Methods of transporting fluids within an analytical rotor

• US 5,693,233 A
• Filed: 12/04/1995
• Issued: 12/02/1997
• Est. Priority Date: 04/02/1992
• Status: Expired due to Term

• Current Assignee: Abaxis Incorporated (Zoetis Incorporated)
• Original Assignee: Abaxis Incorporated (Zoetis Incorporated)
• Inventors: Schembri, Carol T.
• Primary Examiner(s): KIM, SUN U
• Application Number:
  US08/566,982
• Time in Patent Office: 729 Days
• Field of Search: 210/782, 210/787, 210/360.1, 210/380.1, 210/377, 210/378, 210/512.1, 422/72, 422/100, 422/102, 422/104, 436/45, 356/246, 494/16, 494/17, 494/37
• US Class Current: 210/787
• CPC Class Codes: B01L 2200/16 Reagents, handling or storing thereof
• CPC Class Codes: B01L 2300/0803 Disc shape
• CPC Class Codes: B01L 2300/0864 comprising only one inlet and multiple receiving wells, e.g. for separation, splitting
• 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 2400/0409 centrifugal forces
• CPC Class Codes: B01L 2400/0688 surface tension valves, capillary stop, capillary break
• 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: G01N 21/07 Centrifugal type cuvettes G01N21/09 takes precedence
• CPC Class Codes: G01N 21/78 producing a change of colour
• CPC Class Codes: G01N 33/491 by separating the blood components G01N15/05 takes precedence
• CPC Class Codes: Y10T 436/111666 Utilizing a centrifuge or compartmented rotor

Abstract

The present invention provides an analytical rotor which holds a fluid in a chamber, typically to allow mixing with a reagent, and transfers the fluid to a receiving chamber in the rotor. The rotor comprises a holding chamber having an single exit duct and a receiving chamber connected to the holding chamber through the exit duct. The exit duct prevents flow at a first rotational speed and allows flow at a second, higher rotational speed. The exit duct may include a capillary passage in which capillary forces prevent flow until the rotational speed is increased. Alternatively, the exit duct may include a siphon.

Claims

1. A method for delivering, in a centrifugal rotor, a fluid from a holding chamber to a receiving chamber positioned radially outward from the holding chamber, the holding chamber having an exit duct connected through a capillary passage to said receiving chamber, the method comprising the steps of:

spinning the rotor at a first rotational speed, thereby transferring said fluid from a loading chamber positioned radially inward from said holding chamber through an entry channel into said holding chamber; and

spinning the rotor at a second higher rotational speed, thereby transferring the fluid from the holding chamber to the receiving chamber through said exit duct and capillary passage, wherein said capillary passage has a cross sectional area less than the cross sectional area of the entry channel such that flow of fluid from the holding chamber to the receiving chamber is prevented at the first rotational speed and allowed at said second higher rotational speed.

2. The method of claim 1, wherein the holding chamber is a mixing chamber.

3. The method of claim 2, wherein the mixing chamber comprises a marker compound.

4. A method for contacting, in a centrifugal rotor, a fluid with a reagent, the method comprising the steps of:

spinning the rotor at a first rotational speed, thereby introducing said fluid from a loading chamber in said rotor through an entry channel into a holding chamber positioned in said rotor radially outward from said loading chamber, said holding chamber having an exit duct and comprising a reagent coated on a solid surface therein where said fluid combines with said reagent thereby forming a mixture and

spinning the rotor at a second higher rotational speed, thereby transferring the fluid from the holding chamber to a receiving chamber positioned radially outward from the holding chamber through the exit duct and a capillary passage wherein said capillary passage has a cross sectional area such that flow of fluid from the holding chamber to the receiving chamber is prevented at the first rotational speed and allowed at said second higher rotational speed.

5. The method of claim 4 further comprising the step of changing the direction of rotation after the fluid is introduced into the holding chamber thereby mixing the fluid and the reagent.

6. The method of claim 4, wherein the fluid is a biological fluid.

7. The method of claim 4, wherein the fluid is a diluent.

8. The method of claim 4, wherein said solid surface is a bead disposed within said holding chamber.

9. A method of delivering, in a centrifugal rotor, a fluid to a separation chamber having a cell trap, the method comprising:

spinning the rotor to effect a radial outward flow of the fluid from a loading chamber through a passage into a holding chamber having an exit duct;

stopping the rotation of the rotor, thereby priming a siphon connecting the exit duct to the separation chamber; and

spinning the rotor, thereby delivering the fluid to the separation chamber through the exit duct and the siphon.

10. A method of delivering, in a centrifugal rotor, a fluid to a metering chamber, the method comprising:

spinning the rotor to effect a radial outward flow of the fluid from a loading chamber through a passage into a holding chamber having an exit duct;

stopping the rotation of the rotor, thereby priming a siphon connecting the exit duct to the metering chamber; and

spinning the rotor, thereby delivering the fluid to the metering chamber through the exit duct and the siphon.