EP1843833B1 - Method and device for dosing and mixing small amounts of liquid, apparatus and use - Google Patents

Abstract

A method or device for integrated dosing and intermixing of small amounts of liquid, has a first liquid conveyed into or onto a first reservoir (3). A second reservoir (1) is entirely filled with a second liquid. The first and second liquids are brought into contact with each other via at least one joining duct structure (5) which has at least one area provided with a smaller cross section than the reservoirs (1,3) in the viewing direction of the connecting line between the two reservoirs (1,3). A laminar flow pattern is created along at least one portion of the joining duct structure (5), with the liquids thoroughly mixed in the second reservoir (1).

Description

The invention relates to a method for integrated metering and mixing of small amounts of liquid, a device and an apparatus for carrying out this method and a use.

Diagnostic assays, especially in the field of clinical chemistry and immunochemistry, are now largely automated. In the appropriate machines, defined volumes of sample liquid and reagents are pipetted into a cuvette or into the well of a microtiter plate and mixed. Subsequently, a first reference measurement is carried out in which, for example, the optical transmission through the cuvette is determined. After a certain reaction time between sample and reagents, a second measurement of the same parameter is made. By comparing the two measured values results in the concentration of the sample with respect to a particular ingredient or even the presence of the ingredient. Typical volumes are in the sum of a few hundred microliters, whereby necessary mixing ratios of sample to reagent between 1: 100 and 100: 1 can occur. Optionally, several reagents may be provided for mixing with a sample. In addition to the high throughput instruments just described, which are typically found in specialized laboratories, there are also efforts to make assays decentralized and without much instrumental effort. It would be desirable if the recently introduced "lab-on-a-chip" technology could be used, in which the Processing of liquids can be performed on or integrated into a chip. Assay times of less than one hour are desirable.

For example, microfluidic systems are used to move the liquids, in which liquid is moved by electro-osmotic potentials, see for example Anne Y. Fu, et al. "A micro fabricated fluorescence-activated cell sorter", Nature Biotechnology Vol. 17, November 1999, p. 1109 et seq ,

A method for mixing liquids in the microliter range is in DE 103 25 307 B3 described in which small volumes of liquid in microtiter plates are mixed by means of sound-induced flow. Another method of generating motion in small quantities of fluid on a solid surface describes DE 101 42 789 C1 , Here, a liquid is mixed with the help of surface sound waves or mixed several liquids together.

According to a in DE 100 55 318 A1 described method, an amount of liquid is brought to a region of a substantially planar surface, the wetting properties of which differ from the surrounding surface in such a way that the liquid preferably resides on it, being held together by their surface tension. Movement of the amount of liquid can be generated by the momentum transfer of a surface acoustic wave to the liquid.

In particular, the integration of metering and mixing of sample and reagents in a low-cost lab-on-the-chip system is problematic. A homogeneous mixing of different such small amounts of liquid is difficult to implement.

For dosing, it is necessary to precisely define volumes of liquid quantities. This is geometrically feasible, for example. For example, in an open system, the wetting properties of the surface can determine a volume, as in FIG DE 100 55 318 A1 is described. Here, the volumes are defined by hydrophilic and hydrophobic regions over the wetting angle on a substantially smooth surface. If several volumes have been defined in this way which are to be reacted, the volumes are moved toward one another in order to achieve this. When moving on a surface, liquid residues or liquid molecules of the analyte or the reagent can adhere to the surface, so that the movement of a volume loss or a concentration reduction of unknown level can not be excluded. In addition, provision must be made against the evaporation, which can be problematic especially at longer assay times.

Other approaches use channels of defined cross-section, which are filled with liquid capillary. If the liquid is an aqueous solution, then at the end of the channel a hydrophobic barrier is attached, which can not be filled capillary. Furthermore, there is a lateral branch on this channel with a likewise hydrophobic surface, which can not be capillary filled. The cross-section and length of the channel between the hydrophobic barrier and the hydrophobic branch now define a volume which can be separated and moved by pneumatic pressure through the branch ( Burns et al., An integrated nanoliter DNA analysis device, Science 282, 484 (1998 )). This type of volume definition creates high costs due to the necessary wetting structuring the surface (hydrophilic for filling the channel itself and hydrophobic for the barrier and the branch). In addition, you must work with air pressure, which requires appropriate devices. In order to enable the capillary filling of the measuring channel, the channel cross-section must be small. For large volumes in the range of a few 100 microliters, therefore, long channels are required. This inevitably leads to large unwanted interactions of the molecules in the liquid with the channel wall. An efficient mixing of several. Liquid quantities are almost impossible in this geometry.

