MICROFLUIDIC ANALYSIS DEVICE

Description

Field of the Invention

[0001] The present invention relates to microanalysis devices and methods for moving fluids in such devices.

Prior Art

[0002] The idea is applicable to (but not limited to) micro-analysis systems that are based on microchannels formed in a rotatable, usually plastic, disc, often called a "centrifugal rotor" or "lab on a chip". Such discs can be used to perform analysis and separation on small quantities of fluids. In order to reduce costs it is desirable that the discs should be not restricted to use with just one type of reagent or fluid but should be able to work with a variety of fluids. Furthermore it is often desirable during the preparation of samples that the disc permits the user to dispense accurate volumes of any desired combination of fluids or samples without modifying the disc. Due to the small widths of the microchannels, any air bubbles present between two samples of fluids in the microchannels can act as separation barriers or can block the microchannel and thereby can prevent a fluid from entering a microchannel that it is supposed to enter. In order to overcome this problem US patent no. 5 591 643 teaches the use of a centrifugal rotor which has microchannels that have cross sectional areas which are sufficiently large that unwanted air can be vented out of the microchannel at the same time as the fluid enters the microchannel.

Object of the invention.

[0003] An object of the present invention is to provide a structure for a centrifugal rotor and a method for using such a centrifugal rotor, which structure and which method permits the reliable transport of fluids in the centrifugal rotor.

[0004] A further object of the present invention is to provide a structure for a centrifugal rotor and a method for using such a centrifugal rotor, which structure and which method permits the accurate metering of fluids in the centrifugal rotor.

Summary of the Invention

[0005] The present invention achieves the objects of the invention by means of a structure having the features of claim 1. A method for using such a structure to achieve the objects of the invention has the features of claim 5.

Brief Description of the Figures

[0006] The present invention will be illustrated by a non-limiting example of an embodiment by means of the following figures, where:

Figure 1a shows the peripheral part of a centrifugal rotor having five radially extending microchannel structures K7-K12 in accordance with the present invention;

Figure 1b shows an enlarged view of one microchannel structure from figure 1a in accordance with the present invention;

Figure 1c shows an enlarged view of a sample volume-defining structure in the microchannel structure of figure 1b;

Figure 1d shows an enlarged view of the chamber area plus chambers for the disposal of waste fluids, wherein variations in depth are shown by cross-hatching;

Figures 2a and 2b show the structure of figure 1b with the chamber containing a first fluid;

Figures 3a and 3b shows the addition of a second fluid to a volume-defining chamber;

Figures 4a and 4b show the replacement of the first fluid in the chamber by said second fluid;

Figure 5 shows a second embodiment of a microchannel structure in accordance with the present invention;

Figure 6 shows a third embodiment of a microchannel structure in accordance with the present invention; and

Figure 7 shows a fourth embodiment of a microchannel structure in accordance with the present invention.

Figure 8 shows a fifth embodiment of a microchannel structure in accordance with the present invention.

Detailed Description of Embodiments Illustrating the Invention

[0007] The microchannel structures (K7-K12) in accordance with the present invention are shown in figures 1a-d arranged radially on a microfluidic disc (D).
Suitably the microfluidic disc is of a one- or two-piece moulded construction and is formed of an optionally transparent plastic or polymeric material by means of separate mouldings which are assembled together (e.g. by heating) to provide a closed structure with openings at defined positions to allow loading of the device with fluids and removal of fluid samples. Suitable plastic of polymeric materials may be selected to have hydrophobic properties. Preferred plastics or polymeric materials are selected from polystyrene and polycarbonate. In the alternative, the surface of the microchannels may be additionally selectively modified by chemical or physical means to alter the surface properties so as to produce localised regions of hydrophobicity or hydrophilicity within the microchannels to confer a desired property. Preferred plastics are selected from polymers with a charged surface, suitably chemically or ion-plasma treated polystyrene, polycarbonate or other rigid transparent polymers.

