# US 11,079,387 B2 · Length-based carbon nanotube ladders

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- Number: US 11,079,387 B2
- Document ID: US11079387B2
- Status: Granted
- Kind: B2
- Application number: 16/383,552
- Filed: 2019-04-12
- Published: 2019-10-17
- Granted: 2021-08-03
- Earliest claimed: 2018-04-12
- Applicants: Zahra Borzooeian; Mohammad E. Taslim
- Inventors: Zahra Borzooeian; Mohammad E. Taslim
- Web page: https://patentgrep.com/patent/US11079387B2

## CPC

- G01N 33/581: {with enzyme label (including co-enzymes, co-factors, enzyme inhibitors or substrates)}
- C01B 32/158: Carbon nanotubes
- C01B 32/168: After-treatment
- G01N 27/44726: {using specific dyes, markers or binding molecules}
- C01B 2202/02: Single-walled nanotubes
- C01B 2202/06: Multi-walled nanotubes
- C01B 2202/34: Length
- G01N 2550/00: Electrophoretic profiling, e.g. for proteome analysis
- 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)
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}

## Abstract

In one aspect, the present invention is generally directed to methods for measuring distribution of lengths of a collection of carbon nanotubes. In particular, the present teachings provide an indicator for length-based separation of carbon nanotubes (CNTs) via conjugation of one or more biomolecules onto the surfaces of the nanotubes. As discussed in more detail below, in some embodiments, such a method can include conjugating a biomolecule to the carbon nanotubes and subject the conjugated carbon nanotubes to silver-stained gel electrophoresis to separate the conjugated carbon nanotubes based on their lengths.

## Claims

### Claim 1

A method of determining distribution of lengths of a collection of carbon nanotubes, comprising:
conjugating a biomolecule to surfaces of at least a portion of the carbon nanotubes,
separating the conjugated carbon nanotubes having different lengths based on their different charge and size-dependent mobilities,
wherein said conjugating step comprises carboxylating said carbon nanotubes, and
wherein said conjugating step further comprises covalently linking said biomolecule to COOH moieties of said carboxylated carbon nanotubes.

### Claim 2 (depends on 1)

The method of claim 1, wherein said biomolecule comprises a protein.

### Claim 3 (depends on 2)

The method of claim 2, wherein said biomolecule comprises an enzyme.

### Claim 4 (depends on 3)

The method of claim 3, wherein said biomolecule comprises lysozyme.

### Claim 5 (depends on 4)

The method of claim 4, wherein said lysozyme comprises chicken egg white lysozyme.

### Claim 6 (depends on 1)

The method of claim 1, wherein said step of conjugating the biomolecule to said carbon nanotubes comprises covalently linking the biomolecule to surfaces of said carbon nanotubes.

### Claim 7 (depends on 6)

The method of claim 6, wherein said covalently linking of the biomolecule to surfaces of said carbon nanotubes is achieved via linking agent.

### Claim 8 (depends on 7)

The method of claim 7, wherein said linking agent comprises a carboiimide reagent.

### Claim 9 (depends on 8)

The method of claim 8, wherein said carbodiimide reagent is N-ethyl-N′-(3-(dimethylamino)propyl)carbodiimide.

### Claim 10 (depends on 1)

The method of claim 1, wherein said step of separating the conjugated carbon nanotubes comprises subjecting said carbon nanotubes to gel electrophoresis.

### Claim 11 (depends on 10)

The method of claim 10, wherein said gel electrophoresis comprises a silver-stained gel electrophoresis.

### Claim 12 (depends on 11)

The method of claim 11, wherein said gel electrophoresis comprises sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).

### Claim 13

A method of determining distribution of lengths of a collection of carbon nanotubes, comprising:
conjugating a biomolecule to surfaces of at least a portion of the carbon nanotubes,
separating the conjugated carbon nanotubes having different lengths based on their different charge and size-dependent mobilities,
wherein said step of separating the conjugated carbon nanotubes comprises subjecting said carbon nanotubes to gel electrophoresis,
wherein said step of subjecting the conjugated carbon nanotubes to gel electrophoresis separates the conjugated carbon nanotubes into separate bands corresponding to their lengths.

### Claim 14 (depends on 13)

The method of claim 13, wherein said carbon nanotubes in each band have substantially similar length.

### Claim 15 (depends on 1)

The method of claim 1, wherein said carbon nanotubes comprise single walled carbon nanotubes (SWCNTs).

### Claim 16 (depends on 1)

The method of claim 1, wherein said carbon nanotubes comprise multi-walled carbon nanotubes.

### Claim 17 (depends on 13)

The method of claim 13, further comprising analyzing an intensity of each band generated by said gel electrophoresis to determine a length of carbon nanotubes associated with said band.

### Claim 18 (depends on 17)

The method of claim 17, wherein said step of analyzing an intensity of each band comprises relating length of carbon nanotubes associated with each band to an intensity of said band corresponding to the following relation:
L
=
d
⁢
⁢
exp
⁡
[
3
⁢
πημ
q
⁡
(
d
)
⁢
e
-
2
⁢
ln
⁢
⁢
2
+
1
]
,
wherein,
L is the calculated length,
D is mean diameter,
η is viscosity,
q(d) is persistence length,
μ is mobility,
e is the electron charge, and
d is the average diameter of each carbon nanotube.

### Claim 19 (depends on 10)

The method of claim 10, further comprising sonicating said conjugated carbon nanotubes prior to subjecting them to gel electrophoresis.

### Claim 20

A method of determining average length of a sample of carbon nanotubes, comprising:
labelling each of a plurality of carbon nanotubes with a biological moiety, to provide labelled carbon nanotubes;
subjecting the labelled carbon nanotubes to gel electrophoresis, to provide an electrophoresis gel comprising the labelled carbon nanotubes;
treating the electrophoresis gel comprising the labelled carbon nanotubes with a visualizing agent to provide stained, labelled carbon nanotubes;
measuring at a plurality of locations in the electrophoresis gel the visual intensity of the stained, labelled carbon nanotubes;
wherein the average length of the stained, labelled carbon nanotubes is a function of their distance travelled in the electrophoresis gel.

### Claim 21 (depends on 20)

The method of claim 20, wherein said carbon nanotubes are single-walled carbon nanotubes.

### Claim 22 (depends on 20)

The method of claim 20, wherein said carbon nanotubes are multi-walled carbon nanotubes.

### Claim 23 (depends on 20)

The method of claim 20, wherein said biological moiety comprises an enzyme.

### Claim 24 (depends on 20)

The method of claim 20, wherein said biological moiety comprises lysozyme.

### Claim 25 (depends on 24)

The method of claim 24, wherein said lysozyme comprises chicken egg white lysozyme.

### Claim 26 (depends on 20)

The method of claim 20, wherein said step of labelling the carbon nanotubes with said biological moiety comprises covalently linking the biological moiety to surfaces of said carbon nanotubes.

### Claim 27 (depends on 20)

The method of claim 20, wherein said covalently linking of the biological moiety to surfaces of said carbon nanotubes is achieved via a linking agent.

### Claim 28 (depends on 27)

The method of claim 27, wherein said linking agent comprises a carboiimide reagent.

### Claim 29 (depends on 28)

The method of claim 28, wherein said carbodiimide reagent is N-ethyl-N′-(3-(dimethylamino)propyl)carbodiimide.

### Claim 30 (depends on 20)

The method of claim 20, further comprising analyzing an intensity of each band generated by said gel electrophoresis to determine a length of carbon nanotubes associated with said band.