作者：Jinliang Yan, Houyong Luo, Min Chen, Zhaoyang Ye, Yan Zhou, Yan Sun, Yan Xiao, Yan Zhang, Wensong
关键字：Multi-functional Micelles, mPEG-b-PCL Amphiphilic Block
论文来源：期刊
发表时间：2011年

Micelles endowed with multiple functionalities are very attractive in biomedical applications. We report in this paper a facile way to prepare novel amine-functionalized monomethoxy-poly(ethylene glycol)-b-poly(ε-caprolactone) (mPEG-b-PCL) amphiphilic block copolymers for the formulation of versatile micelles. In our synthetic route,monomethoxy-poly(ethylene glycol)-b-poly[ε-caprolactone-co-γ-(carbamic acid benzyl ester)-ε-caprolactone] [mPEG-b-P(CL-co-CABCL)] copolymers were synthesized via ring-opening polymerization (ROP) of ε-caprolactone (CL) and a newly developed monomer, γ-(carbamic acid benzyl ester)-ε-caprolactone (CABCL) at varied ratios using mPEG as macroinitiator and Sn(Oct)₂ as catalyst. Subsequent deprotection upon removal of carbobenzoxy (Cbz) group yielded monomethoxy-poly(ethylene glycol)-b-poly(ε-caprolactone-co-γ-amino-ε-caprolactone) [mPEG-b-P(CL-co-ACL)] copolymers bearing primary amine functional groups on the PCL block. The polymers were characterized with NMR, FT-IR and GPC techniques. Successful formation of micellar structures were demonstrated with these amphiphilic block copolymers showing spherical morphology and narrow particle size distribution ranging from 50 to 150 nm using transmission electron microscopy (TEM) anddynamic light scattering (DLS), respectively.Moreover, it was found that critical micelle concentration was dependent on the compositions of the copolymers. In vitro study demonstrated that the micelles were nontoxic to human fibroblasts based on MTT and live/dead assays. Furthermore, a proof-of-concept usage of amino groups for bioconjugation was illustrated by tagging the copolymer with a fluorophore, FITC. Efficient internalization of FITC-labeled micelles by fibroblast cells could be observed under fluorescence microscopy. Through facile conjugation of chemical moieties such as drugs, peptides, proteins, fluorophores or ligands, micelles prepared with these amine-functionalized mPEG-b-PCL copolymers hold great promise in both biomedical and pharmaceutical applications.