Thermo-triggerable self-assembly comprising cinnamoyl polymeric ß cyclodextrin and cinnamoyl Pluronic F127.

Thermo-triggerable self-assembly was prepared by co-dissolving cinnamoyl Pluronic F127 (CinPlu) and cinnamoyl polymeric ß cyclodextrin (CinPßCD) in an aqueous phase. On TEM photo, the CinPlu/CinPßCD self-assembly was 100-200nm in diameter. The specific loading of Nile red (NR) in the assembly was calculated to be 5.5% (wt NR/wt polymer), and the molar ratio of NR to ßCD residue in the assembly was about 0.89:1. No significant release of NR from the assembly was observed at 10°C and 20°C. However, when the temperature was raised to 30°C, 40°C, 50°C, and 60°C, the cumulative release amount in 5min was 17%, 25%, 32%, and 52%, respectively. The specific loading of doxorubicin (DOX) in the assembly was about 6.8% (wt DOX/wt polymer) (corresponding to the molar ratio of DOX to ßCD residue was about 0.41:1). The DOX release from the assembly was proportional to the temperature of release medium. NR and DOX were likely to be expelled out of the cavity of ßCD residue by the interaction of the thermally hydrophobicized Pluronic F127 chain (molecular piston) and the cavity of ßCD residue (cylinder). After 4h-incubation with KB cell, DOX loaded in CinPlu/CinPßCD self-assembly was found to be internalized into the cancer cell more than free DOX, observed on a confocal laser scanning microscope and a fluorescence activated cell sorter. CinPlu/CinPßCD self-assembly enhanced the in vitro anti-cancer activity of DOX against KB cell without increasing significantly the in vitro toxicity of DOX against Raw264.7 cell.