BIOMEDICAL APPLICATIONS I: DELIVERY OF DRUGS - Carbon Nanotubes: From Bench Chemistry to Promising Biomedical Applications - page 24

surface of carbon nanotube, indicating that different chemical procedures
can be adopted to introduce several groups and functionalities. 34,48-55
In Scheme 2.1 are briely reported a few approaches to functionalise CNTs
which can be performed in a covalent or non-covalent manner. 56-71

b a

a

b

N N

O

O O

O

N

C

CO OH

N

HOOC

O

c d

c d

Scheme 2.1 Examples of functionalisations on CNTs' sidewalls and tips for drug delivery
purposes: (a) non-covalent, (b) covalent (1,3-dipolar cycloaddition), (c) “defect” and
(d) covalent (via oxidation). See also Colour Insert.

CNTs can be also considered good DDS after the experimental observation
that SWCNTs are able to encapsulate small molecules. This can be a new
approach in DDS; in fact encapsulation of drugs into the nanotubes can
prevent their inactivation or degradation and increase their half time 72-74
(Scheme 2.2).

Scheme 2.2 Encapsulation of bioactive molecules in the inner cavity of CNTs. See
also Colour Insert.

However, even though a lot of diversiied CNT functionalisations have
been successfully achieved, only a few examples of delivery of small molecules
(antibacterial, antiviral and anticancer agents) using f -CNTs are currently
reported in the literature (Table 2.1). 55,56,66,75-89