Synthesis and characterization of three-dimensional crosslinked networks based on self-assemly of α-cyclodextrins with thiolated 4-arm PEG using a three-step oxidation

A kind of novel three-dimensional crosslinked networks based on the self-assemly of α-CDs with thiolated four-arm PEG was prepared by thiol-disulfide interchange reaction using a three-step oxidation. The supramolecular structure of the resulting hydrogels was characterized via FTIR, ¹H NMR, XRD, DSC and TGA measurements. The results demonstrated that the channel-type crystalline structure of inclusion complexes is still maintained after the multi-step oxidation. According to the swelling and degradation tests, the swelling behaviors and degradation properties can be readily regulated by tuning the feed compositions of α-CDs and PEG-thiolated prepolymer. Furthermore, the threading α-CDs clearly protects disulfide bonds from an attack of a reduced form of glutathione as a result of prolonging the degradation time of the hydrogels in water.