Biomedical Engineering Reference
In-Depth Information
Polycations of dextran, pullulan, and arabinogalactan grafted with
oligoamines of 2 to 4 amino groups were also investigated and were
found effective in gene delivery.
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2.3.3.1
Chitosan
Chitosan is a cationic linear polymer obtained from chitin comprising
copolymers of β(1-4)-glucosamine and randomly located N-acetyl-
D-glucosamine. It has been proved to be biodegradable, bio-
compatible, non-antigenic, non-toxic, and biofunctional polymer.
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It can be fully or partially deacetylated form of chitin; the degree
of deacetylation of typical commercial chitosan is usually between
70% and 95%, and the MW ranges between 10 and 1000 kDa.
Chitosan is a non-toxic polymer, degraded by lysozymes
into common amino sugars. Being cationic and biodegradable in
nature, it has been widely used as gene delivery vector.
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Due to the
high positive charge, it can easily form polyelectrolyte complexes
with negatively charged nucleotides by electrostatic interactions.
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NOVAFECT chitosans are ultrapure chitosan oligomers that were
marketed as carriers for non-viral gene therapy. Klausner
et al.
have
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reported chitosan-DNA nanoparticles based on NOVAFECT.
Chitosan both in native oligomer form as well as copolymer is
used in gene delivery.
transfection studies demonstrated
the ability of oligomeric chitosan-DNA nanoparticles to effectively
transfect COS-7 cells. Oligomeric chitosan-DNA nanoparticles were
evaluated for the treatment of ocular diseases of the cornea and for
various other applications. Looking to various roles of chitosan to
play in siRNA delivery, a novel chitosan-based siRNA nanoparticle
delivery system has been proposed.
In vitro
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To improve the transfection
efficiency of chitosan, PEI (MW 1.8 kDa) was linked to chitosan
to form a complex by Gao
60
et al.
However, Weecharangsan
et al.
evaluated chitosan lactate (CL) as a DNA complexing agent, for its
efficiency in transfecting green monkey fibroblasts, and effect on
cell viability was compared with PEI. Results suggested advantage
of CL for
gene transfection, with the ease of preparation of
polymer/DNA complexes and low cytotoxicity.
in vitro
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prepared a series of chitosan-graft-PEI (chitosan-g-
PEI) copolymers as gene carriers with high transfection efficiency
and low cytotoxicity. Chitosan-g-PEI interacts efficiently with pDNA,
and optimal transfection efficiency was observed with significantly
lower toxicity compared with PEI (25 kDa). Toxicity increased
Wang
et al.
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