US 5,674,742 describes a device for manipulating, reacting and detecting small amounts of liquid with a first reservoir for a first quantity of liquid, a reaction reservoir and a connection channel structure connecting the reservoir, which has a cross-section in a region in the direction of the connecting line of the reservoir, which is smaller than the cross-sections of the reservoirs is. The apparatus includes means for generating flow along the connection channel structure and mixing the amounts of liquid in the second reservoir.

The term "liquid" in the present text includes i.a. pure liquids, mixtures, dispersions and suspensions; and liquids containing solid particles, for example, biological material. For example, dosing and mixing liquids may also be two or more similar solutions that differ in ingredients dissolved therein that are to be reacted.

The object of the present invention is to provide a method and a device by means of which a precise metering of liquid quantities on or in an integrated chip is possible and which enable precise mixing of the liquids.

This object is achieved by a method having the features of claim 1, a device having the features of claim 18 and an apparatus having the features of claim 28. Subclaims are directed to preferred embodiments. An advantageous use is. Subject of claim 29.

In a method according to the invention for the integrated metering and mixing of small volumes of liquid, a first liquid is produced placed in or on a first reservoir. A second liquid is brought into or onto a second reservoir in such a way that it is completely filled. The first and second liquids are brought into contact via at least one first connection channel structure which comprises at least one region which has a smaller cross section than the reservoirs themselves in the direction of the connection line of the two reservoirs. Liquid exchange is effected by laminar flow in the connection channel structure and the liquids are mixed in and on the second reservoir.

In the method according to the invention, the liquids come into contact via the connecting channel structure. At the interface between the two liquids, only negligible diffusion occurs because the cross-section of the connection channel structure is comparatively small. If a laminar flow is generated along the connection channel structure in the direction of the second reservoir, the first liquid is moved through the connection channel structure in the direction of the second reservoir. For example, by accurately selecting the period of time over which the laminar flow is generated in the connection channel structure, or the flow rate, a precise definition of the volume of the first liquid to be metered to the second liquid is made. The amount of the second liquid is precisely determined by the size of the reservoir. In or on the second reservoir then optionally takes place the reaction between the liquids. The second reservoir thus constitutes a reaction chamber. The method according to the invention enables the metering and mixing of liquids in a large dynamic range. Thus, the mixing ratio of reagents to sample liquid z. B. from 1: 100 to 100: 1 can be set.

To fill the reservoirs at the beginning of the process according to the invention, pipettes and / or corresponding filling structures can be used. The precision requirements of these elements are low, since the definition of the volumes of liquid participating in the reaction are determined by the method according to the invention or the device itself, in particular by the duration or the velocity of the laminar flow in the connection channel structure and the Volume of the second reservoir.

The laminar flow is preferably caused by the irradiation of sound waves towards at least a part of the connection channel structure.

The reservoirs and the connection channel structure may be configured three-dimensionally or two-dimensionally. Thus, the reservoirs and interconnect channel structures may be correspondingly shaped depressions in a surface. Other configurations are correspondingly shaped cavities. In a two-dimensional embodiment, the reservoirs and connection channel structures are formed by correspondingly shaped regions of a surface, which are wetted by the liquids more preferably than the surrounding regions of the surface. Such wetting-modulated surfaces are, for example, in DE 100 55 318 A1 described. The liquids are held by their surface tension on the preferably wetted areas.

For ease of illustration, three-dimensional and two-dimensional implementations are included in the present text, unless explicitly stated otherwise, even if terms are chosen that seem to describe only one possibility. So for example for the Applying a liquid to a two-dimensional reservoir surface uses the term "introduction into a reservoir" or "filling". Similarly, z. For example, the term "movement through the connection structure" is used also for the movement of fluid on a two-dimensional connection structure. The "volume" or the size of a "cross-section" in two-dimensional implementations analogously means the area or the width.

The amount of the second liquid participating in the reaction is determined by the dimensions of the second reservoir. If the second reservoir, for example via corresponding filling structures, for. As filling channels and / or filling, filled, any existing supernatants of liquid in these filling structures outside of the reservoir for geometric reasons do not participate in the mixing, especially when the mixing is effected by laminar flow pattern.

In an advantageous embodiment of the method according to the invention, the laminar flow is generated in or on the connecting channel structure with the aid of sound waves. Preferably surface acoustic waves are used, which can be generated for example with one or more interdigital transducers. Surface sound waves transmit their impulse to the liquid or substances contained in it in order to put it in motion. In general, the momentum transfer from surface acoustic waves generated by interdigital transducers to liquids on surfaces in DE 100 55 318 A1 described.

