Apparatus for performing assays on liquid samples accurately, rapidly and simply

• US 6,197,494 B1
• Filed: 03/18/1997
• Issued: 03/06/2001
• Est. Priority Date: 04/03/1987
• Status: Expired due to Fees

• Current Assignee: Cardiovascular Diagnostics, Inc. (PharmaNetics, Inc.)
• Original Assignee: Cardiovascular Diagnostics, Inc. (PharmaNetics, Inc.)
• Inventors: Oberhardt, Bruce
• Primary Examiner(s): Housel, James C.
• Assistant Examiner(s): RYAN, VERLENE J
• Application Number:
  US08/819,341
• Time in Patent Office: 1,449 Days
• Field of Search: 435/4, 435/792-795, 435/805, 435/810, 435/969, 435/970, 435/975, 436/518, 436/531, 436/807, 436/810, 422/56, 422/58, 422/61, 422/73, 422/101, 422/102
• US Class Current: 435/4
• CPC Class Codes: B01F 21/00 Dissolving separating by dissolving B01D; dissolving to effect cooling F25D5/00
• 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 23/40 Mixing liquids with liquids; Emulsifying
• CPC Class Codes: B01F 23/56 by introducing solids in liquids, e.g. dispersing or dissolving
• CPC Class Codes: B01F 31/00 Mixers with shaking, oscillating, or vibrating mechanisms
• CPC Class Codes: B01F 31/31 using receptacles with deformable parts, e.g. membranes, to which a motion is imparted
• CPC Class Codes: B01F 33/30 Micromixers
• CPC Class Codes: B01F 35/7172 using capillary forces
• CPC Class Codes: B01L 2300/0654 Lenses; Optical fibres
• CPC Class Codes: B01L 2300/069 Absorbents; Gels to retain a fluid
• CPC Class Codes: B01L 2300/0825 Test strips
• CPC Class Codes: B01L 2300/0864 comprising only one inlet and multiple receiving wells, e.g. for separation, splitting
• CPC Class Codes: B01L 2300/087 Multiple sequential chambers
• CPC Class Codes: B01L 2300/0887 Laminated structure
• CPC Class Codes: B01L 2300/1827 using resistive heater
• CPC Class Codes: B01L 2300/1861 using radiation
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 2400/0633 with moving parts
• CPC Class Codes: B01L 2400/0655 pinch valves
• CPC Class Codes: B01L 2400/0694 vents used to stop and induce flow, backpressure valves
• CPC Class Codes: B01L 3/5023 : with a sample being transported to, and subsequently stored in an absorbent for analysis
• 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 3/502715 : characterised by interfacing components, e.g. fluidic, electrical, optical or mechanical interfaces
• CPC Class Codes: B01L 3/50273 : characterised by the means or forces applied to move the fluids micropumps F04B19/006, of the membrane type F04B43/043
• CPC Class Codes: B01L 3/502738 : characterised by integrated valves microvalves F16K99/0001
• CPC Class Codes: G01N 2021/0346 : Capillary cells; Microcells
• CPC Class Codes: G01N 2035/00435 : Refrigerated reagent storage
• CPC Class Codes: G01N 21/51 : inside a container, e.g. in an ampoule G01N21/53 takes precedence
• CPC Class Codes: G01N 21/648 : using evanescent coupling or surface plasmon coupling for the excitation of fluorescence
• CPC Class Codes: G01N 21/78 : producing a change of colour
• CPC Class Codes: G01N 2201/0668 : Multiple paths; optimisable path length
• CPC Class Codes: G01N 33/4905 : Determining clotting time of blood by chemical methods G01N33/86, C12Q1/54
• CPC Class Codes: G01N 33/525 : Multi-layer analytical elements
• CPC Class Codes: G01N 35/0098 : involving analyte bound to insoluble magnetic carrier, e.g. using magnetic separation magnetic particles used in immunoassays G01N33/54326; magnetic separation in general B03C
• CPC Class Codes: Y10S 435/805 : Test papers
• CPC Class Codes: Y10S 435/81 : Packaged device or kit
• CPC Class Codes: Y10S 435/969 : Multiple layering of reactants
• CPC Class Codes: Y10S 435/97 : Test strip or test slide
• CPC Class Codes: Y10S 435/975 : Kit
• CPC Class Codes: Y10S 436/807 : Apparatus included in process claim, e.g. physical support structures
• CPC Class Codes: Y10S 436/81 : Tube, bottle, or dipstick

