Effect of polyethylene oxide blocks or grafts on the physicochemical properties of poly(2-N-(dimethylaminoethyl) methacrylate) DNA complexes

The synthesis and the physicochemical evaluation of a series of polyethylene oxide (PEO) containing polyamines are described as potential vectors in gene therapy. Two different types of vectors were synthesized: PEO block copolymers and copolymers containing PEO grafts. The building unit of the polyamine is 2-N-(dimethylaminoethyl) methacrylate. All polymers are able to condense DNA according to dynamic light scattering measurements and ethidium bromide exclusion tests. Complexes of PEO block copolymers and DNA show a stability comparable to that of the homopolymer poly(2-N-(dimethylaminoethyl) methacrylate) (PDMAEMA). Polymers with a PEO graft show a lower stability compared to the unmodified polymer. Incorporation of a PEO graft resulted in a decrease in the zeta potential of the complexes at all charge ratios. The interaction of a serum albumin with complexes of DNA and PEO containing polymers was studied at different protein concentrations. Polymers with a PEO graft show a lower interaction with serum albumin compared to the homopolymer based on turbidity measurements.