In a development according to the invention using an interdigital transducer, the latter has a radiation direction in the direction of the extension of at least one part of the connection channel structure.

The first and second liquids may be contacted via the connection channel structure using, for example, capillary forces. For this purpose, the connecting channel structure is chosen so small in its lateral dimensions, that at least one of the liquids is pulled by the capillary forces along the channel. So z. For example, according to a preferred method, a first liquid can be brought onto or into the first reservoir, which propagates through the capillary forces in or on the connection channel structure. At the point of entry of the connecting channel structure into the second reservoir, the liquid stops its movement, since only small capillary forces act through the larger cross-section of the reservoir compared to the connecting channel structure. In or on the second reservoir, the second liquid is applied, which comes into contact with the first liquid at the entry point of the connecting channel structure in the second reservoir.

In another process, the connection between the two liquids is made via a small "bridge drop" which is placed between the two liquids and creates a liquid bridge. The bridge drop has a much smaller volume than either of the two liquid quantities.

To fill the reservoirs at the beginning of the process according to the invention, pipettes and / or corresponding filling structures can be used. The requirements for the precision of these elements are low, since the definition of the participating in the reaction volumes of liquid by the inventive method or the inventive Device itself, in particular by the duration or the speed of the laminar flow in the connection channel structure and the volume of the second reservoir.

The filling structures may also comprise filling channel structures with small cross-sections compared to the reservoirs. The production of a corresponding structure is very simple, since the same process steps are used, which are also used in the production of the reservoir or in the connecting channel structure.

The comparatively small cross-sections effectively prevent any supernatants present after filling in the filling channel structures from taking part in the mixing. In this way it is prevented that possibly existing liquid supernatants in the filling channel structures make the specification of the liquid volumes participating in the mixing inaccurate.

In addition, it is additionally ensured by small cross sections of the filling structures that uncontrolled diffusion due to liquid boundaries possibly present in the filling structures is negligible due to the small cross section.

Such filling channel structures can have a small cross-section, which ensures that the liquid moves through the filling channel structures or on the filling channel structures due to capillary action in the direction of the reservoirs. For a precise filling is easy to carry out.

The inventive method can be carried out with a single connection channel structure between the two reservoirs. This is the first reservoir at least partially emptied by the laminar outflow of the first liquid. Another embodiment according to the invention comprises at least two connecting channel structures between the two reservoirs. In one of these connecting channel structures, for example, a laminar flow is generated by means of surface acoustic waves, which serves for moving the first liquid from the first reservoir in the direction of the second reservoir. The first fluid in the first reservoir is thus becoming less and less due to the laminar outflow. At the same time, second liquid flows into the first reservoir from the second reservoir via the second connection channel structure.

After adding the desired amount of the first liquid to the second liquid in the second reservoir, the liquids are mixed. It is particularly favorable if this mixing process is effected by generating substantially laminar flow patterns. This ensures that any supernatants at the filling structures take part in the mixing as little as possible or not at all.

In particular sound waves, which are radiated into the second reservoir, are suitable for generating such flow patterns. You can z. B. be generated using surface acoustic waves. These can be used directly to generate flow in the liquid by their momentum transfer. In other implementations, the surface acoustic waves can be used to radiate sound waves through a solid, such as a reservoir bottom, into the liquid. For the generation of surface acoustic waves known per se interdigital transducers can be used, which can be easily produced by lithographic techniques.

It is preferred if separate devices are used to produce the laminar flow and the mixing. However, the invention also includes embodiments in which the laminar flow and the mixing are produced with the same device.

The method according to the invention is not limited to the metering and mixing of only two quantities of liquid. Thus, for example, additional reservoirs may be connected to the second reservoir in addition via further connecting channel structures, from which further fluids are metered into the second reservoir. The addition can be done simultaneously or sequentially.

A device according to the invention for metering small quantities of liquid has a first reservoir for a first liquid, a second reservoir for a quantity of a second liquid and at least one connecting channel structure which connects the two reservoirs and has at least in one region a cross section in the direction of the line of connection of the reservoirs which is smaller than the cross sections of the reservoirs. The reservoirs and the at least one connecting channel structure may be formed as depressions or cavities in a solid body. In a two-dimensional embodiment of the device according to the invention, the reservoirs and the at least one connecting channel structure are formed by surface areas which are more preferably wetted by the liquids.

