Nano-polyplexes from a cationic modification of poly(γ-glutamic acid)

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Gene Delivery Systems

Background:

• Biodegradable and biocompatible polymers are essential for advanced biomedical applications.
• Developing efficient and stable non-viral gene delivery vectors remains a significant challenge.
• Poly(γ-glutamic acid) (PGGAH) offers a promising scaffold for polymer modification due to its inherent safety profile.

Purpose of the Study:

• To synthesize and characterize novel cationic copolymers derived from poly(γ-glutamic acid) (PGGAH).
• To investigate the impact of varying cationic group incorporation on polymer properties and DNA binding.
• To evaluate the potential of these new materials as efficient DNA delivery systems.

Main Methods:

• Synthesis of PGGAH_xTMEA_y copolymers via partial esterification of PGGAH with 2-bromoethyl trimethylammonium bromide (BrETABr).
• Characterization using ¹H NMR, FTIR, TGA, and GPC.
• Assessment of DNA complexation and polyplex formation using dynamic light scattering (DLS) at various N/P ratios.
• Monitoring of polyplex stability, size, and surface charge over two weeks.

Main Results:

• Cationic copolymers (PGGAH_xTMEA_y) with 11-95% cationic group incorporation were successfully synthesized.
• Degree of esterification significantly influenced thermal stability and DNA-binding capacity.
• Higher modification levels enhanced DNA complexation, forming stable polyplex nanoaggregates (80-220 nm).
• Polyplexes exhibited enhanced stability and consistent particle sizes over time, particularly with higher modification degrees.

Conclusions:

• Novel cationic poly(γ-glutamic acid) derivatives were developed with tunable properties for DNA delivery.
• The degree of cationic modification is a critical factor for optimizing DNA binding and polyplex stability.
• These findings highlight the potential of modified PGGAH as a promising platform for developing efficient and stable non-viral gene delivery vectors.