# US 5,346,831 A · Cytorich process system

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- Number: US 5,346,831 A
- Document ID: US5346831A
- Status: Granted
- Kind: A
- Application number: 08/112,001
- Filed: 1993-08-30
- Granted: 1994-09-13
- Earliest claimed: 1992-09-29
- Assignees: Hoffman-La Roche Inc.
- Inventors: Charles L. Carrico, Jr.; William A. Fox; James W. Geyer; Ernest A. Knesel, Jr.
- Web page: https://patentgrep.com/patent/US5346831A

## CPC

- G01N 1/2813: {Producing thin layers of samples on a substrate, e.g. smearing, spinning-on (G01N1/30 takes precedence)}
- G01N 2001/2846: {Cytocentrifuge method}
- Y10T 436/112499: with sample on test slide
- Y10T 436/25: including sample preparation
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A process for producing a monolayer of cytological material on an optically-clear, cationically-charged substrate, includes the steps of separating the cytological material by centrifugation over a density gradient, producing a packed pellet of the cytological material, mixing the pellet of the cytological material, withdrawing an aliquot of a predetermined volume of the material from the mixed pellet of the cytological material, depositing the aliquot and a predetermined volume of water into a sedimentation vessel, which is removably secured to the substrate, allowing the cytological material to settle onto the substrate under the force of gravity, and after settlement of the cytological material, removing the water from the sedimentation vessel.

## Claims

### Claim 1

A method for preparing a monolayer of a cytological material on a cationically-charged substrate, which comprises the steps of:
(a) separating the cytological material by centrifugation over a density gradient;
(b) producing a packed pellet of the cytological material;
(c) mixing the pellet of the cytological material;
(d) withdrawing an aliquot of a predetermined volume from the mixed pellet of the cytological material;
(e) depositing the aliquot in a predetermined volume of water into a sedimentation vessel having a base, which vessel is removable secured to the cationically-charged substrate;
(f) allowing the cytological material to settle onto the substrate under the force of gravity without flow of the aliquot and the water from the base of the sedimentation vessel;
(g) after settlement of the cytological material, removing the water from the sedimentation vessel.

### Claim 2 (depends on 1)

The method of claim 1, wherein the separating comprises centrifuging the cytological material at a force of about 600G over a density gradient comprising 6% hetastarch solution.

### Claim 3 (depends on 1)

The method of claim 1, wherein producing a packet pellet comprises centrifuging the cytological material at a force of about 800G over a density gradient comprising 6% hetastarch solution.

### Claim 4 (depends on 1)

The method of claim 1, wherein withdrawing the aliquot of a predetermined volume comprises withdrawing approximately 150 .mu.L of the mixed pellet.

### Claim 5 (depends on 1)

The method of claim 1, wherein the depositing comprises mixing the aliquot of cytological material with approximately 500 .mu.L of water.

### Claim 6 (depends on 1)

The method of claim 1, wherein the depositing is to the substrate comprising a glass microscope slide.

### Claim 7 (depends on 1)

The method of claim 1 further comprising staining the cytological material within the sedimentation vessel after settlement of the cytological material.

### Claim 8 (depends on 7)

The method of claim 7, wherein the staining comprises applying a Papanicolaou stain.

### Claim 9 (depends on 1)

The method of claim 1, wherein the mixing of the pellet of the cytological material further comprises adding thereto a predetermined volume of water.

### Claim 10 (depends on 9)

The method of claim 9, wherein the predetermined volume of water added during mixing is approximately 50 .mu.L.

### Claim 11 (depends on 1)

The method of claim 1 further comprising detaching the sedimentation vessel from the substrate.