Injectable supramolecular hydrogels via inclusion complexation of mPEG-grafted copolyglutamate with α-cyclodextrin

A series of monomethoxy poly(ethylene glycol) (mPEG) grafted copolyglutamates (PmPEGs) were synthesized through ring-opening polymerization (ROP) followed by click chemistry. Supramolecular hydrogels based on polymer inclusion complexes (ICs) between PmPEG and α -cyclodextrin ( α -CD) were prepared in aqueous solution. The rheological measurements indicated their gelation properties were affected by several factors including the mPEG length, graft density and the sample concentration. These hydrogels displayed thermo-sensitive gel-sol transition under appropriate conditions due to the reversible mPEG and α -CD inclusion complexation. These hydrogels also showed pH-sensitive behavior due to the deprotonate of carboxylic acid side groups. The ICs formation of a channel-type crystalline structure induced gelation mechanism was verified by various techniques. In vitro cytotoxicity assays demonstrated that the supramolecular hydrogels are nontoxic and cytocompatible.