[0008] The microchannels may be formed by micro-machining methods in which the micro-channels are micro-machined into the surface of the disc, and a cover plate, for example, a plastic film is adhered to the surface so as to enclose the channels. The microfluidic disc (D) has a thickness which is much less than its diameter and is intended to be rotated around a central hole so that centrifugal force causes fluid arranged in the microchannels in the disc to flow towards the outer periphery of the disc. In the embodiment of the present invention shown in figures 1a-1d, the microchannels start from a common, annular inner application channel (1) and end in common, annular outer waste channel (2), substantially concentric with channel (1). It is also possible to have individual application channels (waste channels for each microchannel or a group of microchannels. Each inlet opening (3) of the microchannel structures (K7-K12) may be used as an application area for reagents and samples. Each microchannel structure (K7-K12) is provided with a waste chamber (4) that opens into the outer waste channel (2). Each microchannel (K7-K12) forms a U-shaped volume-defining structure (7) and a U-shaped chamber (10) between its inlet opening (3) and the waste chamber (4). The normal desired flow direction is from the inlet opening (3) to the waste chamber (4) via the U-shaped volume-defining structure (7) and the U-shaped chamber (10). Flow can be driven by capillary action, pressure and centrifugal force, i.e. by spinning the disc. As explained later, hydrophobic breaks can also be used to control the flow. Radially extending waste channels (5), which directly connect the annular inner channel (1) with the annular outer waste channel (2), in order to remove an excess fluid added to the inner channel (1), are also shown.

[0009] Thus, fluid can flow from the inlet opening (3) via an entrance port (6) into a volume-defining structure (7) and from there into a first arm of a U-shaped chamber (10). The volume-defining structure (7) is connected to a waste outlet for removing excess fluid, for example, radially extending waste channel (8) which waste channel (8) is preferably connected to the annular outer waste channel (2). The waste channel (8) preferably has a vent (9) that opens into open air via the top surface of the disk. Vent (9) is situated at the part of the waste channel (8) that is closest to the centre of the disc and prevents fluid in the waste channel (8) from being sucked back into the volume-defining structure (7).

[0010] The chamber (10) has a first, inlet arm (10a) connected at its lower end to a base (10c) which is also connected to the lower end of a second, outlet arm (10b). The chamber (10) may have sections I, II, III, IV which have different depths, for example each section could be shallower than the preceding section in the direction towards the outlet end, or alternatively sections I and III could be shallower than sections II and IV, or vice versa. A restricted waste outlet (11), i.e. a narrow waste channel, is provided between the chamber (10) and the waste chamber (4). This makes the resistance to fluid flow through the chamber (10) greater than the resistance to fluid flow through the path that goes through volume-defining structure (7) and waste channel (8).

[0011] Due to the relatively large width of the waste chamber (4), the top and bottom surfaces of the waste chamber (4) are preferably separated by one or more supports (12) to ensure that the top and bottom surfaces of the microfluidic device do not bend inwards towards the waste chamber (4) and thereby change its volume.

[0012] As shown in figures 1a-c, the volume-defining structure (7) is U-shaped with the entrance port (6) opening into the upper end (i.e. the end nearest to the centre of the disc) of one of the arms (7a) of the U and the waste channel (8) connected to the upper end of the other arm (7b) of the U. The vent (9) is also placed at the top of this other arm (7b). The base (7c) of the U-formed volume-defining structure (7) is connected to the upper end of a first arm (10a) of the chamber (10).

[0013] In addition to the application area at the inlet (3) of the structure, there may also be an additional application area (13) that opens out into the top surface of the disc and is connected to the entrance port (6). This additional application area (13) can be used when it is desired to add different reagents or samples to each of the different microstructures (K7-K12).

[0014] There is preferably also a vent (14) to open air in the chamber (10). A hydrophobic break is preferably provided at the connection (16) of the chamber (10) to the volume-defining structure (7) in order to guide fluid into arm (7b)

[0015] The outer annular waste channel (2) may be sectioned so as to collect waste from a selected number of closely located microchannel structures.