Abstract

An element and method for easily performing liquid assays are disclosed. The element uses capillary action to draw a predetermined volume of a liquid sample into a reaction chamber charged with reagent, where reaction between the liquid sample and the reagent is monitored.

Claims

1. An apparatus for performing an assay of a liquid sample comprising a reaction element, said reaction element comprising therein a channel structure defining a sample well and a reaction chamber in fluid communication with each other, said channel structure having a geometry causing a liquid sample placed in said sample well to be drawn into and fill said reaction chamber via capillary action, wherein after said reaction chamber is filled said liquid sample remains stationary in said reaction chamber, wherein said apparatus further comprises a means for monitoring a reaction in the reaction chamber, a means for detecting scattered or reflected light emitted from said reaction chamber, a permanent magnet and an electromagnet, wherein said permanent magnet and said electromagnet are in close enough proximity to said reaction element that said permanent magnet and said electromagnet exert their magnetic fields on said reaction element, with said permanent magnet being situated between said electromagnet and said element.

2. The apparatus of claim 1, said reaction element comprising a means for channelling light from an outside source to said reaction volume.

3. The apparatus of claim 1, said reaction element comprising a means for detecting light emitted from said reaction volume.

4. The apparatus of claim 1, said reaction element comprising:

a base comprising a major surface, an overlay on said base, and a cover situated on said overlay, opposite said base;

said overlay comprising therein a channel structure defining a sample well and a reaction chamber in communication with said sample well;

said cover comprising therein a means for adding a sample to be analyzed to said sample well;

a means for channelling light from an outside source to the reaction chamber; and

a means for detecting light emitted from said reaction chamber.

5. The apparatus of claim 4, said reaction element comprising a vent, and a conduit in communication with both the said sample well and said reaction chamber.

6. The apparatus of claim 1, said reaction element comprising a liquid absorbing matrix for withdrawing fluid from said reaction volume.

7. The apparatus of claim 1, wherein said means for monitoring a reaction in said reaction volume employs light and wherein at least some of the external surfaces of the reaction slide not used for transmission of light to the reaction volume or for detection of light emitted from said reaction volume are opaque to light.

8. The apparatus of claim 2, wherein said means for channelling light from an outside source to said reaction volume comprises an optical fiber assembly.

9. The apparatus of claim 4, said reaction element comprising a cover having a length which is less than length of said overlay and less than length of said base, said element comprising an end cover coplanar with said cover and spaced therefrom.

10. The apparatus of claim 8, wherein the distal end of the said overlay is open so that said reaction space vents longitudinally between said cover and said base.

11. The apparatus of claim 10, said reaction element comprising a liquid absorbing matrix fixed to said base and overhanging the said distal end of said cover.

12. The apparatus of claim 4, wherein the distal end of said overlay is open so that said reaction space vents longitudinally between said cover and said base;

said overlay being provided with a first conduit communicating said sample well with said reaction volume, and a second conduit extending backward to a point beyond the sample well wherein end portion of said second conduit is a means for determining that proper filling of said reaction volume with a fluid has been achieved.

13. The apparatus of claim 4, wherein said cover comprises a major planar segment having lateral sides bent downwardly to form walls and then laterally to form tabs, said tabs being bound to said base.

14. The apparatus of claim 1, wherein the internal surfaces of said element have been treated to increase their hydrophilicity.

15. The apparatus of claim 4, wherein said spacer has a thickness of from 0.001 to 0.02 inches.

16. The apparatus of claim 12, wherein said spacer has a thickness of from 0.002 to 0.008 inches.