The device according to the invention furthermore has at least one device for generating laminar flow along the at least one connecting channel structure. A preferred embodiment comprises a device for generating sound waves, preferably surface acoustic waves. The use is at least particularly simple an interdigital transducer for generating surface acoustic waves, which can be easily produced by lithographic techniques.

In addition, the device according to the invention has at least one device for mixing the quantities of liquid in or on the second reservoir. In a preferred embodiment, a second sound wave generating device is provided for generating sound waves entering the second reservoir.

The device according to the invention can be designed as a cost-effective and practical disposable part.

A device according to the invention, which is to be used for metering and mixing of more than two quantities of liquid, has a corresponding number of reservoirs with a corresponding number of connection channel structures for integrated metering and mixing of more than two quantities of liquid.

Advantages of the device according to the invention and preferred embodiments of the dependent claims will become apparent from the above description of the advantages and preferred embodiments of the method according to the invention.

The method according to the invention and the device according to the invention can be used particularly effectively for the metering and mixing of biological fluids, in which a precise metering of very small amounts of fluid is necessary.

The devices according to the invention can be operated automatically with a correspondingly designed automatic machine.

Fig. 1

einen waagerechten Querschnitt durch eine erfindungsgemäße Vorrichtung,

Fig. 2

einen Schnitt durch eine erfindungsgemäße Vorrichtung der Fig. 1 entlang der Linie A-B,

Fig. 3

einen Schnitt durch eine erfindungsgemäße Vorrichtung der Fig. 1 entlang der Linie C-D,

Fig. 4

den Schnitt der Fig. 2 bei Durchführung eines Schrittes des erfindungsgemäßen Verfahrens,

Fig. 5

eine Abwandlung der erfindungsgemäßen Vorrichtung der Fig. 1 im waagerechten Querschnitt,

Fig. 6

den Ausschnitt einer Oberfläche einer weiteren Ausführungsform der erfindungsgemäßen Vorrichtung mit benetzungsmodulierter Oberfläche,

Fig. 7

eine seitliche Teilansicht der Ausführungsform der Fig. 6 während der Durchführung des erfindungsgemäßen Verfahrens,

Fig. 8

eine Teilansicht auf eine Oberfläche einer Abwandlung der Ausführungsform der Fig. 6,

Fig. 9

eine seitliche Teilansicht dieser Ausführungsform während der Durchführung eines Schrittes des erfindungsgemäßen Verfahrens, und

Fig. 10a - 10c

waagerechte Querschnitte durch eine erfindungsgemäße Ausführungsform während dreier unterschiedlicher Verfahrenszustände.

Embodiments and embodiments of the invention will be explained in detail with reference to the attached figures. The figures are not necessarily to scale and are for schematic illustration. It shows:

Fig. 1

a horizontal cross section through a device according to the invention,

Fig. 2

a section through an inventive device of Fig. 1 along the line AB,

Fig. 3

a section through an inventive device of Fig. 1 along the line CD,

Fig. 4

the cut of the Fig. 2 when performing a step of the method according to the invention,

Fig. 5

a modification of the device according to the invention the Fig. 1 in horizontal cross section,

Fig. 6

the detail of a surface of a further embodiment of the device according to the invention with wetting-modulated surface,

Fig. 7

a partial side view of the embodiment of the Fig. 6 during the implementation of the method according to the invention,

Fig. 8

a partial view of a surface of a modification of the embodiment of the Fig. 6 .

Fig. 9

a partial side view of this embodiment during the implementation of a step of the method according to the invention, and

Fig. 10a - 10c

horizontal cross sections through an embodiment of the invention during three different process states.

The embodiment schematically illustrated in FIGS Fig. 1 to 4 includes a disposable part made of plastic, for example. While Fig. 1 shows the horizontal cross-section to illustrate the arrangement of the individual elements, shows Fig. 2 a section along the line AB and Fig. 3 a section along the line CD.

The individual elements are, as it is in the Fig. 2 to 4 clearly recognizable cavities in the plastic part. In the lateral sectional figures, only the cavities are shown. The structures can be formed for example by pressing metallic counterparts of the molds and subsequently with a film - here from below - be completed. Alternatively, the plastic part can be produced as an injection molded part.

The reservoir 1, for example, occupies a volume of 100 or 150 μl, while the reservoir 3 holds a volume of 5 μl. Reservoirs 1 and 3 are connected to each other via a capillary channel 5.

