Biomedical Engineering Reference
In-Depth Information
NH
3
+
Cl
-
SW CNT-COOH
f
-SW CNT (1a)
O
O
NH
3
+
Cl
-
O
O
NH
OH
O
NH
3
+
Cl
-
O
(C O Cl)
2
,62 ,24h
62°,
62°,
O
O
THF (dry), 62
, 48 h
O
H
OH
3M HNO
3
,120 ,48h
Sonication 1 h, 120
120°,
4.0MHClindioxane
mono-BOC-TEG
O
120°
48 h
NH
OH
3M HNO
3
,
sonication2h,120
12h
sonication 2h, 120°
O
O
24
23
5
HOBt, EDCxHCl, DIEA
62°,
(COCl)
2
,62 ,24h
THF (dry), 62
N
NH
2
N
62°,
, 48 h
HOOC
26
N
N
N
H
2
N
N
N
NH
2
NH
2
DMF:DCM (1:1), rt, 48 h
N
N
N
25
N
N
HN
O
N
NH
2
O
O
N
N
O
N
N
H
O
NH
2
N
NH
HN
N
N
O
O
N
N
O
NH
2
NH
2
O
O
N
N
N
NH
N
H
N
N
O
NH
N
O
NH
2
N
O
HN
NH
N
N
O
O
f
-SW CN T (2a)
f
-SW C N T (2b)
27
28
Figure 5.15
Scheme of synthesis of functionalised SWCNTs complexed with adenine
nucleobases.
Abbreviations
: TEG, tri-ethylene glycol; EDCxHCl, 1-ethyl-3-(3-dimethy
laminopropyl)carbodiimide hydrochloride (1.5 eq.); HOBt,
N
-hydroxybenzotriazole
(1.5 eq.); DIEA, diisopropylethylamine (3 eq.); DMF, dimethylformamide; DCM,
dichloromethane.
Another covalent conjugation between DNA and CNTs was proposed
by Hamers,
56
who treated oxidised SWCNTs with thionyl chloride irst and
then ethylenediamine to produce free amino groups that were subsequently
reacted with the heterobifunctional cross-linker succinimidyl 4-(
N
-maleim
idomethyl)cyclohexane-1-carboxylate (SMCC) and inally linked to thiol-
terminated DNA
(Fig. 5.18).
This procedure helped improve the quality of
the samples in several ways: First of all, the covalent binding reduced the Ni
contamination from 19% to 4 % by weight, and the yttrium contamination
from 4.8% to 0.75%. Moreover, the use of SMCC as a covalent linker led to a
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