New copolymers graft of α,β-poly(N-2-hydroxyethyl)-d,l-aspartamide obtained from atom transfer radical polymerization as vector for gene delivery

New cationic α,β-poly(N-2-hydroxyethyl)-d,l-aspartamide (PHEA) graft copolymers were synthesized by ATRP, using diethylamino ethyl methacrylate (DEAEMA) as monomer for polymerization, yielding polycations (PHEA-pDEAEMA) able to condense DNA. Then, consecutive ATRP conditions were set up on PHEA-pDEAEMA to obtain copolymers containing also hydrophilic chains (PHEA-IB-pDMAEMA-pPEGMA) able to improve biocompatibility of polyplexes and to provide them stealth properties. Agarose gel studies showed that the copolymers effectively condensed plasmid DNA to form polyplexes. Light scattering studies were used to analyze the size and the ζ-potential of these polyplexes, showing that copolymers were able to condense the pDNA leading to the formation of nanoscale systems. The copolymers PHEA-IB-pDEAEMA showed high cytocompatibility that was improved with the presence of PEGMA units in the side chain.The transfection efficiency (luciferase) of polyplexes obtained with all copolymers was evaluated on B16F10 cell line obtaining a moderate transfection efficiency in comparison with bPEI that can be explained, supposing a low release of pDNA from polyplexes at endocellular level.