Preparation and in vitro pH-responsive drug release of amphiphilic dendritic star-block copolymer complex micelles

Amphiphilic dendritic star-block copolymer PCL-b-PDMAEMA composed of poly(e-caprolactone) and poly(2-(N,N-dimethylamino)ethyl methacrylate) was synthesized successfully. In an aqueous solution, the copolymer could simultaneously self-assemble into unimolecular micelles and multimolecular mielles with mean diameters of about 28 nm and 190 nm, respectively. Dynamic light scattering measurements of these copolymer micelles showed bimodal size distribution, in vitro drug release behavior of the complex micelles loading camptothecin indicated that the rate of drug release could be effectively controlled by altering the pH values of the environment. The cytotoxicity assay confirmed the low cytotoxicity of the complex micelles and the significant drug efficacy. The confocal laser scanning microscopy demonstrated that the drug-loaded micelles could penetrate the cell membrane and be internalized into cytoplasm and cell nucleus of HeLa cells. Thus, the pH-responsive dendritic PCL-b-PDMAEMA micelles could be promising drug delivery vehicles for pharmaceutical and biomedical applications. (C) 2014 Elsevier B.V. All rights reserved.