the cavity 14. This volume increasing may be caused by any kind of technique, e.g. by using mechanical means as depicted in Fig. 5: a mobile wall 13 of the chamber 12 is pulled by the cartridge 20 via an intermediate means extending from the bottom of the cavity 14 to the wall 13, such as for example a shaft, a spring, a liquid in a channel; in this specific illustration, it is used a U-shaped shaft 16 allowing to locate the chamber 12 adjacent the cavity 14 and reducing accordingly the length of the receiving device 10; the mobile wall 13 acts like a piston in an inner cavity 17 (e.g. o cylindrical shape) of the receiving device 10, splitting the inner cavity 17 into the chamber 12 and a secondary chamber 18. The volume increase may be caused by any other means (e.g. electrical, magnetic, liquid pressure) triggered by the cartridge 20 when the cartridge 20 overpasses a threshold position with respect to the receiving device 10. The increasing of the volume of the chamber 12 creates an underpressure within which is transmitted to the microfluidic circuit 28 via the gas path 30 which pulls the sample 25 out of the storing part 22 into the channel 23 until the receiving zone 24. Optionally, a stop 13a is provided, e.g. in the chamber 12, to limit the motion of the mobile wall 13: this stop 13a allows to control the pressure generated in the chamber 12.

Fig. 7 and 8 depicts respectively two other particular microfluidic systems according to said second embodiment. An elastic means 19 (e.g. a spring or an elastic material) is provided in the secondary chamber 18 of the inner cavity 17. Optionally, a stop 13a is provided at the bottom of the cavity 14 so as to control the motion of the cartridge 20 into the cavity 14 by stopping it at a stop position, therefore the motion of the mobile wall 13, accordingly the pressure generated in the chamber 12, and so the fluidic flow in the cartridge 20. The gas path 30 may be a channel (Fig 7) or a mere interface (Fig. 8) between the opening 1 1 and the opening 21. A valve 31 may be provided in the gas path 30 which can be opened by a latch in the cartridge such that a connection is established which is vacuum-tight.

This valve 31 may be provided in any microfluidic system according to the invention (e.g. those of FIG 1-8), in the gas path 30 and/or in the cartridge 20 close to the opening 21 and/or in the receiving device 10 close to the opening 1 1. This valve 31 may be a lid opened by mechanical means (a latch or cantilever) which is actuated by moving the cartridge 20 over the opening position. This gives design freedom and in particular the possibility to have the valve 31 placed further removed from the cartridge 20, since the volume of the gas path 30 can be made very small. The valve 31 might be an elastomeric membrane which is moved by a pin actuated by the movement of the cartridge 20. Alternatively or in combination, the substrate sides of the cartridge 20 can act as a seal against the gas path 30 in the chamber 12 as it slides over the cavity 14, and the communication between the chamber 12 and the microfluidic circuit 28 can be tightly established when the cartridge 20 reaches an opening position. Tightness may be achieved by having smooth and soft surfaces and applying a slight normal force from the sliding mechanism of the cartridge 20 inside the cavity 14 of the receiving device 10. A joint may also be provided on the sides of the cartridge 20 and/or on the inner surfaces of the cavity 14, such that the joint is placed around the interface between the opening 21 and the gas path 30 when the microfluidic system is assembled. The said opening position corresponds to a position in which the volume of the chamber 12 changes such that the pressure can lead to a fluidic flow of the sample 25 in the microfluidic circuit 28 of the cartridge 20.

As a third alternative, the mobile wall 13 (or piston) can act as a seal for the opening in the chamber 12 if the opening 11 of the chamber 12 is located on the edge of the mobile wall 13 before the opening position (not shown). In particular a joint can be provided on the periphery of the mobile wall 13.

The operating method is illustrated by Fig.θA to 6C with the particular system embodiment of Fig. 8.

A general principle of the invention is that a mechanism is integrated in the microfluidic system which is activated when the cartridge 20 is inserted into the cavity 14 of the receiving device 10 by the operator. The force of the operator is used to store energy in the system which is used to drive the fluidics (i.e. sample 25) in the cartridge 20 in a mere and operator independent way.

The cartridge 20 needs to be pushed inside the cavity 14 of the system until it hits a stop 13a where it is arrested (FIG6A-6B. The last part of that movement is coupled to the shaft 16 which is pushed by the cartridge 20 against a spring force 19 (FIG.ΘA). The shaft 16 is attached to the mobile wall (or piston) 13 inside the inner cavity 17 (e.g. a cylinder). The displacement of the piston 13 creates underpressure inside the chamber 12 as long as it is closed (Fig 6B).

The pressure is only determined by the position of the piston 13 and not by the speed of movement.

The piston 13 moves synchronous to the cartridge 20. When a certain position (an "opening position") is reached by the cartridge 20, a connection is established between the chamber 12 and the opening (or vent) 21 of the channel 23 (not shown in Figs. 6). This opening position can correspond to the stop position of the cartridge 20 when it abuts onto the stop 13a (Fig. 6B).

The connection can be achieved in several ways. The cartridge substrate surface can act as seal against an opening in the cylinder 17, or alternatively a valve 31 can be opened by a latch in the cartridge 20 such that a connection is established which is vacuum-tight, or as a third alternative the piston 13 can act as seal for the opening in the cylinder. As soon as the piston 13 moves past that opening the volume inside the cylinder is connected to the cartridge.

The pressure difference between the chamber 12 and the channel 23 of the cartridge 20 will actuate the fluid 25 inside the cartridge 20.

The cartridge 20 can be prefilled to a certain extent by capillary force, e.g. until a blood filter or a hydrophobic stop. The pressure difference will drive the fluids with a certain rate which may be desirable to carry out a biological assay.

