Microscale diffusion immunoassay in hydrogels

• US 20060115905A1
• Filed: 06/23/2005
• Published: 06/01/2006
• Est. Priority Date: 03/29/1996
• Status: Abandoned Application

• Current Assignee: University of Washington
• Original Assignee: University of Washington
• Inventors: Yager, Paul, Hatch, Anson
• Application Number:
  US11/165,619
• Publication Number:
  US 20060115905A1
• Time in Patent Office: Days
• US Class Current: 436/517
• CPC Class Codes: B01F 25/31 in conduits or tubes through which the main component flows
• CPC Class Codes: B01F 33/30 Micromixers
• CPC Class Codes: B01F 33/3039 with mixing achieved by diffusion between layers
• 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: B01L 2300/0822 Slides
• CPC Class Codes: B01L 2400/0472 Diffusion
• 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: G01N 15/10 Investigating individual particles
• CPC Class Codes: G01N 15/14 Optical investigation techniques, e.g. flow cytometry
• CPC Class Codes: G01N 30/0005 Field flow fractionation
• CPC Class Codes: G01N 30/38 Flow patterns
• CPC Class Codes: G01N 30/6095 Micromachined or nanomachined, e.g. micro- or nanosize
• CPC Class Codes: G01N 30/74 Optical detectors measurement of intensity, velocity, spectral content, polarisation, or phase of infrared, visible or ultraviolet light G01J
• CPC Class Codes: G01N 33/54313 the carrier being characterised by its particulate form
• CPC Class Codes: G01N 33/558 using diffusion or migration of antigen or antibody immunochromatographic test strips G01N33/54387
• CPC Class Codes: G01N 35/085 Flow Injection Analysis

Abstract

A diffusion immunoassay (DIA) for determining the presence and concentration of analyte particles by detecting the diffusion front. A hydrogel containing immobilized binding particles is placed in contact with a carrier fluid containing analyte particles, which analyte particles diffuse into the hydrogel and bind with the immobilized binding particles. A detection device detects the position of the diffusion front formed in the hydrogel to determine the presence and concentration of the analyte particles which have diffused into the hydrogel.

Claims

1. A method for detecting the presence of analyte particles contained in a carrier allowing diffusion of said analyte particles, and method comprising the steps of:

a.) providing binding particles capable of binding with analyte particles;

b.) substantially immobilizing said binding particles in a hydrogel which permits diffusion of analyte particles;

c.) placing a carrier containing analyte particles in contact with said hydrogel;

d.) allowing said analyte particles to diffuse from said carrier into said hydrogel and bind with said binding particles;

e.) providing a detection device for detecting said binding particles or said analyte particles, or complexes thereof, or a diffusion front created by any of said particles;

and f.) detecting the position of any of said particles or diffusion front as an indication of the presence of said analyte particles.

2. The method of claim 1, wherein said diffusion front is detected at a predetermined time after initiating diffusion within the system.

3. The method of claim 1, wherein said binding particles are antibodies, proteins, DNA, or enzymes.

4. The method of claim 1, wherein said hydrogel is acrylamide.

5. The method of claim 1, wherein said analyte particles are supplemented with labeled analyte particles.

6. The method of claim 4, wherein said hydrogel comprises a solid.

7. The method of claim 1, wherein said detecting step comprises comparisons of the position of the diffusion front with the position of a diffusion front in a calibration system.

8. The method of claim 1, wherein said binding particles are labeled.

9. The method of claim 1, wherein said detection device is a CCD camera.

10. A microscale device for determining the presence or concentration of sample analyte particles, said device comprising:

a first section containing a carrier fluid containing analyte particles,

a second section containing a hydrogel in contact with said carrier fluid containing binding particles immobilized within said hydrogel which are capable of binding with analyte particles;

and a detection device for detecting a diffusion front formed by said analyte particles which have diffused into said hydrogel.

11. The device of claim 10, wherein said hydrogel is acrylamide.

12. The device of claim 10, wherein said detection device comprises a CCD camera.

13. The device of claim 10, further comprising means, coupled to said detection device, for determining from said detected diffusion front the presence or concentration of analyte particles.

14. The device of claim 10, wherein the area of contact between said hydrogel and said carrier fluid comprises approximately 2500 μ

m².

15. The device of claim 10, wherein the area of contact between said hydrogel and said carrier fluid is rectangular.