Biomedical Engineering Reference
In-Depth Information
2.5.3
DNA Vaccination
DNA vaccination is one of the most significant biomedical
applications
of
cationic
polymers
and
has
attracted
many
107
researchers to put more effort.107
Numerous cationic polymers
like PEI, poly(amino ester)s, etc., are successively blended for
DNA vaccination with significant enhancement in transfection
efficiency. DNA-based vaccine directed to tumor-specific antigens
is an attractive strategy in cancer prevention and therapy. In view
of the poor immunogenicity of most tumor-associated antigens,
studies were carried out to examine the adjuvant effect of PEI on the
efficacy of cancer vaccine strategy. Results obtained illustrated the
potential use of PEI as an adjuvant in DNA-based cancer vaccination
for induction of protective and therapeutic immunity.
108
Oster
et al.
studied cationic microparticles for DNA adsorption formulated by
blending PLGA with different cationic agents PEI or CTAB (cetyl-
trimethyl-ammonium-bromide). Microparticles with 10% PEI
efficiently adsorbed DNA and protected DNA from enzymatic
degradation, and, thus, PLGA+PEI microspheres can be used as an
adjuvant delivery system for DNA.
109
2.5.4
Lung and Liver Delivery
Gene therapy aimed at the respiratory epithelium holds therapeutic
potential for diseases such as cystic fibrosis and lung cancer. PEI
and other cationic polymers have been utilized for gene delivery to
the airways. Kleemann
described a new modification of PEI, in
which an oligopeptide related to the protein transduction domain
of HIV-1 TAT was covalently coupled to PEI (25 kDa) through a
heterobifunctional PEG spacer resulting in a TAT-PEG-PEI conjugate.
TAT-PEG-PEI represents a new approach to non-viral gene carriers
for lung therapy, comprising protection for pDNA, low toxicity, and
significantly enhanced transfection efficiency.
et al.
110
Novel cationic polymer, like dextran-spermine (D-SPM), has
been found to mediate gene expression in a wide variety of cell
lines and
in vivo
through systemic delivery. Recently, Abdullah
et al.
determined the optimal conditions for gene expression of D-SPM/
pDNA in cell lines and in the lungs of BALB/c mice via instillation
delivery.
studies showed that D-SPM could partially protect
pDNA from degradation by nuclease and exhibited optimal gene
In vitro
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