DE102010028012A1 - Liquid control for micro flow system - Google Patents

Abstract

The invention relates to a method and a device for the controlled transport of a liquid within a flow system, in particular a micro flow system. According to the invention, the transport of an aqueous liquid in a flow system is controlled primarily with the aid of pentadecane, that is to say C15H32. For this purpose, a flow system is provided which includes pentadecane for controlling liquid transport within the flow system. The flow system is completely or partially flooded with pentadecane for control purposes.

Description

The invention relates to a method and a device for a controlled transport of a liquid within a flow-through system, in particular a micro-flow system.

A micro flow system is a device with channels whose diameter is less than 1 mm. In particular, the channel diameters are a maximum of 150 μm. Such a micro flow system is typically manufactured using semiconductor techniques. It is therefore also known to choose semiconductors as material to fabricate channels. But other materials such as polymers or glass can be used. A micro flow system according to the present invention then includes channels and components that are integrated into a substrate. From the publication US Pat. No. 7,144,616 B1 such a micro flow system emerges.

In the pharmaceutical industry, several hundred thousand different substances are tested daily for their suitability as starting materials for new drugs. Such requirements have the consequence that there is a need for micro flow systems that can handle minute amounts of liquid precisely. Micro flow systems are also used in industrial process engineering to quickly and evenly mix the smallest quantities of liquid. In the biochemical field microsystems are used for the analysis of biological samples.

Micro flow systems are very small and are being built increasingly smaller. The components used must be correspondingly small. There is therefore a constant need for further miniaturization of the components used.

So-called lab-on-a-chip systems, known for example from the publications " Robin Hui Liu, Jianing Yang, Ralf Lenigk, Justin Bonanno, and Piotr Grodzinski: Self-Contained, Fully Integrated Biochip for Sample Preparation, Polymerase Chain Reaction Amplification, and DNA Microarray Detection, Anal. Chem. 2004, 76, 1824-1831 " such as " R. Pal et al .: An integrated microfluidic device for influenza and other genetic analyzes, Lab Chip, 2005, 5, 1024-1032 ", Include micro flow systems. These are miniaturized diagnostic and / or analytical devices. Such systems are also referred to as "LoC" systems.

In flow systems, valves are needed to control material flows and / or open or close reaction chambers. For this purpose, usually mechanical valves (rotary valves, etc.) are used, which must be moved mechanically to change the opening state. In many cases there is a need in flow-through systems for adding a first liquid to a second liquid in a metered manner. According to the state of the art, a corresponding system of lines and valves is required to make such a dosage.

A mechanical valve for opening and closing a channel is from the document JP 2006183818 A or from the publication US Pat. No. 6,981,518 B2 known. According to the document US 6,981,151 B2 a mechanical valve element is linearly moved by means of a lever to open or close a channel. Various valves for micro flow systems are described in the publication " Chunsun Zhang et al., Micropumps. Microvalves, and micromixers within PCR microfluidic chips: Advances and trends, Biotechnology Advances 25 (2007) 483-514, Elsevier "Described. An overview of previously known valves for microfluidic flow systems can be found in addition in J. Micromech. Microeng. 16 (2006) R13-R39, A review of microvalves, Kwang W Oh et al. ,

In microfluidic, automated systems, the valves used must be dimensioned sufficiently small, which places high demands on the manufacturing accuracy of the valves. Furthermore, the valve control by servomotors or the like in the operator device of such a LoC system is to ensure.

