Microfabricated diffusion-based chemical sensor

• US 20060073599A1
• Filed: 02/08/2005
• Published: 04/06/2006
• Est. Priority Date: 06/16/1995
• Status: Abandoned Application

• Current Assignee: University of Washington
• Original Assignee: University of Washington
• Inventors: Yager, Paul, Weigl, Bernhard H.
• Application Number:
  US11/054,711
• Publication Number:
  US 20060073599A1
• Time in Patent Office: Days
• US Class Current: 436/34
• CPC Class Codes: A61M 1/14 Dialysis systems; Artificial kidneys; Blood oxygenators semi-permeable membranes characterised by the material, manufacturing processes therefor B01D71/00; Reciprocating systems for treatment of body fluids, e.g. single needle systems for hemofiltration or pheresis
• CPC Class Codes: B01D 11/0492 Applications, solvents used
• CPC Class Codes: B01D 11/0496 by extraction in microfluidic devices
• CPC Class Codes: B01L 2200/0636 Focussing flows, e.g. to laminate flows
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0867 Multiple inlets and one sample wells, e.g. mixing, dilution
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• CPC Class Codes: B01L 3/502761 specially adapted for handling suspended solids or molecules independently from the bulk fluid flow, e.g. for trapping or sorting beads, for physically stretching molecules investigating characteristics of particles G01N15/00
• CPC Class Codes: B01L 3/502776 specially adapted for focusing or laminating flows
• CPC Class Codes: G01N 15/1484 microstructural devices
• CPC Class Codes: Y10T 436/25375 Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.]

Abstract

A channel-cell system is provided for detecting the presence and/or measuring the presence of analyte particles in a sample stream comprising: a) a laminar flow channel; b) two inlet means in fluid connection with said laminar flow channel for respectively conducting into said laminar flow channel (1) an indicator stream which may comprise an indicator substance which indicates the presence of said analyte particles by a detectable change in property when contacted with said analyte particles, and (2) said sample stream; c) wherein said laminar flow channel has a depth sufficiently small to allow laminar flow of said streams and a length sufficient to allow particles of said analyte to diffuse into said indicator stream to the substantial exclusion of said larger particles in said sample stream to form a detection area; and d) outlet means for conducting said streams out of said laminar flow channel to form a single mixed stream.

Claims

1. A microfluidic device comprising:

(a) a microfluidic channel having a first end and a second end; and

(b) means for simultaneously introducing at least two fluid streams into said first end of said channel;

whereby said streams flow in parallel laminar flow within said channel;

(c) said channel having a length sufficient to allow particles flowing in a first one of said streams to diffuse into a second of said streams to form a detection area.

2. The microfluidic device of claim 1 wherein said channel contains no internal structures.

3. The microfluidic device of claim 1 also comprising said first and second streams flowing in parallel laminar flow therein.

4. The microfluidic device of claim 3 wherein said first stream contains particles larger than said particles which diffuse into said second stream, which larger particles remain substantially in said first stream in said channel throughout the length of said channel.

5. The microfluidic device of claim 1 also comprising means for detecting said diffused particles in said second stream cooperatively connected with said channel.

6. A method for transporting particles across a fluid interface comprising:

(a) forming a fluid interface between two or more streams flowing within a microfluidic channel by;

(i) simultaneously flowing said streams into a laminar flow channel; and

(ii) allowing said streams to flow in side-by-side laminar flow within said channel; and

(b) allowing particles in a first of said streams to diffuse into a second of said streams.

7. The method of claim 6 wherein said streams are of equal volume.

8. The method of claim 6 wherein said streams are of equal flow rate.

9. The method of claim 6 comprising forming a fluid barrier between said streams.

10. The method of claim 9 wherein said fluid barrier is formed by flowing a greater volume of one stream than the other stream into said channel.

11. The method of claim 9 wherein the fluid barrier is formed by allowing a lesser volume of one stream that the other to exit said channel.

12. The method of claim 6 wherein said streams comprise a particle-containing stream and a particle-receiving stream, and particles contained in the particle-containing stream are allowed to diffuse into the particle-receiving stream.

13. The method of claim 6 wherein diffused particles are detected in said second stream.