[0016] Hydrophobic breaks can be introduced into the microchannel structures (K7-K12), for example by marking with an over-head pen (permanent ink) (Snowman pen, Japan), and suitable places for such breaks (shown by crosshatching in the figures) include: (a) between microchannel structure inlets (3) in the inner annular application channel (1), (b) each opening (15) into the outer annular waste channel (i.e. the openings of the waste chambers) and, (c) if present, also the radial waste channels (5) which connect the inner annular application channel (1) and the outer annular waste channel (2), and also the waste channel (8) which guides away excess fluid from the volume-defining structure (7).

[0017] The purpose of the hydrophobic breaks is to prevent capillary action from drawing the fluid into undesired directions. Hydrophobic breaks can be overcome by centrifugal force i.e. by spinning the disc at high speed.

[0018] If the sample to be analysed is in the form or cells or sedimenting material or particles then it can be held in the lower U-channel by a particle filter (21) (shown by a dotted line in figure 1b and 1d) or the flow through the chamber (10) can be controlled such that particles are retained in the chamber while fluids flow through it - as will be described later.

[0019] A first reagent or sample fluid X can be introduced into the chamber (10) by connecting a source (not shown) of the fluid X to the common annular inner application channel (1) from where it flows by capillary action and/or, if the disc is spun, centrifugal force to the lower U-bend. If the volume of fluid X which is introduced into common annular inner application channel (1) is in excess (i.e. is greater than the volume of the chamber (10) up to the level of the restricted channel (11) (distance L4 in figure 1d)) then some of it flows to waste via the radial waste channels (5 and 8) while the rest flows to waste chamber (4) via the chamber (10) though the restricted channel (11) as shown in figure 2. This continues until the levels of fluid X in both the left hand and right hand arms of the chamber (10) are the same as the distance L4, i.e. the U-shaped chamber is full up to the level of the restricted channel (11). This is shown in figure 2b) where the excess fluid X has flowed out of the microchannel structure via the waste chamber (4) and radial waste channels (5 and 8) to the outer waste channel (2) or via the restricted channel (11).

[0020] When it is time to add a new reagent or sample fluid Y, then fluid Y is added by the common annular inner application channel (1) (or, alternatively, as shown in figure 3a) by the additional application area (13)). The fluid Y travels by capillary action through the volume-defining structure (7) and down the waste channels (5 and 8) as shown in figure 3a). It cannot flow into chamber (10) as the air cushion (19) contained between the base of the volume defining structure and the top of the fluid in arm (7a) of the chamber acts as a barrier to prevent the fluid flowing into chamber (10). Note that optionally an air cushion (19) can be left between the first fluid X and the second fluid Y by making the distance L4 from the base of the U-bend in the chamber (10) to the restricted channel (11) less than the distance L3 from the base of the U-bend in the chamber (10) to the base of the U-bend of the volume-defining structure (7). This can prevent the second fluid Y from flowing by capillary action into the chamber (10) and can also prevent mixing of the fluids X and Y. The vent (9), which is open to atmospheric pressure, makes it easier for the second fluid Y to flow towards the waste channel (2). Gentle, i.e. low speed, spinning of the disc (D) empties the excess fluid Y from waste channel (8), leaving the volume-defining structure (7) full of fluid Y, as shown in figure 3b.

[0021] All of the first fluid X in the chamber (10) can be displaced by the second fluid Y by spinning the disc if the volume of the second fluid in the volume-defining structure (7) and any air between the first and second fluids is equal to or greater than the volume of the first fluid X in the chamber (10). This can be achieved by ensuring that the volume of the volume-defining structure (7) is greater than the volume of the chamber (10). This can be achieved by making the arms (7a) and (7b) of the volume-defining structure longer than the arms of the chamber (10), and/or by making the cross-sectional area of the arms of the volume-defining structure (7) greater than that of the arms of the chamber (10). Figure 4a shows an intermediate situation where the disc is being spun and centrifugal force causes fluid Y to flow from the volume-defining structure (7) into chamber (10), thereby displacing first fluid X which flows to waste via restricted channel (11). Any excess second fluid Y flows out of the chamber (10) through the restricted channel (11) into waste chamber (4). Figure 4b shows that the second fluid Y has replaced the first fluid X. This process can be repeated using different fluids as often as is desired.

