We developed cyclic RGD-tagged polymeric micellar nanoassemblies for sustained delivery of Doxorubicin (Dox) endowed with significant cytotoxic effect against MG63, SAOS-2, and U2-OS osteosarcoma cells without compromising the viability of healthy osteoblasts (hFOBs). Targeted polymeric micellar nanoassemblies (RGD-NanoStar@Dox) enabled Dox to reach the nucleus of MG63, SAOS-2, and U2-OS cells causing the same cytotoxic effect as free Dox, unlike untargeted micellar nanoassemblies (NanoStar@Dox) which failed to reach the nucleus and resulted ineffective, demonstrating the crucial role of cyclic RGD peptide in driving cellular uptake and accumulation mechanisms in osteosarcoma cells. Micellar nanoassemblies were obtained by nanoformulation of three-armed star PLA-PEG copolymers properly synthetized with and without decoration with the cyclic-RGDyK peptide (Arg-Gly-Asp-D-Tyr-Lys …