Biomedical Engineering Reference
In-Depth Information
and transfection efficiency of TP conjugates was evaluated. From
the results, TP conjugates showed lower cytotoxicity compared
with the PEI system.
37
Further, to improve specificity and reduce
its cytotoxicity, PEI was modified by PEG to reduce the protein
interaction and cell cytotoxicity of delivery vectors. Thus,
PEG-TF-PEI conjugate as an efficient and safe carrier of pDNA
was synthesized. Nanocomplexes of conjugates with pDNA were
characterized by measuring the particle size and the surface
charge. It was found that transfection efficiency of nanocomplexes
in Jurkat cells was improved and cytotoxicity was decreased
compared with PEI complex.
38
explored the effect of increased
hydrophobicity of the PEI on the efficacy and specificity of gene
delivery. N-alkylated LPEI with varying alkyl chain lengths and
extent of substitution was synthesized and characterized, and
Recently, Fortune
et al.
in
vivo
transfection efficiency, specificity, and biodistribution were
investigated. N-propyl-PEI was found best in the liver and heart,
while N-octyl-PEI improved expression in the kidneys over the
parent PEI polymer. These enhancements in gene expression occur
without changing the plasmid biodistribution. Thus, alkylation does
not alter the cellular uptake but enhances transfection subsequent
to cellular uptake.
39
Further, gold nanoparticles conjugated with low
MW PEI (800 Da) were synthesized (GNP-PEI) and characterized
as gene transfection vectors by Hu
These complexes showed
high efficiency for gene delivery in monkey kidney cells
et al.
. GNP-
PEI exhibited transfection efficiency exceeding 60 fold that of PEI
(25 kDa) in 10% serum medium. All GNP-PEI exhibited mild
cytotoxicity in comparison with that of PEI 25 kDa.
in vitro
40
Similarly,
Sharma
examined the gene transfer efficiency and toxicity of
2 kDa PEI conjugated to gold nanoparticles in the human cornea
et al.
in
vitro
. The results suggest that PEI-GNP are
safe for the cornea and can potentially be useful for corneal gene
therapy.
and rabbit cornea
in vivo
41
2.3.2
Poly(L-lysine)
PLL is one of the first polymers used for DNA condensation. PLL
has a sufficient number of primary amines with positive charges to
interact with the negatively charged phosphate groups of DNA. The
complex formation of PLL and DNA has lot of constraints in clinical
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