Thermo- and pH-sensitive hydrogels containing the β-cyclodextrin moiety for controlled protein release

In this study, two kinds of dual-stimuli-responsive (pH and temperature) hydrogels were prepared through the copolymerization of acrylic acid (hydrophilic monomer) and N-isopropylacrylamide (thermosensitive monomer) with a modified beta-cyclodextrin crosslinker or N,N'-methylenediacrylamide in aqueous solution. The swelling properties of these hydrogels, including the pH and temperature dependences of their equilibrium swelling ratios, their shrinking kinetics, and their de-swelling behavior, were investigated. The protein bovine serum albumin was chosen as a model drug to measure their release behavior at different pH values and temperatures. The results revealed that the hydrogel that incorporated the beta-cyclodextrin crosslinker exhibits improved properties and could have a wide range of potential uses in biomedicine.