The reservoir 1 is connected via two further channels 7 with upwardly open filling nozzle 17. The channels 7 also have such a small cross-section that capillary forces act on a liquid therein. The reservoir 3 is connected via a capillary channel 11 with the filling nozzle 19.

The dimensions and the process control are chosen so that the Reynolds number of the considered liquids is in the range of the laminar flow. The necessary parameters can be determined in preliminary tests. Typical viscosities of liquids used are in the range of 1 mPa.s to several 100 mPa.s at speeds of 1 mm per second to 1 cm per second. Suitable system cross sections are then in the range of a few 100 microns with a total length of a few cm.

13 denotes an acoustic chip. This is, for example, a piezoelectric solid-state chip on which an interdigital transducer for generating surface acoustic waves is applied in a manner known per se.

In the embodiment shown, the interdigital transducer on the acoustic chip 13 is a unidirectional radiating transducer which generates surface acoustic waves only in the direction of the reservoir 1.

15 designates a further acoustic chip, which likewise carries an interdigital transducer in a manner known per se. This interdigital transducer is configured in such a way that the surface sound waves generated with it enable sound wave radiation into the reservoir 1. The emission of sound waves into a liquid volume, the is removed by a solid from the surface acoustic wave generating interdigital transducer is in DE 103 25 307 B3 described. The acoustic chip 15 may, for. B. also be provided on the other side of the reservoir 1.

The acoustic chips 13, 15 are connected via electrical connections, not shown, to an AC voltage source, with which an AC voltage of a frequency of a few tens of MHz can be generated in order to produce surface acoustic waves with the interdigital transducers.

Such a device is used as follows for carrying out the method according to the invention. About the filling nozzle 19 and the capillary channel 11, the reservoir 3 is filled with a small amount of liquid. Due to capillary forces, this liquid enters the channel 5. However, the liquid does not enter the reservoir 1, because there the cross-section is considerably larger and so the capillary force is abruptly weaker.

The reservoir 1 is pressurized, for. B. completely filled by a pipette with a larger amount of another liquid. It is harmless if 17 supernatants remain in liquid in the filling channels 7 for the reservoir 1 or the filling nozzle. These do not participate in the mixing process to be carried out later by generating laminar flow patterns in the reservoir 1 for geometrical reasons and are therefore not relevant for the determination of the liquid volume participating in the mixing process.

There is automatically a contact between the first liquid, which is in the channel 5 and the second liquid, which fills the reservoir 1. Due to the small cross-section of the channel 5, only a negligible diffusion between the two liquids occurs at this fluidic connection.

By means of the unidirectional transducer on the chip 13, whose emission direction is directed towards the reservoir 1, a laminar flow is generated by the momentum transfer of the surface acoustic waves to the liquid in the channel 5. By selecting the time duration over which the interdigital transducer is operated, or the pumping power, the amount of liquid which flows laminarly via the capillary channel 5 into the reservoir 1 can be precisely determined. The determination of the necessary time duration or the pumping power can be determined for example on the basis of preliminary tests. The laminar flow thus ensures a defined supply of liquid.

The liquid, which in this way penetrates from the channel 5 into the reservoir 1, is replaced by liquid, which is withdrawn from the reservoir 3.

Applying an alternating electric field to the interdigital transducer of the acoustic chip 15 below the reservoir 1 leads to a mixing of the liquids with the aid of a laminar flow pattern, as shown in FIG Fig. 4 is indicated. The thus generated irradiation of sound waves in the liquid on the reservoir 1 provides a substantially laminar flow pattern, which leads to the mixing of the liquids. The substantially laminar flow pattern thereby guarantees that any supernatants of liquid in the filling structures do not participate in the mixing due to geometric reasons.

The reservoir 1 then serves as a reaction chamber in which a reaction of the two defined amounts of liquid or their ingredients can take place.

Fig. 5 shows a modification of the embodiment of the Fig. 1 to 4 , Here, the capillary channel 6 between the reservoir 3 and the reservoir 1 is not rectilinear. An acoustic chip 14 with an interdigital transducer is used, which does not have to radiate unidirectionally here. It is sufficient if the acoustic chip 14 is arranged such that one of its emission directions points in the direction of the capillary channel 6. By operation of the acoustic chip 14, a surface acoustic wave is radiated in the indicated direction, the momentum transfer of which leads to the liquid in the capillary channel 6 to a laminar flow.

The 6 and 7 show an embodiment that can be realized on the surface of a solid state chip. Here, the reservoirs 101 and 103 include surface regions whose wetting properties are selected such that they are preferably wetted by a liquid. In the case of aqueous liquids, the reservoirs 101, 103 are hydrophilic compared to the surrounding solid surface. This is z. B. achieved by silanization of the surrounding surface, which leads to a hydrophobic surface.

