Method for connecting components of a microfluidic flow cell

Abstract

A flow cell and a method for connecting components of a microfluidic flow cell, in particular for integrating component parts into a carrier structure of the flow cell, in which a gap is formed between the components to be connected. The gap is filled with a solvent. The material of at least one component bordering the gap dissolves in the solvent and the material completely fills the width of the gap and partially fills the height thereof after evaporation of the solvent.

Claims

1. A microfluidic flow cell, comprising: a carrier structure having a pocket having a bottom with an opening; a component arranged in the pocket at a distance from a wall of the pocket so as to form a gap between an entire outer surface of the component and the wall, the gap having a bottom formed by the bottom of the pocket and an opening opposite the bottom; and a connection structure obtained by dissolving material from at least one of the component and the carrier structure by a solvent in the gap and settling of the material from the solvent toward the bottom gap as a result of evaporation of the solvent through the opening, wherein the connection structure is formed by settled material that completely fills the gap from the bottom of the gap up to at least a portion of a height of the gap, wherein the connection structure has a layered configuration.

2. The flow cell according to claim 1, wherein the material is an amorphous plastic.

3. The flow cell according to claim 2, wherein the amorphous plastic is one of the group consisting of PMMA, PC, PS, COC, and COP.

4. The flow cell according to claim 1, wherein the gap is an annular gap that surrounds the component.

5. The flow cell according to claim 1, wherein the component rests in the pocket of the carrier structure on a ring-shaped shoulder or on the bottom of the pocket closing off the gap on one axial side.

6. The flow cell according to claim 1, wherein the ring-shaped structure is a punched film connected to the carrier structure.

7. The flow cell according to claim 5, wherein the ring-shaped shoulder or the bottom of the pocket comprises a surface structured so that an additional gap area connected to the gap is formed between the carrier structure and the component resting on the ring-shaped shoulder or on the bottom of the pocket.

8. The flow cell according to claim 5, wherein the component comprises a surface on a side facing the ring-shaped shoulder, the surface having functional groups attached thereon.

9. The flow cell according to claim 5, wherein the component comprises strip conductors on a side facing the ring-shaped shoulder.

10. The flow cell according to claim 9, wherein the strip conductors of the component are in contact with a strip conductor that extends to the component and is connected to the carrier structure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a first exemplary embodiment of a flow call according to the invention produced by the connecting method according to the invention;

(2) FIG. 2 shows a second exemplary embodiment of a flow cell according to the invention with an extended connecting area;

(3) FIG. 3 shows a third exemplary embodiment of a flow cell according to the invention with a carrier structure formed out of a plastic plate and a film;

(4) FIG. 4 shows a fourth exemplary embodiment of a flow cell according to the invention, which, in contrast to the exemplary embodiment of FIG. 3, also comprises electrical strip conductors;

(5) FIG. 5 shows a fifth exemplary embodiment of a flow cell according to the invention with strip conductors and conductor pins; and

(6) FIGS. 6-10 show additional exemplary embodiments of flow cells according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(7) A microfluidic flow cell as shown partially in FIG. 1 comprises a plate-shaped carrier structure 1, which consists preferably of an amorphous plastic such as PMMA, PC, PS, COC, or COP.

(8) A microcomponent 3—in the example shown, a component with the basic form of a circular disk or a square plate—is arranged in a pocket 2 of the carrier structure 1. The microcomponent is preferably made of silicon, but it can also be formed out of metal, ceramic, plastic, or glass with a surface which can be functionalized in various ways.

(9) The microcomponent 3 rests on a ring-shaped shoulder 4 of the pocket 2; except for this shoulder, the pocket passes straight through the entire thickness of the carrier structure 1. An annular gap 5, formed between the carrier structure 1 and the microcomponent 3, is open on one axial side, whereas, on the other axial side, it is closed off by the ring-shaped shoulder 4 of the carrier structure 1. The width 3 of the annular gap 5 is typically in the range of 0.01-0.1 mm.

(10) According to FIG. 1b, the annular gap 5 is partially filled with plastic material 6. The plastic material 6 bridging the width of the annular gap 5 is the same as the material of which the carrier structure 1 consists. During the evaporation of a solvent 7, introduced into the annular gap as shown in FIG. 1a, this material settles out, thus filling up the annular gap 5.

(11) The solvent 7 dissolves some of the carrier structure 1, so that the plastic material 6 which has settled out of the evaporated solution consists at least partially of material removed from the carrier structure 1. Material of this kind can already be dissolved in the solvent 7, however, even before the solvent is introduced into the annular gap 5.

(12) Different solvents can be used depending on the plastic out of which the carrier structure is made. For PMMA plastic, an acetone-based solvent is suitable, for example; for PC plastic, an ethyl acetate-based solvent can be used; and for COC plastic, a toluene-based solvent can be used. The contact angles between such solvents and the plastic material of the carrier structure are typically less than 10°, which means that it is possible to fill very thin gaps by capillary action.

