Cationic Polymers for the Delivery of Therapeutic Nucleotides - Nanotechnology for the Delivery of Therapeutic Nucleic Acids - page 47

MW polymers have reduced DNA condensation abilities and their
marginal transfection properties; thus biodegradable polymers of
high MW have been developed with reduced toxicity and high gene
delivery mechanisms.

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2.5 Biomedical Applications

Gene therapy shows much promise in therapies for various genetic
diseases, cancers, viral infection, and cardiovascular disorders.
Gene delivery includes both the delivery of pDNA (encoding
therapeutic proteins) and RNA interference. DNA delivery provides
a corrective action by expressing suppressor proteins to suppress
cancer growth or activate apoptosis, while RNA interference delivery
produces gene silencing to inhibit cellular protein expression or
induce apoptosis.

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The design and development of nucleic acids
based therapeutics for the treatment of diseases arising from
genetic abnormalities has made significant progress over the past
few years. Cationic polymers are the ultimate vectors that are
versatile for the nucleic acid delivery with ease of manipulation.
Some important biomedical applications of cationic polymers are
discussed underneath.

2.5.1 Tumor Therapy

Cationic polymer-based nanoparticles emerged as a promising
nanosize carrier systems to the tumor cell level with a wide range
of modification and application possibilities.

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Nanoparticulates
based on cationic polymers like PEI, PLL, and chitosan were blended
effectively to deliver nucleic acid as well as anticancer agents to tumor
cells. Due to the favorable cellular interaction, internalization, and
stronger interaction properties, cationic polymers are considered
as promising delivery systems for cancer therapy through both
systemic and local administration as compared to polymers with
neutral or negative charge. d'Ayala reported synthesis of

nanosized particles consisting of HMW PEI (25 kDa) crosslinked
with PCL (50-60 kDa). Results are extremely promising in terms
of low cell toxicity and high transfection efficiency. These biological
effects might be related to the peculiar DNA binding to covalently
connected polymeric nanoparticles, without the formation of

et al.