2.4. Synthesis of dendrimer functionalized SPIONs
PAMAM dendrimer was coated on the surface of APTES modified SPIONs in
two steps according to the previous reports with some modification
(Liu, Guo, Jin, Yang, & Wang, 2008;
Pan et al., 2007;
Tajabadi et al., 2013). In the first
step, 10 ml of 5% (w/v) APTES modified SPIONs in methanol was sonicated
for 20 minutes. Then, 50 ml of 20% (v/v) methyl acrylate was added
dropwise to the stirring solution at room temperature for 24 hrs. The
resultant solution was washed with methanol five times and separated
with a magnetic magnet. In the second step, 10ml of 50% (v/v)
ethylenediamine was added to the purified magnetic nanoparticles and
stirred for three h and was then placed in the ultrasonic water bath for
one h. The final product was sedimented by a magnetic magnet and washed
with methanol five times. After completing the second step, a full
generation of dendrimers was formed on amine-functionalized magnetic
nanoparticles. These steps were repeated two times to achieve the third
generation of dendrimer on SPIONs. Fig 1, demonstrates the schematic
representation of the synthesis reaction of SPION-G3.