# US 2017/0281053 A1 · Method of fingerprinting with using carbogenic nanoparticle

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- Number: US 2017/0281053 A1
- Document ID: US20170281053A1
- Status: Published application
- Kind: A1
- Application number: 15/512,119
- Filed: 2015-09-18
- Published: 2017-10-05
- Earliest claimed: 2014-09-19
- Assignees: University of Central Lancashire
- Applicants: University of Central Lancashire
- Inventors: Antonios Kelarakis; Marta J Krysmann; Diogo Fernandes
- Web page: https://patentgrep.com/patent/US20170281053A1

## CPC

- A61B 5/1172: using fingerprinting
- A61B 5/117: Identification of persons (methods or arrangements for recognising patterns, e.g. fingerprints, G06F18/00, G06V40/00; identification of persons by analysing their voice or speech G10L17/00)
- G06V 40/12: Fingerprints or palmprints
- A61B 5/1171: based on the shapes or appearances of their bodies or parts thereof
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING

## Abstract

The present invention relates to a powder composition, in particular a fingerprint powder composition for the visualisation of latent fingerprints. Such fingerprint powder compositions comprise carbogenic nanoparticles which, when mixed with a suitable diluent (including any existing or future fingerprint powders), exhibits excitation-dependent emission properties which enable the fingerprint powder compositions and imagable fingerprint impression patterns formed thereform to be imaged in a variety of different colours by simply varying the wavelength(s) of any excitation radiation. As certain backgrounds can render visualisation of fingerprint impression patterns very difficult, having the flexibility to judiciously tune the foreground colour of the fingerprint impression patterns is a significant advantage since it permits instantaneous improvements in visualisation without needing to resort to using a different fingerprint powder. The invention also relates inter alia to corresponding methods and specialised apparatus for fingerprinting.

## Claims

### Claim 1

A method of fingerprinting, the method comprising:
i) coating a surface, comprising or suspected of comprising a latent fingerprint, with a fingerprint powder composition;
ii) developing an imagable impression pattern of the latent fingerprint within or from the coating of fingerprint powder composition;
iii) optionally tape-lifting said imagable impression pattern of the latent fingerprint from the surface;
iv) optionally imaging (e.g. photographing) the imagable impression pattern of the latent fingerprint;
wherein the fingerprint powder composition comprises carbogenic nanoparticles (CNPs) and a diluent;
wherein the fingerprint powder composition comprises at most 20 wt % carbogenic nanoparticles;
wherein the carbogenic nanoparticles or the carbonaceous material thereof has a carbon content of less than or equal to 70% C.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein the fingerprint powder composition comprises at least 0.1 wt % carbogenic nanoparticles and at most 10 wt % carbogenic nanoparticles.

### Claim 3 (depends on 1)

The method as claimed in claim 1, wherein the powder composition exhibits excitation-dependent emission.

### Claim 4 (depends on 1)

The method as claimed in claim 1, wherein the carbogenic core of the carbogenic nanoparticles is responsible for at least 50% of the quantum yield within a 1000 nm to 10 nm wavelength range.

### Claim 5 (depends on 1)

The method as claimed in claim 1, wherein the carbogenic nanoparticles are nanoparticles comprising, consisting essentially of, or consisting of a carbonaceous material(s) formed by the carbonization of a carbogenic precursor(s).

### Claim 6 (depends on 1)

The method as claimed in claim 1, wherein the carbogenic nanoparticles have a particle size between 1 and 50 nm.

### Claim 7 (depends on 1)

The method as claimed in claim 1, wherein the carbogenic nanoparticles are insoluble in water and hexane.

### Claim 8 (depends on 1)

The method as claimed in claim 1, wherein the carbon content of the carbonaceous material(s) of the carbogenic nanoparticles is greater than or equal to 42% C and less than or equal to 50% C.

### Claim 9 (depends on 1)

The method as claimed in claim 1, wherein the nitrogen content of the carbonaceous material(s) of the carbogenic nanoparticles is greater than or equal to 3% N and less than or equal to 15% N.

### Claim 10

(canceled)

### Claim 11 (depends on 1)

The method as claimed in claim 1, wherein the diluent comprises one or more metal oxide-based and/or silicon oxide-based species.

### Claim 12

(canceled)

### Claim 13 (depends on 1)

The method as claimed in claim 1, wherein the diluent is or comprises a fingerprint powder.

### Claim 14

(canceled)

### Claim 15

(canceled)

### Claim 16

(canceled)

### Claim 17

(canceled)

### Claim 18

(canceled)

### Claim 19

(canceled)

### Claim 20

(canceled)

### Claim 21

(canceled)

### Claim 22

(canceled)

### Claim 23

(canceled)

### Claim 24

(canceled)

### Claim 25

(canceled)

### Claim 26

(canceled)

### Claim 27

A fingerprint powder composition (FPC);
wherein the fingerprint powder composition comprises carbogenic nanoparticles (CNPs) and a diluent;
wherein the fingerprint powder composition comprises at most 20 wt % carbogenic nanoparticles;
wherein the carbogenic nanoparticles or the carbonaceous material thereof has a carbon content of less than or equal to 70% C.

