AU478144B2 - Rotor having sample holding means - Google Patents

Description

58,021n3 improved photometric analyzer which is amenable to serological

testing requiring repeated washing or dilution of particulates.

It was made in the course of, or under, a contract with the

U. S. Atomic Energy Commission.

Many serological tests involve phenomena shown by

liquid-suspended particles having specific antigens or anti-

bodies affixed thereto. In basic examples, these tests

involve blood cells, bacterial cells, and the like. In more

recently developed tests such as those described in copending

application Ser. No. 223,018 of common assignee, the sero-

logical factors are attached to chemically stable carrier

particles such as synthetic resin beads. Attachment of

additional antibodies or antigens to these carrier particles

may result in an agglutination reaction which may be observed

directly. In other cases, reacted carrier particles may be

centrifugally separated from the suspending liquid by

sedimentation with or without a liquid density gradient, and

the serological factor secondarily attached thereto identified

by a change in particle sedimentation rate or banding density.

Most serological tests of the foregoing type require

centrifugal sedimentation of the carrier particles and repeated

washing steps. The actual means by which the various reactions

are performed, the specific reagents used, the reaction times,

and the sequence of the washing and reaction steps vary

considerably for different tests. The unique parallel mode

of operation of fast photometric analyzers of the rotary

cuvette type, wherein.samples and reagents are mixed in a

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8,021 n3 centrifugal field and absorbance or fluorescent measurements

are made on a multiplicity of reaction mixtures during

rotation, makes them of interest for use in the automation

of immunological analyses. This necessitates the development

of a cuvette rotor which permits extensive washing of red

cells or other carrier particles, reaction with one or more

reagents (with interspersed washes, if necessary), and

determination of the degree of agglutination, extent of

hemolysis, and presence or absence of fluorescence-labelled

antibody or radioactivity in either the supernatant or

sediment.

It is, accordingly, a general object of the invention to

provide a fast photometric analyzer of the rotary cuvette

type which is suitable for immunological analyses requiring

repeated washings of carrier particles.

Another, more particular object of the invention is to

provide a fast photometric analyzer of the rotary cuvette

type which is capable of performing sample and reagent

division, mixing, sedimentation, washing, transfer, and light

absorbancy functions.

Other objects of the invention will be apparent from an

examination of the following description of a preferred

embodiment and the appended claims.

Summary of the Invention

In accordance with the invention, a photometric analyzer

of the multistation, rotary cuvette type is provided which is

4 47 8.144

8.021 n3 mixing, capable of performing sample and reagent division, func- sedimentation, washing, transfer, and light absorbancy

tions. Two sets of cavities are formed in concentric

arrays within a disk adapted to rotate about its central

axis. The radially outer set of cavities constitutes a

rotary cuvette system where photometric measurements are

made. Cavities in the radially inner set of cavities,

herein designated loading cavities, communicate, on a one-

to-one basis, with respective cavities in the radially

outer set. A barrier between each loading cavity and a

corresponding cuvette allows centrifugal transfer of fluids

upon rotation of the disk while preventing such transfer

or return of fluids under static conditions. A radially

extending passageway positioned angularly to one side of

the barrier results in improved mixing in the cuvettes.

A drainline extends radially inward from a point adjacent

the radial extremity of each cuvette to a vacuum source for

removing overlaying liquid within the cuvettes following

particle sedimentation therein. A central receiving and

distribution chamber bordered by segmentation serrations

is in fluid communication with each loading cavity to

facilitate loading of those cavities under static or dynamic

conditions. Use of the subject analyzer permits the making

of multiple serological analyses requiring repeated

washing or dilution and sedimentation steps in a rapid

manner. 47 8.144

58,0 21 n3 Brief Description of the Drawings

Fig. 1 is a vertical sectional view, highly schematic,

of a multistation, rotary type photometric analyzer made in

accordance with the invention.

Fig. 2 is a top plan view of a rotor assembly used in

the photometric analyzer of Fig. 1.

Figs. 3,4,5,6,7, and 8 illustrate the operation of the

rotor assembly of Fig. 2 in performing reaction, sedimentation,

washing, and fluid transfer functions.

Description of the Preferred Embodiment

Fig. 1 illustrates, in a vertical sectional view, a

photometric analyzer made in accordance with the invention.

