Biomedical Engineering Reference
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For a qualitative assessment of the interactions between the SWCNT-ACD-
PPR conjugate and complementary DNA sequences, temperature-dependent
fluorescence titration experiments were performed. The results showed
that the association of ACD-PPR with complementary DNA gave negative
enthalpic changes (
∆H
°
= -23.6 kJ/mol) and positive entropic changes (T
∆S
°
= 2.7 kJ/mol). The values might be associated with the van der Waals and
hydrophobic interactions, which seemed to be the main driving forces and
also justiied more favourable contributions once the highly hydrophobic
SWCNTs were added. It was also proved that the SWCNT-ACD-PPR conjugate
not only acted as a DNA carrier but also exhibited a good ability to cleave
DNA, similar to the already reported photoinduced DNA-cleavage mechanism
for cyclodextrin-fullerene conjugates.
34-36
A supramolecular architecture was recently proposed by Liu
et al.
,
37
who
strategically modiied chitosan (CHIT) with CD and multi-walled carbon
nanotubes (MWCNTs) to provide a multifunctional gene delivery system (Fig.
5.10). CHIT itself has been considered a promising non-viral gene carrier, on
(a)
(c)
MWCNTs,
HCl, sonic. 24 h
CDCHIT
MWCNTCDCHIT
11
PY-ADA
NH
2
15
OH
+
O
12
13
DCC, HOBt,CH
2
Cl
2
(b)
(d)
CDCHITPYADA
MWCNTCDCHITPYADA
14
16
Figure 5.10
Preparation of the supramolecular architecture MWCNT-β-CD-CHIT-PY-
ADA. Modiied from Liu
et al.
37
with permission. See also Colour Insert.
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