### Claim 28

A method of preparing a fingerprint powder composition, the method comprising providing carbogenic nanoparticles and blending the carbogenic nanoparticles with a diluent;
wherein the fingerprint powder composition comprises at most 20 wt % carbogenic nanoparticles; and
wherein the carbogenic nanoparticles or the carbonaceous material thereof has a carbon content of less than or equal to 70% C.

### Claim 29 (depends on 28)

The method as claimed in claim 28, wherein providing carbogenic nanoparticles comprises carbonising one or more carbogenic precursors and/or carbogenic precursor groups to produce carbogenic nanoparticles comprising carbonaceous material(s).

### Claim 30 (depends on 28)

The method as claimed in claim 28, wherein carbonising the one or more carbogenic precursors and/or carbogenic precursor groups involves pyrolysis of the one or more carbogenic precursors and/or carbogenic precursor groups.

### Claim 31 (depends on 30)

The method as claimed in claim 30, wherein pyrolysis of the one or more carbogenic precursors and/or carbogenic precursor groups involves heating the one or more carbogenic precursors and/or carbogenic precursor groups at a temperature exceeding 180° C. but not exceeding 320° C.

### Claim 32 (depends on 30)

The method as claimed in claim 30, wherein after pyrolysis, the resulting carbonized materials are suitably purified, wherein purifying comprises one or more of:
Forming a dispersion of the CNPs within a solvent (e.g. water), suitably in a solvent within which the CNPs are (substantially) insoluble as defined herein;
Filtering the dispersion (e.g. to remove impurities that dissolve in the solvent);
Dialysing the dispersion (e.g. using an appropriate dialysis membrane or tubing membrane), suitably at a molecular weight cut off of at least 500 Daltons (Da), suitably at least 1000 Da, suitably at least 3000 Da, suitably at about 3500 Da, suitably for a time sufficient to remove (substantially) all impurities and/or by-products having a molecular weight below the cut off;
Refluxing in acid (e.g. 3M HNO3);
Centrifuging to remove large particles.

### Claim 33

(canceled)

### Claim 34 (depends on 29)

The method as claimed in claim 29, wherein the carbogenic precursor(s) and/or carbogenic group(s) comprise the elements carbon, hydrogen, oxygen, and nitrogen.

### Claim 35 (depends on 34)

The method as claimed in claim 34, wherein the carbogenic precursor(s) and/or carbogenic group(s) comprise at least a hydroxyl, a carboxy, and an amino group, and/or a suitable salt and/or derivative thereof.

### Claim 36 (depends on 35)

The method as claimed in claim 35, wherein the carbogenic precursor(s) and/or carbogenic group(s) comprise citric acid, ethanolamine, and/or one or more products derived from a condensation reaction between citric acid and ethanolamine, and/or a salt and/or derivative thereof.

### Claim 37 (depends on 33, 34, 35, 36)

The method as claimed in claims 33 to 36, wherein the carbogenic precursor(s) and/or carbogenic group(s) comprise biomass and/or one or more carbogenic precursor(s) and/or carbogenic group(s) extracted from biomass.

### Claim 38

(canceled)

### Claim 39 (depends on 28)

A fingerprint powder composition obtainable by the method of preparing a fingerprint powder composition as claimed in claim 28.

### Claim 40

(canceled)

### Claim 41 (depends on 1)

The method as claimed in claim 1, wherein the carbonaceous material(s) of the carbogenic nanoparticles has a nitrogen content greater than or equal to 1% N and less than or equal to 11% N.

### Claim 42 (depends on 1)

The method as claimed in claim 1, wherein the carbonaceous material(s) of the carbogenic nanoparticles further comprise nitrogen.

### Claim 43 (depends on 42)

The method as claimed in claim 42, wherein the carbonaceous material(s) of the carbogenic nanoparticles has a nitrogen content greater than or equal to 1% N and less than or equal to 11% N.

### Claim 44 (depends on 28)

The fingerprint powder composition of claim 28, wherein the carbonaceous material(s) of the carbogenic nanoparticles further comprises nitrogen.

### Claim 45 (depends on 44)

The fingerprint powder composition as claimed in claim 44, wherein the carbonaceous material(s) of the carbogenic nanoparticles has a nitrogen content greater than or equal to 1% N and less than or equal to 11% N.

### Claim 46 (depends on 28)

The method as claimed in claim 28, wherein the carbonaceous material(s) of the carbogenic nanoparticles further comprise nitrogen.

### Claim 47 (depends on 46)

The method as claimed in claim 46, wherein the carbonaceous material(s) of the carbogenic nanoparticles has a nitrogen content greater than or equal to 1% N and less than or equal to 11% N.