Poly(vinyl benzyl trimethylammonium chloride) Homo and Block Copolymers Complexation with DNA

In this work we focus on the use of novel homo and block copolymers based on poly(vinyl benzyl trimethylammonium chloride) as gene delivery vectors. The homopolymers and block copolymers were synthesized by RAFT polymerization schemes and molecularly characterized. DNA/polymer complexes (polyplexes) in a wide range of N/P (amino-to-phosphate groups) ratios were prepared. The ability of the novel polymers to form complexes with linear DNA was investigated by light scattering, zeta potential, and ethidium bromide fluorescence quenching measurements. The resulting polyplexes were in the size range of 80-300 nm and their surface potential changed from negative to positive depending on the N/P ratio. The stability of polyplexes was monitored by changes in their hydrodynamic parameters in the presence of salt. The novel vector systems were visualized by transmission electron microscopy. The influence of factors such as molar mass, content, and chemical structure of the polycationic moieties as well as presence of a hydrophilic poly[oligo(ethylene glycol) methacrylate] block on the structure and stability of the polyplexes, kinetics of their formation, and effectiveness of the (co)polymers to shrink and pack DNA was discussed.