Abstract
This work presents the synthesis of biocompatible and biodegradable amphiphilic copolymers for the formation of anticancer drug delivery systems. These copolymers consist of a poly-(ε-caprolactone) (PCL) chain, a biocompatible and biodegradable hydrophobic polyester, on which hydrophilic oligomers of dextrane or chitosane are grafted. These new copolymer structures are called “reverse” structures, the “classic” ones being made of a polysaccharide chain with PCL grafts. The PCL chain was propargylated via an anionic method developed by our team, while azide functions were grafted on oligosaccharides at a chain end of dextrane, but along the chain in chitosan, thanks to its amine functions. Copolymers were obtained by CuAAC click coupling between the activated PCL and oligosaccharides. In the case of chitosan, the amines of the chain allowed the coupling of mannose squarate, a cancer cell targeting agent, as well as a functionalization in the form of thiols which allow coupling by thiol-yne reaction on propargylated PCL. These copolymers form nano objects in aqueous media which, in the case of the PCL-g-dextrane structure, are forming micelles that encapsulate doxorubicin, which is further released in a pH- dependent way. Biological studies have shown that these charged micelles are toxic to cancer cells and not to healthy cells and are preferentially internalized by cancer cells. These results demonstrate a high degree of selectivity of action against tumor cells.