DE102009041325A1 - Microvalve unit for shifting channels in microflow systems, comprises mechanically stiff, plane parallel molded body, which has one or multiple micro channels, which are provided with inlets and outlets - Google Patents

Abstract

The microvalve unit (1) comprises a mechanically stiff, plane parallel molded body (2), which has one or multiple micro channels, which are provided with inlets and outlets. A shifting area is provided, which has the shifting ends of the micro channels in a concentric position arrangement. Another molded body (3) is provided, which meshes in the shifting area of the former molded body. The former molded body comprises a manifold made of glass and silicon pile, glass and glass pile or a polymer and polymer pile. The latter molded body is made of polydimethylsiloxane.

Description

The The invention relates to a microvalve unit for switching channels in microfluidic systems.

in the State of the art are numerous microvalves for use in microfusion systems known. These are essentially diaphragm valves with a piezoelectric actuator, a thermal-electric drive or with a pneumatic actuator.

So revealed the EP 1 331 997 B1 a microfluidic flow control device in which an elastic membrane is deformed by a pressure difference between two channel segments such that a channel segment is closed.

In the EP 1 633 988 B1 a microflute unit is described with electrical opening control in which by increasing the temperature of a thermosensitive material is deformed, whereby the spatial separation of microchannels is repealed and thus communication between the microchannels is possible.

Of the Disadvantage of these microvalves is that when opening and closing the valves fluid displacement is caused, resulting in a volume change within the microchannels expresses. This comes to short-term pressure peaks within the microchannel and to fluid displacements. This effect is especially related to biological Applications significant in which a time-dependent investigation of cells in microfluidic systems by means of a microscope.

The DE 101 57 317 A1 shows a basic element of a microfluidic processor, in which an actuator based on a swellable polymer network with volume phase transition behavior (hydrogel) is arranged. With such hydrogels, a displacement-free transition of liquids can be realized. The liquid is first stored in the hydrogel, whereby a closure of the channel is possible. In the case of a thermally switchable hydrogel, a switching process can be brought about by increasing the temperature, which releases the bound liquid from the hydrogel. This results in no overall volume change but only a change in the state of the liquid from a bound to a volatile form. The thus discharged liquid can then escape from the chamber, for example via pores.

Of the Disadvantage when using hydrogels for displacement-free Liquid transfer exists mainly in the necessary temperature change for switching the hydrogels, the consequent long switching times, the low tolerance Press in the microflow system as well as in the restricted chemical resistance of the hydrogels.

Farther rotary valves for syringe pumps are known, such as on the Cavro XL 3000 Modular Digital Pump (Tecan Systems, San Jose, CA), which provides a volume displacement free circuit between allow different channels. In this case, the fixed Stator numerous fluid access holes and the rotor a channel in an angled or rectilinear form, according to the circuit make a connection between the fluid access holes of the stator can. This is achieved in the form of a rotary movement. Rotor and stator are usually as slightly conical, rotationally symmetric Formed body, which rotate against each other to let. Typical combination of materials for stator / rotor moldings are PCTFE / PTFE (polychlorotrifluoroethylene / polytetrafluoroethylene), Ceramic / PTFE and ceramic / ceramic, as these rotary valves use in Find high pressure area.

Of the Disadvantage of these rotary valves is mainly that this solution not for integration into "lab-on-chip" microsystems suitable is.

The Object of the present invention is therefore a microvalve unit to provide for switching channels in microfluidic systems, the resulting disadvantage by volume displacement when switching overcomes and at the same time for the use as an integrated component in microfluidic channel systems suitable is.

The Task is by micro valve unit for switching channels in microfluidic systems according to the features of Claim 1 solved. Other embodiments go from the the dependent claims.

