Cartridge for containing a specimen sample for optical analysis

• US 20020109838A1
• Filed: 02/12/2002
• Published: 08/15/2002
• Est. Priority Date: 02/12/2001
• Status: Active Grant

• Current Assignee: Menarini Silicon Biosystems S.P.A
• Original Assignee: Immunivest Corporation
• Inventors: Columbus, Richard L.
• Granted Patent: US 6,861,259 B2
• Time in Patent Office: Days
• US Class Current: 356/246
• CPC Class Codes: B01L 3/508 rigid containers not provided for above
• CPC Class Codes: G01N 2021/0346 Capillary cells; Microcells
• CPC Class Codes: G01N 21/03 Cuvette constructions
• CPC Class Codes: G01N 21/11 Filling or emptying of cuvettes
• 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: G02B 21/34 Microscope slides, e.g. mounting specimens on microscope slides

Abstract

A cartridge for holding a test specimen with an extremely small volume. The cartridge has a test chamber and a vestibule through which the test fluids are inserted into the test chamber. The cartridge has a stopper having a pair of seals, the first of which seals the test chamber inlet between the vestibule and the test chamber, and the second of which seals the mouth of the vestibule so that when the stopper is in place, the test chamber is closed to the admission of air or other contaminants and the vestibule is similarly closed against escape of the overflow from the test chamber.

Claims

1. A method sealing a chamber to preclude air entrapment in a test liquid, comprising:

(a) providing an analytic chamber having a test chamber and an overflow reservoir;

(b) filling the analytic chamber to a fill line such that the test chamber is completely filled with liquid;

(c) seating a primary seal within the analytic chamber to form a seal interface that lies between the test chamber and the overflow reservoir within the liquid volume in the analytic chamber;

(d) retaining any evacuated liquid displaced upon seating the primary seal into the overflow reservoir; and

(e) sealing the overflow reservoir with a second seal to preclude voiding of the overflow reservoir and rupturing of the primary seal.

2. A method according to claim 1 in which said step of filling the chamber with liquid includes

one step of introducing a test liquid into the chamber having a volume sufficient to fill the test chamber to a level below said fill line, and

a second step of introducing a buffer solution having a density different from the density of the test liquid to the chamber, the combined volume of said test liquid and said buffer being sufficient to bring the surface of said combined liquids to said fill line, said test liquid and buffer solution providing a liquid interface within the test chamber having buffer solution on one side and test liquid at the other side,

said seating step displacing buffer solution from the one side of said liquid interface into said overflow reservoir, whereby all of said test liquid is retained in the test chamber, and air is excluded from the test chamber.

3. A method according to claim 2 in which said overflow reservoir is above said test chamber and said buffer solution has a density not more than the density of the test liquid, including the steps of

connecting the overflow reservoir to the test chamber by an inlet adjacent to said fill line and spaced above the liquid interface, and

seating said primary seal in the inlet.

4. A method according to claim 1, including the steps of

providing a stopper having a primary sealing element adjacent its distal end and a second sealing element adjacent its proximal end,

inserting the stopper into and through the overflow reservoir to seat the primary sealing element between the test chamber and the reservoir, the distal end of said stopper displacing liquid from the test chamber into the reservoir, and thereafter

seating the second sealing element to seal the overflow reservoir.

5. A seal system for sealing a test chamber to preclude air entrapment in liquid inserted into the chamber, said system comprising:

(a) a test chamber having a longitudinal axis adapted to be disposed vertically as liquid is inserted therein, and having a vestibule above said test chamber, an inlet between said test chamber and said vestibule, and a fill line located adjacent said inlet, said fill line determined by the surface of liquid inserted into said test chamber;

(b) a stopper having a first seal adapted to sealingly seat in the inlet and close the same, said stopper having a distal end adapted to enter the inlet of the test chamber below the fill line before the first seal closes said inlet, said distal end having a thickness sufficient to displace upwardly liquid through said inlet and position the surface of the liquid in said vestibule prior to said first seal closing said inlet, said first seal, upon being seated in the inlet, precluding air entrapment within the test chamber;

(c) said vestibule having a volume to form an overflow reservoir for receiving a volume of liquid that may be displaced upon seating the primary seal; and

(d) a second seal remote form the first seal in said vestibule, said first and second seals defining therebetween the overflow reservoir, said second seal precluding migration of any overflow liquid past the second seal out of the system.

