Synthesis Of Multilysinated-PEG-b-PCL Amphiphilic Aiblock Copolymers And Their Self-assembling Behaviors

Nowadays, micelles prepared with bioresorbable amphiphilic block copolymers used as nanosized carriers for delivery of anti-cancer drugs have become a hot point in biomedical engineering research. However, how to obtain targeted micelles with small size is still an important problem to be solved.In this research, a novel amphiphilic diblock copolymer Lysn-PEG-b-PCL with multi lysine structural units at the end of hydrophilic PEG block was synthesized. The number of the lysine structural units can be controlled by the branching coefficient of lysines. The structure and molecular weight of the copolymers were characterized by 1H NMR and GPC respectively. DLS and TEM measurements show that the copolymers can self-assemble into spherical micelles with diameter 30 to 100nm. The sizes of the micelles decrease as the number of branched lysine structural units increases. The polymeric micelles have positively charged surfaces and theirζpotential increases when the number of the branched lysine structural units increases. Such positively charged micelles on the surfaces can improve cell-adhesion efficiency and this is important for the drug delivery targeting and tissue engineering. In addition, the hydrophobic PCL block cores of the micelles can load the hydrophobic anti-cancer drug.