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

Abstract

Thermo-triggerable self-assembly was prepared by co-dissolving cinnamoyl Pluronic F127 (CinPlu) and cinnamoyl polymeric beta cyclodextrin (CinP beta CD) in an aqueous phase. On TEM photo, the CinPlu/CinP beta CD self-assembly was 100-200 nm 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 beta CD residue in the assembly was about 0.89:1. No significant release of NR from the assembly was observed at 10 degrees C and 20 degrees C. However, when the temperature was raised to 30 degrees C, 40 degrees C, 50 degrees C, and 60 degrees C, the cumulative release amount in 5 min 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 beta CD 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 beta CD residue by the interaction of the thermally hydrophobicized Pluronic F127 chain (molecular piston) and the cavity of beta CD residue (cylinder). After 4 h-incubation with KB cell, DOX loaded in CinPlu/CinP beta CD 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/CinP beta CD 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. (C) 2016 Elsevier B.V. All rights reserved.