According to the invention, two planar shaped bodies are used, one of which forms a first mechanically rigid, plane-parallel shaped body with a micro-channel micro-channel system which has one or more microchannels which have inputs and outputs and open into a switching area, this switching area having to be connected channel ends in a concentric position arrangement and a second molded body which engages in the switching region of the first molded body, which has one or more microchannels in the contact area to the first molded body, wherein the second molded body is attached to a further rotationally symmetrical shaped body by a joining method and wherein this rotationally symmetrical shaped body is in engagement with a drive unit, which rotati allowed onsbewegung the rotationally symmetrical shaped body and wherein this rotationally symmetrical shaped body is pressed by a spring element on the first molded body, wherein a positive connection of the first and second molded body is formed. This allows volume displacement-free switching in the microfluidic system, thereby avoiding short term pressure spikes within the microchannel and resulting fluid displacements.

According to the Invention is for switchable connection of the microchannels of the first shaped body a defined rotation of the rotationally symmetrical shaped body by means of the drive unit, wherein a fluidically sealed connection the microchannels of the first molded body with the Micro channel of the second molded body is formed. By accordingly defined rotational movement of the second molded body is a volume displacement free Connection between the microchannels of the first molded body produced.

In an embodiment of the invention, there is the first molded body from a solid body in the hole area planparalleler and polished surface.

In Another embodiment of the invention is the first Shaped a Manifold, which optionally as glass-silicon Stack or stack as a glass-glass stack or as a polymer-polymer stack can.

In an embodiment, the first molded body molded with a silicone rubber from a silicon master.

In In another embodiment, the first molded body from a PDMS molded body produced by molding (PDMS short for poly-dimethylsiloxane).

In Another embodiment is the second molded body molded with a silicone rubber from a silicon master.

In According to one embodiment, the second shaped body, which engages in the first molded body, from a through Abformtechnik produced PDMS sealing piece, which by means of Spring element on the planar first molded body with channel inlet openings is pressed and defined by a suitable drive element can be twisted. For the production of the PDMS sealing piece First, an inverted channel structure in the silicon master microfabricated. Subsequently, the PDMS sealing piece directly on a rotationally symmetrical shaped body by means Impression technique, injection molding technique, hot stamping technique or Imprinttechnik be applied so that an optimal fit for elastic sealing piece is guaranteed and thus this Sealing piece without torsional distortion in a relative movement, a rotation or displacement, can be offset. The rotationally symmetrical shaped body in turn is engaged with a drive element which the Realized rotational movement.

Either the first and the second molded body can consist of PDMS. Leave by using the impression technology elaborate fine structures in reproducible Create fashion. Through the use of silicon master structures is a reproducible production of the first and second shaped body possible. This allows individual components the microvalve unit in case of possible signs of wear be easily replaced.

In In another embodiment, the second molded body integrated with spring element in a standardized connection fitting and the drive is equipped with a position encoder. This allows the Actuating motion reproducible for the execution of Microfluidic switching operations without volume displacement be used.

In Further embodiments, the drive unit with an electromagnetic Drive means, with a pneumatic drive means or a connected to hydraulic drive means.

In Another embodiment, the in the first molded body engaging side of the second molded body by sputtering or other suitable processes in the range of a few nanometers. By coating with metal becomes the resistance of the second molded body increases.

In In another embodiment, the injection volume by time-dependent contacting of the microchannels determined as a result of the switching process.

For the case of using the microvalve as an injector may be the injector volume by the geometry of the molded second shaped body and the dynamics of the switching process can be specified.

The Advantages of this microvalve unit are its robustness, its Switching speed, the excellent chemical resistance, Sterilizability, variability from valve to more complex microfluidic injector and the small footprint at the switching point of the microfluidic system.

The invention will be explained in more detail with reference to embodiments. The accompanying drawings show in

1 a schematic representation of the cross section of the microvalve unit according to the invention with spring element and drive unit;

2 a schematic representation of the switching operation of the microvalve unit;

3 an exploded view of the microvalve unit according to the invention.