In the embodiment of the 6 and 7 For example, the reservoirs 101 and 103 are connected by a laminar connection channel structure 105 whose wetting properties are also selected. On the surface is located in a manner not shown, an interdigital transducer whose emission direction along the channel 105 goes to produce laminar flow in the channel 105. The channel 105 is selected so narrow that capillary forces act on liquid thereon.

Such a device is used as follows. A liquid drop 123 of a first liquid is applied to the reservoir 103 and, due to the described wetting properties of the surface, does not move outward from the reservoir 103 and is held together by its surface tension. Due to capillary forces, this liquid moves along the channel structure 105. The abruptly decreasing capillary forces at the junction between the channel structure 105 and the larger reservoir surface 101 stops the movement of the liquid at the juncture between the channel structure 105 and the reservoir surface 101. A second liquid drop 121 is applied to the reservoir surface 101. Also, this liquid drop 121 is held together by the selected wetting properties of the surface and its surface tension. Its size is selected so that the reservoir surface 101 is completely filled. By selecting the size of the surface 101 so that the volume is determined. At the junction between the channel structure 105 and the reservoir surface 101, only negligible diffusion of the two liquids occurs due to the small cross section of the channel structure 105. By operation of the interdigital transducer, not shown, the emission direction of which runs along the channel structure 105, a laminar flow is generated along the channel structure 105, which, just as in the three-dimensional embodiments of FIGS Fig. 1 to 5 for liquid transport along the channel structure 105 leads.

In the area of the reservoir surface 101 is an interdigital transducer, with the aid of which a laminar flow pattern for mixing the liquids is produced. The interdigital transducer is in the 6 and 7 also not shown for the sake of clarity.

The functioning of the two - dimensional structure of 6 and 7 corresponds to the operation of the three-dimensional structures of the Fig. 1 to 5 ,

In the side view of the Fig. 7 For example, the liquid drop 121 on the reservoir surface 101, the liquid drop 123 on the reservoir surface 103, and the liquid bridge 125 along the channel structure 105 can be seen.

8 and 9 show a modification of the embodiment of the 6 and 7 , The reservoir surfaces 101 and 103 are not interconnected by a channel structure 105 here. A connection of the amounts of liquid 121 and 123 is done here by deliberately introducing a "bridge drop" 127 small volume, which provides a liquid bridge between the two liquid quantities, via which by means of the as in the embodiment of 6 and 7 generated laminar flow in the manner described a liquid transport can take place.

Fig. 10 serves the schematic representation of another procedure. Reservoirs 201 and 203 are interconnected via two capillary structures 223, 227. An interdigital transducer 213, which is indicated only schematically, has at least one emission direction along the channel structure 227. Beneath the reservoir 201 is a surface acoustic wave generation device 215, eg, a surface acoustic wave generator 215. B. also an interdigital transducer, which can emit a sound wave in the liquid in the overlying reservoir similar to the surface acoustic wave generating device 15 already described.

In the reservoir 203, a first liquid is introduced. The liquid enters the capillaries 223, 227 due to the capillary force. A second liquid is introduced into the reservoir 201 for its complete filling. The operation of the interdigital transducer 213 generates a surface acoustic wave at least in the direction indicated. By the momentum transfer of the surface acoustic wave to the liquid in the channel 227, a laminar flow is generated there.

The liquid from the channel 227 enters the reservoir 201 and is replenished from the reservoir 203. In this case, the liquid boundaries 229, 231 move accordingly. Since it is a laminar and not a turbulent flow, apart from the diffusion at the liquid boundaries 229, 231 no mixing takes place. It creates a state like him in Fig. 10b is shown.

By selecting the time duration and the pumping power during which the interdigital transducer 213 is used to generate the surface acoustic wave, the respective proportion of the liquids in the reservoir 201 can be determined. By operation of the interdigital transducer 215, a surface acoustic wave is generated, which leads to the radiation of a sound wave in the liquid in the reservoir 201 and there causes corresponding flow pattern for mixing the two liquids. It creates a mixture 233, as in Fig. 10c indicated.

Also, the embodiment of Fig. 10 with multiple connection channel structures between the reservoirs can be carried out both two-dimensionally with corresponding wetting structures as well as three-dimensionally with corresponding recesses or cavities.

