# US 2020/0400641 A1 · Lanthanide-Doped Nanoparticle Compositions for Detecting Microorganisms

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- Number: US 2020/0400641 A1
- Document ID: US20200400641A1
- Status: Published application
- Kind: A1
- Application number: 17/009,108
- Filed: 2020-09-01
- Published: 2020-12-24
- Earliest claimed: 2016-02-13
- Assignees: BacTrac Technologies LLC
- Applicants: BacTrac Technologies LLC
- Inventors: Vivian Hsiao; Vincent Mar
- Web page: https://patentgrep.com/patent/US20200400641A1

## CPC

- G01N 33/12: Meat; Fish
- C09K 11/7777: {Phosphates}
- C12Q 1/06: Quantitative determination
- 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)
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- 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 particulate lanthanide-doped material comprising an inorganic host phosphor and a lanthanide ion dopant. With the lanthanide-doped material being in an oxidized state, photoluminescence is suppressed. Photoluminescence of the material can be activated by the presence of a reducing substance that reduces the lanthanide-doped material in a redox interaction. The lanthanide-doped material can be used for biodetection (e.g. detecting the presence of microorganisms in a sample). This could have numerous applications, such as detecting the presence of contaminating microorganisms in a sample (e.g. in a food or cosmetic product).

## Claims

### Claim 1

A method of biodetection of bacteria in a food product sample, comprising:
(a) having a particulate lanthanide-doped inorganic material comprising:
an inorganic host phosphor in a first oxidation state and capable of being reduced to a second oxidation state, the second oxidation state being a relatively lower oxidation state than the first oxidation state;
a lanthanide ion dopant dispersed in the inorganic host phosphor;
(b) having a sample container in which at least a portion of the sample container is optically transparent;
(c) putting the food sample into the sample container;
(d) promoting growth of bacteria in the food product sample by adding bacterial growth medium into the sample container, or wherein the sample container already contains bacterial growth medium;
(e) contacting the food product sample with the lanthanide-doped inorganic material by adding the lanthanide-doped inorganic material to the sample container, or wherein the wherein the sample container already contains the lanthanide-doped inorganic material;
(f) incubating the sample food product at a temperature that is above 20° C.;
(g) exposing the lanthanide-doped inorganic material to excitation light; and
(h) detecting for emission of luminescent light from the lanthanide-doped inorganic material.

### Claim 2 (depends on 1)

The method of claim 1, wherein the step of detecting for light emission comprises making a detection reading after a delay of time from when the exposure of the lanthanide-doped inorganic material to excitation light is completed.

### Claim 3 (depends on 2)

The method of claim 2, wherein the delay of time is at least 100 nanoseconds after the time when exposure to excitation light is completed.

### Claim 4 (depends on 2)

The method of claim 2, wherein the delay of time is at least 500 nanoseconds after the time when exposure to excitation light is completed.

### Claim 5 (depends on 2)

The method of claim 2, wherein the delay of time is at least 1 microsecond after the time when exposure to excitation light is completed.

### Claim 6 (depends on 1)

The method of claim 1, wherein the step of detecting for light emission comprises making multiple detection readings over an interval of time.

### Claim 7 (depends on 6)

The method of claim 6, wherein the interval of time is in a range from 2-72 hours after beginning the incubation.

### Claim 8 (depends on 6)

The method of claim 6, wherein the interval of time is in a range from 2-24 hours after beginning the incubation.

### Claim 9 (depends on 6)

The method of claim 6, wherein the interval of time is in a range from 2-12 hours after beginning the incubation.

### Claim 10 (depends on 6)

The method of claim 6, wherein each of the multiple detection readings is separated by a time gap in the range of 5 minutes to 1 hour.

### Claim 11 (depends on 1)

The method of claim 1, wherein the bacteria produce and release a metabolite that undergoes redox reaction with the host phosphor and causes the host phosphor to become reduced to the second oxidation state.

### Claim 12 (depends on 11)

The method of claim 11, wherein reduction of the host phosphor activates the lanthanide-doped inorganic material for luminescence.

### Claim 13 (depends on 6)

The method of claim 6, further comprising plotting the luminescence output over time and identifying a pattern of bacterial growth going from a lag phase to an exponential phase of growth.

### Claim 14 (depends on 13)

The method of claim 13, further comprising calculating the initial number of bacteria present in the food product sample based on the transition from the lag phase to the exponential phase of growth.