# US 2025/0146044 A1 · Rinse solution for microbial detection systems

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2025/0146044 A1
- Document ID: US20250146044A1
- Status: Published application
- Kind: A1
- Application number: 18/936,099
- Filed: 2024-11-04
- Published: 2025-05-08
- Earliest claimed: 2023-11-06
- Assignees: Rapid Micro Biosystems, Inc.
- Applicants: Rapid Micro Biosystems, Inc.
- Inventors: Owen GRIFFIN; Juan Pablo RODRIGUEZ SANTANA; Courtney RUSSELL; David JONES
- Web page: https://patentgrep.com/patent/US20250146044A1

## CPC

- C12Q 1/04: Determining presence or kind of microorganism; Use of selective media for testing antibiotics or bacteriocides; Compositions containing a chemical indicator therefor {(C12Q1/6897 takes precedence)}
- C09C 1/48: Carbon black
- C12M 41/36: {of biomass, e.g. colony counters or by turbidity measurements (electrooptical investigation of individual particles G01N15/14, flow cytometers G01N15/1404)}
- G01N 2001/4088: {filtration}
- C12Q: MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS (immunoassay G01N33/53); COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
- C09C: TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES (treatment of materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone C04B14/00, C04B18/00, C04B20/00); PREPARATION OF CARBON BLACK {; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS}
- C12M: APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; {APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS}
- 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)

## Abstract

Exemplary embodiments pertain to a solution containing carbon black. The solution may be applied to a membrane filter of a microbial enumeration system as a post-rinse solution (i.e., after the membrane filter is rinsed with the sample of interest). The solution may reduce or suppress background autofluorescence, thereby improving detection and enumeration of colony forming units (CFUs) or other microbiological entities. The solution may be used in connection with a method for performing sample preparation for a microbial enumeration system. The carbon black solution may be manufactured according to a manufacturing process detailed herein.

## Claims

### Claim 1

A solution for a microbiological enumeration or detection system, comprising:
carbon black;
an emulsifier; and
water.

### Claim 2 (depends on 1)

The solution of claim 1, wherein the carbon black has an average particle size in the range of 6.0-8.0 microns.

### Claim 3 (depends on 1)

The solution of claim 1, wherein the emulsifier is polysorbate 80.

### Claim 4 (depends on 3)

The solution of claim 3, wherein the emulsifier is present in the solution at a concentration of about 1%.

### Claim 5 (depends on 1)

The solution of claim 1, wherein the carbon black is present in the solution at a concentration of at least 0.0001%.

### Claim 6 (depends on 1)

The solution of claim 1, wherein the carbon black is present in the solution at a concentration of at most 0.5%.

### Claim 7 (depends on 1)

The solution of claim 1, wherein the solution is a post-sample rinse solution.

### Claim 8 (depends on 1)

A method for performing sample preparation for a microbial enumeration or detection system, comprising:
adding a growth medium to a sample analysis container;
filtering the sample through a membrane;
filtering the solution of claim 1 through the membrane.

### Claim 9 (depends on 8)

The method of claim 8, further comprising adding a growth medium to a sample analysis container.

### Claim 10 (depends on 8)

The method of claim 8, further comprising filtering a rinse solution through the membrane.

### Claim 11 (depends on 8)

The method of claim 8, wherein the sample analysis container is a cassette, and further comprising filling the cassette with growth media.

### Claim 12

A method for manufacturing a carbon-black post-rinse solution, the method comprising:
mixing carbon black, an emulsifier, and water in a bulk solution mixer to form a mixed solution;
adding the mixed solution to a glass or plastic container;
capping the glass or plastic container; and
sterilizing the mixed solution.

### Claim 13 (depends on 12)

The method of claim 12, wherein capping the container comprises applying a screw-top cap with a septum to the container.

### Claim 14 (depends on 12)

The method of claim 12, wherein the emulsifier is polysorbate 80.

### Claim 15 (depends on 12)

The method of claim 12, wherein the carbon black is present in the solution at a concentration of at least 0.025%.

### Claim 16 (depends on 12)

The method of claim 12, wherein the carbon black is present in the solution at a concentration of at most 0.1%.