DNA microwell device and method

• US 5,795,748 A
• Filed: 09/26/1996
• Issued: 08/18/1998
• Est. Priority Date: 09/26/1996
• Status: Expired due to Term

• Current Assignee: Becton, Dickinson & Co
• Original Assignee: Becton, Dickinson & Co
• Inventors: Cottingham, Hugh V.
• Primary Examiner(s): Horlick, Kenneth R.
• Assistant Examiner(s): Tung, Joyce
• Application Number:
  US08/721,372
• Time in Patent Office: 691 Days
• Field of Search: 422/82.05, 422/82.07, 422/82.09, 435/91.2, 435/91.1
• US Class Current: 435/91.2
• CPC Class Codes: B01L 3/5085 for multiple samples, e.g. microtitration plates
• CPC Class Codes: G01N 2021/0346 Capillary cells; Microcells
• CPC Class Codes: G01N 21/03 Cuvette constructions

Abstract

An apparatus for carrying out a homogeneous nucleic acid amplification and nucleic acid assay on a liquid biological sample comprises a sample well and an optical window element which is received in the sample well. Opposed, spaced-apart surfaces of the optical window element and sample well define a capillary chamber into which a liquid biological sample is drawn by capillary force. By spreading the liquid biological sample into a thin film within the capillary chamber, head space is eliminated, heat transfer to the sample is maximized, and a large optical target is achieved to facilitate the detection step of the assay. The disclosed apparatus is particularly suited for use with homogeneous nucleic acid amplification and fluorescence polarization assays, but can also be used in connection with other types of biological and chemical processes.

Claims

1. An apparatus for carrying out a biological or chemical reaction on a liquid sample, comprising:

a plurality of connected sample wells for receiving a liquid sample, each of said sample wells having an interior portion defined by a substantially flat, upwardly facing bottom wall surface and upstanding side wall surfaces;

an optical window element receivable in each of said sample wells, said optical window element having a circumferential edge and a substantially flat, downwardly facing bottom surface which is maintained in opposed, spaced-apart relationship with the bottom wall surface of each of said sample wells to define a capillary chamber therebetween;

an opening between the circumferential edge of said optical window element and a confronting interior side wall surface of each of said sample wells for allowing a liquid sample to be introduced into said capillary chamber and to be drawn into said chamber by capillary action; and

a closure device for sealing said opening after a liquid sample has been introduced into said capillary chamber.

2. An apparatus as claimed in claim 1, wherein said optical window element is maintained in said opposed, spaced-apart relationship with the bottom wall surface of said sample well by at least one spacer carried by an interior wall surface of said sample well.

3. An apparatus as claimed in claim 2, wherein said spacer is integral with said sample well.

4. An apparatus as claimed in claim 2, wherein said spacer includes an engagement portion for engaging said optical window element.

5. An apparatus as claimed in claim 2, wherein said sample well and said optical window element are both substantially cylindrical in shape, and wherein said spacer comprises one of a plurality of spacers disposed around the circumference of the interior portion of said sample well.

6. An apparatus as claimed in claim 1, wherein said optical window element and the interior portion of said sample well have substantially the same shape when viewed from above.

7. An apparatus as claimed in claim 6, wherein said optical window element and the interior portion of said sample well are both substantially circular in shape when viewed from above, and wherein said gap is substantially annular.

8. An apparatus as claimed in claim 1, wherein said closure device is receivable by said sample well in at least partially overlying relationship with said optical window element to seal said opening.

9. An apparatus as claimed in claim 8, wherein said sample well, said optical window element and said closure device are all substantially circular in shape when viewed from above, said closure device overlying said optical window element and having a central aperture for exposing a portion of said optical window element.

10. An apparatus as claimed in claim 1, further comprising a reagent affixed within said capillary chamber for reacting with a liquid sample introduced into said capillary chamber.

