The morphology and fabrication of nanostructured micelle by a novel block copolymer with linear-dendritic structure.

We report here a novel approach to fabricate a nanostructured micelle as potential drug carriers and the relationship between the morphological structure and the preparation condition. The polymeric micelle aggregates constructed by self-assembly compose of the poly(ε-caprolactone)/monomethoxy poly(ethylene glycol) linear-dendritic block copolymers. The corresponding copolymers were synthesized by using ring opening polymerization of ε-caprolactone (CL) and a dendritic poly(ether-amide) (DPEA-OH) as an initiator, then coupling with the isocyanate end-capped linear monomethoxy polyethylene glycol. Fluorescence spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM) were performed to characterize the copolymer micelles. The critical micelle concentration (CMC) was determined to be 1.623 mg/L. The hydrodynamic radius (Rh) and the polydispersity index (PDI) are influenced by the concentration of the micelle solutions. The multiple morphologies of the micelle aggregates, including spheres, rob-like dendritic structure and vesicles were observed, which the variety depends on the various preparation conditions. The nanostructured micelles based on the linear-dendritic block copolymer possess the strong thermodynamic stability and the power of solubilization of hydrophobic drug molecules.