This pressure difference can be precisely controlled by the alignment of the drive shaft 16 and can be chosen in a wide range, depending on the mechanical design of the system. Friction force does not play a role since the piston 13 is not moving during actuation of the flow as it is solely determined by the position of the cartridge 20 which is abutted onto the stop 13a. To ensure the position of the cartridge 20 with respect to the receiving device 20, it can be provided locking means to lock the cartridge 20 into the cavity 14.

At the end of the analysis the operator can remove the cartridge 20 by sliding it back (Fig 6C). In this way the system is restored in the original state and pressure can be equilibrated with the ambient atmosphere.

It is preferable that the cartridge 20 design assures that no sample liquid 25 is spilled out of the cartridge 20 into the vacuum channel. This may be achieved by some appropriate design of vent and waste chamber, known from the person skilled in the art.

The chamber 12 (or inner cavity 17) and shaft 16 can be placed below, above or next to the cartridge 20 depending on space requirements of other interfaces, in particular the sensor unit (e.g. optics or magnets) that may be arranged in the receiving device 10 if the latter is an analyzer.

Any reference sign in the following claims should not be construed as limiting the claim. It will be obvious that the use of the verb "to comprise" and its conjugations does not exclude the presence of any other elements besides those defined in any claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

Claims

1. Microfluidic system comprising:

a microfluidic device (20) comprising:

o a microfluidic circuit (28) for flowing a fluidic sample (25); and

o an outer wall having a first opening (21 ) therethrough in communication with the microfluidic circuit (28);

a receiving device (10) comprising:

o an opened cavity (14) able to receive at least a part of the microfluidic device (20);

o a chamber (12) comprising an inner volume and a wall having a second opening (11 ) therethrough in communication with the inner volume;

a gas path (30) generated between the first and the second openings (1 1 , 21 ) allowing a gas but not the fluidic sample (25) flowing between the microfluidic circuit (28) and the chamber (12), when the microfluidic device (20) is received into said cavity (14) at a determinate relative position;

wherein the system is arranged such that the volume of the chamber is modified when the position of the microfluidic device (20) into the cavity (14) is beyond a threshold position.

2. Microfluidic device according to claim 1 , wherein the system is further arranged such that the gas path (30) is opened in a tightly manner when the position of the microfluidic device (20) in the cavity (14) of the receiving device (10) is at or beyond an opening position.

3. Microfluidic device according to claim 2, wherein the gas path (30) is openable when the first opening (11 ) faces an end part of the gas path (30).

4. Microfluidic device according to one of claims 1 to 3, wherein it comprises a valve (31 ) which opens the gas path (30) by pressure difference of the gas contained on each side of the valve (31 ).

5. Microfluidic device according to claim 4, wherein, for a determinate pressure applied onto the valve (31 ) by the gas at the first opening (21 ) side, the valve (31 ) is opened when the inner volume reaches a limit volume.

6. Microfluidic system according to claim 2, wherein the threshold position is reached before the opening position when inserting the microfluidic device (20) into the cavity (14) of the receiving device (10).

7. Microfluidic system according to claim 6, arranged such that the inner volume increases when the microfluidic device (20) is beyond the threshold position and that a gas located between the fluidic sample and the valve (31 ) is vented into the inner volume via the gas path (30) when the microfluidic device is at or beyond the opening position.

8. Microfluidic device according to claim 1 , wherein the chamber (12) comprises a mobile wall (13) limiting a side of the inner volume, arranged to be moved by the microfluidic device (20) when the microfluidic device (20) is beyond the threshold position.

9. Microfluidic device according to claim 8, wherein the mobile wall (13) is mechanically connected to the microfluidic device (20) when the microfluidic device (20) is at and beyond the threshold position.

10. Microfluidic system according to claim 2, wherein the microfluidic device (20) is arranged to contain a biological fluidic sample (25) which can flow through the fluidic circuit (28) when the microfluidic device (20) is at or beyond the opening position.

11. Microfluidic system according to claim 10, being a biosensor, wherein the receiving device (10) comprising detection means able to detect at least one analyte contained in the sample, after the sample is flowed through the fluidic circuit (28).

12. Fluid actuation device (10) comprising:

- an opened cavity (14) for receiving a microfluidic device (20) having a microfluidic circuit (28) able to contain a fluidic sample (25);

a chamber (12) comprising an inner volume and a wall having an opening (1 1 ) therethrough in communication with the inner volume and comprising a mobile wall (13) limiting partly the inner volume; a gas path (30) extending between the opening (11 ) and the cavity (14) to allow a gas but not the fluidic sample (25) flowing between the chamber (12) and the microfluidic device (20), via another opening (21 ) provided through an outer wall of the microfluidic device (20) and communicating with the fluidic circuit (25); - actuator (16) between the mobile wall (13) and a bottom portion of the cavity (14) such that the inner volume of the chamber (12) is modified when the position of the microfluidic device (20) into the cavity (14) is beyond a threshold position from which the microfluidic device (20) actuates the actuator (16).

13. Fluid actuation device according to claim 12, wherein the actuator (16) comprises a U-shaped shaft.

14. Fluid actuation device according to claim 13, wherein the chamber (12) and the cavity (14) are adjacent one to the other.

15. Fluid actuation device according to claim 12, wherein the actuator (16) further comprises an elastic member (19) provided between the mobile wall (13) and a fixed part of the device such that a restoring force is exerted onto the mobile wall (13) towards an equilibrium position when the elastic member (19) is strained.

16. Fluid actuation device according to claim 12, wherein the chamber (12) is cylindrical and the mobile wall (13) is a piston.

17. Fluid actuation device according to claim 12, comprising a stop member (13a) to stop the cartridge (20) into the cavity (14) at a stop position.