Composite hydrogels filled with inclusion complexes made from β-cyclodextrins with poly(propylene glycol) bisamine

A novel kind of composite hydrogel filled with inclusion complexes (ICs) made from β-cyclodextrins (β-CDs) with amine-terminated poly(propylene glycol) (PPG-BA) was prepared by copolymerization of methacryloyl end-capped poly(l-lactide)-poly(ethylene glycol)-poly-(l-lactide) macromer (DMPEGL) with acrylic acid (AA) in water under UV irradiation. Owing to the hydrogen bonding interaction of -COOH in AA on the network backbones with -NH₂ and -OH in ICs embedded in the crosslinked network, the composite hydrogels are different from those without ICs in their swelling and degradation behaviors. Furthermore, adding ICs into the network results in the mechanical properties being significantly improved. The mass loss test conducted in water indicates that they degrade by following a dual degradation mechanism, that is, not only β-CDs slipping from the polymer axles and then escaping out of the hydrogel network, but also the bulk hydrogel network hydrolyzing itself to lose the weight. These composite hydrogels show potential to be used as biomaterials for tissue engineering scaffolds and carriers of drugs with controlled release.