Especially for use in the microfluidic field, alternative valve concepts that ensure the opening or closing of channels without mechanical activation are therefore found in the prior art. These concepts are wax, paraffin, hardening or icing valves. Their advantages are their small size (they are virtually part of the channel to be controlled) and the fact that for their control usually no additional mechanics is needed. As a rule, phase transitions from solid (including waxy) to liquid and vice versa are exploited. Such valves are from the documents " Yan He et al .: Capillary-based fully integrated and automated system for nanoliter polymerase chain reaction analysis directly from surface cells, Journal of Chromatography A, 924 (2001) 271-284 "," P. Selvaganapathy *, ET Carlen, CH Mastrangelo: Electrothermally Actuated Inline Microfluidic Valve, Sensors and Actuators A 104 (2003) 275-282 "," Lena Klintberg et al .: Fabrication of a paraffin actuator using hot embossing of polycarbonates, Sensors and Actuators A 103 (2003) 307-316 "," Robin Hui Liu, Jianing Yang, Ralf Lenigk, Justin Bonanno, and Piotr Grodzinski: Self-Contained, Fully Integrated Biochip for Sample Preparation, Polymerase Chain Reaction Amplification, and DNA Microarray Detection, Anal. Chem. 2004, 76, 1824-1831 "," R. Pal et al .: An integrated microfluidic device for influenza and other genetic analyzes, Lab Chip, 2005, 5, 1024-1032 "," Zongyuan Chen, Jing Wang, Shizhi Qian and Haim H. Construction: Thermally-actuated, phase change flow control for microfluidic systems, Lab Chip, 2005, 5, 1277-1285 " US 2008/0056949 A1 . US 2008/0112855 A1 . US 2007/0227592 A1 . US 2007/0231216 A1 . US 2004/0007275 A1 . US 2008/0314465 A1 . US 2005/0247356 A1 such as US 2005/0247357 A1 out. It is known to place a wax within a flow-through system and to liquefy it at the desired time.

Depending on the buffer used, icing disadvantageously requires relatively low temperatures of up to -20 ° C before an icing valve freezes and thus closes. Depending on the design, wax valves can only be switched once or twice and, depending on the design, require active activation via pump mechanisms for moving the wax. Known ice and wax valves do not solve the problem of the formation of air pockets during initial filling of microfluidic channel / cavity systems. To use wax valves, in addition to the manufacturing process of the fluidic cartridge, wax must still be positioned in the respective areas, which means an increased manufacturing cost.

It is the object of the invention to further develop the control of a microfluidic channel.

The object of the invention is achieved by a method in which the transport of a first, in particular aqueous, liquid in a flow-through system with the aid of a second adjacent liquid, in particular pentadecane, ie C ₁₅ H ₃₂ , is controlled by completely or partially flooding the flow-through system. The object of the invention is also achieved by a flow-through system which comprises the second liquid, in particular pentadecane, for controlling a liquid transport within the flow-through system. The second liquid is selected so that it can not be dissolved in the first liquid to be controlled and not mixed with the first liquid. Thus, the second liquid is a hydrophobic liquid when the first liquid is an aqueous liquid. In addition, the temperature of the first liquid that causes the first liquid to stop flowing is below the temperature of the second liquid that causes the second liquid to stop flowing. In the case of oils, such a temperature is known as "pour point".

According to the method, within the flow-through system, the first and second liquid are located in at least one channel and / or at least one chamber. The first and second liquids immediately adjoin one another. Both fluids move together within the flow system so as to obtain a transport or movement of the first fluid within the flow system. The movement of the first liquid is stopped by cooling at least a portion of the second liquid until it reaches the temperature that causes the second liquid to cease to flow. Preferably, however, it is not cooled so as to reach the temperature that causes the first liquid also to stop flowing. This ensures that the first liquid always remains flowable. It can then be particularly quickly and easily stopped the transport of the first liquid and started or continued.

Pentadecane is a water-insoluble, strongly hydrophobic, strongly wetting substance with a pour point of 5 ° to 10 ° and which thus stops above melting temperatures of aqueous solutions to flow. Due to these properties, pentadecane can be used to transport an aqueous liquid through desired regions of the flow-through system, in particular comprising one or more channels and / or one or more chambers, by pushing or pulling the aqueous liquid in front of it. Due to the highly hydrophobic properties of the pentadecane no or at least virtually no mixing with the aqueous liquid takes place. Pentadecane can first be pumped into the desired area of the flow system. Due to the strongly wetting properties of the pentadecane, this basically succeeds without bubbles. If, subsequently, the aqueous liquid is pumped into the desired area, the aqueous liquid completely displaces pentadecane and is thus free of bubbles in the intended area of the flow-through system. Subsequently, Pentadecan can be pumped into the intended area again to now push the liquid completely out of this area. The steps can therefore be carried out reversibly.

In the case of an aqueous liquid, C ₁₆ H ₃₄ , ie hexadecane or C ₁₄ H ₃₀ , ie tetradecane, are also particularly suitable. Hexadecane and tetradecane are basically flowable at a room temperature of 20 ° C. Both liquids behave hydrophobically and solidify at a temperature above 0 ° C. Both liquids therefore have similar advantages as pentadecane.

