
496 Nanosensors: Physical, Chemical, and Biological
O
OH
I
C
N
N
+
NH
+
NH
Cl
–
Cl
–
II
NH
2
O
I
II
N
H
H
2
O
O
I
OH
N
NH
O
O
I
N
O
O
OH
EDC (1-ethyl-3-[3-dimethylaminopropyl]
carbodiimide hydrochloride)
Carboxylate
molecule
Unstable reactive o-
acylisourea ester
Stable amide bond
Regenerated carboxyl
group
N-hydroxysuccinimide
(NHS)
I
O
O
N
O
O
I
II
O
N
H
NH
2
I
Semi-stable amine
reactive NHS ester
Stable amide bond
FIGURE 8.17
Esterication of the carboxylic groups with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide
(EDC) and N-hydroxysuccinimide (NHS). EDC is a water-soluble derivative of carbodiimide
that catalyzes the formation of amide bonds between carboxylic acids or phosphates and
ami