Fabrication of poly(ethylene glycol)-based cyclodextrin containing hydrogels via thiol-ene click reaction

A simple and efficient methodology for the fabrication of poly(ethylene glycol) (PEG) based chemically cross-linked hydrogels containing discrete beta-cyclodextrin (beta-CD) units is outlined. Hydrogels were synthesized using homo-bifunctional linear PEGs containing allyl groups and heptavalent thiol-functionalized beta-CD as crosslinkers via the radical-induced thiol-ene click chemistry. Various hydrogels comprising of different molecular weight PEGs and varying crosslinker feed were investigated in terms of their physical properties such as water uptake capacity, surface morphology and rheological behaviors. Uptake and controlled release of a poorly water-soluble drug, namely, puerarin was demonstrated using these hydrogels. The drug uptake and release was found to be depended on the hydrogels composition. Benefiting from the photochemically induced gel formation, the methodology was extended to fabricate hydrogel micro-structures on solid substrates. (C) 2014 Elsevier Ltd. All rights reserved.