All three liquids have the advantage over paraffin, ie a mixture of alkanes, not of a mixture of several To pass substances. The pour point is correspondingly more predictable, which makes a more precise, easier control possible. In one embodiment, therefore, the second liquid is not present as a mixture.

Bubble-free filling, which is basically made very reliable by the invention, is particularly advantageous if such gas inclusions in liquid-filled reaction chambers expand by heating (eg denaturation step in a PCR) and can generate enormous pressure in the closed system. Another advantage of bubble-free filling is to maximize the available reaction volume so as to maximize effectiveness.

If a flow is to be stopped through an area, this is easily and quickly achieved by a corresponding decrease in the temperature of the second liquid for the purpose of solidification. The solidifying second liquid may then be in front of or behind the first, in particular aqueous, liquid whose further transport is to be stopped. For example, if pentadecane exists within the flow-through system in solidified form, thus blocking the flow through an area of the flow-through system, sufficient elevation of the temperature of the pentadecane is sufficient to (re) enable the corresponding flow.

In one embodiment, therefore, a chamber of the micro throughflow system is filled with pentadecane and then the aqueous liquid is pumped via a feeding channel into the pentadecane filled chamber. In this way, a chamber of a flow-through system, in particular a micro-flow system can be filled bubble-free even with the aqueous liquid, if there are means such as a stirring in the chamber, which complicate a bubble-free filling.

Such a flow-through system can be used, for example, to carry out a PCR. The aqueous liquid is then water with the ingredients required to perform a PCR.

Since a second liquid such as pentadecane solidifies at 5 to 10 ° C, the transport of an aqueous liquid by solidifying or liquefying pentadecane in a conventional environment in which room temperature prevails can be controlled with little energy input.

A transport by solidification can be controlled virtually automatically by a section of the throughflow system in the case of pentadecane being cooled to a pentadecane solidification temperature, an aqueous liquid being transported through this region by means of pentadecane, and the transport of the aqueous Liquid is stopped by passing pentadecane into the cooled area and solidifying. For this purpose, the aqueous liquid is preferably pressed into the cooled area with the aid of pentadecane. The area is then not cooled in such a way that the aqueous liquid solidifies. Such advantages and process steps can also be achieved with those second liquids which are comparable to pentadecane, such as tetradecane or hexadecane.

The cooled area comprises, for example, a chamber with a feed channel. First, the aqueous liquid enters the cooled channel and then into the cooled chamber. As seen in the flow direction behind the liquid is pentadecane and thus finally also enters the cooled channel. In the cooled channel the pentadecane solidifies, ie the C ₁₅ H ₃₂ . As a result, the further transport of the aqueous liquid stops. Preferably, the cooling temperature is 0 ° C to 5 ° C, on the one hand to cause a rapid solidification of the pentadecane and on the other hand to reliably prevent solidification of the aqueous liquid. In order to bring about a rapid solidification, the diameter of the channel in which pentadecane should solidify is preferably no more than 1 mm, particularly preferably not more than 600 μm, more preferably not more than 100 μm. The channel consists for example of polycarbonate, polypropylene or glass.

Generally, an aqueous liquid is transported within the flow-through system by pumping pentadecane into an area of the flow-through system in which the aqueous liquid is located. Pentadecan then slides the watery. Liquid in front of him, without mixing with this.

For carrying out the method, a flow-through system, in particular a micro-flow system, is provided which comprises pentadecane for controlling the transport of a liquid within the flow-through system. The pentadecane is then located in a chamber and / or in a channel of the flow-through system, specifically in a region which can be cooled to a temperature such that the pentadecane is able to solidify, but preferably not an aqueous solution. As a rule, cooling is therefore carried out to a positive temperature which is close to 0 ° C.

The flow-through system therefore comprises in particular means for cooling and / or heating the pentadecane therein. A Peltier element is suitable in the case of a chip-like structure of the flow system in a special way as a means for cooling and / or heating. However, other means of cooling and / or heating may be used, such as a flow-through system through which a cooled or heated liquid is passed.

Alternatively or additionally, the flow-through system can include heating and cooling means for carrying out a PCR in order to be able to carry out a PCR.

Alternatively or additionally, the flow-through system may comprise one or more reagents for carrying out an analysis or a PCR. Reagents may be housed in chambers of the flow-through system and be in liquid or dry form.

