Synthesis of a barbell-like triblock copolymer, poly(l-lysine) dendrimer-block-poly(ethylene glycol)-block-poly(L-Lysine) dendrimer and its self-assembly with plasmid dna

摘要

Block copolymers composed of poly(ethylene glycol) (PEG) have been used for many drug carriers because of their high solubility in water, non-immunogenicity and improved biocompatiblit. PEG has been coupled to polycationic polymers (e.g., poly(L-lysine), polyspermine and polyethylenimine)~1-3 or liposomes to improve the solubility of complexes with DNA and transfection efficiency. Poly(L-lysine) dendrimer~4 is another polycationic dendrimer containing large number of surface amines and considered to be capable of electrostatic interaction with polyanions, such as nucleic acids.~5 Here we report another new concept of copolymer which takes advantage of the above-mentioned copolymers and dendrimers, poly(L-lysine) dendrimer-block-poly(ethylene glycol)-block-poly(L-lysine) dendrimer (PLLD-PEG-PLLD), a barbell-like ABA type triblock copolymer (Figure 1). We have demonstrated the supramolecular self-assembly of this series of hybrid triblock copolymers with plasmid DNA~6.