In all the described embodiments, total volumes of up to 1 ml for single volumes of e.g. B. only 100 nl be treated. The figures are not to scale. This is the ratio of the volumes the channel structures to the volume of the reservoirs z. Between 1/10 and 1/100.

If a corresponding number of reservoirs and connecting channel structures are provided, several liquids can be added simultaneously or successively and mixed.

The method according to the invention and the devices according to the invention make it possible to precisely meter in a quantity of liquid to a quantity of liquid defined by the volume of the second reservoir, for example by selecting the time during which a laminar flow is generated along the connection channel structure of the devices according to the invention. The method is easy to carry out and the device can be made small, compact and possibly disposable.

The embodiments according to the invention can be operated in an automaton. Such a machine has z. Example, a receptacle for a device according to the invention, which makes electrical contact with the interdigital transducers. Automatically operated pipetting heads and / or dispensers are provided, which are arranged in such a way that they are arranged above the reservoirs or the filling structures when the device is inserted in the receptacle. Finally, a control, preferably provided with a microprocessor unit, which serves for timing the pipetting heads / dispensers and the interdigital transducer in order to process a desired metering and mixing protocol. In the machine and the evaluation instruments, such. B. optical measuring devices, etc., to detect the possibly triggered by the mixing process reaction.

LIST OF REFERENCE NUMBERS

1

Reservoir, reaction chamber

3

reservoir

5, 6

Verbindungskapillarstruktur

7, 11

Befüllkanäle

13, 14, 15

acoustic chip

17, 19

filling union

101

Reservoir surface, reaction chamber

103

reservoir area

105

planar connection channel structure

121, 123

liquid drops

125

liquid bridge

127

bridge drops

201

Reservoir, reaction chamber

203

reservoir

213, 215

interdigital transducer

223, 227

Connecting channel structures

229, 231

liquid boundaries

233

liquid mixture

Claims (29)

