# US 12,108,759 B2 · Synthesis of antimicrobial carbon dots and uses thereof

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

- Number: US 12,108,759 B2
- Document ID: US12108759B2
- Status: Granted
- Kind: B2
- Application number: 17/290,910
- Filed: 2019-10-31
- Published: 2022-02-03
- Granted: 2024-10-08
- Earliest claimed: 2018-11-04
- Assignees: B.G. Negev Technologies and Applications Ltd., At Ben-Gurion University
- Applicants: B.G. Negev Technologies & Applications Ltd., at Ben-Gurion University
- Inventors: Raz Jelinek; Sagarika Bhattacharya; Gil Otis
- Web page: https://patentgrep.com/patent/US12108759B2

## CPC

- A01N 25/26: in coated particulate form
- A61K 31/155: Amidines ([IMAGE cpc-sch-A61K-1029.gif]), e.g. guanidine (H2N—C(=NH)—NH2), isourea (N=C(OH)—NH2), isothiourea (—N=C(SH)—NH2)
- A01N 35/10: containing a carbon-to-nitrogen double bond
- A61K 47/6923: {the form being an inorganic particle, e.g. ceramic particles, silica particles, ferrite or synsorb}
- A61K 47/6929: {the form being a nanoparticle, e.g. an immuno-nanoparticle}
- A61P 31/04: Antibacterial agents
- G01N 33/52: Use of compounds or compositions for colorimetric, spectrophotometric or fluorometric investigation, e.g. use of reagent paper {and including single- and multilayer analytical elements (immunological elements G01N33/54386; involving labelled immunochemicals G01N33/58; for haemoglobin or occult blood G01N33/72)}
- G01N 33/582: {with fluorescent label}
- A61K 9/5115: {Inorganic compounds}
- A01N: PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF (preservation of food or foodstuff A23); BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES (preparations for medical, dental or toiletry purposes which kill or prevent the growth or proliferation of unwanted organisms A61K); PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- A61P: SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- 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

The present invention relates to antibacterial carbon dots, having aminoguanidine functionality on their outermost surface. The invention further relates to the synthesis of said antibacterial carbon dots, and to the uses of these carbon dots for inhibiting a biofilm formation in the presence of said carbon dots and as fluorescent labeling markers for specific bacteria.

## Claims

### Claim 1

Antimicrobial carbon-dots (C-dots) having at least one aminoguanidine functional group on their outer surface, wherein said C-dots are characterized in having a maximal emission at a wavelength of about 480 nm upon excitation at a wavelength of 390 nm, and wherein said antimicrobial C-dots inhibit the growth of Pseudomonas aeruginosa.

### Claim 2 (depends on 1)

The antimicrobial C-dots according to claim 1, wherein said C-dots have a size between 3.5 and 5 nm in diameter.

### Claim 3 (depends on 1)

The antimicrobial C-dots according to claim 1, wherein said C-dots are obtained by reacting a carboxylic acid with an aminoguanidine precursor, and wherein said C-dots are characterized by having an x-ray photoelectron spectrum (XPS spectrum) showing retention of the aminoguanidine and carboxylic acid residues by exhibiting:
(a) a Cls spectrum featuring deconvoluted peaks at 284 eV, 285.2 eV, 286.5 eV, and 288.5 eV corresponding to C═C, C—N, C—O/C═N and C═O bonds; and
(b) a N1s spectrum featuring deconvoluted peaks at 399.7 eV and 400.7 eV ascribed to C—N and C═N bonds.

### Claim 4 (depends on 1)

The antimicrobial C-dots according to claim 1, wherein said C-dots are characterized by having quantum yield of about 3% in deionized water.

### Claim 5 (depends on 1)

The antimicrobial C-dots according to claim 1, wherein said C-dots are characterized by having a zeta potential value higher than about −16 mV in phosphate-buffered saline (PBS buffer) at pH=7.4.

### Claim 6 (depends on 5)

The antimicrobial C-dots according to claim 5, wherein said C-dots have a zeta potential between −1 to −15 mV in PBS buffer at pH=7.4.

### Claim 7 (depends on 6)

The antimicrobial C-dots according to claim 6, wherein said C-dots have a zeta potential of about −2 mV in PBS buffer at pH=7.4.

### Claim 8 (depends on 6)

The antimicrobial C-dots according to claim 6, wherein said C-dots have a zeta potential of about −2 mV in PBS buffer at pH=7.4.

### Claim 9

A method for inhibiting the formation of a biofilm and/or disrupting the propagation of a biofilm comprising contacting antimicrobial C-dots having at least one aminoguanidine functional group on their outer surface with biofilm forming bacterial cells.

### Claim 10 (depends on 9)

The method according to claim 9, wherein the bacterial cells are Pseudomonas aeruginosa cells.

### Claim 11 (depends on 9)

The method according to claim 9, wherein the C-dots are characterized by having a zeta potential value higher than about −16 mV in PBS buffer at pH=7.4.

### Claim 12 (depends on 11)

The method according to claim 11, wherein said C-dots have a zeta potential between −1 to −15 mV in PBS buffer at pH=7.4.

### Claim 13

A method for selective bacterial cell labeling, comprising the steps of (A) contacting bacterial cells sought to be labeled with fluorescent C-dots having at least one aminoguanidine functional group on their outer surface at a concentration range of between about 0.1 mg/ml to about 1 mg/ml; and (B) removing excess C-dots; thereby providing precise cell labeling.

### Claim 14 (depends on 13)

The method of claim 13, wherein the concentration of the bacteria in step (A) ranges between about OD600 0.1 to about 1.

### Claim 15 (depends on 14)

The method of claim 14, wherein the aminoguanidine precursor is aminoguanidine hydrochloride.

### Claim 16

A method for preparing antimicrobial C-dots having at least one aminoguanidine functional group on their outer surface, wherein said method comprises a step of reacting a carbonaceous molecule with an aminoguanidine precursor in aqueous media under heating, wherein a mass ratio between said aminoguanidine precursor and said carbonaceous molecule is between about 2.5:1 to about 1.5:1.

### Claim 17 (depends on 16)

The method according to claim 16, wherein said carbonaceous molecule is selected from the group consisting of carboxylic acids, sugars, amino acids, ascorbic acid and peptides.

### Claim 18 (depends on 16)

The method according to claim 16, wherein said carbonaceous molecule is a carboxylic acid.

### Claim 19 (depends on 18)

The method according to claim 18, wherein the carbonaceous molecule is citric acid.

### Claim 20 (depends on 19)

The method according to claim 19, wherein the mass ratio between aminoguanidine precursor to citric acid is about 2:1.

### Claim 21 (depends on 16)

The method according to claim 16, wherein the heating occurs at a temperature of between about 120 to about 180 degrees Celsius.

### Claim 22 (depends on 16)

An antimicrobial composition comprising C-dots having at least one aminoguanidine functional group on their outer surface, wherein said C-dots are characterized (i) in having a maximal emission at a wavelength of about 480 nm upon excitation at a wavelength of 390 nm, and wherein said antimicrobial C-dots inhibit the growth of Pseudomonas aeruginosa; or (ii) as prepared by a method according to claim 16.