Facile preparation of 2-methylene-1,3-dioxepane-based thermoresponsive polymers and hydrogels

Abstract

Thermoresponsive and degradable hydrogels are considered promising materials for the development of smart drug delivery carriers that can be applied in the human body. However, the synthesis of a thermoresponsive degradable hydrogel with desirable properties is challenging. Here, we prepared thermoresponsive degradable copolymers and hydrogels by radical copolymerization of 2-methylene-1,3-dioxepane and N,N-dimethylacrylamide. The obtained polymers exhibited low critical solution temperature-type phase separation and a swelling-deswelling behavior. Under alkaline conditions (pH 11.3), these materials degraded and turned into water-soluble oligomers. In addition, the hydrogels self-degraded in PBS due to the decreased pH of the inner hydrogel. The prepared thermoresponsive degradable polymers and hydrogels have potential applicability as stimuli-responsive drug delivery carriers and cell culture scaffolds. Thermoresponsive degradable copolymers and hydrogels were synthesized by radical copolymerization of 2-methylene-1,3-dioxepane (MDO) and N,N-dimethylacrylamide (DMAAm). These prepared materials showed thermoresponsive property through the balance of hydrophobic MDO and hydrophilic DMAAm in the polymer chain. Under alkaline conditions (pH 11.3), these materials degraded and turned into water-soluble oligomers. In addition, the hydrogels self-degraded in PBS due to the decreased pH of the inner hydrogel. The prepared thermoresponsive degradable hydrogels are expected as stimuli-responsive drug delivery carriers and cell culture scaffolds.