[0022] In the event that the fluids contain particles and it is desired to hold them in the chamber it is possible to provide the chamber (10) with a particle filter (21) with suitable sized orifices. In the event that it is necessary to only temporarily hold the particles in the chamber (10) then the sections I, II, III, IV of the chamber (10) which have different depths can be used to temporarily trap the particles. This is done by increasing the speed of rotation of the disc so that the particles collect at the boundary wall between two sections while the fluid flows over the wall.

[0023] In another aspect of the invention, particles can be selectively held in, or flushed out of a chamber (10'), which does not have a particle trap or sections having different depths as shown in figure 5. This can be achieved as follows:

[0024] Particles that have been sedimented, or otherwise collected, in the bottom of the chamber (10') can be drawn out of the chamber (10') by the meniscus of a fluid which flows out of the chamber (10'). In other words, if there is an air cushion (19') between the volume-defining structure and the chamber (10') and this is driven through the chamber, then as the meniscus between the fluid in the chamber and the air cushion passes the particles they are entrained by the meniscus and flow out of the chamber. This can be achieved by choosing a suitably low rate of acceleration of the disc (known as "ramp speed"). If however it is desired to retain the particles in the chamber then it is necessary to ensure that the air cushion is not driven through the chamber (10') by the fluid in the volume-defining structure when the disc is spun. If a suitably high rate of acceleration of the disc is chosen, it is possible to cause the fluid in the volume-defining structure to flow down the sides of the channel, through the air cushion (19'), without displacing the air cushion (19'). Typically a ramp speed of up to 3500 rpm/s² transports the particles further in the channel system. With a ramp speed greater than 3500 rpm/s² the fluid/air interface (meniscus) does not enter the U-chamber and the air bubble stays still or moves in the opposite direction to the centrifugal force. The exact ramping speeds to achieve the desired effect are naturally dependent on the type of fluid used and are most suitably determined by experimentation.

[0025] In another embodiment of the invention, as shown in figure 6, the arm (7b') of the volume-defining structure (7') is not connected to a waste channel (8), but is instead enlarged at its end nearest the centre of the disk in order to form a reservoir (61) for fluid to prevent fluid overflowing out of a vent (9'). This vent and/or sample inlet (9') vents this reservoir (61) to atmosphere and can also permit samples to be introduced into the structure. The reservoir (61) preferably has a length which makes the length of the volume defining structure i.e. reservoir (61) and arm (7b') equal to or greater than the length of arm (7a'). If the vent (9') is made so small that the surface tension of the fluid prevents it from flowing out of the vent when the volume-defining structure (7') is being charged by spinning, then the amount of fluid which can enter the volume-defining structure (7') is minimised and no fluid is wasted. Naturally if it is desired to replace all the fluid in the chamber (10) with fluid from the volume defining structure then the volume of the volume defining structure must be greater than the volume of the chamber (10). If the arm (10a) of the chamber is made to widen from its upper end to its lower end then it is possible to push the air barrier (19) out of the chamber when adding a second fluid without the two fluids mixing.

[0026] All the chambers of the present invention can be provided with heating means in the form of a coating as shown crosshatched in figure 7. This coating (71), which can be painted or printed or applied in some other way to one or both sides of the disk in the vicinity of the chamber, can absorb energy from electromagnetic radiation which is directed onto it and thereby heat up the chamber. The incident radiation can be infra red light, laser light, visible light, ultraviolet light, microwaves or any other suitable type of radiation. The heating up of the chamber can be used to initiate or accelerate reactions in the chamber. If the disk is stationary while the chamber is being heated then if the fluid boils it will produce bubbles of vapour which will travel up the arms of the chamber and may even pass out into the waste channel (8) and waste chamber (4). This is not always desirable as it is often preferred that substantially all the fluid should remain in the chamber after the heating has been finished. This can be achieved in the present invention by spinning the disk at the same time that radiation is incident on the coating (71). The radiation sources (not shown) can be focused onto areas that the coating passes through as the disc spins. Furthermore the coating can be dimensioned such that heat is only applied to only the smallest amount of the base consistent with adequate heating of the reagents. In this way the arms of the U are keep cool and provide condensation surfaces for the fluid vapour to condense on. The centrifugal force exerted on the condensed vapour causes it to flow back into the base of the chamber.

