Supramolecular hydrogels from inclusion complexation of α-cyclodextrin with densely grafted chains in micelles for...

An amphiphilic Py-PCL-b-POEGMA copolymer was prepared by the combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). Based on the host-guest inclusion complexation of α-CD with densely grafted chains of the POEGMA shell in Py-PCL-b-POEGMA micelles, supramolecular micellar hydrogels were obtained by adding α-CD into Py-PCL-b-POEGMA micellar solutions. Resulting from the dissociation of α-CD from the ICs upon heating, the Py-PCL-b-POEGMA IC-based supramolecular hydrogels presented thermo-responsive properties. As they were heated, the IC-based hydrogels underwent gel-sol transformation because of the breakage of the physical cross-links. Benefiting from the fluorescent pyrene group in the Py-PCL-b-POEGMA copolymer, the system showed fluorescent properties. And the fluorescent intensity decreased obviously and regularly during the sol-gel transformation process, which makes it possible to detect the sol-gel transformation through sensing the fluorescent intensity of the system. Due to the biodegradable and biocompatible properties, the IC-based hydrogels were used as carriers for delivery systems. The hydrogels showed good properties for controlled release, and the release rate and level can be controlled by temperature.