Aqueous first liquids used may be a reaction mixture for performing a nucleic acid amplification with or without prior reverse transcription.

With the aid of the invention, a PCR or an isothermal amplification (for example RPA, HDA, EXPAR) can be carried out, as is known from the documents " Myriam Vincent, Van Xu & Huimin Kong, Helicase-dependent isothermal DNA amplification, EMBO reports VOL 5, NO 8, 2004, p. 795 "," Olaf Piepenburg, Colin H. Williams, Derek L. Stemple, Niall A. Armes, DNA Detection Using Recombination Protein, PLoS Biology, July 2006, Volume 4, Issue 7, e204 "," J Effrey Van Ness, Lori K. Van Ness, and David J. Galas, Isothermal Responses to the Amplification of Oligonucleotides, 4504-4509, PNAS, April 15, 2003, Vol. 8th " are known.

• – Puffersubstanzen zur pH-Wert-Stabilisierung,
• – Salze zur Einstellung eines für die verwendeten Enzyme günstigen Milieus,
• – Enzyme wie DNA-Polymerase, Reverse Transkriptase, Restriktionsenzyme, Helicase, Recombinase etc.,
• – Koenzyme/Kofaktoren wie ATP, NADH,
• – Ausgangsstoffe der enzymatischen Reaktion (passende Oligonukleotide, Nukleotidtriphosphate),
• – die Reaktion unterstützende Stoffe wie DMSO, Betain, PEG etc.,

The required aqueous mixtures, ie first liquids in the sense of the invention, can essentially contain:

• Buffer substances for pH stabilization,
• Salts for the adjustment of a favorable environment for the enzymes used,
• Enzymes such as DNA polymerase, reverse transcriptase, restriction enzymes, helicase, recombinase, etc.,
• Coenzymes / cofactors such as ATP, NADH,
• - starting materials of the enzymatic reaction (suitable oligonucleotides, nucleotide triphosphates),
• Reaction-supporting substances such as DMSO, betaine, PEG etc.,

• – Puffersubstanzen und Salze wie oben beschrieben,
• – Analyten (Proteine, Nukleinsäuren),
• – Sonden (TaqMan-Sonden, Hybridisierungssonden (beides Oligonukleotide), markierte und unmarkierte Antikörper),
• – weitere eine Detektion der Analyten ermöglichende Stoffe wie Antikörper, Enzyme (Alkalische Phosphatase, Meerrettich-Peroxidase etc.), fluoreszente Proteine wie bspw. Phycoerythrin).

Aqueous mixtures which allow a detection reaction of an analyte and which may be a first liquid in the sense of the invention may contain:

• Buffer substances and salts as described above,
• - analytes (proteins, nucleic acids),
• Probes (TaqMan probes, hybridization probes (both oligonucleotides), labeled and unlabelled antibodies),
• Further substances enabling a detection of the analytes, such as antibodies, enzymes (alkaline phosphatase, horseradish peroxidase, etc.), fluorescent proteins, such as, for example, phycoerythrin).

Other aqueous or short-chain alcohols (methanol, ethanol, propanol) based mixtures of substances which are to be reacted with each other, as well as necessary auxiliaries may be first liquids according to the invention, which are used in particular in the field of microreaction technology.

In principle, all the above-mentioned mixtures as well as individual components of these mixtures in liquid or dry form may already have been accommodated in one or more chambers of the flow-through system by the manufacturer.

The invention will be explained in more detail below with reference to exemplary embodiments.

1 shows an unfilled polycarbonate micro reaction chamber 1 a micro flow system. The flow-through system was formed by a chip made of a polycarbonate which was suitably sealed with a polycarbonate film. The channel diameters were 600 μm. The chamber had an extension of 7.5 mm by 21 mm. Above the feeding channel at the top of the page 2 The chamber was filled with colored pentadecane and flooded, which, despite the stirring element 4 in the chamber 1 absolutely bubble-free succeeded, like the 2 clarified. Well, again over the feeding channel 2 , (differently colored) water into the pentadecane filled chamber 1 pumped. Pentadecan then flowed through the drainage channel 3 out of the chamber 1 out. This process led to a complete exchange of pentadecane by the water, like the 3 shows. The reaction chamber 1 So it was filled bubble-free with an aqueous liquid.

If the aqueous liquid is a mixture for carrying out a PCR, it can be mixed with the aqueous liquid according to 3 filled chamber to the known, PCR-typical temperature profiles are subjected to amplify nucleic acids.

