Solution Behavior of Hydrolyzed Gradient Methyl/Phenyl Oxazoline Copolymers and Complexation with DNA

Partial hydrolysis of 2-methyl-2-oxazoline/2-phenyl-2-oxazoline gradient copolymers (MPOx copolymers) results in amphiphilic copolymers containing cationic ethylene imine, neutral hydrophilic 2-methyl-2-oxazoline, and hydrophobic 2-phenyl-2-oxazoline segments (HMPOx copolymers). The solution behavior of the HMPOx copolymers has been investigated in water, phosphate buffer saline (PBS), and fetal bovine serum (FBS) by static, dynamic, and electrophoretic light scattering and fluorescence spectroscopy. The copolymers form stable spherical aggregates in aqueous media with positive surface charge. The aggregates are found to interact extensively with proteins in FBS solutions. Soluble HMPOx/DNA complexes have also been formed in aqueous media at certain HMPOx/DNA compositions due to electrostatic interactions. The polyplexes have been studied in terms of structure and colloidal stability.