A pancake-shaped rotor assembly 1 includes a flanged steel

rotor body 2, transparent glass or plastic plates 3 and 4,

a polytetrafluorethylene or other plastic disk 5 defining

loading cavities and cuvettes, and a bolted flange ring 6

for holding plates 3 and 4 and disk 5 within rotor body 2.

Plates 3 and 4 and disk 5 are sandwiched together between

rotor body 2 and flange ring 6 to form loading cavities

7 and cuvettes 8 which are disposed in concentric annular

arrays at respectively increasing rotor radii. Drainlines

9 extend from a point adjacent the radial extremity of each

cuvette 8 to a central vacuum plenum 10 which passes through

drive and support shaft 11 to a vacuum source (not shown).

A sloping barrier 12 separates each loading cavity 7 from a

corresponding cuvette 8 under static conditions while

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2 1 n3 permitting centrifugal transfer of liquids from the loading

cavities to the cuvettes. Recesses 13 in plate 4 are

positioned directly above each barrier 12 to permit liquid

to flow over the barrier into cuvettes 8 during rotation

of the rotor assembly. The slope, spacing, and orientation

of loading cavities 7, cuvettes 8, and drainlines 9 are

further illustrated in the plan view of Fig. 2, which is

described below.

Cuvettes 8 are designed to permit simultaneous photometric

analyses of a multiplicity of discrete samples. To facilitate

such analyses, a multiplicity of spaced-apart holes 14,

axially aligned with and equal in number to cuvettes 8,

are provided in rotor body 2. Light passing through holes

14 continues through transparent plate 3, cuvettes 8, and

transparent plate 4 to a photodetector as indicated

schematically by a broken line in Fig. 1. A system of

photometric light source, photodetecting means, and other

ancillary electronic components suitable for use with the

above rotor assembly is described in copending application

of common applicant and assignee Ser. No. 784,739. That

system will not be described here inasmuch as the invention

in this case is an improvement restricted to the design of

the rotor assembly and its method of use only and does not

encompass the associated components described in the copending

application.

Referring now to Fig. 2 where a plan view of disk 5 is

shown, only two of sixteen pairs of loading cavities and

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8,0 21 n3 cuvettes are shown for purposes of drawing simplification.

A central liquid distribution chamber 15 is provided with

a serrated periphery in the form of stream segmenting blades

16 for dividing liquid inserted during rotation into sub-

stantially equal volumes and for distributing the volumes

thus divided to respective loading cavities and cuvettes. As

shown, radially extending passageways 17 are positioned

angularly to one side of each barrier 12 to permit passage of

liquid along the corresponding side of mixing cavities 7 and

cuvettes 8, thereby enhancing the mixing action in cuvettes 8

through a vortex flow effect illustrated in Fig. 5. The

operation of loading cavities 7, cuvettes 8, barrier 12,

passageway 17, and drainlines 9 may best be understood

by referring to Figs. 3 through 8 where the stepwise operation

of the subject photometric analyzer is illustrated.

An initial loading of blood samples or other particulate

suspension 18 is first made under static conditions as

illustrated in Fig. 3. Access to loading cavities 8 may be

made through opening 19 in plate 4 (see Fig. 1) by any suitable

loading apparatus such as a hypodermic syringe. Alternatively, a small transfer disk (not shown) may be used to perform the

sample loading operation. Fig. 4 illustrates the centrifugal transfer of sample 18 to the radial extremity of a corresponding

cuvette 8. Transfer of the sample to cuvette 8 is accomplished

by the sample passing over the sloping barrier 12 through

the clearances provided by recessed 13 in plate 4. As shown, the samples are spread in a thin layer on the radially outer

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8,0 21 n3 action. wall 20 of each cuvette 8 by the centrifugal

being directed against Fig. 5 shows a diluent stream

After striking blades 16, the segmentation blades 16. each loading cavity divided diluent flows along one side of

and thence inco cuvecte ,:h-ere it 7, :hrough passagaeay 17,

Coriolis forces cause the diluent mixes with sample 18.

cavity 7 and cuvette stream to pass along one side of loading

8 in the manner illustrated. The diluent stream may be a

or a reactant washing liquid such as physiological saline

upon the particular such as a solution of antibodies depending

analysis. analysis being performed and the stage of the or wiahi:Lg Rapid and thorough mixing of sample and reactant has long liquids, as achieved by the subject invention, for accurate been recognized as desirable and necessary

