NOVEL CATIONIC AND HYDROPHOBIC PULLULAN DERIVATIVES AS DNA NANOPARTICULATE CARRIERS

A novel cationic associating pullulan derivative (DBAP-P) was synthesized using pullulan as hydrophilic backbone and (dibuthylamino) propyl carbamate groups as pendant cationic and hydrophobic segments. The structural characteristics of this polymer were investigated by FT-IR, H-1- and C-13-NMR spectroscopy. The degree of substitution was found to be 0.36 cationic moieties per structural unit of pullulan. The intrinsic viscosity of the DBAP-P sample was calculated using Fedors' and Wolf's models. The critical aggregation concentration (cac) value of 0.1 g/dL determined by fluorescence measurements in the presence of pyrene, as probe, was confirmed by capillary viscosimetry and dynamic laser scattering (DLS). DNA was loaded into the DBAP-P particles by the osmosis based method. The mean diameter and zeta potential of DNA-loaded particles in aqueous solutions, as determined by DLS, decreased with increasing the DNA/DBAP-P ratio for the same polymer concentration. AFM images demonstrated that the DBAP-P and DNA-loaded DBAP-P nanoparticles had a spherical shape.