[0027] Note that while the embodiments of the invention described above have a chamber leading to a waste chamber, it is of course conceivable that the chamber outlet leads to one or more further chamber(s). Each further chamber may have a plurality of inlets and a plurality of outlets so that samples and reagents may be combined in a chamber. The subsequent results of any process, which has taken place in a chamber, can be dispensed to one or more additional chambers for further processing or sent to the waste channel. An example of this is shown in figure 8. Figure 8 shows a microstructure, of a design similar to that shown in figure 6, in which the base (110c) of U-shaped chamber (110) is connected by a base outlet channel (134) to a second chamber (136), which second chamber (136) is positioned further away from the centre of the disk than second chamber (110). Second chamber (136) is vented to atmosphere by a vent (138) that opens out on the top surface of the disc. Second chamber (136) is also provided with an inlet/outlet connection (140) that also opens out on the top surface of the disk. Inlet/outlet (140) can be used to supply substances to second chamber (136) e.g. by injecting them into connection (140) and/or to extract substances from second chamber (136) e.g. by sucking them out via connection (140). Fluid is prevented from flowing by capillary action from chamber (110) into base outlet channel (134) by a hydrophobic break (132) positioned at or near the junction (130) between the base (110c) of chamber (110) and base outlet channel (134). Hydrophobic break (132) is dimensioned so that when the disc is spun at a certain number of revolutions per second then any fluid in chamber (110) leaves the chamber via chamber outlet arm (110b), and when the disc is spun at a higher number of revolutions per minutes then the centrifugal force acting on the fluid is sufficient to overcome the hydrophobic effect of hydrophobic break (132) and the fluid flows into second chamber (136). In this embodiment of the present invention, the outlet arm (110b) of chamber (110) is almost as long as inlet arm (1 10a). Thus when chamber (110) is filled with a fluid the level of fluid in inlet arm (110b) will be very close to the base (107c') of the volume-defining structure (107'). This means that when a second fluid is supplied to the volume-defining structure (107'), e.g. via inlet (109') in the reservoir (161), it will come into direct contact with the first fluid in the chamber (110) and no air bubble will form between the two fluids. This arrangement can be used to facilitate mixing of two fluids.

[0028] The above mentioned examples of conceivable embodiments are intended to illustrate the present invention and are not intended to limit the scope of protection claimed by the following claims.

Claims

1. Microstructure for fluids provided in a rotatable disc (D) characterised in that it comprises a U-shaped volume-defining structure (7, 107) comprising:

• a first arm (7a) connected at or near its upper end to an entrance port (6) wherein the lower end of said first arm (7a) is further from, or the same distance from, the centre of said disc (D) than/as, said entrance port (6);

• a second arm (7b) connected at or near its upper end to a first waste channel (8) or sample inlet or vent (9',109') via a reservoir (61,161) for fluid, wherein said waste channel (8), if present, is further away from the centre of said disc (D) than said entrance port (6); and

• a base (7c) positioned further from said centre of said disc (D) than said first and second arms (7a, 7b) and which base (7c) connects the lower ends of said first and second arms (7a, 7b), wherein said base (7c) is connected to an inlet arm (10a, 110a) of a U-shaped chamber (10, 110), at or near to the upper end of said inlet arm (10a), wherein said U-shaped chamber (10, 110) further comprises;

• a base (10c, 110c) and an outlet arm (10b, 110b), wherein said base (10c, 110c) connects the lower end of said inlet arm (10a, 110a) to the lower end of said outlet arm (10b, 110b), and said outlet arm (10b, 110b) is connected at or near its upper end to a second waste outlet (11) and said base (10c, 110c) is further from, or the same distance from, the centre of said disc (D) than/as the lower ends of said inlet and outlet arms (10a, 10b; 110a, 110b) of said U-shaped chamber (10, 110).

