Biomedical Engineering Reference
In-Depth Information
Fig. 3.2
Cell viabilities of (
a
) MTT and (
b
) XTT assay results after treatment with various
concentrations of SPIONs. (
c
) Induced lysosomes in Captan-2, Panc-1, Hela, and Jurkat cells
obtained by their interactions with SPIONs. In the liver lysosomes assay, the lysosomes and nucleus
are seen as
red
and
blue
fluorescence, respectively. Induced ROS level in Captan-2, Panc-1, Hela,
and Jurkat cells is obtained by their interactions with SPIONs. In intracellular ROS assay, the ROS
level and nucleus are seen as
green
and
blue
fluorescence, respectively (Adapted from [
16
])
increases the circulation lifetime in the blood. Apolipoproteins also promote the
interaction with lipoprotein receptors which enhances the transport across the
blood-brain barrier [
1
,
4
].
NPs functionalized with hydrophilic polymers show improved circulation
properties and decreased macrophage recognition of many types of nanoparticles
[
5
]. For example, polyethylene glycol (PEG), pluronic F68, or poloxamer (block
copolymer of polyethylene oxide and polypropylene oxide) have been studied.
Other kinds of stealth coating are cross-linked hydrogel, including polyvinylpyr-
rolidone, and cross-linked dextran iron oxide nanoparticles. Torchilin and
Trubetskoi [
19
] discussed the mechanism of action of polymers in imparting
long-circulating properties. Long chains of polymers form a random cloud around
the nanoparticle, thereby preventing protein absorption. Length and density of
polymer are important in protecting the nanoparticle surface from the interactions.
PEGylation is the process of pretreatment of PEG on the surface of NPs. PEG
decreases the affinity of plasma proteins for adsorption on NPs (Fig.
3.3
). There-
fore, PEG prevents the recognition of NPs by Reticulo-Endothelial System (RES)