Followin~ addition of the diluent ii.trated analysis.

in Fig. 5, particulates in the mixture are centrifugally

sedimented against the outer wall 20 of cuvette 3 as shown

in Fig. 6, leaving overlaying liquid 21. The overlaying

through drainline liquid 21 is then removed by applying vacuum

9 as shown in Fig. 7. Alternatively, the aperture 19 in

applied plate 4 may be closed and air or other gas pressure Repeated to the central chamber through a suitable seal.

as shown washing and/or reaction steps may then be initiated

in Fig. 8 by again adding a suitable diluent during rotation,

After resuspending the particulates, and resedimenting.

washing, various reagents may be added and removed sequentially.

the rate at Agglomeration may be measured by determining

9 47 8.144

58.021 3 which resuspended particles are sedimented using photometric

techniques in the usual manner. By using a thin pencil of

light such as obtained from a slit light source, the

sedimentation of particles past a fixed radial position may

be observed by observing the output of the photodetector.

For measurement of sedimentation rate, two slit light sources

spaced at different radial positions may be employed and the

time required for a sedimenting boundary to pass from one

radius to another measured.

Cuvette rotors made in accordance with the invention may

be used for the purpose of sedimentation to clarify liquid

containing a suspended particulate prior to determining

absorbancy of the supernatant liquid remaining after

sedimentation. Particulate phenomena, including agglomeration,

lysis, fluorescence, and radioactivity, can be observed

continuously by appropriate detecting means. Supernatant

liquid phenomena, including optical density, light scattering,

fluorescence, radioactivity, and light absorbancy, can also

be observed.

The above description of one embodiment of the invention

is offered for illustrative purposes and should not be

interpreted in a limiting sense. For example, drainlines

9 may be reoriented to discharge into a vacuum chamber

about the periphery of disk 5 or repositioned to communicate

with the bottoms of respective cuvettes 8 so that washed

cells or other particulates may be recovered from the

cuvettes with the rotor assembly at rest for tests in other

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8.0 21 n3 instruments. Such repositioning would require drainlines cuvette 9 to be inclined upward toward plate 4 to avoid or drainage due to gravity alone while permitting vacuum

pressure forced recovery. Also, a wide variety and

be performed sequence of washing and reacting steps may the particular using the subject analyzer depending upon be analysis. It is intended, rather, that the invention hereto. limited only by the scope of the claims appended

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Claims (1)

1. 58.021 M The claims defining the invention are as follows. 1. In a photometric analyzer including a rotor assembly

   defining a circular array of sample analysis cuvettes adapted

   to repeatedly pass between a light source and a photodetector

   for photometric analysis of the cuvette contents, the improved

   rotor assembly which defines:

   a circular array of loading cavities disposed

   concentrically within said circular array of sample analysis

   cuvettes, each of said loading cuvettes being in radial

   alignment with a corresponding cuvette in said circular array

   of cuvettes;

   sloped barriers interposed between said loading

   cavities and cuvettes to prevent transfer of liquid there-

   between under static conditions while permitting centrifugal

   transfer of liquids from said loading cavities to corresponding

   cuvettes, said barriers each defining a radially oriented

   mixing passageway which is positioned angularly to one side

   of said barrier and extends through said barrier; and

   a drain passageway communicating with each of

   said cuvettes at a point adjacent the radial extremity of

   said cuvette, said drain passageway leading from said cuvette

   to an external vacuum source.

   2. The improved rotor assembly of claim 1 wherein

   said drain passageway extends radially inward at least as

   far as said sloped barriers.

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   8,021 n3

   3. The improved rotor assembly of claim 1 wherein each

   of said radially oriented mixing passageways is radially

   aligned with one side wall of a corresponding loading cavity

   and cuvette.

   4. The improved rotor assembly of claim 1 wherein a

   central loading and distribution chamber is provided adjoining

   the radially inner edge of said loading cavities, and wherein

   said chamber has a serrated periphery for causing liquid

   fed therein to be substantially equally distributed to said

   loading cavities when said rotor assembly is rotating.

   Dated this l8th day of June 1973.

   UNITED STATES ATOMIC SNE.-Y CO 'ISSION

   CCIE, ITlUi..:; CARTER PATENT ATTORNEYS 343 LITTLE COLLINS STREET

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   2 1 M7

   IG. 2

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