Amphiphilic FA-PEG(2000)-OA conjugate was designed, comprising hydrophilic poly(ethylene glycol) (PEG), with a folate targeting moiety and a biodegradable hydrophobic oleic acid (OA) segment at each chain ends. The near-monodisperse flower-shaped folate-functionalized micelles were self-assembled in aqueous solution for the folate receptor (FR)-mediated targeted delivery of the anticancer drug (doxorubicin (DOX)) to cancer cells. The drug loading and in vitro pH responsive controlled release performance revealed that the FA-PEG(2000)-OA micelles had potential application as drug delivery systems (DDS) for hydrophobic anthracycline anti-cancer drugs such as DOX. With the aid of FA-PEG2000-OA micelles as DDS, which was non-cytotoxic in low concentrations, the cancer cell-killing ability of DOX has been obviously enhanced, demonstrating their promising applications to overcome multi-drug resistance (MDR) in tumor treatments. (C) 2016 Elsevier B.V. All rights reserved.