• biodegradable;
  • drug delivery systems;
  • micelles


A mixed micellar system of novel function was designed and synthesized by co-assembling TAT (cell penetrating peptide)-modified poly (ethylene glycol)-poly(l-lactide) (PEG-PLA) copolymer with the drug-conjugated poly(ethylene glycol)-b-poly(l-lactide-co-2-methyl-2-carboxyl-propylene carbonate) (mPEG-b-P(LA-co-MCC)) copolymer. UV-Vis, Matrix-assisted laser desorption/ionization time-of-flight, and XPS were used to ensure the successful modification of the copolymers with TAT and anti-tumor drugs. The size of spherical nanomicelles increased from 50 to 60 nm as of empty polymeric micelles to 100–150 nm as of drug-loaded ones, determined by dynamic light scattering and TEM. Daunorubicin was selected as model drug for in vitro evaluations on different cell lines. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay clearly indicated an improved cell growth inhibition of the TAT-modified mixed micelles. While green fluorescent protein was used as a marker for the mixed micelle, small amount of DMSO was necessary to enhance the accumulation of the mixed micelles in cell lines Caski. Mediated by TAT, mixed micelles containing Apoptin (a tumor-specific apoptosis drug) showed higher level of tumor cell internalization and growth inhibition than that of mixed micelles without TAT modification. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4598–4607, 2013