2. Microstructure in accordance with claim 1 characterised in that said first waste channel (8) is provided with a vent (9).

3. Microstructure in accordance with claim 1 characterized in that the second arm (7b) is connected to the vent or the sample inlet (9',109').

4. Microstructure in accordance with any of claims 1-3 characterised in that the resistance to fluid flow through said second waste outlet (11) is greater than the resistance to fluid flow through said first waste channel (8).

5. Microstructure in accordance with any of the previous claims characterised in that the length of the first U-shaped volume-defining structure (7, 107) is greater than the length of the second U-shaped chamber structure (10, 110).

6. Microstructure in accordance with any of the previous claims characterised in that said chamber structure (10, 110) is at least partly covered by a coating (71), which can absorb energy from electromagnetic radiation which is directed onto it and thereby heat up said chamber structure (10).

7. Microstructure in accordance with any of the previous claims characterised in that in said chamber structure (10, 110) has sections I, II, III, IV which have different depths and which can be used to trap and release sedimenting material or other particles.

8. Microstructure in accordance with any of the previous claims characterised in that in said chamber structure (110) is connected by its base (110c) to a second chamber (136) positioned further from said centre of said disc (D) than said chamber structure (110) by means of a channel (134), wherein there is a hydrophobic break (132) positioned at or near the junction (130) between the chamber (110) and the channel (132).

9. The use of a microstructure in a rotatable disc (D) in accordance with any of the previous claims to dispense predetermined volumes of fluid to a chamber (10, 110) in said rotatable disk.

10. Method for replacing an original fluid in a chamber (10, 110) in a rotatable disk (D) characterised by the steps of:

• providing a microstructure in accordance with any of claims 1-8 containing said original fluid in chamber (10,110);

• filling said volume-defining structure (7) with a replacement fluid; and

• rotating said disk (D) at a sufficiently high speed such that said replacement fluid moves under centrifugal force into said chamber while at the same time the original fluid in the chamber (10) is forced out of the chamber by the incoming replacement fluid.

Ansprüche

1. Mikrostruktur für Fluide, die in einer drehbaren Scheibe (D) vorgesehen ist, dadurch gekennzeichnet, dass sie eine U-förmige, ein Volumen definierende Struktur (7, 107) aufweist, mit:

- einem ersten Arm (7a), der an seinem oberen Ende oder in der Nähe seines oberen Endes mit einem Einlassanschluss (6) verbunden ist, wobei das untere Ende des ersten Arms (7a) vom Zentrum der Scheibe (D) weiter als oder ebenso weit wie der Einlassanschluss (6) entfernt ist;

- einem zweiten Arm (7b), der an seinem oberen Ende oder in der Nähe seines oberen Endes über einen Fluidvorratsbehälter (61, 161) mit einem ersten Abfallkanal (8) oder Probeneinlass oder Entlüftungsloch (9', 109') verbunden ist, wobei der Abfallkanal (8), falls vorhanden, weiter vom Zentrum der Scheibe (D) als der Einlassanschluss (6) entfernt ist; und

- einer Basis (7c), die vom Zentrum der Scheibe (D) weiter als der erste und der zweite Arm (7a, 7b) positioniert ist, wobei die Basis (7c) die unteren Enden des ersten und des zweiten Arms (7a, 7b) verbindet und mit einem Einlassarm (10a, 110a) einer U-förmigen Kammer (10, 110) an dem oberen Ende oder in der Nähe des oberen Endes des Einlassarms (10a) verbunden ist, wobei die U-förmige Kammer (10, 110) ferner umfasst:

- eine Basis (10c, 110c) und einen Auslassarm (10b, 110b), wobei die Basis (10c, 110c) das untere Ende des Einlassarms (10a, 110a) mit dem unteren Ende des Auslassarms (10b, 110b) verbindet, der Auslassarm (10b, 110b) an seinem oberen Ende oder in der Nähe seines oberen Endes mit einem zweiten Abfallauslass (11) verbunden ist und die Basis (10c, 110c) vom Zentrum der Scheibe (D) weiter als die unteren Enden des Einlass- und des Auslassarms (10a, 10b; 110a, 110b) der U-förmigen Kammer (10, 110) oder ebenso weit wie diese entfernt ist.