6. A system according to claim 5 wherein said test chamber is separated from said vestibule by the top wall of the test chamber and wherein further said inlet is positioned within said top wall.

7. A system according to claim 5 in which said stopper has a stem adapted to extend through said vestibule, with a distal end adapted to pass through said inlet of said test chamber and a proximal end adapted to be positioned above said vestibule, said first seal being positioned on said stem adjacent the distal end, and the second seal being positioned on said stem adjacent the proximal end.

8. A system according to claim 7 wherein said inlet comprises a tapered passage terminating in a cylindrical channel providing a seat for said first seal, and an upwardly open mouth providing a seat for the second seal, said first seal comprising a probe at the distal end of said stem adapted to pass through said tapered passage and into said cylindrical channel to seal the inlet, and said second seal comprising a plug adapted to sealingly engage in said open mouth.

9. A system according to claim 8 wherein said cylindrical channel is disposed centrally in the top wall of said test chamber and has an internal diameter substantially smaller than the internal dimensions of the test chamber.

10. A system according to claim 8 wherein the distance between the distal end of the probe and the plug is greater than the distance between the cylindrical channel and the mouth, whereby the probe completes the first seal before the plug effects the second seal.

11. A system according to claim 10 wherein said mouth is a socket, and said plug is a block complementary to said socket.

12. A system according to claim 10 wherein said stem has ribs extending between said probe and said plug.

13. A system according to claim 5 wherein said test chamber has longitudinal side walls of translucent plastic material with no fluorescent additives to enable optical analysis of the liquid inserted in the test chamber.

14. A system according to claim 13 wherein at least one of said longitudinal sidewalls of the test chamber is flat.

16. A cartridge according to claim 15 wherein said test chamber has a volume of at least 315 μ

l and said vestibule has a volume of at least 95 μ

l when the first of said stopper seals is seated in the inlet and the second seal is precluding migration of any overflow liquid past the second seal.

17. A cartridge according to claim 15 wherein said test chamber has a volume in the range of 22 ml to 675 μ

l.

18. A cartridge according to claim 15 wherein said test chamber has a cross-sectional area in the range of 10 to 14 square millimeters and the inlet has a diameter of 2.35 mm.

15. A cartridge containing a test chamber for use in apparatus for performing optical analysis of liquid specimens by optical observation, said apparatus having a receptacle for receiving the cartridge and positioning the test chamber of the cartridge in a field of observation of the apparatus to enable analysis of liquid within the test chamber, the apparatus having at least two magnetic poles positioned on opposite sides of the receptacle to apply a magnetic field to the cartridge, said cartridge comprising:

a body of translucent plastic adapted to be slidably engaged in the receptacle of the apparatus between said magnetic poles to position the test chamber in the magnetic field of said poles, said body having a domed cross section with a flat land area adapted to be positioned in the field of observation of the apparatus,

a test chamber underlying said flat land area and having a longitudinal axis adapted to be disposed vertically when liquid is inserted therein, and having a vestibule above said test chamber, an inlet between said test chamber and said vestibule, and a fill line located adjacent said inlet, said fill line determined by the surface of liquid inserted into said test chamber;

a stopper having a first seal adapted to sealingly seat in the inlet and close the same, said stopper having a distal end adapted to enter the inlet of the test chamber below the fill line before the first seal closes said inlet, said distal end having a thickness sufficient to displace liquid upwardly through said inlet and position the surface of the liquid in said vestibule prior to said first seal closing said inlet, said first seal, upon being seated in the inlet, precluding air entrapment within the test chamber;

said vestibule having a volume to form an overflow reservoir for receiving a volume of liquid that may be displaced upon seating the primary seal; and

a second seal remote form the first seal in said vestibule, said first and second seals defining therebetween the overflow reservoir, said second seal precluding migration of any overflow liquid past the second seal out of the system.