The microvalve unit 1 as they are in 1 is shown, consists of a first and a second shaped body 2 . 3 , The molded body 2 contains a microfluidic system of a silicon glass stack, which has a plurality of switchable microchannels K1, K2. The micro-channels K1, K2 of the silicon-glass molded body to be connected 2 , also referred to as silicon-glass manifold, open in a rotationally symmetrical arrangement in a switching range S.

Geometrically suitable for this shift range S sits the second molded body 3 made of PDMS (polydimethylsiloxane) as a rotatable sealing piece on the molding 2 with the microchannels K1, K2 and centric over the switching range S.

It is understood that instead of the two illustrated microchannels K1, K2 and other microchannels in a corresponding rotationally symmetrical arrangement in the Förmkörper 2 can lead to the switching area.

The molded body 3 consists of PDMS (polydimethylsiloxane), itself contains one or more microchannels MK and is directly attached to the shaft 4 appropriate. The geometric relationship of the microchannel MK in the second molding 3 (Sealing) to the channel mouths in the switching area S are carried out so that the molding 3 depending on the angular position microchannels K1, K2 through the microchannel system in the molding 2 free, or these micro channels K1, K2 fluidly sealed.

In 2a , c is the micro-channel K2 released and the micro-channel K1 locked and in 2 B , D is the micro-channel K1 released and the micro-channel K2 locked.

This is the second molding 3 on a shaft via a rotationally symmetrical shaped body 4 applied by means of impression technique, injection molding technique, hot stamping technique or imprint technique. This rotationally symmetrical shaped body 4 allows the optimal fit to the elastic molded body 3 with the microchannel MK and in turn is in engagement with the drive 6 , which by means of pneumatic or electromagnetic or hydraulic drive means, a rotational movement of the rotationally symmetrical shaped body 4 and thus of the sealing piece 3 allowed. This rotational movement leads to contacting the microchannel of the sealing piece 3 with the microchannels K1, K2 in the first molded body 2 , By a suitable spring element 5 becomes a positive and non-positive connection between the first and second moldings 2 . 3 guaranteed over the entire period of use.

The microvalve unit according to the invention 1 can be used to control the injection volume. For this purpose, a time-dependent circuit of the microvalve unit 1 between several microchannels K1, K2. In 2a , c is a first shaped body 2 shown with four channels, each consisting of two sub-channels K1 and K2, each with two sub-channels K1; K2 opposite and thus form a channel pair, which through the microchannel MK of the sealing piece 3 can be connected to each other. By rotation of the rotationally symmetrical shaped body 4 there is a rotation of the shaped body 3 , whereby a connection of a channel pair K2 takes place. By re-rotating according to 2 B , d is a volume displacement free contacting of the second channel pair K1. By appropriate variation of the contacting time, a control of the injection volume is possible. By volume displacement-free contacting while accurate application of the desired injection volume is possible. An example of a realizable injection volume shows the resulting flow 7 in 2d ,

3 shows an exploded view of the central assembly of the inventive microvalve unit 1 containing the rotationally symmetrical shaped body 4 molded second molded body 3 as well as the spring 5 for generating the contact force between the first and the second shaped body. The molded body 4 is in a housing 12 via a coupling piece 11 in a warehouse 10 with another coupling piece 9 coupled, which in turn connects to the drive 6 manufactures.

The drive 6 is still with an encoder 8th for determining the angular position of the second shaped body 3 Mistake.

It is also possible to use the surface of the PDMS sealing piece 3 , which with the fitting 2 comes in contact with a metal, such as gold or other suitable metal to coat. This coating in the range of a few nanometers, for example, by means of sputtering, although other suitable methods for metallic coating can be used. This coating causes a reduction in wear of the sealing piece, which can occur over time in accordance with frequent switching.

