Poly(citric acid)-Poly(ε-caprolactone)-Poly(citric acid) ABA Amphiphilic Block Copolymer

Recently, a growing research interest has been shown in the synthesis of block copolymers consisting of polycaprolactone with properties that can be tailored by introducing functionalgroups, such as carboxyl, hydroxyl, amino, etc. The functional groups in the copolymers structure can improve their affinityto proteins and cells, and can combine covalently or ionically with drugs, antibodies or DNAs [1,2]. For example, Zhu et al.prepared micelles from biamphiphilic triblock copolymerpoly(ethylene glycol)-b-poly(e-caprolactone)-b-poly(acrylic acid) (PEG-b-PCL-b-PAA) as new multifunctionalnanocarriers to delivery anticancer drugs. The PAA block can be loaded with drugs and imaging agents that react with carboxyl groups, while the PCL block can trap different hydrophobic drugs [3]. In this context, in order to targeting drug delivery, we aimed at developing fully biodegradableamphiphilic ABA type block copolymer containing a linear polycaprolactone block (B) and a branched block bringing both hydrophilicity and functional group along the backbonefor biomolecule coupling, namely a poly (citric acid) (PCA) block (A), by melt polycondensation reaction of citric acid and hydroxyl telechelic poly(ε-caprolactone