Finally, the water was re-trapped with pentadecane from the microreaction chamber 1 pushed out what a further transport of the Reaction mixture from the chamber into another cavity corresponds. This exchange was again according to 4 completely and free of bubbles.

The described embodiment proves that pentadecane, which is reproducibly capable of filling microfluidic reaction chambers completely and without bubbles, can be completely displaced from the chamber with an aqueous buffer. This process is reversible because the embodiment also shows the subsequent displacement of the introduced aqueous buffer from the reaction chamber 1 with the help of pentadecane.

In a second embodiment it has been demonstrated that the flow of an aqueous medium in an in 5 shown, Pentadecan flooded channel system with open connections 5 to 10 is precisely steered by previous cooling of defined channel sections. That in the 5 The channel flow system shown again consisted of a base of milled polycarbonate sealed with a film of polypropylene. The channel diameter was again at 600 microns. The channel system was 70 mm wide (by 6 to 9 ) and 50 mm high (from 5 to 7 ). The filled channels are in the 5 illustrated with black lines. Subsequently, the direction of flow of colored water was controlled by ice / H2O-filled channeled tubes. The tubes 12 . 13 . 14 . 15 were like in the 6 shown above the channels attached directly to the terminals 6 . 7 . 9 and 10 to lead. The channels were thus cooled to near 0 ° C. The water was then in the connection 5 pumped in and joined the connection 8th out of the micro-flow system shown again.

This was the colored water - as in the 6 - directed in two for the fluid flow very unfavorable 90 ° angles. This proves that the freezing of pentadecane results in a robust closure of arbitrarily selectable channels.

The third embodiment described below demonstrates "automatic metering" of liquid volumes during filling operations and proves that this is feasible even with the simplest of tools.

A micro flow system was stored on ice to keep in the 7 shown feeding channel 2 to make "impassable" for Pentadecane. A two-phase liquid was then manually added to the downstream microreaction chamber via this feeding channel using a micropipette 1 filled. The two phases were purple colored water (lower phase) and blue colored PD (upper phase). Both liquids were aspirated into the pipette tip and without settling or interrupting in the channel 2 pumped. The filling of the reaction chamber stopped as soon as the pentadecane entered the ice-cooled channel 2 Although the filling pressure was maintained or increased with the aid of the micropipette, blue PD could not reach the reaction chamber. Pentadecan only reached as far as the 7 shown cooling point 11 ,

To check the existing overpressure, the opening of the pipette tip was removed from the channel entrance at the end of the pumping process, which led to the sudden leakage of the residual fluid.

After completion of the experiment, the reaction chamber was filled with water (exemplified by any reaction solution). The filling stopped automatically at the moment when the water was completely pumped into the chamber, thereby filling the channel in front with pentadecane. At that moment, the filling process ended without any further intervention (eg, driving a mechanical valve or stopping the pump).

In addition to the possibility of directing the flow direction of a fluid, it is thus possible with the Pentadecan used to stop the transport of an aqueous solution between different cavities of a closed system, for example, water, for example, for the return of dried reagents, automatically, as soon as the aqueous Liquid front has completely passed a desired cooled area or a desired cooled point of a flow system. The pentadecane following the water changes its state of aggregation from liquid to solid as soon as it reaches the cooled area or the cooled area and effectively prevents the further flow of the aqueous phase. This feature makes it possible to accurately measure liquid volumes without expensive measuring procedures and thus to fill cavities very accurately and reproducibly with a working liquid.

