# US 9,040,255 B2 · Use of diazolidinyl urea for anti-clumping of biological samples

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- Number: US 9,040,255 B2
- Document ID: US9040255B2
- Status: Granted
- Kind: B2
- Application number: 13/243,432
- Filed: 2011-09-23
- Published: 2012-06-28
- Granted: 2015-05-26
- Earliest claimed: 2010-09-23
- Assignees: Biocept, Inc.
- Applicants: Pavel Tsinberg; Stephen D. Mikolajczyk
- Inventors: Pavel Tsinberg; Stephen D. Mikolajczyk
- Web page: https://patentgrep.com/patent/US9040255B2

## CPC

- G01N 33/54393: {Improving reaction conditions or stability, e.g. by coating or irradiation of surface, by reduction of non-specific binding, by promotion of specific binding}
- A61B 5/1405: {Devices for taking blood samples (devices for taking samples of other body liquids A61B10/0045)}
- A61B 5/150343: {Collection vessels for collecting blood samples from the skin surface, e.g. test tubes, cuvettes (sampling from within body cavities A61B5/150015, A61B5/150045)}
- A61B 5/150755: {Blood sample preparation for further analysis, e.g. by separating blood components or by mixing}
- A61B 5/154: {Devices} using pre-evacuated means
- A61B 10/02: Instruments for taking cell samples or for biopsy {(A61B10/0038 and A61B10/0045 take precedence; needle locating or guiding means A61B17/3403; samplers for enzymology or microbiology C12M1/26; sampling or preparing biological specimens G01N33/48)}
- Y10T 436/17: Nitrogen containing
- Y10T 436/171538: Urea or blood urea nitrogen
- Y10T 436/173845: Amine and quaternary ammonium
- Y10T 436/174614: Tertiary amine
- Y10T 436/25: including sample preparation
- Y10T 436/2525: Stabilizing or preserving
- 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)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The present invention provides methods for preventing clumping of cells in microfluidic devices by addition of diazolidinyl urea (DU). DU can be added to samples at the time of collection or can be added to samples post-collection. DU can also be pre-added to sample collection devices.

## Claims

### Claim 1

A method of inhibiting cellular aggregation in a biologically active sample comprising mixing an effective amount of diazolidinyl urea with a sample of viable cells, wherein the effective amount of diazolidinyl urea is in a concentration of about 0.01% to about 3% upon mixing with the sample of viable cells.

### Claim 2 (depends on 1)

The method of claim 1, further comprising mixing an effective amount of diazolidinyl urea in combination with a non-chelating agent based anti-coagulating agent with the sample.

### Claim 3 (depends on 1)

The method of claim 1, further comprising mixing an effective amount of diazolidinyl urea in combination with acid citrate dextrose with the biological sample.

### Claim 4 (depends on 1)

The method of claim 1, wherein the diazolidinyl urea is mixed with the sample before or during a biological sample processing or testing.

### Claim 5 (depends on 1)

The method of claim 1, wherein the diazolidinyl urea is in a solid or liquid form in a container and wherein the biological sample is added to the container.

### Claim 6 (depends on 1)

The method of claim 1, wherein the biological sample is selected from the group consisting of whole blood, blood serum, plasma and bone marrow.

### Claim 7 (depends on 1)

The method of claim 1, wherein upon mixing with the effective amount of diazolidinyl urea the biological sample is suitable for use in a microchannel for cell capturing.

### Claim 8 (depends on 1)

The method of claim 1, wherein the effective amount of diazolidinyl urea in the biological sample provides for improved cell capture in a microchannel as compared to that in the absence of diazolidinyl urea in the biological sample.

### Claim 9

A method of inhibiting cellular aggregation in a biological sample comprising mixing an effective amount of diazolidinyl urea with the sample, wherein cellular aggregation is reduced in the presence of diazolidinyl urea compared to the absence of diazolidinyl urea in the sample, wherein the effective amount of diazolidinyl urea is about 0.01% to about 3% upon mixing with the biological sample, and wherein upon mixing with the effective amount of diazolidinyl urea the biological sample is suitable for use in a microchannel for cell capturing.

### Claim 10 (depends on 1)

The method of claim 1, wherein the effective amount of diazolidinyl urea is about 0.1% to about 2.5% upon mixing with the biological sample.

### Claim 11 (depends on 1)

The method of claim 1, wherein the effective amount of diazolidinyl urea is about 0.2% to about 2% upon mixing with the biological sample.