Biological assay cassette and method for making same
First Claim
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1. A centrifugal force responsive fluid metering device for use with biological assay cartridges, comprising:
- a slidable metering member having a pre-determined mass and defining a metering cavity for metering a precise quantity of analyte in a fluid, the metering member being moveable from a first collecting position through a second sealed position to a third dispensing position;
a fluid metering chamber for slidably supporting the metering member and for containing the fluid to be metered, the metering chamber having a sealing surface slidably abutting the metering member so as to define a predetermined gap distance therebetween and having a surface area sufficiently large to completely enclose the metering cavity when the metering member is in the second sealed position and sufficiently small to permit the metering cavity to be filled with the fluid when the metering member is in the first collecting position and to permit the metering cavity to dispense the fluid therefrom when the metering member is in the third dispensing position; and
a sealing material positioned in the gap between the metering member and the sealing surface to substantially prevent fluid communication between the first fluid collecting and third fluid dispensing positions except for the metered quantity of fluid, the sealing material having a preselected shear strength, whereby the metering member slides from the first to third positions only upon application of a first predetermined centrifugal force thereto in a predetermined direction defined by the first, second and third positions. supplemental sealing means for sealing the fluid metering chamber when the metering member is in the third fluid dispensing.
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Abstract
A modular reaction cassette has a fluid metering mechanism and valves for releasing fluid which are actuated by various centripetal acellerations generated in an automated patient analysis instrument having a variable speed rotor. Various geometries and sealant materials are used to select the rotational speed at which the sealant material yields to operate the metering device and release valves.
50 Citations
21 Claims
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1. A centrifugal force responsive fluid metering device for use with biological assay cartridges, comprising:
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a slidable metering member having a pre-determined mass and defining a metering cavity for metering a precise quantity of analyte in a fluid, the metering member being moveable from a first collecting position through a second sealed position to a third dispensing position; a fluid metering chamber for slidably supporting the metering member and for containing the fluid to be metered, the metering chamber having a sealing surface slidably abutting the metering member so as to define a predetermined gap distance therebetween and having a surface area sufficiently large to completely enclose the metering cavity when the metering member is in the second sealed position and sufficiently small to permit the metering cavity to be filled with the fluid when the metering member is in the first collecting position and to permit the metering cavity to dispense the fluid therefrom when the metering member is in the third dispensing position; and a sealing material positioned in the gap between the metering member and the sealing surface to substantially prevent fluid communication between the first fluid collecting and third fluid dispensing positions except for the metered quantity of fluid, the sealing material having a preselected shear strength, whereby the metering member slides from the first to third positions only upon application of a first predetermined centrifugal force thereto in a predetermined direction defined by the first, second and third positions. supplemental sealing means for sealing the fluid metering chamber when the metering member is in the third fluid dispensing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A force responsive fluid metering cassette for performing biological assays and chemical reactions, comprising:
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a metering chamber having means for accepting a fluid to be metered and means for precisely metering a portion of the fluid upon application of a first centrifugal force; a first reaction chamber for containing a first reaction fluid, the reaction chamber being connected to the metering chamber and having means for receiving the metered fluid therefrom and means for releasing the contents of the reaction chamber upon application of a second predetermined centrifugal force greater than the first centrifugal force; and a photometric analysis chamber connected to the first reaction chamber so as to receive the contents of the first reaction chamber therefrom for photometric analysis in a fluid contained in the photometric analysis chamber, the photometric analysis chamber further including accumulation means for concentrating the population density of particles above a fluid interface in the photometric analysis chamber to facilitate the movement of the particles across a fluid meniscus formed at the fluid interface by centrifugal force. - View Dependent Claims (18)
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19. An acceleration responsive fluid metering cassette for performing biological assays and chemical reactions, comprising:
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an enclosed reaction chamber having means for making a photometric determination of the contents therein; a metering chamber within the reaction chamber, the metering chamber having means for accepting a fluid to be metered and means for precisely metering a portion of the fluid into the reaction chamber upon application of a first centrifugal force; a first reaction fluid container in the reaction chamber for containing a first reaction fluid, the reaction fluid container having means for releasing the first reaction fluid upon application of a second predetermined centrifugal force greater than the first centrifugal force. - View Dependent Claims (20)
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21. A centrifugal force-sensitive release valve, comprising:
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a movable member having a predetermined mass and a sealing surface thereon; a fixed member having an aperture therein sized to slidably receive the fixed member so as to form a peripheral gap therebetween in the approximate range of 0.002" to 0.020"; and a sealing material in the peripheral gap having a preselected strength, whereby application of a predetermined force on the moveable member will shear the sealing material and allow the moveable member to move.
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Specification