1. A method for the integrated metering and mixing of small quantities of liquid, wherein
   a first liquid is introduced into or onto a first reservoir (3, 103, 203);
   a second reservoir (1, 101, 201) is completely filled with a second liquid;
   the first and the second liquids are brought into contact via at least one connection passage structure (5, 6, 105, 227) which comprises at least one region which has a smaller cross-section than the reservoirs in the direction of view of the connection line of the two reservoirs;
   laminar flow is generated in the connection passage structure (5, 6, 105, 227) for the liquid exchange of the two liquids; and
   the liquids are mixed in or on the second reservoir (1, 101, 201).
2. A method in accordance with claim 1, wherein the liquid exchange is effected by radiation of sound waves in the direction of at least one part of the connection passage structure (5, 6, 105, 227).
3. A method in accordance with claim 2, wherein the radiation of sound waves for the generation of the liquid exchange in the laminar flow region is maintained over a defined time period.
4. A method in accordance with one of the claims 2 or 3, wherein the laminar flow is generated with the help of the pulse transfer of surface sound waves.
5. A method in accordance with claim 4, wherein the surface sound waves are generated using at least one interdigital transducer (213) with a radiation device in the direction along at least one part of a connection passage structure (5, 6, 105, 227).
6. A method in accordance with any one of the claims 1 to 5, wherein at least one of the liquids is introduced into or onto the at least one connection passage structure (5, 6, 105, 227) while utilizing capillary forces.
7. A method in accordance with claim 6, wherein initially a first liquid (123) is introduced into or onto the first reservoir (3, 103, 203) which spreads out through capillary forces through the connection passage structure (5, 105, 227) up to the second reservoir (1, 101, 201) and then a second liquid (121) is introduced into or onto the second reservoir (1, 101, 201) which comes into contact with the first liquid at the inlet position of the connection passage structure (5, 6, 105, 201) into the second reservoir (1, 101, 201).
8. A method in accordance with any one of the claims 1 to 5, wherein the contact of the two quantities of liquid (121, 123) is established via a third quantity of liquid (125) having a volume smaller than both that of the first quantity of liquid and that of the second quantity of liquid which is introduced between the first quantity of liquid and the second quantity of liquid.
9. A method in accordance with any one of the claims 1 to 8, wherein sound waves are used for the mixing of the liquids in or on the second reservoir (1, 101, 201).
10. A method in accordance with claim 9, wherein surface sound waves are used for the generation of the sound waves for the mixing.
11. A method in accordance with claim 10, wherein at least one interdigital transducer (215) is used for the generation of the surface sound waves.
12. A method in accordance with any one of the claims 1 to 11, wherein the filling of the reservoir (1, 101, 201, 3, 103, 203) takes place via filling passage structures (7, 11).
13. A method in accordance with any one of the claims 1 to 12, wherein the two reservoirs (201, 203) are in communication via at least two connection passage structures (223, 227).
14. A method in accordance with any one of the claims 1 to 13, wherein correspondingly shaped wells are used in a surface as the reservoirs and/or at least one passage structure.
15. A method in accordance with any one of the claims 1 to 13, wherein correspondingly shaped hollow spaces are used as the reservoirs (1, 3) and as at least one passage structure (5, 6, 7, 11).
16. A method in accordance with any one of the claims 1 to 13, wherein correspondingly shaped regions of a surface are used as reservoirs (101, 103) and as at least one passage structure (105) and are more preferably wetted by the liquids (121, 123, 125) than the surrounding regions of the surface.
17. A method in accordance with any one of the claims 1 to 16, wherein more than two liquids are metered and mixed with the help of a corresponding number of reservoirs and connection passage structures.
18. A device for the integrated metering and mixing of small quantities of liquids comprising
    a first reservoir (3, 103, 203) for a first quantity of liquid (123);
    a second reservoir (1, 101, 201) for a second quantity of liquid (121);
    at least one connection passage structure (5, 6, 105, 227) which connects the two reservoirs and has a cross-section in at least one region in the direction of view of the connection line of the reservoirs which is smaller than the cross-sections of the reservoirs;
    at least one device for the generation of a laminar flow along the at least one connection passage structure (5, 6, 105, 227); and
    at least one device (15, 215) for the mixing of the quantities of liquid in or on the second reservoir (1, 101, 201),
    characterized in that
    the device comprises filling passage structures (7, 11) which are in communication with a reservoir at one respective end and with a filling device (17, 19) at the other respective end;
19. A device in accordance with claim 18, wherein the at least one device for the generation of laminar flow includes at least one first sound wave generation device (13, 213) having at least one radiation device along at least one part of the at least one connection passage structure (5, 6, 105, 227).
20. A device in accordance with claim 19, having at least one surface threshold generation device (13, 213), in particular an interdigital transducer (213), having a radiation direction in the direction of at least one region of the connection passage structure (5, 227) for the generation of the laminar flow in or on the connection passage structure.
21. A device in accordance with any one of the claims 18 to 20, wherein the device for the mixing includes at least one second sound wave generation device (15, 215) for the generation of sound waves entering into the second reservoir (1, 101, 201).
22. A device in accordance with claim 21, having at least one surface sound wave generation device (15, 215), in particular an interdigital transducer (215), in the region of the second reservoir (1, 101, 201) for the generation of sound waves entering into the second reservoir (1, 101, 201).
23. A device in accordance with any one of the claims 18 to 22, wherein the at least one connection passage structure (5, 6, 105, 227) has such a narrow cross-section that capillary forces are exerted onto at least one of the liquids by the side boundaries.
24. A device in accordance with any one of the claims 18 to 23, wherein the reservoirs and the at least one passage structure are formed by wells in a surface.
25. A device in accordance with any one of the claims 18 to 23, wherein the reservoirs (1, 3) and the at least one passage structure (5, 6, 7, 11) are formed by hollow spaces.
26. A device in accordance with any one of the claims 18 to 23, wherein the reservoirs (101, 103) and the at least one passage structure (105) are defined by regions on a surface which are more preferably wetted by the liquids (121, 123, 125) than the surrounding surface.
27. A device in accordance with any one of the claims 18 to 26, having more than two reservoirs and a corresponding number of connection passage structures for the integrated metering and mixing of more than two quantities of liquid.
28. An apparatus for the automatic carrying out of a method in accordance with any one of the claims 1 to 17, having
    a receiver for a device in accordance with any one of the claims 18 to 27,
    electrical contacts which, when the device is placed in the receiver, electrically contact the at least one device (5, 14, 213) for the generation of laminar flow along the at least one connection passage structure and the at least one device (15, 215) for the mixing of the quantities of liquid in or on the second reservoir;
    devices for the automatic supply of liquid to the reservoirs (1, 3, 101, 103, 201, 203) of the device placed in the receiver; and
    a control, preferably including a microprocessor, for the control of the at least one device (5, 14, 213) for the generation of laminar flow, of the at least one device (5, 215) for the mixing and of the devices for the automatic supply of liquid.
29. Use of a method in accordance with any one of the claims 1 to 17, of a device in accordance with any one of the claims 18 to 27 or of an apparatus in accordance with claim 28 for the metering and mixing of biological liquids.

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