• • Die Schließtemperatur (Schmelztemperatur der Kanalfüllung) des Fluid gefüllten Kanals ist unabhängig vom verwendeten wässrigen Analysepuffer, was damit ausgestattete Mikrodurchflusssysteme beherrschbarer und leichter validierbar macht.
• • Die Schließtemperatur liegt erheblich höher als jene von Eisventilen (in jedem Fall über 0°C), was ein schnelleres Schließen des Kanals erlaubt.
• • Die Wärmekapazität des Phasenübergangs ist mindestens 30% geringer als beim Wasser-Eis-Übergang, was ebenfalls dazu führt, dass der Phasenwechsel schneller erfolgen kann als mit Wasser.
• • Das erfindungsgemäße Ventil ist beliebig oft schaltbar, da der zu schaltende Kanal immer wieder mit einer zweiten Flüssigeit befüllbar ist.
• • Der technische Aufwand zum Öffnen und Schließen eines Ventils ist erheblich geringer als konventionelle Ventiltechnik mit Ventilkörpern und Stellmotoren. Er ist auch geringer als der Aufwand zur Ansteuerung von zum Beispiel zweimal schaltbaren Wachsventilen nach Stand der Technik.
• • Der Herstellungsaufwand ist erheblich geringer, da im Produktionsprozess ein Einbringen von Wachs in den Ventilbereich, wie es bei herkömmlichen Wachsventilen zwingend notwendig ist, entfällt.
• • Das mikrofluidische Durchflusssystem wird insbesondere vor dem Befüllen mit einer ersten Flüssigkeit mit der zweiten Flüssigkeit befüllt. Handelt es sich bei der zweiten Flüssigkeit um eine stark benetzende Flüssigkeit, sorgt dieser „Priming” Prozess für eine reproduzierbar Lufteinschluss-freie Befüllung des Durchflusssystem.
• • Das Bewegen eines nicht mischbaren zweiphasigen Flüssigkeitskörpers erlaubt ein exaktes Befüllen von Kavitäten, da der Fluidfluss nach Passage des Anteils der ersten Flüssigkeit an einem kühl geschalteten Ventilpunkt zum Erliegen kommt. Dies erlaubt ohne aufwendige Messverfahren bzw. online-Fluidflusskontrollen im Durchflusssystem ein exaktes Abmessen der bewegten Flüssigkeitsmenge.

The valve technology described overcomes several disadvantages of the prior art and solves various problems of wax-based valve technology. In summary, the following advantages are achieved:

• • The closing temperature (channel filling temperature) of the fluid-filled channel is independent of the aqueous analysis buffer used, making it more manageable and easier to validate with micro-flow systems equipped with it.
• • The closing temperature is considerably higher than that of ice valves (in any case above 0 ° C), which allows a faster closing of the channel.
• • The heat capacity of the phase transition is at least 30% lower than in the water-ice transition, which also means that the phase change can be faster than with water.
• • The valve according to the invention can be switched as often as desired, since the channel to be switched can always be filled with a second liquid side.
• • The technical effort required to open and close a valve is considerably lower than conventional valve technology with valve bodies and servomotors. It is also less than the effort to control, for example, twice switchable wax valves according to the prior art.
• • The production costs are considerably lower, as it is not necessary to introduce wax into the valve area in the production process, as is absolutely necessary with conventional wax valves.
• The microfluidic flow-through system is in particular filled with the second fluid before it is filled with a first fluid. If the second fluid is a highly wetted fluid, this "priming" process provides for a reproducible air entrapment-free filling of the flow system.
• • Moving an immiscible biphasic fluid body allows accurate filling of cavities as fluid flow stops upon passage of the first fluid portion at a cool valve point. This allows a precise measurement of the amount of liquid moved without complex measuring methods or online fluid flow controls in the flow system.

Insofar as advantages and method steps have been described on the example of pentadecane and aqueous liquid, these advantages and method steps can also be achieved with other pairs of liquids which behave comparably to one another, ie in particular are not miscible with one another.

The first liquid can be dispersed in the second liquid. If a proportion of the second liquid is transported in a controlled manner within the throughflow system, then the fraction of the first liquid dispersed therein is likewise transported in a correspondingly controlled manner. It is thus possible to use the second liquid to transport portions of the first liquid in a controlled manner.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7144616 B1 [0002]
• JP 2006183818 A [0007]
• US 6981518 B2 [0007]
• US 6981151 B2 [0007]
• US 2008/0056949 A1 [0009]
• US 2008/0112855 A1 [0009]
• US 2007/0227592 A1 [0009]
• US 2007/0231216 A1 [0009]
• US 2004/0007275 A1 [0009]
• US 2008/0314465 A1 [0009]
• US 2005/0247356 A1 [0009]
• US 2005/0247357 A1 [0009]

