Methacrylamide polymers with hydrolysis-sensitive cationic side groups as degradable gene carriers

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Gene Therapy

Background:

• Nonviral gene delivery systems are crucial for therapeutic applications.
• Developing efficient and safe DNA delivery vectors remains a significant challenge.
• Hydrolyzable cationic polymers offer potential for controlled DNA release.

Purpose of the Study:

• To synthesize and evaluate water-soluble polymers with hydrolyzable cationic side groups as DNA delivery systems.
• To investigate the DNA condensation, hydrolysis rates, DNA release kinetics, transfection activity, and cytotoxicity of these novel polymers.
• To compare the performance of these polymers against a benchmark nonviral vector (pEI).

Main Methods:

• Synthesis of water-soluble polymers with varying hydrolyzable cationic side groups.
• DNA condensation into polyplex nanoparticles.
• In vitro hydrolysis studies at 37°C and pH 7.4 to determine half-lives.
• DNA release studies from polyplexes under physiological conditions.
• In vitro transfection assays and cytotoxicity assessments.

Main Results:

• Polymers successfully condensed plasmid DNA into positively charged nanoparticles.
• Hydrolysis rates of cationic side groups varied significantly, with HPMA-DEAE showing the fastest rate (2h half-life) and HPMA-DMAPr the slowest (70h half-life).
• Polyplexes demonstrated controlled DNA release, with intact DNA released within 24-48 hours.
• pHPMA-DEAE and pHPMA-MPPM polyplexes exhibited the highest transfection activity, outperforming pEI.
• These polyplexes maintained transfection activity in serum and showed significantly lower in vitro cytotoxicity than pEI.

Conclusions:

• pHPMA-based polyplexes are effective biodegradable vectors for nonviral gene delivery.
• The tunable hydrolysis rates of the cationic side groups allow for controlled DNA release.
• These novel polymers present a safer and potentially more effective alternative to existing gene delivery systems.