Biomedical Engineering Reference
In-Depth Information
A ist approach using a dendrimer to covalently functionalise CNTs for
gene delivery was reported in 2007 by Pan
et al
. Although it is not clear which
kind of nanotubes they used (it is not speciied whether they are single-,
double- or multi-walled), the reported results are interesting. The anti-
survivin oligonucleotide was anchored onto the polyamidoamine (PAMAM)
dendrimer and transfected into MCF-7 cells. This conjugate distributed
mainly in the cytoplasm, endosomes and lysosomes of the cells and was able
to release the antisense oligonucleotide, which then exerted its apoptotic
activity.
43
More recently, Herrero
et al.
reported a study in which a PAMAM
dendron was grown on the covalent functionalisation of MWCNTs. Different
generations were prepared (G0, G1 and G2, Fig. 3.9), and the free amines were
also alkylated by means of glycidyl trimethylammonium chloride, leading to
the presence of stable ammonium salts. These compounds have been used to
deliver a luorescent siRNA into HeLa cells, demonstrating the eficiency of
dendron-CNT conjugates as nucleic acid carriers, which increased with the
number of positive charges on the CNT surface.
44
N
OH
Cl
Cl
NH
3
NH
O
O
O
O
N
N
Cl
Cl
N
O
N
O
O
O
NH
3
N
H
N
OH
G0
N
Cl
OH
HN
Cl
N
NH
O
OH
Cl
N
NH
N
OH
HN
N
N
OH
O
Cl
O
HN
O
NH
NH
O
NH
N
N
N
Cl
Cl
NH
N
OH
O
N
N
O
O
O
N
OH
H
O
N
H
O
O
Cl
N
N
N
OH
HN
O
NH
Cl
O
O
N
N
N
O
O
N
O
O
N
Cl
N
N
H
H
N
NH
OH
N
OH
O
N
H
O
NH
O
NH
G1
G2
O
N
Cl
N
N
H
HN
N
OH
Cl
OH
O
NH
HN
N
OH
Cl
Figure 3.9
Structures of various dendron generations.
The same authors reported the use of MWCNT-NH
3
+
to deliver therapeutic
siRNA, and its intratumoural administration induced a delay in tumour
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