Biomedical Engineering Reference
In-Depth Information
nanoparticles coated with b-CD coupled to amino acids significantly improved
the siRNA delivery in vitro. They further modified CdSe/ZnSe QDs with
L
-
Arg- or
L
-His-coupled b-CD to simultaneously deliver DOX and siRNA in
HeLa cells.
126
These multifunctional QDs were promising vehicles for the co-
delivery of nucleic acids and chemotherapeutics and for real-time tracking of
treatment.
Chertok et al. developed PEI-modified magnetic nanoparticles (GPEI) as a
potential vascular drug/gene carrier to brain tumors. The results showed that
GPEI exhibited high cell penetrability and low cell toxicity properties, which
are highly desirable for intracellular drug/gene delivery.
127
In addition, GPEI
could be magnetically captured in gliomales ions following clinically viable
intra-carotid administration. The extent of GPEI accumulation was 5.2-fold
higher than that of commercially available G100 magnetic nanoparticles in the
tumor lesions, but not in the contra-lateral normal brain, revealing higher
target selectivity of cationic nanoparticles. These results warrant further
investigation of GPEI as a potential nanocarrier for drug/gene delivery to
glioma lesions.
Ribonucleic acid interference (RNAi) is a powerful molecular tool that has
potential to revolutionize the treatment of cancer. One major challenge to
applying this technology for clinical applications is the lack of site-specific
carriers that can effectively deliver short interfering RNA (siRNA) to cancer
cells. Veiseh et al. developed a magnetic nanoparticle platform consisting of a
superparamagnetic iron oxide (Fe
3
O
4
) core coated with a cationic copolymer
of chitosan-grafted-PEG and PEI for nonviral DNA delivery.
128
This unique
formulation has shown the ability to safely deliver plasmid DNA in vivo and
transfect brain tumor cells. They further functionalized these nanovectors with
siRNA and a tumor-targeting peptide, chlorotoxin (CTX), to improve tumor
specificity and potency.
129
The results showed that cellular internalization and
gene knockdown efficiency of the nanovectors were enhanced through
targeting with CTX. MRI demonstrated the ability of this nanovector
construct to generate specific contrast enhancement of glioblastoma cells.
These findings suggested that this CTX-enabled nanoparticle carrier may be
well suited for the delivery of RNAi therapeutics to brain cancer cells.
d
n
4
y
3
n
g
|
3
4.6.7 Other Types
Recently, Xu et al. reported that ethanolamine (EA)-functionalized poly(-
glycidyl methacrylate) (termed PGEA) vectors had excellent transfection
efficiency, while exhibiting very low toxicity.
130
As ethylenediamine (ED) has a
similar molecular mass to EA but possesses double amino groups, they further
investigated the structural effects of EA and ED on transfection. Different EA-
and ED-functionalized PGMA (PGEAED) vectors, as well as ED-functionalized
PGMA (PGED) vectors, were proposed and compared. The results indicated
that the flanking non-ionic hydrophilic hydroxyl groups had a crucial effect
on the gene transfection process. PGEAED and PGED showed outstanding
