A cyclodextrin microgel for controlled release driven by inclusion effects

A novel intelligent delivery system based on the environment dependence of the inclusion effect of beta-cyclodextrin (beta-CD) with guest molecules, using a beta-CD polymer (CDP) microgel as carrier, is proposed. Compared with smart hydogels, which are driven by the phase-volume transition, controlled release from the CDP microgels is driven by host-guest inclusion effects. With the pH-dependent inclusion complexation of methyl orange (MO) with beta-CD as a model system, the behaviour of the controlled release of a CDP microgel was tested by changing the pH, showing that the mechanism is reasonable. Schematic illustration of the pH-dependent inclusion complexation of MO with beta-CD in the CDP microgel.