Dual pH-sensitive supramolecular micelles from star-shaped PDMAEMA based on β-cyclodextrin for drug release.

Star-shaped poly(2-(dimethylamino)ethyl methacrylate) based on β-cyclodextrin (β-CD-(PDMAEMA)7 ) was synthesized by means of atomic transfer radical polymerization (ATRP). Dual pH-sensitive supramolecular micelles were formed from β-CD-(PDMAEMA)7 and benzimidazole modified poly(ε-caprolactone) (BM-PCL) through the host-guest interactions between β-CD and benzimidazole. The supramolecular micelles have regular spherical structure with hydrophobic β-CD/BM-PCL as the core and pH-sensitive PDMAEMA as the shell. The hydrophobic PCL as well as the hydrophobic cavity of β-CD can efficiently encapsulate doxorubicin (DOX) with the drug-loading content and entrapment efficiency up to 40% and 86%. The drug release from micelles accelerated when the pH decreased from 7.0 to 2.0 and the temperature increased from 25 °C to 45 °C. MTT assay showed that drug loaded supramolecular micelles exhibited excellent anti-cancer activity than free DOX. These supramolecular micelles have promising potential applications as intelligent nanocarriers in drug delivery system.