Biomedical Engineering Reference
In-Depth Information
4.2.2 Selecve Chemical Ligaon
An interesting example of this type of functionalisation has been provided
by Pantarotto
et al.
,
7
who attached a peptide (i.e., the epitope corresponding
to a speciic sequence of the VPI protein of the foot-and-mouth disease
virus [FMDV]) to CNTs and investigated its immunogenic properties. CNTs
underwent the 1,3-dipolar cycloaddition of azomethine ylides, while the
peptide was coupled to the amino group of functionalised CNTs via a peptide
bond (Scheme 4.2).
7
SWCNTs with a free amino group -NH
2
and eventually
the aminoacid lysine were subsequently modiied with a maleimido group,
which allowed for linking the FMDV peptide bearing an additional cysteine
(at the N terminus) necessary for a selective chemical ligation.
O
1)
O
O
1) (CH
2
O)
n
, DMF
N
NH
3
+
Cl
-
O
N
O
O
O
O
NHBoc
N
HOOC
N
H
O
O
DI EA, DMF
12 0° C, 3 day s
2) FMDV-Cys-Ac
H
2
O
2) HCl
1
2
O
O
O
Ac
NH
3
+ CF
3
CO O
-
O
N
H
O
N
NH
O
O
S
Cys
N
N
O
FM DV
NH
3
+
CF
3
CO O
-
O
4
5
N
O
O
O
O
N
FMDV
O
O
O
S
Cys
N
N
O
H
O
Ac
N
O
O
O
Ac
N
N
Cys
S
O
O
FM DV
6
Scheme 4.2
Synthesis of mono- (compound
4
) and bis-(compound
6
)-derivatised
CNTs with the epitope of the foot-and-mouth disease virus (FMDV).
The covalent functionalisation of CNTs to conjugate the peptides was a
necessary step, as demonstrated by the observation that the simple mixture
of the two components did not elicit high antibody titers. When the CNT-
peptide complex was incubated with speciic monoclonal and polyclonal
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