Biomedical Engineering Reference
In-Depth Information
Fig. 18 (a) Density of states of CdSe and capped CdSe QDs. (b) Charge density of capped CdSe
QDs. (Adapted from [
75
])
Fig. 19 (a) Optical absorption and (b) photoluminescence spectra of CdSe and CdSe QDs capped
with different concentration of cytosine. Sample
A
is as-prepared QDs and Samples
B
and
C
are
capped QDs. (Adapted from [
75
])
luminomagnets of ZnO:Fe. The luminomagnets were surface-immobilized with the
ligand folic acid. The relation between folic acid and cancer has been shown in
several published works [
77
]. For this, the luminomagnets were first surface-
modified with (3-aminopropyl)-trimethoxysilane (AEAPS) to form a self-assembled
monolayer, and subsequently conjugated with folic acid through amidation between
the carboxylic acid end groups on folic acid and the amine groups on the particle
surface. A very convenient coupling group is NHS (or its sulfo derivative, sulfo-
NHS), which can be easily generated by direct reaction of a carboxylic acid with
NHS in the presence of the dehydrating agent, 1-ethyl-3-(3-dimethylaminopropyl)
carbodiimide hydrochloride (EDC). The strategy of folic acid conjugation is dia-
grammatically shown in Fig.
20
.
