# US 11,994,457 B2 · Methods for detection of silver nanoparticles

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

- Number: US 11,994,457 B2
- Document ID: US11994457B2
- Status: Granted
- Kind: B2
- Application number: 17/585,781
- Filed: 2022-01-27
- Published: 2023-07-27
- Granted: 2024-05-28
- Earliest claimed: 2022-01-27
- Assignees: City University of Hong Kong
- Applicants: City University of Hong Kong
- Inventors: Wenxiong Wang; Anqi Sun
- Web page: https://patentgrep.com/patent/US11994457B2

## CPC

- G01N 15/06: Investigating concentration of particle suspensions (by weighing G01N5/00; investigating sedimentation of particle suspensions G01N15/04; investigating individual particles G01N15/10)
- G01N 15/1434: Optical arrangements
- C12Q 1/02: involving viable microorganisms
- G01N 15/075: by optical means
- G01N 2015/0681: {Purposely modifying particles, e.g. humidifying for growing}
- G01N 2015/0687: {in solutions, e.g. non volatile residue}
- G01N 2015/1006: {for cytology}
- 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)
- 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

## Abstract

A method for detection of the presence and/or quantities of silver nanoparticles in a specimen is shown. The method includes the steps of a) providing a detection organism suspended in a medium, b) treating the detection organism with zinc ions thus effecting auto-fluorescence therefrom, and then measuring degree of fluorescence of the detection organism suspended medium, c) adding the specimen to the detection organism suspended medium, treating the detection organism therein with the specimen for a period of time, and measuring change of fluorescence of the detection organism-suspended medium over time, d) calculating amount of silver ions intracellularly dissolved from the silver nanoparticles and accumulated in the detection organism in view of the change of fluorescence, and e) extrapolating quantity of silver nanoparticles in the specimen in view of the change of fluorescence and the amount of the intracellularly dissolved silver ions.

## Claims

### Claim 1

A method for detection of presence and/or quantities of silver nanoparticles in a specimen when the silver nanoparticles have a size ranging from 4.5 to 9 nm or with an average size of 7 nm in diameter and the silver nanoparticles have a concentration of 8.9 to 75 μg/L, comprising:
providing a detection organism suspended in a medium and yielding a detection organism-suspended medium, wherein the detection organism auto-fluoresces in the presence of zinc ions and de-fluoresces in the presence of silver ions, wherein the detection organism is an adenine deficient Saccharomyces cerevisiae, and wherein the biomass of the adenine deficient yeast indicative of the concentration thereof in the detection organism-suspended medium ranges from OD600=0.005 to OD600=0.02,
treating the detection organism with zinc ions thus effecting auto-fluorescence therefrom, and then measuring a degree of fluorescence of the detection organism-suspended medium,
adding the specimen to the detection organism-suspended medium, treating the detection organism therein with the specimen for a period of time, and measuring a change of fluorescence of the detection organism-suspended medium over time,
calculating a concentration of silver ions intracellularly dissolved from the silver nanoparticles and accumulated in the detection organism in view of the change of fluorescence, and
extrapolating the concentration of silver nanoparticles in the specimen in view of the change of fluorescence and the concentration of the intracellularly dissolved silver ions.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein the Saccharomyces cerevisiae is strain W303.

### Claim 3 (depends on 2)

The method as claimed in claim 2, wherein the adenine deficient Saccharomyces cerevisiae is a wildtype strain.

### Claim 4 (depends on 1)

The method as claimed in claim 1, wherein the concentration of the intracellularly dissolved silver ions correlates to the concentration of the silver nanoparticles in the specimen.

### Claim 5 (depends on 4)

The method as claimed in claim 4, wherein the method detects silver nanoparticles with an average size of 7 nm in diameter.

### Claim 6 (depends on 1)

A method as claimed in claim 1, wherein the biomass of the adenine deficient yeast is OD600=0.005.

### Claim 7 (depends on 1)

The method as claimed in claim 1, wherein, treating the detection organism with zinc ions, comprises a step of optimizing the concentration of the zinc ions in the detection organism-suspended medium to 0.025-0.1 μM for at least 1 hour.

### Claim 8 (depends on 7)

The method as claimed in claim 7, wherein the concentration of the zinc ions in the detection organism-suspended medium is optimized to 0.05 μM.

### Claim 9 (depends on 1)

The method as claimed in claim 1, wherein the time period of the detection organism being treated with the specimen is 30-60 mins, and wherein measurement of the change in fluorescence is taken during and after the period of time.

### Claim 10 (depends on 9)

The method as claimed in claim 9, wherein the period of time is 30 mins.