(13) The plastic material 6 which has become deposited in the annular gap 5 during the evaporation of the solvent 7 under the influence of gravity forms a fluid-tight bridge closing off the annular gap between the carrier structure 1 and the microcomponent 3; this bridge also produces a mechanically strong connection between these components. The amorphous plastic material settling out of the solution thus forms what in practice amounts to an integral part of the adjacent plastic of the carrier structure.

(14) It is obvious that additional filling and settling cycles can be carried out to fill the annular gap 5 with the plastic material 6 to an even greater extent.

(15) In the exemplary embodiment shown in FIG. 2, the ring-shaped shoulder 4 has a surface structure 8 of such a kind that a gap area forming a right-angled continuation of the annular gap 5 is formed; solvent 7 can also penetrate into this additional gap, which can thus be filled by resolidified plastic material 6. Capillary action stops abruptly at the inner edge of the ring-shaped shoulder 4, so that the capillary filling of the annular gap cannot proceed, and no solvent wets the bottom of the microcomponent outside the ring-shaped shoulder 4. A fluid-tight connection between the microcomponent 3 and the carrier structure 1 is thus also produced in the area of the ring-shaped shoulder 4. A surface structure 8 suitable for forming a gap continuation of this type can comprise a roughness of a defined type, grooves, webs, and/or local, possibly cylindrical, elevations, the end surfaces of which then form the support surface for the microcomponent.

(16) In the exemplary embodiment shown in FIG. 3, the ring-shaped shoulder 4 accommodating the microcomponent 3 is formed by a punched film 9. A plastic plate 10 and the film 9 together form the carrier structure 1, the film being bonded or welded to the plastic plate 10. The connection between the microcomponent 3 and the plastic plate 10 produced by the settled-out plastic material 6 also stabilizes the film 9, which is punched to form the ring-shaped shoulder 4. Because of the thinness of the film 9, there is the advantage that no dead volume is present in the area of the surface of the microcomponent 3 adjacent to the film 9; a dead volume which could, under certain conditions, have a negative effect on the testing of a fluid flowing past the microcomponent 3. The thickness of the film is preferably in the range of 0.01-0.2 mm.

(17) The plastic plate of the carrier structure 1 can be made of one of the same materials as those cited above for the carrier structure 1.

(18) Alternatively, the film 9 can be connected detachably to the microcomponent 3. Adhesive strips or tapes, for example, can be used to produce such a connection. After the annular gap 5 has been filled by the plastic material 6, these strips or tapes can be removed.

(19) An exemplary embodiment shown in FIG. 4 differs from the preceding example in that the microcomponent 3 is connected to strip conductors 11, which are in contact with strip conductors 12, which pass between the film 9 and the plastic plate 10. The width of the strip conductors can be in the range of 0.01-1 mm, and their thickness can be in the range of 0.01-10 μm. When the microcomponent 3 is integrated into the carrier structure 1 by the settling of the plastic material 6, the electrical contacts between the strip conductors 11 and 12 are also stabilized and fixed in place.

(20) In the exemplary embodiment of FIG. 5, the ring-shaped shoulder 4 is again formed as an integral part of the rest of the carrier structure 1, and strip conductors 11 connected to the microcomponent 3 are electrically in contact with conductor pins 13, which are perpendicular to the strip conductors 11 and pass through the ring-shaped shoulder 4. The permanent connection between the microcomponent 3 and the carrier structure 1 produced by the settled plastic material 6 also stabilizes the electrical contact between the strip conductors 11 and the conductor pins 13.

(21) According to FIG. 6, a fluid channel 18, which extends between the ports 14 and 15, is formed in the carrier structure 1, certain sections of this channel being bordered by films 16 and 17. The fluid channel 18 leads past a functionalized surface 19 of the microcomponent 3, which has been integrated into the carrier structure 1 by the settled plastic material 6.

(22) In contrast to FIG. 6, the functionalized surface 19 of the microcomponent 3 of FIG. 7 faces away from the side of the carrier structure 1 comprising the ports 14, 15.

(23) According to the exemplary embodiment of FIG. 8, a fluid channel 18 extends through a passage 20 in the microcomponent 3, as also in the case of the exemplary embodiment of FIG. 9, where the position of the microcomponent 3 is the reverse of that in FIG. 8.

(24) FIG. 10 pertains to a flow cell to be operated in the vertical position shown. It has a carrier structure 1 and another carrier structure 1′, which is connected to the carrier structure 1 by a film 21 through the use of adhesive bonding or welding, for example. An inlet 22 on the carrier structure 1′ is connected to a channel 23 possibly by way of several fluid-processing and preparation stations (not shown), which leads to a microcomponent 3 with a functionalized surface 19. Fluid introduced through the inlet 22 rises in the channel 23, wherein the air being displaced can escape through a vent opening 24.

(25) As the liquid level rises beyond the microcomponent 3, the fluid pressure being exerted on the microcomponent 3 integrated into the carrier structure 1 by settled plastic material 6 increases, so that very strict requirements are imposed on the leak-tightness of the connections. As a result of the integration obtained according to the invention, these requirements can be satisfied.

(26) While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.