1

Micro valve unit

2

first Shaped body with microfluidic system

3

second Shaped body (PDMS sealing piece)

4

rotationally symmetrical moldings

5

feather for pressing the PDMS sealing piece

6

drive

7

resulting River

8th

encoder for position detection

9

coupling above

10

camp above

11

coupling below

12

casing

K1

microchannel

K2

microchannel

S

switching range

MK

microchannel

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 1331997 B1 [0003]
• - EP 1633988 B1 [0004]
• - DE 10157317 A1 [0006]

Claims (16)

Microvalve unit ( 1 ) for switching channels in microfluidic systems, comprising - a first mechanically rigid, plane-parallel shaped body ( 2 ), which has one or more microchannels (K1, K2), which have inputs and outputs and open into a switching region (S), said switching region (S) to be connected ends of the microchannels (K1, K2) in a concentric Having a layer arrangement, - and a second molded body ( 3 ), which in the switching region (S) of the first molded body ( 2 ), which in the contact area to the first molded body ( 2 ) has one or more microchannels (MK), - wherein the second shaped body ( 3 ) to a rotationally symmetrical shaped body ( 4 ) is attached by joining method, - and wherein this rotationally symmetrical shaped body ( 4 ) with a drive unit ( 6 ) is engaged, which a rotational movement of the rotationally symmetrical shaped body ( 4 ) and - whereby this rotationally symmetrical shaped body ( 4 ) non-positively on the first molded body ( 2 ) is pressed, wherein a positive connection of the first ( 2 ) and second ( 3 ) Formed body. Microvalve unit according to claim 1, characterized in that for connecting the microchannels (K1, K2) of the first shaped body ( 2 ) a defined rotation of the rotationally symmetrical shaped body ( 4 ) by means of the drive unit ( 6 ), whereby a fluidically tight connection of the microchannels (K1, K2) of the first shaped body ( 2 ) with the microchannel (MK) of the second shaped body ( 3 ) can be produced. Microvalve unit according to claims 1 and 2, characterized in that the first shaped body ( 2 ) consists of a solid body in the switching area (S) plane-parallel and polished surface. Microvalve unit according to claims 1 to 3, characterized in that the first shaped body ( 2 ) a manifold consists of a glass-silicon stack, a glass-glass stack or a polymer-polymer stack. Microvalve unit according to claims 1 to 3, characterized in that the first molded body ( 2 ) is molded with a silicone rubber from a silicon master. Microvalve unit according to claim 5, characterized in that the first shaped body ( 2 ) consists of PDMS (polydimethylsiloxane). Microvalve unit according to claims 1 to 5, characterized in that the second shaped body ( 3 ) is molded with a silicone rubber from a silicon master. Microvalve unit according to claim 7, characterized in that the second shaped body ( 3 ) consists of PDMS (polydimethylsiloxane). Microvalve unit according to one of claims 5 to 8, characterized in that both the first ( 2 ) as well as the second shaped body ( 3 ) consist of PDMS (polydimethylsiloxane). Microvalve unit according to one of claims 1 to 9, characterized in that the drive unit ( 6 ) is connected to a pneumatic, electromagnetic or hydraulic power source. Microvalve unit according to one of claims 1 to 10, characterized in that the second molded body ( 3 ) in the contact region to the first shaped body ( 2 ), in particular in the switching region (S) has a coating with a metal. Microvalve unit according to claim 11, characterized in that the second shaped body ( 3 ) is provided with a sputtered coating. Microvalve unit according to one of claims 1 to 12, characterized in that the injection volume by time-dependent contacting of the microchannels as a result the switching operation is predetermined. Microvalve unit according to one of claims 1 to 13, characterized in that the second molded body ( 3 ) to the rotationally symmetrical shaped body ( 4 ) is applied by means of impression technique, injection molding technique, hot stamping technique or imprint technique. Use of the microvalve unit according to one of claims 1 to 14, characterized in that the specification of the injector volume by the geometry of the molded second molded body ( 3 ) in conjunction with the dynamics of the switching process takes place. Microvalve unit according to claim 15, characterized in that that the injector volume is determined by the number and speed of the Switching operations is determined.