Method and apparatus for reducing sample dispersion in turns and junctions of microchannel systems

• US 6,733,730 B1
• Filed: 11/06/2000
• Issued: 05/11/2004
• Est. Priority Date: 04/26/1999
• Status: Expired due to Term

• Current Assignee: National Technology & Engineering Solutions Of Sandia LLC (Honeywell International Inc.)
• Original Assignee: Sandia Corporation (Martin Marietta Corporation)
• Inventors: Nilson, Robert H., Griffiths, Stewart K.
• Primary Examiner(s): NOGUEROLA, ALEXANDER STEPHAN
• Application Number:
  US09/707,337
• Time in Patent Office: 1,282 Days
• Field of Search: 422/70, 422/99, 422/100, 422/129, 422/50, 422/81, 204/400, 204/451, 204/600, 204/601
• US Class Current: 422/502
• CPC Class Codes: B01F 2101/23 Mixing of laboratory samples e.g. in preparation of analysing or testing properties of materials
• CPC Class Codes: B01F 25/31 in conduits or tubes through which the main component flows
• CPC Class Codes: B01F 25/433 Mixing tubes wherein the shape of the tube influences the mixing, e.g. mixing tubes with varying cross-section or provided with inwardly extending profiles
• CPC Class Codes: B01F 25/4331 Mixers with bended, curved, coiled, wounded mixing tubes or comprising elements for bending the flow
• CPC Class Codes: B01F 25/4335 Mixers with a converging-diverging cross-section
• CPC Class Codes: B01F 33/30 Micromixers
• CPC Class Codes: B01J 19/0093 Microreactors, e.g. miniaturised or microfabricated reactors laboratory containers with capillary fluid transport in microfabricated channels or chambers B01L3/5027
• CPC Class Codes: B01J 2219/00828 Silicon wafers or plates
• CPC Class Codes: B01J 2219/00831 Glass
• CPC Class Codes: B01J 2219/00833 Plastic
• CPC Class Codes: B01J 2219/00853 Employing electrode arrangements
• CPC Class Codes: B01J 2219/00912 by electrophoresis
• CPC Class Codes: B01J 2219/00916 by chromatography
• CPC Class Codes: B01J 2219/00957 Compositions or concentrations
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2400/0415 electrical forces, e.g. electrokinetic
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 2400/084 Passive control of flow resistance
• CPC Class Codes: B01L 3/502746 characterised by the means for controlling flow resistance, e.g. flow controllers, baffles B01L3/502738 takes precedence
• CPC Class Codes: G01N 2030/285 electrically driven carrier
• CPC Class Codes: G01N 27/44791 : Microapparatus sample containers with integrated microfluidic structures B01L3/5027
• CPC Class Codes: G01N 30/6065 : with varying cross section
• CPC Class Codes: G01N 30/6086 : form designed to optimise dispersion
• CPC Class Codes: G01N 30/6095 : Micromachined or nanomachined, e.g. micro- or nanosize
• CPC Class Codes: Y10S 366/02 : Micromixers: segmented laminar flow with boundary mixing orthogonal to the direction of fluid propagation with or without geometry influences from the pathway
• CPC Class Codes: Y10S 366/03 : Micromixers: variable geometry from the pathway influences mixing/agitation of non-laminar fluid flow

Abstract

What is disclosed pertains to improvement in the performance of microchannel devices by providing turns, wyes, tees, and other junctions that produce little dispersion of a sample as it traverses the turn or junction. The reduced dispersion results from contraction and expansion regions that reduce the cross-sectional area over some portion of the turn or junction. By carefully designing the geometries of these regions, sample dispersion in turns and junctions is reduced to levels comparable to the effects of ordinary diffusion. The low dispersion features are particularly suited for microfluidic devices and systems using either electromotive force, pressure, or combinations thereof as the principle of fluid transport. Such microfluidic devices and systems are useful for separation of components, sample transport, reaction, mixing, dilution or synthesis, or combinations thereof.

Claims

1. A low-dispersion microchannel device for dividing a sample comprising:

a branching junction having one inlet end and at least two outlet ends, an inner wall and an outer wall, at least one contraction region, at least one constricted region, and at least one expansion region, wherein a portion of the constriction region has a cross-sectional area that is smaller than that of at least one outlet end, and wherein the branching junction has a cross-section that is rectangular, trapezoidal, or triangular.

2. The low-dispersion microchannel device of claim 1, wherein the branching junction has a cross-section that is rectangular.

3. The low-dispersion microchannel device of claim 1, wherein the branching junction has a cross-section that is trapezoidal.

4. The low-dispersion microchannel device of claim 1, where the branching junction has a cross-section that is triangular.

5. A low-dispersion microchannel device for joining two or more sub-samples comprising:

a confluence junction having two or more inlet ends and one outlet end, an inner wall and an outer wall, at least one contraction region, at least one constricted region, and at least one expansion region, wherein a portion of the constriction region has to a cross-sectional area that is smaller than that of at least one inlet end, and wherein the confluence junction has a cross-section that is rectangular, trapezoidal, or triangular.

6. The low-dispersion microchannel device of claim 5, wherein the confluence junction has a cross-section that is rectangular.

7. The low-dispersion microchannel device of claim 5, wherein the confluence junction has a cross-section that is trapezoidal.

8. The low-dispersion microchannel device of claim 5, wherein the confluence junction has a cross-section that is rectangular.

9. A low-dispersion device for turning the direction of transport of a moving sample that comprises:

a microchannel system comprising at least one turning channel having an inlet end and an outlet end, an inner wall and an outer wall, and an included turn angle, wherein the turning channel comprises contraction and expansion regions such that a portion of the turning channel is constricted to a width that is smaller than the widths of the inlet and the outlet ends, wherein the contraction and expansion regions define inner and outer walls of the turning channel that differ in length by less than the product of the included turn angle and the larger of the widths of the turning channel at the inlet end and outlet end.

10. A low-dispersion device for dividing a sample that comprises:

a planar substrate patterned to define a microchannel system comprising at least one branching junction having one inlet end and at least two outlet ends, an inner wall and an outer wall, at least one contraction region, at least one constricted region, and at least one expansion region, wherein the constriction region has a width that is smaller than the width of at least one outlet end.

11. The low-dispersion device of claim 10 having one inlet end and two outlet ends wherein the sum of the widths of the two outlet ends is substantially equal to the width of the inlet end.