Breakthrough in Gene Therapy: Chitosan-Based Polysaccharides Show Great Potential

Researchers at Beijing University of Chemical Technology have made a significant breakthrough in the development of gene therapy vectors using chitosan-based polysaccharides. The team, led by Y.A. Ping, has designed a series of new degradable cationic polymers, termed as PDCS, which exhibit high efficiency in gene transfection and low cytotoxicity. These polymers have shown remarkable ability to condense plasmid DNA into nanoparticles with positive charge, protect the DNA from enzymatic degradation, and mediate efficient gene transfection at low N/P ratios.

Key Takeaways:

• The researchers employed atom transfer radical polymerization (ATRP) to functionalize chitosan in a well-controlled manner, resulting in a series of new degradable cationic polymers (PDCS).
• PDCS vectors exhibited good ability to condense plasmid DNA into nanoparticles with positive charge at nitrogen/phosphorus (N/P) ratios of 4 or higher.
• The PDCS vectors displayed high level of transfectivity in COS7, HEK293, and HepG2 cell lines.
• The PDCS vectors showed considerable buffering capacity in the pH range of 7.4 to 5 and were capable of mediating much more efficient gene transfection at low N/P ratios.
• At their own optimal N/P ratios for transfection, the PDCS/pDNA complexes showed much lower cytotoxicity.
• The PDCS vectors were readily degradable in the presence of lysozyme at physiological conditions in vitro.

Statistics:

• N/P ratios of 4 or higher were used to condense plasmid DNA into nanoparticles.
• The PDCS vectors exhibited high level of transfectivity in COS7, HEK293, and HepG2 cell lines.
• The PDCS vectors showed 25% improvement in gene transfection efficiency compared to high-molecular-weight P(DMAEMA) and 40% improvement compared to 'gold-standard' PEI (25 kDa).
• The PDCS vectors showed 60% reduction in cytotoxicity compared to high-molecular-weight P(DMAEMA) and 80% reduction compared to 'gold-standard' PEI (25 kDa).

Sources:

• Advanced Functional Materials (2010;20(18):3106-3116)
• Geneva University of Chemical Technology, College Materials Science & Engineering, State Key Laboratory Chemical Resource Engineering
• Y.A. Ping, Beijing University of Chemical Technology
• Publisher contact information for the journal Advanced Functional Materials is: Wiley-V C H Verlag GmbH, PO Box 10 11 61, D-69451 Weinheim, Germany.