Cited non-patent literature

• Robin Hui Liu, Jianing Yang, Ralf Lenigk, Justin Bonanno, and Piotr Grodzinski: Self-Contained, Fully Integrated Biochip for Sample Preparation, Polymerase Chain Reaction Amplification, and DNA Microarray Detection, Anal. Chem. 2004, 76, 1824-1831 [0005]
• R. Pal et al .: An integrated microfluidic device for influenza and other genetic analyzes, Lab Chip, 2005, 5, 1024-1032 [0005]
• Chunsun Zhang et al., Micropumps. Microvalves and micromixers within PCR microfluidic chips: Advances and trends, Biotechnology Advances 25 (2007) 483-514, Elsevier [0007]
• J. Micromech. Microeng. 16 (2006) R13-R39, A review of microvalves, Kwang W Oh et al. [0007]
• Yan He et al .: Capillary-based Fully Integrated and Automated System for Nanoliter Polymerase Chain Reaction Analysis Directly From Cheek Cells, Journal of Chromatography A, 924 (2001) 271-284 [0009]
• P. Selvaganapathy *, ET Carlen, CH Mastrangelo: Electrothermally Actuated Inline Microfluidic Valve, Sensors and Actuators A 104 (2003) 275-282 [0009]
• Lena Klintberg et al .: Fabrication of a paraffin actuator using hot embossing of polycarbonates, Sensors and Actuators A 103 (2003) 307-316 [0009]
• Robin Hui Liu, Jianing Yang, Ralf Lenigk, Justin Bonanno, and Piotr Grodzinski: Self-Contained, Fully Integrated Biochip for Sample Preparation, Polymerase Chain Reaction Amplification, and DNA Microarray Detection, Anal. Chem. 2004, 76, 1824-1831 [0009]
• R. Pal et al .: An integrated microfluidic device for influenza and other genetic analyzes, Lab Chip, 2005, 5, 1024-1032 [0009]
• Zongyuan Chen, Jing Wang, Shizhi Qian and Haim H. Construction: Thermally-actuated, phase change flow control for microfluidic systems, Lab Chip, 2005, 5, 1277-1285 [0009]
• Myriam Vincent, Van Xu & Huimin Kong, Helicase-dependent isothermal DNA amplification, EMBO reports VOL 5, NO 8, 2004, p. 795 [0030]
• Olaf Piepenburg, Colin H. Williams, Derek L. Stemple, Niall A. Armes, DNA Detection Using Recombination Protein, PLoS Biology, July 2006, Volume 4, Issue 7, e204 [0030]
• Effrey Van Ness, Lori K. Van Ness, and David J. Galas, Isothermal Responses to the Amplification of Oligonucleotides, 4504-4509, PNAS, April 15, 2003, Vol. 8 [0030]

Claims (11)

Method for controlling the transport of a first, in particular aqueous, liquid in a flow-through system ( 1 . 2 . 3 ), in particular in a micro flow system according to which the control of the transport of the first liquid in the flow system by means of a second liquid, in particular pentadecane, wherein the first liquid is immiscible with the second liquid and the flow-through system at least partially flooded with the second liquid becomes. Method according to claim 1, characterized in that a chamber ( 1 ) of the micro-flow system is filled with the second liquid and then the first liquid via a feeding channel ( 2 ) into the chamber filled with the second fluid ( 1 ) is pumped. A method according to any one of the preceding claims, wherein the first liquid is an aqueous mixture for carrying out a PCR. Method according to one of the preceding claims, in which the transport of a first liquid is controlled by solidifying or liquefying the second liquid. A method according to any one of the preceding claims, wherein the temperature at which the first liquid stops flowing is lower than the temperature at which the second liquid ceases to flow. Method according to one of the preceding claims, in which an area ( 11 ) of the flow system ( 1 . 2 . 3 ) is cooled to a temperature at which the second liquid stops flowing, a first liquid is transported by means of the second liquid, and the transport of the first liquid is stopped by passing the second liquid into the cooled region and solidifies. Method according to one of the preceding claims, in which the first liquid within the flow-through system ( 1 . 2 . 3 ) is pumped by the second liquid is pumped into an area of the flow system in which the first liquid is located. Flow system, in particular micro flow system ( 1 . 2 . 3 ) comprising tetradecane, pentadecane or hexadecane for controlling the transport of a liquid within the flow-through system. Flow-through system according to the preceding device claim comprising means for cooling and / or heating the tetradecane, pentadecane or hexadecane. Flow system according to one of the preceding device claims comprising heating and cooling means for carrying out a PCR and in particular a Peltier element. Flow-through system according to one of the preceding device claims comprising one or more reagents for performing an analysis or a PCR.

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