2. Mikrostruktur nach Anspruch 1, dadurch gekennzeichnet, dass der erste Abfallkanal (8) mit einem Entlüftungsloch (9) versehen ist.

3. Mikrostruktur nach Anspruch 1, dadurch gekennzeichnet, dass der zweite Arm (7b) mit dem Entlüftungsloch oder mit dem Probeneinlass (9', 109') verbunden ist.

4. Mikrostruktur nach einem der Ansprüche 1-3, dadurch gekennzeichnet, dass der Fluidströmungswiderstand durch den zweiten Abfallauslass (11) größer als der Fluidströmungswiderstand durch den ersten Abfallkanal (8) ist.

5. Mikrostruktur nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Länge der ersten U-förmigen, ein Volumen definierenden Struktur (7, 107) größer als die Länge der zweiten U-förmigen Kammerstruktur (10, 110) ist.

6. Mikrostruktur nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Kammerstruktur (10, 110) wenigstens teilweise durch eine Beschichtung (71) abgedeckt ist, die Energie von elektromagnetischer Strahlung, die auf sie gerichtet ist, absorbieren kann, wodurch die Kammerstruktur (10) aufgeheizt wird.

7. Mikrostruktur nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass in der Kammerstruktur (10, 110) Abschnitte I, II, III, IV vorhanden sind, die unterschiedliche Tiefen besitzen und verwendet werden können, um Sedimentmaterial oder andere Partikel einzufangen und freizugeben.

8. Mikrostruktur nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Kammerstruktur (110) durch ihre Basis (110c) mit einer zweiten Kammer (136), die weiter vom Zentrum der Scheibe (D) als die Kammerstruktur (110) positioniert ist, mittels einer Kammer (134), in der ein wasserabweisender Abschnitt (132) vorhanden ist, der bei dem Übergang oder in der Nähe des Übergangs (130) zwischen der Kammer (110) und dem Kanal (132) positioniert ist, verbunden ist.

9. Verwendung einer Mikrostruktur in einer rotierenden Scheibe (D) nach einem der vorhergehenden Ansprüche, um vorgegebene Fluidvolumina an eine Kammer (10, 110) in der drehbaren Scheibe abzugeben.

10. Verfahren zum Austauschen eines Originalfluids in einer Kammer (10, 110) in einer drehbaren Scheibe (D), gekennzeichnet durch die folgenden Schritte:

- Vorsehen einer Mikrostruktur nach einem der Ansprüche 1-8, die das Originalfluid in der Kammer (10, 110) enthält;

- Befüllen der ein Volumen definierenden Struktur (7) mit einem Austauschfluid; und

- Drehen der Scheibe (D) mit einer ausreichend hohen Geschwindigkeit, so dass sich das Austauschfluid unter der Zentrifugalkraft in die Kammer bewegt, während gleichzeitig das Originalfluid in der Kammer (10) durch das eintretende Austauschfluid aus der Kammer gezwungen wird.

Revendications

1. Microstructure pour fluides disposée dans un disque rotatif (D), caractérisée en ce qu'elle comprend une structure définissant un volume en forme de U (7, 107), comprenant :

. un premier bras (7a) relié à son extrémité supérieure ou au voisinage de celle-ci à un orifice d'entrée (6), dans lequel l'extrémité inférieure dudit premier bras (7a) est plus éloignée, ou à la même distance, du centre dudit disque (D) que ledit orifice d'entrée (6) ;

. un deuxième bras (7b) relié à son extrémité supérieure ou au voisinage de celle-ci à un premier canal d'évacuation (8) ou évacuation ou orifice d'entrée d'échantillon (9', 109'), par l'intermédiaire d'un réservoir (61, 161) pour fluide, dans lequel ledit canal d'évacuation (8), s'il est présent, est plus éloigné du centre dudit disque (D) que ledit orifice d'entrée (6) ; et

