Supramolecular hydrogels based on poly (ethylene glycol)-poly (lactic acid) block copolymer micelles and α-cyclodextrin for potential injectable drug delivery system

A supramolecular hydrogel system was prepared by the host-guest interaction between the α-cyclodextrin (α-CD) and poly (ethylene glycol) (PEG) chains of the poly (ethylene glycol)-block-poly (lactic acid) (PEG-b-PLA) micelles. The formation of inclusion complex (IC) crystals between α-CD and the PEG chains of the micelles was verified by different techniques. Rheological studies indicated that the gelation kinetics and the mechanical strength of the hydrogels could be modulated by the α-CD concentration. Also, the shear-thinning and self-healing properties of the hydrogels were confirmed. Doxorubicin (DOX) could be encapsulated into the hydrogels via the micelles and be released from the hydrogels sustainably, with the release rate dependent on the α-CD concentration. The released DOX showed higher inhibition efficacy against HeLa cells compared with the free drug. These attractive features, together with the superior biocompatibility, make the present hydrogels an potential injectable drug delivery system for tumour treatment.