11. An apparatus for carrying out a homogeneous nucleic acid amplification and nucleic acid assay on a liquid biological sample, comprising:

a sample well for receiving a liquid biological sample, said sample well having an interior portion defined by a substantially flat, upwardly facing bottom wall surface and upstanding side wall surfaces;

an optical window element receivable in said sample well, said optical window element having a circumferential edge and a substantially flat, downwardly facing bottom surface which is maintained in opposed, spaced-apart relationship with the bottom wall surface of said sample well to define a capillary chamber therebetween;

an opening between the circumferential edge of said optical window element and a confronting interior side wall surface of said sample well for allowing a liquid sample to be introduced into said capillary chamber and to be drawn into said capillary chamber by capillary action;

a closure device receivable in said opening for sealing said opening after a liquid biological sample has been introduced into said capillary chamber; and

a dried nucleic acid amplification reagent for amplifying a target nucleic acid sequence in said liquid biological sample and a dried homogeneous nucleic acid assay reagent for providing an optically detectable indication of the presence of amplified target nucleic acid sequences in said liquid biological sample, said amplification and assay reagents being adhered to the interior of said capillary chamber for reacting with said liquid biological sample.

12. An apparatus as claimed in claim 11, wherein said dried nucleic acid amplification reagent and said dried nucleic acid assay reagent are provided in the form of a single spot adhered to an internal surface of said capillary chamber.

13. An apparatus as claimed in claim 11, wherein said dried nucleic acid assay reagent comprises a fluorescence polarization assay reagent, and wherein said optical window element is made of a material that does not interfere with the transmission of polarized light.

14. An apparatus as claimed in claim 13, wherein said material is selected from the group consisting of cellulose acetate butyrate, triacetate cellulose or glass.

15. An apparatus as claimed in claim 11, wherein said sample well is substantially cylindrical in shape and said optical window element is substantially in the form of a circular disk coaxially receivable within said sample well, and wherein said opening comprises an annular gap between the outer periphery of said window element and confronting interior wall surfaces of said sample well.

16. An apparatus as claimed in claim 15, wherein said closure device comprises an annular seal for sealing said annular gap, said annular seal being frictionally receivable within said sample well and having a central aperture for exposing a corresponding central portion of said window element.

17. An apparatus as claimed in claim 11, further comprising at least one spacer disposed in said sample well for maintaining the bottom surface of said window element in said opposed, spaced-apart relationship with the bottom wall surface of said sample well.

18. An apparatus as claimed in claim 11, wherein said sample well comprises one of a plurality of connected sample wells which are substantially identical to each other, each of said sample wells being provided with one of said window elements, one of said openings, one of said dried nucleic acid amplification reagents, and one of said dried nucleic acid assay reagents.

19. A method for carrying out an integrated nucleic acid amplification and homogeneous nucleic acid fluorescence polarization assay on a liquid biological sample, comprising the steps of:

providing a sample well having a substantially flat, upwardly facing, bottom interior surface;

inserting into said sample well an optical window element having a circumferential edge and a substantially flat, downward facing bottom surface;

maintaining the bottom surface of said optical window element in opposed, spaced-apart relationship with the bottom interior surface of said sample well to define a capillary chamber therebetween;

introducing a liquid biological sample into said capillary chamber through an opening between the circumferential edge of said optical window element and a confronting interior side wall surface of said sample well;

bringing said liquid biological sample into contact with a dried nucleic acid amplification reagent and a dried homogeneous nucleic acid fluorescence polarization assay reagent in said capillary chamber;

sealing said opening;

incubating said sample well to allow said liquid biological sample to react with said nucleic acid amplification reagent and said nucleic acid fluorescence polarization assay reagent; and

detecting fluorescence polarization in said liquid biological sample through said optical window element.

20. A method as claimed in claim 19, wherein said optical window element is made of a material that does not interfere with the transmission of polarized light, and wherein the step of detecting fluorescence polarization in said liquid biological sample comprises directing polarized light through said optical window element.

21. A method as claimed in claim 19, wherein said optical window element is made of a light-polarizing material, and wherein the step of detecting fluorescence polarization in said liquid biological sample comprises directing unpolarized light through said optical window element.