. une base (7c) positionnée plus loin dudit centre dudit disque (D) que lesdits premier et deuxième bras (7a, 7b), cette base (7c) reliant les extrémités inférieures desdits premier et deuxième bras (7a, 7b), ladite base (7c) étant reliée à un bras d'entrée (10a, 110a) d'une chambre en forme de U (10, 110), à l'extrémité supérieure dudit bras d'entrée (10a) ou au voisinage de celle-ci, ladite chambre en forme de U (10, 110) comprenant de plus :

. une base (10c, 110c) et un bras de sortie (10b, 110b), ladite base (10c, 110c) reliant l'extrémité inférieure dudit bras d'entrée (10a, 110a) à l'extrémité inférieure dudit bras de sortie (10b, 110b), et ledit bras de sortie (10b, 110b) étant relié, à son extrémité supérieure ou au voisinage de celle-ci, à un deuxième orifice de sortie d'évacuation (11), et ladite base (10c, 110c) étant plus éloignée, ou à la même distance, du centre dudit disque (D) que les extrémités inférieures desdits bras d'entrée et de sortie (10a, 10b ; 110a, 110b) de ladite chambre en forme de U (10, 110).

2. Microstructure selon la revendication 1, caractérisée en ce que ledit premier canal d'évacuation (8) est muni d'une évacuation (9).

3. Microstructure selon la revendication 1, caractérisée en ce que le deuxième bras (7b) est relié à l'évacuation ou à l'orifice d'entrée d'échantillon (9', 109').

4. Microstructure selon l'une quelconque des revendications 1 à 3, caractérisée en ce que la résistance à l'écoulement de fluide à travers ledit deuxième orifice de sortie d'évacuation (11) est supérieure à la résistance à l'écoulement de fluide à travers ledit premier canal d'évacuation (8).

5. Microstructure selon l'une quelconque des revendications précédentes, caractérisée en ce que la longueur de la première structure définissant un volume en forme de U (7, 107) est supérieure à la longueur de la deuxième structure de la chambre en forme de U (10, 110).

6. Microstructure selon l'une quelconque des revendications précédentes, caractérisée en ce que ladite structure de chambre (10, 110) est au moins partiellement recouverte par un revêtement (71), qui peut absorber l'énergie d'un rayonnement électromagnétique qui est dirigé sur celui-ci, et, par conséquent, chauffer ladite structure de chambre (10).

7. Microstructure selon l'une quelconque des revendications précédentes, caractérisée en ce que ladite structure de chambre (10, 110) comporte des sections I, II, III, IV qui ont des profondeurs différentes et qui peuvent être utilisées pour piéger et libérer des matériaux de sédimentation ou d'autres particules .

8. Microstructure selon l'une quelconque des revendications précédentes, caractérisée en ce que ladite structure de chambre (110) est reliée par sa base (110c) à une deuxième chambre (136) positionnée plus loin dudit centre dudit disque (D) que ladite structure de chambre (110) à l'aide d'un canal (134), dans lequel se trouve une interruption hydrophobe (132) positionnée à la jonction (130) entre la chambre (110) et le canal (132) ou au voisinage de celle-ci.

9. Utilisation d'une microstructure dans un disque rotatif (D) selon l'une quelconque des revendications précédentes, pour distribuer des volumes prédéterminés de fluide à une chambre (10, 110) dans ledit disque rotatif.

10. Procédé pour remplacer un fluide original dans une chambre (10, 110) dans un disque rotatif (D), caractérisé par les étapes consistant à :

. disposer une microstructure selon l'une quelconque des revendications 1 à 8, contenant ledit fluide original dans une chambre (10, 110) ;

. remplir ladite structure définissant un volume (7) par un fluide de remplacement ; et

. faire tourner ledit disque (D) à une vitesse suffisamment élevée pour que ledit fluide de remplacement se déplace sous l'effet de la force centrifuge vers l'intérieur de ladite chambre, tandis qu'en même temps, le fluide original dans la chambre (10) est forcé hors de la chambre par le fluide de remplacement entrant.

Drawing